We investigated the cloud liquid water (CLW) and rain liquid water (RLW) during weak precipitations (rain rate below 12 mm/h) using microwave radiometer and microrain radar measurements collected by the Integrative Monsoon Frontal Rainfall Experiment over central China in 2018. The CLW path increased sharply from 0.6 to 4.1 mm for precipitation clouds. RLW path presented a similar trend, although it had a larger correlation coefficient with rain rate. Precipitation efficiency reached up to ~50% and then clearly decreased as precipitation weakened. Because weak precipitation is mostly formed in stable nimbostratus, CLW content (CLWC) during precipitation tends to has a quasi‐normal distribution with mode at 0.38 g/m³, whereas RLW content (RLWC) shows a positively skewed distribution with mode at 0.06 g/m³. Normalized CLWC initially increases then decreases with height in nonprecipitation clouds but varies slightly in precipitation clouds due to relatively monodispersed droplets in the weaker convective motion. CLWC derived from millimeter‐wave cloud radar (MMCR) shows similar vertical distribution but with larger values. The mean normalized CLWCs are 0.06 and 0.38 g/m³ for nonprecipitation and precipitation clouds, respectively. RLWC varies slightly with height with a mean of 0.22 g/m³ because both the collision and breakup of raindrops are weak. A case study showed different distributions and vertical structures of CLWC and RLWC in various stages of precipitation. Thicker clouds result in larger CLWC and RLWC, which will cause greater rain rate. This qualitatively explains relationships among cloud thickness, CLW, RLW, and rain rate in precipitation during the monsoon.

中文翻译：

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季风期间微波辐射计和微雨雷达观测获得的云液态水和雨液态水的比较研究

我们使用微波辐射计和微雨雷达测量方法（由中部地区在2018年中部进行的季风前锋降水综合试验收集），研究了弱降水（降雨速率低于12 mm / h）期间的云状液态水（CLW）和雨状液态水（RLW）。降水云的CLW路径从0.6毫米急剧增加到4.1毫米。尽管RLW路径与降雨率具有较大的相关系数，但其趋势相似。降水效率达到〜50％，然后随着降水减弱而明显下降。由于弱降水主要在稳定的云母层中形成，因此降水过程中的CLW含量（CLWC）趋于具有准正态分布，其模式为0.38 g / m ³，而RLW含量（RLWC）则呈现正偏分布，其模式为0.06 g /米³。在非降水云中，归一化的CLWC最初随着高度的增加而增加，然后下降，但由于较弱的对流运动中的液滴相对单一分散，在降水云中的变化很小。来自毫米波云雷达（MMCR）的CLWC表现出相似的垂直分布，但具有较大的值。非降水云和降水云的平均归一化CLWC分别为0.06和0.38 g / m ³。RLWC随高度略有变化，平均值为0.22 g / m ³因为雨滴的碰撞和破裂都很弱。案例研究表明，在降水的不同阶段，CLWC和RLWC的分布和垂直结构不同。较厚的云导致较大的CLWC和RLWC，这将导致较大的降雨率。定性地解释了季风期间云层厚度，CLW，RLW和降雨率之间的关系。