基于中尺度数值模式,对2020年7月9日~10日邵阳地区一次典型暴雨天气过程进行数值模拟,通过改变模式初始场中雪峰山地形高度敏感性试验,分析雪峰山地形对此次过程的动力场、水汽场、热力的演变特征,对雪峰山地形影响该地区降水机制进行...基于中尺度数值模式,对2020年7月9日~10日邵阳地区一次典型暴雨天气过程进行数值模拟,通过改变模式初始场中雪峰山地形高度敏感性试验,分析雪峰山地形对此次过程的动力场、水汽场、热力的演变特征,对雪峰山地形影响该地区降水机制进行讨论。结果表明:模式能较好地模拟出降水的强度和雨带的位置、强降水中心的位置、雨带的形状。地形敏感试验中,地形高度的改变,可以改变降水中心的强度和降水中心的位置。雪峰山地形的高度和陡度对气流的辐合均有重要的影响;相较于存在地形的区域,地形降低之后的辐合中心较为均匀。当地形下降时,水汽辐合区较明显减弱,雪峰山地形影响了水汽辐合的强度和位置,进而影响降水中心的分布。雪峰山地形有利于气流抬升,强的垂直上升运动中心在雪峰山的迎风坡和山顶附近较为显著,尤其是雪峰山崎岖地形陡度改变后,垂直上升运动中心位于其下游。Based on the mesoscale numerical model, a typical rainstorm weather process in Shaoyang from July 9 to 10, 2020 was numerically simulated. By changing the sensitivity test of Xuefeng Mountain terrain in the initial field of the model, the evolution characteristics of the dynamic field, water vapor field, and thermal force of Xuefeng Mountain terrain on this process were analyzed, and the precipitation mechanism of Xuefeng Mountain terrain in this region was discussed. The results indicate that the model can effectively simulate the intensity of precipitation, the location of rain bands, the position of heavy precipitation centers, and the shape of rain bands. In terrain sensitivity testing, changes in terrain height can alter the intensity and location of precipitation centers. The height and steepness of the terrain in Xuefeng Mountain have a significant impact on the convergence of airflow;Compared to areas with terrain, the convergence center after terrain reduction is more uniform. When the terrain descends, the water vapor convergence zone weakens significantly, and the terrain of Xuefeng Mountain affects the intensity and location of water vapor convergence, which in turn affects the distribution of precipitation centers. The terrain of Xuefeng Mountain is conducive to the uplift of air flow, and the strong vertical upward movement center is more significant near the windward slope and mountain top of Xuefeng Mountain, especially after the steep terrain of Xuefeng Mountain changes, the vertical upward movement center is located downstream.展开更多
利用WRF模式模拟发生在成都地区的典型雷暴天气过程,得到相应雷电活动过程中微物理和动力输出场,将其与雷电监测定位网所探测到的地闪资料进行对比分析,在电荷分离的微物理学基础上讨论了WRF(Weather Research and Forecasting)模式输...利用WRF模式模拟发生在成都地区的典型雷暴天气过程,得到相应雷电活动过程中微物理和动力输出场,将其与雷电监测定位网所探测到的地闪资料进行对比分析,在电荷分离的微物理学基础上讨论了WRF(Weather Research and Forecasting)模式输出的不同微物理及动力因子与地闪的相关性。结果表明:-10°C到-20°C之间的电荷分离区域内,冰晶粒子与霰粒子质量混合比最大值与地闪频数随时间变化趋势基本保持一致。在雷电活动中后期,霰、冰晶及雪晶粒子最大值位置与地闪密度大值中心位置对应性较好,空间上均能指示地闪发生区域。最大上升速度与风暴相对螺旋度可以指示地闪频数变化,风暴相对螺旋度空间上可指示地闪密度大值中心。模拟结果表明WRF模式微物理及动力输出场可以指示地闪活动的发生时间和位置,表现了日益成熟WRF模式进行雷电数值预报与研究的潜能。展开更多
2024年2月初,受持续性冷空气影响,湖南邵阳地区出现了较为罕见的持续性低温雨雪冰冻天气,邵阳市区和邵东48 h最低气温降幅达7.5℃以上,2月2日至7日全市平均气温0.9℃,较历年同期(6.5℃)偏低5.9℃。对EC模式预报产品检验分析发现,最新起...2024年2月初,受持续性冷空气影响,湖南邵阳地区出现了较为罕见的持续性低温雨雪冰冻天气,邵阳市区和邵东48 h最低气温降幅达7.5℃以上,2月2日至7日全市平均气温0.9℃,较历年同期(6.5℃)偏低5.9℃。对EC模式预报产品检验分析发现,最新起报时次的各层温度0线、逐3小时和逐6小时降雪量,对预报雨雪相态转换以及降雪落区具有很好的指示作用。在本轮过程中700 hPa 0℃线南压至邵阳是降水相态转为雪的重要经验指标,降水相态为冻雨时的850 hPa温度和地面温度低于雨夹雪。双偏振雷达CC、ZDR与KDP产品在本次低温雨雪过程中对降水相态的判定有较为明显的指示作用。In early February 2024, due to the continuous cold air, Shaoyang area in Hunan Province experienced a rare sustained low-temperature rain, snow, and freezing weather. The minimum temperature in Shaoyang city and Shaodong decreased by more than 7.5˚C in 48 hours. From February 2nd to 7th, the city’s average temperature was 0.9˚C, which was 5.9˚C lower than the same period in previous years (6.5˚C). The inspection and analysis of EC model forecast products found that the zero temperature line at each layer and the snowfall amount every 3 hours and 6 hours at the latest evening are good forecast indexes for forecasting the phase of rain and snow and the transformation of snowfall regions. In this round, the southward pressure of the 700 hPa 0˚C line to Shaoyang is an important empirical indicator for the transition of precipitation phase to snow. When the precipitation phase is freezing rain, the 850 hPa temperature and ground temperature are lower than those of sleet. The products of dual-polarization radar CC, ZDR and KDP have obvious indication function on the judgment of precipitation phase in the process of low temperature rain and snow weather.展开更多
利用湖南省32个观测站1960~2013年夏季降水资料和同期NCEP/NCAR提供的再分析资料,分析了湖南夏季降水的年代际变化,异常降水与500 hPa高度场、850 hPa风场、水汽收支的关系。结果表明:湖南夏季降水在1992年和2002年发生了突变;湖南地区...利用湖南省32个观测站1960~2013年夏季降水资料和同期NCEP/NCAR提供的再分析资料,分析了湖南夏季降水的年代际变化,异常降水与500 hPa高度场、850 hPa风场、水汽收支的关系。结果表明:湖南夏季降水在1992年和2002年发生了突变;湖南地区夏季降水异常偏少时,500 hPa中高纬地区高度场相对较平直,西太平洋副热带高压偏东偏弱,850 hPa上太平洋海区到华南一带出现大范围的气旋性环流异常,湖南为异常的东北气流控制。降水异常偏多年500 hPa中高纬西高东低形势明显,850 hPa北方为异常反气旋式环流,异常东北风会导致冷空气向南入侵。各边界流入、流出湖南水汽量的多寡会影响湖南夏季降水的多少;西风和南风水汽越强时越利于湖南降水,影响湖南净水汽量最主要的边界是南边界,南边界流入水汽的多少直接关系到湖南夏季降水的多少。Using the 32 observation stations in Hunan Province from 1960 to the summer of 2013 and the reanalysis data provided by NCEP/NCAR in the same period, analyzed the decadal variation of summer precipitation in Hunan Province, and the relationship between abnormal precipitation and 500 hPa height field, 850 hPa wind field, and water vapor balance was studied. The results show that: Hunan summer precipitation mutations occurred in 1992 and 2002;when the summer precipitation in Hunan region is abnormal, height field in the mid to high latitudes at 500 hPa is relatively flat, and the position of the western Pacific subtropical high is eastward and weak. There is a large-scale cyclonic circulation anomaly from the Pacific Ocean to southern China at 850 hPa, and Hunan is controlled by an abnormal northeast airflow. In years with abnormally high precipitation, the high latitudes at 500 hPa show a trend of being higher in the west and lower in the east. The northern part of 850 hPa has an abnormal anticyclonic circulation, and abnormal northeast winds can cause cold air to invade southward. The amount of water vapor flowing into and out of Hunan at each boundary will affect the amount of summer precipitation in Hunan;the stronger the west wind and south wind, the more favorable it is for precipitation in Hunan. The main boundary that affects the net water vapor in Hunan is the southern boundary, and the amount of water vapor flowing into the southern boundary directly affects the amount of summer precipitation in Hunan.展开更多
文摘基于中尺度数值模式,对2020年7月9日~10日邵阳地区一次典型暴雨天气过程进行数值模拟,通过改变模式初始场中雪峰山地形高度敏感性试验,分析雪峰山地形对此次过程的动力场、水汽场、热力的演变特征,对雪峰山地形影响该地区降水机制进行讨论。结果表明:模式能较好地模拟出降水的强度和雨带的位置、强降水中心的位置、雨带的形状。地形敏感试验中,地形高度的改变,可以改变降水中心的强度和降水中心的位置。雪峰山地形的高度和陡度对气流的辐合均有重要的影响;相较于存在地形的区域,地形降低之后的辐合中心较为均匀。当地形下降时,水汽辐合区较明显减弱,雪峰山地形影响了水汽辐合的强度和位置,进而影响降水中心的分布。雪峰山地形有利于气流抬升,强的垂直上升运动中心在雪峰山的迎风坡和山顶附近较为显著,尤其是雪峰山崎岖地形陡度改变后,垂直上升运动中心位于其下游。Based on the mesoscale numerical model, a typical rainstorm weather process in Shaoyang from July 9 to 10, 2020 was numerically simulated. By changing the sensitivity test of Xuefeng Mountain terrain in the initial field of the model, the evolution characteristics of the dynamic field, water vapor field, and thermal force of Xuefeng Mountain terrain on this process were analyzed, and the precipitation mechanism of Xuefeng Mountain terrain in this region was discussed. The results indicate that the model can effectively simulate the intensity of precipitation, the location of rain bands, the position of heavy precipitation centers, and the shape of rain bands. In terrain sensitivity testing, changes in terrain height can alter the intensity and location of precipitation centers. The height and steepness of the terrain in Xuefeng Mountain have a significant impact on the convergence of airflow;Compared to areas with terrain, the convergence center after terrain reduction is more uniform. When the terrain descends, the water vapor convergence zone weakens significantly, and the terrain of Xuefeng Mountain affects the intensity and location of water vapor convergence, which in turn affects the distribution of precipitation centers. The terrain of Xuefeng Mountain is conducive to the uplift of air flow, and the strong vertical upward movement center is more significant near the windward slope and mountain top of Xuefeng Mountain, especially after the steep terrain of Xuefeng Mountain changes, the vertical upward movement center is located downstream.
文摘利用WRF模式模拟发生在成都地区的典型雷暴天气过程,得到相应雷电活动过程中微物理和动力输出场,将其与雷电监测定位网所探测到的地闪资料进行对比分析,在电荷分离的微物理学基础上讨论了WRF(Weather Research and Forecasting)模式输出的不同微物理及动力因子与地闪的相关性。结果表明:-10°C到-20°C之间的电荷分离区域内,冰晶粒子与霰粒子质量混合比最大值与地闪频数随时间变化趋势基本保持一致。在雷电活动中后期,霰、冰晶及雪晶粒子最大值位置与地闪密度大值中心位置对应性较好,空间上均能指示地闪发生区域。最大上升速度与风暴相对螺旋度可以指示地闪频数变化,风暴相对螺旋度空间上可指示地闪密度大值中心。模拟结果表明WRF模式微物理及动力输出场可以指示地闪活动的发生时间和位置,表现了日益成熟WRF模式进行雷电数值预报与研究的潜能。
文摘2024年2月初,受持续性冷空气影响,湖南邵阳地区出现了较为罕见的持续性低温雨雪冰冻天气,邵阳市区和邵东48 h最低气温降幅达7.5℃以上,2月2日至7日全市平均气温0.9℃,较历年同期(6.5℃)偏低5.9℃。对EC模式预报产品检验分析发现,最新起报时次的各层温度0线、逐3小时和逐6小时降雪量,对预报雨雪相态转换以及降雪落区具有很好的指示作用。在本轮过程中700 hPa 0℃线南压至邵阳是降水相态转为雪的重要经验指标,降水相态为冻雨时的850 hPa温度和地面温度低于雨夹雪。双偏振雷达CC、ZDR与KDP产品在本次低温雨雪过程中对降水相态的判定有较为明显的指示作用。In early February 2024, due to the continuous cold air, Shaoyang area in Hunan Province experienced a rare sustained low-temperature rain, snow, and freezing weather. The minimum temperature in Shaoyang city and Shaodong decreased by more than 7.5˚C in 48 hours. From February 2nd to 7th, the city’s average temperature was 0.9˚C, which was 5.9˚C lower than the same period in previous years (6.5˚C). The inspection and analysis of EC model forecast products found that the zero temperature line at each layer and the snowfall amount every 3 hours and 6 hours at the latest evening are good forecast indexes for forecasting the phase of rain and snow and the transformation of snowfall regions. In this round, the southward pressure of the 700 hPa 0˚C line to Shaoyang is an important empirical indicator for the transition of precipitation phase to snow. When the precipitation phase is freezing rain, the 850 hPa temperature and ground temperature are lower than those of sleet. The products of dual-polarization radar CC, ZDR and KDP have obvious indication function on the judgment of precipitation phase in the process of low temperature rain and snow weather.
文摘利用湖南省32个观测站1960~2013年夏季降水资料和同期NCEP/NCAR提供的再分析资料,分析了湖南夏季降水的年代际变化,异常降水与500 hPa高度场、850 hPa风场、水汽收支的关系。结果表明:湖南夏季降水在1992年和2002年发生了突变;湖南地区夏季降水异常偏少时,500 hPa中高纬地区高度场相对较平直,西太平洋副热带高压偏东偏弱,850 hPa上太平洋海区到华南一带出现大范围的气旋性环流异常,湖南为异常的东北气流控制。降水异常偏多年500 hPa中高纬西高东低形势明显,850 hPa北方为异常反气旋式环流,异常东北风会导致冷空气向南入侵。各边界流入、流出湖南水汽量的多寡会影响湖南夏季降水的多少;西风和南风水汽越强时越利于湖南降水,影响湖南净水汽量最主要的边界是南边界,南边界流入水汽的多少直接关系到湖南夏季降水的多少。Using the 32 observation stations in Hunan Province from 1960 to the summer of 2013 and the reanalysis data provided by NCEP/NCAR in the same period, analyzed the decadal variation of summer precipitation in Hunan Province, and the relationship between abnormal precipitation and 500 hPa height field, 850 hPa wind field, and water vapor balance was studied. The results show that: Hunan summer precipitation mutations occurred in 1992 and 2002;when the summer precipitation in Hunan region is abnormal, height field in the mid to high latitudes at 500 hPa is relatively flat, and the position of the western Pacific subtropical high is eastward and weak. There is a large-scale cyclonic circulation anomaly from the Pacific Ocean to southern China at 850 hPa, and Hunan is controlled by an abnormal northeast airflow. In years with abnormally high precipitation, the high latitudes at 500 hPa show a trend of being higher in the west and lower in the east. The northern part of 850 hPa has an abnormal anticyclonic circulation, and abnormal northeast winds can cause cold air to invade southward. The amount of water vapor flowing into and out of Hunan at each boundary will affect the amount of summer precipitation in Hunan;the stronger the west wind and south wind, the more favorable it is for precipitation in Hunan. The main boundary that affects the net water vapor in Hunan is the southern boundary, and the amount of water vapor flowing into the southern boundary directly affects the amount of summer precipitation in Hunan.
