Subjects: Geosciences >> Atmospheric Sciences submitted time 2023-02-27 Cooperative journals: 《干旱区地理》
Abstract： Previous studies have shown that the Emanuel scheme performs relatively well in simulating temperature and precipitation in East Asia. However, the user’s guide of RegCM4.6 points out that the Emanuel scheme tends to produce excessive precipitation over lands, especially in some intense individual precipitation events. In contrast, the Grell scheme tends to produce weak precipitation over tropical oceans. Therefore, the new version of the regional climate model RegCM4.6 has incorporated the Mix cumulus convective parameterization scheme, which means that the Emanuel scheme can be used over oceans and the Grell scheme over land, to compensate for the deficiencies of a single scheme. Previous validation studies have mainly focused on temperature and precipitation, and few studies have been conducted on the Mix scheme. The MODIS product from January 1st , 2016, to December 31st , 2016, was used as a reference to evaluate the simulation results of cloud fraction (CF), ice water path (IWP), and liquid water path (LWP) in East Asia from the Emanuel and Mix schemes in RegCM4.6 at various time scales. Some statistical parameters were calculated, such as the correlation coefficient (r), mean absolute error (MAE), mean bias error (MBE), and root mean square error (RMSE). The results were as follows. (1) The simulated CF were slightly overestimated in the northwest and mainly underestimated in the southeast roughly bounded by the Hu Huanyong line. The performance of the two schemes in simulating CF was the best in summer and the worst in winter. In the four seasons, the absolute values of MAE, MBE, and RMSE of the Mix scheme were generally lower than those of the Emanuel scheme. (2) The systematic deviations of IWP were negative in the whole of East Asia. Except in summer, the IWP from the two simulations and MODIS was significantly negatively correlated in the other three seasons, indicating that it was a challenge to accurately simulate physical processes related to ice particles in the cloud. (3) The LWP was underestimated by the two schemes in the Qinghai Tibet Plateau and Eastern Ocean and was overestimated in southern, central, and northern China, but the annual MBE of the Mix scheme were closer to 0. The performances of the two schemes were similar in winter. In the other three seasons, the absolute values of MAE, MBE, and RMSE of the Mix scheme were less than those of the Emanuel scheme, and the differences in MAE for the two schemes were 21-39 g·m-2 . In conclusion, the Mix scheme is more suitable to simulate cloud water resources in East Asia. This study will contribute to the exploitation of cloud water resources in East Asia and provide a reference for the selection and improvement of the cumulus convection parameterization scheme in a regional climate model.
Subjects: Geosciences >> Geography submitted time 2021-08-12 Cooperative journals: 《干旱区研究》
Abstract：利用2015-06—2016-05月新疆区域地面观测的总云量小时数据，对比分析了FY-2F/CTA与地面观测云量的相关性和一致性，开展了FY-2F云量产品在新疆区域的分析检验。结果表明：（1）FY-2F/CTA与地面人工观测总云量的相关性较好，天山以北区域（含天山山区）冬季除外。（2）FY-2F/CTA与地面人工观测总云量的一致率为51.5%，南北疆差别不大，均是夏、秋季较高，但天山以北区域冬季较低，南疆春季较低；卫星反演总云量整体比地面观测值偏低，即呈高偏弱率低偏强率分布，南疆区域偏低最为明显。（3）不同云量等级下，一致率与总云量呈反比，即晴天、少云状况下的一致率较高，多云、阴天条件下的一致率较低。（4）沙尘会降低FY-2F/CTA判识的一致率，增大其偏弱率，但是对于有、无云的判识影响不大。本研究考虑了不同季节、不同云量等级以及有无沙尘影响，对FY-2F/CTA产品进行了评估，研究结果为干旱区总云量的卫星反演及应用提供了重要参考。
Subjects: Geosciences >> Atmospheric Sciences submitted time 2019-11-14 Cooperative journals: 《干旱区研究》
Abstract： 在中尺度数值模式中，选用不同的参数化方案对降水的模拟和预测效果会有很大影响，合理选择参数化方案可以提高预测准确性。为此，本文使用中尺度预报模式WRF3.8 (Weather Research and Forecasting model, WRF) 版本，采用3 km和9 km两层嵌套网格，利用ECMWF（European Centre for Medium Range Weather Forecasts）再分析资料作为初始场和边界条件，对新疆地区4次暴雨过程进行模拟，采用TS （Threat Score） 评分评估了Lin方案、WSM6方案、Thompson方案和WDM6方案4种云微物理参数化方案对新疆地区暴雨模拟的适用性。结果表明：Thompson方案在站点降雨量为小雨（0.1~5.0 mm）和中雨（5.1~10.0 mm）的预报模拟中具有优势，其他3种云微物理参数化方案均在不同程度上存在漏报情况，从相关系数上判断，Thompson方案模拟效果略优于其他方案，适用于多小雨、中雨的新疆地区，但4种云微物理参数化方案在大到暴雨降水等级的预报效果都不是很好，这也正是WRF模式在新疆地区需要改进的地方。
Subjects: Geosciences >> Atmospheric Sciences submitted time 2019-11-14 Cooperative journals: 《干旱区研究》
Abstract： 采用2017年辐射数据，研究了新疆11个地面观测站点的太阳总辐射时空分布特征，发现总辐射辐照度日变化呈单峰分布，日照时数夏季最高，约17 h，春秋季次之，分别为14 h、15 h，冬季最小，仅为12 h；季节平均最大值出现在和田的春季，为589.61 W·m-2，最小仅约为102.29 W·m-2，出现在乌鲁木齐的冬季。卫星反演辐射空间分布特征显示：春季南疆辐照度明显高于北疆，夏季平均辐照度分布与全年最为相似，冬季次之，秋季南北疆差异不大，季节差异在阿克苏最小。从卫星和地面辐射数据的拟合分析可见，方差分析中南疆F值均较高，最高达6 215.53，即晴空条件下，CERES/SSF卫星资料在南疆的反演效果优于北疆及吐-哈盆地。
Subjects: Geosciences >> Atmospheric Sciences submitted time 2019-10-11 Cooperative journals: 《干旱区研究》
Abstract： 中亚低涡是新疆及中亚地区主要降水系统，为了揭示其影响下的大气降水潜力，利用2003—2014年夏半年中亚低涡发生时的AIRS Version 6 Level 2卫星资料，对夏半年中亚低涡降水系统月际变化和不同类型路径的大气可降水量分布规律进行分析。结果表明：① 中亚低涡的南涡与北涡发生率明显不同。北涡占中亚低涡总发生率的68.31%，南涡占31.69%。其中，7、8月间中亚低涡发生频次最高。② 按照中亚低涡不同路径分类来看，各路径发生率明显不同，其中，向东南方向移动的中亚低涡发生率最高。③ 从月际变化来看， 5—9月平均大气可降水量整体分布趋势为中亚地区高于中国新疆地区。新疆吐鲁番盆地和塔里木盆地地区高于沿山脉分布的地区。④ 从路径类型来看，北涡各路径平均大气可降水量分布趋势整体相似。各路径均有26 mm以上大范围高值区，南涡各路径含量整体偏小，大都在18 mm以下。上述研究将为新疆和中亚地区突发性强降水天气预报预警以及人工增水提供参考。
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