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
Observed rainfall is a very essential parameter for the analysis of rainfall,day to day weather forecast and its validation.The observed rainfall data is only available from five observatories of IMD;while no rainfall...Observed rainfall is a very essential parameter for the analysis of rainfall,day to day weather forecast and its validation.The observed rainfall data is only available from five observatories of IMD;while no rainfall data is available at various important locations in and around Delhi-NCR.However,the 24-hour rainfall data observed by Doppler Weather Radar(DWR)for entire Delhi and surrounding region(up to 150 km)is readily available in a pictorial form.In this paper,efforts have been made to derive/estimate the rainfall at desired locations using DWR hydrological products.Firstly,the rainfall at desired locations has been estimated from the precipitation accumulation product(PAC)of the DWR using image processing in Python language.After this,a linear regression model using the least square method has been developed in R language.Estimated and observed rainfall data of year 2018(July,August and September)was used to train the model.After this,the model was tested on rainfall data of year 2019(July,August and September)and validated.With the use of linear regression model,the error in mean rainfall estimation reduced by 46.58% and the error in max rainfall estimation reduced by 84.53% for the year 2019.The error in mean rainfall estimation reduced by 81.36% and the error in max rainfall estimation reduced by 33.81%for the year 2018.Thus,the rainfall can be estimated with a fair degree of accuracy at desired locations within the range of the Doppler Weather Radar using the radar rainfall products and the developed linear regression model.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
[Objective] The research aimed to analyze an easterly wave thunderstorm and gale weather during the latter flood season of 2010.[Method] Based on conventional observation data,data of automatic station,NCEP 1°...[Objective] The research aimed to analyze an easterly wave thunderstorm and gale weather during the latter flood season of 2010.[Method] Based on conventional observation data,data of automatic station,NCEP 1°×1° reanalysis data,Doppler radar reflectivity and radial velocity data,the easterly wave thunderstorm and gale weather process which happened during 4-5 August,2010 was analyzed.The circulation situation,wind field and dynamic & thermal structures of easterly wave,echo characteristics of Doppler radar when thunderstorm and gale happened were studied.[Result] The thunderstorm and gale weather happened in the northeaster zone in front of the deep thick easterly wave trough.When thunderstorm and gale weather happened,position of the subtropical high was by north(ridge line was at 35° N).Eastward movement of the north branch of trough compelled subtropical high splitting into east and west circles.Westward extension of the east subtropical high and saddle-type field circulation were favorable for generation and development of the easterly wave.As development and westward movement of the easterly wave,in the influence zone in front of the trough,upper easterly component transmitted downward.Then,low-level northeaster obviously strengthened,and thunderstorm and gale weather appeared.In the zone where thunderstorm and gale happened,airflow had cyclonic convergence at the middle and low layers and anti-cyclonic divergence near the ground layer.Subsidence movement was obvious.Moreover,thermal force structure that it tended to be dry and cold at the middle and high layers,warm and wet at the low layer existed.Supercell storm was at the developed stage on 4th.It had obvious mesocyclone and hooked echo characteristics(meso-and small-scale characteristics).Characteristics of the squall line,gale region and adverse wind region appeared in central west Guangdong on 5th.Doppler characteristics of the mesocyclone,hooked echo,squall line,gale region and adverse wind region had indication significance for short-imminent forecast of the thunderstorm and gale.[Conclusion] This research revealed some information which had significance for forecasting local easterly wave thunderstorm and gale weather.展开更多
为了监测预警极端短时强降水的发生,减少极端短时强降水造成的灾害,基于降水资料、天气图、雷达拼图、雷达PUP产品等资料和技术分析方法,对2023-08-27 T 20:00/2023-08-28 T 20:00乐平港边极端短时强降水事件进行分析,结果表明:强降水...为了监测预警极端短时强降水的发生,减少极端短时强降水造成的灾害,基于降水资料、天气图、雷达拼图、雷达PUP产品等资料和技术分析方法,对2023-08-27 T 20:00/2023-08-28 T 20:00乐平港边极端短时强降水事件进行分析,结果表明:强降水由丰城、南昌至景德镇东北-西南向的中尺度雨带造成,其中乐平中部港边24 h雨量达195.8 mm,小时最大雨强达102.8 mm,为2023年景德镇地区强降水之最;强降水与闪电密切相关,最强降水时段闪电最为密集;强降水与强劲的副热带高压阻挡有关,回波东移受阻,移动缓慢,冷暖空气较长时间对峙、交汇,前倾槽、低层辐合、高层辐散与充沛的水汽供应导致极端强降水;强降水由较大范围35~45 dBZ回波中伴有少量45~50 dBZ的絮状强回波造成,其间回波稳定少动、合并,单部雷达上表现为中等强度垂直累积液态水含量、垂直的柱状结构、低质心、正负速度辐合等特征。研究结果为极端短时强降水的临近预报提供了参考依据。展开更多
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Observed rainfall is a very essential parameter for the analysis of rainfall,day to day weather forecast and its validation.The observed rainfall data is only available from five observatories of IMD;while no rainfall data is available at various important locations in and around Delhi-NCR.However,the 24-hour rainfall data observed by Doppler Weather Radar(DWR)for entire Delhi and surrounding region(up to 150 km)is readily available in a pictorial form.In this paper,efforts have been made to derive/estimate the rainfall at desired locations using DWR hydrological products.Firstly,the rainfall at desired locations has been estimated from the precipitation accumulation product(PAC)of the DWR using image processing in Python language.After this,a linear regression model using the least square method has been developed in R language.Estimated and observed rainfall data of year 2018(July,August and September)was used to train the model.After this,the model was tested on rainfall data of year 2019(July,August and September)and validated.With the use of linear regression model,the error in mean rainfall estimation reduced by 46.58% and the error in max rainfall estimation reduced by 84.53% for the year 2019.The error in mean rainfall estimation reduced by 81.36% and the error in max rainfall estimation reduced by 33.81%for the year 2018.Thus,the rainfall can be estimated with a fair degree of accuracy at desired locations within the range of the Doppler Weather Radar using the radar rainfall products and the developed linear regression model.
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[Objective] The research aimed to analyze an easterly wave thunderstorm and gale weather during the latter flood season of 2010.[Method] Based on conventional observation data,data of automatic station,NCEP 1°×1° reanalysis data,Doppler radar reflectivity and radial velocity data,the easterly wave thunderstorm and gale weather process which happened during 4-5 August,2010 was analyzed.The circulation situation,wind field and dynamic & thermal structures of easterly wave,echo characteristics of Doppler radar when thunderstorm and gale happened were studied.[Result] The thunderstorm and gale weather happened in the northeaster zone in front of the deep thick easterly wave trough.When thunderstorm and gale weather happened,position of the subtropical high was by north(ridge line was at 35° N).Eastward movement of the north branch of trough compelled subtropical high splitting into east and west circles.Westward extension of the east subtropical high and saddle-type field circulation were favorable for generation and development of the easterly wave.As development and westward movement of the easterly wave,in the influence zone in front of the trough,upper easterly component transmitted downward.Then,low-level northeaster obviously strengthened,and thunderstorm and gale weather appeared.In the zone where thunderstorm and gale happened,airflow had cyclonic convergence at the middle and low layers and anti-cyclonic divergence near the ground layer.Subsidence movement was obvious.Moreover,thermal force structure that it tended to be dry and cold at the middle and high layers,warm and wet at the low layer existed.Supercell storm was at the developed stage on 4th.It had obvious mesocyclone and hooked echo characteristics(meso-and small-scale characteristics).Characteristics of the squall line,gale region and adverse wind region appeared in central west Guangdong on 5th.Doppler characteristics of the mesocyclone,hooked echo,squall line,gale region and adverse wind region had indication significance for short-imminent forecast of the thunderstorm and gale.[Conclusion] This research revealed some information which had significance for forecasting local easterly wave thunderstorm and gale weather.
文摘为了监测预警极端短时强降水的发生,减少极端短时强降水造成的灾害,基于降水资料、天气图、雷达拼图、雷达PUP产品等资料和技术分析方法,对2023-08-27 T 20:00/2023-08-28 T 20:00乐平港边极端短时强降水事件进行分析,结果表明:强降水由丰城、南昌至景德镇东北-西南向的中尺度雨带造成,其中乐平中部港边24 h雨量达195.8 mm,小时最大雨强达102.8 mm,为2023年景德镇地区强降水之最;强降水与闪电密切相关,最强降水时段闪电最为密集;强降水与强劲的副热带高压阻挡有关,回波东移受阻,移动缓慢,冷暖空气较长时间对峙、交汇,前倾槽、低层辐合、高层辐散与充沛的水汽供应导致极端强降水;强降水由较大范围35~45 dBZ回波中伴有少量45~50 dBZ的絮状强回波造成,其间回波稳定少动、合并,单部雷达上表现为中等强度垂直累积液态水含量、垂直的柱状结构、低质心、正负速度辐合等特征。研究结果为极端短时强降水的临近预报提供了参考依据。
