A new technique for identifying regional climate events, the Objective Identification Technique for Regional Extreme Events（OITREE）, was applied to investigate the characteristics of regional heavy rainfall events i...A new technique for identifying regional climate events, the Objective Identification Technique for Regional Extreme Events（OITREE）, was applied to investigate the characteristics of regional heavy rainfall events in China during the period1961–2012. In total, 373 regional heavy rainfall events（RHREs） were identified during the past 52 years. The East Asian summer monsoon（EASM） had an important influence on the annual variations of China＇s RHRE activities, with a significant relationship between the intensity of the RHREs and the intensity of the Mei-yu. Although the increase in the frequency of those RHREs was not significant, China experienced more severe and extreme regional rainfall events in the 1990 s. The middle and lower reaches of the Yangtze River and the northern part of South China were the regions in the country most susceptible to extreme precipitation events. Some stations showed significant increasing trends in the southern part of the middle and lower reaches of the Yangtze River and the northern part of South China, while parts of North China, regions between Guangxi and Guangdong, and northern Sichuan showed decreasing trends in the accumulated intensity of RHREs.The spatial distribution of the linear trends of events＇ accumulated intensity displayed a similar so-called ＂southern flooding and northern drought＂ pattern over eastern China in recent decades.展开更多
Using GPS precipitable water vapor( GPS-PWV) inverted based on the advanced ZHD model and localized T_m model,as well as hourly meteorological data from automatic weather station,the variation characteristics of atmos...Using GPS precipitable water vapor( GPS-PWV) inverted based on the advanced ZHD model and localized T_m model,as well as hourly meteorological data from automatic weather station,the variation characteristics of atmospheric water vapor and evolution features of GPS-PWV during 14 heavy rainfall events at Huaihua in 2017 were analyzed. As the results shown,GPS-PWV could reveal the variation characteristics of atmospheric water vapor in Huaihua region well. The monthly change of precipitable water vapor-pressure( PWV-P) data pair was evident. The PWV appeared a lower value with a smaller range accompanied by a 14.75 hPa higher surface air pressure than that in summer when precipitation occurred during winter,which gradually increased with a lower surface air pressure while precipitation occurred during spring. In summer,the PWV rose to the annual peak value with the lowest surface air pressure under rainfall,and it scattered to low-value area in autumn. In 14 heavy rainfall events at Huaihua during flood season of 2017,all of the PWV values exceeded corresponding monthly mean,besides there was a well corresponded relationship between the maximum rainfall and the maximum PWV in hourly scale. Before the heavy rainfall occurred,the PWV increased comparatively distinctly with a clear decrease of the surface air pressure,and that could be a preferably reference point in the local strong precipitation nowcasting.展开更多
This study delves into the multiple weather systems and their interaction mechanisms that caused the severe rainfall event in Northeast China in early August 2023. The analysis reveals that the atmospheric circulation...This study delves into the multiple weather systems and their interaction mechanisms that caused the severe rainfall event in Northeast China in early August 2023. The analysis reveals that the atmospheric circulation in the mid-to-high latitudes of the Eurasian continent exhibited a significant “two troughs and two ridges” structure, with Northeast China located precisely in the peripheral region of the subtropical high, significantly influenced by its marginal airflows. Additionally, the residual circulation of Typhoon “Doksuri” interacting with the subtropical high and upper-level troughs significantly increased the rainfall intensity and duration in the region. In particular, the continuous and powerful transport of the southwest jet provided the necessary moisture and unstable conditions for the generation and development of convective systems. The rainfall event resulted in nearly 40,000 people affected and crop damage covering an area of approximately 4000 hectares, demonstrating the severity of extreme weather. The study emphasizes that strengthening meteorological monitoring and early warning systems, as well as formulating and improving emergency response mechanisms, are crucial for reducing potential disaster losses caused by heavy rainfall. Future research can further explore the interaction mechanisms among weather systems, limitations of data sources, and the connection between long-term trends of heavy rainfall events and global climate change.展开更多
相较于暴雨这种日尺度强降水,短时强降水(≥20 mm h^(−1))是造成山洪滑坡与城市内涝等灾害更为直接的因素。本文利用地面气象观测站和ERA5再分析数据,重点研究南海季风爆发前后珠江三角洲地区(简称珠三角)短时强降水的时空演变特征,并...相较于暴雨这种日尺度强降水,短时强降水(≥20 mm h^(−1))是造成山洪滑坡与城市内涝等灾害更为直接的因素。本文利用地面气象观测站和ERA5再分析数据,重点研究南海季风爆发前后珠江三角洲地区(简称珠三角)短时强降水的时空演变特征,并探索了短时强降水在季风爆发前后特征差异的可能成因。研究表明:(1)相较于季风爆发前,珠三角地区季风爆发后的降水明显增多,其中短时强降水贡献的比例显著增加。对短时强降水本身而言,区域平均强度以及极端性在季风爆发前后差异总体较小,但短时强降水频率在季风爆发后增加70%。(2)短时强降水高发区主要集中在珠三角东北部和珠江口西侧沿海,季风爆发后上述两个地区的频次增多最明显。短时强降水频率由季风爆发前的单峰型(下午)转为季风爆发后的双峰型(早晨与下午)。(3)短时强降水具有明显的区域性变化特征,短时强降水在季风爆发后的平均雨强和极端性在珠江口西侧沿海较内陆地区明显增强,其频次峰值时间在沿海地区从季风爆发前的午后转为季风爆发后的早晨,内陆地区在季风爆发前后均集中在下午。(4)季风爆发后,短时强降水期间的低层环境水汽超过同期气候态水平的16%。充沛的水汽在夜间在季风加速作用下被输送至沿海,并与陆风作用增强了辐合,这解释了沿海短时强降水的在季风爆发前后频次峰值时间转换现象。(5)相较于季风爆发前,季风爆发后珠三角短时强降水频率与低层水汽通量的相关性明显升高。珠三角沿海地区夜间—早晨短时强降水的增多与中低层风场结构改变造成的动力强迫有关。内陆地区季风爆发前后短时强降水与环境热力和不稳定条件关系更大。这些结果有助于我们更好地了解珠三角地区在季风爆发前后短时强降水的时空分布特征和理解其产生机制。展开更多
The heavy rainfall in the summer of 1998 over China has been simulated with the NCC Regional Climate Model(RegCM_NCC).It was successful for RegCM_NCC to reproduce the location and seasonal shift of the seasonal rain b...The heavy rainfall in the summer of 1998 over China has been simulated with the NCC Regional Climate Model(RegCM_NCC).It was successful for RegCM_NCC to reproduce the location and seasonal shift of the seasonal rain belt in the summer of 1998 over China.The rainy season in the summer of 1998 over China can be divided into 7 episodes,including the pre-summer rainy season in South China.the Meiyu onset over the Yangtze-Huaihe River Basin,short appearance of North China rain season and the retreat of seasonal rain belt,the second Meiyu season over the Yangtze River Valley,the rainy period over the Yellow and Huaihe River Valley and the seasonal retreat of rain belt over North China.The shortcoming of the RegCM_NCC is over-estimation of precipitation amounts.The regions with large latent heat flux,upper soil moisture and total runoff are located in the rainy area and move with the simulated rain belt during the different episodes.On the contrary,the regions with small sensible heat flux are located in the simulated rainy area and move with the simulated rain belt during the different episodes.展开更多
Atmospheric winds from observations and medium-range weather forecast model predictions can be physically decomposed as daily climate wind,planetary-scale anomalous wind,and synoptic-scale anomalous wind.The 850 hPa s...Atmospheric winds from observations and medium-range weather forecast model predictions can be physically decomposed as daily climate wind,planetary-scale anomalous wind,and synoptic-scale anomalous wind.The 850 hPa synoptic-scale anomalous winds were extracted from the numerical model outputs of the European Centre for Medium-Range Weather Forecasts(ECMWF) and the NCEP Global Forecast System(GFS).The results showed that most rain bands in eastern China in 2010 were located along the anomalous convergence lines.To predict the major rain bands by these convergence lines in 2010,the accuracies of the ECMWF products were 100%,85%,and 15% for leading 3,6,and 9 days,while the GFS products showed 53%,15%,and 6% accuracies,respectively.In comparison of the regional heavy rainfalls between observation and the ECMWF model prediction,the useful leading information was about 3.1 days for direct model rain prediction and 6.7 days for convergence systems predicted by ECMWF model.展开更多
基金supported jointly by the National Natural Science Foundation of China (Grant No. 41175075)the Major State Basic Research Development Program of China (973 program) (Grant No. 2010CB950501)
文摘A new technique for identifying regional climate events, the Objective Identification Technique for Regional Extreme Events（OITREE）, was applied to investigate the characteristics of regional heavy rainfall events in China during the period1961–2012. In total, 373 regional heavy rainfall events（RHREs） were identified during the past 52 years. The East Asian summer monsoon（EASM） had an important influence on the annual variations of China＇s RHRE activities, with a significant relationship between the intensity of the RHREs and the intensity of the Mei-yu. Although the increase in the frequency of those RHREs was not significant, China experienced more severe and extreme regional rainfall events in the 1990 s. The middle and lower reaches of the Yangtze River and the northern part of South China were the regions in the country most susceptible to extreme precipitation events. Some stations showed significant increasing trends in the southern part of the middle and lower reaches of the Yangtze River and the northern part of South China, while parts of North China, regions between Guangxi and Guangdong, and northern Sichuan showed decreasing trends in the accumulated intensity of RHREs.The spatial distribution of the linear trends of events＇ accumulated intensity displayed a similar so-called ＂southern flooding and northern drought＂ pattern over eastern China in recent decades.
基金Supported by the Scientific Research Project of Hunan Meteorological Bureau(XQKJ16B038XQKJ17B099)。
文摘Using GPS precipitable water vapor( GPS-PWV) inverted based on the advanced ZHD model and localized T_m model,as well as hourly meteorological data from automatic weather station,the variation characteristics of atmospheric water vapor and evolution features of GPS-PWV during 14 heavy rainfall events at Huaihua in 2017 were analyzed. As the results shown,GPS-PWV could reveal the variation characteristics of atmospheric water vapor in Huaihua region well. The monthly change of precipitable water vapor-pressure( PWV-P) data pair was evident. The PWV appeared a lower value with a smaller range accompanied by a 14.75 hPa higher surface air pressure than that in summer when precipitation occurred during winter,which gradually increased with a lower surface air pressure while precipitation occurred during spring. In summer,the PWV rose to the annual peak value with the lowest surface air pressure under rainfall,and it scattered to low-value area in autumn. In 14 heavy rainfall events at Huaihua during flood season of 2017,all of the PWV values exceeded corresponding monthly mean,besides there was a well corresponded relationship between the maximum rainfall and the maximum PWV in hourly scale. Before the heavy rainfall occurred,the PWV increased comparatively distinctly with a clear decrease of the surface air pressure,and that could be a preferably reference point in the local strong precipitation nowcasting.
文摘This study delves into the multiple weather systems and their interaction mechanisms that caused the severe rainfall event in Northeast China in early August 2023. The analysis reveals that the atmospheric circulation in the mid-to-high latitudes of the Eurasian continent exhibited a significant “two troughs and two ridges” structure, with Northeast China located precisely in the peripheral region of the subtropical high, significantly influenced by its marginal airflows. Additionally, the residual circulation of Typhoon “Doksuri” interacting with the subtropical high and upper-level troughs significantly increased the rainfall intensity and duration in the region. In particular, the continuous and powerful transport of the southwest jet provided the necessary moisture and unstable conditions for the generation and development of convective systems. The rainfall event resulted in nearly 40,000 people affected and crop damage covering an area of approximately 4000 hectares, demonstrating the severity of extreme weather. The study emphasizes that strengthening meteorological monitoring and early warning systems, as well as formulating and improving emergency response mechanisms, are crucial for reducing potential disaster losses caused by heavy rainfall. Future research can further explore the interaction mechanisms among weather systems, limitations of data sources, and the connection between long-term trends of heavy rainfall events and global climate change.
文摘相较于暴雨这种日尺度强降水,短时强降水(≥20 mm h^(−1))是造成山洪滑坡与城市内涝等灾害更为直接的因素。本文利用地面气象观测站和ERA5再分析数据,重点研究南海季风爆发前后珠江三角洲地区(简称珠三角)短时强降水的时空演变特征,并探索了短时强降水在季风爆发前后特征差异的可能成因。研究表明:(1)相较于季风爆发前,珠三角地区季风爆发后的降水明显增多,其中短时强降水贡献的比例显著增加。对短时强降水本身而言,区域平均强度以及极端性在季风爆发前后差异总体较小,但短时强降水频率在季风爆发后增加70%。(2)短时强降水高发区主要集中在珠三角东北部和珠江口西侧沿海,季风爆发后上述两个地区的频次增多最明显。短时强降水频率由季风爆发前的单峰型(下午)转为季风爆发后的双峰型(早晨与下午)。(3)短时强降水具有明显的区域性变化特征,短时强降水在季风爆发后的平均雨强和极端性在珠江口西侧沿海较内陆地区明显增强,其频次峰值时间在沿海地区从季风爆发前的午后转为季风爆发后的早晨,内陆地区在季风爆发前后均集中在下午。(4)季风爆发后,短时强降水期间的低层环境水汽超过同期气候态水平的16%。充沛的水汽在夜间在季风加速作用下被输送至沿海,并与陆风作用增强了辐合,这解释了沿海短时强降水的在季风爆发前后频次峰值时间转换现象。(5)相较于季风爆发前,季风爆发后珠三角短时强降水频率与低层水汽通量的相关性明显升高。珠三角沿海地区夜间—早晨短时强降水的增多与中低层风场结构改变造成的动力强迫有关。内陆地区季风爆发前后短时强降水与环境热力和不稳定条件关系更大。这些结果有助于我们更好地了解珠三角地区在季风爆发前后短时强降水的时空分布特征和理解其产生机制。
基金"National Key Program for Developing Basic Sciences"G1998040900 the National Natural Science Foundation of China(No.49794030).
文摘The heavy rainfall in the summer of 1998 over China has been simulated with the NCC Regional Climate Model(RegCM_NCC).It was successful for RegCM_NCC to reproduce the location and seasonal shift of the seasonal rain belt in the summer of 1998 over China.The rainy season in the summer of 1998 over China can be divided into 7 episodes,including the pre-summer rainy season in South China.the Meiyu onset over the Yangtze-Huaihe River Basin,short appearance of North China rain season and the retreat of seasonal rain belt,the second Meiyu season over the Yangtze River Valley,the rainy period over the Yellow and Huaihe River Valley and the seasonal retreat of rain belt over North China.The shortcoming of the RegCM_NCC is over-estimation of precipitation amounts.The regions with large latent heat flux,upper soil moisture and total runoff are located in the rainy area and move with the simulated rain belt during the different episodes.On the contrary,the regions with small sensible heat flux are located in the simulated rainy area and move with the simulated rain belt during the different episodes.
基金supported by the R&D Special Fund for Public Welfare Industry (Meteorology) (Grant No. GYHY201306013)
文摘Atmospheric winds from observations and medium-range weather forecast model predictions can be physically decomposed as daily climate wind,planetary-scale anomalous wind,and synoptic-scale anomalous wind.The 850 hPa synoptic-scale anomalous winds were extracted from the numerical model outputs of the European Centre for Medium-Range Weather Forecasts(ECMWF) and the NCEP Global Forecast System(GFS).The results showed that most rain bands in eastern China in 2010 were located along the anomalous convergence lines.To predict the major rain bands by these convergence lines in 2010,the accuracies of the ECMWF products were 100%,85%,and 15% for leading 3,6,and 9 days,while the GFS products showed 53%,15%,and 6% accuracies,respectively.In comparison of the regional heavy rainfalls between observation and the ECMWF model prediction,the useful leading information was about 3.1 days for direct model rain prediction and 6.7 days for convergence systems predicted by ECMWF model.
文摘利用2008—2016年6-8月黑龙江省844个自动雨量站资料,采用了多级判别法、一元线性回归、平均值显著性检验、配料等方法统计黑龙江省311天的2 154个站次短时强降水的时空分布特征;再利用常规气象资料、NECP的1°×1°再分析资料总结这些短时强降水在对流层中层500 h Pa和地面主要影响系统。分析结果表明:黑龙江省短时强降水日数和站次都与本年6-8月全省总平均降水量成线性关系,相关性分别为0.841和0.917;按照区域尺度划分的局地性、区域性和大范围短时强降水中,在强降水日数和分布上依次减小和不均,在强降水站次和连续性上依次增加;2008年和2013年分别为短时强降水最少和最多的年份;局地性和区域性短时强降水分别在7月上、下旬为达到峰值,大范围短时强降水在6月上、中旬分布很少,8月下旬没有,其它时间均匀分布;由于受太阳辐射,下垫面影响,午后12~19时是强降水高发期,14~15时达到站次最高值,1~4时为站次最低值;短时强降水主要分布在海拔为100~200 m的西南地区,北部地区分布较少;北部和东南部部分地区没有大范围短时强降水产生;多项数据表明太阳辐射导致的非绝热加热为强降水特别是局地强降水带来巨大贡献;高空低值系统与地面锋面共同影响是产生短时强降水及增加降水面积的主要影响系统;由于受降水性质和系统发生频率以及水汽和热力等条件影响,受高空槽前配合地面暖锋影响比例最大。
