陇东庆阳一次寒潮、霜冻天气成因分析及其对农业的影响

Analysis on the Causes of a Cold Wave and Frost Weather in Longdong Area and Its Impact on Agriculture

基于MICAPS常规观测资料、FY-2G红外云图资料和庆阳市8个国家自动气象观测站观测资料,对2020年4月11—13日发生在庆阳的一次寒潮、霜冻天气进行了成因分析,并分析了霜冻对于农业的影响。结果显示:此次过程高空环流场属于典型的横槽转竖型,贝加尔湖高压脊减弱南压,横槽转竖引导冷空气南下爆发,造成寒潮霜冻天气;此次霜冻属于混合型霜冻,中低层冷平流强度较强,持续时间长,冷平流中心位于500 hPa附近;11日冷锋过境后庆阳晴空、微风、湿度低,辐射降温强烈。霜冻后最大气温日较差达到了21.2℃,最大地面温度日较差53.9℃,温度迅速升高,使得霜冻灾害进一步升级。庆阳市2020年1—4月降水量偏少,频繁强霜冻天气使得寒旱叠加,对农作物造成严重影响。

Based on MICAPS conventional observation data,FY-2G infrared cloud image data and observation data from 8 national automatic meteorological observation stations in Qingyang,the causes of a cold wave and frost occurred in Qingyang from April 11 to 13 on 2020 were analyzed,and the impact of frost on agriculture was analyzed.According to the research results,the high-altitude circulation field during this process is a typical horizontal trough-to-vertical type.The Baikal high pressure ridge weakens the south pressure,and the horizontal trough turns to vertical to guide the cold air to erupt southward,resulting in cold wave and frosty weather.This frost was a mixed type of frost,with strong cold advection in the middle and low layers and a long duration.The center of cold advection is located near 500 hPa.After the passage of the cold front on April 11,Qingyang had clear sky,light wind,low humidity,and strong radiation cooling.After the frost,the maximum daily temperature range reached 21.2℃,and the maximum daily range of ground temperature was 53.9℃.The temperature increased rapidly,which further escalated the frost disaster.Qingyang has less precipitation from January to April on 2020,and frequent and strong frosts cause cold and drought to superimpose,which has a serious impact on crops.