桂林10月暴雨的分析和预报

利用历史天气图资料，统计1960—2002年共42a桂林市10月暴雨天气过程，分析其影响天气系统环流特征及演变规律，分类建立预报模式指标，为10月暴雨实时预报业务提供一些参考。     

2019年陕西汛期暴雨预报检验评估

基于陕西省气象台(下简称省台)主观订正预报产品、ECMWF细网格预报产品和模式动态交叉取优要素预报方法(DCOEF)预报产品,对2019年4-10月陕西省暴雨天气过程进行检验评估。结果表明,省台主观订正预报产品对晴雨、小雨、暴雨、一般性降水、暴雨以上降水均有较好的预报效果,ECMWF细网格预报对中雨、大雨预报较好,评分较高;三种产品对区域性暴雨的预报能力均强于对局地性暴雨的预报能力,省台主观订正预报产品和DCOEF预报产品评分优于ECMWF细网格预报产品。     

广西非汛期暴雨事件的特征分析

通过对 196 3- 1999年间广西非汛期 (10月至次年 3月 )暴雨天气过程这一异常天气事件的时间分布及其主要影响系统的分析得出 :广西非汛期异常暴雨天气事件的发生是中、低纬天气系统相互作用在广西地区的反映。关注这一特征 ,对提高广西非汛期异常暴雨天气的预报水平具有参考作用。     

驻马店秋季暴雨成因及预报

利用驻马店1991～2001年9～10月历史降水资料、天气图资料及数值预报产品,分析了产生秋季暴雨天气的环流形势和影响系统,选取了预报因子,建立了预报方程.     

2019年陕西汛期暴雨预报检验评估

基于陕西省气象台(下简称省台)主观订正预报产品、ECMWF细网格预报产品和模式动态交叉取优要素预报方法(DCOEF)预报产品,对2019年4—10月陕西省暴雨天气过程进行检验评估。结果表明,省台主观订正预报产品对晴雨、小雨、暴雨、一般性降水、暴雨以上降水均有较好的预报效果,ECMWF细网格预报对中雨、大雨预报较好,评分较高;三种产品对区域性暴雨的预报能力均强于对局地性暴雨的预报能力,省台主观订正预报产品和DCOEF预报产品评分优于ECMWF细网格预报产品。     

江西省汛期暴雨气候特点及预报方法综合分析

概括介绍了江西省汛期暴雨的气候特点、汛期暴雨环流形势和天气系统特征,以及针对江西省汛期暴雨的预报方法研究进展。最后,提出了未来一段时间江西省暴雨预报方法研究的主要方向,认为应该将暴雨过程的天气尺度和中尺度特征与地形特征相结合,开发暴雨预报方法并建立暴雨预报模式。     

广西非汛期暴雨事件的特征分析

通过对1963－1999年间广西非汛期（10月至次年3月）暴雨天气过程这一异常天气事件的时间分布及其主要影响系统的分析得出：广西非汛期异常暴雨天气事件的发生是中、低纬天气系统相互作用在广西地区的反映。关注这一特征，对提高广西非汛期异常暴雨天气的预报水平具有参考作用。     

环流分型在万州暴雨预报方法中的应用

通过对万州区龙宝气象站1980～2005年188个暴雨个例资料的分析,将产生暴雨的天气形势划分为若干环流型,主要着眼于影响暴雨的物理量,筛选出预报指标和预报因子,使用统计预报方法,根据天气环流形势的分型,分别组建了5、6、7、8、9月及4月和10月的各月份每种环流型未来36小时万州区大到暴雨以上各暴雨量级预报方程.预报检验表明该预报方法是可信的,同时也表明客观划分环流型、筛选预报因子、恰当确定各暴雨量级与预报因子标准等级是预报方法的关键.     

驻马店秋季暴雨成因及预报

利用驻马店1991～2001年9～10月历史降水资料、天气图资料及数值预报产品，分析了产生秋季暴雨天气的环流形势和影响系统，选取了预报因子，建立了预报方程。     

1994年汛期暴雨数值预报分析

本文着重分析了１９９４年汛期５次暴雨天气过程的雨量数值预报结果，简要阐述了产生暴雨天气的天气背影并把该数值预报结果与日本人的同类数值预报结果进行了比较，发现本系统对暴雨折预报结果明显优于日本的数值预报结果，从结果的分析可以看到，本系统无论是对暴雨范围的预报，还是对暴雨雨量的预报，都是非常令人鼓舞的。     

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.     

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.     

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.     

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.     

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. Contributions from all over the world are welcome.SUBMISSIONAll submitted     

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.