Climatic Characteristics of Hail Disaster and Division of Defense Region in Guizhou Province

[Objective] The aim was to study the climatic characteristics of hail disaster from 1984 to 2006 in Guizhou Province,China.[Method] Through statistical analysis,the climatic characteristics and disaster characteristics of hail from 1984 to 2006 in Guizhou Province were annalyzed and compared with previous results,then the classification standards of hail disaster were established,finally the defense zoning map of hail disaster in Guizhou Province was made.[Result] According to the statistical analysis on the historical data of hail disaster from 1984 to 2006,the frequency hail was 1 243 times in Guizhou in 23 years,that is,annual average frequency reached 54 times;annual average hailing days were 0.1-2.7 d in Guizhou Province,and the average frequency of hail was 3.8 times during each hail process;the frequency of hail was below 30 times in 52% of years and 30-80 times in 35% of years among 23 years.Hail could appear in the whole year,and 74% of hails occurred in spring,while winter had the fewest times.The results above were basically consistent with those of previous studies.Hail disaster mainly resulted in casualties and direct economic loss,and was divided into four grades according to direct economic loss,namely Grade I(extremely severe hail disaster),Grade II(severe hail disaster),Grade III(comparatively severe hail disaster) and Grade IV(medium hail disaster).The defense zoning map of hail disaster in Guizhou Province was made based on the frequency of hail and severe hail disaster,that is,the defense region at Grade I mainly distributed in Liupanshui City(in western Guizhou) and southern Guizhou;the defense region at Grade II was in the west,south and northeast of Guizhou Province,while the rest was at Grade III.[Conclusion] The study was of reference value for the defense of hail disaster in Guizhou Province.

安顺市空气质量特征与气象条件关系分析

选取2015—2018年安顺市空气质量小时数据和日数据,并结合同期气象观测资料和micaps资料对安顺市的空气质量特征与气象条件进行分析,结果表明:安顺市的空气质量优良率较高,达95%以上,主要污染物是PM2.5,其次是O3,冬季污染日最多,秋季次之,春、夏两季污染日数最少;当降水量在0~0.5mm、风速在3.1~5.0m/s、日照≤1h、相对湿度在60%~90%时,出现污染日的概率较大,分别为:82.6%、67.4%、76.1%、82.6%,1.0mm的降水会使空气中的吸湿性颗粒物的浓度增加,从而使空气质量变得更差;当日照时数<1h时,首要污染物以PM2.5为主,日照时数>1h时,特别是>8h时,首要污染物以O3为主;500hPa亚洲中高纬呈一槽一脊型,低纬南支槽建立并逐渐东移使安顺从偏西气流转为西南气流,空气质量逐渐转差,槽过转为西北气流时空气质量转好;当近地面吹偏南风时,空气质量较好,而吹偏北风时,空气质量转差;天空中云量较多时,大气层结较稳定,不利于污染物的扩散;污染物浓度与海平面气压呈正相关的关系。