中国近海蒸发波导的数值模拟与预报研究     

陈莉  高山红  康士峰  吴增茂 《中国海洋大学学报(自然科学版)》2011,(Z1):1-8

利用中尺度大气模式MM5对2007年中国近海大气蒸发波导进行了全年的高分辨的数值模拟。模拟结果统计表明,整个海域蒸发波导的平均出现概率约为90%。本文重点关注强度较大的蒸发波导,详细分析了其季节分布特征及其与海洋环流和海面气象条件的相关关系。研究发现,25°N以南的开阔海域的蒸发波导出现概率全年都较高,而以北的东海西北部、黄海与渤海,蒸发波导的出现概率呈现明显的季节特征;蒸发波导的空间分布受中国近海海洋环流的强烈影响,存在1个与黑潮区域相一致的带状波导高出现概率区域,台湾暖流、黄海暖流和对马暖流使得在某些季节相应海域蒸发波导出现概率高于其周围海域。此外,本文还基于WRF模式及其3DVAR系统构建了大气波导数值预报系统,尝试对中国东南海域的蒸发波导进行数值预报。  相似文献   

地形和水汽对“7.13”陕西暴雨影响的数值试验     

袁有林  左洪超  董龙翔  朱岩  王士新  袁媛 《干旱气象》2015,33(2)

应用WRF V3.5中尺度模式,对陕西省2013年7月12~13日的一次暴雨过程进行数值模拟,并设计了降低地形和减少水汽含量2个敏感性试验,探讨了地形和水汽对本次暴雨过程的影响。结果表明:(1)模式能较好地模拟出本次暴雨天气过程,反映出了主要雨带的形状,但模拟的降水量存在偏差,其可能原因是初始场不能合理反映大气实况;(2)嵌套区域d02的地形高度降低至原始高度的1/3后,107°E~109°E范围的散度垂直剖面呈辐合—辐散的双重结构,暴雨区上空中低层假相当位温梯度变大,垂直上升运动增强,进而改变了降水的强度和范围;(3)将初始场中暴雨区南面的水汽含量减少20%后,水汽通量散度极值中心值减少1/3,进而导致模拟区域的雨量减少了58%,表明偏南水汽的输送对本次暴雨雨量有显著增幅作用,暴雨过程中水汽聚集程度是判断暴雨过程雨量大小的关键因素之一。  相似文献   

WRF-Hybrid背景误差协方差调整在台风同化及预报中的应用研究   总被引：3，自引：1，他引：2  

沈菲菲  闵锦忠  许冬梅  王世璋 《气象科学》2015,35(2):150-159

利用雷达径向风单点试验和2006年8月超强台风"桑美"个例,首先研究了静态背景误差协方差的尺度化因子和方差在台风系统雷达资料同化中对台风路径和强度预报的影响。结果表明:在高时空分辨率的雷达资料同化中,较小的尺度化因子能显著改进对台风路径的预报;尺度化因子的影响比方差的影响更为显著。基于上述实验结果,进一步研究了WRFDA-Hybrid系统中"流依赖"控制变量的水平局地化和垂直局地化对台风预报的影响。试验结果表明:当"流依赖"的水平局地化距离与静态背景误差协方差的尺度化因子具有等效影响范围的时候,WRFDA-Hybrid能够得到比较合理的分析结果。同时针对雷达观测资料的空间分布特征,本文提出了一种新的基于雷达探测高度的垂直局地化方案,对台风的强度和路径预报均有显著的改进。  相似文献   

基于WRF/CALMET的近地面精细化风场的动力模拟试验研究   总被引：2，自引：1，他引：1  

张弛  王东海  巩远发 《气象》2015,41(1):34-44

本文利用中尺度动力模式 WRF和诊断模式CALMET对琼州海峡的两次冷空气过程的近地层风场进行模拟和诊断,所用的资料是美国NCEP再分析FNL资料。WRF模式第一至第四层网格的水平距离分别是27、9、3和1 km,并用WRF-1 km场以单向嵌套模拟方式降至200 m,同时以 WRF-1 km 预报场作为 CALMET 初猜场降尺度诊断至200 m。分别用CALMET-200 m风场、WRF-1 km风场和 WRF-200 m风场,3个风场的风速、风向与沿琼海海峡分布的21个测站（其中6个测风塔）观测资料进行检验比较分析。主要结论是：（1）CALMET-200 m的风速RMSE明显小于另外两组试验,风向RMSE总体上差异不大;在60～80 m高度上也没有明显差异。（2）在0～8 m·s－1风速,10 m高度上CALMET-200 m风场诊断结果最好,风速平均偏差值从4～0 m·s－1,WRF的两组试验平均偏差值比CALMET-200 m结果大约2 m·s－1,风向上表现为偏差的分布更加集中;60～80 m高度上,CALMET-200 m 诊断效果与 WRF-1 km 模拟效果相当,但是冷空气时段内 WRF-200 m的风速要远远差于另外两组试验;而3组试验的风向并无大的差异。（3）WRF／CALMET模式系统在非冷空气活动时段内的风速风向模拟诊断偏差更小,说明其在层结相对较稳定时模拟诊断的准确度更高。  相似文献   

Comparing future patterns of energy system change in 2 °C scenarios with historically observed rates of change     

《Global Environmental Change》2015

This paper systematically compares modeled rates of change provided by global integrated assessment models aiming for the 2 °C objective to historically observed rates of change. Such a comparison can provide insights into the difficulty of achieving such stringent climate stabilization scenarios. The analysis focuses specifically on the rates of change for technology expansion and diffusion, emissions and energy supply investments. The associated indicators vary in terms of system focus (technology-specific or energy system wide), temporal scale (timescale or lifetime), spatial scale (regional or global) and normalization (accounting for entire system growth or not). Although none of the indicators provide conclusive insights as to the achievability of scenarios, this study finds that indicators that look into absolute change remain within the range of historical growth frontiers for the next decade, but increase to unprecedented levels before mid-century. Indicators that take into account or normalize for overall system growth find future change to be broadly within historical ranges. This is particularly the case for monetary-based normalization metrics like GDP compared to energy-based normalization metrics like primary energy. By applying a diverse set of indicators alternative, complementary insights into how scenarios compare with historical observations are acquired but they do not provide further insights on the possibility of achieving rates of change that are beyond current day practice.  相似文献   

3D modeling of light interception in heterogeneous forest canopies using ground-based LiDAR data     

Dimitry Van der Zande  Jan Stuckens  Willem W. Verstraeten  Simone Mereu  Bart Muys  Pol Coppin 《International Journal of Applied Earth Observation and Geoinformation》2011

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Impacts of Cumulus Convective Parameterization Schemes on Summer Monsoon Precipitation Simulation over China   总被引：3，自引：0，他引：3       下载免费PDF全文

YU Entao  WANG Huijun  GAO Yongqi  SUN Jianqi 《Acta Meteorologica Sinica》2011,25(5):581-592

By using the Betts-Miller-Janjic, Grell-Devenyi, and Kain-Fritsch cumulus convective parameterization schemes in theWeather Research and Forecasting (WRF) model, long time simulations from 2000 to 2009 are conducted to investigate the impacts of different cumulus convective parameterization schemes on summer monsoon precipitation simulation over China. The results show that all the schemes have the capability to reasonably reproduce the spatial and temporal distributions of summer monsoon precipitation and the corresponding background circulation. The observed north-south shift of monsoon rain belt is also well simulated by the three schemes. Detailed comparison indicates that the Grell-Devenyi scheme gives a better performance than the others. Deficiency in simulated water vapor transport is one possible reason for the precipitation simulation bias.  相似文献   

新疆“2.28” 大风的中尺度数值模拟     

汤浩  李如琦  贾丽红 《气象》2011,37(11):1365-1371

受西西伯利亚较强冷空气入侵的影响,2007年2月28日02时,乌鲁木齐开往阿克苏的5807次旅客列车,在新疆三十里风区遭遇狂风,造成11节车厢脱轨侧翻。使用WRF模式对这次大风天气过程进行了数值模拟。结果表明：WRF模式较好地模拟了三十里风区大风的演变和分布特征,对逐时风速的模拟较实况偏小,但变化比较同步;很大的气压梯度和特殊的地形是大风形成的主要原因,狭管效应和下坡风同时存在。  相似文献   

WRF模式三维变分中背景误差协方差估计   总被引：2，自引：1，他引：1       下载免费PDF全文

王曼  李华宏  段旭  刘建宇  符睿  陈新梅 《应用气象学报》2011,22(4):482-492

利用WRF模式2008年5-10月逐日预报结果,通过NMC方法进行背景误差协方差(B)估计.给出其结构特征,进行单点数值试验,并利用不同B进行1个月的数值模拟试验,检验模拟降水效果.结果表明:通过单点数值试验验证估算的B结构合理.不同的B,资料同化过程差别较大,应用重新统计的B,同化效率更高,目标函数收敛更稳定.模式模...  相似文献   

Asymmetric rainband breaking in Typhoon Haitang (2005) before and after its landfall   总被引：1，自引：1，他引：0  

丁治英  王勇  沈新勇  徐海明 《热带气象学报(英文版)》2011,17(3):276-284

Using the WRF (Weather Research Forecast) model, this work performed analysis and simulation on the rainband change during the landfall of Typhoon Haitang (2005) and found that breaking may occur over land and oceans leads to distinct asymmetric precipitation. The breaking is related to the topographic effect as well as interactions between the typhoon and midlatitude systems at upper levels. During the landfall, divergent flows at the 200-hPa level of the South-Asian high combined with divergent flows at the periphery of the typhoon to form a weak, inverted trough in the northwest part of the storm, with the mid- and low-level divergence fields on the west and northwest side of the typhoon center maintaining steadily. It intensifies the upper-level cyclonic flows, in association with positive vorticity rotating counterclockwise together with air currents that travel stepwise into a vorticity zone in the vicinity of the typhoon core, thereby forming a vorticity transfer belt in 22–25? N that extends to the eastern part of the storm. It is right here that the high-level vorticity band is subsiding so that rainfall is prevented from developing, resulting in the rainbelt breaking, which is the principal cause of asymmetric precipitation occurrence. Migrating into its outer region, the banded vorticity of Haitang at high levels causes further amplification of the cyclonic circulation in the western part and transfer of positive vorticity into the typhoon such that the rainband breaking is more distinct.  相似文献