2023年11月大气环流和天气分析

2023年11月北半球大气环流的主要特征是:极涡呈多极型分布,与历史同期相比,主体强度显著偏强;中高纬度地区环流形势为“四槽四脊”,亚洲中高纬度地区环流整体呈西高东低型,但东亚大槽偏弱;副热带高压强度显著偏强。11月全国平均气温较常年同期(3.3℃)偏高0.5℃。全国平均降水量较常年同期(20.2 mm)偏多9%,降水显著偏多地区主要在内蒙古、东北地区、华北南部和黄淮北部,东北部分地区降水量突破历史同期极大值。月内冷空气活动较为频繁,大气扩散条件整体较好,中东部等地较少出现雾和霾天气。月内出现了2次北方型寒潮天气过程。     

2017年3月大气环流和天气分析

2017年3月大气环流的主要特征是极涡偏强且呈单极型分布,中高纬环流呈4波型,西太平洋副热带高压强度较常年偏弱,南支槽强度较常年偏强。3月全国平均气温4.5℃,较常年同期偏高0.4℃;全国平均降水量36.2 mm,比常年同期（29.5 mm）偏多22.7%。月内我国东部地区有2次中等强度冷空气过程;南方地区有3次区域性暴雨天气过程;北方地区有2次沙尘天气过程;江苏、湖南等省局地遭受风雹袭击。     

2011年11月大气环流和天气分析

2011年11月大气环流主要特征是：北半球极涡呈单极性分布,主体位于北极圈内,强度和常年同期接近。中高纬呈4波型,其中欧洲大槽强度较常年偏强,位置偏东;东亚大槽强度偏弱,且位置偏东,这不利于引导冷空气影响我国,月内我国出现了5次主要的冷空气过程,11月全国平均气温为3.9℃,比常年同期（2.1℃）偏高1.8℃。南支槽位于100°E附近,强度接近常年,副高的位置偏西,有利西南暖湿空气向我国的输送。11月,我国出现6次主要的降水过程,全国平均降水量为28.3mm,较常年同期（18.0 mm）偏多57.3%,为近20年来的最大值。北方大部地区降水较常年偏多,其中西北地区东部、内蒙古南部、华北西部、江南东南部和华南中东部较常年同期偏多2倍以上。     

2013年11月大气环流和天气分析

2013年11月大气环流主要特征是：北半球极涡呈单极型分布,主体位于北极圈内,强度较常年同期偏强;欧亚中高纬环流经向度较小;南支槽平均位置大致位于80°E附近,同时,副热带高压较常年同期偏强,位置偏西、偏北。11月,全国平均降水量为22.5 mm,较常年同期（18.8 mm）偏多19.7%。全国平均气温为3.6℃,较常年同期（2.9℃）偏高0.7℃。月内,我国出现3次冷空气过程和6次较强降水过程。东北地区出现了两次强降雪过程,部分地区出现暴雪到大暴雪;台风海燕给华南地区带来较大风雨影响;北方冬麦区及江南大部出现明显降水,干旱缓解;由于冷空气势力弱,中东部地区雾霾天气频发,全国平均雾霾日数为4.3天,为1961年以来历史同期最多。     

2021年11月大气环流和天气分析

2021年11月大气环流的主要特征为:北半球极涡显著偏强,欧亚中高纬环流呈纬向多波动型,冷空气活跃,东亚大槽和西太平洋副热带高压均偏西偏强.11月,全国平均降水量为23.8 mm,比常年同期(18.8 mm)偏多26.7％;全国平均气温为2.9℃,与常年同期持平.月内气温冷暖起伏较大,出现了2次全国型寒潮过程和3次大范...     

2012年3月大气环流和天气分析

2012年3月大气环流主要特征是:北半球极涡呈多极型分布,强度较常年同期略偏强;中高纬度环流呈4波型分布,中低纬地区南支槽略偏强,有利西南暖湿空气向我国的输送;西太平洋副热带高压强度偏弱。3月全国平均气温为3.5℃,比常年同期(3.8℃)略偏低0.3℃。全国平均降水量为31.4 mm,较常年同期(28.9 mm)偏多8.7%。月内我国出现了3次主要的冷空气过程,北方出现今年首次沙尘天气过程,南方持续低温阴雨天气。     

2019年1月大气环流和天气分析

2019年1月大气环流主要特征为：北半球极涡呈偶极型分布,环流呈三波型,南支槽平均位置大致位于90°E附近,同时,西太平洋副热带高压较常年同期位置偏西,强度偏强。本月,全国平均降水量为14.0 mm,较常年同期（13.5 mm）偏多4%,月内出现三次较强降水过程,江南和西南部分地区降水明显,全国共有35站日降水量达到极端事件标准。全国平均气温为-4.1℃,较常年同期（-5.0℃）偏高0.9℃,共出现4次冷空气过程。本月共发生2次大范围雾 霾天气过程。     

2012年4月大气环流和天气分析

2012年4月大气环流特征为:北半球极涡呈单极型分布,强度接近常年;中高纬度环流呈4波型分布,乌拉尔山阻塞高压尤其偏强,有利于冷空气影响我国;中低纬度地区南支槽前多波动,西太平洋副热带高压强度稍偏强。4月全国平均温度为11.7℃,较常年同期(10.7℃)偏高1.0℃。全国平均降水量为45.6 mm,较常年同期(43.1 mm)偏多2.5 mm(偏多5.8%)。月内我国共出现了8次大到暴雨降水过程,华南、江南多强对流并伴随雷暴大风和冰雹天气,北方出现6次沙尘过程。     

2013年12月大气环流和天气分析

2013年12月大气环流主要特征是：极涡呈偶极性分布,中心气压均较常年平均偏低,欧亚中高纬环流呈两槽一脊型;南支槽较活跃,平均位置大致位于90°E附近,副热带高压较常年同期偏强,位置偏西、偏北。12月,全国平均降水量为15.4 mm,较常年同期（10.5 mm）偏多46.7%;但地区差异较大,南方较常年同期偏多2~4成,淮河以北偏少,其中华北、黄淮等地几乎无降水。全国平均气温为-2.8℃,较常年同期（-3.2℃）偏高0.4℃;就区域来看,呈现“北暖南冷”的特征。月内,我国出现3次主要的冷空气过程和1次主要的降水过程。南方地区中旬出现一次大范围强降水和持续低温天气;中东部地区分别于上旬和下旬各出现一次雾霾天气。     

2017年4月大气环流和天气分析

2017年4月大气环流的主要特征是极涡呈偶极型分布,强度偏弱,中高纬环流呈4波型分布,西太平洋副热带高压强度较常年偏强,南支槽强度与常年相当。4月全国平均气温为12.0℃,较常年同期偏高1.0℃;全国平均降水量为44.0 mm,较常年同期偏少2%。月内出现1次全国大范围较强冷空气过程;南方多降水天气,共出现3次区域性暴雨天气;北方出现2次扬沙天气;多省(区、市)局地遭遇风雹灾害。     

CHARACTERISTICS AND TRENDS OF CLIMATIC EXTREMES IN CHINA DURING 1959–2014

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.     

Revisiting the Concentration Observations and Source Apportionment of Atmospheric Ammonia

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     

LOW-FREQUENCY CIRCULATION AND EXTENDED-RANGE FORECAST IN CONNECTION WITH AUTUMN EXTREME HEAVY RAINFALL PROCESS IN HAINAN

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.     

AN ATTRIBUTION ANALYSIS OF CHANGES IN POTENTIAL EVAPOTRANSPIRATION IN THE BEIJING–TIANJIN–HEBEI REGION UNDER CLIMATE CHANGE

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.     

ANALYSIS OF “BIMODAL PATTERN” STORM ACTIVITY CHARACTERISTICS OF THE BAY OF BENGAL

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.     

Information for Authors

正AIMS AND SCOPE Atmospheric and Oceanic Science Letters (AOSL) publishes short research letters on all disciplines of the atmosphere sciences and physical oceanography.     

Information for Authors

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.     

Information for Authors

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.     

INFORMATION FOR AUTHORS

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.