“98·5”华南前汛期暴雨的湿位涡异常诊断:质量和热力强迫的数值分析   总被引：3，自引：1，他引：2       下载免费PDF全文

文莉娟  程麟生  左洪超  隆霄 《热带气象学报》2006,22(5):447-453

利用MM5输出的高分辨率资料对“98．5”华南暴雨的湿位涡进行了诊断分析，分析了质量强迫和热力强迫引起的湿位涡异常。结果揭示：降水区位于负湿位涡的下方，负湿位涡的趋势走向与降水区的一致。造成本次暴雨的成因中包括湿对称不稳定和对流不稳定两种机制，湿位涡MPV（moist potential vorticity）的分量MPV2对MPV起主要作用，其中主要是MPV2v的贡献。质量强迫和热力强迫共同作用引起湿位涡异常变化，它们的作用大小相当，在研究暴雨时，不可忽略因降水造成的质量强迫。  相似文献   

伊犁河流域气候资源特点及其时空分布规律研究   总被引：5，自引：0，他引：5  

张军民 《甘肃气象》2006,24(2):1-4

三面环山向西开敞的地形使伊犁河流域冬季虽受蒙古高压控制,但少有寒流侵袭;夏季虽受副热带低压笼罩,但干热气流难以深入,形成了温和湿润的气候基调。伊犁河流域光热资源充分,尤以降水充沛而成为新疆及亚洲中部干旱区的“湿岛”。由西向东,从河谷盆地到丘陵山地,伊犁河流域气候类型及组合呈现出明显的地域性分布规律,以草原、荒漠草原为主的河谷气候和以森林、森林草原为主的山地气候孕育了伊犁河流域优良的气候特点和多样的气候资源。  相似文献   

Fluctuations of the Semi-Arid Zone in China, and Consequences for Society     

Jianping Yang  Yongjian Ding  Rensheng Chen  Lianyou Liu 《Climatic change》2005,72(1-2):171-188

Herein, we calculate an aridity index, D, based on annual precipitation, P, and measured evaporation, PET, from φ20 evaporation pans: D = P/PET. The data were collected between 1951 and 1999 at 295 meteorological stations operated by the Chinese Meteorological Administration. On the basis of the index, three climatic regions are recognized in China: an arid zone in which D ≤ 0.20, a semi-arid zone with 0.20 < D ≤ 0.50, and a humid zone in which D > 0.50. Temporal fluctuations of the climate boundaries are substantial, and differ significantly regionally, and have the shifting features in the same direction in some areas and in opposite directions in others over the past 50 years. The semiarid zone lies along the border of the monsoon, and is thus highly susceptible to environmental change in China. In the period from the late 1960s to the early 1970s, the climate became drier in most parts of the regions of northern China. Moreover, the drought has an increasing trend. The fluctuations of climatic boundaries and the alternation from drier to wetter climate have substantial inter-decadal features. The main factors affecting the fluctuations in climate boundaries are the East Asian summer monsoon, the Indian Monsoon, the plateau monsoon in Tibetan Plateau, the westerly circulation, and the West Pacific Subtropical High. The different types of circulation and the strength of these circulations result in regional and temporal differences in aridity. Inter-decadal variations of the dry- and wet climate boundary fluctuations and of the arid and humid climate result from the inter-decadal changes of East Asian summer monsoon, Indian Monsoon, plateau monsoon, westerly circulation, and West Pacific Subtropical High. The anomalous general atmospheric circulation in the Northern Hemisphere during the late 1960s to the early 1970s is the cause of the remarkable change in arid and humid climate in China. Major natural disasters produced by arid and humid change are drought and flood disasters. They cause enormous economic losses to agriculture and industry. Furthermore, the loss has a substantial increasing trend. More than 110 cities are in severe water-deficiency conditions because of shortage of water resource in China. Drought has been a limiting factor of economic and social development in China.  相似文献   

青藏高原及铁路沿线未来50年气候变化的模拟分析   总被引：6，自引：2，他引：4  

徐影  赵宗慈  李栋梁 《高原气象》2005,24(5):700-707

利用由IPCC数据分发中心（DDC）提供的5个全球海气耦合模式（包括海冰与陆地生态系统）（CCCma，CCSR，CSIRO，GFDL，Hadley）气温及降水的模拟结果，对温室气体排放情景SRES-A2和B2影响下，青藏高原及铁路沿线未来50年气温和降水的变化进行了分析，包括整个青藏高原地区2011-2040年，2041-2070年的温度和降水空间分布特征以及21世纪前50年温度和降水变化的线性倾向等，结果表明：在人类活动引起的温室气体不断增加的情况下，21世纪青藏高原地区的温度将继续增加，在B2排放情景下，2011～2040年年平均温度增暖在高原主体达到1．6℃；20412070年，整个青藏高原的温度将上升2．8～3．0℃，A2排放情景下的升温幅度比B2排放情景下略高。对青藏铁路沿线地区各站A2和B2两种排放情景下，每10年平均的温度分析表明，在A2排放情景下，到2050年前后青藏铁路沿线各站的温度增加将是2010年时的2～3倍左右，A2时在2．56～2．96℃之间，B2时在2．37～2．65℃之间。对21世纪前50年整个青藏高原地区温度变化的线性倾向的空间分布的分析可知，在A2排放情景下，大部分都在1.5～2．5℃／50a，冬季大部分地区的变暖倾向都在2．0℃／50a以上，有些地区达到2．5℃／50a以上，夏季在2℃／50a左右；B2时青藏高原地区温度变化倾向的分布趋势与A2时基本一致，只是变化的数值偏低约0．5℃。对21世纪青藏高原地区降水变化的预估结果表明，与温度不同，在两种不同的排放情景下，降水的变化较为复杂。总体来说，21世纪前50年青藏高原大部分地区的降水为增加趋势。  相似文献   

A coupled simple climate model and its global analysis     

X. Fan  J.-F. Chou  B.-R. Guo  M. D. Shulski 《Theoretical and Applied Climatology》2004,79(1-2):31-43

Summary An atmosphere-land coupled simple climate model is constructed and its climatic properties are analyzed by introducing a global analysis method, cell mapping. The simple model is a nonlinear six order simplified climate model featured with chaotic dynamics, dissipation, and forcing source, which are the main features of the real climate system. The cell mapping method is applied with this coupled system. Numerical experiments are carried out for investigating the interactions between the fast-changing atmospheric variables and slow-changing underlying surface variables. The predictability of the system is also investigated via the global analysis, with which the evolution of the system is translated to the evolution of probability transition on a Markov Chain. An effective scheme is proposed for computing the probability transition matrix for the coupled system. Predictions can be made based on the combination of dynamics and statistics. The importance of constructing the coupled model is shown by globally analyzing the predictability of the coupled system. The coupling mechanism prolongs the memorization of initial information, and then the predictability as well.  相似文献   

青藏高原东北边缘冰雹形成机理   总被引：23，自引：7，他引：16  

康凤琴  张强  马胜萍  乔艳君  郭学良 《高原气象》2004,23(6):749-757

"穴道"理论认为,冰雹云中存在冰雹形成和增长的"穴道"。本文以在青藏高原东北边缘及毗邻地区常诱发冰雹灾害的东移短小切变线天气过程为研究背景,采用三维冰雹云分档模式,用MM5V3中尺度气象模式提供冰雹云模拟研究所需的环境大气状况,模拟研究了各类冰雹形成和增长的过程。结果表明,温度、云中上升气流、水平风速零线和云中各类水成物、各类冰雹质粒的空间分布满足"穴道"理论描述的配置区域是冰雹颗粒含水量的大值范围。同时显示出了小冰粒子(D<1mm)、霰和雹胚(1mm相似文献   

甘肃永登强对流云的雷达气候学特征分析   总被引：11，自引：5，他引：6  

渠永兴  张强  康凤琴 《高原气象》2004,23(6):773-780

利用甘肃永登19年(1971—1985年，1999—2003年)的雷达回波资料，分析了强对流云回波形成及分布特征与甘肃永登地区特殊地形的关系；强对流天气大尺度天气背景和相应的强对流雷达回波的移动、高度、强度和回波谱等特征。结果表明，该区的特殊地形造成气流阻挡并使其折转汇合、垂直运动剧烈加速，使得对流云迅速发展，这是该区对流云形成和分布的决定因素；高空天气形势和对流云结构制约了对流云雷达回波的移动和基本特征。雹云回波谱表明，雹暴对流活动一般均处于旺盛状态，强回波高度和其所处的云内温度是形成雹云的重要条件。  相似文献   

北极涛动与我国北方强沙尘暴的关系   总被引：3，自引：2，他引：1  

宋连春  俞亚勋  孙旭映  孙国武 《高原气象》2004,23(6):835-839

使用1954—2003年北极涛动指数、500hPa纬向环流指数和沙尘暴等气候观测资料，针对我国北方春季沙尘暴年际和年代际变化趋势，分析了以北极涛动为代表的大气环流异常变化的气候特征，揭示了其与我国春季沙尘暴相关的事实。结果表明：近50年北极涛动指数表现出由负位相向正位相转变的趋势，当冬季(12月～2月)北极涛动为负位相时，相应的纬向环流指数为负距平，中高纬度西风气流偏弱，有利于极地冷空气向南输送，西伯利亚高压偏强，我国北方春季易多发区域性沙尘暴；反之则不易发生区域性沙尘暴。  相似文献   

Humidity Effect and Its Influence on the Seasonal Distribution of Precipitation δ~(18)O in Monsoon Regions     

章新平  刘晶淼  何元庆  田立德  姚檀栋 《大气科学进展》2005,(2)

The humidity effect, namely the markedly positive correlation between the stable isotopic ratio in precipitation and the dew-point deficit ATd in the atmosphere, is put forward firstly and the relationships between the δ18O in precipitation and ATd are analyzed for the Urumqi and Kunming stations, which have completely different climatic characteristics. Although the seasonal variations in δ18O and △Td exhibit differences between the two stations, their humidity effect is notable. The correlation coefficient and its confidence level of the humidity effect are higher than those of the amount effect at Kunming, showing the marked influence of the humidity conditions in the atmosphere on stable isotopes in precipitation. Using a kinetic model for stable isotopic fractionation, and according to the seasonal distribution of mean monthly temperature at 500 hPa at Kunming, the variations of the δ18O in condensate in cloud are simulated. A very good agreement between the seasonal variations of the simulated  相似文献   

Uncertainty of the Numerical Solution of a Nonlinear System‘s Long-term Behavior and Global Convergence of the Numerical Pattern     

HU  Shujuan 《大气科学进展》2004,(5)

1. Introduction The partial di?erential equations for atmosphericmovement are often nonlinear and often very complex;we usually cannot obtain an analytic solution but must?nd a numerical solution. The general method is ?rstto discretize the space varia…  相似文献