长白山麓夏秋季气态和液态水分布特征

Distribution characteristics of gaseous and liquid water at the foot of Changbai Mountain in summer and autumn

利用2019—2020年6—10月中国气象局吉林云物理野外科学试验基地MWP967KV型多通道微波辐射计、地面雨量计及L波段探空雷达资料,分析了长白山麓夏秋季大气中气态和液态水分布及其在降水前的演变特征。结果表明:微波辐射计反演数据与探空雷达数据具有较好的相关性,但反演值整体偏大。大气可降水量(PWV)和液态水路径(LWP)呈一峰一谷日变化特征,峰值出现在夜间而谷值出现在白天,有降水时峰值出现在01:00—03:00,谷值出现在11:00前后。受长白山地形和森林植被影响,PWV和LWP月平均最大值分别出现在8月和9月。PWV在降水前和降水中分布频率均呈现先升后降趋势,而降水前LWP在0.00~0.42 mm内频率占比最高;降水强度越强,PWV及LWP频率分布越集中,PWV大于45 mm、LWP大于4.20 mm出现强降水的可能性较大。降水开始前1 h内LWP和PWV均出现跃增,LWP跃增幅度更明显,该特征可作为降水临近预报、人工增雨作业条件分析的参考指标。

Utilizing the MWP967KV multi-channel microwave radiometer,ground-based rain gauge,and L-band sounding radar data from the China Meteorological Administration Jilin Cloud Physics Field Experiment Base during June to October from 2019 to 2020,the distribution of gaseous and liquid water in the atmosphere at the foot of Changbai Mountain in summer and autumn and its evolution characteristics before precipitation were analyzed.The results show that there is good correlation between the microwave radiometer retrieved data and sounding radar data,though the retrieved values are generally higher.The atmospheric precipitable water vapor(PWV)and liquid water path(LWP)exhibit the diurnal variation characteristic with the peak at night and the valley in the day.The peak appears between 01:00-03:00 during precipitation,while the valley appears around 11:00.The monthly average maximum values of PWV and LWP appear in August and September respectively,because of the influence of the topography and forest vegetation at Changbai Mountain.The distribution frequency of PWV shows a rising and then a falling trend before and during precipitation,whereas the frequency ratio of LWP in the range of 0.00~0.42 mm is the highest before precipitation.The stronger the precipitation intensity is,the more concentrated the frequency distribution of PWV and LWP is,with a greater likelihood of heavy precipitation for PWV greater than 45 mm and LWP greater than 4.20 mm.A surge in both LWP and PWV occurs within 1 h before precipitation starts,with a more pronounced increase in LWP,indicating that this characteristic can serve as a reference index for the analysis of precipitation approaching forecast and artificial rain enhancement operations.