2009-2017年辽宁省降雪含水比变化特征研究

降雪含水比（Snow-to-liquid ratio，缩写为SLR）是降雪深度预报中将定量降水预报（Quantitative precipitation forecast，缩写为QPF）转化为雪深预报所必须的重要参数。利用2009-2017年冬半年辽宁省国家基本站逐小时降水量、积雪深度加密观测资料以及地面气温、地面温度、极大风速、天气现象等资料，通过制定适合本研究的质量控制标准，严格筛选降雪事件，分析辽宁省SLR的变化特征以及气温对降雪含水比的影响，研究结果表明：（1）辽宁省小时SLR的平均值为11，略高于经验值10，虽然SLR变化范围跨度很大，但主要集中在2~20内变化，而SLR大于30的极端值出现频率较低；（2）平均SLR在辽宁省不仅存在明显的空间分布差异，还存在显著的月变化特征；（3）地面气温与SLR有很好的相关性，平均SLR在不同气温区间变化明显，在-15℃附近SLR存在峰值，峰值前随气温降低平均SLR明显增大，而峰值后随着气温降低SLR突然减小。研究结果为今后辽宁冬季降雪深度预报中合理使用SLR这一重要参数提供参考。

Variations of snow-to-liquid ratio in Liaoning Province from 2009 to 2017

Snow-to-liquid ratio(SLR)is an important parameter,which is needed to convert quantitative precipitation forecast(QPF)into snowfall depth forecast during forecasting snowfall depth. In this paper,using the hourly observed precipitation and snow depth data and other data such as surface air temperature,surface temperature,maximum wind speed and weather phenomena from national base stations during winter half years from 2009 to 2017 in Liaoning Province,by establishing quality control standards suitable for this study,the snowfall events were strictly selected,then variations of SLR and influence of temperature on SLR were analyzed in Liaoning Province. The results show that mean SLR value was 11,which was slightly higher than an empirical SLR value of 10. Although the variation range of SLR was large,it mainly changed from 2 to 20,with the extreme value of SLR greater than 30 by accident. In Liaoning Province,there were not only obvious spatial distribution difference in mean SLR,but also obvious monthly variations. There was a good correlation between SLR and surface air temperature;the change of mean SLR was obviously in different temperature ranges;a peak of SLR appeared around -15℃;mean SLR increased significantly with temperature decrease before the peak;and at lower temperature there was a return to lower SLR. The results of this study would be useful for rational use of SLR in future winter snowfall depth forecasting in Liaoning Province.