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背风波形成的非线性数值试验及其对降水的影响 总被引：7，自引：0，他引：7
众所周知,降水现象是由大、中、小不同尺度的运动造成的。而中,小尺度的降水,往往起着非常重要的作用。引起局地暴雨和阵性降水(包括冰雹)的灾害性天气,都是在适当的大尺度背景下的中小尺度的天气现象。而这种中、小尺度天气现象,又往往与地形有关。例如,背风坡大风及冰雹问题在云贵高原横断山脉,有些地方背风坡的年降水量比迎风坡要多。而冰雹现象又往往多数产生在地形的背风面。在云南、甘肃、河南、河北等都发现有上述情况。要抓灾害性天气预报,要作好降水预报,只报出大尺度的天气形势和降水是远远不够的,还应该把中小尺度的降水预报作好才行。因此根据大形势数值预 相似文献
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1.引言在历史上气象学家们一直倾向于从空间和时间尺度有很大差别的两个观点出发来研究大气动力学。在试图解释最接近人们生活环境的地面上的细微运动特征方面,他们发展了微气象学,来处理空间尺度为几米和时间尺度大约一分钟的大气动力学问题。同样,为了预报大气中天气形势的发展,气象学家们对空间尺度为一千公里以上和时间尺度为一周的大尺度动力学的运动特征给以极大的关注。尽管“大尺度”气象学和“小尺度”气象学包含了许多大气过程,但仍然有大量重要的天气现象,它们的空间尺度和时间尺度居于这二者之间。我们对这些中间尺度的认识是逐渐的,这倒不是因为它们不重要,而是因为要获得那些与它们有关的观测资料是困难的。然而,近年来由于对城市环境和强风暴 相似文献
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应用单多普勒雷达资料反演风场作暴雨中尺度分析 总被引：7，自引：2，他引：7
针对2002年6月23日发生在安徽西部的一次暴雨过程，以有限的探空资料作为大尺度背景场，应用合肥CINRAD-98D多普勒雷达资料，通过准四维变分分析方法进行反演，获得了不易被常规探测到的中小尺度三维风场，由此分析了引起强降水的中尺度天气系统。指出暴雨中心位于风速切变的下方，同时上空也伴随辐合中心，以及正涡度极大值。分析结果表明，变分法是一种较为准确的从雷达资料中提取三维风场的方法。利用雷达资料反映中尺度天气系统，同时又加入大尺度的背景场作为基础，两者相互弥补，能较真实地反映实际天气状况。在气象预报中有效地应用多普勒雷达资料，有助于研究更为细致的中小尺度天气系统结构，而且也可为中小尺度数值预报模式提供准确的初始场。 相似文献
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多普勒天气雷达在阵风锋监测中的应用 总被引：6，自引：8，他引：6
本文利用多普勒天气雷达(CINRAD/SA)及常规资料,对2004年5月22日发生在江苏东北部的一次阵风锋天气现象进行了详细分析。阐述了阵风锋的反射率因子和多普勒径向速度特征,如回波强度、宽度、成因及冷锋过境前后的速度场特征等。并且探讨了阵风锋在短时预报中的应用。 相似文献
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通过对天气尺度的平均环而场、中尺度天气系统、大气稳定度、卫星云图等资料进行分析，从几个方面归纳出百色地区1996年3月27～28日和5月28日两次重大天气过程的一些特征，从中揭示了出现冰雹天气和暴雨天气的某些异同点：大尺度环流背景相似而中小尺度系统其强度和范围差异明显。为今后的重大天气预报提供一些新的特征指标。 相似文献
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相同大尺度环流背景下不同类型强对流天气个例分析 总被引：1，自引：0，他引：1
利用常规观测、雷达、卫星和自动站等资料,对2013年3月23日广西一次区域性强对流天气过程中两种不同类型强对流天气现象产生的局地环境条件、触发机制及中尺度等特征进行了对比分析。结果表明：在相同大尺度环流背景下,两种类型强对流天气（即干对流型和混合对流型）在大气层结、湿层厚度、对流有效位能（CAPE值）和垂直风切变等局地环境上存在一定差异;其触发机制不同,广西西部干对流由位于地面锋前暖区的辐合线触发,而北部混合型强对流则由地面锋面触发;雷达和卫星图像上,两类强对流在形态、强度和移速上均存在明显差异,这些差异对广西不同类型强对流天气的监测预警具有一定的参考价值。 相似文献
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暴雨是中尺度天气现象。要解决暴雨的预报问题,从根本上讲必须搞清楚中小尺度系统发生发展的机制及其预报问题。由于目前获取的分析资料时间间隔太长、空间的距离又很大,因此对认识以致预报直接造成暴雨的中尺度系统的活动规律带来许多困难,这是暴雨预报常常失败的重要原因之一。现实的问题是如何根据现有的条件充分挖掘各种气象资料(包括物理量场的资料)的潜力,结合现代化的监视系统来努力提高短期暴雨预报水平。各种尺度的天气系统是互相联系、互相制约的,尽管中小尺度天气系统发生发展的预报还非常困难,但寻找其赖以发生发展的适宜环境场(摇篮)——大尺度的环流特征仍不失为短期暴雨 相似文献
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Observed daily precipitation data from the National Meteorological Observatory in Hainan province and daily data from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis-2 dataset from 1981 to 2014 are used to analyze the relationship between Hainan extreme heavy rainfall processes in autumn (referred to as EHRPs) and 10–30 d low-frequency circulation. Based on the key low-frequency signals and the NCEP Climate Forecast System Version 2 (CFSv2) model forecasting products, a dynamical-statistical method is established for the extended-range forecast of EHRPs. The results suggest that EHRPs have a close relationship with the 10–30 d low-frequency oscillation of 850 hPa zonal wind over Hainan Island and to its north, and that they basically occur during the trough phase of the low-frequency oscillation of zonal wind. The latitudinal propagation of the low-frequency wave train in the middle-high latitudes and the meridional propagation of the low-frequency wave train along the coast of East Asia contribute to the ‘north high (cold), south low (warm)’ pattern near Hainan Island, which results in the zonal wind over Hainan Island and to its north reaching its trough, consequently leading to EHRPs. Considering the link between low-frequency circulation and EHRPs, a low-frequency wave train index (LWTI) is defined and adopted to forecast EHRPs by using NCEP CFSv2 forecasting products. EHRPs are predicted to occur during peak phases of LWTI with value larger than 1 for three or more consecutive forecast days. Hindcast experiments for EHRPs in 2015–2016 indicate that EHRPs can be predicted 8–24 d in advance, with an average period of validity of 16.7 d. 相似文献
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Based on the measurements obtained at 64 national meteorological stations in the Beijing–Tianjin–Hebei (BTH) region between 1970 and 2013, the potential evapotranspiration (ET0) in this region was estimated using the Penman–Monteith equation and its sensitivity to maximum temperature (Tmax), minimum temperature (Tmin), wind speed (Vw), net radiation (Rn) and water vapor pressure (Pwv) was analyzed, respectively. The results are shown as follows. (1) The climatic elements in the BTH region underwent significant changes in the study period. Vw and Rn decreased significantly, whereas Tmin, Tmax and Pwv increased considerably. (2) In the BTH region, ET0 also exhibited a significant decreasing trend, and the sensitivity of ET0 to the climatic elements exhibited seasonal characteristics. Of all the climatic elements, ET0 was most sensitive to Pwv in the fall and winter and Rn in the spring and summer. On the annual scale, ET0 was most sensitive to Pwv, followed by Rn, Vw, Tmax and Tmin. In addition, the sensitivity coefficient of ET0 with respect to Pwv had a negative value for all the areas, indicating that increases in Pwv can prevent ET0 from increasing. (3) The sensitivity of ET0 to Tmin and Tmax was significantly lower than its sensitivity to other climatic elements. However, increases in temperature can lead to changes in Pwv and Rn. The temperature should be considered the key intrinsic climatic element that has caused the "evaporation paradox" phenomenon in the BTH region. 相似文献
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Storms that occur at the Bay of Bengal (BoB) are of a bimodal pattern, which is different from that of the other sea areas. By using the NCEP, SST and JTWC data, the causes of the bimodal pattern storm activity of the BoB are diagnosed and analyzed in this paper. The result shows that the seasonal variation of general atmosphere circulation in East Asia has a regulating and controlling impact on the BoB storm activity, and the “bimodal period” of the storm activity corresponds exactly to the seasonal conversion period of atmospheric circulation. The minor wind speed of shear spring and autumn contributed to the storm, which was a crucial factor for the generation and occurrence of the “bimodal pattern” storm activity in the BoB. The analysis on sea surface temperature (SST) shows that the SSTs of all the year around in the BoB area meet the conditions required for the generation of tropical cyclones (TCs). However, the SSTs in the central area of the bay are higher than that of the surrounding areas in spring and autumn, which facilitates the occurrence of a “two-peak” storm activity pattern. The genesis potential index (GPI) quantifies and reflects the environmental conditions for the generation of the BoB storms. For GPI, the intense low-level vortex disturbance in the troposphere and high-humidity atmosphere are the sufficient conditions for storms, while large maximum wind velocity of the ground vortex radius and small vertical wind shear are the necessary conditions of storms. 相似文献
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The spatial and temporal variations of daily maximum temperature(Tmax), daily minimum temperature(Tmin), daily maximum precipitation(Pmax) and daily maximum wind speed(WSmax) were examined in China using Mann-Kendall test and linear regression method. The results indicated that for China as a whole, Tmax, Tmin and Pmax had significant increasing trends at rates of 0.15℃ per decade, 0.45℃ per decade and 0.58 mm per decade,respectively, while WSmax had decreased significantly at 1.18 m·s~(-1) per decade during 1959—2014. In all regions of China, Tmin increased and WSmax decreased significantly. Spatially, Tmax increased significantly at most of the stations in South China(SC), northwestern North China(NC), northeastern Northeast China(NEC), eastern Northwest China(NWC) and eastern Southwest China(SWC), and the increasing trends were significant in NC, SC, NWC and SWC on the regional average. Tmin increased significantly at most of the stations in China, with notable increase in NEC, northern and southeastern NC and northwestern and eastern NWC. Pmax showed no significant trend at most of the stations in China, and on the regional average it decreased significantly in NC but increased in SC, NWC and the mid-lower Yangtze River valley(YR). WSmax decreased significantly at the vast majority of stations in China, with remarkable decrease in northern NC, northern and central YR, central and southern SC and in parts of central NEC and western NWC. With global climate change and rapidly economic development, China has become more vulnerable to climatic extremes and meteorological disasters, so more strategies of mitigation and/or adaptation of climatic extremes,such as environmentally-friendly and low-cost energy production systems and the enhancement of engineering defense measures are necessary for government and social publics. 相似文献
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《大气和海洋科学快报》2013,(1):67
正AIMS AND SCOPE Atmospheric and Oceanic Science Letters (AOSL) publishes short research letters on all disciplines of the atmosphere sciences and physical oceanography. Contributions from all over the world are welcome.SUBMISSIONAll submitted 相似文献
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<正>With the support of specialized funds for national science institutions,the Guangzhou Institute of Tropical and Marine Meteorology,China Meteorological Administration set up in October 2008 an experiment base for marine meteorology and a number of observation systems for the coastal boundary layer,air-sea flux,marine environmental elements,and basic meteorological elements at Bohe town,Maoming city,Guangdong province,in the northern part of the South China Sea. 相似文献
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《大气和海洋科学快报》2014,7(6):F0003-F0003
AIMS AND SCOPE
Atmospheric and Oceanic Science Letters （AOSL） publishes short research letters on all disciplines of the atmosphere sciences and physical oceanography. Contributions from all over the world are welcome. 相似文献
Atmospheric and Oceanic Science Letters （AOSL） publishes short research letters on all disciplines of the atmosphere sciences and physical oceanography. Contributions from all over the world are welcome. 相似文献
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《大气和海洋科学快报》2014,(5):F0003-F0003
AIMS AND SCOPE Atmospheric and Oceanic Science Letters （AOSL） pub- lishes short research letters on all disciplines of the atmos- phere sciences and physical oceanography. Contributions from all over the world are welcome. 相似文献
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《大气和海洋科学快报》2012,(3):273
正AIMS AND SCOPE Atmospheric and Oceanic Science Letters (AOSL) publishes short research letters on all disciplines of the atmosphere sciences 相似文献