Previous studies have recognized reflectivity maxima above the freezing level (RMAF) within stratiform precipitation over mountain slopes, however, quantitative studies are limited due to the lack of adequate identification criteria. Here, we establish an identification method for RMAF precipitation and apply it to the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) observations. Using the TRMM 2A25 product from 1998 to 2013, we show that the RMAF structure in reflectivity profiles can be effectively identified. RMAF exists not only in stratiform precipitation but also in convective precipitation. RMAF frequency is positively correlated with elevation, which is thought to be caused by enhanced updrafts in the middle layers of stratiform precipitation, or in the low to middle layers of convective precipitation over mountains. The average RMAF heights in stratiform and convective precipitation were 1.35 and 2.01 km above the freezing level, respectively, which is lower than previous results. In addition, our results indicate that the RMAF structure increased the echo top height and enhanced precipitation processes above the RMAF height, but it suppressed the downward propagation of ice particles and the near-surface rain rate. Future studies of orographic precipitation should take into account the impact of the RMAF structure and its relevant dynamic triggers.

先前的研究已经认识到在山坡上的层状降水中高于冻结水平（RMAF）的反射率最大值，但是，由于缺乏适当的识别标准，定量研究受到限制。在这里，我们建立了RMAF降水的识别方法，并将其应用于热带降雨测量团（TRMM）降水雷达（PR）的观测。使用1998年至2013年的TRMM 2A25产品，我们表明可以有效地识别反射率剖面中的RMAF结构。RMAF不仅存在于层状降水中，还存在于对流降水中。RMAF频率与海拔高度呈正相关，这被认为是由层状降水的中层或对流降水的低层至中层的上升气流增加引起的。层状和对流降水的平均RMAF高度分别比冻结水平高1.35和2.01 km，低于先前的结果。此外，我们的结果表明，RMAF结构增加了回波顶部高度，并在RMAF高度以上增强了降水过程，但抑制了冰粒的向下传播和近地表降雨率。未来对地形降水的研究应考虑RMAF结构及其相关动力触发因素的影响。但是它抑制了冰粒的向下传播和近地表降雨率。未来对地形降水的研究应考虑RMAF结构及其相关动力触发因素的影响。但它抑制了冰粒的向下传播和近地表降雨率。未来对地形降水的研究应考虑RMAF结构及其相关动力触发因素的影响。