Mean Structure of Tropical Cyclones Making Landfall in Mainland China   总被引：2，自引：0，他引：2       下载免费PDF全文

BAI Lin  YU Hui  XU Yinglong  WANG Yuan 《Acta Meteorologica Sinica》2014,28(3):407-419

The mean kinematic and thermodynamic structures of tropical cyclones （TCs） making landfall in main-land China are examined by using sounding data from 1998 to 2009. It is found that TC landfall is usually accompanied with a decrease in low-level wind speed, an expansion of the radius of strong wind, weakening of the upper-level warm core, and drying of the mid-tropospheric air. On average, the warm core of the TCs dissipates 24 h after landfall. The height of the maximum low-level wind and the base of the stable layer both increase with the increased distance to the TC center;however, the former is always higher than the latter. In particular, an asymmetric structure of the TC after landfall is found. The kinematic and thermodynamic structures across various areas of TC circulation diff er, especially over the left-front and right-rear quadrants （relative to the direction of TC motion）. In the left-front quadrant, strong winds locate at a smaller radius, the upper-level temperature is warmer with the warm core extending into a deep layer, while the wet air occupies a shallow layer. In the right-rear quadrant, strong wind and wet air dwell in an area that is broader and deeper, and the warmest air is situated farther away from the TC center.  相似文献   

Weather extremes and street life in India—Implications of Fuzzy Cognitive Mapping as a new tool for semi-quantitative impact assessment and ranking of adaptation measures     

《Global Environmental Change》2014

The potential impacts of progressing climate change are alarming. Some adverse consequences are now unavoidable and adaptation measures are increasingly needful. This poses enormous challenges for emerging megacities in the Global South, which barely manage in current weather conditions. This paper introduces Fuzzy Cognitive Mapping as a new tool for structured, semi-quantitative assessments of climate change impacts and adaptation measures.Fuzzy Cognitive Mapping is used to evaluate differences in sensitivities to heatwaves and rainstorms across socio-economic groups and for the ranking of useful adaptation options, based on 188 individual interviews to the impacts of extreme weather events in Hyderabad, India. The results of this multi-stakeholder assessment indicate that rainstorms affect low-income residents more than heatwaves, while the opposite is true for medium-income respondents. The latter are also less seriously affected by extreme weather in general. Profession, though, not income determines the kind of impact that people feel most affected by. Individual characteristics like age and gender do not significantly explain differences in the data, but religion does. This is because, in Hyderabad, Muslims live in the older, less serviced and more affected parts of the city. However, semi-quantitative scenario analyses suggest that, under future climate change, many parts of the city will become increasingly exposed to the effects of extreme weather. Planned investments in urban infrastructure will be seriously challenged by climate change and preventive adaptation measures are urgently needed to at least maintain the current level of quality of life. Investments in the health infrastructure appear to be most effective in reducing the impact of heatwaves and investments in the traffic infrastructure most effective in reducing the impact of rainstorms. However, looking at heat and rain events together—which is realistic as they are both projected to increase and often occur in the same year—reveals that investments in water infrastructure and management have greatest potential to reduce impacts across all localities and on all social groups, particularly the lower-income classes. This is because first-order impacts caused by inadequate water infrastructure often give rise to second- or third-order impacts. Addressing the root cause is the most effective way to break cause-and-effect chains and prevent proliferation of negative consequences. Similar studies are suggested in other cities in order to support adaptation mainstreaming in complex urban environments. Fuzzy Cognitive Mapping proved a useful, semi-quantitative tool for climate change impact and adaptation assessments.  相似文献   

“等熵思维”到“等熵位涡思维”回顾与讨论   总被引：3，自引：0，他引：3  

周小刚  王秀明  陶祖钰 《气象》2014,40(5):521-529

等熵位涡守恒与中纬度斜压扰动发展之间的诊断关系可用于对气旋发生发展的预报,并作为理解水汽图像的动力学场而在业务上使用。"等熵位涡思维"建立在等熵面分析的"等熵思维"基础上。本文首先依据基础的动力学理论,对等熵面上物理量场的动力学解释和业务应用作回顾和讨论,内容包括:等熵面随高度分布特征、等熵坐标中的垂直速度场、等熵面上水汽输送解释、等熵面上高空急流和锋区的特征等。其次,通过与等熵面物理量场分析和斜压二层模式准地转垂直运动方程的比较,着重回顾和讨论等熵位涡面上的物理量场和业务应用,内容包括:对流层顶定义及其温压湿分布特征、对流层顶等熵位涡面上急流和锋区的特征、对流层顶等熵位涡面上的垂直速度场、"等熵位涡思维"与气旋发展及位涡、水汽图像在改进数值预报模式中的作用等。  相似文献   

2014年7月大气环流和天气分析   总被引：5，自引：2，他引：3  

唐健  代刊 《气象》2014,40(10):1286-1292

提2014年7月环流特征如下：北半球高纬地区为单一极涡,中高纬地区呈5波型分布,巴尔喀什湖附近低槽和东亚大槽强度均较常年偏强;西北太平洋副热带高压带呈东西带状分布,强度与常年同期相当。7月全国平均降水量115．0 mm,较常年同期（120．6 mm）偏少4．6％;全国平均气温为22．3℃,较常年同期（21．9℃）偏高0．4℃。月内共出现8次强降水过程,多站出现极端日降水量。7月共有5个热带气旋（风力8级以上）在西北太平洋和南海活动,生成个数较常年偏多,并有“威马逊”、“麦德姆”2个热带气旋登陆。华南、江南等地出现持续高温天气,全国87个气象观测站发生极端高温事件,74站发生极端日降水量事件。  相似文献   

雷电定位系统与人工观测雷暴日数统计比较   总被引：3，自引：0，他引：3       下载免费PDF全文

王学良  张科杰  张义军  朱传林 《应用气象学报》2014,25(6):741-750

为了利用雷电定位系统 (lightning location system,LLS) 资料统计人工观测雷暴日数,采用湖北省2007—2012年LLS监测资料,选取25个气象站为圆心,统计其不同监测半径 (r) 圆区域内LLS监测的雷电日数,并与人工观测雷暴日数进行比较。结果表明:r≤7 km时,LLS监测平均年雷电日数小于人工观测平均年雷暴日数;r≥8 km时, LLS监测平均年雷电日数大于人工观测平均年雷暴日数;r=22 km圆区域内年平均雷电日数可替代最大年雷暴日数。根据r=7 km,r=8 km圆区域内LLS监测的年雷电日数、年平均地闪密度资料,分别采用直接替代法、地闪密度法和该文提出的二元法计算年雷暴日数,结果显示:二元法效果最好。二元法计算的2007—2012年25个站平均年雷暴日数与人工观测相等,平均差异为7.4%;二元法计算的2013年年雷暴日数与人工观测相差0.8 d,平均差异为12.3%。  相似文献   

2013年南疆2场罕见暴雨落区和强度的对比分析     

张俊兰  魏荣庆  杨柳 《沙漠与绿洲气象(新疆气象)》2014,8(5):1-9

2013年5月26～28日和6月15～18日南疆连续出现了2场罕见的暴雨过程,利用常规地面和高空探测资料、NCEP/NCAR每日4时次 1°×1°再分析资料和欧洲ECWMF 0.25°×0.25°细网格数值预报产品,对比分析了这2场暴雨的落区和强度差异的成因。2场暴雨均在有利的环流背景下产生,较强暴雨的高空环流经向度更大、中亚低槽与北支槽打通并南伸更南,低层700hPa以下水汽输送较中高层更为重要,日常预报更应注重低层的水汽输入。对比暴雨强度,低层水汽输送越强(更多水汽路径、更多边界的水汽输入、更强水汽通量和水汽输入量)、低层水汽输送时间越长、低层切变线持续时间长且伸展至中高层,暴雨强度均可能更强。中尺度切变线和涌线在暴雨落区预报中具有一定的指示意义。  相似文献   

一次华北气旋造成北京特大暴雪天气过程分析     

詹正杰  尹仔锋  乔林  赵玮  孙秀忠 《沙漠与绿洲气象(新疆气象)》2014,8(5):10-15

利用北京延庆站和海淀站风廓线产品、微波辐射计产品、北京市雷达产品(南郊和车道沟)、北京市58个称重雨量站观测资料、FY-2E卫星云图、常规气象资料综合分析2012年11月3到4日北京暴雪天气过程。分析表明：降水相态(雨、雪)由华北气旋的锋面性质和锋面位置决定;过程雨雪量由气旋的强度、持续时间和水汽通道维持时间决定;风廓线和微波辐射计产品资料在雨雪开始时间、雨雪相态转换方面有明显的指示性作用。  相似文献   

昌吉站迁站对气象要素影响及热岛强度指标分析     

王金风 《沙漠与绿洲气象(新疆气象)》2014,8(5):58-62

选取昌吉站旧址1981—2013年（其中1981—2008年为迁站前昌吉站资料,2009—2013年为旧址作为区域站Y5522所采集资料）、新址2009—2013年资料进行对比分析,并对新旧站址资料进行T检验,结果表明：迁站前后,新址与旧址气温、相对湿度、风速变化趋势基本一致,但变化幅度新址较旧址略大。两站气温差冬季变化最为明显,夏季变化最小;平均相对湿度新址较旧址偏高,各季差值在冬季最小;平均风速较旧址偏大0.9 m/s,最多风向新址为西风及西南风,旧址为西风;从年平均值的连续性看,年平均气温、年平均最低气温、年平均相对湿度连续性较差,年平均最高气温与年平均风速连续性相对较好。  相似文献   

我国东南沿海午后短时降水极端峰值强度与湿度和地表气温的关联   总被引：1，自引：0，他引：1       下载免费PDF全文

孙溦  原韦华  李建  宇如聪 《热带气象学报》2014,30(5):932-940

利用中国东南沿海地区55个站点的逐时降水、日平均地面温湿场、低空气温露点差及OISST海表温度资料,对午后短时降水的极端峰值强度与湿度和地表气温的关联进行分析。结果表明,东南沿海地区午后短时降水极端峰值强度随气温的变化趋势存在明显变化,日最高气温低于29℃时,峰值强度随气温升高而上升;日最高气温高于29℃时,峰值强度随气温升高而下降。分析水汽条件作用发现,峰值强度在高温条件下随气温的升高而下降的现象与相对湿度变化有关,日最高气温较高时,相对湿度随气温的升高而大幅减小。初步分析可知,当陆地达到较高温度并进一步增温时,附近海域海表温度变化不大,使得洋面水汽含量增加较少。在陆地水汽主要来自于海洋的情况下,伴随陆地的进一步升温,地表相对湿度将减小。  相似文献   

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������  ������  �ŷ� 《大地测量与地球动力学》2014,34(6):37-40

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