Volume 47,Issue 4,2019 Table of Contents
2019, 47(4):539-545.
Abstract:
The FY3D polar orbiting meteorological satellite is the latest generation of polar orbiting meteorological satellites. Its image data contain abundant surface information such as vegetation, rivers, mountains and so on. It plays an important role in the monitoring of land resource survey and land surface type change. However, nearly twothirds of each remote sensing image is covered by clouds and fogs, so it is impossible to obtain directly surface information under the clouds for product application. The technology of data synthesis in clear sky is very important.The technology of combining three standards, i.e., minimum reflectance synthesis, maximum vegetation index synthesis and sigma synthesis, is proposed innovatively, by using the advanced synthesis technology of multitime meteorological satellite remote sensing data, the 250m resolution remote sensing data of the FY3D mediumresolution spectral imager (MERSIII) can be automatically generated, which can remove the clouds and cloud shadows.
The FY3D polar orbiting meteorological satellite is the latest generation of polar orbiting meteorological satellites. Its image data contain abundant surface information such as vegetation, rivers, mountains and so on. It plays an important role in the monitoring of land resource survey and land surface type change. However, nearly twothirds of each remote sensing image is covered by clouds and fogs, so it is impossible to obtain directly surface information under the clouds for product application. The technology of data synthesis in clear sky is very important.The technology of combining three standards, i.e., minimum reflectance synthesis, maximum vegetation index synthesis and sigma synthesis, is proposed innovatively, by using the advanced synthesis technology of multitime meteorological satellite remote sensing data, the 250m resolution remote sensing data of the FY3D mediumresolution spectral imager (MERSIII) can be automatically generated, which can remove the clouds and cloud shadows.
2019, 47(4):546-551.
Abstract:
There are a variety of humidity measurement techniques, and the dewpoint humidity measurement technology has great advantages The instrument designed based on dewpoint humidity measurement technology can achieve higher accuracy in the whole range In this paper, based on the calculation formula of saturated vapor pressure from 〖WTBX〗Guide to Meteorological Instrument Observation Methods〖WTBZ〗, the standard uncertainty of relative humidity under different degrees of standard uncertainty of dew point (frost point) temperature is calculated, combined with the theory of error transfer of uncertainty, to explore the advantages of dewpoint humidity measurement technology in accuracy The results show that the standard uncertainty of relative humidity is larger under low temperature and high humidity in the temperature range of -60 to 60 ℃; when the environment temperature and dew point (frost point) measurement standard uncertainty are 01 ℃, the relative humidity measurement standard uncertainty is less than 20%, which meets the minimum requirements of standard uncertainty of humidity standard in the 〖WTBX〗Guide〖WTBZ〗 〖WTBX〗to Meteorological Observation Methods〖WTBZ〗; when the environment temperature and dew point (frost point) measurement standard uncertainty are 03 ℃ (or 05 ℃) and 01 ℃, relative humidity measurement standard uncertainty is less than 43% (or 70%) It can be seen that in the case of low temperature, the relative humidity measurement standard uncertainty of the dew point instrument has obvious advantages
There are a variety of humidity measurement techniques, and the dewpoint humidity measurement technology has great advantages The instrument designed based on dewpoint humidity measurement technology can achieve higher accuracy in the whole range In this paper, based on the calculation formula of saturated vapor pressure from 〖WTBX〗Guide to Meteorological Instrument Observation Methods〖WTBZ〗, the standard uncertainty of relative humidity under different degrees of standard uncertainty of dew point (frost point) temperature is calculated, combined with the theory of error transfer of uncertainty, to explore the advantages of dewpoint humidity measurement technology in accuracy The results show that the standard uncertainty of relative humidity is larger under low temperature and high humidity in the temperature range of -60 to 60 ℃; when the environment temperature and dew point (frost point) measurement standard uncertainty are 01 ℃, the relative humidity measurement standard uncertainty is less than 20%, which meets the minimum requirements of standard uncertainty of humidity standard in the 〖WTBX〗Guide〖WTBZ〗 〖WTBX〗to Meteorological Observation Methods〖WTBZ〗; when the environment temperature and dew point (frost point) measurement standard uncertainty are 03 ℃ (or 05 ℃) and 01 ℃, relative humidity measurement standard uncertainty is less than 43% (or 70%) It can be seen that in the case of low temperature, the relative humidity measurement standard uncertainty of the dew point instrument has obvious advantages
2019, 47(4):552-562.
Abstract:
Using the Pearson correlation coefficient, absolute and relative error, and scattered point diagram methods, the quality of the combined weather radar wind field (WID v1.0) display products are evaluated. The results show: (1) The product has higher correlation with radiosonde data; there is no systematic difference between the two data sets; and the wind direction correlation is better than the wind speed correlation. (2) As the height rises, the correlation coefficient between the two data sets decreases, and the wind field data availability is higher at altitudes below 500 hPa. (3) The quality of WID v1.0 products has closely relationship with precipitation types, and largescale precipitation is conducive to improve the quality of wind field inversion. The product quality decreases in the situation of nonmeteorological echoes and strong convective weather. (4) The product quality has certain relationship with the complexity of terrain.
Using the Pearson correlation coefficient, absolute and relative error, and scattered point diagram methods, the quality of the combined weather radar wind field (WID v1.0) display products are evaluated. The results show: (1) The product has higher correlation with radiosonde data; there is no systematic difference between the two data sets; and the wind direction correlation is better than the wind speed correlation. (2) As the height rises, the correlation coefficient between the two data sets decreases, and the wind field data availability is higher at altitudes below 500 hPa. (3) The quality of WID v1.0 products has closely relationship with precipitation types, and largescale precipitation is conducive to improve the quality of wind field inversion. The product quality decreases in the situation of nonmeteorological echoes and strong convective weather. (4) The product quality has certain relationship with the complexity of terrain.
4 Research and Implementation of 3D Visualization of Wind Profiler Radar Wind Fields Based on WebGL
2019, 47(4):563-570.
Abstract:
Aiming at this problem that the 2D display systems of wind profiler radar cannot display 3D wind fields, the 3D visualization method of of wind fields from the wind profiler radar based on WebGL is studied in this paper. The principles and advantages of 3D graphics rendering based on WebGL are introduced, and the 3D modeling and rendering method of wind fields from wind profiler radar are described in detail. On the basis of this method, a 3D visualization system for the wind fields from wind profiler radar based on the B/S mode is developed, and the functional characteristics and advantages of the system are introduced. Compared with the 2D display system, the 3D visualization system presents the spatial distribution of the wind fields in a more intuitive and realistic form, and users can observe the 3D wind fields from any angle of view, which is convenient for meteorologists to analyze wind convergence (divergence) and boundary layer convergence lines, and provides an effective technical means for monitoring and forecasting severe convective weather.
Aiming at this problem that the 2D display systems of wind profiler radar cannot display 3D wind fields, the 3D visualization method of of wind fields from the wind profiler radar based on WebGL is studied in this paper. The principles and advantages of 3D graphics rendering based on WebGL are introduced, and the 3D modeling and rendering method of wind fields from wind profiler radar are described in detail. On the basis of this method, a 3D visualization system for the wind fields from wind profiler radar based on the B/S mode is developed, and the functional characteristics and advantages of the system are introduced. Compared with the 2D display system, the 3D visualization system presents the spatial distribution of the wind fields in a more intuitive and realistic form, and users can observe the 3D wind fields from any angle of view, which is convenient for meteorologists to analyze wind convergence (divergence) and boundary layer convergence lines, and provides an effective technical means for monitoring and forecasting severe convective weather.
2019, 47(4):571-580.
Abstract:
In order to accurately determine the growth stage of corn, remotely monitor the growth of corn and analyze the relationship between growth stage and field environment elements, this paper proposes a deep local correlation neural network to overcome the multimodal and fuzzy problems in the identification of corn growth stages. In the Oxford VGGNet (Visual Geometry Group Net) model, a new supervised layer, namely the local correlation loss layer, is added to improve the discriminating capability of deep features. Based on the proposed new image recognition algorithm for corn growth stages, the environmental element monitoring function is expanded, and a corn farmland monitoring system based on deep learning is designed. The system consists of a corn farmland monitoring device and a cloud server. The monitoring device collects corn images, meteorological elements and field location data, and sends them to the cloud server through a 4G wireless internet. The cloud server uses the deep local correlation neural network to identify the growth stages, and displays the results and stores them in the database. The simulation experiments show that the average recognition accuracy of the deep local correlation neural network reaches 92.53%, compared with 87.21% of VGGNet and 88.50% of LSTM, and the accuracy rate is increased by 5.32% and 4.03%, respectively. The field test results show that the accuracy rate of the system can reach 91.43% in the field environment, and it can stably monitor the growth of farmland corn, which has important application value.
In order to accurately determine the growth stage of corn, remotely monitor the growth of corn and analyze the relationship between growth stage and field environment elements, this paper proposes a deep local correlation neural network to overcome the multimodal and fuzzy problems in the identification of corn growth stages. In the Oxford VGGNet (Visual Geometry Group Net) model, a new supervised layer, namely the local correlation loss layer, is added to improve the discriminating capability of deep features. Based on the proposed new image recognition algorithm for corn growth stages, the environmental element monitoring function is expanded, and a corn farmland monitoring system based on deep learning is designed. The system consists of a corn farmland monitoring device and a cloud server. The monitoring device collects corn images, meteorological elements and field location data, and sends them to the cloud server through a 4G wireless internet. The cloud server uses the deep local correlation neural network to identify the growth stages, and displays the results and stores them in the database. The simulation experiments show that the average recognition accuracy of the deep local correlation neural network reaches 92.53%, compared with 87.21% of VGGNet and 88.50% of LSTM, and the accuracy rate is increased by 5.32% and 4.03%, respectively. The field test results show that the accuracy rate of the system can reach 91.43% in the field environment, and it can stably monitor the growth of farmland corn, which has important application value.
2019, 47(4):581-591.
Abstract:
Beijing, is the fundamental requirement of the World Meteorological Organization (WMO) and Global DataProcessing and Forecasting System (GDPFS). WMCBeijing is responsible for providing stable, abundant, and highquality seamless weather analysis, forecast, and prediction products for other countries. In addition, it should also establish an international communication and exchange mechanism for weather forecast and prediction. To meet above needs, the WMCBeijing Global Forecast Service Share Platform is developed by the National Meteorological Center (NMC), which is developed based on the Brower/Server mode and realtime distributed computation to provide such functions as global observation, global GRAPES weather model, global BCC_CSM climate model, model verification data processing and analysis, automatical product flow, Web sharing and publishing, and international communication for weather forecast and prediction. This platform has been put into operation since 6 June 2018, which is a stable, easy and convenient meteorological Web platform used by more than 13 countries with 150 thousand visits. Through the professional weather monitoring and global forecasting, the platform will play as the belt connecting China with other countries.
Beijing, is the fundamental requirement of the World Meteorological Organization (WMO) and Global DataProcessing and Forecasting System (GDPFS). WMCBeijing is responsible for providing stable, abundant, and highquality seamless weather analysis, forecast, and prediction products for other countries. In addition, it should also establish an international communication and exchange mechanism for weather forecast and prediction. To meet above needs, the WMCBeijing Global Forecast Service Share Platform is developed by the National Meteorological Center (NMC), which is developed based on the Brower/Server mode and realtime distributed computation to provide such functions as global observation, global GRAPES weather model, global BCC_CSM climate model, model verification data processing and analysis, automatical product flow, Web sharing and publishing, and international communication for weather forecast and prediction. This platform has been put into operation since 6 June 2018, which is a stable, easy and convenient meteorological Web platform used by more than 13 countries with 150 thousand visits. Through the professional weather monitoring and global forecasting, the platform will play as the belt connecting China with other countries.
2019, 47(4):592-599.
Abstract:
In order to make full use of the powerful display and analysis ability of meteorological data in the MICAPS4 system, a application system for disastrous weather case database in Shanxi Province is designed under the framework of the .Net Framework 4.5, using the C# programming language, the MySQL database, and the secondary development interface provided by MICAPS4. The system achieves such functions as the management of historical case database, the retrieval and analysis of historical cases and cases similar to the model forecasting data, and the training and exam simulation of historical cases. At present, the system has been applied to forecasting operation. The system is not only scalable and easy to be localized, but also practical, so it has high application value. This paper describes the design, development, functions, and realization of the system in detail.
In order to make full use of the powerful display and analysis ability of meteorological data in the MICAPS4 system, a application system for disastrous weather case database in Shanxi Province is designed under the framework of the .Net Framework 4.5, using the C# programming language, the MySQL database, and the secondary development interface provided by MICAPS4. The system achieves such functions as the management of historical case database, the retrieval and analysis of historical cases and cases similar to the model forecasting data, and the training and exam simulation of historical cases. At present, the system has been applied to forecasting operation. The system is not only scalable and easy to be localized, but also practical, so it has high application value. This paper describes the design, development, functions, and realization of the system in detail.
2019, 47(4):600-607.
Abstract:
High winds，as a common weather phenomenon of significant influences，can be produced by various meteorological systems and orographic forcing. A comprehensive understanding of its mechanisms and forecast techniques is of great significance for wind disaster defense and wind energy utilization. This paper sorts out the standards of high winds both in weather forecasting service and meteorological observations， and the overall distribution of high winds including the major disastercausing systems such as thunderstorm， typhoon in China. Furthermore， the mechanisms of thunderstorm， typhoon and cold air，as well as the complex orographic thermal and dynamic effects on the formation of local high winds are briefly analyzed. Then， the research progresses in forecast techniques of different synoptic systems that generate high winds are summarized. Finally， the current status of high wind researches and important issues worth further research are discussed.
High winds，as a common weather phenomenon of significant influences，can be produced by various meteorological systems and orographic forcing. A comprehensive understanding of its mechanisms and forecast techniques is of great significance for wind disaster defense and wind energy utilization. This paper sorts out the standards of high winds both in weather forecasting service and meteorological observations， and the overall distribution of high winds including the major disastercausing systems such as thunderstorm， typhoon in China. Furthermore， the mechanisms of thunderstorm， typhoon and cold air，as well as the complex orographic thermal and dynamic effects on the formation of local high winds are briefly analyzed. Then， the research progresses in forecast techniques of different synoptic systems that generate high winds are summarized. Finally， the current status of high wind researches and important issues worth further research are discussed.
2019, 47(4):608-621.
Abstract:
Climate models are a powerful tool for studying the climate system and climate change, and the simulation results of climate models are an important data base for climate projection and risk evaluation of climate change. With the acceleration of global warming, the surface ecological environment, hydrological dynamic cycle and the development of social economy will be affected, which will also affect human safety. To evaluate and predict the future climate change features by using climate models can provide a scientific basis for adjusting human development strategies to adapt to climate change. The paper summarized domestic researches of the CMIP5 (Coupled Model Intercomparison Project Phase 5) global climate model in climate change, then summed up the application of the CMIP5 climate model in agricultural production, hydrologic dynamic monitoring and others. Finally, the paper points out the insufficiency of the CMIP5 climate model in the projection of climate change and prospects the future of the CMIP5 climate model.
Climate models are a powerful tool for studying the climate system and climate change, and the simulation results of climate models are an important data base for climate projection and risk evaluation of climate change. With the acceleration of global warming, the surface ecological environment, hydrological dynamic cycle and the development of social economy will be affected, which will also affect human safety. To evaluate and predict the future climate change features by using climate models can provide a scientific basis for adjusting human development strategies to adapt to climate change. The paper summarized domestic researches of the CMIP5 (Coupled Model Intercomparison Project Phase 5) global climate model in climate change, then summed up the application of the CMIP5 climate model in agricultural production, hydrologic dynamic monitoring and others. Finally, the paper points out the insufficiency of the CMIP5 climate model in the projection of climate change and prospects the future of the CMIP5 climate model.
2019, 47(4):622-630.
Abstract:
The prediction skills for climate models can be improved by using the statistical downscaling method. In order to gain better and objective midsummer precipitation prediction in Shanxi, a statistical downscaling method for the midsummer precipitation anomaly in Shanxi is studied based on BCC_CSM output, NCEP/NCAR reanalysis data, reconstructed sea surface temperature (SST) and station precipitation in Shanxi during 1990-2017. The typical anomalous patterns of midsummer precipitation in Shanxi are analyzed, and then predictors associated with SST from BCC_CSM output are identified in term of statistical significance to the typical anomalous patterns of midsummer precipitation in Shanxi. The multifactor stepwise regression is used in statistical downscaling prediction. The improvement of prediction skills in downscaling results are apparent, as measured by the temporal and spatial anomaly correlation coefficient (TCC and ACC), the prediction consistency of the anomaly sign (PC), and the prediction score (PS) between hindcasts and observations. TCC from downscaling results crosses the 95% significance threshold in most parts of Shanxi and exhibits 99% confidence level in the middlesouthern Shanxi, and the simulated precipitation from BCC_CSM shows too small value to reach statistical significance in Shanxi. ACC increases from -0.02 for BCC_CSM to 0.35 for downscaling results, and the corresponding PC and PS are improved from 53.3% to 66.8% and from 65.6% to 78.9%, respectively. In the operational midsummer precipitation prediction in 2018 by using above downscaling method, ACC is 0.42 and PS is 70.8%.
The prediction skills for climate models can be improved by using the statistical downscaling method. In order to gain better and objective midsummer precipitation prediction in Shanxi, a statistical downscaling method for the midsummer precipitation anomaly in Shanxi is studied based on BCC_CSM output, NCEP/NCAR reanalysis data, reconstructed sea surface temperature (SST) and station precipitation in Shanxi during 1990-2017. The typical anomalous patterns of midsummer precipitation in Shanxi are analyzed, and then predictors associated with SST from BCC_CSM output are identified in term of statistical significance to the typical anomalous patterns of midsummer precipitation in Shanxi. The multifactor stepwise regression is used in statistical downscaling prediction. The improvement of prediction skills in downscaling results are apparent, as measured by the temporal and spatial anomaly correlation coefficient (TCC and ACC), the prediction consistency of the anomaly sign (PC), and the prediction score (PS) between hindcasts and observations. TCC from downscaling results crosses the 95% significance threshold in most parts of Shanxi and exhibits 99% confidence level in the middlesouthern Shanxi, and the simulated precipitation from BCC_CSM shows too small value to reach statistical significance in Shanxi. ACC increases from -0.02 for BCC_CSM to 0.35 for downscaling results, and the corresponding PC and PS are improved from 53.3% to 66.8% and from 65.6% to 78.9%, respectively. In the operational midsummer precipitation prediction in 2018 by using above downscaling method, ACC is 0.42 and PS is 70.8%.
Sun Yinchuan
,
Zheng Guangfen
,
Wang Suyan
,
Li Xin
,
Zhang Wen
,
Yang Jianling
,
Zhu Xiaowei
,
Wang Fan
,
Gao Na
,
Gao Ruina
,
Ma Yang
2019, 47(4):631-638.
Abstract:
On the basis of the hindcast data of the National Climate Centre secondgeneration monthly Dynamic Extended Range Forecast operational system (DERF2.0) from 1983 to 2013 from 19 observed stations in Ningxia, the predicted precipitation is evaluated by operational methods in shortterm climate prediction. The results show: the monthly averaged PS (Propensity Score) of DEFR2.0 is 53.2%, and there is little difference among the results of 1 to 10 day lead times. But the forecast quality is unstable, with PS exceeding 60% only in the April and November, and the difference between best year and worst year is nearly 30%, reflecting the large interannual variability. DERF 2.0 has better performance in the lessrain months rather than in the morerain months, as well as in spring and autumn than rather summer. There is positive correlation between the predicted pentad precipitation by DERF2.0 with the lead time of less than 30 days and actual precipitation, the greatest in the first pentad and larger from September to March next year. The predicted pentad precipitation is about 30% larger than the actual precipitation. The accuracy of predicted precipitation trends of next 1 to 6 pentads is 40.8%.The accuracy is 79.5% in the pentads with more precipitation, which is obviously higher than in the pentads with less precipitation. The accuracy of trend prediction is the smallest in January and the largest in August. The accuracy of trend prediction in the pentads with more precipitation in winter is larger than that in summer and the accuracy of trend prediction in the pentads with less precipitation in summer is larger than that in winter. The trend prediction accuracy declines with the prolongation of lead time and increases from north to south. The prediction accuracy of persistent abnormal precipitation is 60.3% by DERF 2.0 with the lead time of 4 to 14 days. The better prediction effect is found for the whole regional precipitation process. The prediction accuracy in the southern part is greater than that in the northern part for the same process, and the predicted precipitation is less than actual precipitation.
On the basis of the hindcast data of the National Climate Centre secondgeneration monthly Dynamic Extended Range Forecast operational system (DERF2.0) from 1983 to 2013 from 19 observed stations in Ningxia, the predicted precipitation is evaluated by operational methods in shortterm climate prediction. The results show: the monthly averaged PS (Propensity Score) of DEFR2.0 is 53.2%, and there is little difference among the results of 1 to 10 day lead times. But the forecast quality is unstable, with PS exceeding 60% only in the April and November, and the difference between best year and worst year is nearly 30%, reflecting the large interannual variability. DERF 2.0 has better performance in the lessrain months rather than in the morerain months, as well as in spring and autumn than rather summer. There is positive correlation between the predicted pentad precipitation by DERF2.0 with the lead time of less than 30 days and actual precipitation, the greatest in the first pentad and larger from September to March next year. The predicted pentad precipitation is about 30% larger than the actual precipitation. The accuracy of predicted precipitation trends of next 1 to 6 pentads is 40.8%.The accuracy is 79.5% in the pentads with more precipitation, which is obviously higher than in the pentads with less precipitation. The accuracy of trend prediction is the smallest in January and the largest in August. The accuracy of trend prediction in the pentads with more precipitation in winter is larger than that in summer and the accuracy of trend prediction in the pentads with less precipitation in summer is larger than that in winter. The trend prediction accuracy declines with the prolongation of lead time and increases from north to south. The prediction accuracy of persistent abnormal precipitation is 60.3% by DERF 2.0 with the lead time of 4 to 14 days. The better prediction effect is found for the whole regional precipitation process. The prediction accuracy in the southern part is greater than that in the northern part for the same process, and the predicted precipitation is less than actual precipitation.
2019, 47(4):639-647.
Abstract:
This study uses the hourly insite data from the special observation station of Ba’nan District to conduct a comparative analysis of temperatures over different underlying surfaces (grass, soil, cobblestone, slate, concrete, and asphalt). The multiple timescale features of temperature difference between concrete and grass surfaces are assessed. The results show that the temperatures over different underlying surfaces show clear multiple timescale features. In monthly mean variation, the temperatures over slate, concrete and asphalt surfaces are higher than those over soil, grass and cobblestone surfaces. The difference is much bigger in summer and in the daytime. The extreme temperature of >45 ℃ is frequently occurred over slate, concrete and asphalt surfaces from 14:00 to 15:00 in the afternoon. The temperature differences between concrete and grass surfaces also show prominent seasonal and diurnal cycles. The differences are also larger in summer and in the daytime. The daily maximum values of the differences usually occur from 14:00 to 16:00 in the afternoon.
This study uses the hourly insite data from the special observation station of Ba’nan District to conduct a comparative analysis of temperatures over different underlying surfaces (grass, soil, cobblestone, slate, concrete, and asphalt). The multiple timescale features of temperature difference between concrete and grass surfaces are assessed. The results show that the temperatures over different underlying surfaces show clear multiple timescale features. In monthly mean variation, the temperatures over slate, concrete and asphalt surfaces are higher than those over soil, grass and cobblestone surfaces. The difference is much bigger in summer and in the daytime. The extreme temperature of >45 ℃ is frequently occurred over slate, concrete and asphalt surfaces from 14:00 to 15:00 in the afternoon. The temperature differences between concrete and grass surfaces also show prominent seasonal and diurnal cycles. The differences are also larger in summer and in the daytime. The daily maximum values of the differences usually occur from 14:00 to 16:00 in the afternoon.
13 Characteristic Analysis of Thunderstorms in Guangdong Based on Atmospheric Instability Parameters
2019, 47(4):648-654.
Abstract:
The thunderstorm strength from June to August in 2011, 2012 and 2014 is classified by using the data of lightning location in Qingyuan, Guangdong Province, combined with the radiosonde data, calculating some parameters that can reflect the stability or energy relationships of the atmosphere, such as the Convective Available Potential Energy, Showalter index and K index and so on. Then we analyze the distribution of these parameters before the occurrence of the different intensity thunderstorms in different time. The results show that the Showalter index, Lifted index, K index, Total Totals index, SWEAT index and Convective Available Potential Energy have a certain correlation with the intensity of thunderstorms, while Convective Inhibition, Bulk Richardson Number and the intensity of thunderstorms are not found to be well correlated. Among them, the Showalter index before the occurrence of thunderstorms in Guangdong is less than 0 ℃, the Lifted index less than -2 ℃, the K index greater than 30 ℃, and the Convective Available Potential Energy greater than 500 J/kg, which is more likely to produce moderate to strong thunderstorms. At the same time, the K index in Guangdong is about 20 ℃ higher than that in the Tibetan Plateau, and the average value of Convective Available Potential Energy is about 300 J/kg higher than those in the Tibetan Plateau and Shaanxi, Gansu, Ningxia. The distribution characteristics of other parameters are similar to those in some regions, which further reflect the particular characteristics of thunderstorms in Guangdong and help to understand the characteristics of thunderstorms in Guangdong.
The thunderstorm strength from June to August in 2011, 2012 and 2014 is classified by using the data of lightning location in Qingyuan, Guangdong Province, combined with the radiosonde data, calculating some parameters that can reflect the stability or energy relationships of the atmosphere, such as the Convective Available Potential Energy, Showalter index and K index and so on. Then we analyze the distribution of these parameters before the occurrence of the different intensity thunderstorms in different time. The results show that the Showalter index, Lifted index, K index, Total Totals index, SWEAT index and Convective Available Potential Energy have a certain correlation with the intensity of thunderstorms, while Convective Inhibition, Bulk Richardson Number and the intensity of thunderstorms are not found to be well correlated. Among them, the Showalter index before the occurrence of thunderstorms in Guangdong is less than 0 ℃, the Lifted index less than -2 ℃, the K index greater than 30 ℃, and the Convective Available Potential Energy greater than 500 J/kg, which is more likely to produce moderate to strong thunderstorms. At the same time, the K index in Guangdong is about 20 ℃ higher than that in the Tibetan Plateau, and the average value of Convective Available Potential Energy is about 300 J/kg higher than those in the Tibetan Plateau and Shaanxi, Gansu, Ningxia. The distribution characteristics of other parameters are similar to those in some regions, which further reflect the particular characteristics of thunderstorms in Guangdong and help to understand the characteristics of thunderstorms in Guangdong.
2019, 47(4):655-662.
Abstract:
By using the reanalysis grid data from 1980 to 2015 provided by NCEP/NCAR (National Centers for Environmental Prediction), the surface weather data of 80 stations in Guangxi, and the LambJenkinson atmospheric circulation classification method, we analyze the regular patterns of regional haze events and corresponding atmospheric circulation characteristics. The results show that the probability of hazes is the greatest while the circulation is the southeast wind type at the sealevel pressure field and west wind type at 500 hPa. The pattern with the east wind type at sealevel pressure field and the west wind type at 500 hPa makes the maximum contribution to the annual total hazes. The pattern of the southeast wind type at sea level and the west wind type at 500 hPa mainly occurs in spring, the transition period of cold air and warm air. The pattern of the cyclone type at sea level and the anticyclone type at 500 hPa mainly occurs in summer with the significantly strengthened western Pacific High and weak lowpressure on the ground. The pattern of the easterly type at sea level and west wind type at 500 hPa occurs in autumn with stable and straight circulation. The pattern of the easterly wind at sea level and anticyclone type at 500 hPa mainly occurs in winter with significantly increasing meridional circulation. The probability of hazes is the highest in winter, the lowest in summer. In the past 36 years, the haze contribution rate of east wind type at sea level and the anticyclone type at 500 hPa is increasing, which is the dominant circulation pattern for the trend of morethannormal hazes in the Guangxi.
By using the reanalysis grid data from 1980 to 2015 provided by NCEP/NCAR (National Centers for Environmental Prediction), the surface weather data of 80 stations in Guangxi, and the LambJenkinson atmospheric circulation classification method, we analyze the regular patterns of regional haze events and corresponding atmospheric circulation characteristics. The results show that the probability of hazes is the greatest while the circulation is the southeast wind type at the sealevel pressure field and west wind type at 500 hPa. The pattern with the east wind type at sealevel pressure field and the west wind type at 500 hPa makes the maximum contribution to the annual total hazes. The pattern of the southeast wind type at sea level and the west wind type at 500 hPa mainly occurs in spring, the transition period of cold air and warm air. The pattern of the cyclone type at sea level and the anticyclone type at 500 hPa mainly occurs in summer with the significantly strengthened western Pacific High and weak lowpressure on the ground. The pattern of the easterly type at sea level and west wind type at 500 hPa occurs in autumn with stable and straight circulation. The pattern of the easterly wind at sea level and anticyclone type at 500 hPa mainly occurs in winter with significantly increasing meridional circulation. The probability of hazes is the highest in winter, the lowest in summer. In the past 36 years, the haze contribution rate of east wind type at sea level and the anticyclone type at 500 hPa is increasing, which is the dominant circulation pattern for the trend of morethannormal hazes in the Guangxi.
2019, 47(4):663-672.
Abstract:
Using the AWS data of Hubei Province, conventional observation data and Doppler data, a downburst with gust fronts happened under the control of a subtropic high in the summer of 2017 is analyzed. The results indicate: (1) This downburst with a distinct gust front was caused by a pulse thunderstorm. (2) The interaction of topography and local thermal condition made the strong echo move to the southwest. (3) The gust front was very close to the echo at the beginning, so the strong echo made the local heavy precipitation last for a long time, and the strong downward flow and heavy precipitation led to a wide range of gale that mainly distributed near the front of the moving direction of the strong echo. (4) In the later stage, the gust front moved faster than the echo, so the echo weakened rapidly and the strong downward flow caused the ground gale. Then two gust fronts appeared and met each other. At this time, the gale mainly appeared at the intersection of the two gust fronts and the place with the strongest cold outflow of the thunderstorm. The conclusions can provide a useful reference to nowcasting.
Using the AWS data of Hubei Province, conventional observation data and Doppler data, a downburst with gust fronts happened under the control of a subtropic high in the summer of 2017 is analyzed. The results indicate: (1) This downburst with a distinct gust front was caused by a pulse thunderstorm. (2) The interaction of topography and local thermal condition made the strong echo move to the southwest. (3) The gust front was very close to the echo at the beginning, so the strong echo made the local heavy precipitation last for a long time, and the strong downward flow and heavy precipitation led to a wide range of gale that mainly distributed near the front of the moving direction of the strong echo. (4) In the later stage, the gust front moved faster than the echo, so the echo weakened rapidly and the strong downward flow caused the ground gale. Then two gust fronts appeared and met each other. At this time, the gale mainly appeared at the intersection of the two gust fronts and the place with the strongest cold outflow of the thunderstorm. The conclusions can provide a useful reference to nowcasting.
2019, 47(4):673-682.
Abstract:
Wire icing has a significant influence on the development of the national economy. We analyzed the temporal and spatial distribution of freezing rain and rime using the field observation data of 1276 sites from 1995 to 2017 in China. We divided the research region into two areas: the freezing rain area mainly in the southern China, such as YunnanGuizhou Plateau, Hunan and Jiangxi, and the rime area mainly in the northern China, such as the northern Henan,North China, the northern Xinjiang and Northeast China Plain. Freezing weather is mainly in winter, most of which happens in January. Based on suitable meteorological factor thresholds of freezing rain and rime, we improved the parameterized scheme of the Ramer algorithm, and used the ingredientsbased methodology to forecast rime. Comparing simulation and observation through a practical case, the missing forecast rate was significantly decreasing from 06 in original scheme to 0.31 in the improved scheme, and TS score which indicated the accuracy of the forecast increased sharply from 037 to 058.The range of rime simulation using the ingredientsbased methodology was highly consistent with observation of rime. It shows that this method has higher ability to forecast rime weather, which provides a new approach for the exploration of icing.
Wire icing has a significant influence on the development of the national economy. We analyzed the temporal and spatial distribution of freezing rain and rime using the field observation data of 1276 sites from 1995 to 2017 in China. We divided the research region into two areas: the freezing rain area mainly in the southern China, such as YunnanGuizhou Plateau, Hunan and Jiangxi, and the rime area mainly in the northern China, such as the northern Henan,North China, the northern Xinjiang and Northeast China Plain. Freezing weather is mainly in winter, most of which happens in January. Based on suitable meteorological factor thresholds of freezing rain and rime, we improved the parameterized scheme of the Ramer algorithm, and used the ingredientsbased methodology to forecast rime. Comparing simulation and observation through a practical case, the missing forecast rate was significantly decreasing from 06 in original scheme to 0.31 in the improved scheme, and TS score which indicated the accuracy of the forecast increased sharply from 037 to 058.The range of rime simulation using the ingredientsbased methodology was highly consistent with observation of rime. It shows that this method has higher ability to forecast rime weather, which provides a new approach for the exploration of icing.
17 Microstructure Analysis of Precipitating Stratiform Clouds at Dissipation Stage in Jilin Province
2019, 47(4):683-696.
Abstract:
Based on the cloud probe data of 2 air crafts (including DMT and PMS) carried out in Tongliao and Baicheng and radar data in 29 June 2012, the micro physical structure characteristics of a stratiform cloud precipitation at the dissipation stage in Jilin Province is discussed. The main results show that the weather process was developed under the influence of the Northeast frontal cyclone, brought a large range of precipitation to Northeast China, in which the clouds were the AsAcNs type, the common precipitation stratiform cloud system in spring in Jilin Province. The Nimbostratus base was about 1000 m and the top was not greater than 4000 m, and there were fractonimbuses under the nimbostratus, which was thicker during the development of the cloud system. Considering both DMT with PMS, small particles were accounted for the major part at each level, and the concentration of small particles with a 〖JP2〗diameter of 0.61 to 2 μm was 100 cm-3. The spectra of the particle with a diameter of larger than 2 μm was the monotone decreasing type. The cloud water content was less, and the maximum value was less than 0.01 g〖DK〗·m-3; 〖JP〗the effective diameter of particles varies with height in a multipeak distribution. The effective diameter of particles corresponded to the concentration of small particles under the 0 ℃ layer, and the effective diameter of large particles decreased with the increase of height.
Based on the cloud probe data of 2 air crafts (including DMT and PMS) carried out in Tongliao and Baicheng and radar data in 29 June 2012, the micro physical structure characteristics of a stratiform cloud precipitation at the dissipation stage in Jilin Province is discussed. The main results show that the weather process was developed under the influence of the Northeast frontal cyclone, brought a large range of precipitation to Northeast China, in which the clouds were the AsAcNs type, the common precipitation stratiform cloud system in spring in Jilin Province. The Nimbostratus base was about 1000 m and the top was not greater than 4000 m, and there were fractonimbuses under the nimbostratus, which was thicker during the development of the cloud system. Considering both DMT with PMS, small particles were accounted for the major part at each level, and the concentration of small particles with a 〖JP2〗diameter of 0.61 to 2 μm was 100 cm-3. The spectra of the particle with a diameter of larger than 2 μm was the monotone decreasing type. The cloud water content was less, and the maximum value was less than 0.01 g〖DK〗·m-3; 〖JP〗the effective diameter of particles varies with height in a multipeak distribution. The effective diameter of particles corresponded to the concentration of small particles under the 0 ℃ layer, and the effective diameter of large particles decreased with the increase of height.
2019, 47(4):697-704.
Abstract:
In this paper, the area rainfall of the lower reaches of Puli RIVER in the Three Gorges Reservoir area is calculated by using the Thiessen polygon and arithmetic average methods respectively. The results are input into the FloodArea model to simulate the same torrential flood process. The simulation results are compared and analyzed with the actual flooding time and depth. It turns out that in terms of the simulation of the torrential flood process, the depth of storm water simulated by the area rainfall data calculated by the Thiessen polygon method is closer to the actual data than that simulated by the area rainfall data obtained by the arithmetic mean method. Also, the former is more consistent with the actual situation than the latter. Further, the critical area rainfall calculated by the Thiessen polygon method is more valuable for application. This method can be used to calculate the critical area rainfall caused by mountain torrents.
In this paper, the area rainfall of the lower reaches of Puli RIVER in the Three Gorges Reservoir area is calculated by using the Thiessen polygon and arithmetic average methods respectively. The results are input into the FloodArea model to simulate the same torrential flood process. The simulation results are compared and analyzed with the actual flooding time and depth. It turns out that in terms of the simulation of the torrential flood process, the depth of storm water simulated by the area rainfall data calculated by the Thiessen polygon method is closer to the actual data than that simulated by the area rainfall data obtained by the arithmetic mean method. Also, the former is more consistent with the actual situation than the latter. Further, the critical area rainfall calculated by the Thiessen polygon method is more valuable for application. This method can be used to calculate the critical area rainfall caused by mountain torrents.
2019, 47(4):705-713.
Abstract:
The maximum allowable carryingcurrent capacity of overhead transmission lines highly depends on the meteorological parameters but traditionally the rigid and harsh setting of meteorological parameters makes the carryingcurrent capacity conservative. In order to make the carryingcurrent capacity setting satisfy the actual meteorological situation, this study utilizes the hourly data from 94 automatic meteorological stations over the southern Hebei to drive the wire energy balance equation for the analysis of carryingcurrent capacity. It helps to improve the transmission capacity of the transmission lines in the southern Hebei that the constant carryingcurrent capacity is changed into seasonally varied carryingcurrent capacity. Based on the analysis of the sensitivity of allowable maximum carryingcurrent capacity to the variation of ambient wind speed and air temperature, the study has determined the probability density distribution of ambient air temperature and wind speed, obtained the regional probability distribution of allowable maximum carryingcurrent capacity, and evaluated the transmission capacity at several safety operation levels. The results show that at the 95% safety operation level, the maximum carryingcurrent capacity of the LGJ400/35 transmission line in the southern Hebei can be set to 945, 774, 795 and 1012 A in spring, summer, autumn and winter, respectively, which is significantly higher than the traditional carryingcurrent capacity. Thus, currentcarrying capacity of the overhead transmission lines driven by actual meteorological data on the seasonal scales improves the transmission capacity of the lines.
The maximum allowable carryingcurrent capacity of overhead transmission lines highly depends on the meteorological parameters but traditionally the rigid and harsh setting of meteorological parameters makes the carryingcurrent capacity conservative. In order to make the carryingcurrent capacity setting satisfy the actual meteorological situation, this study utilizes the hourly data from 94 automatic meteorological stations over the southern Hebei to drive the wire energy balance equation for the analysis of carryingcurrent capacity. It helps to improve the transmission capacity of the transmission lines in the southern Hebei that the constant carryingcurrent capacity is changed into seasonally varied carryingcurrent capacity. Based on the analysis of the sensitivity of allowable maximum carryingcurrent capacity to the variation of ambient wind speed and air temperature, the study has determined the probability density distribution of ambient air temperature and wind speed, obtained the regional probability distribution of allowable maximum carryingcurrent capacity, and evaluated the transmission capacity at several safety operation levels. The results show that at the 95% safety operation level, the maximum carryingcurrent capacity of the LGJ400/35 transmission line in the southern Hebei can be set to 945, 774, 795 and 1012 A in spring, summer, autumn and winter, respectively, which is significantly higher than the traditional carryingcurrent capacity. Thus, currentcarrying capacity of the overhead transmission lines driven by actual meteorological data on the seasonal scales improves the transmission capacity of the lines.
2019, 47(4):714-718.
Abstract:
In view of the problem that the power supply of receiver, transmitter and servo system of CINRAD/CA of the new generation weather radar cannot be controlled remotely at present, a new weather radar remote control system based on PLC is established and implemented. Based on the Siemens S71200 PLC controller, the system indirectly controls the main circuit AC contactor by controlling the relay switch without changing the original structure of the radar, and without affecting the radar performance and technical indicators, to realize the realtime monitoring of the power supply operation state of the radar room receiver, transmitter and servo system, as well as the automatic control of the remote onekey switch. While ensuring the timeliness and availability of radar observation data transmission, the efficiency of radar technology support personnel for radar maintenance is improved, which can provide a reliable technical means for the unattended operation of the new generation weather radar observation stations.
In view of the problem that the power supply of receiver, transmitter and servo system of CINRAD/CA of the new generation weather radar cannot be controlled remotely at present, a new weather radar remote control system based on PLC is established and implemented. Based on the Siemens S71200 PLC controller, the system indirectly controls the main circuit AC contactor by controlling the relay switch without changing the original structure of the radar, and without affecting the radar performance and technical indicators, to realize the realtime monitoring of the power supply operation state of the radar room receiver, transmitter and servo system, as well as the automatic control of the remote onekey switch. While ensuring the timeliness and availability of radar observation data transmission, the efficiency of radar technology support personnel for radar maintenance is improved, which can provide a reliable technical means for the unattended operation of the new generation weather radar observation stations.
External LinksChina Meteorological AdministrationCMA Meteorological Observation CentreChinese Academy of Meteorological SciencesBeijing Meteorological ServiceNational Satellite Meteorological Center
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Supported by:Beijing E-Tiller Technology Development Co., Ltd.
Supported by:Beijing E-Tiller Technology Development Co., Ltd.