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: Environmental Sciences, Resource Sciences >> Basic Disciplines of Environmental Science and Technology submitted time 2019-03-07 Cooperative journals: 《干旱区地理》
Abstract：利用NASA发布的2008—2015年CloudSat卫星的2B-CWC-RO、2B-CLDCLASS、2C-SNOW-PROFILE和地面气象站的观测资料，对北疆沿天山及其周边区域内21次强降雪天气降雪前和降雪期间卫星过境时云宏微观特征进行了对比分析。本文将研究区域分为了北疆沿天山西部和中部地区，分析结果表明：（1）降雪前和降雪期间的云类型以层云、积云、高层云和深对流云为主。（2）降雪前冰粒子等效半径均值分布在58.65~67.29 μm之间，冰粒子数浓度的均值在41.2~76.5 L-1之间，冰水含量的均值在25.4~135.1 mg·m-3之间，雪水含量均值在28.0~88.0 mg·m-3之间，降雪强度均值在0.08~0.36 mm·h-1之间。（3）降雪前冰粒子等效半径、冰粒子数浓度、冰水含量、雪水含量和降雪强度均值分别比降雪期间大2.9 %、6.2 %、34.4 %、36.4 %和18.7 %，且高值区主要集中在北疆沿天山西部地区。
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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