一次暴雨过程中不同暴雨带的降雨特征及其成因分析

使用常规观测资料和FY-2E卫星云图、自动气象站和雷达等非常规观测资料,对2016年5月19-20日广西东部四条暴雨带的降雨特征和成因进行分析。结果表明:此次大范围暴雨与高低层天气系统的配置及冷暖空气的活动密切相关,但出现在桂东的四条暴雨带的降雨特征及成因有所不同:河池东部到桂林南部和贺州北部一带的东西向暴雨带(雨带I)为持续时间长的东西向窄带、锋面附近中小尺度对流系统南北少动是其直接原因;来宾到贺州南部(雨带II)的强降雨区偏在其东段、是由冷空气加速南下导致的锋面对流系统转向造成;南宁-玉林暴雨区(雨带III)和防城港-北海暴雨区(雨带IV)的出现都与锋面对流系统和暖区对流系统的合并发展有关,但雨带III的对流系统发展更为旺盛、持续时间更长,因此暴雨区范围最广、强度最强。     

广西气象台站及时报准2号台风、服务积极主动

台风预报服务是汛期气象服务工作中一项十分重要的工作。今年第2号台风广西气象部门预报及时准确,服务积极主动,受到了地方党政领导部门的赞扬。 今年2号台风是由6月14日在南海南部生成的热带低压发展而成的,18日15时左右在南海北部发展成台风,19日10时在广东省电白县的电城镇附近登陆,18时左右进入广西玉林地区南部,22时到达横县,20日05时移至武鸣县附近,09时消失于平果县。在2号台风影响下,广西玉林、钦州、南宁三地区普降暴雨到大暴雨,局部特大暴雨,玉林地区南部出现了7—8级、阵风11级的大风。由于气象部门预报及时准确、服务积极主动,各级党政部门、领导高度重视,采取了     

2017年盛夏湖南持续性暴雨过程的水汽输送和收支特征分析

利用NCEP/NCAR再分析资料,首先分析了2017年6月下旬至7月初湖南持续性暴雨天气过程的环流背景和大尺度水汽输送特征,然后引入NOAA的轨迹模式HYSPLIT,分阶段定量分析了暴雨的水汽输送特征以及区域水汽收支情况。结果表明：天气系统的有效配置和稳定维持是强降雨持续的主要原因,持续性暴雨与全球范围的水汽输送和水汽辐合相联系,低空急流的演变和进退与暴雨落区和强度的演变关系密切。影响此次强降水过程的水汽通道主要有三支,第一支由索马里越赤道急流经孟加拉湾和我国西南地区输入暴雨区,第二支由印度洋中东部越赤道气流经孟加拉湾南部和南海北部输入暴雨区,第三支由来自南半球的越赤道气流自南海南部一路北上输入暴雨区,第三阶段还有一支水汽由赤道西太平洋穿越菲律宾进入南海后再北上输入暴雨区。过程第一、二阶段的水汽输送主要来自孟加拉湾,其次是南海,第三阶段来自孟加拉湾和南海（包括西太平洋）的水汽输送各占一半。受地形影响,孟加拉湾通道的水汽主要输送至暴雨区700 hPa,其他来自低纬洋面的通道水汽主要输送到850 hPa及以下各层。暴雨区水汽输入主要来自南边界和西边界,且主要由低层输入暴雨区,以水平水汽通量辐合的形式在暴雨区上空低层大量汇聚,经由强烈的垂直上升运动输送至对流层中高层积累和凝结,从而导致降水的产生,降水的强弱与边界水汽输入和区域水汽辐合的强弱变化一致。     

SST与广西汛期降雨关系的分析

利用1957—1978年(共22年)海温(SST)网格点资料,分别计算(11月至次年2月)SST距平与广西桂林、柳州、河池、梧州、南宁、百色、玉林、北海八站汛期降水距平百分率的相关系数,就海温变异与广西汛期降水的关系作了一次较全面的普查。结果表明秋,冬季SST影响来年广西降雨最明显的海域是西北太平洋、西太平洋低纬“海洋大陆”以北、菲律宾以东海域,南海北部、北部湾,阿拉伯海以南海面和赤道东太平洋SST与广西降水也有一定联系。文中对此种相关机理作了一些初步分析。     

SST与广西汛期降雨关系的分析

利用1957—1978年(共22年)海温(SST)网格点资料,分别计算(11月至次年2月)SST距平与广西桂林、柳州、河池、梧州、南宁、百色、玉林、北海八站汛期降水距平百分率的相关系数,就海温变异与广西汛期降水的关系作了一次较全面的普查。结果表明秋,冬季SST影响来年广西降雨最明显的海域是西北太平洋、西太平洋低纬“海洋大陆”以北、菲律宾以东海域,南海北部、北部湾,阿拉伯海以南海面和赤道东太平洋SST与广西降水也有一定联系。文中对此种相关机理作了一些初步分析。     

我区台站研制天气预报专家系统简介

我区对天气预报专家系统的研制,首先由区气象台自1985年开始研制,紧接着区气科所、河池、柳州、钦州、北海、南宁、玉林、桂林等地区气象台以及个别县站也都进行了研制,并取得了不同程度的成功,有力地推动了预报业务工作的现代化建设,同时,启迪并激发了我区气象科技工作者开发、应用微机的信心。 目前我区天气预报专家系统以地区性灾害性天气为主,如春播期低温阴雨及倒春寒、汛期暴雨、台风、冰雹等,至今建成或初步建成了14项,有的已达到相当先进的水     

初夏五月温高、雨多、洪涝少

今年五月我区大部气温偏高,1日、2日和23日分别出现了22站、44站、34站最高气温≥35℃的高温天气,锋面活动频繁,低涡活动多,我区大部雨水偏多。月雨量:玉林地区,桂林、柳州、河池、梧州、钦州五地区大部及百色地区南部、南宁地区北部为249～582毫米,其它地区90～246毫米。与常年相比,玉林地区,柳州、桂林、南宁、钦州四地区大部偏多2～9成,其中平南、玉林、横县、邕宁、钦州五县市及涠洲岛偏多1.2～1.8倍,其余地区大部偏少1～5成。 主要降雨过程有八次,分别为:4～7     

广西暴雨非均匀性分布特征研究

利用广西1979—2008 年83 个气象观测站的逐日降水和NCEP/NCAR 再分析资料,采用蒙特卡罗检验等方法,计算和分析广西暴雨非均匀性分布及其变化特征。结果表明,广西暴雨主要发生在汛期(4—9 月),暴雨总站次约占全年总数的9 成;年暴雨量占全年总降水量的比例随年际变化有增加的趋势,即以后发生极端强降水的可能性增大。广西暴雨集中度分布为桂东大于桂西,桂西北和沿海地区的暴雨集中度变化趋势大部分为正趋势,桂东南大部分为负趋势。桂东北和西南地区暴雨集中期最晚,百色北部山区和桂东南地区最早,暴雨集中期气候趋势是桂东大部分地区和沿海地区有偏晚趋势,桂中和桂西大部分地区有偏早趋势。冬春季青藏高原南部和西太平洋高度场负距平,夏秋季副热带高压偏强、面积偏大、脊线偏西,这种稳定的东高西低形势有利于广西暴雨集中度偏大。冬季青藏高原南部和西太平洋地区的高度场均为正距平,春夏秋季青藏高原南部及西太平洋高度场的周期性变化特征使广西暴雨集中度偏小。夏季风强(弱)的年份孟加拉湾向广西输送的水汽通量少(大),低空风速小(大),造成广西除了北部山区和北海以外大部分地区暴雨集中度偏小(大)。      

广西“94·6”特大暴雨洪涝灾害气象工作情况总结

广西“９４·６”特大暴雨洪涝灾害气象工作情况总结广西气象局业务处１９９４年６月１２—１７日，我区出现了一次范围广、强度大、持时长的暴雨、特大暴雨天气过程，致使柳江、桂江、西江水位暴涨，桂林地市、柳州地市、河池地区、梧州地市及玉林地区沿江县市遭受建国后...     

钦州沿海1997年汛期暴雨预报浅析

通过分析钦州沿海１９９７年汛期１４个暴雨过程知道,该年汛期暴雨具有次数多、量级小的特点,其主要影响系统是锋面、切变线;７００ｈＰａ层低能舌叠置在８５０ｈＰａ相对高能区上,在钦州沿海形成位势不稳定区,是整个汛期暴雨具有显著的共同的前期特征。     

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.     

Could the Recent Taal Volcano Eruption Trigger an El Ni?o and Lead to Eurasian Warming?

正The Taal Volcano in Luzon is one of the most active and dangerous volcanoes of the Philippines. A recent eruption occurred on 12 January 2020(Fig. 1a), and this volcano is still active with the occurrence of volcanic earthquakes. The eruption has become a deep concern worldwide, not only for its damage on local society, but also for potential hazardous consequences on the Earth's climate and environment.     

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.     

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.     

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     

COMPARATIVE ANALYSIS OF VARIOUS DATA OF AIR–SEA TEMPERATURE DIFFERENCE AND ITS VARIATION ACROSS SOUTH CHINA SEA IN THE PAST 35 YEARS

Using the International Comprehensive Ocean-Atmosphere Data Set(ICOADS) and ERA-Interim data, spatial distributions of air-sea temperature difference(ASTD) in the South China Sea(SCS) for the past 35 years are compared,and variations of spatial and temporal distributions of ASTD in this region are addressed using empirical orthogonal function decomposition and wavelet analysis methods. The results indicate that both ICOADS and ERA-Interim data can reflect actual distribution characteristics of ASTD in the SCS, but values of ASTD from the ERA-Interim data are smaller than those of the ICOADS data in the same region. In addition, the ASTD characteristics from the ERA-Interim data are not obvious inshore. A seesaw-type, north-south distribution of ASTD is dominant in the SCS; i.e., a positive peak in the south is associated with a negative peak in the north in November, and a negative peak in the south is accompanied by a positive peak in the north during April and May. Interannual ASTD variations in summer or autumn are decreasing. There is a seesaw-type distribution of ASTD between Beibu Bay and most of the SCS in summer, and the center of large values is in the Nansha Islands area in autumn. The ASTD in the SCS has a strong quasi-3a oscillation period in all seasons, and a quasi-11 a period in winter and spring. The ASTD is positively correlated with the Nio3.4 index in summer and autumn but negatively correlated in spring and winter.     

Analysis of Atmospheric Boundary Layer Height Characteristics over the Arctic Ocean Using the Aircraft and GPS Soundings

正ERRATUM to: Atmospheric and Oceanic Science Letters, 4(2011), 124-130 On page 126 of the printed edition (Issue 2, Volume 4), Fig. 2 was a wrong figure because the contact author made mistake giving the wrong one. The corrected edition has been updated on our website. The editorial office is sincerely sorry for any     

Index to Vol.31

正AN Junling;see LI Ying et al.;(5),1221—1232AN Junling;see QU Yu et al.;(4),787-800AN Junling;see WANG Feng et al.;(6),1331-1342Ania POLOMSKA-HARLICK;see Jieshun ZHU et al.;(4),743-754Baek-Min KIM;see Seong-Joong KIM et al.;(4),863-878BAI Tao;see LI Gang et al.;(1),66-84BAO Qing;see YANG Jing et al.;(5),1147—1156BEI Naifang;