CN116626782A - Double-index monitoring method for south sea summer monsoon based on wind cloud polar orbit meteorological satellite - Google Patents

Abstract

The invention discloses a dual-index monitoring method for the South China Sea summer monsoon based on Fengyun polar-orbiting meteorological satellite. The method obtains the atmospheric temperature and specific humidity of 850hPa through the polar-orbiting meteorological satellite FY-3D vertical detection instrument group VASS, and calculates the false equivalent position of 850hPa. temperature index; the ocean surface wind field data retrieved by the wind field measurement radar WindRAD of the polar-orbiting meteorological satellite FY‑3E is used to obtain the ocean surface wind speed and wind direction, and the average zonal wind index is calculated; by evaluating the FY‑3D/VASS temperature and ratio The accuracy of humidity relative to ERA5 and the accuracy evaluation index of FY‑3E/WindRAD ocean surface wind relative to MetOp‑C/ASCAT are used to verify the accuracy of monitoring the onset of the South China Sea summer monsoon with dual indicators. The present invention uses FY-3D to calculate false equivalent potential temperature and FY-3E ocean surface wind dual-indices to monitor the South China Sea summer monsoon display, and the dual-indices can well monitor the temperature and humidity field and wind field transformation during the South China Sea summer monsoon outbreak in 2022, thereby verifying the two The ability to apply satellite-like data in climate monitoring of the South China Sea summer monsoon.

Description

A dual-index monitoring method for South China Sea summer monsoon based on Fengyun polar orbiting meteorological satellite

technical field

The invention relates to the technical field of meteorological data monitoring and forecasting, in particular to a dual-index monitoring method for the South China Sea summer monsoon based on Fengyun polar-orbiting meteorological satellites.

Background technique

Asia and Australia are typical monsoon regions, forming the Asia-Australia monsoon system, and the onset of the summer monsoon indicates that the atmospheric circulation has changed from a winter type to a summer type. The Asian summer monsoon is divided into the tropical summer monsoon and the subtropical summer monsoon. The onset of the tropical summer monsoon generally goes through three stages. Generally speaking, the Asian summer monsoon is first established in the southern part of the Bay of Bengal, and then extends eastward through the Indochina Peninsula to the South China Sea in mid-May. wind area, and finally the South Asian summer monsoon breaks out. The onset of the South China Sea summer monsoon heralds the establishment of the East Asian subtropical summer monsoon and the beginning of the main rainy season. The onset of the South China Sea summer monsoon has important indications for China's climate anomalies.

At present, most of the conventional weather monitoring indicators for the South China Sea summer monsoon are defined by meteorological numerical model data, and the accuracy is affected by the performance of the model, and there will be deviations from live observations. Secondly, the satellite cloud guide wind and TBB dual indicators currently used in the business are real observations of the upper-level wind field and convective activities in the South China Sea summer monsoon region, which can well reflect the activity characteristics of the monsoon, but the cloud guide wind only provides the upper-level wind direction of the troposphere The conversion characteristics of the lower troposphere wind direction cannot be obtained, and the conversion of the lower troposphere wind field is particularly important during the onset of the South China Sea summer monsoon. There is still no good solution for monitoring the South China Sea summer monsoon with indicators in the lower troposphere.

Contents of the invention

The purpose of the present invention is to provide a dual-index monitoring method for the South China Sea summer monsoon based on Fengyun Polar Orbiting Meteorological Satellite, so as to solve the practical problems in the above-mentioned prior art.

In order to achieve the above object, the present invention provides a dual-index monitoring method for the South China Sea summer monsoon based on Fengyun Polar Orbiting Meteorological Satellite, which mainly includes the following steps:

S1, obtain the atmospheric temperature and specific humidity at 850hPa through the polar-orbiting meteorological satellite FY-3D vertical detection instrument group VASS, and process it into daily average data, and calculate the false equivalent potential temperature index at 850hPa;

S2. Obtain the ocean surface wind field data through the wind field measurement radar WindRAD of the polar-orbiting meteorological satellite FY-3E, and process it into daily average data to obtain the ocean surface wind speed and wind direction, and obtain the average zonal wind index;

S3, assessing the accuracy of FY-3D/VASS temperature and specific humidity relative to ERA5 data;

S4. Evaluate the accuracy of FY-3E/WindRAD ocean surface wind relative to Metop-C/ASCAT data;

S5, the evaluation results of S3 and S4 are used to verify the accuracy of using S1 and S2 dual indicators to monitor the onset process of the South China Sea summer monsoon.

Furthermore, the South China Sea summer monsoon area is (10°N-20°N; 110°E-120°E).

Furthermore, the daily average data needs to be matched with spatial grid points in the summer monsoon region of the South China Sea.

Further, the formula for calculating the evaluation index of accuracy described in S3 and S4 is:

Among them, Y is the tested variable, X is the test reference value variable, n is the matching sample size, The average value of the tested variable for n samples, /> Tests the reference value variable mean for n samples.

Furthermore, compared with FY-3D/VASS and ERA5 in the above-mentioned S3, the pseudo-equivalent potential temperature distribution is consistent with the seasonal advance trend, so the Fengyun polar-orbiting meteorological satellite can monitor the variation characteristics of the atmospheric temperature and humidity index during the onset of the South China Sea summer monsoon.

Furthermore, comparing FY-3E/WindRAD and Metop-C/ASCAT in the above-mentioned S4, the distribution of the ocean surface wind flow field is consistent, and the location and intensity of the high wind speed area are similar. Therefore, the Fengyun polar-orbiting meteorological satellite can monitor the wind during the South China Sea summer monsoon outbreak. Field transformation features.

Further, the accuracy of S1 and S2 dual-index monitoring of the onset process of the South China Sea summer monsoon was compared with the onset time of the South China Sea summer monsoon released by the National Climate Center.

Further, when the global coverage of the polar orbiting meteorological satellite is monitored, the average FY-3D pseudo-equivalent potential temperature and the FY-3E ocean surface wind distribution display can also be used to monitor the crossing of the South China Sea summer monsoon, which is an important indicator for the establishment of the Asian summer monsoon. Equatorial airflow, warm and humid water vapor transport, tropical depression or cyclone in the southern Indian Ocean, vortex or cyclonic storm outburst in the Bay of Bengal, and synoptic-scale systems triggering the summer monsoon onset.

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

(1) Use the temperature, humidity and ocean surface wind (low-level wind) retrieved by the FY-3 polar orbiting meteorological satellite to monitor the characteristics of the South China Sea summer monsoon activity, and realize the monitoring of different meteorological elements during the South China Sea summer monsoon activity. This invention will increase the wind field index and temperature and humidity index in the lower troposphere ocean surface on the basis of satellite remote sensing cloud guide wind and TBB dual index monitoring of summer monsoon activity in the South China Sea, so as to have a more comprehensive judgment on the intensity information of summer monsoon outbreak and activity process .

(2) For the first time, the FY-3 satellite observation data was applied to the summer monsoon monitoring, and the FY-3E ocean surface wind assessment was added, and the inversion products of similar instruments of the European Meteorological Satellite were selected as the verification source, and the daily variation of wind speed was considered The influence of characteristics on the test results.

Description of drawings

The accompanying drawings described here are used to provide a further understanding of the present invention and constitute a part of the application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations to the present invention. In the attached picture:

Fig. 1 provides a flow chart of a dual-index monitoring method for the South China Sea summer monsoon based on Fengyun Polar Orbiting Meteorological Satellite according to an embodiment of the present invention;

Figure 2 provides the density and evaluation index of FY-3D/VASS and ERA5850hPa temperature scatter points in the South China Sea summer monsoon region in April, May and June of 2022 for the embodiment of the present invention;

Fig. 3 is the scatter point density map and evaluation index of FY-3D/VASS and ERA5850hPa specific humidity in the South China Sea summer monsoon region from April to June 2022 provided by the embodiment of the present invention;

Fig. 4 is the false equivalent potential temperature of FY-3D/VASS and ERA5 850hPa from April to June 2022 provided by the embodiment of the present invention;

Fig. 5 is a scatter diagram of the ocean surface wind u of the South China Sea summer monsoon region FY-3E/WindRAD and MetOp-C/ASCAT from April to June 2022 provided by the embodiment of the present invention;

Fig. 6 is a scatter diagram of the ocean surface wind v of the South China Sea summer monsoon region FY-3E/WindRAD and MetOp-C/ASCAT from April to June 2022 provided by the embodiment of the present invention;

Fig. 7 is a scatter diagram of the ocean surface wind speed of FY-3E/WindRAD and MetOp-C/ASCAT in the South China Sea summer monsoon region from April to June 2022 provided by the embodiment of the present invention;

Fig. 8 is FY-3E/WindRAD and MetOp-C/ASCAT monthly average ocean surface wind and wind speed from April to June 2022 provided by the embodiment of the present invention;

Fig. 9 is the FY-3E/WindRAD and MetOp-C/ASCAT monthly average ocean surface wind speed deviation for April-June 2022 provided by the embodiment of the present invention;

Figure 10 is the average 850hPa FY-3D/VASS and ERA5 daily average false equivalent potential temperature (a) in the South China Sea summer monsoon region from March 1, 2022 to September 30, 2022 provided by the embodiment of the present invention, FY-3E/WindRAD, MetOp- C/ASCAT surface wind and ERA5 daily mean zonal wind (b).

The realization of the purpose of the present invention, functional characteristics and advantages will be further described in conjunction with the embodiments and with reference to the accompanying drawings.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts fall within the protection scope of the present invention.

The onset of the Asian tropical summer monsoon occurs on the ocean surface where conventional detection data are scarce. Satellites can provide real-time information on atmospheric parameters, cloud parameters, and precipitation covering the entire region for the monitoring of summer monsoon activities. In the past, the use of satellites to monitor the South China Sea summer monsoon mainly applied Carry out applied research on parameters such as brightness temperature, precipitation, and cloud guiding wind. The vertical detection instruments carried by the Fengyun Polar Orbiting Meteorological Satellite can effectively observe the three-dimensional temperature and humidity of the atmosphere under all-weather conditions, and play an important role in the monitoring of extreme weather events. The application of this observation data in the monitoring of the South China Sea summer monsoon has great potential . The wind field measurement radar carried by the FY-3E meteorological satellite launched in 2021 can observe the global ocean surface wind field. Previous data analysis shows that compared with the 850hPa wind field, changes in the ocean surface and near-surface wind can better characterize Asia. The characteristics of each monsoon system, so the embodiment of the present invention will also evaluate the application ability of the FY-3E ocean surface wind in the monitoring of the South China Sea summer monsoon. The monitoring application capability of the South China Sea summer monsoon based on the Fengyun polar orbiting meteorological satellite is verified by dual indicators. Its flowchart is shown in Figure 1.

The FY-3D meteorological satellite was launched on November 15, 2017. This paper uses the temperature and humidity data retrieved by the FY-3D/VASS instrument group[31-34 ], the vertical observation instrument group consists of three instruments, namely 4-channel microwave thermometer (MicroWave Humidity Sounder, MWHS), 5-channel microwave thermometer (MicroWave Temperature Sounder, MWTS) and 26-channel infrared spectrometer (InfraRed Atmospheric Sounder ,IRAS). The coverage of VASS temperature and humidity data is global, the spatial resolution of sub-satellite points is 15km, and there are 43 pressure layers in the vertical direction from 1013.25hPa on the ground to 0.1hPa in the sky. The embodiment of the present invention uses a pressure layer of 839.95hPa. The stable and reliable FY-3D/VASS temperature and humidity retrieval data time starts from April 2019.

The FY-3E meteorological satellite was successfully launched in July 2021, and it is also the world's first civil morning and evening orbit meteorological satellite. The satellite is loaded with 11 sets of remote sensing instruments, of which 3 are newly developed, 7 are upgraded, and 1 is business inherited [35,37]. The FY-3E meteorological satellite has realized the combination of active and passive ocean surface wind field detection capabilities, and added a dual-frequency wind field measurement radar. High-precision measurement information of global ocean surface wind fields. Wind field measurement radar obtains wind field information including wind speed and wind direction on the global ocean surface through backscatter measurements of the earth system. The wind field measurement radar is a dual-frequency, dual-polarization cone-scanning radar. It achieves high-precision wind field measurement through on-board internal calibration and on-orbit active external calibration. It has two frequencies, C-band (5.3GHz) and Ku-band (13.265GHz) ), four antennas with HH and VV on both frequencies. Each pixel emits light at multiple viewing angles. The minimum detectable wind speed is 3m/s. The embodiment of the present invention selects the wind field measurement radar ocean surface wind product, which is daily data, divided into ascending orbit (evening) and descending orbit (early morning) every day, and the data is equilongitude and latitude grid point data (0.25°×0.25°) , covering the global ocean surface, this paper processes the daily ascending and descending orbit data into daily average data. The time to observe the South China Sea summer monsoon area is around 10:00 in the evening (UTC) and around 22:00 in the morning.

The onset of the South China Sea summer monsoon should meet the following three conditions:

1) Time occurs at pentad 25 and later;

2) The average ocean surface wind zonal wind in the South China Sea summer monsoon monitoring area is greater than zero and lasts for at least 2 pentads (including 2 pentads)

3) The pentad average 850hPa pseudo-equivalent potential temperature in the South China Sea summer monsoon monitoring area is greater than or equal to 340K and lasts for at least two pentads (including two pentads). At this time, most of the atmosphere in the South China Sea summer monsoon monitoring area is stable and presents high temperature and high humidity characteristics.

Description of two data sources for comparative analysis in the embodiment:

The temperature, humidity, wind field data that ERA5 reanalysis data adopts in the embodiment of the present invention are all European Center for Medium-Range Weather Forecasts (European Center for Medium-Range Weather Forecasts, ECWMF) reanalysis data set (ERA5), and this data set merges Model and global observation data, the horizontal spatial resolution is 0.25° (longitude) × 0.25° (latitude), and the time resolution is 1h. In the embodiment of the present invention, it is processed into daily average data, and the pressure layer used is 850hPa.

The ASCAT scatterometer used in the embodiments of the present invention is one of the instruments carried by the Meteorological Service (Metop) polar satellite launched by the European Space Agency (ESA) and operated by the European Union Meteorological Satellite Organization (EUMETSAT). Metop-C launched on November 7, 2018, the horizontal stress equivalent wind vector at a height of 10m, including wind speed and wind direction. Wind speed is measured in meters per second. Wind speeds range from 0-50 m/s, but wind speeds over 25 m/s are generally less reliable. The standard deviation accuracy of the wind component should be better than 2m/s, and the wind speed deviation should be less than 0.5m/s. The spatial resolution is about 12.5km, covering twice a day. In the embodiment of the present invention, the data is processed to a daily average resolution of 0.25°×0.25°. The time to observe the South China Sea summer monsoon area is around 02:00 in the morning (UTC) and around 14:00 in the night.

In the embodiment of the present invention, the application evaluation is carried out by using the South China Sea summer monsoon monitoring index operated by the National Climate Center, including the 850hPa pseudo-equivalent potential temperature index and the ocean surface zonal wind index. The pseudo-equivalent potential temperature is calculated as:

e=prs×q/(0.62197+q)

tlcl=55.0+2840.0/(3.5×logT-loge-4.805)

θ＝T×(1000/prs) ^{0.2854×(1.0-0.28×q)}

Among them, θ _se is the pseudo-equivalent potential temperature, θ is the potential temperature, prs=850hPa, T is the temperature (unit: K), and q is the specific humidity (unit: kg/kg). The area of the South China Sea summer monsoon is (10°N-20°N; 110°E-120°E). Average zonal winds.

The following evaluation index calculation formulas are used for mean deviation (MB), mean absolute error (MAE), root mean square error (RMSE) and correlation coefficient (CC):

Among them, Y is the tested variable, X is the test reference value variable, n is the matching sample size, The average value of the tested variable for n samples, /> Tests the reference value variable mean for n samples.

Firstly, the embodiment carries out the FY-3D/VASS temperature and humidity assessment of the South China Sea summer monsoon monitoring. In this embodiment, the time period is selected from April 1 to June 30, 2022, covering the entire process of the South China Sea summer monsoon outbreak in 2022. Atmospheric temperature and specific humidity at 850hPa are obtained through the polar-orbiting meteorological satellite FY-3D vertical detection instrument group VASS, and processed into daily average data to calculate the false equivalent potential temperature index of 850hPa.

Then, according to the above evaluation index calculation formula, the 850hPa FY-3D/VASS temperature and ERA5 temperature scatter density map and evaluation index display in April, May and June 2022 are obtained (Figure 2), and the matching sample size in April, May and June It was about 80,000, and the maximum matching sample size in May was 86,000. The average deviation and average absolute error in April were the smallest, respectively -0.39 and 1.02°C, and the correlation coefficient was the largest at 0.46. The average deviation in May was -0.73, the absolute average deviation was 1.11°C, and the root mean square error was the smallest at 1.55°C. The minimum correlation coefficient in June is 0.27. Overall, the average distribution from April to June shows that the temperature of FY-3D/VASS 850hPa is abnormally high or low, with an average low temperature of 0.6°C, an average absolute deviation of 1.1°C, and a root mean square error of 1.6°C.

The 850hPa FY-3D/VASS specific humidity and ERA5 specific humidity scatter point density map and evaluation indicators in April, May and June 2022 (Figure 3), the specific humidity correlation coefficient and scatter point distribution deviate from the temperature, April-June There were samples with abnormally large and small specific humidity, and the specific humidity was generally low. In May and June, the correlation coefficients are both small, and the high scatter density is distributed below the trend line, and the average deviation in June is relatively small at -0.15g/kg. The average from April to June shows that the average deviation is -0.53g/kg, the average absolute error is 2.25g/kg, and the root mean square error is 2.97g/kg.

FY-3D/VASS 850hPa temperature and specific humidity in the South China Sea summer monsoon region are lower than ERA5 as a whole on average from April to June. Using the FY-3D/VASS temperature and humidity to calculate the 850hPa pseudo-equivalent potential temperature distribution through the above formula, the research shows that the 850hPa region The average pseudo-equivalent potential temperature of 340K can be used as an indicator of the onset of the South China Sea summer monsoon. Therefore, comparative analysis of FY-3D/VASS and ERA5850hPa pseudo-equivalent potential temperature distribution (Figure 4). It can be seen that during April-June during the onset of the South China Sea summer monsoon in 2022, the false equivalent potential temperature retrieved by the satellite is slightly lower by 1-2K. Before the onset of the South China Sea summer monsoon in April, the false equivalent potential temperature in the lower monsoon area of the South China Sea was lower than 340K, and the false equivalent potential temperature was greater than 340K in May to control the South China Sea summer monsoon area and the Bay of Bengal, and it was further pushed northward to Jiangnan and South China in June. The FY-3D/VASS and ERA5 pseudo-equivalent potential temperature distributions are consistent with the seasonal advancement trends, and to a certain extent, they can monitor the characteristics of the atmospheric temperature and humidity index changes during the onset of the South China Sea summer monsoon.

The steps for FY-3E ocean surface wind assessment in the South China Sea summer monsoon monitoring are as follows:

The FY-3E wind field measurement radar is the first active remote sensing instrument mounted on the Fengyun series of meteorological satellites. The ocean surface wind field retrieved by it has been a stable operational product since March 1, 2022. In order to analyze its summer monsoon in the South China Sea In terms of applicability in monitoring, a comparative analysis was made between the data and the ocean surface wind field retrieved by EUMETSAT's ASCAT carried on the Metop-C satellite. The time period is selected from April 1 to June 30, 2022, covering the entire process of the onset of the South China Sea summer monsoon in 2022. Due to the different transit times of the two satellites, the time of sweeping the summer monsoon area in the South China Sea is early morning/evening (FY-3E, around 22:00 and 10:00) and morning/night (Metop-C, around 02:00 and 14:00 00 or so), so they are all processed into daily average data for evaluation, and the same daily average data are used for spatial grid matching in the South China Sea summer monsoon region.

In the monitoring of the summer monsoon in the South China Sea, not only the wind speed, but also the meridional wind v and the zonal wind u components are paid attention to, because these three quantities are tested and evaluated separately, and the matching samples per month from April to June 2022 are about 20,000 . The evaluation of the zonal wind u shows (Figure 5), according to the above evaluation calculation formula, the correlation coefficients in April and May are 0.66 and 0.62, respectively, and the correlation coefficient in June is relatively low at 0.52, and the scattered high-density areas in April are distributed between 0- 5m/s, indicating that the summer monsoon area in the South China Sea is dominated by easterly winds. In May, the scattered high-density areas are distributed between -5 and 5m/s, and in June, they are between -5 and 0m/s. The transformation of the zonal wind before and after the onset of the South China Sea summer monsoon. The average deviation of the zonal wind from April to June 2022 is about -0.58m/s, the average absolute error is about 2.29m/s, the root mean square error is about 3.01m/s, and the average correlation coefficient is 0.70. According to the evaluation of direction wind v (Figure 6), the correlation coefficients from April to June are all above 0.75, the average correlation coefficient is 0.85, and the average deviations are all positive, indicating that compared with MetOp-C/ASCAT, the south wind component is slightly stronger , and the average deviation in June is the largest. The absolute average deviation and root mean square error of the meridional wind v are smaller than the zonal wind u, and the difference before and after the onset of the summer monsoon is small. The average deviation from April to June is 0.52m/s, and the average absolute error is 2.01m/s , the average root mean square error is 2.70m/s. The wind speed assessment shows (Figure 7), the correlation coefficient in April is 0.87 at the maximum, the average correlation coefficient in April-June is 0.79, the average deviation is about -0.46m/s, the absolute deviation is 1.56m/s, and the root mean square error is 2.00 m/s or so.

Judging from the average distribution from April to June in 2022 (Figure 8), the distribution of FY-3E/WindRAD and MetOp-C/ASCAT ocean surface wind flow fields is consistent, and the location and intensity of the high wind speed area are similar. In April, before the onset of the Asian summer monsoon, the summer monsoon area in the South China Sea was northeasterly. The wind speed in the northeastern part of the South China Sea and east of the Philippines was relatively high, and the wind speed of FY-3E was slightly weaker by about 1m/s. At this time, the cross-equatorial airflow along the east coast of Africa has not yet been established, the Arabian Sea is controlled by an anticyclone, and a southwesterly wind begins to appear in the ocean south of India, extending to the southwest of the Bay of Bengal. In May, during the successive onset of the Asian summer monsoon, the cross-equatorial airflow over the eastern African ocean was strong and turned into a westerly or southwesterly wind within the 0-10N latitude band and extended to the Indo-China Peninsula and the northern part of the South China Sea. The summer monsoon broke out in the Bay of Bengal and the South China Sea. , it can be seen from the distribution of large wind speed areas that the wind speed of FY-3E is slightly smaller by about 1m/s. In June, the cross-equatorial airflow was further strengthened, and the maximum wind speed in the concerned area appeared in the southwest of the Arabian Sea, which was above 11m/s. The Asian tropical summer monsoon region was controlled by westerly and southwesterly winds.

The daily average false equivalent potential temperature of the South China Sea summer monsoon region calculated using FY-3D and ERA5 data shows (Figure 10a): the average false equivalent potential temperature of the ERA5 region is slightly higher than that of FY-3D as a whole, and from mid-March to mid-April Significantly larger, the average pseudo-equivalent potential temperature of the ERA5 region exceeded 340K in the middle and late March. Starting from April 28, except for May 11 and 12, the ERA5 false equivalent potential temperature is greater than 340K, which meets one of the indicators for the onset of the South China Sea summer monsoon. The average false equivalent potential temperature in the FY-3D region also began to appear greater than 340K on April 28, but fell back below 340K after May 1, fluctuated on May 8-9, and began to remain relatively stable above 340K around the 17th or nearby.

The South China Sea summer monsoon monitoring index of the National Climate Center is (10-20N; 110-120E) regional average zonal wind u of 850hPa. Figure 10b is the time series of regional average zonal wind from March 1st to September 30th, 2022 (10-20N; 110-120E). It can be seen that FY-3E/WindRAD and MetOp-C/ASCAT ocean surface wind extraction indicators The change trend is basically the same, and the onset time of the South China Sea summer monsoon is one day later than ERA5 (May 10). The change of the zonal wind direction during the onset of the South China Sea summer monsoon in 2022 has been well monitored.

An embodiment also verifies the ability of the FY-3 meteorological satellite to evolve atmospheric parameters before and after the 2022 South China Sea summer outburst.

The monitoring of the East Asian summer monsoon circulation by the National Climate Center shows that the South China Sea summer monsoon will break out in the 3rd pentad in May, which is slightly earlier than normal (the 4th pentad in May), and its intensity is close to normal to weak (note: climatologically, 5 For example, the third season of May is May 11-15 (http://cmdp.ncc-cma.net/climate/monsoon.php). The monitoring of the South China Sea summer monsoon temperature and humidity indicators and wind field indicators by the FY-3 meteorological satellite also showed that the South China Sea summer monsoon broke out on the third day of May 2022. FY-3 was used to analyze the characteristics of the atmospheric parameters and the outbreak process of the South China Sea summer monsoon before and after the onset.

Studies have shown that the explosive vortex or cyclonic storm in the Bay of Bengal will trigger the onset of the South China Sea summer monsoon. Before the onset of the South China Sea summer monsoon in 2022, the Bay of Bengal will be affected by the cyclone "Asani" in the North Indian Ocean (English: Severe CyclonicStorm Asani, Indian Meteorological Service: BOB 03, Joint Typhoon Warning Center: 02B, standard translation of China National Meteorological Center: Asani), a tropical disturbance in the Bay of Bengal was generated on May 5, the cyclone was numbered on May 8, and then gradually moved to the northwest, on May 11 It landed on the coast of Andhra Pradesh, India, and then gradually weakened and dissipated. The maximum intensity reached the intensity of a tropical cyclone identified by the Joint Typhoon Warning Center and the intensity of a severe cyclone identified by the Indian Meteorological Department and the Central Meteorological Observatory. "Assani" brought strong wind and rain to India and Bangladesh, killing at least three people, but failed to significantly ease the extreme heat in South Asia.

Before the outbreak of the South China Sea summer monsoon, tropical cyclone activities also appeared in the southern Indian Ocean. On May 5, a low pressure formed in the central part of the Indian Ocean. The system gradually developed and was named Karim by the Regional Specialized Meteorological Center (RSMC) Reunion Island on Saturday, May 7. Karim moved southeastward and moved into the Australian area on Sunday, May 8, and further intensified at 0600 (UTC) on May 8, reaching Category 2 at 95 kilometers per hour (km/h). Karim maintained a Category 2 intensity on May 9 as the system moved steadily southward. On May 10, Karim reached a peak intensity of 60 knots (110 km/h), just below Category 3 intensity. At night, as circumstances turned unfavorable, Karim began to weaken. Karim transitioned to a subtropical system early on May 11, but continued to produce storm winds and high winds, aided by a strong pressure gradient between the system and a ridge of high pressure to the south.

The joint influence of tropical cyclone Karim in the southern Indian Ocean and cyclone Asani in the northern Indian Ocean has increased the intensity of the westerly wind in the Indian Ocean between the two cyclones. The surface wind speed in the south of the Bay of Bengal exceeds 10 m/s in some areas, which is conducive to the advancement of the summer monsoon to the South China Sea in the later period. Before and after the onset of the South China Sea summer monsoon, the pentad average FY-3D pseudo-equivalent potential temperature and FY-3E ocean surface wind distribution show that: in the first pentad of May, the cross-equatorial airflow over the eastern African ocean was established, and the Indian Ocean was westerly in the range of 0-5N. There is a southerly wind in the west of the Bay of Bengal. At this time, the South China Sea is controlled by northeasterly or easterly winds. The northern part of the South China Sea is relatively strong. There is a low-pressure circulation in the tropical area near 90-100E south of the equator. This low-pressure circulation is conducive to the strengthening of the westerly wind on the north side. ; On the second day of May, the most typical feature is that two low-pressure systems formed in the Bay of Bengal and the southern hemisphere ocean surface respectively, and the cyclone "Assani" affected the Bay of Bengal. Affected by "Assani", the South China Sea and Indochina Peninsula The easterly wind from the south ocean turned to the southeast and merged into the cyclonic storm; the cyclone storm landed and died in the Bay of Bengal on the 3rd of May, the most obvious feature was the increase in the pseudo-potential temperature of the Indian Peninsula, the Bay of Bengal, and the Indochina Peninsula, and at the same time, the cross-equatorial airflow was affected. The suction effect of "Assani" is stronger than that in the second month of May, and the southwest wind controls the Bay of Bengal and extends eastward to the summer monsoon area of the South China Sea; in the fourth month of May, the south of the summer area of the South China Sea continues to be controlled by the southwest wind, and the north is cold Influenced by the air, there is a northeasterly wind, and the false equivalent potential temperature in most areas is higher than 340K.

The storm in the Bay of Bengal has a suction effect on the cross-equatorial airflow, which strengthens the westerly wind on the tropical ocean north of the equator. After the cyclonic storm weakens and dies, the strong southwest monsoon crosses the Indochina Peninsula and reaches the South China Sea, triggering the onset of the South China Sea summer monsoon. Although affected by the cold air, there was a northeasterly wind in the northern part of the South China Sea on the fourth day of May, but the strong southwesterly wind over the northern Indian Ocean made the entire South China Sea summer monsoon area controlled by a stable southwesterly wind after the cold air passed. On the 5th day of May, the false equivalent potential temperature above 340K, which represents the warm and humid air mass, advances to South China and the Jiangnan region. The entire South China Sea area is affected by the southwest summer monsoon. On the sixth day of the month, the South China Sea continues to be controlled by the southwest summer monsoon, and the warm and humid air mass is further pushed northward to the Yangtze River Basin.

The embodiment of the present invention carries out FY-3D/VASS temperature and humidity, FY-3E/WindRad ocean surface wind data application evaluation for specific areas and specific times, analyzes the differences between Fengyun satellite inversion atmospheric parameters and other data, and monitors the business The temperature and humidity indicators and wind field indicators of the South China Sea summer monsoon were evaluated, and the onset process of the South China Sea summer monsoon in 2022 was analyzed.

In the embodiment, FY-3D/VASS 850hPa temperature and specific humidity and ERA5 are compared with the South China Sea summer monsoon region in April-June. The average evaluation shows that the average temperature deviation is -0.6°C, the average absolute deviation is 1.1°C, and the root mean square error is 1.6°C; the average deviation of specific humidity is -0.53g/kg, the average absolute error is 2.25g/kg, and the root mean square error is 2.97g/kg. The pseudo-equivalent potential temperature calculated using the FY-3D/VASS temperature and specific humidity is slightly lower by 1-2K in April-June during the onset of the South China Sea summer monsoon in 2022. The distribution trend is consistent with the seasonal advancement trend, which can monitor the variation characteristics of the atmospheric temperature and humidity index during the onset of the South China Sea summer monsoon.

In the example, the FY-3E/WindRAD ocean surface wind and the Metop-C/ASCAT ocean surface field compared with the April-June average assessment of the South China Sea summer monsoon region show that the average deviation of the zonal wind in April-June 2022 is about negative. The average wind direction deviation is positive, and the wind speed assessment shows that the average correlation coefficient from April to June is 0.79, the average deviation is about -0.46m/s, the absolute deviation is 1.56m/s, and the root mean square error is about 2.00m/s. FY-3E/WindRAD and MetOp-C/ASCAT have the same distribution of ocean surface wind flow field, and the location and intensity of the high wind speed area are close. From the distribution of average deviation levels from April to June, it can be seen that the average deviation in the Asian summer monsoon region, including the tropical Indian Ocean south of the equator, and the western Northwest Pacific Ocean, is generally negative. This is partly due to the difference in the transit time of the two satellites and the daily variation of the average wind speed. related.

Example Using FY-3D to calculate pseudo-equivalent potential temperature and FY-3E ocean surface wind dual indicators to monitor the South China Sea summer monsoon shows that the dual indicators are very good for monitoring the temperature and humidity field and wind field transformation during the outbreak of the South China Sea summer monsoon in 2022, the accuracy and the National Climate Center The onset time of the South China Sea summer monsoon released by the business is basically the same, both in the third month of May. In the early stage of the onset of the South China Sea summer monsoon, in early May, the tropical cyclone “Karim” in the southern Indian Ocean and the storm “Assani” in the Bay of Bengal in the northern Indian Ocean sucked the westerly wind near the equator, which strengthened the westerly wind on the tropical ocean north of the equator, and the cyclonic storm After weakening and dying out, the strong southwest monsoon crossed the Indochina Peninsula and reached the South China Sea, causing the onset of the South China Sea summer monsoon.

The embodiment of the present invention is based on the multi-instrument vertical detection capability of the Fengyun polar-orbiting meteorological satellite, to carry out the monitoring of the atmospheric temperature and humidity conversion characteristics before and after the South China Sea summer monsoon outbreak, and to carry out the ocean surface wind retrieval based on the new instrument wind field measurement radar carried by the FY-3E meteorological satellite. The wind field changes before and after the onset of the South China Sea summer monsoon. Through different data verification, it shows the application ability of the two types of satellite data in the South China Sea summer monsoon climate monitoring. In addition to real-time monitoring of the transformation of atmospheric parameters in the South China Sea summer monsoon region, the global polar-orbiting meteorological satellites can also monitor the cross-equatorial airflow, warm and humid water vapor transport, tropical depression in the southern Indian Ocean or Cyclones, Bay of Bengal outburst vortices or cyclonic storms, etc., and synoptic-scale systems triggering summer monsoon onset. In turn, the monitoring and forecasting of the South China Sea summer monsoon based on the Fengyun Meteorological Satellite can be carried out, which can be mutually corroborated with the meteorological numerical model or reanalysis data.

The present application is described with reference to flowcharts and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present application. It should be understood that each procedure and/or block in the flowchart and/or block diagram, and a combination of procedures and/or blocks in the flowchart and/or block diagram can be realized by computer program instructions. These computer program instructions may be provided to a general purpose computer, special purpose computer, embedded processor, or processor of other programmable data processing equipment to produce a machine such that the instructions executed by the processor of the computer or other programmable data processing equipment produce a An apparatus for realizing the functions specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing apparatus to operate in a specific manner, such that the instructions stored in the computer-readable memory produce an article of manufacture comprising instruction means, the instructions The device realizes the function specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions can also be loaded onto a computer or other programmable data processing device, causing a series of operational steps to be performed on the computer or other programmable device to produce a computer-implemented process, thereby The instructions provide steps for implementing the functions specified in the flow chart or blocks of the flowchart and/or the block or blocks of the block diagrams.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the technical principle of the present invention, some improvements and modifications can also be made. It should also be regarded as the protection scope of the present invention.

Claims (8)

1. A dual index monitoring method for the South China Sea summer monsoon based on Fengyun Polar Orbiting Meteorological Satellite, is characterized in that the method comprises the following steps: S1, obtain the atmospheric temperature and specific humidity at 850hPa through the polar-orbiting meteorological satellite FY-3D vertical detection instrument group VASS, and process it into daily average data, and calculate the false equivalent potential temperature index at 850hPa; S2. Obtain the ocean surface wind field data through the wind field measurement radar WindRAD of the polar-orbiting meteorological satellite FY-3E, and process it into daily average data to obtain the ocean surface wind speed and wind direction, and obtain the average zonal wind index; S3, assessing the accuracy of FY-3D/VASS temperature and specific humidity relative to ERA5 data; S4. Evaluate the accuracy of FY-3E/WindRAD ocean surface wind relative to Metop-C/ASCAT data; S5, the evaluation results of S3 and S4 are used to verify the accuracy of using S1 and S2 dual indicators to monitor the onset process of the South China Sea summer monsoon. 2. a kind of South China Sea summer monsoon dual index monitoring method based on Fengyun polar orbiting meteorological satellite according to claim 1 is characterized in that, the South China Sea summer monsoon area is (10 ° N-20 ° N; 110 ° E-120 ° E ). 3. A dual-index monitoring method for the South China Sea summer monsoon based on Fengyun polar-orbiting meteorological satellites according to claim 1, wherein the daily average data needs to be matched with spatial grid points in the South China Sea summer monsoon region. 4. A kind of double index monitoring method based on Fengyun polar-orbiting meteorological satellite South China Sea summer monsoon according to claim 1, it is characterized in that, the evaluation index calculation formula of the accuracy described in S3 and S4 is: Among them, Y is the tested variable, X is the test reference value variable, n is the matching sample size, The average value of the tested variable for n samples, /> Tests the reference value variable mean for n samples. 5. A kind of double index monitoring method based on Fengyun polar-orbiting meteorological satellite South China Sea summer monsoon according to claim 1, it is characterized in that, compare FY-3D/VASS and ERA5 in the described S3, pseudo-equivalent potential temperature distribution and seasonal advancement The trend is consistent, so the Fengyun polar-orbiting meteorological satellite can monitor the variation characteristics of the atmospheric temperature and humidity index during the onset of the South China Sea summer monsoon. 6. A kind of double index monitoring method based on Fengyun polar orbiting meteorological satellite South China Sea summer monsoon according to claim 1, it is characterized in that, compare FY-3E/WindRAD and Metop-C/ASCAT in the described S4, ocean surface wind flow field The distribution is consistent, and the location and intensity of the high wind speed area are close. Therefore, the Fengyun polar orbiting meteorological satellite can monitor the characteristics of the wind field transformation during the onset of the South China Sea summer monsoon. 7. A method for monitoring the South China Sea summer monsoon dual index based on Fengyun Polar Orbiting Meteorological Satellite according to claim 1, characterized in that the S1 and S2 dual index monitor the accuracy of the South China Sea summer monsoon outbreak process and the South China Sea summer monsoon issued by the National Climate Center. The onset time of the summer monsoon was compared and verified. 8. The South China Sea summer monsoon dual-index monitoring method based on Fengyun polar orbiting meteorological satellite according to claim 1, is characterized in that, when the global coverage monitoring of said polar orbiting meteorological satellite is average FY-3D false equivalent potential temperature and FY-3E ocean The surface wind distribution display can also be used to monitor the cross-equatorial airflow, warm and humid water vapor transport, tropical depression or cyclone in the southern Indian Ocean, vortex or cyclonic storm outbreak in the Bay of Bengal, and synoptic scale The triggering effect of the system on the summer monsoon onset.