2011年12月3-7日山东省连续大雾分析          下载免费PDF全文

王西磊  孟宪贵  赵京峰 《气象与环境学报》2013,29(5):20-25

利用2011年12月1-7日的常规探测资料和NCEP再分析资料,采取诊断分析的方法,分析了山东省大范围连续性大雾产生的天气背景、温湿条件和大气层结等特征。结果表明：此次连续大雾发生在稳定的大气层结下,高空中纬度环流平直,地面气压场上表现为从东西伯利亚到华南一个庞大的变性高压区（山东处于高压的中部）,天气形势稳定;在高分辨率可见光云图上,大雾图像顶部较光滑、边缘较清晰,在红外云图上特征不明显;近地面层是弱的东到东北风（风力在2 m·s^-1以下）,既有利于海洋上暖湿气流的平流输送,也为较冷的下垫面的建立创造了条件;大气边界层湍流活跃,湍流动力垂直输送明显;大雾初期低空有明显的逆温层,天气状况较好,辐射降温明显,大雾性质以辐射雾为主,中后期是暖湿空气平流到温度较低的下垫面上时冷却而形成,以平流雾为主。  相似文献   

A QUANTITATIVE STUDY FOR ABNORMAL FREEZING RAINS AND SNOWSTORMS IN SOUTHERN CHINA IN EARLY 2008   总被引：2，自引：1，他引：1  

傅敏宁  邹海波  吴俊杰  吴珊珊  袁卓建  王四化 《热带气象学报(英文版)》2013,19(1):67-79

A quantitative diagnosis is carried out for the upward branch of a local meridional circulation over southern China(SC) during the abnormal snowstorms with severe freezing rain from 10 January to 3 February 2008.The diagnostic study shows that the upward branch is mainly associated with the zonal advection of westerly momentum and meridional temperature advection instead of the latent heating(which is commonly the dominant factor in many other storm cases).The corresponding weather analyses indicate that(1) the zonal advection of westerly momentum represents the effect of the upper-level divergence on the anticyclone-shear side in the entrance of a 200 hPa westerly jet with a westward deviation from its climatological location over southwestern Japan;(2) the meridional temperature advection represents the interaction between the mid-lower layer(850 to 400 hPa) warm advection over SC(ahead of temperature and pressure troughs with the latter trough deeper than the former in the Bay of Bengal) and cold advection over north China(steered by an underlying flow at 500 hPa);(3) the relatively weak vapor transport(compared to that of spring,summer and autumn) from the Bay of Bengal and the South China Sea to SC and the existence of a temperature inversion layer in the lower troposphere over SC diminish the effect of latent heating.With the significant increase of vapor transport after 24 January,the role of latent heating is upgraded to become the third positive contributor to the upward branch over SC.  相似文献   

一次降雪过程持续原因分析   总被引：4，自引：2，他引：2  

吴海英  王啸华  韩桂荣  尹东屏  王静苒 《气象科学》2013,33(3):308-315

利用多种观测资料和中尺度数值模拟资料,对2011年2月14日发生在江淮地区的一次预报失误的持续性降雪过程进行较为全面的分析.结果表明:前期的降水导致近地面维持较大湿度,补充南下的冷平流促使低层大气接近饱和,降雪持续期间,水汽集中在对流层低层浅薄的层次中;对流层中层发展和维持的强冷平流导致降水区上空迅速降温减湿,从而在对流层中低层,逐渐建立起弱对流不稳定层结.而叠置其上的稳定层则将对流活动和水汽的向上输送限制在对流层低层内,使得水汽和能量得以在一定范围内集中;不断补充南下的冷空气强迫近地层风场发生扰动,形成的中尺度切变线,为这种浅薄层次下的弱对流活动提供了触发条件.尽管辐合抬升较弱,但与其它季节相比,气温较低的冬季,在抬升凝结高度较低的大气中,水汽易凝结成云致降水.造成这次预报失误的原因,是忽略了近地层系统的变化.另外,对补充冷空气的影响作用考虑不充分.  相似文献   

一次罕见黄渤海大风天气成因分析     

朱男男  刘一玮  孙密娜 《气象科技》2017,45(6):1070-1076

利用气象常规资料、风廓线资料和NCEP/NCAR 1°×1°再分析资料,对2015年10月1日黄渤海罕见大风天气成因进行分析。结果表明:较强冷空气与快速发展的入海气旋相互作用形成强气压梯度是导致此次海上强风的主要原因。对流层中低层强冷平流区与地面变压风大值区有较好的对应关系。上下相接的整层冷平流有利于地面形成强气压梯度和变压梯度。气压梯度在大风形成的初期起主导作用,变压梯度有利于强风的维持。本次过程出现明显动量下传现象,大风形成初期,500~1000m出现低空动量下传并影响地面风场,高空槽过境后,2000m以上的高空动量能够影响地面风场。风廓线观测到低层强风并伴有强的下沉运动,可以作为海上大风临近预警的指标之一。  相似文献   

定量诊断2008年初南方罕见冰冻雨雪天气   总被引：2，自引：1，他引：2  

邹海波  刘熙明  吴俊杰  吴珊珊  袁卓建  王四化 《热带气象学报》2011,27(3):345-356

根据NCEP/NCAR逐日再分析资料和每三小时一次的TRMM 3B42降水资料,利用改进后的局地经向环流线性诊断模式(不用地转风近似而用旋转风估算水平环流经向分量),定量分析了2008年初我国南方地区局地经向环流的垂直分量(-ωMC)的演变情况.结果表明:当我国南方地区发生强降水时,局地经向环流的强上升支气流((-ωM...  相似文献   

GRAPES模式中高精度正定保形物质平流方案的研究Ⅰ:理论方案设计与理想试验     

沈学顺  王明欢  肖锋 《气象学报》2011,69(1):1-15

平流计算的精度对数值模式的结果有着重要影响.如何在半拉格朗日模式中发展高阶精度的标量平流计算方案是提高半拉格朗日数值模式精度的重要问题.文中采用计算流体力学中一个新的高精度正定保形的物质平流方案,通过映射单元格方法将其与半拉格朗日模式结合起来,既保留了半拉格朗日时间积分方案中积分时间步长大、计算效率高的特点,又发挥新方...  相似文献   

若尔盖高寒湿地夏季近地面水平热平流对地表能量闭合度的影响研究     

陆宣承  文军  杨越  田辉  刘闻慧  武月月  蒋雨芹 《高原气象》2022,(1):122-131

近地面能量不闭合问题一直以来都是陆面过程研究的一个重要的科学问题,且在非均匀湿地下垫面的近地面尤为突出.利用中国科学院若尔盖高原湿地生态系统研究站花湖观测场的地面风场和温度场数据,计算了由湿地下垫面热力非均匀性引起的水平热平流,并分析了考虑水平热平流后地表能量平衡的变化.结果表明:2017年夏季若尔盖湿地近地面水平热平...  相似文献   

夏季中国东部副高北缘雨带强度年际变化成因:副热带西风异常的动力强迫     

王士新  左洪超  王明星  朱岩  左斌 《冰川冻土》2016,38(5):1273-1280

根据中国东部副高北缘雨带的气候平均位置季节移动情况,定义了雨带强度指数,并用回归分析证实此指数能够很好地描述初夏和盛夏雨带的强度.基于定义的雨带强度指数分析发现,初夏副热带西风对雨带强度影响显著,但盛夏无显著影响.进一步研究表明,初夏副热带西风的增强通过作用于雨带上空西高东低的气温场使得对流层中层暖平流增强,进而加速上升运动,从而增强雨带;而到盛夏,环流形势的季节变化导致暖平流在雨带强度变化中起到的作用减小,这减弱了副热带西风对雨带强度的影响.  相似文献   

Sea surface height oscillation with quasi-four-month period along the continental slope in the northern South China Sea     

曹俊和  刘秦玉 《中国海洋湖沼学报》2012,30(2):352-359

The sea surface height oscillation with a quasi-four-month period (SSHO4) along continental slope in the northern South China Sea (NSCS) is detected using satellite altimeter data and an ocean model simulation. The SSHO4 is at southwest of Dongsha Island, and is characterized by a wavelength of ~600 km and a southwestward phase speed of ~0.1 m/s. Crossing the climatological background SST front, geostrophic currents corresponding to the SSHO4 generally induce sea surface temperature (SST) "tongues" during January-March. The cold and warm SST tongues appear southwest of cyclonic and anticyclonic eddies, respectively. The distance between the warm and cold SST tongues is about half the wavelength of the SSHO4. The geostrophic currents play an important role in lateral mixing, as manifested by the SST tongue phenomena in the NSCS.  相似文献   

Simulating the dispersal of tephra from the 1991 Pinatubo eruption: Implications for the formation of widespread ash layers     

Julie Fero  Steven N. Carey  John T. Merrill 《Journal of Volcanology and Geothermal Research》2009,186(1-2):120-132

PUFF and HAZMAP, two tephra dispersal models developed for volcanic hazard mitigation, are used to simulate the climatic 1991 eruption of Mt. Pinatubo. PUFF simulations indicate that the majority of ash was advected away from the source at the level of the tropopause (~ 17 km). Several eruptive pulses injected ash and SO₂ gas to higher altitudes (~ 25 km), but these pulses represent only a small fraction (~ 1%) of the total erupted material released during the simulation. Comparison with TOMS images of the SO₂ cloud after 71 and 93 h indicate that the SO₂ gas originated at an altitude of ~ 25 km near the source and descended to an altitude of ~ 22 km as the cloud moved across the Indian Ocean. HAZMAP simulations indicate that the Pinatubo tephra fall deposit in the South China Sea was formed by an eruption cloud with the majority of the ash concentrated at a height of 16–18 km. Results of this study demonstrate that the largest concentration of distal ash was transported at a level significantly below the maximum eruption column height (~ 40 km) and at a level below the calculated height of neutral buoyancy (~ 25 km). Simulations showed that distal ash transport was dominated by atmospheric circulation patterns near the regional tropopause. In contrast, the movement of the SO₂ cloud occurred at higher levels, along slightly different trajectories, and may have resulted from gas/particle segregations that took place during intrusion of the Pinatubo umbrella cloud as it moved away from source.  相似文献