飞机增雨天气实时监测资料的显示

为满足飞机增雨作业实时性的需要，方便快捷地分析各种监测资料，建立了集省域常规天气报告、卫星云图、雷达图像、航危天气报告于一体的飞机增雨天气资料显示分析软件，实现了网上GMS-5云图的实时监测、动画、云层作业条件分析等，业务应用取得了较好的效果。     

锡林郭勒盟一次飞机增雨作业天气条件分析

文章利用天气分析、探空资料、卫星云图和人工影响天气数值预报产品对2015年5月10—11日降水天气形势、飞机增雨作业条件和增雨效果进行分析,结果表明:(1)此次天气过程影响系统为蒙古低涡,充沛的西南水汽输送和辐合条件有利于产生降水,系统移动慢,影响范围大,降水持续时间长。(2)雨水含量高值区主要集中在3000～8000m,-4～-6℃的湿层出现在850～600hPa之间,湿层较厚,水汽含量高,层结稳定,飞机增雨作业条件理想。(3)利用人工影响天气数值预报产品准确预报降水性质、影响范围和降水时段,合理设计飞机增雨作业方案,有效提高了增雨效果。     

适合飞机人工增雨作业天气系统的雷达回波特征分析

应用2004～2005年沈阳辉山新一代天气雷达资料和常规气象资料,对实施飞机人工增雨作业的天气系统、增雨作业云系及其雷达回波特征进行了归纳和分析,并提出了飞机人工增雨作业条件和作业时机、作业区域等判别方法,为实施飞机人工增雨作业提供科学依据。     

一次增雨作业的FY-4A卫星反演分析

本文利用FY-4A卫星对2019年5月四川盆地实施的一次人工增雨减轻空气污染作业条件进行分析，综合分析增雨可播性，判别增雨潜力区和作业高度，为开展人工增雨作业提供可靠的依据，然后利用多普勒天气雷达、地面气象台站、空气质量指数、颗粒物污染物浓度等多种数据资料分析人工增雨作业前后作业云体宏观情况和空气质量、雨量的变化，对其作业效果进行分析。结果表明:(1)5月12日四川盆地西部有云系发展，作业前6小时作业区附近主要为积层混合云，存在大量过冷水，红色对流泡云顶温度约为-30℃，粒子有效半径为15～40μm，作业前0～3小时作业区位于深厚对流降水云边缘，云顶温度约为-40℃，粒子有效半径为7～40μm，作业区南部有大片积层混合云，提供大量过冷水；(2)作业区内，高低空配合的环流场形成了较有利的降水形势，作业云体过冷水丰沛，增雨潜力较好，符合人工播撒催化剂条件，适宜开展人工增雨作业；(3)经过人工增雨作业后，作业区雨量峰值降雨时间延长，总体雨量增加，作业区的AQI从82降到29，PM₁₀从94μg/m3下降到28μg/m3，PM_2.5从49μg/m3降到17μg/m3，而3个对比区没有实施人工增雨作业，空气质量指数持续超标数小时。      

锡林郭勒盟2020年6月21—22日飞机人工增雨作业个例分析

文章利用常规观测资料、NCEP再分析资料、自动气象站观测资料和锡林浩特多普勒天气雷达产品等分析了2020年6月21—22日锡林郭勒盟一次明显降雨天气过程,以及飞机人工增雨作业效果。结果表明:(1)在天气形势和作业条件适宜的情况下,对系统云系播撒催化剂,促使大量的人工冰核迅速形成冰晶,使云中过冷水转化为降水。(2)飞机人工增雨作业后,作业区及下风方向的降水回波强度稳定或加强,回波面积明显扩大。(3)自动气象站雨量观测资料分析得出,飞机人工增雨作业使得飞机作业区及下风方向区域的降水范围及降水量均增大,增雨效果能维持3～6 h。(4)在有利的天气背景下,K指数为22～28℃,SI指数为0～2℃,比湿为8～12 k·kg-1,云顶温度在-15～-50℃,飞机人工增雨作业时间段内,云体较厚,含有丰富的过冷水,这种低能量高湿度且有较厚云体,具备了好的增雨潜势,适于开展飞机人工增雨催化作业。     

用GMS资料建立飞机增雨宏观作业模型

根据飞机人工增雨作业的特点，利用卫星资料接收系统获取的GMS卫星11原始资料，讨论了适宜飞机增雨作业应用的卫星数据定位、红外数据重采样等小区域GMS资料处理方法。利用影响山东省12次降雨天气过程的GMS-5卫星资料与其对应时次的94个雨量观测站自记降雨资料，统计分析了静止气象卫星多通道资料与降雨概率、降雨强度的关系，初步建立了云层可作业几率、期望增雨量等宏观作业模型。     

2014年山东首场透雨人影服务和作业条件监测分析

2014年春季山东遭遇了较为严重的旱情。针对4月25—27日全省性降水天气过程,山东各级人影部门积极开展人工增雨作业。文中详细地介绍了利用天气实况、卫星、雷达等实时观测资料和多家数值预报资料开展对增雨作业条件的提前预报分析、作业时机和作业部位的临近监测识别以及山东省人工影响天气办公室组织开展的飞机人工增雨作业服务情况,为开展飞机增雨作业积累经验。     

新一代天气雷达产品在人工增雨作业中的应用

将新一代天气雷达产品和常规天气分析结合起来对 2 0 0 2年 5月 1 0日闽西武平县人工增雨作业条件和效果进行综合分析。结果表明 :(1 )将新一代天气雷达的众多产品结合常规天气分析 ,可提高人工增雨作业和效果评价的科学性、准确性 ;(2 )人工增雨作业取得明显效果 ,增雨 1 1× 1 0 8m3。     

一次飞机增雨作业的云参数变化响应分析

本文利用FY－2C静止卫星资料,以2013年5月8日四川盆地一次飞机增雨作业为例,反演了云顶温度、云顶高度、云粒子有效半径、液水路径、云光学厚度等云物理量参数,结合自动气象站资料和探空资料等,对此次飞机增雨效果进行了物理检验。结果表明:作业前,云顶温度－13℃,云粒子有效半径10μm,云体较厚,含有丰富的过冷水,具有较好增雨潜力;作业后,作业区云层增厚,云顶温度降低,云粒子有效半径增加至25μm,云顶冰晶化,冰水转化过程加快,产生了较多的降水,降水量增幅明显;作业后,对比区降水不充分,各云物理参数无明显变化。      

基于CA-FCM方法的飞机增雨效果检验及分析

采用河南省2013—2017年飞机增雨作业资料,利用CA-FCM方法进行增雨效果检验,以探究CA-FCM方法在河南区域飞机增雨效果检验中的合理性及适用性,并分析相对增雨率与季节、检验物理量、垂直积分液态含水量之间的关系。结果表明：CA-FCM方法应用于河南省飞机增雨效果检验,能够获得定量而合理的增雨效果。多数作业相对增雨率0%—40%,少数作业存在减雨效果。研究中春季、夏季、秋季相对增雨率分别为20.8%、22.4%、-22.6%。春季、夏季飞机增雨效果明显优于秋季,一半的秋季增雨作业呈减雨效果,这可能与作业云层可播性条件有较大关系,春季、夏季云层可播性条件优于秋季。显著性检验表明,65%的作业增雨效果显著。增雨作业区域的垂直积分液态含水量越大,相对增雨率显著增加。具有“作业前回波30—50 dBz”、“作业云层尺度较大”条件的作业,易产生一定增雨效果;作业云层回波20—30 dBz,易产生减雨效果;回波强度及面积的维持或增强对增雨效果有明显贡献。     

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;