一次南支槽引发德宏州强对流天气成因分析

利用常规气象观测资料、静止气象卫星云图资料和多普勒雷达探测资料,对2013年5月3日一次南支槽引发云南德宏州发生雷暴大风和冰雹强对流天气过程的特征、中尺度环境场及成因进行了分析,结果表明:5月3日在南支槽天气背景下德宏区域内为对流不稳定,具上干下湿的不稳定层结,有强的垂直风切变;在干线和中尺度辐合线的触发下产生了这次强天气过程。高分辨率卫星云图能够清楚的监测MCS的发生发展,雷达监测提高了时空分辨率,监测到速度模糊、弓形回波、三体散射、后侧"V"型缺口、有界弱回波区等指示冰雹、大风等强对流天气的雷达回波特征。     

一次降雹过程的数字化雷达回波分析

利用东营市７１３数字化雷达和卫星云图资料，分析了１９９５年６月２４日发生在黄河三角洲地区的暴雹天气过程，对冰雹云的雷达回波特征及卫星云图特征进行了分析。     

一次降雹天气过程的数字化雷达回波分析

主要利用东营市７１３数字化雷达回波和红外卫星云图资料，分析了１９９６年７月２０日东营地区降雹天气过程的雷达回波和卫星云图演变特征。结果表明：雷达回波具有明显的雹云回波的特殊形状和跃增阶段，跃增是冰雹云与雷雨云回波的一个显著差别。     

绥化市2009年7月8日冰雹天气分析

本文利用Micaps2.0常规天气资料、FY-2红外卫星云图、数值预报产品以及雷达回波资料进行分析,从大尺度环流特征、雷达回波特征等方面入手,对2009年7月8日绥化地区发生的区域性冰雹天气进行天气学诊断分析,找出区域性冰雹的预报着眼点,以提高冰雹天气的预报水平。     

陕西初夏冰雹天气气候特征及预报

根据我省多年冰雹预报工作研究成果，归纳出我省初夏冰雹天气气候规律，有利冰雹形成的天气形势和物理量、卫星云图、雷达回波特征，为我省初夏冰雹天气预报提供依据。     

岑溪8．23大暴雨剖析

2004年8月23日17时48分～19时48分，岑溪市出现了一次特大暴雨降水过程，这次强降水的特点是降水的时间短、强度强。通过对影响这次强降水的天气系统、卫星云图和雷达回波进行分析，找出产生大暴雨过程的一些特征。     

一次冰雹天气过程的潜势条件和中尺度特征分析

基于常规观测资料、NCEP(1°×1°)再分析资料、FY-2G卫星云图和多普勒雷达资料等对2018年6月10日发生在甘肃省平凉市的冰雹天气过程进行分析,得出以下结论:(1)此次冰雹过程属于典型的西北气流型,高空强冷平流、冰雹发生区明显的切变线和地面辐合线以及高层气流引导地面辐合线附近生成的中尺度对流系统MCS,是造成此次强天气的主要影响系统。(2)中尺度辐合线和干线为此次冰雹天气提供了较好的触发机制;强冰雹发生区螺旋度的异常增大为雹暴系统的发展增强提供了强有力的环境场条件;强垂直风切变可促使不稳定能量释放,形成冰雹等天气,和湿斜压作用共同形成MCS发生发展的有利条件;冰雹发生区0℃层、-20℃层高度及二者之间的厚度均有利于大冰雹的形成。(3)多普勒雷达资料显示,引发强天气的回波单体附近,悬垂回波、弱回波区、钩状回波等特征明显,对应径向速度图有明显的中气旋、中层径向辐合及风暴顶辐散等特征配合,对此次冰雹等天气有很好的指示作用。     

2011-06-11豫北强对流天气过程分析

利用常规观测资料、加密地面资料、卫星云图和多普勒雷达回波等资料,从天气形势、物理量场和回波演变特征等方面对2011年6月11日午后发生在豫北地区的强对流天气进行分析发现:高空冷平流和24 h显著降温区叠加在低层暖区之上,形成上干冷下暖湿的位势不稳定层结,为强对流的产生提供了层结条件;地面暖低压发展和辐合中心、辐合线是这次强对流天气的触发机制;0-6 km较大的垂直风切变有利于强对流天气的发展和维持。卫星云图和雷达产品显示:对流云团的发展和移动与地面切变线、雷达回波一致,并可预测强天气落区。当回波中心强度≥50 d Bz、回波顶高≥12 km、垂直累积液态含水量≥45 kg/m2时,极易造成短时强降水和冰雹天气。三体散射特征和中气旋的出现对确定发布冰雹预警有指示意义,17:50第一次观测到三体散射特征发布冰雹预警,时效在20~90 min。垂直液态含水量在强降水发生前20 min开始剧增,为判别短时强降水等强对流天气提供有效依据。     

准葛尔盆地南缘春季一次强冰雹天气的综合分析

利用常规气象探测资料和多普勒天气雷达产品,结合石河子地区和兵团农六师的高密度自动站网资料,对2010年5月2日在准葛尔盆地南缘发生的-强冰雹天气过程,从天气形势、云图、物理量场和雷达回波演变特征等几个方面进行了综合分析.结果表明:这次冰雹天气出现在对流不稳定层结条件下,中高层干冷、低层暖湿,水汽条件充沛,0℃层和-20...     

一次冰雹过程的卫星云图和雷达回波特征分析

应用常规资料、FY-2C红外云图和河南省三门峡市的多普勒雷达产品。对陕西中北部的一次强对流性天气过程进行分析,结果表明：影响系统是高空下滑冷槽、中低层暖平流和地面弱冷锋。上干冷、下湿暖的对流性不稳定层结为冰雹天气的形成提供了有利条件。卫星云图上,锋面前部形成的两个中-β尺度系统受锋面附近前冲冷流的触发,造成这次强对流性天气。雷达反射率图上,回波强度越大、强中心高度越高,造成的天气越强;径向速度图上的“逆风区”,说明该地为风速的大值区、风向也发生了突变;当对流回波处于强盛阶段时,VIL值先猛增、后相对稳定,当达到峰值时即出现冰雹,当突然减小时,影响地面将出现大风．因此VIL对冰雹和大风的判别有很好的预报意义。     

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.     

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.     

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     

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。     

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.     

Retrieval of outgoing longwave radiation from COMS narrowband infrared imagery

Hourly outgoing longwave radiation(OLR) from the geostationary satellite Communication Oceanography Meteorological Satellite(COMS) has been retrieved since June 2010. The COMS OLR retrieval algorithms are based on regression analyses of radiative transfer simulations for spectral functions of COMS infrared channels. This study documents the accuracies of OLRs for future climate applications by making an intercomparison of four OLRs from one single-channel algorithm(OLR12.0using the 12.0 μm channel) and three multiple-channel algorithms(OLR10.8+12.0using the 10.8 and 12.0 μm channels; OLR6.7+10.8using the 6.7 and 10.8 μm channels; and OLR All using the 6.7, 10.8, and 12.0 μm channels). The COMS OLRs from these algorithms were validated with direct measurements of OLR from a broadband radiometer of the Clouds and Earth's Radiant Energy System(CERES) over the full COMS field of view [roughly(50°S–50°N, 70°–170°E)] during April 2011.Validation results show that the root-mean-square errors of COMS OLRs are 5–7 W m-2, which indicates good agreement with CERES OLR over the vast domain. OLR6.7+10.8and OLR All have much smaller errors(～ 6 W m-2) than OLR12.0and OLR10.8+12.0(～ 8 W m-2). Moreover, the small errors of OLR6.7+10.8and OLR All are systematic and can be readily reduced through additional mean bias correction and/or radiance calibration. These results indicate a noteworthy role of the6.7 μm water vapor absorption channel in improving the accuracy of the OLRs. The dependence of the accuracy of COMS OLRs on various surface, atmospheric, and observational conditions is also discussed.