Debris flow prediction is one of the important means to reduce the loss caused by debris flow. This paper built a regional prediction model of impending debris flow based on regional environmental background （includi...Debris flow prediction is one of the important means to reduce the loss caused by debris flow. This paper built a regional prediction model of impending debris flow based on regional environmental background （including topography, geology, land use, and etc.）, rainfall and debris flow data. A system of regional prediction of impending debris flow was set up on ArcGIS 9.0 platform according to the model. The system used forecast precipitation data of Doppler weather radar and observational precipitation data as its input data. It could provide a prediction about the possibility of debris flow one to three hours before it happened, and was put into use in Liangshan Meteorological Observatory in Sichuan province in the monsoon of 2006.展开更多
Wind shear reflects that the wind field is not uniform, which is one of the primary factors which make the retrieval of the wind field difficult. Based on volume velocity process(VVP) wind field retrieval technique, t...Wind shear reflects that the wind field is not uniform, which is one of the primary factors which make the retrieval of the wind field difficult. Based on volume velocity process(VVP) wind field retrieval technique, the intensity of wind shear is identified in this paper. After analyzing the traditional techniques that rely on the difference of radial velocity to identify wind shear, a fixed difference among radial velocities that may cause false identification in a uniform wind field was found. Because of the non-uniformity in wind shear areas, the difference of retrieved results between surrounding analysis volumes can be used as a measurement to show how strong the wind shear is. According to the analysis of a severe convective weather process that occurred in Guangzhou, it can be found that the areas of wind shear appeared with the strength significantly larger than in other regions and the magnitude generally larger than4.5 m/(s·km). Besides, by comparing the variation of wind shear strength during the convection, it can be found that new cells will be more likely to generate when the strength is above 3.0 m/(s·km). Therefore, the analysis of strong wind shear's movement and development is helpful to forecasting severe convections.展开更多
New generation Doppler weather radar (NEXTRAD) has become one of the most important tools for monitoring and forecasting severe weather. It has been widely used in some developed countries. The construction of China’...New generation Doppler weather radar (NEXTRAD) has become one of the most important tools for monitoring and forecasting severe weather. It has been widely used in some developed countries. The construction of China’s NEXTRAD network has started since 1998, and this project is supported by national debt. In this paper the author addresses the development of NEXTRAD techniques, the pre\|sent situation of construction and application of NEXTRAD in China, some problems to be carefully considered in construction, and seve\|ral new fields of future radar technique developments and applications in weather monitoring.展开更多
Using single Doppler weather radar echo information, this paper presents a technique for recognizing two-di- mensional flow field structure of the severe storm and estimating the divergence, the vorticity, and the int...Using single Doppler weather radar echo information, this paper presents a technique for recognizing two-di- mensional flow field structure of the severe storm and estimating the divergence, the vorticity, and the intensity of wind shear line, and gives some examples.展开更多
By using Doppler weather radar data,the meso-scale characteristics of extremely heavy rainstorm process which happened suddenly in Jieyang urban area on July 31,2008 were analyzed.The results showed that the radar ech...By using Doppler weather radar data,the meso-scale characteristics of extremely heavy rainstorm process which happened suddenly in Jieyang urban area on July 31,2008 were analyzed.The results showed that the radar echo only needed 20 minutes from the generation to the strong echo which quickly strengthened above 50 dBz.The storm center went down south and went up north near Jieyang City all the time.The component which moved eastward was very tiny,and the heavy precipitation echo stagnated.In this heavy precipitation process,the characteristics types of radial velocity which were favorable to the generation and development of heavy precipitation echo appeared alternately each other.The radial velocity's characteristics types were the first type headwind zone,the second type headwind zone,meso-scale convergence type and cyclonic convergence and so on.Thus,this heavy precipitation process which broke the record happened.The analyses showed that the headwind zone which developed vigorously and the convergence which had influx and outflux airflow in the vertical direction of headwind zone made obvious contributions to the precipitation.展开更多
A three-dimensional wind field analysis sollware based on the Beigng-Gucheng dual-Doppler weather radar system has been built, and evaluated by using the numerical cloud model producing storm flow and hydrometeor fiel...A three-dimensional wind field analysis sollware based on the Beigng-Gucheng dual-Doppler weather radar system has been built, and evaluated by using the numerical cloud model producing storm flow and hydrometeor fields. The effects of observation noise and the spatial distribution of wind field analysis error are also investigated.展开更多
This work presents the climatology of the microphysics and the dynamics of weather systems in two coastal areas of São Paulo and the Espírito States at high spatial-temporal resolution as measured by two...This work presents the climatology of the microphysics and the dynamics of weather systems in two coastal areas of São Paulo and the Espírito States at high spatial-temporal resolution as measured by two dual Doppler weather radars during the summer and early fall of 2015. Averages and respective standard deviations of polarimetric variables, namely, reflectivity (Z), differential reflectivity (Z<sub>DR</sub>), differential phase (ϕ<sub>DP</sub>), specific differential phase (K<sub>DP</sub>), copolar correlation coefficient (ρ<sub>oHV</sub>), radial velocity (V<sub>r</sub>), and the spectral width (W) were obtained within a 240-km range on plan position indicator (PPI), constant altitude plan position indicator (CAPPI) and vertical cross-sections to analyze overall horizontal and vertical precipitation microphysics and mesoscale circulation of prevailing weather systems, and their peculiarities over coastal and oceanic, and urban and rural areas. Overall, raindrops tend to be larger over the Metropolitan area of São Paulo from the surface to up to 6 km altitude indicating more vigorous updrafts caused by the heat island effect and the local sea breeze. The vertical microphysical structure is remarkably distinct over the Metropolitan Area of São Paulo (MASP) where thunderstorms can reach 20-km altitude in summertime under sea breeze and heat island effects. On the other hand, there is a dominancy of smaller drop sizes though larger ones observed close to the surface by the coast of Espírito Santo and at the land-ocean interface influenced by the local low-level jet and oceanic-type CCN. Convective cells tend to be smaller associated with Easterlies and more organized with Westerlies. The results indicate distinct features on hydrometeor types and circulation characteristics under these different surface and boundary-layer conditions in close agreement with previous results in the literature.展开更多
Doppler radar have become one of the most important instruments for weather now casting,and for meso-scale weather research because of its higher spatial and temporal resolutions. A dealing system for Doppler radar gr...Doppler radar have become one of the most important instruments for weather now casting,and for meso-scale weather research because of its higher spatial and temporal resolutions. A dealing system for Doppler radar graphic was researched and implemented so as to providing a convenient tool for users. We research and realized CINRAD/XD Doppler radar's graphic system. It contains three important parts:reading,standardization and pretreatment. It can be used very easily and conveniently. Besides,the system can be expanded and transplanted simply.展开更多
This paper describes the procedure and methodology to formulate the convective weather potential （CWP） algorithm. The data used in the development of the algorithm are the radar echoes at 0.5° elevation from Gu...This paper describes the procedure and methodology to formulate the convective weather potential （CWP） algorithm. The data used in the development of the algorithm are the radar echoes at 0.5° elevation from Guangzhou Doppler Radar Station, surface observations from automatic weather stations （AWS） and outputs of numeric weather prediction （NWP） models. The procedure to develop the CWP algorithm consists of two steps： （1） identification of thunderstorm cells in accordance with specified statistical criteria; and （2） development of the algorithm based on multiple linear regression. The thunderstorm cells were automatically identified by radar echoes with intensity greater than or equal to 50 dB（Z） and of an area over 64 square kilometers. These cells are generally related to severe convective weather occurrences such as thunderstorm wind gusts, hail and tornados. In the development of the CWP algorithm, both echo- and environment-based predictors are used. The predictand is the probability of a thunderstorm cell to generate severe convective weather events. The predictor-predictand relationship is established through a stepwise multiple linear regression approach. Verification with an independent dataset shows that the CWP algorithm is skillful in detecting thunderstorm-related severe convective weather occurrences in the Pearl River Delta （PRD） region of South China. An example of a nowcasting case for a thunderstorm process is illustrated.展开更多
基金the Knowledge Innovation Program of Chinese Academy Sciences (KZX3-SW-352)Frontier Program of Institute of Mountain Hazards and Environment, CAS (C3200307)
文摘Debris flow prediction is one of the important means to reduce the loss caused by debris flow. This paper built a regional prediction model of impending debris flow based on regional environmental background （including topography, geology, land use, and etc.）, rainfall and debris flow data. A system of regional prediction of impending debris flow was set up on ArcGIS 9.0 platform according to the model. The system used forecast precipitation data of Doppler weather radar and observational precipitation data as its input data. It could provide a prediction about the possibility of debris flow one to three hours before it happened, and was put into use in Liangshan Meteorological Observatory in Sichuan province in the monsoon of 2006.
基金Qinghai province key laboratory open fund of disaster prevention and reduction(QHKF201401)Key technology projects of China Meteorological Bureau(CMAGJ2014M21)+3 种基金National Natural Science Fund(41675029,41401504,41671425,41565008)Key Scientific Research Projects in Colleges and Universities(17A170005)China Postdoctoral Fund(2016M602232)Foundation of Henan University(2015YBZR020)
文摘Wind shear reflects that the wind field is not uniform, which is one of the primary factors which make the retrieval of the wind field difficult. Based on volume velocity process(VVP) wind field retrieval technique, the intensity of wind shear is identified in this paper. After analyzing the traditional techniques that rely on the difference of radial velocity to identify wind shear, a fixed difference among radial velocities that may cause false identification in a uniform wind field was found. Because of the non-uniformity in wind shear areas, the difference of retrieved results between surrounding analysis volumes can be used as a measurement to show how strong the wind shear is. According to the analysis of a severe convective weather process that occurred in Guangzhou, it can be found that the areas of wind shear appeared with the strength significantly larger than in other regions and the magnitude generally larger than4.5 m/(s·km). Besides, by comparing the variation of wind shear strength during the convection, it can be found that new cells will be more likely to generate when the strength is above 3.0 m/(s·km). Therefore, the analysis of strong wind shear's movement and development is helpful to forecasting severe convections.
文摘New generation Doppler weather radar (NEXTRAD) has become one of the most important tools for monitoring and forecasting severe weather. It has been widely used in some developed countries. The construction of China’s NEXTRAD network has started since 1998, and this project is supported by national debt. In this paper the author addresses the development of NEXTRAD techniques, the pre\|sent situation of construction and application of NEXTRAD in China, some problems to be carefully considered in construction, and seve\|ral new fields of future radar technique developments and applications in weather monitoring.
文摘Using single Doppler weather radar echo information, this paper presents a technique for recognizing two-di- mensional flow field structure of the severe storm and estimating the divergence, the vorticity, and the intensity of wind shear line, and gives some examples.
基金Supported by The State Natural Science Fund Project(40875025, 40875030,40775033)Shanghai Natural Science Fund Project (08ZR1422900)
文摘By using Doppler weather radar data,the meso-scale characteristics of extremely heavy rainstorm process which happened suddenly in Jieyang urban area on July 31,2008 were analyzed.The results showed that the radar echo only needed 20 minutes from the generation to the strong echo which quickly strengthened above 50 dBz.The storm center went down south and went up north near Jieyang City all the time.The component which moved eastward was very tiny,and the heavy precipitation echo stagnated.In this heavy precipitation process,the characteristics types of radial velocity which were favorable to the generation and development of heavy precipitation echo appeared alternately each other.The radial velocity's characteristics types were the first type headwind zone,the second type headwind zone,meso-scale convergence type and cyclonic convergence and so on.Thus,this heavy precipitation process which broke the record happened.The analyses showed that the headwind zone which developed vigorously and the convergence which had influx and outflux airflow in the vertical direction of headwind zone made obvious contributions to the precipitation.
文摘A three-dimensional wind field analysis sollware based on the Beigng-Gucheng dual-Doppler weather radar system has been built, and evaluated by using the numerical cloud model producing storm flow and hydrometeor fields. The effects of observation noise and the spatial distribution of wind field analysis error are also investigated.
文摘This work presents the climatology of the microphysics and the dynamics of weather systems in two coastal areas of São Paulo and the Espírito States at high spatial-temporal resolution as measured by two dual Doppler weather radars during the summer and early fall of 2015. Averages and respective standard deviations of polarimetric variables, namely, reflectivity (Z), differential reflectivity (Z<sub>DR</sub>), differential phase (ϕ<sub>DP</sub>), specific differential phase (K<sub>DP</sub>), copolar correlation coefficient (ρ<sub>oHV</sub>), radial velocity (V<sub>r</sub>), and the spectral width (W) were obtained within a 240-km range on plan position indicator (PPI), constant altitude plan position indicator (CAPPI) and vertical cross-sections to analyze overall horizontal and vertical precipitation microphysics and mesoscale circulation of prevailing weather systems, and their peculiarities over coastal and oceanic, and urban and rural areas. Overall, raindrops tend to be larger over the Metropolitan area of São Paulo from the surface to up to 6 km altitude indicating more vigorous updrafts caused by the heat island effect and the local sea breeze. The vertical microphysical structure is remarkably distinct over the Metropolitan Area of São Paulo (MASP) where thunderstorms can reach 20-km altitude in summertime under sea breeze and heat island effects. On the other hand, there is a dominancy of smaller drop sizes though larger ones observed close to the surface by the coast of Espírito Santo and at the land-ocean interface influenced by the local low-level jet and oceanic-type CCN. Convective cells tend to be smaller associated with Easterlies and more organized with Westerlies. The results indicate distinct features on hydrometeor types and circulation characteristics under these different surface and boundary-layer conditions in close agreement with previous results in the literature.
基金The important science and technology itemof Jiangsu province.(BR2004012)
文摘Doppler radar have become one of the most important instruments for weather now casting,and for meso-scale weather research because of its higher spatial and temporal resolutions. A dealing system for Doppler radar graphic was researched and implemented so as to providing a convenient tool for users. We research and realized CINRAD/XD Doppler radar's graphic system. It contains three important parts:reading,standardization and pretreatment. It can be used very easily and conveniently. Besides,the system can be expanded and transplanted simply.
文摘This paper describes the procedure and methodology to formulate the convective weather potential （CWP） algorithm. The data used in the development of the algorithm are the radar echoes at 0.5° elevation from Guangzhou Doppler Radar Station, surface observations from automatic weather stations （AWS） and outputs of numeric weather prediction （NWP） models. The procedure to develop the CWP algorithm consists of two steps： （1） identification of thunderstorm cells in accordance with specified statistical criteria; and （2） development of the algorithm based on multiple linear regression. The thunderstorm cells were automatically identified by radar echoes with intensity greater than or equal to 50 dB（Z） and of an area over 64 square kilometers. These cells are generally related to severe convective weather occurrences such as thunderstorm wind gusts, hail and tornados. In the development of the CWP algorithm, both echo- and environment-based predictors are used. The predictand is the probability of a thunderstorm cell to generate severe convective weather events. The predictor-predictand relationship is established through a stepwise multiple linear regression approach. Verification with an independent dataset shows that the CWP algorithm is skillful in detecting thunderstorm-related severe convective weather occurrences in the Pearl River Delta （PRD） region of South China. An example of a nowcasting case for a thunderstorm process is illustrated.
