Subjects: Geosciences >> Geography submitted time 2024-03-01 Cooperative journals: 《干旱区研究》
Abstract： Based on hourly precipitation observation data from 340 meteorological stations in Gansu Province from April to October 2013 to 2022, the refined evolution characteristics of warm season precipitation in Gansu Province on a diurnal variation scale were revealed. Discussions and analyses were conducted in different regions, providing a scientific reference for the study of extreme precipitation events in Gansu. The results show the following: (1) the daily peak of precipitation and precipitation intensity in the warm season in Gansu mainly occurs between 10:00 and 13:00, the daily peak of precipitation frequency primarily occurs between 22:00 and 01:00 at night, and the daily precipitation variation has obvious seasonal differences. There is a relatively concentrated distribution of autumn rain in the central and southern parts of Gansu. (2) The diurnal variation of precipitation has distinct regional characteristics. Precipitation in the Qilian Mountains and the plateau slopes of central Gansu mainly occurs during the day, with intense precipitation dominating around noon, marking the peak of daytime precipitation. Conversely, in western Hexi, the peak and frequency of daily precipitation generally occur at night, with occasional sudden heavy rainfall between 18:00 and 21:00. In southeast and eastern Gansu, the precipitation is nonuniformly distributed; nighttime rain is common due to the frequency of precipitation peaks during the night, but strong precipitation periods tend to occur in the afternoon and morning, respectively. (3) The precipitation characteristics of different durations are different. For short-term precipitation events with a duration of 6 h and below, the daily variation of precipitation is mostly“bimodal type.”Long-term precipitation events lasting more than 6 h are“unimodal type”and primarily begin in the evening, reach their peak at night, and end at noon.
Subjects: Geosciences >> Geography submitted time 2023-09-27 Cooperative journals: 《干旱区地理》
Abstract：甘肃省是我国地质灾害多发的省份之一，降水型地质灾害占比重。利用甘肃省20132021年410月地质灾情数据、加密降水观测资料和地面-雷达-卫星三源融合降水分析产品（CMPAS），选取有效雨量代表降水致灾因子，建立黄土高原和陇南山地有效雨量致灾概率方程，以有效雨量致灾概率、地质灾害潜在危险度、易损度为因子构建甘肃省地质灾害气象风险精细化网格预警模型，并应用实况降水资料和兰州中心气象台精细化网格定量降水预报产品，建立地质灾害气象风险精细化网格预报试验，检验模型的预警效果。结果表明：（1） 基于有效雨量致灾概率分别给出了黄土高原和陇南山地地质灾害气象风险蓝色、黄色、橙色和红色预警的临界雨量阈值，其中，陇南山地蓝色和红色预警临界雨量阈值分别为40.6 mm和113.5 mm，远高于黄土高原的18.0 mm和73.6 mm。（2） 确定了甘肃省地质灾害气象风险蓝色、黄色、橙色和红色预警的风险度判别指标，数值介于0.004~1.000，其中0.336~1.000表示红色预警。（3） 甘肃省地质灾害气象风险精细化网格预警模型能够较好预警地质灾害事件，各等级预警的比例合理，且能有效降低高等级预警率和空报率，该模型具有较强的地质灾害气象风险预警能力。
Subjects: Geosciences >> Geography submitted time 2022-01-26 Cooperative journals: 《干旱区研究》
Abstract：利用20192020年59月ECMWF（European Center for Medium-Range Weather Forecast）、GRAPES-GFS（中国气象局GRAPES 全球数值预报业务系统，Global/Regional Assimilation and Prediction System-Global ForecastSystem）大尺度数值模式36 h预报时效的24 h降水量预报和加密降水观测资料，基于CRA空间检验技术识别、分离青藏高原东北侧暴雨目标（ECMWF模式18个，GRAPES-GFS模式11个），定量分析了两种模式对暴雨预报的空间误差（落区、强度和形态误差）特征，总结大尺度数值模式在青藏高原东北侧暴雨预报中的适用性。结果表明：（1）两种模式的降水预报形态误差占比均最大。ECMWF预报的强度误差占比最小，落区误差次之，而GRAPES-GFS的落区误差占比最小，强度误差次之。（2）两种模式预报的暴雨落区位置均较实况偏西偏北。暴雨大值中心ECMWF偏西偏南，而GRAPES-GFS仅偏西。（3）对暴雨雨区面积的预报两种模式均明显偏小，容易造成暴雨漏报，对最大降水量和平均雨强的预报GRAPES-GFS模式均偏弱超过40%，ECMWF预报的平均雨强偏弱11.49%，最大降水量偏强1.47%。（4）两种模式对甘肃陇东南地区和陕西西南部的暴雨预报效果较好，而对陕北及宁夏等偏北地区的预报效果较差。
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