旱,涝年与海气相互作用

利用１９５１￣１９９１年５００ｈＰａ高度场和海温场以及１９８０￣１９９１年ＴＢＢ资料，采用合成分析方法研究了东亚季风区季节转换在旱、涝年的不同特征。发现旱、涝年海温场分布型的不同及其形成的海气相互作用的差异使得西太平洋副热带高压在涝年季节北进较平缓，其脊线位置稳定在２５°Ｎ左右，强度较强，从而导致夏季风雨带在江淮流域停滞，形成江淮洪涝。中还讨论了中南半岛对流和赤道干旱带的变化对江淮流域旱、涝的先     

南海热带对流季节内振荡对江淮流域旱涝影响的初步分析

使用TBB17年逐月、候平均资料和欧亚500hPa候平均高度距平场,计算了南海地区逐月TBB的标准差,分析其时空分布特征。采用带通滤波方法,分析了江淮流域旱(1985年)、涝(1991、1998年)年南海地区TBB季节内振荡及其经向传播特征。结果表明,江淮流域涝年,南海地区TBB30～60d和10～20d振荡十分活跃,向北传播非常明显。当TBB强对流位相传播到30°N附近的副热带地区时,激发其对流扰动加强,造成江淮流域集中暴雨。而旱年则相反。南海和30°N地区对流活动的强弱差异与500hPa候平均高度距平场的遥相关揭示出江淮流域旱涝年波列结构有很大的不同。     

江淮流域梅雨期降水的空间非均匀分布与前期海温的关系

利用中国气象局提供的1978-2007年全国753站逐日降水资料、NECP/NCAR提供的逐日再分析资料和NOAA提供的第2套扩展重建海温资料,从区域整体角度确定了近30 a（1978-2007年）江淮流域梅雨期.采用EOF（empirical orthogonal function,经验正交函数）分析,讨论了江淮流域梅雨期降水空间非均匀分布特征,着重研究了影响江淮梅雨空间非均匀分布的前期海温关键区及关键时段.结果表明：全区一致梅雨旱涝与前期冬季北太平洋鄂霍次克海附近的海温异常有密切的联系.当前期冬季该海域海温偏高时,冬季风偏弱,对应后期梅雨一致偏涝,反之则偏旱.5月南海至台湾和菲律宾以东附近海温偏低,江淮流域梅雨量偏多,反之则偏少.梅雨的南北反相分布与前期秋冬季中印度洋的海温有非常密切的关系,当前一年10月至当年1月中印度洋海温偏高时,梅雨期850 hPa江淮之间易形成切变线,有利于梅雨区“南旱北涝”,反之则“南涝北旱”.梅雨的东西反相分布与前期秋、冬季热带中东太平洋的海温关系密切,ENSO事件有可能通过影响西太平洋副热带高压的东西位置,从而引起东亚大气环流异常,导致梅雨东西分布反相.前期秋季和冬季热带中东太平洋海温偏高年（对应ENSO暖事件）,西太副高位置偏西,有利于梅雨区“东旱西涝”,反之则“东涝西旱”.     

近50年华南前汛期降水、江淮梅雨和华北雨季旱涝特征对比分析

利用全国160站逐月降水资料,统计分析了1951～2000年50年华南前汛期降水、江淮梅雨和华北雨季旱涝事件的分布特征,结果表明:近50年无论是华南前汛期降水、江淮梅雨还是华北雨季,旱(涝)事件频率相当,华南和江淮洪涝强度大于干旱强度,华北干旱与洪涝强度相当,华南前汛期降水和华北雨季总体呈趋旱的趋势,而江淮梅雨呈趋涝的趋势;华南前汛期降水年际变化最为显著,江淮梅雨次之,华北雨季最弱,年代际变化的情况正好相反;从同期500 hPa高度场来看,华南前汛期降水多少与其北侧有无低值系统向南发展关系密切,江淮梅雨和华北雨季均与副高相关显著,不同在于前者还和鄂霍茨克阻塞高压呈显著正相关,而后者受其西北侧中高纬地区的环流影响较大;从前期海温来看,华北雨季与大西洋西部和北太平洋海温关系比华南前汛期降水和江淮梅雨更为密切,江淮梅雨与中国近海海温相关关系最为显著,而华南前汛期降水与孟加拉湾附近海温相关最明显.     

赤道东太平洋海温与我国江淮流域夏季旱涝的成因分析

对赤道东太平洋和西太平洋暖池海温与江淮流域夏季降水的关系作功率谱分析和相关分析.指出秋冬季增暖的厄尔尼诺事件对应江淮流域夏季降水偏多, 春夏季开始发展的ENSO事件江淮流域夏季降水偏少.对两种在不同季节增暖的ENSO事件对应的异常流场特征及其对江淮流域降水的影响用1991年和1994年实例作对比分析.不同季节增暖的ENSO事件在太平洋热带地区环流调整的不同阶段可能是影响夏季风活动和东亚夏季天气气候异常的主要原因.     

黑潮地区海温影响南海夏季风爆发日期的数值试验

采用合成分析和相关分析等方法讨论了季节转换时期（４～６月）黑潮地区海温异常同海夏季风爆发时间和西太平洋副高位置与强度的影响。教值模拟结果进一步表明,该地区海温正针导致西太平洋副高位置偏南,强度偏强,南海夏季风建立较晚,弱度偏北 ,江淮流流域偏涝;反之亦然。     

江淮流域大气水分特征与旱涝关系的诊断分析

本文利用全国125个探空台站1980年(涝年)和1985年(旱年)的一日二次的探空资料计算了江淮流域大气中的水汽通量。通过对其年变化规律的分析,揭示了旱、涝年份水汽输送的特点。结果表明:大气中的水汽输送对于旱涝形成有着重大影响,旱、涝年份的水汽输送场存在明显的差别。夏涝年,水汽输送最大中心及雨带均停留在江淮一带。而夏早年,水汽输送最大中心及雨带则明显偏北。并且发现,在水汽输送场上的可降水量最大中心、水汽辐合带及水汽辐合量最大中心也与雨带有很好的一致性。     

东亚冬季风异常与江淮流域夏季旱涝的关系

从探讨我国江淮流域夏季旱涝成固和预报方法出发，研究它们前期大尺度环流特别是冬季风特征的差异。在1951～1991年中选取江淮流域旱、涝各10个个例，对它们前冬的西风带环流，低纬大尺度风场，垂直环流特征等进行了对比分析。结果给出了冬、夏环流和天气之间相互联系的有力的证据，同样也为夏季旱涝的长期预报提供有意义的物理基础。     

肇庆前汛期异常旱涝的大气环流及海温场特征

从1954~2003年肇庆6个站点的降水资料,按异常旱、涝年的划分标准,统计出30年中的前汛期异常旱年和异常涝年。分析前汛期同期(4~6月)及前期(前冬12月~当年2月)的500 hPa高度场资料和太平洋海温距平资料,发现肇庆前汛期异常旱、涝年的同期和前期500 hPa环流距平合成场,以及太平洋海温距平合成场分布的主要差异,为肇庆地区前汛期异常旱、涝的预测提供判别依据。     

江淮流域夏季旱涝与不同时间尺度大气扰动的关系

从不同时间尺度大气环流异常角度研究了江淮流域的汛期多雨和少雨情况,结果表明准定常行星波的异常对江淮流域旱涝有较为明显的影响;大气低频系统（准双周和季节内振荡）也有相当重要的作用,且以对流层高层（200 hPa）的准双周振荡和对流层低层（850 hPa）的季节内振荡的影响更为清楚;天气尺度扰动对汛期降水量异常的影响相对较小。低层准定常西南气流的强度与位置对旱涝的影响很大,若准定常西南气流强且偏向大陆,易造成江淮流域偏涝;若准定常西南气流弱或偏向大陆以东的洋面上,则江淮流域易旱。     

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;