上海青浦CINRAD/SAD雷达和南汇WSR-88D雷达数据对比分析

上海青浦CINRAD/SAD雷达和南汇WSR 88D雷达型号不同,并且采用不同的双偏振技术升级方案,实际业务运行中2部雷达存在一定的数据偏差。为了对雷达的探测性能进行定量评估,在共同探测区域遴选2022年7—9月及2023年6月共30个过程3933个时次数据,以稳定性降水与对流性降水分类并按强度分级进行对比,评估了反射率因子ZH,差分反射率ZDR,相关系数CC和差分传播相移ΦDP的水平分布特征及随方位变化趋势,雷达灵敏度随仰角变化趋势以及ZH和ZDR偏差的定量统计。结果表明：2部雷达ZH的观测结果接近,青浦CINRAD/SAD雷达的ZH,CC和ΦDP受地物及避雷针影响较大,随方位变化不稳定,青浦CINRAD/SAD雷达在低层的非气象回波滤除效果较南汇WSR 88D雷达差。2部雷达ZH和ZDR的偏差在ZH大于40 dBz的区域较大,ZH平均偏差为0.9 dB,ZDR为-0.14 dB。本文基于台风、冰雹、短时强降水和梅雨降水数据,定量化评估了上海2部S波段双偏振天气雷达数据之间的差异,为后续算法改进以及数据订正提供参考。     

ASOM平台新一代天气雷达故障规范填报

综合气象观测系统运行监控平台（ASOM）是气象技术装备保障的业务应用系统。系统实现了气象探测设备的运行状态监控、探测数据质量监控、维护维修信息管理、装备保障信息管理、运行监控综合评估、监控信息发布和站网信息管理等功能。利用ASOM系统中2008年7月至2014年7月的4000余条故障维修填报记录,围绕故障修复流程进行分析,探讨新一代天气雷达故障维修信息的规范填报并给出建议。文章旨在围绕雷达系统故障维修信息的规范填报,还原故障维修过程,改进故障诊断技术,达到提高台站雷达维修水平目的。     

基于S波段双偏振雷达一次强雹暴过程观测分析

利用宁波S波段双偏振天气雷达资料、NCEP再分析资料、结合常规观测资料和实地冰雹调查资料，对2020年3月21日浙江省中北部一次强雹暴灾害过程（简称“03〖DK〗·21”过程）的天气背景和双偏振雷达回波演变特征进行分析。结果表明：〖JP2〗①此次雹暴过程环流形势属于低层暖平流强迫类型，雹暴影响过程约4 h，雹暴A和B先以强的对流单体形态移动，在自西向东移动过程中分别加强为超级单体。②典型降雹时次具有明显的三体散射特征（TBSS），〖JP〗垂直剖面图上强回波（＞50 dBz）伸展高度超过-20 ℃层，低层的弱回波，中高层悬垂回波明显。径向速度垂直剖面图上，雹暴低层辐合，其上叠加了辐散层，使得雹块得以继续形成和增长。③冰雹区出现了ZDR冰雹信号，对应的反射率因子（ZH）均大于65 dBz，差分反射率因子（ZDR）介于-2.0~0 dB，相关系数（CC）介于0.80～0.98；当结合ZH、ZDR、CC综合判断云中有冰雹粒子，CC<0.9时KDP的“空洞”区域也可作为判别大冰雹的依据之一。④HCL产品较好地反映了空中冰雹的分布和演变，根据低仰角的冰雹色标、同时结合零度层高度和雹云团下温度递减率值的大小，能更好地判断出冰雹发生的落区和尺寸。     

ZDR柱识别方法在海南地区的应用

基于双偏振天气雷达的相关研究大部分集中在雷达如何识别粒子相态、精细化探测云系垂直结构方面，专门针对差分反射率因子ZDR柱的识别研究相对较少。通过对海南地区对流云系特征进行分析研究，提出一套基于双偏振雷达探测数据（2020—2021年）的ZDR柱识别方法，结合多源资料对发生在海南地区的2次对流天气过程展开分析，〖JP2〗验证ZDR柱识别效果。结果表明：①ZDR柱通常在对流云系前中期较为深厚，最大可达0 ℃层以上3～5 km，〖JP〗在空间分布上ZDR柱与雷达径向速度的辐合有密切关系，其正负径向速度对的差值与ZDR柱的强弱变化规律呈正相关，并且深厚的ZDR柱较大概率出现在对流云系运动方向的前缘位置，与对流云团雷达反射率因子较大区域（≥50 dBz）有明显的对应关系；②ZDR柱最大深度的变化趋势同雷达回波顶高和垂直累计液态水含量有弱相关性，雷达回波顶高和垂直累计液态水含量的变化通常滞后于ZDR柱深度的变化（约12～15 min）。该方法具备识别海南岛地区ZDR柱现象的能力，可以在分析强对流天气过程、人工影响天气指挥和短临灾害天气预警等方面发挥应用效益。     

雷击风险评估中损害概率PB和PSPD参数的计算分析

通过对雷击建筑物所造成建筑物及其内部系统损害原因的分析,结合《雷电防护》GB/T21714系列标准,分析得知GB/T21714.2中损害概率PB和PSPD与雷电流的概率分布和LPL（Lighfning Pretection Level,雷电防护水平）对应的雷电流极值有关。PB的数值等于雷电流大于LPL对应雷电流最大值的概率,与其小于雷电流最小值的概率之和;PSPD的数值等于雷电流大于LPL对应雷电流最大值的概率。同时指出,《建筑物防雷设计规范》GB50057－2010中各个LPL的损害概率PB和PSPD不应直接采用GB/T21714.2中的规定值,应根据GB50057给出的雷电流参数进行计算,或利用雷电监测网的资料,获取建筑物附近一定范围内的云地闪数据,统计得到雷电流概率分布函数,依据该雷电流概率分布函数来计算PB和PSPD。     

一次强降水超级单体风暴双偏振参量特征分析

利用青岛双偏振多普勒天气雷达资料和探空及自动气象站观测资料，对2020年8月3日发生在山东高密的一次强降水超级单体风暴双偏振特征进行了分析。结果表明：①强的对流有效位能（CAPE）、低层强垂直风切变、高空强辐散及高湿是强降水风暴发展维持的关键环境因素。②风暴低层存在差分反射率因子ZDR弧和差分相移率KDP高值区，ZDR弧与入流缺口一侧反射率因子梯度高值区相匹配，对应偏小的KDP和相关系数，〖JP2〗以少量大粒子为主；KDP高值区为强降雨区，对应小于3 dB的ZDR和大的相关系数，以高浓度、大小适中的液态粒子为主。③有界弱回波区BWER外围存在ZDR环，对应偏小的KDP，而BWER上方存在深厚宽阔的ZDR柱和KDP柱，KDP柱高于ZDR柱的高度，气旋性旋转上升气流区内中层以下分布有少量大的粒子，而中层之上分布有较高浓度的大粒子。④-20 ℃层高度之下含有丰富的液态粒子，-20 ℃层高度之上含有丰富的霰粒子和冰晶粒子，是高密强降水超级单体风暴典型的微物理垂直结构特征。〖JP〗     

大别山区茶叶气候生产潜力评估

基于大别山区35个气象观测站1971—2020年逐日气象资料、DEM数据，采用气候统计分析、逐步订正法和趋势面插值等方法，对茶叶光合生产潜力（YQ）、光温生产潜力（YT）和气候生产潜力（YW）时空变化特征、气候资源贡献率及其对气候变化的响应进行了分析。结果表明：大别山区茶叶YQ和YW呈下降趋势，降幅分别为0.58和0.05 t〖DK〗·hm-2〖DK〗·(10a)-1，YT呈增加趋势，增幅为0.36 t〖DK〗·hm-2〖DK〗·(10a)-1；空间分布上，YQ随纬度的增加而增加，YT随纬度和海拔的增加而减少，YW随纬度的增加而减少、随海拔的增加而增加；太阳辐射、温度和降水对YW的贡献率分别为26%、48%、26%，温度的促进作用与太阳辐射和降水的抑制作用相互抵消，致使YW总体呈动态平衡趋势；气候变化背景下，大别山区北部地区较南部地区YQ下降趋势更加明显，南部地区较北部地区YT增加趋势更加明显，YW在低海拔地区呈增加趋势而在高海拔地区呈下降趋势。研究结果可为大别山区茶叶产业充分利用气候资源、高效趋利避害、合理优化产业布局提供科学依据。     

一次强寒潮过程的多相态降水分析

综合利用常规观测资料、双偏振雷达和雨滴谱仪探测资料，对2020年3月28日发生在常州地区的一次罕见强寒潮引起的降雨、雨夹雪和雪不同相态降水天气进行了分析。结果表明：①此次3月末罕见强寒潮和降水主要是在高空槽、中低层切变线和西南急流与地面冷高压配合下，强冷平流入侵以及850 hPa明显干层的蒸发（或升华）吸热的共同作用引起的，中低层温度的急剧下降，导致降水相态发生变化。②双偏振雷达监测到3种降水相态呈现出不同的偏振变量特征：降雨相态向雨夹雪转变时，反射率因子Z增大，差分反射率因子ZDR增大，相关系数CC有明显的低值带状分布，呈现出Z>30 dBz，ZDR>1 dB，CC<0.95组成的雨雪相态混合区域；而纯雪则为Z>22 dBz，ZDR<1 dB，CC>0.98。③雨滴谱仪显示降雨阶段主要由高浓度小粒子构成，雨滴速度〖CD*2〗尺度谱呈现为倾斜的带状；雨夹雪阶段数浓度减小，粒径范围较宽，质量加权平均直径明显增大，雨滴速度〖CD*2〗粒径范围介于降雨和纯雪之间；纯雪阶段速度〖CD*2〗尺度谱下压右伸，粒子直径分布较宽。     

香港地区加权平均温度特征分析

利用香港Kings Park探空站(站号45004)2003—2009年探空资料回归了大气加权平均温度Tm、地面温度Ts、气压es和水汽压Ps的线性公式.通过比较分析发现Tm Ts单因素回归结果和Tm Ts、es、Ps多因素回归结果没有显著差异,但基于本地化探空数据的回归公式精度比Bevis公式高;增加样本数回归分析并不能显著提高公式精度,采用最近一月探空数据回归公式即可很好地由Ts拟合下年Tm,拟合均方根误差(F RMS)为1946 K;用2003年数据回归出的经验公式Tm=11329+05 863Ts去拟合2004—2009年的数据,拟合均方根误差〖JP2〗基本没有差异,因此某地Tm Ts经验公式一次回归可长期使用．通过对全国83个国际交换站2009年探空数据回归得出我国大陆地区最新Tm Ts经验公式为Tm=〖JP〗53244+0783Ts,该一般公式拟合均方根误差与本站数据回归剩余均方根误差(RRMS)相当,可代替本地公式广泛使用．     

鄂北一次超级对流单体的双偏振雷达特征分析

利用湖北省随州市S波段双偏振雷达资料及常规观测资料，对2020年5月4日鄂北随州出现的超级单体风暴进行分析。结果发现：①在有利天气背景作用下，形成了上干冷下暖湿的垂直层结、0~6 km中等强度垂直风切变以及地面辐合线，为强风暴的发生发展提供环境条件和触发条件。②超级单体发展过程中，观测到前侧“V”形入流缺口、中气旋、弱回波穹隆、悬垂回波、钩状回波等特征，且风暴顶高度、风暴质心高度、最大水平反射率因子高度以及垂直累积液态含水量等风暴参数均呈先升后降趋势。③超级单体的发展和成熟阶段，在0 ℃层以下的低层，于前侧下沉气流西侧的水平反射率因子大梯度区观测到浅薄的差分反射率因子Zdr大值区，即Zdr弧；④超级单体的初始阶段、发展阶段以及成熟阶段，在0 ℃层之上的中层，观测到强上升气流的正温度扰动使冰相粒子在附近融化而形成的Zdr环形大值区和相关系数环形小值区。⑤垂直方向上，在超级单体的初始阶段、发展阶段以及成熟阶段均观测到Zdr柱和差分相位常数Kdp柱。Zdr柱与弱回波穹隆区位置对应较好，其不同时期特征反映了上升气流强的变化；Kdp柱的变化反映了超级单体中含有大量液态水滴区域的变化。     

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.     

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     

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.     

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.     

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.     

Information for Authors

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.     

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.     

INFORMATION FOR AUTHORS

正Aims Scope Advances in Atmospheric Sciences(AAS)is an international journal on the dynamics,physics,and chemistry of the atmosphere and ocean with papers across the full range of the atmospheric sciences,co-published bimonthly by Science Press and Springer.The journal includes Articles,Note and Correspondence,and Letters.Contributions from all over the world are welcome.