2011年5月11-12日广西区域性暴雨诊断分析

利用NCEP1°×1°再分析资料、常规观测资料、自动站雨量资料、卫星TBB资料和雷达资料.对2011年5月11-12日广西出现的区域性暴雨进行诊断分析.结果表明:暴雨是在欧亚中高纬地区为两脊一槽的环流背景下产生的.500hPa南支槽、850hPa低涡和地面辐合线是其主要影响系统.水汽从南海输送到广西上空.并在桂西北产生强烈辐合.暴雨发生前广西处于θse高能舌区内,低层暖平流、中高层冷平流加剧大气层结的不稳定.在500hPa南支槽前正涡度平流输送下,桂西北850hPa低涡得到加强,低层辐合、高层辐散的垂直结构,有利于产生强烈的垂直上升运动.强降水与桂西北两个MBCS云团的强烈发展有关,冷云顶在-52℃以下的TBB低值区与暴雨落区有较好的对应关系.涡旋状降水回波的不断新生东北移是导致区域性暴雨发生的原因之一.     

2008年"7·12"广西区域性暴雨天气过程综合分析

对2008年7月12日广西全区性暴雨天气过程成因进行了综合分析,分析表明:500hPa低压环流、850百帕低空切变线和低涡是此次过程的天气尺度系统、中尺度系统是造成暴雨的直接原因。     

2008年台山市"龙舟水"特大暴雨过程分析

从500hPa环流、850hPa环流、地面形势、卫星云图与雷达资料、地形的屏障作用等方面,分析2008年台山市"龙舟水"的特大暴雨过程,试图为今后作"龙舟水"暴雨预报提供参考.     

2011年春季河南久旱转暴雨的环流特征及成因分析

利用常规气象资料和NCEP再分析资料,从前期天气背景、大气环流演变及产生持续性强降水的动力、热力和水汽等条件,分析了2008年6月广西出现的一次持续性强降水过程。结果发现：这次持续性强降雨过程期间500hPa环流形势稳定,高空西风小槽呈阶梯状持续下滑影响广西,不断诱发暴雨出现;200hPa广西处于南亚高压东部脊区和高空西风急流出口区右方,风速辐散明显,在高低空急流耦合作用下,华南出现了正反两支垂直环流,广西上空辐合上升运动明显,为强降水的出现提供极好的动力条件;南海季风暴发和副热带高压在华南沿海的稳定维持,使得华南低空形成了印度洋和南海两支水汽通道,为暴雨区上空提供了源源不断的水汽;高温、高湿、高能的热力条件,有利于扰动的形成和对流不稳定能量产生,为广西持续性暴雨提供必要的能量条件。     

开封市短期区域性暴雨分型预报方法

使用1965～1995年开封市历史气象资料，对其中36个区域性暴雨样本进行了分析。以此为基础，依据区域性暴雨日前24h高空(500hPa、700hPa、850hPa)环流形势，将开封市区域性暴雨划分为四型七类。以西风槽型和冷式切变线类区域性暴雨为例，给出了其入型指标和预报指标，并建立了开封市短期区域性暴雨预报模式。     

2008年中国-东盟博览会期间广西暴雨过程分析

利用常规资料、T639分析资料、Fy2C卫星云图资料对2008年中国-东盟博览会期间(10月22～23日)发生的一场区域性暴雨过程进行了综合诊断分析.结果表明:暴雨过程是由于西太平洋副高强,贝加尔湖低涡深,切变线南下增强及江南锋生共同影响造成.这些大尺度环流系统在广西北部表现为一向南向东倾斜的斜压系统,是此次初秋暴雨发生的环流背景.虽然没有大范围的低空急流水汽输送带,但稳定少变的副高边缘及南下增强的低空切变线仍在广西北部形成了高水汽环境和一定的对流不稳定能量,触发了中尺度对流系统活动,从而导致了暴雨过程的发生.     

广西一次持续性强降雨过程成因分析

利用常规气象资料和NCEP再分析资料,从前期天气背景、大气环流演变及产生持续性强降雨的动力、热力和水汽等条件,分析了2008年6月广西出现的一次持续性强降雨过程。结果发现：这次持续性强降雨过程期间,500hPa环流形势稳定,高空西风小槽呈阶梯状持续下滑影响广西,不断诱发暴雨出现;200hPa广西处于南亚高压东部脊区和高空西风急流出口区右方,风速辐散明显,在高低空急流耦合作用下,华南出现了正反两支垂直环流,广西上空辐合上升运动明显,为强降雨的出现提供了极好的动力条件;南海季风暴发和副热带高压在华南沿海的稳定维持,使得华南低空形成了印度洋和南海两吏水汽通道,为暴雨区上空提供了源源不断的水汽;高温、高湿、高能的热力条件,有利于扰动的形成和对流不稳定能量产生,为广西持续性暴雨提供了必要的能量条件。     

2008年6月广西持续性暴雨的诊断与数值模拟

用NCEP/NCAR全球逐日再分析格点资料和广西区域日降水资料,对2008年6月12—13日发生在广西的持续性暴雨过程进行了诊断分析,并利用中尺度数值模式WRF进行了数值模拟研究。结果表明:暴雨过程的水汽来源主要为孟加拉湾南部和南海北部;在强降水期间,暴雨区上空低层为较强的大气层结不稳定区,中高层为大气层结相对稳定区,不稳定能量与降水强度有着很好的对应关系;西南急流作为对流系统上升的触发机制,为广西持续性暴雨过程的发生和发展提供了水汽条件和动力条件。WRF模式成功模拟出本次暴雨过程的大尺度环流形势的演变及中尺度降雨分布,本次暴雨与850hPa上一个β中尺度低涡的生成和强烈发展直接关联。     

08．6广西连续暴雨的大尺度环流和物理条件分析

利用常规观测资料、自动站资料和每6h一次的NCEP1×1分析资料,对2008年6月8日。18日广西连续暴雨过程的大尺度环流和物理条件进行了分析。结果表明：副热带高空急流右侧维持强辐散场,500hPa中、低纬广西维持低压槽区,中、高纬东亚大槽和其后部阻塞高压形势维持,贝加尔湖以西宽广的槽区不断有小槽分裂东移,低空西南急流...     

兴安县"06.13"暴雨过程分析

[HT5"SS]利用常规气象资料、卫星云图、雷达产品等资料,从大气环流特征、物理量场、K指数、沙氏指数及降水云团的发展演变等方面对2007年6月13日兴安县的暴雨过程进行分析.结果表明:这次过程.500hPa高原槽加深东移影响本地;700hPa西南低空急流带来强盛的水汽辐合;850hPa低涡切变在兴安站附近生成并维持,同时地面相应位置有静止锋维持.同时有低压倒槽影响.高、中、低空环流形势的良好配合.是6月13日兴安站暴雨产生的真正原因.     

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.     

VARIABILITY OF INTER-ANNUAL RELATIONSHIP BETWEEN INDIAN OCEAN DIPOLE AND HUAXI REGION’S AUTUMN PRECIPITATION

The moving-window correlation analysis was applied to investigate the relationship between autumn Indian Ocean Dipole (IOD) events and the synchronous autumn precipitation in Huaxi region, based on the daily precipitation, sea surface temperature (SST) and atmospheric circulation data from 1960 to 2012. The correlation curves of IOD and the early modulation of Huaxi region’s autumn precipitation indicated a mutational site appeared in the 1970s. During 1960 to 1979, when the IOD was in positive phase in autumn, the circulations changed from a “W” shape to an ”M” shape at 500 hPa in Asia middle-high latitude region. Cold flux got into the Sichuan province with Northwest flow, the positive anomaly of the water vapor flux transported from Western Pacific to Huaxi region strengthened, caused precipitation increase in east Huaxi region. During 1980 to 1999, when the IOD in autumn was positive phase, the atmospheric circulation presented a “W” shape at 500 hPa, the positive anomaly of the water vapor flux transported from Bay of Bengal to Huaxi region strengthened, caused precipitation ascend in west Huaxi region. In summary, the Indian Ocean changed from cold phase to warm phase since the 1970s, caused the instability of the inter-annual relationship between the IOD and the autumn rainfall in Huaxi 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.     

全球贸易隐含碳变化及其影响分析

基于最新的GTAP8 (Global Trade Analysis Project）数据库,使用投入产出法,分析了2004年到2007年全球贸易变化下南北集团贸易隐含碳变化及对全球碳排放的影响。结果显示,随着发展中国家进出口规模扩张,全球贸易隐含碳流向的重心逐渐向发展中国家转移。2004年到2007年,发达国家高端设备制造业和服务业出口以及发展中国家资源、能源密集型行业及中低端制造业出口的趋势加强,该过程的生产转移导致全球碳排放增长4.15亿t,占研究时段全球贸易隐含碳增量的63%。未来发展中国家的出口隐含碳比重还将进一步提高。贸易变化带来的南北集团隐含碳流动变化对全球应对气候变化行动的影响日益突出,发达国家对此负有重要责任。     

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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