CN113779113A - Flood dynamic estimation method and system based on rainfall flood space-time process similarity excavation - Google Patents
Flood dynamic estimation method and system based on rainfall flood space-time process similarity excavation Download PDFInfo
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Abstract
The invention provides a flood dynamic estimation method and a system based on rainfall flood space-time process similarity excavation, wherein the method comprises the following steps: acquiring historical and real-time remote sensing inversion observation rainfall, numerical prediction rainfall and hydrological station historical site flood information in a research area, and establishing a historical rainfall flood database; splicing the early stage of the moment, the observed rainfall and the numerical forecast rainfall, and retrieving the rainfall similar to the time-space process and a corresponding historical flood process set 1 by adopting the structural similarity of the structural similarity index and the dynamic time warping DTW; retrieving a historical flood process set 2 with similar time sequence by adopting DTW; merging the sets 1 and 2 to estimate the subsequent flood by the average similar flood process; and updating information along with the time, and realizing dynamic flood estimation. The similarity analysis is expanded to a three-dimensional space-time process from a one-dimensional time sequence, and the accuracy of the estimated subsequent water inflow is higher than that of the traditional method.
Description
Technical Field
The invention relates to G06F: the field of electric digital data processing, in particular to a flood dynamic estimation method and system based on rainfall flood space-time process similarity excavation.
Background
The rain flood process is the result of coupling of factors such as weather system evolution and river basin underlying surface conditions, and although the factors cannot be completely repeated, the weather system dominating one region is not completely and invisibly found, and certain regularity still exists, so that rain flood events occurring in different periods may have certain similarity. Along with the accumulation of the number of meteorological hydrological events and the deepening of cause recognition, a historical rainfall flood database with a certain scale is constructed, on the basis of similarity mining of rainfall flood events, the estimation of the development situation of the flood by utilizing the historical similar rainfall flood process is another important idea for improving the prediction capability, and the method has important significance for safe and efficient utilization of the rainfall flood.
At present, research about rainfall flood similarity excavation is mainly developed based on rainfall flood real-time observation information and historical data, wherein the related rainfall time sequence is mostly the surface average rainfall calculated based on the observation data of a ground rainfall station network, the consideration of rainfall spatial distribution and rainfall landing area positions is lacked, and particularly, the drainage basin with a large water collection area is provided. In addition, precipitation similarity analysis in the existing research only utilizes real-time observation precipitation information, and does not consider the development situation of the late stage of the rain condition.
Disclosure of Invention
The purpose of the invention is as follows: the invention provides a flood dynamic estimation method based on rainfall flood time-space process similarity mining, which comprises four core links of historical rainfall flood database construction, historical flood process retrieval based on rainfall time-space process similarity, historical flood process retrieval based on flood time sequence process similarity, and dynamic estimation based on historical similar flood. The method utilizes observation and forecast information in a coupling mode, corresponding historical similar floods are retrieved according to similarity of time-space processes and similarity of time sequence processes aiming at precipitation and flood respectively, and the historical similar floods considering occurrence and development processes of rainfall flood more comprehensively can be obtained by integrating retrieval results of the similarity of precipitation and the similarity of flood, so that the future development situation of the flood is estimated, and the accuracy of estimation of the subsequent incoming water amount in the flood process is improved.
The technical scheme is as follows: on the first hand, a flood dynamic estimation method based on rainfall flood space-time process similarity excavation is provided, and the method comprises the following steps:
step 1, obtaining historical remote sensing inversion rainfall information, real-time remote sensing inversion rainfall information, numerical forecast rainfall information and historical stage flood information of a preset number of hydrologic stations in a research area, matching time scales of historical rainfall and flood information, and constructing a hydrologic station historical rainfall flood database;
step 2, aiming at the flood which is happening in the hydrological station, matching and splicing the space-time scales of early-stage remote sensing inversion precipitation before the flood rising time, observed remote sensing inversion precipitation from the flood rising time to the confrontation time and numerical forecast precipitation information after the confrontation time, calculating a surface average precipitation time sequence, and searching a historical precipitation process with similar surface average precipitation time sequence in the historical rainfall database established in the step 1 by adopting a time sequence similarity analysis method; screening historical rainfall processes similar to the spatio-temporal process by adopting a spatio-temporal information similarity analysis method, and extracting a corresponding similarity historical flood set 1;
step 3, searching a similarity historical flood set 2 with similar time sequence process in the historical rainfall flood database established in the step 1 by adopting a time sequence similarity analysis method according to flood information in an effective forecast period forecasted by the constantly observed flood and flood forecast model at the splicing face;
step 4, merging the similarity history flood sets 1 and 2 retrieved in the steps 2 and 3 to obtain a similarity history flood set 3, reasonably determining the splicing time point of each field of similar flood, calculating the average similar flood process after the splicing time point by adopting a weighted average method, and estimating the subsequent flood process through translation and splicing operation;
step 5, judging whether the follow-up flood process in the step 4 contains a flood peak or not, and stopping dynamic estimation if the follow-up flood process does not contain the flood peak; otherwise, updating the rainfall flood observation and forecast information along with the time, repeating the steps 2-4, and dynamically estimating the flood development situation.
In a further embodiment of the first aspect, the step 1 is further:
step 1-1, comprehensively performing remote sensing inversion on precipitation information and historical field flood information, reasonably determining time points and step lengths of field flood information at equal intervals, and acquiring flood data of sampling time points by adopting a cubic spline interpolation method;
step 1-2, judging whether the time step length of the historical remote sensing inversion precipitation information is consistent with the flood data or not; if the difference is not consistent, distributing the precipitation amount to a time period smaller than the time step of the flood information by an arithmetic mean method, and obtaining historical remote sensing inversion precipitation information matched with the time point and the time step of the flood data by accumulation;
step 1-3, intercepting corresponding historical rainfall spatio-temporal information from the historical remote sensing inversion rainfall information obtained in the step 1-2 according to the rising and ending time of each flood process, and recording the historical rainfall spatio-temporal information as the rainfall information in the flood period; before flood rising A1The early-stage rainfall information of each period is spliced with the rainfall information of the flood period to form complete rainfall information corresponding to the flood process; therefore, the rainfall and flood information of the field is stored by taking the flood occurrence date as a serial number, and a historical rainfall flood database is constructed.
In a further embodiment of the first aspect, the step 2 is further:
step 2-1, aiming at the occurring flood process, obtaining A consistent with the time point and the time step of the historical remote sensing inversion precipitation information by adopting the method of the step 1-21Early-stage remote sensing inversion rainfall information I of each period1、A2Remote sensing inversion rainfall information I observed in each time period2;
2-2, aiming at rainfall data forecasted in a nearest numerical mode before the moment, adjusting the spatial resolution of the forecast rainfall information to be consistent with the early-stage rainfall information and the observed rainfall information by methods such as bilinear interpolation, correcting errors by methods such as joint probability distribution, and processing by the method in the step 1-3 to obtain numerical forecast rainfall information with the same time step as that in the step 2-1; extracting A after face time3Individual time interval numerical forecast rainfall information I3(ii) a Splicing I1、I2And I3Obtaining the information P of observing and forecasting the rainfall at the momenttarget_stThe total number of time segments is A1+ A2+ A3;
Step 2-3, observing and forecasting rainfall information P of the facing moment with three-dimensional space-time attribute in the step 2-2target_stConversion into a time sequence P of mean precipitation of the surfacetarget_t(ii) a Calculating Ptarget_tAverage precipitation sequence P corresponding to each rain flood process in historical rain flood databasedatabase_tThe dynamic time of the method is used for regulating and sequencing DTW indexes, the smaller the DTW indexes are, the highest similarity is obtained, and the highest similarity is obtained in the screening time sequence process1Field dewatering;
in the formula: i and j are respectively Ptarget_tAnd Pdatabase_tIndex of a certain period in the information, d (P)target_t,i, Pdatabase_t,j) Is Ptarget_t,iAnd Pdatabase_t,jThe DTW index is substantially the minimum cumulative Euclidean distance from (1, 1) to (i, j),is the minimum cumulative euclidean distance traversed before point (i, j);
step 2-4, observing and forecasting rainfall information P at facing moment with three-dimensional space-time attributetarget_stTaking each grid in the plane space of the research area as an analysis unit, aiming at the grid (u, v) and at Ptarget_stCorresponding time range ST1Within, with tiIn time interval, the grid precipitation is centered at N × N × N time windows3The precipitation of each grid is used as a calculation monomer(N may be 3, 5, 7 …); for X1Remote sensing inversion of precipitation P in field precipitation processdatabase_stAt Pdatabase_stCorresponding time range ST2In the interior, the grid (u, v) and the t-th grid are extractedjComputing unit for same space-time range with time interval precipitation as center(ii) a Calculating the structural similarity index of two monomersThe index takes into account the integrated similarity of the mean, variance and covariance,the larger the value is, the higher the similarity of the space-time structures of the two is; transforming the index sequence number of the precipitation period and calculating the position of the grid (u, v)Comprehensive similarity index of space-time variation of precipitation in adjacent range;
Wherein:
in the formula: SSIM monomersAndregarding the images as two spatio-temporal images, the spatio-temporal images include L, C, S three parts, which respectively represent brightness, contrast and structure between the images, and α, β and γ are indexes of the three parts, and usually 1 is taken;、are respectively asMean and standard deviation of precipitation in the monomer;is a single bodyAndcovariance of internal precipitation; c. C1、c2、c3Is constant, avoids instability caused when the denominator is close to 0,wherein R is the difference between the maximum value and the minimum value of the precipitation in the monomer.
In the formula:is composed ofAndindex of structural similarityA function of, i.e.;Is composed ofMinimum accumulation of past dots;
Step 2-5, calculating the grid position in sequenceDrawing a DTW (SSIM) grid distribution diagram in the range of the research area; aiming at X searched in step 2-3 in sequence1In the field rain flood process, sequentially calculating to obtain a corresponding DTW (SSIM) grid distribution map; calculation face moment observation and forecast rainfall information Ptarget_stThe accumulated precipitation of each grid is sorted from big to small, the grid with the B% of the highest rank is selected, and the weight w of each selected grid is given according to the accumulated precipitationgridWeighted calculation DTW (SSIM) distribution diagram, and marked as DTW (SSIM) -SCORE; the smaller the DTW (SSIM) -SCORE is, the highest degree of temporal and spatial similarity of precipitation is, for X1Sorting DTW (SSIM) -SCORE in the field precipitation process from small to large, and selecting the top X2Taking the field precipitation as historical precipitation information with higher degree of similarity in the space-time process, and taking the corresponding flood process as a historical similarity flood set 1 based on precipitation space-time similarity retrieval;
in the formula: q is the number of grids ranked B% before the cumulative precipitation,in order to be a grid position,is a gridBy weight of (2), in a gridThe proportion of the precipitation quantity of the grid to the total precipitation quantity of the first q grids is calculated,。
in a further embodiment of the first aspect, the step 3 is further:
step 3-1, acupunctureFor historical rainfall flood information of the hydrological station, A is the time before the flood rises1Time period and flood rise to face time A2A between the average precipitation and flood rise of the research area of each period2Actual measurement flow (including facing time) at +1 time is used as BP neural network input data to forecast flood flow at v times in the future; taking the minimum of flood average (1-NSE) of the field times as an objective function, utilizing 70% of field times of rainfall flood information in a historical rainfall flood database, and calibrating the weight and the threshold of the BP neural network through a genetic algorithm, wherein the rest 30% of field times of rainfall flood information is used as test data of the precision of the BP neural network model; by gradually increasing the quantity v of the output flow of the BP neural network model, the average NSE of the test data is not lower than 0.70 (the second-level standard of the hydrological information forecasting specification (GB/T22482-2008)), so that the maximum v is determined, namely the effective forecasting period of flood forecasting;
in the formula:andare respectively the v thiThe current flow is measured according to the measured flow;the measured flow mean value is obtained; v is the total time of forecasting future flow.
Step 3-2, aiming at the flood process occurring in the hydrological station to face the moment A1+A2Area average observed precipitation sum A for each time period2Inputting the observed flow at +1 moments into the calibrated BP neural network model, and forecasting the flow Q of the hydrological station at v moments in the futureBPFlood forecasting is realized;
step 3-3, will face A before time2The observed flow at +1 time and the forecast flow at v times are spliced to generate a packetFlood time series f containing observed information and forecast informationtargetSequentially calculating each flood time sequence f in the historical rainfall flood databasedatabaseAnd ftargetThe DTW indexes of (1) are sorted from small to large, and the first X is taken3And (3) taking the field flood as a similarity history flood set 2 based on the similarity retrieval of the flood time sequence process.
In the formula: f. ofi,fjAre respectively ftargetAnd fdatabaseAn index of a time in the time series;is composed ofAndthe Euclidean distance between them;is (f)i,fj) The minimum cumulative euclidean distance traveled before the point.
In a further embodiment of the first aspect, the step 4 is further:
step 4-1, merging the similarity historical flood set 1 based on rainfall space-time similarity retrieval and the similarity historical flood set 2 based on flood time sequence process similarity retrieval to obtain X2+X3The historical flood process that the field is similar to the flood is recorded as a similarity historical flood set 3;
step 4-2, recording ftargetLength of (L), sliding computation of different starting points and times (I) of a flood process in the similarity historical flood set 30To the following item I0Flood sequence f between + L-1 momentsdatabase_partAnd ftargetTaking the sum of squared deviations ofMinimum corresponding item I0,bestThe + L-1 moments are used as splicing positions of the similar flood and the flood in the field; respectively determining a splicing position aiming at each flood in the similarity historical flood set 3, and after the splicing positions are weighted and calculated by adopting an equal weight method, X2+X3Average similar flood process f of field similar flood processessimilarity,fsimilarityLength and X of2+X3The lengths of the shortest flood time sequences after the splicing positions in the field similar flood process are consistent and are recorded as Lsimilarity;
In the formula:representing the flow of the Kth field similar flood sequence in the similarity historical flood set 3 at the ith moment after the splicing position;
step 4-3, beyond the effective forecasting period of flood forecasting, the flood forecasting cannot provide reliable forecasting flow, and the average similar flood process fsimilarityMove up and downAnd splicing the prediction flow with the forecast flow at v moments after the confrontation moment to obtain a complete flood prediction result after the confrontation moment, namely:
in the formula: t is t0Dynamically estimating the confrontation moment for the flood; flood process estimation result based on similar excavation of rainfall flood space-time process;The estimation results are for the complete flood process after the moment is encountered.
In a further embodiment of the first aspect, the process of step 5 further comprises:
step 5-1, judging flood process estimation results based on precipitation and flood similarityWhether flood peak information is contained or not is judged, if yes, the dynamic estimation stopping condition is not met, otherwise, if no flood peak information is contained, namely, all the flood peak information is in the process of water withdrawal, the dynamic estimation is stopped;
step 5-2, if the stopping condition is not met, moving to the next facing moment along with time, updating rainfall observation and forecast information and flood observation and forecast information in the effective forecast period, repeating the step 2-4, and realizing the flood process forecast result based on rainfall and flood similarityIs dynamically updated.
In a further embodiment of the first aspect, the steps 1 to 5 are repeated to obtain a dynamic estimation result of the flood process of the hydrological station in the research area.
In a second aspect, a flood dynamic estimation system based on similarity of rain flood space-time processes is provided, the system comprising:
the system comprises a first module, a second module and a third module, wherein the first module is used for acquiring historical remote sensing inversion rainfall information, real-time remote sensing inversion rainfall information, numerical forecast rainfall information and historical site flood information of a preset number of hydrologic stations in a research area, matching the time scales of historical rainfall and flood information and constructing a hydrologic station historical rainfall flood database;
the second module is used for matching and splicing the space-time scales of the remote sensing inversion precipitation and numerical forecast precipitation information facing the earlier stage of time and observed aiming at the flood which is happening in the hydrological station, and searching historical precipitation processes with similar surface average precipitation time sequences in a historical rainfall flood database established by the first module by adopting a time sequence similarity analysis method; screening historical rainfall processes similar to the spatio-temporal process by adopting a spatio-temporal information similarity analysis method, and extracting a corresponding similarity historical flood set 1;
the third module is used for splicing flood information in an effective forecast period of constantly observed flood and flood forecast model forecast, and searching a historical flood process set 2 with similar time sequence processes in a historical rainfall flood database by adopting a time sequence similarity analysis method;
the fourth module is used for merging the historical flood process sets 1 and 2 to obtain a similar historical flood process set 3, reasonably determining the splicing time point of similar floods in each field, calculating the average similar flood process after the splicing time point by adopting a weighted average method, and estimating the subsequent flood process through translation and splicing operation;
the fifth module judges whether the follow-up flood process estimated by the fourth module contains a flood peak or not, and stops dynamic estimation if the follow-up flood process does not contain the flood peak; otherwise, updating the rainfall flood observation and forecast information along with the time, repeatedly executing the second module to the fourth module, and dynamically estimating the development situation of the flood.
Has the advantages that: the method mainly comprises the steps of historical rainfall flood database construction, historical flood process retrieval based on rainfall spatio-temporal process similarity, historical flood process retrieval based on flood time sequence process similarity and dynamic prediction based on historical similar flood. In the historical rainfall flood database construction stage, long-series historical remote sensing is used for inverting precipitation information, and three-dimensional space-time precipitation processes corresponding to the historical flood processes are extracted, so that a historical rainfall flood event library reflecting the space-time evolution process is constructed. In a historical flood process retrieval stage based on rainfall space-time process similarity, rainfall information and numerical forecast rainfall information are inverted by coupling the early stage and observed remote sensing, on the basis of only considering the similarity of a surface average rainfall time sequence in the prior art, a coupling structure similarity index SSIM and a DTW (SSIM) index of dynamic time warping DTW are provided, the space-time similarity of the historical rainfall process and the observation and forecast rainfall process is measured, and therefore the influence of rainfall falling area distribution on the flood process is considered. In the historical flood process retrieval stage based on the similarity of the flood time sequence process, the observed flow information and the effective forecast period flow information forecasted by the flood model are utilized in a coupling mode, so that reliable information is added in the similarity analysis of the flood time sequence process, and the retrieval result of the historical flood process with the similarity is improved. In a dynamic estimation stage based on historical similar flood, the historical similar flood which considers the occurrence and development processes of the rainfall flood more comprehensively can be obtained by integrating retrieval results of rainfall spatio-temporal similarity and flood time sequence similarity, and the flood estimation precision is gradually improved along with the time lapse and the rainfall flood information accumulation and update. Generally, the method comprehensively utilizes historical, real-time observed and forecasted rainfall and flood information in the aspect of information, achieves the expansion from a one-dimensional time sequence to a three-dimensional space-time process in the aspect of similarity analysis dimensionality, provides a quantitative measurement method of space-time process similarity in the aspect of a mathematical method, and can powerfully promote the development of a flood dynamic prediction technology based on the rain flood process similarity mining.
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Fig. 1 is a flowchart of a first embodiment of the present invention.
Fig. 2 shows a reservoir control catchment area of a third watershed a according to an embodiment of the invention.
Detailed Description
In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without one or more of these specific details. In other instances, well-known features have not been described in order to avoid obscuring the invention.
The first embodiment is as follows:
a flood dynamic estimation method based on rainfall flood space-time process similarity excavation comprises the following steps:
acquiring historical remote sensing retrieval rainfall information, real-time remote sensing retrieval rainfall information, numerical forecast rainfall information and historical site flood information of a preset number of hydrological stations in a research area, matching time scales of historical rainfall and flood information, and constructing a hydrological station historical rainfall flood database; aiming at the flood which is happening in a hydrological station, matching and splicing the space-time scales of the early stage of the moment and the observed remote sensing inversion precipitation and numerical forecast precipitation information, and searching a historical precipitation process with similar surface average precipitation time sequence in a historical rainfall flood database by adopting a dynamic time warping DTW index; further screening historical precipitation processes similar to the time-space process by adopting a coupling Structure Similarity Index (SSIM) and a Dynamic Time Warping (DTW) index, and extracting a corresponding historical flood process set 1; the method comprises the steps that flood information in an effective forecast period forecasted by a flood forecast model and observed floods at the moment are spliced, and a historical flood process set 2 with similar time sequence processes is searched in a historical rainfall flood database by adopting a DTW index; merging the historical flood process sets 1 and 2 to obtain a similar historical flood process set 3, reasonably determining the splicing time point of each field of similar flood, calculating the average similar flood process after the splicing time point by adopting an equal weight weighted average method, and pre-estimating the subsequent flood process through translation and splicing operation; and judging whether the current estimated follow-up flood process at the moment contains a flood peak or not, if not, stopping dynamic estimation, otherwise, updating rainfall flood observation and forecast information along with the time, and dynamically estimating the flood development situation.
Example two:
on the basis of the first embodiment, the second embodiment further provides a refinement step of a flood dynamic estimation method based on the rainfall flood space-time process similarity mining, which comprises the following steps:
step 1, obtaining historical remote sensing inversion rainfall information, real-time remote sensing inversion rainfall information, numerical forecast rainfall information and historical stage flood information of a preset number of hydrologic stations in a research area, matching time scales of historical rainfall and flood information, and constructing a hydrologic station historical rainfall flood database;
step 1-1, acquiring historical and real-time remote sensing inversion observation rainfall information, numerical forecast rainfall information and historical field flood information of a research area;
step 1-2, comprehensively performing remote sensing inversion on precipitation information and historical field flood information, reasonably determining time points and step lengths of field flood information at equal intervals, and acquiring flood data of sampling time points by adopting a cubic spline interpolation method;
step 1-3, judging whether the time step length of the historical remote sensing inversion precipitation information is consistent with the flood data or not; if the difference is not consistent, distributing the precipitation amount to a time period smaller than the time step of the flood information by an arithmetic mean method, and obtaining historical remote sensing inversion precipitation information matched with the time point and the time step of the flood data by accumulation;
step 1-4, intercepting corresponding historical rainfall spatio-temporal information from the historical remote sensing inversion rainfall information obtained in the step 1-3 according to the rising and ending time of each flood process, and recording the historical rainfall spatio-temporal information as the rainfall information in the flood period; before flood rising A1The early-stage rainfall information of each period is spliced with the rainfall information of the flood period to form complete rainfall information corresponding to the flood process; therefore, the rainfall and flood information of the field is stored by taking the flood occurrence date as a serial number, and a historical rainfall flood database is constructed.
Step 2, aiming at the flood which is happening in the hydrological station, matching and splicing the space-time scales of early-stage remote sensing inversion precipitation before the flood rising time, observed remote sensing inversion precipitation from the flood rising time to the confrontation time and numerical forecast precipitation information after the confrontation time, calculating a surface average precipitation time sequence, and searching a historical precipitation process with similar surface average precipitation time sequence in the historical rainfall database established in the step 1 by adopting a time sequence similarity analysis method; screening historical rainfall processes similar to the spatio-temporal process by adopting a spatio-temporal information similarity analysis method, and extracting a corresponding similarity historical flood set 1;
step 2-1, aiming at the occurring flood process, obtaining A consistent with the time point and the time step of the historical remote sensing inversion precipitation information by adopting the method of the step 1-21Individual period early stage remote sensing inversion precipitation information I1、A2Remote sensing inversion rainfall information I observed in each time period2;
Step 2-2, aiming at rainfall data forecasted in a nearest numerical mode before the moment, adjusting the spatial resolution of the forecast rainfall information to be consistent with the early-stage rainfall information and the observed rainfall information by methods such as bilinear interpolation, correcting errors by methods such as joint probability distribution, processing by the method in step 1-3 to obtain numerical forecast rainfall with the same time step as that in step 2-1Water information; extracting A after face time3Individual time interval numerical forecast rainfall information I3(ii) a Splicing I1、I2And I3Obtaining the information P of observing and forecasting the rainfall at the momenttarget_stThe total number of time segments is A1+ A2+ A3;
Step 2-3, observing and forecasting rainfall information P of the facing moment with three-dimensional space-time attribute in the step 2-2target_stConversion into a time sequence P of mean precipitation of the surfacetarget_t(ii) a Calculating Ptarget_tAverage precipitation sequence P corresponding to each rain flood process in historical rain flood databasedatabase_tThe dynamic time of the method is used for regulating and sequencing DTW indexes, the smaller the DTW indexes are, the highest similarity is obtained, and the highest similarity is obtained in the screening time sequence process1Field dewatering;
in the formula: i and j are respectively Ptarget_tAnd Pdatabase_tIndex of a certain period in the information, d (P)target_t,i, Pdatabase_t,j) Is Ptarget_t,iAnd Pdatabase_t,jThe DTW index is substantially the minimum cumulative Euclidean distance from (1, 1) to (i, j),is the minimum cumulative euclidean distance traversed before point (i, j);
step 2-4, observing and forecasting rainfall information P at facing moment with three-dimensional space-time attributetarget_stTaking each grid in the plane space of the research area as an analysis unit, aiming at the grid (u, v) and at Ptarget_stCorresponding time range ST1Within, with tiIn time interval, the grid precipitation is centered at N × N × N time windows3The precipitation of each grid is used as a calculation monomer(N may be 3, 5, 7 …); for X1Remote sensing inversion of precipitation P in field precipitation processdatabase_stAt Pdatabase_stCorresponding time range ST2In the interior, the grid (u, v) and the t-th grid are extractedjComputing unit for same space-time range with time interval precipitation as center(ii) a Calculating the structural similarity index of two monomersThe index considers the comprehensive similarity of the mean value, the variance and the covariance, and the larger the value is, the higher the similarity of the space-time structures of the mean value, the variance and the covariance is; transforming the index sequence number of the precipitation time interval, and calculating the comprehensive similarity index of the precipitation space-time change in the adjacent range at the grid (u, v) position;
Wherein:
in the formula: SSIM monomersAndregarding the images as two spatio-temporal images, the spatio-temporal images include L, C, S three parts, which respectively represent brightness, contrast and structure between the images, and α, β and γ are indexes of the three parts, and usually 1 is taken;、are respectively asMean and standard deviation of precipitation in the monomer;is a single bodyAndcovariance of internal precipitation; c. C1、c2、c3Is constant, avoids instability caused when the denominator is close to 0,wherein R is the difference between the maximum value and the minimum value of the precipitation in the monomer.
In the formula:is composed ofAndindex of structural similarityA function of, i.e.;Is composed ofMinimum accumulation of past dots;
Step 2-5, calculating the grid position in sequenceDrawing a DTW (SSIM) grid distribution diagram in the range of the research area; aiming at X searched in step 2-3 in sequence1In the field rain flood process, sequentially calculating to obtain a corresponding DTW (SSIM) grid distribution map; calculation face moment observation and forecast rainfall information Ptarget_stThe accumulated precipitation of each grid is sorted from big to small, the grid with the B% of the highest rank is selected, and the weight w of each selected grid is given according to the accumulated precipitationgridWeighted calculation DTW (SSIM) distribution diagram, and marked as DTW (SSIM) -SCORE; the smaller the DTW (SSIM) -SCORE is, the highest degree of temporal and spatial similarity of precipitation is, for X1Sorting DTW (SSIM) -SCORE in the field precipitation process from small to large, and selecting the top X2Taking the field precipitation as historical precipitation information with higher degree of similarity in the space-time process, and taking the corresponding flood process as a historical similarity flood set 1 based on precipitation space-time similarity retrieval;
in the formula: q is the number of grids ranked B% before the cumulative precipitation,in order to be a grid position,is a gridBy weight of (2), in a gridThe proportion of the precipitation quantity of the grid to the total precipitation quantity of the first q grids is calculated,。
step 3, searching a similarity historical flood set 2 with similar time sequence process in the historical rainfall flood database established in the step 1 by adopting a time sequence similarity analysis method according to flood information in an effective forecast period forecasted by the constantly observed flood and flood forecast model at the splicing face;
step 3-1, aiming at historical rainfall flood information of the hydrological station, raising flood to a height A1Time period and flood rise to face time A2A between the average precipitation and flood rise of the research area of each period2Actual measurement flow (including facing time) at +1 time is used as BP neural network input data to forecast flood flow at v times in the future; taking the minimum of flood average (1-NSE) of the field times as an objective function, utilizing 70% of field times of rainfall flood information in a historical rainfall flood database, and calibrating the weight and the threshold of the BP neural network through a genetic algorithm, wherein the rest 30% of field times of rainfall flood information is used as test data of the precision of the BP neural network model; by gradually increasing the quantity v of the output flow of the BP neural network model, the average NSE of the test data is not lower than 0.70 (the second-level standard of the hydrological information forecasting specification (GB/T22482-2008)), so that the maximum v is determined, namely the effective forecasting period of flood forecasting;
in the formula: andare respectively the v thiThe current flow is measured according to the measured flow;the measured flow mean value is obtained; v is the total time of forecasting future flow.
Step 3-2, aiming at the flood process occurring in the hydrological station to face the moment A1+A2Area average observed precipitation sum A for each time period2Inputting the observed flow at +1 moments into the calibrated BP neural network model, and forecasting the flow Q of the hydrological station at v moments in the futureBPFlood forecasting is realized;
step 3-3, will face A before time2Splicing the observed flow at +1 moments and the forecast flow at v moments to generate a flood time sequence f containing observed information and forecast informationtargetSequentially calculating each flood time sequence f in the historical rainfall flood databasedatabaseAnd ftargetThe DTW indexes of (1) are sorted from small to large, and the first X is taken3And (3) taking the field flood as a similarity history flood set 2 based on the similarity retrieval of the flood time sequence process.
In the formula: f. ofi,fjAre respectively ftargetAnd fdatabaseAn index of a time in the time series;is composed ofAndthe Euclidean distance between them;is (f)i,fj) The minimum cumulative euclidean distance traveled before the point.
Step 4, merging the similarity history flood sets 1 and 2 retrieved in the steps 2 and 3 to obtain a similarity history flood set 3, reasonably determining the splicing time point of each field of similar flood, calculating the average similar flood process after the splicing time point by adopting a weighted average method, and estimating the subsequent flood process through translation and splicing operation;
step 4-1, merging the similarity historical flood set 1 based on rainfall space-time similarity retrieval and the similarity historical flood set 2 based on flood time sequence process similarity retrieval to obtain X2+X3The historical flood process that the field is similar to the flood is recorded as a similarity historical flood set 3;
step 4-2, recording ftargetLength of (L), sliding computation of different starting points and times (I) of a flood process in the similarity historical flood set 30To the following item I0Flood sequence f between + L-1 momentsdatabase_partAnd ftargetSum of squared deviations ofGet itMinimum corresponding item I0,bestThe + L-1 moments are used as splicing positions of the similar flood and the flood in the field; respectively determining a splicing position aiming at each flood in the similarity historical flood set 3, and after the splicing positions are weighted and calculated by adopting an equal weight method, X2+X3Average similar flood process f of field similar flood processessimilarity,fsimilarityLength and X of2+X3The lengths of the shortest flood time sequences after the splicing positions in the field similar flood process are consistent and are recorded as Lsimilarity;
In the formula:representing the flow of the Kth field similar flood sequence in the similarity historical flood set 3 at the ith moment after the splicing position;
step 4-3, beyond the effective forecasting period of flood forecasting, the flood forecasting cannot provide reliable forecasting flow, and the average similar flood process fsimilarityMove up and downAnd splicing the prediction flow with the forecast flow at v moments after the confrontation moment to obtain a complete flood prediction result after the confrontation moment, namely:
in the formula: t is t0Dynamically estimating the confrontation moment for the flood; estimating a flood process estimation result based on similar excavation of the rainfall flood space-time process;the estimation results are for the complete flood process after the moment is encountered.
Step 5, judging whether the follow-up flood process in the step 4 contains a flood peak or not, and stopping dynamic estimation if the follow-up flood process does not contain the flood peak; otherwise, updating the rainfall flood observation and forecast information along with the time, repeating the steps 2-4, and dynamically estimating the flood development situation.
Step 5-1, judging flood process estimation results based on precipitation and flood similarityIf the flood peak information is contained, the dynamic estimation stopping condition is not met, otherwise, if the flood peak information is not contained, all the steps are the water returning process,stopping dynamic estimation;
step 5-2, if the stopping condition is not met, moving to the next facing moment along with time, updating rainfall observation and forecast information and flood observation and forecast information in the effective forecast period, repeating the step 2-4, and realizing the flood process forecast result based on rainfall and flood similarityIs dynamically updated.
Example three:
in this embodiment, a reservoir in a certain watershed a is taken as a research object, and fig. 2 is a water collection area for controlling the reservoir in the certain watershed a according to the embodiment of the invention. A flood dynamic estimation method based on rainfall flood space-time process similarity excavation is provided. The main stream flows through 2 provinces in Shaanxi and Hubei of Changjiang river, and converges to Yangtze river in Wuhan, with the total length of 1577 km. The range of the drainage basin is between 106 DEG 15 'E and 114 DEG 20' E and 30 DEG 10 'N and 34 DEG 20' N, and the total area is about 15.9 km2. The drainage basin is complex in terrain, is high in the west and low in the east, belongs to a monsoon climate area in the east subtropical zone, has average rainfall of about 900mm for many years, is uneven in rainfall spatial-temporal distribution, has a distribution rule that annual rainfall shows that a south bank is larger than a north bank, the upstream and the downstream are large, and the midstream is small, and 70-80% of rainfall in the whole year is concentrated in a flood season (5-10 months).
In the embodiment, Multi-Source Weighted-Ensemble Precipitation version 2.1 (MSWEP V2.1) long-series remote sensing inversion Precipitation data (time Range: 1979-2016, time resolution: 3h, UTC time; spatial resolution: 0.1 degree) and control forecast Precipitation information of ECMWF (European Centre for Medium-Range Weather forms) mode (time Range: 2008-2016, time resolution: 6h, forecast period: 10 days, UTC time, UTC00:00 update every day, spatial resolution: 0.5 degree), and 58-field flood data of A reservoir between 1979 and 2010 (time resolution 6h, North time 08:00, 14:00, 20:00, 02: 00) are collected. Forecast precipitation data only include two floods, namely 20100716 floods and 20100722 floods, between 2008 and 2010, in the embodiment, a historical rainfall flood database is constructed by the rest 56 floods and corresponding MSWEP V2.1 precipitation information, two warehouse-in floods in 2010 are selected as estimation samples, and a dynamic flood estimation method based on similarity mining of a rainfall flood space-time process is applied, and the method mainly comprises the following steps:
s1): constructing a historical rainfall flood database: and (3) integrating the time and the spatial resolution of the MSWEP V2.1 inversion precipitation, ECMWF forecast precipitation data and flood data, and determining that the time of the rainfall flood is uniformly adjusted to be Beijing time, the time points are 02:00, 08:00, 14:00 and 20:00 respectively, the time step length is 6h, and the spatial resolution of the rainfall is 0.5 degrees multiplied by 0.5 degrees. In the aspect of time, the MSWEP V2.1 data are accumulated to obtain precipitation data with the step length of 6h, the time mark is increased by 8h (the difference between the Beijing time and the UTC time is 8 h) to obtain the MSWEP V2.1 precipitation data of four time periods of 02: 00-08: 00, 08: 00-14: 00, 14: 00-20: 00 and 20: 00-02: 00 every day at the Beijing time, and the time point of the flood data is consistent with the target time; spatially, a bilinear interpolation method is used to scale up a 0.1 ° × 0.1 ° MSWEP V2.1 to 0.5 ° × 0.5 °. The method comprises the steps of extracting rainfall corresponding to historical flood from long-series MSWEP V2.1 data, intercepting MSWEP V2.1 within 3 days (12 time periods) before the flood rises and within the time range from the flood rise to the flood end in terms of time, performing mask processing on global MSWEP V2.1 data by adopting an A reservoir control water collection area boundary file in terms of space, and extracting MSWEP V2.1 rainfall space-time data of a research area range corresponding to each historical flood. And matching the field MSWEP V2.1 precipitation and flood data, and storing the rainfall flood data by taking the flood rising date as a serial number, thereby constructing a historical rainfall flood database of the reservoir A.
S2): searching historical flood processes based on precipitation space-time process similarity: aiming at the occurring flood process, because the ECMWF forecast precipitation information is updated at the time 08:00 of Beijing every day (UTC 00: 00), the facing moment of flood dynamic estimation is taken as the time 08:00 of Beijing every day. At the moment of facing, extracting MSWEP V2.1 data which are within the range of the research area, have the same time point and time step length as the historical database, are 3 days before the flood rises and rise to the moment of facing by adopting the same method as the step S1), and recording the data as early stage and observed precipitation MP; for the ECMWF control forecast rainfall data which is most adjacent to the moment, increasing the time mark by 8h, converting the data into Beijing time, correcting the ECMWF control forecast rainfall by adopting a joint probability distribution method, intercepting forecast rainfall data 8 time intervals (2 days) after the moment and recording the data as forecast rainfall PP; and splicing the MP and the PP according to time to form the MPP _ ST which has three-dimensional space-time attributes and faces the earlier stage of time, is observed and forecasts precipitation. And (3) converting the MPP into a surface average precipitation time sequence MPP _ T by adopting an equal weight weighting method, sequentially evaluating the time sequence similarity degree of the MPP _ T and each precipitation process in a historical rainfall flood database by adopting a DTW index, and selecting the precipitation process with the 6 surface average time sequence process with the minimum DTW index. On the basis, the DTW (SSIM) distribution diagram of the 6 similar precipitation processes is calculated in a sliding mode by utilizing a 3X 3 space-time window. Calculating the accumulated precipitation amount of each grid of MPP _ ST data, selecting q grids of the first 30% from large to small as main precipitation falling areas, weighting and calculating the DTW (SSIM) -SCORE of a DTW (SSIM) distribution diagram of 6-field similar precipitation processes by taking the proportion of the accumulated precipitation amount of each grid in the total precipitation amount of q grids as weight, taking the first 3 fields as space-time similar precipitation processes after sorting from small to large, and taking the corresponding flood process as a similarity historical flood set 1 based on precipitation space-time similar retrieval.
S3): and (3) searching historical flood processes based on similarity of flood time sequence processes: a BP neural network is adopted as a flood forecasting model, the average precipitation of a 3-day (12 periods) face in the early period of the facing moment and the corresponding facing moment flow (1 moment) are used as the input of the BP neural network, the effective forecasting period is tested by gradually increasing the number of output flow data, and finally the average NSE is determined to be not lower than 0.70 when the model outputs flood information at 2 moments in the future. And splicing the Flood rising to the Flood facing moment observation information and the Flood information predicted by the BP model at the future 2 moments, and recording as the Flood facing moment observation and Flood forecasting information Flood _ T. And sequentially evaluating the time sequence similarity degree of the Flood _ T and each Flood process in the historical rainfall Flood database by adopting the DTW indexes, and selecting the Flood process with the 3 fields with the minimum DTW indexes and similar time sequence process as a similarity historical Flood set 2 based on Flood time sequence similarity retrieval.
S4): estimating the flood development situation based on historical similar flood: and merging the similarity history flood sets 1 and 2 to form a similarity history flood set 3, determining the splicing position of each similarity history flood process by adopting a mode of sliding calculation of least sum of squared deviations, calculating an average similar flood process after the splicing position by adopting an equal weight weighting method, and splicing the average similar flood process with the flow predicted by the BP neural network model by vertically translating the average similar flood process to realize the prediction of the flood development situation.
S5): flood dynamic estimation and termination condition judgment: if the average similar flood process in the S4) contains flood peak information, the stopping condition is not met, and the steps S2) -S5) are repeated; otherwise, if only the flood water-dropping process is involved, the dynamic estimation is stopped.
S6): estimating the accuracy of the subsequent water inflow of the flood: the flood estimation precision is measured by RBIAS facing the relative error between the subsequent incoming water volume of the estimated flood and the actually measured flood at any moment, and the calculation formula is as follows:
s7): in order to analyze the effectiveness of the method, the third embodiment compares the method with two traditional methods of flood dynamic estimation, namely the traditional method considering that the average observed precipitation of the surface is similar to the forecast precipitation. It should be noted that the difference between the two traditional methods and the method of the present invention is only in the precipitation similarity retrieval part, and the flood similarity retrieval part is consistent.
Table 1 shows the prediction accuracy of the BP neural network model for the flow at the 1 st and 2 nd time points in the future. According to the method, 70% of rainfall flood information of a field in a historical rainfall flood database is used as training data, a Nash efficiency coefficient NSE average value is used as a target function, a genetic algorithm is adopted to calibrate model parameters, and 30% of rainfall flood information of the field is used as a verification set. The average flood forecast NSE of the training set and the validation set at the time 2 is higher than 0.70. The BP neural network model has higher forecasting precision on No. 20100716 flood and No. 20100722 flood.
TABLE 1 prediction accuracy of BP neural network model for future 1 st and 2 nd moment flows
Forecast time period | Training set | Verification set | 20100716NSE | 20100722 NSE |
1st | 90% | 85% | 90% | 89% |
2nd | 87% | 82% | 90% | 87% |
Table 2 shows the flood dynamic estimation method based on the similarity mining of the rainfall flood space-time process and the traditional method for estimating the subsequent water inflow amount of the flood and the relative error thereof. The estimation precision of the two traditional methods for the subsequent inflow amount of the two-field flood is superior to that of the method only in the 1 st dynamic estimation; although the post-estimation water volume of 20100716 flood is closer to the actual measurement flood in the 4 th dynamic estimation, the actual result is due to the overestimation of the water withdrawal process, and the control of the flood process, the flood peak and the flood volume is not good. Generally, in a dynamic estimation test, rainfall and flood observation information gradually accumulates along with the lapse of the faced moment, the relative error of the estimated subsequent water inflow tends to be reduced by the method, and the traditional method does not show the trend of increasing estimation precision and has unstable performance. Therefore, the method effectively exerts the advantages of observation and forecast information coupling utilization and similarity analysis dimension expansion, and except for the 1 st rolling forecast and the 4 th rolling forecast, the relative error of the estimated subsequent water inflow is relatively reduced by 9.7-38.5% compared with that of the traditional method.
TABLE 2 flood dynamic estimation method based on similarity excavation of rainfall flood time-space process and traditional method for estimating subsequent water inflow amount of flood and relative error thereof
By adopting the technical scheme disclosed by the invention, the following beneficial effects are obtained: the flood dynamic estimation method based on the rainfall and flood space-time process similarity excavation coupling utilizes observation and forecast rainfall and flood information, measures rainfall and flood space-time process similarity by adopting a coupling structure similarity index SSIM and a DTW (SSIM) index of dynamic time warping DTW, realizes the expansion of rainfall and flood process similarity analysis from a one-dimensional time sequence to a three-dimensional space-time process, more comprehensively considers the occurrence and evolution processes of flood, improves the retrieval effect of similar flood, and estimates the accuracy of the subsequent water volume of flood to be higher than that of the traditional method utilizing the surface average rainfall information.
In the aspect of information utilization, the embodiment mainly relates to remote sensing precipitation MSWEP V2.1 and numerical forecast precipitation ECMWF. In the aspect of using a flood forecasting model, the method mainly relates to a BP neural network model. It should be noted that the method has strong expansibility, and other remote sensing inversion, atmosphere reanalysis, numerical forecast precipitation information and flood forecast models can be used for the method.
As noted above, while the present invention has been shown and described with reference to certain preferred embodiments, it is not to be construed as limited thereto. Various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (8)
1. A flood dynamic estimation method based on similarity excavation of a rainfall flood space-time process is characterized by comprising the following steps:
step 1, obtaining historical remote sensing inversion rainfall information, real-time remote sensing inversion rainfall information, numerical forecast rainfall information and historical stage flood information of a preset number of hydrologic stations in a research area, matching time scales of historical rainfall and flood information, and constructing a hydrologic station historical rainfall flood database;
step 2, aiming at the flood which is happening in the hydrological station, matching and splicing the space-time scales of early-stage remote sensing inversion precipitation before the flood rising time, observed remote sensing inversion precipitation from the flood rising time to the confrontation time and numerical forecast precipitation information after the confrontation time, calculating a surface average precipitation time sequence, and searching a historical precipitation process with similar surface average precipitation time sequence in the historical rainfall database established in the step 1 by adopting a time sequence similarity analysis method; screening historical rainfall processes similar to the spatio-temporal process by adopting a spatio-temporal information similarity analysis method, and extracting a corresponding similarity historical flood set 1;
step 3, searching a similarity historical flood set 2 with similar time sequence process in the historical rainfall flood database established in the step 1 by adopting a time sequence similarity analysis method according to flood information in an effective forecast period forecasted by the constantly observed flood and flood forecast model at the splicing face;
step 4, merging the similarity historical flood set 1 and the similarity historical flood set 2 retrieved in the steps 2 and 3 to obtain a similarity historical flood set 3, determining the splicing time point of each field of similar flood, calculating the average similar flood process after the splicing time point by adopting a weighted average method, and pre-estimating the subsequent flood process through translation and splicing operation;
step 5, judging whether the follow-up flood process in the step 4 contains a flood peak or not, and stopping dynamic estimation if the follow-up flood process does not contain the flood peak; otherwise, updating the rainfall flood observation and forecast information along with the time, repeating the steps 2-4, and dynamically estimating the flood development situation.
2. The flood dynamic estimation method based on the rainfall flood space-time process similarity mining according to claim 1, wherein the step 1 further comprises:
step 1-1, comprehensively performing remote sensing inversion on precipitation information and historical field flood information, determining time points and step lengths of field flood information at equal intervals, and acquiring flood data of sampling time points by adopting a cubic spline interpolation method;
step 1-2, judging whether the time step of the historical remote sensing inversion precipitation information is consistent with the flood data or not; if the difference is not consistent, distributing the precipitation amount to a time period smaller than the time step of the flood information by an arithmetic mean method, and obtaining historical remote sensing inversion precipitation information matched with the time point and the time step of the flood data by accumulation;
step 1-3, intercepting corresponding historical rainfall spatio-temporal information from the historical remote sensing inversion rainfall information obtained in the step 1-2 according to the rising and ending time of each flood process, and recording the historical rainfall spatio-temporal information as the rainfall information in the flood period; before flood rising A1The early-stage rainfall information of each period is spliced with the rainfall information of the flood period to form complete rainfall information corresponding to the flood process; therefore, the rainfall and flood information of the field is stored by taking the flood occurrence date as a serial number, and a historical rainfall flood database is constructed.
3. The flood dynamic estimation method based on the rainfall flood space-time process similarity mining according to claim 1, wherein the step 2 further comprises:
step 2-1, aiming at the occurring flood process, obtaining A consistent with the rainfall time point and the time step of the historical remote sensing inversion by adopting the method of the step 1-21Individual period early stage remote sensing inversion precipitation information I1、A2Remote sensing inversion rainfall information I observed in each time period2;
Step 2-2, acquiring precipitation data of the nearest numerical model forecast before the confrontation moment, matching the spatio-temporal scale and correcting errors, and intercepting A after the confrontation moment3Number of time periodForecast precipitation information I3(ii) a Splicing I1、I2And I3Obtaining the information P of observing and forecasting the rainfall at the momenttarget_st;
Step 2-3, adding Ptarget_stConversion into a time sequence P of mean precipitation of the surfacetarget_t(ii) a Calculating Ptarget_tAverage precipitation sequence P corresponding to each rain flood process in historical rain flood databasedatabase_tThe DTW indexes are normalized and sorted according to the dynamic time, and the front X with the highest similarity degree in the time sequence process is screened1Field dewatering;
step 2-4 for Ptarget_stAnd X1Remote sensing inversion of precipitation P in field precipitation processdatabase_stFor spatial positions (u, v), respectively, by ti、tjTwo time periods of grid precipitation are taken as centers, and the surrounding N multiplied by N grid precipitation are used for constructing the mobile unitsAndcalculating the structural similarity index of the two(ii) a Moving along the time axis, willEmbedding DTW formula, calculating positionSpace-time similarity index of(ii) a Thus, for X in step 2-31In the field precipitation process, SSIM grid distribution maps in the range of the research area are drawn one by one;
in the formula:is a single bodyAndindex of structural similarityA function of, i.e.;Is composed ofMinimum accumulation of past dots;
Step 2-5, calculating Ptarget_stCumulative precipitation at each grid location and weighting w according to precipitation sizegridWeighting and calculating the average score of the SSIM distribution diagram, and selecting the front X with the minimum average score2Precipitation on the ground, corresponding to the flood process as a search based on the spatio-temporal similarity of precipitationSimilarity historical flood set 1.
4. The flood dynamic estimation method based on the rainfall flood space-time process similarity mining according to claim 1, wherein the step 3 further comprises:
step 3-1, aiming at historical rainfall flood information of the hydrological station, raising flood to a height A1Time period and flood rise to face time A2A between the average precipitation and flood rise of the research area of each period2Actual measurement flow at +1 moments is used as BP neural network input data to forecast flood flow at v moments in the future; taking the field flood average 1-NSE minimum as an objective function, and calibrating the weight and the threshold of the BP neural network through a genetic algorithm; the average NSE of the test data is not lower than a preset standard by gradually increasing the quantity v of the output flow of the BP neural network model, so that the maximum v is determined, namely the effective forecast period of the flood forecast;
step 3-2, aiming at the flood process occurring in the hydrological station to face the moment A1+A2Area average observed precipitation sum A for each time period2Inputting the observed flow at +1 moments into the calibrated BP neural network model, and forecasting the flow Q of the hydrological station at v moments in the futureBPFlood forecasting is realized;
step 3-3, will face A before time2Splicing the observed flow at +1 moments and the forecast flow at v moments to generate a flood time sequence f containing observed information and forecast informationtargetSequentially calculating each flood time sequence f in the historical rainfall flood databasedatabaseAnd ftargetThe DTW indexes of (1) are sorted from small to large, and the first X is taken3And (3) taking the field flood as a similarity history flood set 2 based on the similarity retrieval of the flood time sequence process.
5. The flood dynamic estimation method based on the rainfall flood space-time process similarity mining according to claim 1, wherein the step 4 further comprises:
step 4-1, merging similarity calendars based on rainfall spatio-temporal similarity retrievalObtaining the similarity between the historical flood set 1 and the historical flood set 2 based on flood time sequence process similarity retrieval to obtain X2+X3The historical flood process that the field is similar to the flood is recorded as a similarity historical flood set 3;
step 4-2, recording ftargetLength of (L), sliding computation of different starting points and times (I) of a flood process in the similarity historical flood set 30To the following item I0Flood sequence f between + L-1 momentsdatabase_partAnd ftargetSum of squared deviations ofGet itMinimum corresponding item I0,bestThe + L-1 moments are used as splicing positions of the similar flood and the flood in the field; respectively determining splicing positions aiming at each flood in the similarity historical flood set 3, and after the splicing positions, adopting an equal weight method to perform weighted calculation X2+X3Average similar flood process sequence f of field similar flood processessimilarity,fsimilarityLength and X of2+X3The lengths of the shortest flood time sequences after the splicing positions in the field similar flood process are consistent and are recorded as Lsimilarity;
In the formula:representing the flow of the Kth field similar flood sequence in the similarity historical flood set 3 at the ith moment after the splicing position;
step 4-3, beyond the effective forecasting period of flood forecasting, the flood forecasting cannot provide reliable forecasting flow, and the average similar flood process fsimilarityMove up and downAnd splicing the prediction flow with the forecast flow at v moments after the confrontation moment to obtain a complete flood prediction result after the confrontation moment, namely:
6. The flood dynamic estimation method based on the rainfall flood space-time process similarity mining according to claim 1, wherein the step 5 further comprises:
step 5-1, judging flood process estimation results based on similar excavation of rainfall flood space-time processWhether flood peak information is contained or not is judged, if yes, the dynamic estimation stopping condition is not met, otherwise, if no flood peak information is contained, namely, all the flood peak information is in the process of water withdrawal, the dynamic estimation is stopped;
step 5-2, if the stopping condition is not met, moving to the next facing moment along with time, updating rainfall observation and forecast information, flood observation and forecast information in the effective forecast period, and repeating the step 2 to the step 4 to realize the flood process estimated result based on similar excavation of the rainfall flood space-time processIs dynamically updated.
7. The flood dynamic estimation method based on rainfall flood space-time process similarity excavation according to claim 1, wherein the steps 1-5 are repeated to obtain dynamic estimation results of the flood process of the hydrological station in the research area.
8. Flood dynamic estimation system, its characterized in that includes:
the system comprises a first module, a second module and a third module, wherein the first module is used for acquiring historical remote sensing inversion rainfall information, real-time remote sensing inversion rainfall information, numerical forecast rainfall information and historical site flood information of a preset number of hydrologic stations in a research area, matching the time scales of historical rainfall and flood information and constructing a hydrologic station historical rainfall flood database;
the second module is used for matching and splicing the space-time scales of the remote sensing inversion precipitation and numerical forecast precipitation information facing the earlier stage of time and observed aiming at the flood which is happening in the hydrological station, and searching historical precipitation processes with similar surface average precipitation time sequences in a historical rainfall flood database established by the first module by adopting a time sequence similarity analysis method; screening historical rainfall processes similar to the spatio-temporal process by adopting a spatio-temporal information similarity analysis method, and extracting a corresponding similarity historical flood set 1;
the third module is used for splicing flood information in an effective forecast period of constantly observed flood and flood forecast model forecast, and searching a historical similarity flood set 2 with similar time sequence process in a historical rainfall flood database by adopting a time sequence similarity analysis method;
the fourth module is used for merging the similarity historical flood set 1 and the similarity historical flood set 2 to obtain a similarity historical flood set 3, reasonably determining the splicing time point of each similar flood, calculating the average similar flood process after the splicing time point by adopting a weighted average method, and estimating the subsequent flood process through translation and splicing operation;
the fifth module judges whether the follow-up flood process estimated by the fourth module contains a flood peak or not, and stops dynamic estimation if the follow-up flood process does not contain the flood peak; otherwise, updating the rainfall flood observation and forecast information along with the time, repeatedly executing the second module to the fourth module, and dynamically estimating the development situation of the flood.
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CN114997534A (en) * | 2022-07-29 | 2022-09-02 | 长江水利委员会水文局 | Similar rainfall forecasting method and equipment based on visual features |
CN116011879A (en) * | 2023-02-01 | 2023-04-25 | 长江水利委员会长江科学院 | Ecological system stability assessment method and device, electronic equipment and storage medium |
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CN114997534A (en) * | 2022-07-29 | 2022-09-02 | 长江水利委员会水文局 | Similar rainfall forecasting method and equipment based on visual features |
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