Under the effect of global warming, more precipitation will shift to rainfall in cryospheric regions. Considering the influence of the precipitation type on surface energy and mass cycles, it is important to determine the specific precipitation features and to classify the precipitation type in key areas correctly. We analyzed the monthly distribution, variations in each precipitation type’s annual days, and trends based on daily precipitation and air temperature observations from six tripolar stations. The results indicated that snow dominated the precipitation type at Zhongshan station (69.4°S, 76.4°E) throughout the year, while the Greatwall station (62.2°S, 59.0°W) exhibited a relatively diverse precipitation type distribution and significant seasonal cycles. Compared to the Greatwall station, every precipitation type was less frequently encountered at the Barrow (71.3°N, 156.8°W), Coral Harbour (64.2°N, 83.4°W), Linzhi (29.6°N, 94.5°E), and Maqu stations (34°N, 102.1°E), in which all the sites demonstrated classical reverse seasonal variation. A consistent trend across the years was found regarding the trends of the different precipitation types, except at the Greatwall and Coral Harbour stations. Due to snow/rain conditions partly converting into sleet conditions, which may be related to air temperature changes and synoptic atmospheric activities, inconsistent increasing trends of the sleet days were observed compared to the snow/rain days. Furthermore, a hyperbolic parameterized model was also fitted to determine the air temperature threshold of precipitation type transitions in this paper. According to the threshold comparison results, a warm bias in the temperature threshold was found at the warm stations. We also proposed that high relative humidity and low freezing levels were the likely reasons for the ERA5 reanalysis datasets. Finally, this paper’s fitted parameterized model was proven to perform better than the ERA5 reanalysis datasets through validation. This preliminary research provides observational evidence and possible interpretation of the mechanism of precipitation type changes in tripolar areas.

在全球变暖的影响下，更多的降水将转移到冰冻圈地区的降雨中。考虑到降水类型对表面能和质量循环的影响，确定特定的降水特征并正确分类关键区域的降水类型非常重要。我们基于六个三极站的每日降水量和气温观测结果，分析了月度分布，每种降水类型年日的变化以及趋势。结果表明，中雪站全年降水以雪为主（69.4°S，76.4°E），而长城站（62.2°S，59.0°W）则表现出相对不同的降水类型分布和明显的季节周期。与长城车站相比，在巴罗（71.3°N，156.8°W），珊瑚港（64.2°N，83.4°W），临zhi（29.6°N，94.5°E）和玛曲站（34°N），每种降水类型都较少遇到，102.1°E），其中所有站点都表现出经典的逆季节变化。除长城和珊瑚港站外，多年来不同降水类型的趋势一直保持一致。由于雪/雨状况部分转变为雨夹雪状况，可能与气温变化和天气大气活动有关，因此与雪/雨天相比，雨夹雪日的上升趋势不一致。此外，本文还拟合了双曲线参数化模型来确定降水类型转变的气温阈值。根据阈值比较结果，在温暖站点发现温度阈值存在温暖偏差。我们还提出，较高的相对湿度和较低的冻结水平是ERA5重新分析数据集的可能原因。最后，通过验证，证明了本文拟合的参数化模型的性能优于ERA5重新分析数据集。这项初步研究为三极地区降水类型变化的机理提供了观测证据和可能的解释。通过验证，证明了本文拟合的参数化模型的性能优于ERA5重新分析数据集。这项初步研究为三极地区降水类型变化的机理提供了观测证据和可能的解释。通过验证，证明了本文拟合的参数化模型的性能优于ERA5重新分析数据集。这项初步研究为三极地区降水类型变化的机理提供了观测证据和可能的解释。