CN104914483A - Multi-source-observation-data-based quality evaluation method of ground wire of South Pole - Google Patents

Abstract

The invention relates to a method for evaluating the quality of the Antarctic grounding wire based on multi-source observation data, comprising the following steps: 1) obtaining the relative position of the Antarctic grounding wire, qualitative and quantitative analysis evaluation indicators; 2) performing error classification according to the Antarctic grounding wire evaluation standard, The difference between the grounding lines is divided into acceptable error range, gross error and grounding line change; 3) The analysis method combined with Antarctic altimetry data, the analysis method combined with Antarctic digital elevation model, and the combination of Antarctic multi-period high The analysis method of high-resolution remote sensing images further analyzes the Antarctic grounding line data; 4) Outputs the judgment and results of the Antarctic grounding line. Compared with the prior art, the present invention determines the evaluation index of qualitative and quantitative analysis for the whole Antarctic data, classifies the errors, and combines the Antarctic altimetry point cloud data, digital elevation model and multi-period high-resolution remote sensing images for analysis, Ensure the comprehensiveness and accuracy of quality evaluation.

Description

A Quality Evaluation Method for Antarctic Grounding Wire Based on Multi-source Observational Data

technical field

The invention relates to a data quality evaluation method, in particular to a method for evaluating the quality of Antarctic grounding wires based on multi-source observation data.

Background technique

The grounding line is the boundary line between the inland ice sheet and the floating ice shelf, and is where ice flow breaks away from the ice bed. The location of the grounding line is very important for us to calculate ice sheet mass balance, simulate numerical models of ice sheet dynamics, and study the interaction between ice and ocean. In order to further understand the dynamic changes of the ground wire, we must have a precise understanding of the ground wire position. In addition, most oceanographic and glaciological applications also require knowledge of the exact location of the grounding line. The grounding wires designed by the present invention include: MOA grounding wires, which are obtained by visually interpreting the images of the Moderate Resolution Imaging Spectrometer (MODIS); ASAID grounding wires, which are obtained by visually interpreting LIMA images and using ICESat elevation point correction; InSAR grounding wires , obtained using the differential interferometric radar method; ICESat grounding line points, obtained using repeated orbital elevation anomalies. Due to the limitation of experimental conditions, the Antarctic grounding wire is seldom evaluated. The currently available field inspection methods are ground and airborne echo detection, but the coverage area is very small, and only a small-scale evaluation can be carried out.

Contents of the invention

The purpose of the present invention is to provide a method for evaluating the quality of Antarctic grounding wires based on multi-source observation data in order to overcome the above defects in the prior art, which not only fully considers the accuracy of the original remote sensing data of grounding wire products, but also takes into account the Based on the characteristics of ground wire data, the evaluation method has strong operability, and provides a new idea for solving the key problems of ground wire quality evaluation.

The purpose of the present invention can be achieved through the following technical solutions:

A method for evaluating the quality of Antarctic grounding wires based on multi-source observation data, used to process Antarctic grounding wire data, the Antarctic grounding wire data includes MOA grounding wires (from MODIS images), InSAR grounding wires (from ERS-1/2, Radarsat－1/2, ALOS PALSAR data), ICESat ground line (from ICESat laser altimetry data), ASAID ground line (from Landsat image, partially adjusted by ICESat), the method includes the following steps:

1) Obtain the relative position, qualitative and quantitative analysis and evaluation indicators of the Antarctic grounding line;

2) According to the Antarctic grounding line evaluation standard, the error classification is carried out, and the difference between the grounding lines is divided into acceptable error range, gross error and grounding line change;

3) The Antarctic grounding line data is further analyzed by combining the analysis methods of Antarctic altimetry data, the analysis method of Antarctic digital elevation model, and the analysis method of Antarctic multi-period high-resolution remote sensing images;

4) According to step 1), step 2) and step 3), output the judgment and result of the south pole grounding line.

The relative position analysis evaluation index is a penetration rate analysis index, specifically: the percentage of the MOA ground wire and the ASAID ground wire passing through the ICESat ground wire F point and I point;

The qualitative analysis evaluation index is the buffer analysis index, specifically: for the MOA grounding wire and the ASAID grounding wire, make 500 meters, 1000 meters, 2000 meters and 5000 meters buffer zone, and calculate the number and percentage of InSAR grounding wires in it ;

The quantitative analysis evaluation index is a distance analysis index, specifically: calculating the distance from each InSAR grounding line point to the MOA grounding line and the ASAID grounding line, and performing statistical analysis.

Step 2) is specifically:

201: According to the error propagation formula, the allowable error between the MOA ground wire and the InSAR ground wire data, the ASAID ground wire and the InSAR ground wire data is obtained, and the following formula is satisfied:

$\mathrm{<span\; class="notranslate">\; \&delta;</span>}<span\; class="notranslate">\; =</span>\sqrt{{{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; b</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}$

In the formula, δ is the allowable error between the two data, _{ma is the positioning error of one of the data, and m b is} the positioning error of the other data;

202: The Antarctic grounding line evaluation standard considers three times the allowable error and three times the standard deviation of the grounding line difference in each basin. If it is less than three times the allowable error, the two data are within the acceptable error range. If it is greater than three times the standard deviation, If it is greater than three times the allowable error and less than three times the standard deviation, then there is a change in the grounding line.

The analysis method combined with Antarctic altimetry data is specifically:

Using the ICESat elevation point cloud and the CryoSAT-2 elevation point cloud as the Antarctic altimetry data, they were obtained by the laser altimeter on the ice, cloud and land elevation satellites and the radar altimeter of the European Space Agency’s ice exploration satellite respectively. Where there are differences in grounding lines, use point cloud data to analyze the position of the grounding line according to the definition of the Antarctic grounding line.

The analysis method combined with the Antarctic digital elevation model is specifically:

Where there are differences in grounding lines, use the digital elevation model to obtain the elevation profile, combine the grounding line definition to analyze the grounding line position, and use the digital elevation model combined with ArcGIS to make a three-dimensional map of the area to determine the grounding line position.

The analysis method combined with multi-period high-resolution remote sensing images of Antarctica is specifically as follows:

Based on multi-stage high-resolution remote sensing images, through visual interpretation, the relative changes of ice sheets and ice shelves are analyzed, and the location of the grounding line is obtained.

The step 4) is specifically to analyze and evaluate the location of the Antarctic grounding wire according to Step 1), Step 2) and Step 3), and give suggestions for the use of the Antarctic grounding wire.

The Antarctic grounding lines are all processed in the form of points. At the same time, the whole of Antarctica will be divided into 23 watersheds according to the internationally accepted Antarctic watershed division method, and the Antarctic grounding lines in each watershed will be processed one by one.

Compared with the prior art, the present invention has the following advantages:

1) The method of the present invention overcomes the limitations of traditional methods such as ground and airborne echo detection that have a small coverage area and does not consider the change of the grounding line, determines the evaluation indicators for qualitative and quantitative analysis of the entire Antarctic data, classifies the errors, and combines the Antarctic survey High point cloud data, digital elevation models and multi-period high-resolution remote sensing images are analyzed to achieve a large-scale evaluation and ensure the comprehensiveness and accuracy of quality evaluation.

2) The method of the present invention judges the quality of the grounding wire product by adopting penetration rate, buffer zone analysis, and minimum distance calculation method according to the difference of different grounding wire expression forms. The grounding wire quality evaluated by this method not only fully considers the accuracy of the original remote sensing data of the grounding wire product, but also takes into account the characteristics of point and linear grounding wire data. The evaluation method has strong operability. Key questions provide new ideas.

Description of drawings

Fig. 1 is the flow chart of the method for evaluating the quality of Antarctic grounding wire based on multi-source observation data in the present invention;

Fig. 2 is the whole Antarctic distribution diagram of four kinds of grounding wire products involved in the present invention;

Fig. 3 is three kinds of ground wire relative positions used in the present invention, qualitative and quantitative analysis evaluation index schematic diagram;

Among them, (3a) is a schematic diagram of the relative position analysis and evaluation index of the ground wire, (3b) is a schematic diagram of the qualitative analysis evaluation index, and (3c) is a schematic diagram of the quantitative analysis evaluation index;

4 is a schematic diagram of the definition of the ground wire involved in the present invention;

Fig. 5 is the whole Antarctic distribution diagram of four kinds of grounding wire products that adopt the 9th Antarctic watershed in the present embodiment;

Fig. 6 is the data processing figure that the present invention adopts in conjunction with Antarctic altimetry data analysis method;

Among them, (6a) is a schematic diagram of the grounding line and ICESat point cloud distribution, (6b) is the profile of the ICESat elevation point cloud at positions 1 and 2, and (6c) is the ICESat elevation point cloud at positions 3, 4, 5, and 6 Profile, (6d) is the profile at positions 5 and 6 of the Antarctic ice sheet topography database BEDMAP 2;

Fig. 7 is the data processing figure that the present invention adopts in conjunction with Antarctic digital elevation model analysis method;

Among them, (7a) is a schematic cross-sectional view in the grounding line area, and (7b) is an elevation profile output by using ERS-ICESat DEM.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is carried out on the premise of the technical solution of the present invention, and detailed implementation and specific operation process are given, but the protection scope of the present invention is not limited to the following embodiments.

A quality evaluation method for Antarctic grounding lines based on multi-source observation data, which is used to process Antarctic grounding lines (grounding lines, GL) data, Antarctic grounding line data include MOA grounding lines, ASAID grounding lines, InSAR grounding lines and ICESat grounding lines, As shown in Fig. 2, the MOA ground line is obtained by visually interpreting the images of the Moderate Resolution Imaging Spectrometer (MODIS); the ASAID ground line is obtained by visually interpreting the LIMA image by using ICESat elevation point correction; the InSAR ground line is obtained by using Obtained by differential interferometric radar method; ICESat ground line points are obtained by using repeated orbital elevation anomalies. Among them, the grounding lines of MOA and ASAID are the grounding lines of the whole South Pole, and the precision is not high; the grounding lines of InSAR are point files, and the precision is high; the grounding lines of ICESat are in the form of a very small number of point pairs (points F and I), and the precision is high .

The grounding lines are all processed in the form of points. At the same time, the whole of Antarctica will be divided into 23 watersheds according to the internationally accepted Antarctic watershed division method, and the Antarctic grounding lines in each watershed will be processed one by one.

As shown in Figure 1, the method includes the following steps:

1) Obtain the relative position, qualitative and quantitative analysis and evaluation indicators of the Antarctic grounding line, as shown in Figure 3.

The relative position analysis evaluation index is the penetration rate analysis index, as shown in Figure (3a), specifically: the percentage of the MOA ground wire and the ASAID ground wire passing through the ICESat ground wire F point and I point;

Qualitative analysis evaluation index is buffer analysis index, as shown in Figure (3b), specifically: for MOA ground wire and ASAID ground wire, make 500m, 1000m, 2000m and 5000m buffer zone, and calculate InSAR ground wire in The number and percentage of them;

The quantitative analysis evaluation index is the distance analysis index, as shown in Figure (3c), specifically: calculate the distance from each InSAR ground line point to the MOA ground line and the ASAID ground line, and perform statistical analysis.

The method of the present invention considers the characteristics of grounding lines expressed in dotted and linear forms in the quality evaluation, and aims at the characteristics that the field observation data of the Antarctic grounding line is difficult to obtain, and designs indicators such as penetration rate, buffer zone analysis, and minimum distance calculation to achieve Quantitative estimation of the quality of the Antarctic grounding wire.

2) According to the Antarctic grounding line evaluation standard, the error classification is carried out, and the difference between the grounding lines is divided into acceptable error range, gross error and grounding line change. Specifically:

201: According to the error propagation formula, the allowable error between the MOA ground wire and the InSAR ground wire data, the ASAID ground wire and the InSAR ground wire data is obtained, and the following formula is satisfied:

$\mathrm{<span\; class="notranslate">\; \&delta;</span>}<span\; class="notranslate">\; =</span>\sqrt{{{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; b</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}$

In the formula, δ is the allowable error between the two data, _{ma is the positioning error of one of the data, and m b is} the positioning error of the other data.

For example, the positioning error of the MOA grounding line is 500 meters, the positioning error of the ASAID grounding line is 502 meters, the positioning error of the InSAR grounding line is 100 meters, and the positioning error of point F of the ICESat grounding line is 400 meters. The error between the two data is shown in Table 1:

Table 1 Error between the data of the two ground wires

double error double error triple error MOA&InSAR 510m 1020m 1530m ASAID&InSAR 512m 1024m 1536m

202: In order to classify the errors, the grounding line evaluation standard considers three times the allowable error and three times the standard deviation of the grounding line difference in each watershed. If it is less than three times the allowable error, the two data are within the acceptable error range. If it is greater than three If it is more than three times the allowable error and less than three times the standard deviation, it means that there is a change in the grounding line, which needs further analysis.

3) The Antarctic grounding line data is further analyzed by using the analysis method combined with Antarctic altimetry data, the analysis method combined with Antarctic digital elevation model, and the analysis method combined with Antarctic multi-period high-resolution remote sensing images.

Combining with Antarctic altimetry data analysis methods are as follows:

Using the ICESat elevation point cloud and the CryoSAT-2 elevation point cloud as the Antarctic altimetry data, the laser altimeter carried on the Ice, Cloud and Land Elevation Satellite (ICESat) and the radar altimeter of the European Space Agency's ice detection satellite were respectively used get. According to the definition of the Antarctic grounding line, as shown in Figure 4, the elevation of the ice surface tends to be consistent after crossing the grounding line and reaching the ice shelf, where, G: the position where the ice breaks away from the bedrock, that is, the position of the grounding line; F: the position affected by the tide The limit point from the affected ice area to the land; Ib: the sudden change point of the ice curve slope on the ice shelf affected by the tide; Im: the lowest point of the local topography on the ice shelf, that is, the local bottom point of the topography; H: the ice reached the approximate point for the first time The position of static balance; grounding zone: the area between the ice curve limit point and the still water point, that is, the area between F-H. Therefore, where there is a difference in the grounding line, the point cloud data is used to analyze the position of the grounding line according to the definition of the Antarctic grounding line.

Combined with the Antarctic digital elevation model, the analysis method is as follows:

Where there are differences in the grounding line, use the digital elevation model (Digital Elevation Model, DEM) to obtain the elevation profile, and combine the definition of the grounding line to analyze the position of the grounding line. Determine the location of the ground wire. The ArcGIS product line provides users with a scalable and comprehensive GIS platform.

The analysis methods combined with multi-period high-resolution remote sensing images of Antarctica are as follows:

Based on the multi-period Landsat-7 mosaic (LIMA) images, through visual interpretation, the relative changes of ice sheets and ice shelves are analyzed to obtain the location of the grounding line.

4) According to step 1), step 2) and step 3), output the judgment and results of the Antarctic grounding line, that is, analyze and evaluate the position of the Antarctic grounding line. For the data within the error range, it is recommended to use the latest data; For the part of the error, the analysis recommends a more suitable grounding wire. For each watershed in Antarctica, make a quality assessment report and provide suggestions for the use of data in each part.

Examples will be given for each step. For step 1), as shown in Figure 5, the data statistics table of the ninth watershed in Antarctica will be given. As shown in table 2:

For step 2), errors are classified according to the allowable error between the two data sets and three times the standard deviation (3*std) of the watershed in Table 2.

For step 3), it includes: as shown in Figure 6, Figure (6a) includes InSAR ground wire, MOA ground wire, ASAID ground wire and ICESat point cloud, and Figures (6b), (6c), and (6d) are ICESat elevation Point cloud profile, according to the definition of the Antarctic grounding line, the grounding line should pass through positions 2, 5, and 6.

As shown in Figure 7, Figure (7a) includes MOA grounding wire, ASAID grounding wire and InSAR grounding wire, using ERS-ICESat DEM to make elevation profile, as shown in Figure (7b), according to the definition of Antarctic grounding wire, the grounding wire should be Pass position 1.

Using multi-period LIMA images, visual interpretation will be used to detect changes in image brightness on optical images to track the boundary of the grounding ice of the ice sheet to determine the location of the grounding line.

Finally, based on the analysis of the whole Antarctica, the judgment of the quality of the grounding wire and the suggestion for the selection of the grounding wire are given. The final result shows that the present invention is applicable to the quality evaluation of Antarctic grounding wire products, and can ensure comprehensiveness and accuracy.

Claims (8)

1. A method for evaluating the quality of Antarctic grounding wires based on multi-source observation data, characterized in that it is used to process Antarctic grounding wire data, and said Antarctic grounding wire data includes MOA grounding wires, ASAID grounding wires, InSAR grounding wires and ICESat grounding wires line, the method includes the following steps: 1) Obtain the relative position, qualitative and quantitative analysis and evaluation indicators of the Antarctic grounding line; 2) According to the Antarctic grounding line evaluation standard, the error classification is carried out, and the difference between the grounding lines is divided into acceptable error range, gross error and grounding line change; 3) The Antarctic grounding line data is further analyzed by combining the analysis methods of Antarctic altimetry data, the analysis method of Antarctic digital elevation model, and the analysis method of Antarctic multi-period high-resolution remote sensing images; 4) According to step 1), step 2) and step 3), output the judgment and result of the south pole grounding line. 2. A method for evaluating the quality of Antarctic grounding wires based on multi-source observation data according to claim 1, wherein the relative position analysis evaluation index is a penetration rate analysis index, specifically: MOA grounding wire and ASAID The percentage of the ground wire passing through the ICESat ground wire F point and I point; The qualitative analysis evaluation index is the buffer analysis index, specifically: for the MOA grounding wire and the ASAID grounding wire, make 500 meters, 1000 meters, 2000 meters and 5000 meters buffer zone, and calculate the number and percentage of InSAR grounding wires in it ; The quantitative analysis evaluation index is a distance analysis index, specifically: calculating the distance from each InSAR grounding line point to the MOA grounding line and the ASAID grounding line, and performing statistical analysis. 3. a kind of Antarctic ground wire quality evaluation method based on multi-source observation data according to claim 1, is characterized in that, step 2) is specially: 201: According to the error propagation formula, the allowable error between the MOA ground wire and the InSAR ground wire data, the ASAID ground wire and the InSAR ground wire data is obtained, and the following formula is satisfied: $\mathrm{<span\; class="notranslate">\; \&delta;</span>}<span\; class="notranslate">\; =</span>\sqrt{{{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; b</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}$ In the formula, δ is the allowable error between the two data, _{ma is the positioning error of one of the data, and m b is} the positioning error of the other data; 202: The Antarctic grounding line evaluation standard considers three times the allowable error and three times the standard deviation of the grounding line difference in each basin. If it is less than three times the allowable error, the two data are within the acceptable error range. If it is greater than three times the standard deviation, If it is greater than three times the allowable error and less than three times the standard deviation, then there is a change in the grounding line. 4. A kind of Antarctic grounding line quality evaluation method based on multi-source observation data according to claim 1, is characterized in that, the analysis method of described in conjunction with Antarctic altimetry data is specifically: Using the ICESat elevation point cloud and the CryoSAT-2 elevation point cloud as the Antarctic altimetry data, they were obtained by the laser altimeter on the ice, cloud and land elevation satellites and the radar altimeter of the European Space Agency’s ice exploration satellite respectively. Where there are differences in grounding lines, use point cloud data to analyze the position of the grounding line according to the definition of the Antarctic grounding line. 5. A kind of Antarctic grounding wire quality evaluation method based on multi-source observation data according to claim 1, is characterized in that, the analysis method of described in conjunction with Antarctic digital elevation model is specifically: Where there are differences in grounding lines, use the digital elevation model to obtain the elevation profile, combine the grounding line definition to analyze the grounding line position, and use the digital elevation model combined with ArcGIS to make a three-dimensional map of the area to determine the grounding line position. 6. A method for evaluating the quality of the Antarctic grounding line based on multi-source observation data according to claim 1, wherein the analysis method combined with multi-phase high-resolution remote sensing images of the Antarctic is specifically: Based on multi-stage high-resolution remote sensing images, through visual interpretation, the relative changes of ice sheets and ice shelves are analyzed, and the location of the grounding line is obtained. 7. A method for evaluating the quality of Antarctic grounding wires based on multi-source observation data according to claim 1, wherein said step 4) is specifically grounding the Antarctic according to step 1), step 2) and step 3) The location of the Antarctic grounding line is analyzed and evaluated, and suggestions for the use of the Antarctic grounding line are given. 8. A method for evaluating the quality of Antarctic grounding lines based on multi-source observation data according to claim 1, characterized in that, said Antarctic grounding lines are all processed in the form of points, and at the same time, the Antarctic grounding line will be processed according to the internationally accepted Antarctic Basin The division method divides the whole of Antarctica into 23 watersheds, and handles the Antarctic grounding line in each watershed one by one.