Dynamical downscaling simulation and projection for mean and extreme temperature and precipitation over central Asia

Climate Dynamics - As a typical arid and semi-arid area, central Asia (CA) has scarce water resources and fragile ecosystems that are particularly sensitive and vulnerable to climate change. In...     

Improved methods for estimating equilibrium climate sensitivity from transient warming simulations

Climate Dynamics - Equilibrium climate sensitivity (ECS) refers to the total global warming caused by an instantaneous doubling of atmospheric CO2 from the pre-industrial level in a climate system....     

基于分段函数法计算湿球温度研究

核电厂冷却塔设计气象条件中,湿球温度是重要的设计气象参数之一。近年来,由于实行自动观测,相对湿度值由仪器自动测定,因此不少气象站已经停止了湿球温度的观测,这给电厂气象参数的分析计算造成了一定困难。为此,根据气压分布型特点和分段函数,提出利用干球温度和相对湿度来计算湿球温度的新方法,经河南省郑州、南阳和商丘3站的应用,效果良好。     

云南风能资源及其开发利用研究进展

介绍了云南风能资源及其开发利用的研究现状和研究成果。分析了云南风能资源评价历程、分布特点和风电开发建设情况。总结了云南有关风电场选址、风能资源评估、风电功率预测预报以及山区风电场和风电机组设计的研究成果。剖析了云南风能资源及其开发利用中存在的问题并提出今后的发展方向。     

一例苏皖中尺度对流复合体模拟结果的诊断分析

利用2010年7月22日苏皖中尺度对流复合体（MCC）数值模拟输出结果,考察了模式对MCC的模拟能力,并对模拟结果做了动力和热力诊断分析,以揭示盛夏江淮下游MCC的特征。结果表明：1） 三重嵌套网格距为3.3 km的区域WRF模式的模拟效果较佳,结果与实况一致,并可利用模拟降水的范围及强度来确定MCC的位置及演变。2） 此MCC维持约10 h,其南北不对称,并随西太平洋副热带高压西伸北抬而随之北抬。MCC核心区对流层低层有水汽丰沛的入流,并有强辐合区,呈对流不稳定层结;中层有深厚的强上升运动,并因凝结潜热大量释放呈中性层结;高层则有出流;MCC核心区对流降水非常强。3） 在垂直剖面上,该核心区散度存在中低层辐合、高层辐散的柱状结构,此配置有利于强对流维持和加强,中低层以上有深厚的强上升气流柱,这些都是MCC核心区存在强对流的标志。该MCC的螺旋结构表明其中的强对流高度有组织。     

2017年3月江苏北部一次雷雨大风天气过程分析

利用多种常规观测资料和NCEP／NCAR再分析资料,分析了2017年3月1日江苏北部出现的一次罕见冷空气雷雨大风天气过程的发生背景、地面要素和云团演变特征,同时从大气动力、热力和水汽条件出发分析了午后对流的成因。结果表明：此次过程发生前,江苏地区位于高空槽前,对流层中低层有冷式切变线伴随两股冷空气南下,受江苏省北部地面气旋阻挡,冷空气在上游堆积,当气旋东移入海冷空气爆发式南下时,造成严重的大风灾害。此次过程中,对流层中高层大气降温而低层回温使大气温度直减率增大,为对流发生提供不稳定条件,但水汽输送主要集中在低层,且高层大气无明显抽吸作用,导致此次过程未发生强对流性降水,主要以大风灾害性天气为主。     

A Case Study of the November 2012 Mixed Rain-Snow Storm over North China

A mixed rain-snow storm associated with a strong burst of cold air and development of an extratropical cyclone occurred over North China from 3 to 5 November 2012.This early snowfall event was characterized by a dramatic drop in temperature,strong winds,high precipitation intensity,broad spatial extent,and coexistence of multi-phase precipitating hydrometeors.This study investigates the multi-scale interactions between the large-scale circulation background and the synoptic-scale weather systems associated with the storm.The results are as follows.（1） The Arctic Oscillation （AO） had been in its negative phase long before the event,leading to southward advection of cold air into North China in advance of the storm.（2）The large-scale atmospheric circulation experienced a decreased number of long waves upstream of North China prior to the storm,resulting in reduced wave velocity and an almost stagnant low pressure system （extratropical cyclone） over North China.（3） An Ω-shaped blocking high over East Asia and the western Pacific obstructed the eastward movement of an upstream trough,allowing the corresponding surface cyclone to stabilize and persist over Beijing and its neighboring areas.This blocking high was a major factor in making this event a historically most severe precipitation event in autumn in Beijing for the past 60 years.（4） Baroclinic instability at lower levels gave rise to rapid development of the cyclone under the classical ＂second type＂ development mechanism for extratropical cyclones.（5） Moisture originated from the Yellow Sea entered the slowly-moving cyclone in a steady stream,creating fairly favorable water vapor supply for the heavy rainfall-snowfall,especially during the later stage of the cyclone development.（6） Moisture transport and frontal lifting triggered low-level instability and updrafts.Intensification of the front enhanced the vertical wind shear,causing conditional symmetric instability （CSI） to expand upward within the unstable lower troposphere,and to eventually gear into the CSI region of the upper troposphere,which facilitated the upward development of low-level updrafts.