共查询到20条相似文献，搜索用时 78 毫秒
1.
2021年秋季,我国气候总体呈现气温偏高、降水偏多的特点.季内降水总体表现出"北多南少"的空间分布特征,华西秋雨异常偏强.对北方地区降水阶段性异常偏强的成因分析表明,9月至10月上旬,欧亚中高纬度环流呈"西低东高"型分布,贝加尔湖—巴尔喀什湖为显著低槽区,西太平洋副热带高压持续偏强、偏大、西伸明显,秋季前期异常偏北,有... 相似文献
2.
印度洋偶极子和华西秋雨的关系 总被引：6，自引：0，他引：6
《高原气象》2015,(4)
利用统计方法对印度洋偶极子(Indian Ocean Dipole,IOD)与华西秋雨的关系进行分析。结果发现:(1)相对于IOD的季节锁相特征,华西秋雨与印度洋偶极子指数(Indian Ocean Dipole Index,IODI)相关性也呈现相应的变化特征:春、夏季正相关发展、范围扩大;秋季稳定且正相关性较高,与夏季时滞相关较为一致;前期冬季减弱并呈反相关关系。(2)对印度洋偶极子时期异常环流场、水汽场以及射出长波辐射(Outgoing Longwave Radiation,OLR)场特征分析发现,IOD正位相年,500 h Pa高度场距平在冬、春季为负异常,春、秋季西太平洋副热带高压偏强、偏北,且夏季华西区域受中层异常浅槽的西南气流影响,850 h Pa经向风合成在冬、春季以负异常为主,夏、秋季转为正异常,且华西区域秋季为异常气旋性环流控制,赤道印度洋低空东风异常,这些异常环流都利于华西区域降水偏多,并对偶极子的延续起到作用。(3)正位相年,冬、春季华西大部区域为水汽辐散区,夏、秋季四川东北部及黔渝大部为水汽辐合区,水汽输送依靠孟湾西南气流和西太平洋副热带高压外围的偏东气流完成。(4)对应于印度洋海温正(负)异常,秋季华西区域上空的热状况异常分布将使其大气对流增强(减弱)。因此,夏季IOD异常位相为华西秋雨预报提供了一个有用的前期信号,而秋季IOD正位相则对华西秋雨的发生发展起到较好的延续作用。 相似文献
3.
根据国家气象信息中心提供的中国台站气温、降水资料,NCEP/NCAR逐日大气环流再分析资料和NOAA提供的月平均海温资料,分析了2017年秋季我国北方地区降水异常偏多的成因。结果表明2017年秋季我国降水阶段性特征明显,9—10月北方地区降水异常偏多主要受东亚环流型组合异常的影响。东亚500 hPa高度距平场从高纬至低纬呈“+-+”的异常分布,极区高度场偏高,极涡分裂偏向东北亚地区,贝加尔湖 巴尔喀什湖地区为显著低槽区,西太平洋副热带高压较常年偏强偏西偏北,有利于华西秋雨偏强。此外,850 hPa距平风场上朝鲜半岛的反气旋式环流异常有利于引导偏东路径的冷湿气流输送至黄河与长江之间的地区,与来自孟加拉湾和南海的暖湿气流交汇,形成水汽通量异常辐合区,造成黄淮及江淮等地降水异常偏多。进一步诊断表明热带中东太平洋海温秋季转为偏冷状态,热带太平洋地区Walker环流明显增强,有利于西太平洋副热带高压偏强西伸偏北;9—10月热带印度洋偶极子维持正位相有利于在孟加拉湾形成反气旋式环流异常,并同样有利于副热带高压西伸偏北。因此,海温外强迫信号的影响加上中高纬环流异常的共同作用造成9—10月东亚环流型异常特征,并进一步导致我国北方地区降水异常偏多。 相似文献
4.
华西秋雨区域性极端降水的环流特征 总被引：8，自引：2，他引：6
利用1961—2010年中国743个测站的逐日降水资料和NCEP/NCAR再分析资料,采用百分位方法挑选出了发生在华西秋雨期(8月9日—10月12日)的161次区域性极端降水事件,将其分为两类分别讨论了同期和前期的异常环流特征,并与一般性降水进行了对比。结果表明,对于第一(二)类极端降水,华西地区气旋性距平环流(气旋性风切变)形成低层风场辐合,同时高层为辐散,由此产生强烈的上升运动,来自热带海洋的水汽输送偏强(偏弱),在华西秋雨区形成水汽辐合,副热带高压位置偏西、偏北使得华西地区西南暖湿气流偏强,巴尔喀什湖以北地区为正(负)高度异常,形成一槽一脊(二槽一脊)环流型,西北气流由此加强,冷暖空气交汇于华西地区从而形成极端降水。两类极端降水均与一般性降水具有相似的异常环流特征,只是造成极端降水的异常环流强度均比一般性降水更强。两类极端降水的上述异常环流型在极端降水发生前一天就已经存在,可以作为华西秋雨极端降水短期预测的强信号。 相似文献
5.
2017年秋季华西秋雨的多时间尺度变化特征及成因分析 总被引：1，自引：0，他引：1
利用我国723个常规观测气象站降水资料和NCEP再分析资料等,综合大气环流的季节内 季节异常、海洋外强迫年际异常及降水的长期变化影响,分析了2017年华西秋雨异常的成因。结果表明：20世纪60年代以来,华西秋雨存在3~4、6~9、12~18 a、36 a等多个时间尺度的准周期变化,并自1990年以来呈现增加的长期变化趋势。2017年华西秋雨异常偏多是多时间尺度变率叠加影响的结果。2017年秋季,北半球极涡偏向东亚地区,贝加尔湖低槽多冷空气分裂南下,西太平洋副热带高压异常偏强偏西,华西地区处于水汽输送异常辐合大值区,出现降水异常偏多。在季节内时间尺度上,东亚夏季风的季节内撤退过程偏慢,夏季风北界位置持续偏北,9—10月主雨带维持在华西—江汉—江淮一带。自西太平洋经南海北上的水汽输送的季节内变化,并与东北冷涡的季节内活动相配合,是造成华西秋汛的季节内环流影响因子。华西秋雨年际异常与赤道中东太平洋海温呈现显著的负相关。夏末秋初开始发展的拉尼娜状态是2017年我国秋季降水异常的重要外强迫因子。2017年华西秋雨的异常偏多也与其近年来的年代—多年代际正距平位相及长期增加趋势相关联。 相似文献
6.
2014年秋季我国华西地区降水异常的成因分析 总被引：4，自引：4，他引：0
2014年秋季,全国平均降水量较常年同期偏多,其中华西地区降水偏多明显。季内,我国华西地区降水阶段性变化显著。分析表明,秋季华西地区降水偏多可能与热带印度洋海温偏高有关。印度洋海温偏高,一方面有利于西北太平洋地区对流层低层异常反气旋式环流的发展和东南水汽输送的加强,另一方面印度洋海温的偏高有利于印度洋地区对流的活跃和西南水汽输送的加强。在中高纬地区,贝加尔湖地区为异常低槽区,易引导冷空气南下影响我国华西地区。同时,西太平洋副热带高压强度偏强及西伸脊点的偏西,综合导致华西地区秋季降水偏多。而华西地区降水的季内变化与西太平洋副热带高压的异常活动有关。 相似文献
7.
《干旱气象》2021,(2)
利用1971—2017年华西秋雨南区269个气象站逐日降水资料和NCEP/NCAR再分析资料等,分析华西南区秋雨强度变化及其大气环流异常特征,寻找影响华西南区秋雨强度的大气冷源关键区,并就关键区大气冷源对南区秋雨强度的影响进行诊断。结果表明:华西南区秋雨强度整体变化趋势不显著,其年际变化可能受前期冬季(1月)青藏高原大气冷源异常变化的滞后影响。当前期冬季高原冷源偏强(弱)时,可激发南海到西太平洋一带气旋(反气旋)性异常环流并持续到夏季,其南侧持续偏西(东)气流使得赤道西(中)太平洋地区表层暖水东(西)传,造成赤道中太平洋地区海温暖(冷)异常,继而在其西北侧西太平洋地区激发气旋(反气旋)性环流,华西地区处于该环流西侧的偏北(南)风控制下,水汽条件较差(好),降水偏少(多),华西南区秋雨偏弱(强)。 相似文献
8.
北半球秋季欧亚遥相关与华西秋雨的关系 总被引：2，自引：0，他引：2
利用EOF、相关分析、合成分析等常规统计方法研究华西秋雨与秋季欧亚遥相关(EUa)的关系。结果表明:北半球秋季欧亚遥相关(EUa)指数与华西秋雨呈显著的负相关,两者具有一致的阶段性特征。以1986年为界,20世纪80年代中期之前华西秋雨与EUa指数相关系数波动较大,均在-0.4以上,显著相关区主要集中于四川盆地西南部、贵州大部;20世纪80年代中期之后两者相关系数呈显著增加趋势,且显著相关区域向北偏移,主要集中于四川东北部、重庆大部以及陕西南部地区。EUa异常与华西秋雨的多寡关系显著。EUa正异常年,中高纬度环流形势与水汽特征有利于华西秋雨北部地区降水发生,华西秋雨南部地区缺乏水汽,动力条件不足,不利于秋雨偏多。EUa负异常年,华西秋雨东部地区,表现为有利于降水偏多,而西部地区则特征相反。 相似文献
9.
利用MICAPS常规资料和NCEP再分析资料,对2013年7月辽宁省降水异常物理机制进行了研究。结果表明:2013年7月辽宁省降水偏多发生在异常环流背景下,乌拉尔山高压脊和贝加尔湖低压槽强度大于常年,冷空气偏强且路径偏南;东亚40°—50°N处在纬向强锋区中,有利于气旋生成发展;副热带高压脊线比常年偏北2个纬度,西北侧暖湿气流活跃。7月中高纬地区有3次明显冷空气向南侵入至40°N,与中低纬北上至40°N及以北的暖湿气流交绥形成暴雨,影响系统分别为华北气旋、蒙古气旋冷锋和副热带高压西侧辐合线,不同影响系统暴雨过程的物理机制存在差异。3次暴雨过程中,华北气旋暴雨水汽供应最充沛,水汽源地不仅有西太平洋、南海、东海和黄海,还有孟加拉湾;暴雨区水汽主要由副热带高压外围西南或偏南气流向北输送,东海北部和黄海是水汽汇合及输送量最大的区域。高空急流受贝加尔湖低槽强度影响,不同影响系统高空急流演变和强度不同,低空急流分布与强度及高空辐散区、低空辐合区相对高、低空急流轴分布的位置也不同;高、低空急流耦合发展及高空辐散区、低空辐合区叠置产生的强垂直上升运动造成了水汽强烈辐合,其中华北气旋暴雨水汽辐合最强,水汽辐合层顶达850hPa,蒙古气旋冷锋和副热带高压西侧辐合线暴雨水汽辐合顶在900hPa附近及以下。热力分析表明,3次暴雨过程环境大气中层均有干冷空气侵入,增加了降水对流的不稳定性。 相似文献
10.
利用华西地区72个站点1959~2013年秋季(9~11月)降水资料和NCEP/NCAR再分析资料,通过EOF、REOF、MK检验、二阶函数拟合分析、小波分析、合成分析等方法将华西秋雨区划分为南北两个显著区,并对各区域秋雨的时空分布以及旱涝特征进行了详细分析。结果表明:南北两个秋雨区既有共同特征又有个性差异;两者发生突变年份具有明显的一致性,均发生在20世纪80年代中期,年际均存在准6年周期变化,且80年代中期以后南北两个气候区均由年代际降水偏多期转入年代际降水偏少期,但两个秋雨区减少趋势存在明显差异,南区减少较北区显著;北区自2000年后秋雨年际波动明显,秋季降水有缓慢上升趋势,年代际长周期有所差异。影响关键区旱涝特征的大气环流形势与水汽输送特征也存在显著差异,北部型陕甘南区与中高纬度环流系统、北部冷空气以及来自孟加拉湾与西太平洋地区的两支水汽输送通道密切相关,南部型则主要与印缅槽、南支槽的异常活动以及孟加拉湾的水汽输送更为相关。 相似文献
11.
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
12.
Yuepeng PAN Mengna GU Yuexin HE Dianming WU Chunyan LIU Linlin SONG Shili TIAN Xuemei Lü Yang SUN Tao SONG Wendell W. WALTERS Xuejun LIU Nicholas A. MARTIN Qianqian ZHANG Yunting FANG Valerio FERRACCI Yuesi WANG 《大气科学进展》2020,37(9):933-938
正While China’s Air Pollution Prevention and Control Action Plan on particulate matter since 2013 has reduced sulfate significantly, aerosol ammonium nitrate remains high in East China. As the high nitrate abundances are strongly linked with ammonia, reducing ammonia emissions is becoming increasingly important to improve the air quality of China. Although satellite data provide evidence of substantial increases in atmospheric ammonia concentrations over major agricultural regions, long-term surface observation of ammonia concentrations are sparse. In addition, there is still no consensus on 相似文献
13.
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
14.
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
15.
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
16.
《大气和海洋科学快报》2013,(4):227
正AIMS AND SCOPE Atmospheric and Oceanic Science Letters (AOSL) publishes short research letters on all disciplines of the atmosphere sciences and physical oceanography. 相似文献
17.
《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
18.
《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
19.
20.
《大气科学进展》2014,(6)
正Aims Scope Advances in Atmospheric Sciences(AAS)is an international journal on the dynamics,physics,and chemistry of the atmosphere and ocean with papers across the full range of the atmospheric sciences,co-published bimonthly by Science Press and Springer.The journal includes Articles,Note and Correspondence,and Letters.Contributions from all over the world are welcome. 相似文献