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 >> Geography submitted time 2020-01-06 Cooperative journals: 《干旱区地理》
Abstract：利用2003—2014年5~9月中亚低涡发生时的AIRS Version 6 Level 2卫星资料，分析中亚低涡活动规律以及云中液态水空间分布。结果表明：（1） 北涡型中亚低涡共发生97次，南涡型共88次。中亚低涡中心更易向南移动。（2） 整体来看，云中液态水呈现山区多盆地少的趋势，在帕米尔高原、天山和昆仑山脉的山区以及咸海附近均大于100×10-6 kg·m-2。在准噶尔盆地、哈密盆地和塔里木盆地东部地区小于1×10-6 kg·m-2。（3） 中亚低涡发生路径越偏南，云中液态水柱越低。关于云中液态水柱，北涡路径较南涡路径更多。研究结果将为进一步认识中亚低涡强降水天气系统提供参考。
Subjects: Geosciences >> Geography submitted time 2019-01-11 Cooperative journals: 《干旱区地理》
Abstract：利用美国宇航局（NASA）发布的2003年1月～2015年12月的AIRS Standard Physical Retrieval Edition 6.0中的level2的反演数据，对新疆及其周边地区--特别是三大山区近13 a的可降水量的时空分布特征进行了研究。结果表明，从空间分布看，可降水量高值区主要集中在盆地地区，尤其在塔里木盆地、准最低值达1.92 mm；新疆及其周边地区可降水量所有格点13 a平均值来看，总体上，夏季最高，冬季最低。从时间分布看，对新疆及其周边地区、天山、昆仑山和阿尔泰山四个研究区域分别进行区域平均，发现以个区域年变化呈单峰型，从1～7月的可降水量逐渐增加，8～12月份的可降水量逐月减少；可降水量的整体年际变化趋势是一致的，2003—2010年呈上升趋势，2010—2015年呈下降趋势。
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