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1.
夏季沿亚洲副热带西风急流Rossby波传播及其与我国降水异常的联系 总被引：1，自引：0，他引：1
利用1960—2015年夏季(6—8月)NCEP 2.5°×2.5°全球逐日再分析资料,采用涡度源方程和Eliassen-Palm通量,对夏季沿亚洲副热带西风急流Rossby波活动的波源、能量传播及其与我国降水异常的关系进行了分析和研究。结果表明:夏季200 hPa大气准静止行星波产生的源地主要集中在地中海地区,亚洲副热带西风急流(ASWJ)中的准静止Rossby波在此激发并沿急流向东传播,东传过程中在急流轴南侧波流相互作用相对活跃。波作用通量的辐合辐散中心沿副热带西风急流交替分布,波流相互作用是ASWJ上西风强弱交替变化的动力机制。沿ASWJ交替分布的五个波作用通量辐合辐散关键区散度具有较强的关联性,表现为同一Rossby波列的不同部分,其中波源处Rossby波动能量的传播对其下游ASWJ的强弱影响最大,而急流关键区内纬向风的大小也与波作用通量散度场的强弱和分布密切相关。波源处以及位于我国青藏高原东部至黄土高原上空的波作用通量散度指数WFD-Ⅰ和WFC-Ⅱ与我国南、北方降水相关性较为显著,在WFD-Ⅰ为正异常年时,对应南方关键区降水偏多年份占比为62.5%,在WFD-Ⅰ为负异常年时,对应北方关键区降水偏多年份占比为80%;在WFC-Ⅱ为正异常年时,对应南方关键区降水偏少年份占比为66.7%,在WFC-Ⅱ为负异常年时,对应北方关键区降水偏少年份占比为81.8%。研究夏季波源处WFD-Ⅰ异常年导致我国降水异常的环流成因发现,WFD-Ⅰ为正异常年时,由上游波源地区激发的Rossby波向下游地区的能量频散偏强,位置偏南,波流相互作用导致我国南方上空高空急流加强,高低空辐散辐合配置加强,垂直上升运动增强,易造成我国南方地区降水异常偏多。WFD-Ⅰ为负异常年时,Rossby波能量的经向传播较强而纬向传播较弱,北方降水关键区受波通量辐散控制,高空西风急流加强,高低空辐散辐合配置和垂直上升运动增强,有利于我国北方地区降水的发展。 相似文献
2.
北大西洋涛动对新疆夏季降水异常的影响 总被引：19，自引：3，他引：16
利用1961~2003年NCEP/NCAR再分析和新疆75个气象站月降水资料,分析新疆夏季降水与沿西亚副热带西风急流Rossby波和北大西洋涛动（NAO）的关系,研究表明,夏季斯堪的纳维亚半岛-中欧—西亚和中亚的准静止波传播是联系NAO与沿西亚副热带西风急流波活动和新疆夏季降水变化的纽带。通过波作用量的动力学诊断分析,讨论了夏季NAO正、负位相异常年准静止波传播特征和差异,夏季NAO强弱活动影响斯堪的纳维亚半岛EP通量散度强度和位置异常,该区EP通量散度强度和位置异常导致强辐散中心在中高纬向东传播的准静止波和沿副热带西风急流准静止波活动变化,从而影响新疆夏季降水。 相似文献
3.
夏季亚洲副热带西风急流气候特征 总被引：8，自引：2，他引：6
利用1958～2003年NCEP/NCAR月平均再分析资料以及中国160站月降水资料,较全面、细致地分析了夏季亚洲西风急流气候特征.结果表明,亚洲急流存在其南北位置、强度和沿急流Rossby波活动的变化,定义的西风急流扰动指数能较好地综合反映急流的这3种变化.沿西亚急流和东亚急流的Rossby波活动具有不同的年际和年代际变化,并受不同波列活动的影响.西亚急流Rossby波活动(WAJRA)受北大西洋涛动影响,而东亚急流Rossby波活动(EAJRA)与南极涛动有联系.西亚急流Rossby波活动影响新疆夏季降水,东亚急流Rossby波活动影响100°E以东地区降水. 相似文献
4.
2020年1月24—25日广西出现一次罕见区域性强对流,过程伴随近20年最大范围冰雹天气。南支槽异常发展东移是此次过程的扰动背景,提供了必要的热动力及水汽条件。基于波作用通量及多尺度能量诊断方法,利用常规观测资料、风云卫星资料、NCEP/NCAR以及ERA5再分析资料,从能量转化角度对此次引发区域强对流的南支槽过程进行研究。结果表明:整个过程中纬度和副热带西风急流均较历史同期偏强,有利于上游扰动向下游传播。欧亚大陆上空存在南北两支活跃Rossby波列。源自地中海一带的南支副热带西风急流Rossby波列对南支槽起到主要调控作用,Rossby波能量沿急流频散并在南支槽区辐合,促进了南支槽发展东移。源自北大西洋阻塞高压内部的北支Rossby波列则起到协同作用,促进了乌拉尔山冷槽发展及其与中东槽合并,从而增强了南支波列向下游的传播,进一步增强南支槽;天气尺度有效位能向天气尺度动能的转换以及由背景场向天气尺度的动能输送是南支槽天气尺度扰动发展的主要贡献项。动能的平流输送将获得的天气尺度动能在空间上再分配,维持南支槽稳定发展东移。在此背景下,天气尺度向对流尺度的降尺度动能串级是区域强对流最主要能量... 相似文献
5.
夏季东亚高空副热带西风急流季节内异常的环流特征及前兆信号 总被引：2，自引：1，他引：1
位于东亚中纬度上空的东亚高空副热带西风急流是东亚季风环流系统中的重要成员,我国夏季降水雨带的季节内变化受东亚高空副热带西风急流位置季节内异常变化影响。根据1979~2008年中国降水资料、NCEP/NCAR再分析资料以及NOAA ERSST V3月平均海表温度资料,利用统计分析和物理量诊断方法对夏季东亚高空副热带西风急流位置季节内异常的东亚大气环流特征及外强迫信号的物理过程进行了探讨。研究指出:6月东亚高空副热带西风急流位置异常主要受欧亚大陆中高纬东传的Rossby波列位相变化影响,春季北大西洋海温异常是欧亚大陆中高纬度Rossby波列位相变化的最显著的外强迫信号;7月东亚高空副热带西风急流位置异常主要受西太平洋热带向副热带传播的Rossby波列位相变化影响,春季西太平洋热带海温异常是西太平洋热带向副热带传播的Rossby波列位相变化的最显著的外强迫信号;8月东亚高空副热带西风急流位置异常主要受南亚大陆向东亚大陆热带、副热带传播的Rossby波列位相变化影响,春季印度洋海温异常是南亚大陆向东亚大陆热带、副热带传播的Rossby波列位相变化的最显著的外强迫信号。 相似文献
6.
本文利用中尺度数值模式的高分辨率模拟结果,研究了夏季东亚副热带西风急流一次短时间尺度强度变化过程中的中尺度西风扰动特征和相应的动量输送特征。结果表明,此次急流强度短时间尺度变化以急流轴线为界,北侧增强,南侧减弱。急流整体增强和急流内部中尺度西风扰动的积累效应有关。急流入口区(出口区)南侧主要为西风动量水平通量辐散区(辐合区),北侧为辐合区(辐散区),西风动量水平辐合辐散区的水平尺度只有百公里左右,也属于中尺度范围,并且辐合辐散区一般位于地形坡度较大区域上空。西风动量的垂直输送与西风动量水平通量散度分布几乎一致,但数值小一个量级以上。 相似文献
7.
利用1979—2003年NCEP/NCAR月平均再分析资料, 探讨夏季 (6—8月) 200 hPa东亚西风急流扰动异常与南亚高压和西太平洋副热带高压的关系。研究指出:夏季200 hPa东亚西风急流扰动动能加强 (减弱), 东亚西风急流位置偏南 (偏北)、强度偏强 (偏弱); 东亚西风急流扰动动能强弱不仅与北半球西风急流强弱和沿急流的定常扰动有关, 而且还与东亚地区高、中、低纬南北向的扰动波列有关, 亚洲地区是北半球中纬度环球带状波列异常最大的区域。夏季200 hPa东亚西风急流扰动动能加强 (减弱), 南亚高压的特征为位置偏东 (偏西)、强度加强 (减弱); 西太平洋副热带高压的特征为位置偏南 (偏北)。东亚环流特别是500 hPa西太平洋副热带高压对东亚西风带扰动异常的响应由高空东亚西风急流南侧的散度场及其对流层中下层热带和副热带地区的垂直速度距平场变化完成。 相似文献
8.
淮河流域夏季降水与中高纬波列结构的关系 总被引：2，自引：0，他引：2
利用NCEP/NCAR再分析资料,通过合成分析、诊断分析等方法研究了淮河流域夏季降水异常年份的大尺度环流场,并且分析了造成这种环流背景的可能原因。结果表明:西风急流在多雨年和少雨年作为波导的作用没有变化,但多雨年西风急流的位置比少雨年偏东。在中高纬地区,多雨和少雨年200 h Pa沿西风急流的定常Rossby波列结构有明显的不同。在多雨年,有一条明显的沿西风急流传播的Rossby波列结构,波源位于西欧和中亚,波汇位于里海和我国淮河流域地区,日本以东的西北太平洋也是明显的波源区;在少雨年,西欧和中亚的波源地区的波活动明显减弱,原来位于淮河流域的波汇区南压到长江以南,西北太平洋上的波活动也明显减弱。这种波列结构的不同可能是造成淮河流域夏季降水异常的一个重要原因。 相似文献
9.
2008年初我国南方雨雪低温天气的中期过程分析III：青藏高原-孟加拉湾气压槽 总被引：5，自引：2，他引：3
针对2008年1月24日～2月2日我国南方地区雨雪低温过程,分析了其中期演变特征及其可能机理。在亚非副热带地区,Rossby波能量从北非东北侧传播到东亚地区,引起青藏高原附近气压槽的加深和西太平洋副热带高压的加强及北扩,并与亚洲北部的高压脊配合,造成了这次较长时间的雨雪低温过程。东北大西洋和西欧的反气旋式异常环流为亚非副热带急流Rossby波与欧亚高纬度Rossby波活动的主要波源区。在对流层上层,贝加尔湖一带的高压脊在过程之前已形成,而在这次过程中缓慢减弱,来自上游Rossby波能量主要起抵消摩擦耗散的作用。西太平洋副热带高压在偏北位置上维持主要由来自青藏高原和孟加拉湾地区Rossby波能量的注入所致。亚洲冷高压系统的强度、位置及形态决定了这次我国南方地区低温过程的重要特性。 相似文献
10.
利用1960—2003年NCEP/NCAR再分析和新疆75个气象站月降水资料, 分析了新疆夏季降水与亚洲副热带西风急流的关系, 新疆夏季降水与西亚急流的南北位置和准静止波活动密切联系。通过波作用量的动力学诊断分析, 研究了新疆降水异常年准静止波活动特征, 新疆降水异常年斯堪的纳维亚半岛向东传播的中高纬静止波传播方式的不同, 从而影响沿副热带西亚西风急流传播的静止波活动, 进而影响新疆夏季降水, 并存在沿60°E自南极高纬低层经向上传至低纬对流层顶部, 并在北半球副热带地区转为经向下传至北半球中纬地区的波列, 该波列活动与西亚急流变化联系。 相似文献
11.
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
13.
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
14.
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