广东沿海强东北季风的气候统计特征

通过对1988－1997年冷空气造成的广东沿海强东北季风过程的气候统计分析，发现广东的强东北季风有明显的月分布规律，而年际变化有逐渐减少的趋势；强东北季风与地面因子相关程度较高，而与850hPa要素相关性较低；同时发现地面冷高压中心位置聚合度较高，但不同月份、不同时次，其中心位置有明显差异。     

东亚冷涌期间低纬环流和降水形成的数值试验

应用数值试验的方法，研究了东亚冷涌期间低纬环流和降水的形成。结果表明：低纬积云对流作用加强了东北季风和东北信风，但阻滞了热带辐合带进一步南移。印尼和澳大利亚北部季风降水可以独立存在。南海冷涌以及越赤道的西太平洋东北信风都可以是澳大利亚北部夏季风及降水形成的重要因子。数值研究还指出；印尼加里曼丹的强季风降水及常驻性低层扰动形成的基本因子是南海冷涌所触发的积云对流发展。印尼、加里曼丹地形及东北信风扰动可影响该处降水的强度。     

区间概率函数在晋城市降水概率预报中的应用研究

本文主要应用区间概率函数转换预报因子，经过相关比筛选。进行因子回归，构建分量级降水概率预报方程，同时应用T213L31数值预报产品统计释用方法，结合最优子集回归构造分时刻预报方程，最后进行概率预报。我们根据晋城气候区划，设计平川和山区两种降水概率预报方程。为晋城市开展降水概率预报提供了基础。     

超百年一遇洪水暴雨分析预报

本文对１９９３年８月３～５日洪水暴雨过程，作了天气学分析。指出是在纬向环流型下，西南季不入侵，暖（横）切变线低涡影响致洪暴雨类型。来自低纬度的偏南低空急流，是季风气团、西南季风的标志，也是一支暖湿输送带，前部有强辐合上升运动，弄造成湿对流不稳定。大暴雨落区在副热带急流锋区右侧，综合高低空急流之间天气学和数值产品诸因子，给出大暴雨中短期预报模型     

开封春季24h大风预报方法

利用开封1981-2000年3—5月的大风资料，依据冷空气路径，将大风分为东北型、西北型；选出预报因子，用逐步回归方法，对因子进行筛选，选出效果较好的预报因子建立方程。     

东北冷涡暴雨的短期预报系统

东北冷涡暴雨是指在东北冷涡天气形势下，东北地区出现3个或以上气象站日雨量大于等于50mm的暴雨。根据东北冷涡暴雨的成因分析结果，应用1993～1995年6～8月日本数值预报传真图资料，针对东北冷涡暴雨形成的有利天气形势和热力、动力特征，对数值预报产品进行天气动力解释，选择数值预报因子，确定因子的可信度，采用MYCIN不精确推理方法，建立了东北冷涡暴雨预报系统。     

MOS分级降水概率预报的试验

一、基本思路和方法 (一)分级降水概率预报 美国和日本开展概率预报已将近十年,服务效果较好。因此,目前开展概率预报的试验是必要的、可行的,其主要原因如下: 1.概率预报符合天气预报的特点。一方面,由于影响天气演变的因子很复杂,数值预报方程不能包含所有影响因子,或者不     

夏季省级分区降水概率预报自动化系统

利用多年气象观测资料，数值预报产品，各种天气系统及相互配置与多年降水资料进行了相关统计，精选了与降水密切相关的因子，利用多因子条件下的概率组合方法，建立了夏季省级分区降水概率预报经系统。在实际预报业务中取得了较好的预报效果。     

南海西南季风强度与茂名降水的关系

利用NECP/NCAR再分析资料和茂名地区观测站1974—2013年降水资料,运用相关分析等统计方法,探讨近40年来西南季风强弱与茂名降水的关系。结果表明:南海西南季风强度对茂名汛期、年降水量的影响有非对称性,南海西南季风强,茂名汛期、年降水较常年偏多;西南季风弱,茂名降水不确定,各月规律不同。西南季风强度与茂名某些月份尺度的相关性比季、年尺度的相关性较好,特别是冬季月份。近40年茂名暴雨日分布表现为单峰型,暴雨集中在5—9月,7月为峰值;各季风年极端降水多发的月份不同,强季风年为4—9月、正常年为5—8月、弱季风年为5—9月。强季风年极端降水发生的概率大于其它年份,正常年极端降水发生的概率较小。     

数值预报产品结合天气概念模式做南海风力中期预报

冬半年东北季风潮的暴发常使南海海区产生6级以上大风天气。过去主要依靠常规天气图提供的信息,先做出对流层500hPa形势预报,据此估计出地面气压场,然后做出大风过程的预报。3—5天高空形势预报主要依据长波调整理论和外推,再加经验。近年来,数值预报的中期形势预报能力有很大提高,特别是欧洲中期天气预报中心(ECMWF)     

广东沿海强东北季风的概率预报方法

用1979～1999年共21年资料分析了全球越赤道气流的空间分布,并初步讨论了东半球低层主要通道越赤道气流强度的年际变化特征。结果表明,全球越赤道气流分布存在明显的空间不对称性,即通道分布的高低层不对称性和沿纬圈不对称。低层通道窄而多,高层通道宽而少;东半球低层通道数目远较西半球多,且强度更强。无论高、低层,夏季越赤道气流总和都强于冬季。这也反映了南北半球空气质量交换的时空分布的不对称性,即空气质量的交换主要集中在夏季和东半球。 东半球低层越赤道气流的年际变化主要受TBO(2～3年周期)和ENSO(4～7年周期)的周期振荡影响,尤其是北半球夏季85 oE弱的越赤道气流年份基本上都与ENSO年相对应。这说明85 oE越赤道气流的强弱不仅决定于南北半球环流,还与热带纬向环流有关。而冬季105 oE越赤道气流的强弱不仅受TBO的影响,同时还受ENSO的影响。东半球各不同通道越赤道气流的年际变化特征必将对亚洲季风及降水有重要影响。     

东北夏季降水异常的年代际、年际构成及成因分析

利用NCEE／NCAR再分析月平均海平面气压资料、中国160站月降水资料、英国气象局和英国大气资料中心月平均海表温度资料，使用周期分析、奇异值分解和旋转EOF分析方法，分析了东北夏季降水异常的年代际、年际构成及成因。结果表明：(1)东北夏季降水异常构成中年代际、年际变化相对均衡，在局地年际变率中，东、南部年代际变化略强于西、北部。(2)在年代际、年际尺度上，东亚夏季风增强(减弱)，则东北降水偏多(偏少)。(3)E1 Nino事件与东北区夏季风异常无直接联系．故与东北夏季降水关系不密切。     

Idealized Numerical Simulations of Tropical Cyclone Formation Associated with Monsoon Gyres简

Monsoon gyres have been identified as one of the important large-scale circulation patterns associated with tropical cyclone （TC） formation in the western North Pacific.A recent observational analysis indicated that most TCs form near the center of monsoon gyres or at the northeast end of the enhanced low-level southwesterly flows on the southeast-east periphery of monsoon gyres.In the present reported study,idealized numerical experiments were conducted to examine the tropical cyclogenesis associated with Rossby wave energy dispersion with an initial idealized monsoon gyre.The numerical simulations showed that the development of the low-level enhanced southwesterly flows on the southeasteast periphery of monsoon gyres can be induced by Rossby wave energy dispersion.Mesoscale convective systems emerged from the northeast end of the enhanced southwesterly flows with mid-level maximum relative vorticity.The simulated TC formed in the northeast of the monsoon gyre and moved westward towards the center of the monsoon gyre.The numerical experiment with a relatively smaller sized initial monsoon gyre showed the TC forming near the center of the initial monsoon gyre.The results of the present study suggest that Rossby wave energy dispersion can play an important role in TC formation in the presence of monsoon gyres.     

A NUMERICAL EXPERIMENT STUDY ON THE FORMING MECHANISMS OF LOW-LATITUDE CIRCULATION CELLS AND PRECIPITATION DURING AN EAST ASIAN COLD SURGE

The forming mechanisms of low-latitude circulation cells and precipitation during an East Asian cold surge have been studied by using a five-layer primitive equation model.Numerical experiments show that in mid-high latitudes,the propagation of the East Asian winter monsoon is nearly a dry process;in low-latitudes,the effects of cumulus convection intensify the northeast monsoon and northeast trade wind;however,they also prevent the intertropical convergence zone(ITCZ) from further southward invasion,and strengthen the meridional and zonal cells over East Asia. Numerical results also indicate that the winter monsoon precipitation in Indonesia and Northern Australia can exist independently.Both the South China Sea(SCS) cold surge and the West Pacific northeast cross-equatorial trade wind are of importance for the formation of the Northern Australia summer monsoon and its precipitation.Numerical results show that the development of cumulus convection,triggered by the SCS cold surge,is a crucial factor in forming the heavy monsoon precipitation and low-level stationary disturbances in Indonesia and Borneo.The tropical topography and northeast trade wind disturbances only affect the intensity of precipitation there.     

Long-Term Variability of the Wind Field over the Indian Ocean Based on ERA-Interim Reanalysis

A detailed study of long-term variability of winds using 30 years of data from the European Centre for Medium-range Weather Forecasts global reanalysis (ERA-Interim) over the Indian Ocean has been carried out by partitioning the Indian Ocean into six zones based on local wind extrema. The trend of mean annual wind speed averaged over each zone shows a significant increase in the equatorial region, the Southern Ocean, and the southern part of the trade winds. This indicates that the Southern Ocean winds and the southeast trade winds are becoming stronger. However, the trend for the Bay of Bengal is negative, which might be caused by a weakening of the monsoon winds and northeast trade winds. Maximum interannual variability occurs in the Arabian Sea due to monsoon activity; a minimum is observed in the subtropical region because of the divergence of winds. Wind speed variations in all zones are weakly correlated with the Dipole Mode Index (DMI). However, the equatorial Indian Ocean, the southern part of the trade winds, and subtropical zones show a relatively strong positive correlation with the Southern Oscillation Index (SOI), indicating that the SOI has a zonal influence on wind speed in the Indian Ocean. Monsoon winds have a decreasing trend in the northern Indian Ocean, indicating monsoon weakening, and an increasing trend in the equatorial region because of enhancement of the westerlies. The negative trend observed during the non-monsoon period could be a result of weakening of the northeast trade winds over the past few decades. The mean flux of kinetic energy of wind (FKEW) reaches a minimum of about 100?W?m^?2 in the equatorial region and a maximum of about 1500?W?m^?2 in the Southern Ocean. The seasonal variability of FKEW is large, about 1600?W?m^?2, along the coast of Somalia in the northern Indian Ocean. The maximum monthly variability of the FKEW field averaged over each zone occurs during boreal summer. During the onset and withdrawal of monsoon, FKEW is as low as 50?W?m^?2. The Southern Ocean has a large variation of about 1280?W?m^?2 because of strong westerlies throughout the year.     

Temporal variability in the withdrawal phase of southwest monsoon over India and related consequences in northeast monsoon: a climatological perspective

Theoretical and Applied Climatology - The variability in duration of withdrawal phase of southwest monsoon over India is often witnessed to influence the northeast monsoon rainfall of India as...     

东亚季风区的季风类型

从地面流场正、斜压分量的冬夏季节转换的特征 ,对东亚至西太平洋季风区季风的性质进行了分析研究。结果表明 :这一地区的季风可分为 3种类型 :南海、华南沿海和低纬西太平洋主要为斜压流型季风区 ;华北北部、东北地区沿海主要为正压流型季风区 ;我国东部沿海和长江流域以及 2 7°N附近的西太平洋地区为正斜压流型共同形成的混合型季风区。     

南沙永暑礁近海面风的特征分析

选用南沙永暑礁1989年1月到2009年12月的水文气象月报表资料,运用概率统计的方法将风向和风速记录资料进行分析,定义了永暑礁的4个风期,通过风向风速的年内变化分析得出永暑礁盛行风风向在年内变化成顺时针向右偏移;无论是东北季风期,还是西南季风期,盛行风平均风速都大于非盛行风。东北季风期主导风向顺时针偏移时风力减小,西南季风期主导风向顺时针偏移时,到南南西风时最大,在西南风时略有减弱,呈现波状发展趋势。通过引入风速不稳定指数概念,发现永暑礁西南季风期风速变化突然,更不稳定。     

Definition and Features of the North Edge of the East Asian Summer Monsoon

By using daily total precipitable water(TPW) amount from the ECMWF reanalysis(ERA-44a) data in 1958-2001,the north edge of the Asian sub-tropical summer monsoon is defined by a normalized precipitable water index(NPWI),and its climatology and interannual/interdecadal variability are examined.The results show that two monsoon systems(the Indian and East Asian monsoon systems) can be identified in terms of monsoon edge defined by the NPWI over Asia.The mean north edge goes in the west-east direction along ...