利用多普勒雷达、风廓线雷达、FY-4A黑体亮温(TBB)、地基微波辐射计、地面自动站等多种观测资料以及ERA5再分析资料,对"利奇马"(2019)台前飑线的过程演变及其发生位置、移动方向和长生命史的异常特征进行分析,结果表明:(1)台前飑线过程经历了发展形成、加强成熟和减弱消亡三个阶段,其中第二阶段影响范围最广、强度最强,过境造成的气象要素变化具有极端性.地面中尺度雷暴高压、飑前热低压、冷池、暖中心特征明显.(2)台前飑线发生在增强的大陆高压与台风之间的湿区带上;台风为台前飑线过程提供了充沛水汽,强的不稳定环境产生大的对流有效位能(CAPE)和东北气流辐合;上干下湿的热力不稳定层结、低空强的垂直风切变是此次台前飑线生成的大气环境条件.(3)台前飑线进入福建后,大气层结不稳定持续显著增强、低空垂直风切变异常增强且时间长维持以及台前飑线与前缘激发生成的对流风暴合并促使台前飑线发展增强,是其生命史延长的重要原因.(4)东北气流增强引导台前飑线向西南方向移动,飑线与引导气流夹角大,二者移动方向一致,移速加快,有利地面大风增幅.(5)地基微波辐射计资料计算的热力对流参数(K、TT和A指数)的峰值与大风极值有着很好的对应关系,K≥37℃和A≥11℃指数对强对流天气预警有一定的参考价值.

利用福建省近十年2000多个自动站降水数据,详细分析了短时强降水的月变化、日变化及空间分布特征,分析不同标准下暴雨预警发布频次、发布极值.结果表明,近十年福建省短时强降水空间分布不均,整体上沿海比内陆频繁,极端短时强降水高发区位于沿海,且空间分布集中;短时强降水季节内分布不均匀,以6-8月最为频繁,极端短时强降水在8月活动最为频繁;短时强降水日变化呈现明显单峰结构,主峰出现傍晚;不同暴雨预警指标发布数量差异极大,通过细化预警发布规则,可为福建省暴雨预警信号标准修订及预警信号属地化业务改革提供借鉴和参考.

利用2017—2018年葵花卫星(Himawari)TBB亮温资料,计算最低亮温、亮温梯度、红外与水汽亮温差和低亮温区面积及其随时间变化率等特征参量,确定短时暴雨的卫星参数阈值,并融合了雷达参数阈值及过去1h地面加密降水实况资料,采用指标叠加法判定监测区域内某一云团未来2h能否产生区域性短时暴雨天气,并采用交叉相关法外推云团的移动,进而对强降水云团进行预警.对2019年几次暴雨过程预报检验结果是:预警命中率(POD)为80.6％～97.1％,平均为91.0％,临界成功指数(CSI)为77.2％～79.2％,平均为77.9％,所预警的云团未来2 h影响区域出现≥30 mm/h短时暴雨站数占全省短时暴雨站数的76.4％～96.2％,平均为85.2％,整体预警效果较好.

为研究风云四号A星闪电成像仪(FY-4A LMI)闪电资料在强对流天气的监测预警能力,以2019年台风"利奇马"台前飑线为例,利用FY-4A LMI闪电资料、FY-4A云顶亮温资料(TBB)、地基闪电定位资料(ADTD)、组网雷达组合反射率因子资料和东南沿海自动站风雨资料,研究"利奇马"台前飑线全闪电活动的时空分布特征及其与飑线内对流演变的关系.结果 表明:FY-4A LMI闪电频次的时空变化与台前飑线的演变过程相一致,LMI闪电爆发对台前飑线强度增强具有提早约1h的指示作用.在闪电活动与台前飑线对流的演变关系上,LMI闪电与卫星TBB深对流及雷达强回波的时空演变存在较好的相关性.LMI观测的闪电频数与强回波(35～55 dBZ)顶高具有对应关系,与-72℃冷云区面积及35 dBZ以上雷达组合反射率因子面积的变化特征相同.闪电活动集中位于TBB低值区的左侧和前部的亮温梯度大值区,对地面雷暴大风和强降水的可能发生位置具有判识作用.LMI与ADTD的比较发现二者所揭示的利奇马台前飑线闪电活动特征基本一致.

利用VLF/LF三维闪电监测定位资料,结合雷达、地面观测等资料,采用统计分析、对比分析法对福建2017—2020年33个冰雹云的闪电特征进行分析.结果表明:降雹前闪电频数峰值约有66.67％在50次/6 min以上,且降雹前总闪电频数出现跃增;70％雹暴单体平均递增率达4次/min以上,闪电快速跃增提前于降雹时间大多在10 min以上;成熟阶段云闪/总闪比值是3个阶段中最大,成熟阶段云闪是3阶段中最多的,初生发展阶段最小;80％冰雹云地面降雹落后于闪电峰值出现后的3～25 min,滞后于峰值时间最长超过30 min.这些结果可以为冰雹云的识别预警及人工防雹作业指挥提供参考.

In order to improve the availability of regional model precipitation forecast, this project intends to use the measured heavy rainfall data of dense automatic stations to carry out historical precipitation in the high resolution: the Severe Weather Automatic Nowcast System (SWAN) quantitative precipitation forecast and the High-Resolution Rapid Refresh (HRRR) regional numerical model precipitation forecast in short-term nowcasting aging. Based on the error analysis, the grid fusion technology is used to establish the measured rainfall, HRRR regional model precipitation forecast, and optical flow radar quantitative precipitation forecast (QPF) three-source fusion correction scheme, comprehensively integrate the revised forecasting effect, adjust the fusion correction parameters, establish an optimal correction plan, generate a frozen rolling update revised product based on measured dense data and short-term forecast, and put it into business operation, and perform real-time effect rolling test evaluation on the forecast product.

利用地面逐时降水资料、常规天气资料、雷达、卫星以及台风年鉴资料,对39个登陆福建不同地段的台风短时强降水空间、时间分布及强降水强度、落区、过程雨量分布及其与登陆时台风强度关系等进行统计分析,揭示登陆福建台风短时强降水规律,结果表明:(1)登陆中部台风强降水站数虽多,但单站强降水持续时间最短;登陆北部台风强降水站数虽少,但单站强降水持续时间最长.(2)强降水主要时段登陆北部、中部类是登陆前5小时至登陆后5小时,登陆南部及南海北上类是登陆时至登陆后15小时.此外,南海北上类及登陆北部类强降水落区多数在内核区;登陆中部类强降水落区在台风中心附近的频率是几类中最低的,大部分强降水落区在北侧的螺旋雨带上.

本文通过环境空气质量自动监测系统,利用2011年7月～2013年4月同仁气象局定时监测的PM10质量浓度,定量分析PM10质量浓度分布特征:PM10质量浓度分布有明显的月季变化.通过和同期观测的气象要素及日降水量对比分析可以得出的结论对开展的PM10预报起一定作用.

Typical fog cases were simulated by the MM5 model in 2009 in Shanxi province.The results indicate that the simulated temperature at 2 m height is about 2 ℃ low er than the observed one;the simulated relative humidity is about 15% higher than the observed one;the simulated w ind speed at 10 m height is about 0-2 m·s-1 greater than the observed one.The forecast indexes of fog include three conditions in Shanxi province,namely,the liquid w ater content at 20 m height is from 0.13 g·kg-1to 0.60 g·kg-1;there exists a temperature inversion layer betw een 20 m and 1500 m heights;the surface w ind speed at 10 m height is less than 4 m·s-1.A visibility forecast model is established by the daily mean visibility,relative humidity and air pollution index in Taiyuan.The forecast results of visibility by the MM5 and CAPPS are corrected using the observed data,and the revised forecast equation is developed.Tw o fog cases are forecasted using the revised equation,and it suggests that the model could be applied in Shanxi province.

The CINRAD has becomes one of the chief means to monitor short-time severe convective weather at present.A CINRAD product display system was developed so as to provide a convenient tool for users and improve the ability of processing data of observation software.The system can not only provide a platform for us to real-time browse radar product at any azimuth,but also provide more effective basis and support in weather forecasting and warning.Otherwise,it can provide a new idea for the development of CINRAD display system.

Two downburst events in Anhui on June 6th,2003and in Jiangsu on July 25th,2007were analyzed respectively based on Doppler radar data collected from Hefei and Yancheng radar sites.A serial of severe storms are growing out of multicell storms,accompanied with a shear line on the ground and sufficient moisture is provided by southwesterly flow on June 6th,2003.Another severe storm is growing out of two new cells triggered by the crushed bow-echo storm,and sustained by new cells from the gust front in front of the bow-echo on July 25th,2007.The results show that the obvious dropping of reflectivity factor core or cell top can produce downward tilt airflows at middle levels in the storms,which can be used to issue the downburst warning ;a downburst may initiated if a storm encounters with a shear line ;if C-VIL(cell-vertical integrated liquid water content) and CM(centroid of mass) keep stable in 6min,a downburst will generate during the following VCP(vertical coverage pattern) collection with 6min warning.

新一代多普勒气象业务雷达是目前监测短时强对流天气的主要设备之一，也可为危险性飞行天气的监测和预警提供有力保障。本文基于多普勒天气雷达的回波强度、径向速度、速度谱宽等产品数据，对4种危险性飞行天气（闪电、冰雹、强降水和中强湍流）设计了识别系统软件，并应用该软件对2014年9月28日江苏南京一次雷暴大风强对流天气进行了识别。结果表明，该识别预警系统能够将可能发生降雹区的位置和降雹区数量提前1 ~ 2个体扫识别出来，提前预警并标识出可能发生强降水的区域，提前30分钟预警闪电的结束，并能显示出不同强度等级的湍流区。