黄河中游地区MCC天气学分型及结构差异分析
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摘要
利用2005——2017年卫星、实况探测、L波段探空秒数据和NCEP/NCAR FNL 1°×1°再分析等资料,采用天气学和动力诊断分析等方法,对黄河中游地区中尺度对流复合体(mesoscale convective complex,MCC)进行天气学分型,并对其结构特征及差异进行分析。结果表明:1)黄河中游地区MCC主要生成在夏季,多在傍晚至次日凌晨发展成熟,生命史长、移动缓慢,以暴雨及以上量级降水为主,雨强大,地域差异明显。2)依据200 hPa环流形势,将MCC分为3个主型,结合500 hPa形势特点,每个主型下分为不同副型。通过分析不同分型下MCC环境场及物理量空间结构特征及差异,提炼MCC强降水预报关键技术,建立MCC强降水预报物理模型。3) MCC形成在低层比湿和能量扰动的正值中心附近,在低层扰动梯度大值区、靠近正中心的区域发展成熟。扰动正值中心所在高度、中心强度以及正扰动的厚度等物理因子与MCC发展以及降水强度关系密切。4)不同分型下,MCC不同生命阶段云系及环境大气的垂直变化存在明显差异。云顶高度下降,湿层加厚,凝结高度降低,逆温层消失,是MCC达到成熟的先兆信号。5)在200 hPa南亚高压稳定背景下,地面存在次天气尺度冷锋、中尺度高压和冷池;中尺度高压作用明显小于冷池,冷池强度和维持时间与MCC降水强度和持续时间密切相关。在200 hPa深厚低槽和西北急流或急流分支背景下,地面无冷池和中尺度高压形成,低层入流风速和温度梯度的加大是MCC发展成熟的重要因素,中尺度露点锋对MCC强降水的触发作用不可忽视。
Based on satellite data,observational data,L-band second-level radiosonde data,and NCEP/NCAR 1°× 1° reanalysis data from 2005 to 2017,the synoptic patterns of mesoscale convective complex( MCC) over the middle reaches of the Yellow River are classified,and their structural characteristics are comparatively analyzed by synoptic and dynamic diagnostic analysis. The results are listed as below. 1) In the middle reaches of the Yellow River,MCCs are mainly generated in the summer and generally develop to be mature from dusk till dawn with a long life cycle and slow movements. MCCs mainly produce rainstorm or above-level precipitation with high intensity and significant regional distribution differences. 2) According to the circulation at 200 hPa,the synoptic situation of MCCs are classified into three main patterns,and each main pattern is classified into different secondary patterns according to the circulation at 500 hPa. By comparative analysis of the structural characteristics,environmental conditions, and physical parameters of different MCCs patterns, the key forecasting techniques of heavy MCC precipitation are summarized and the physical models of MCCs are set up.3) MCCs occur near the positive center of specific humidity and energy disturbance at the lower layer and develop to be mature at areas of great disturbance gradient near the positive center. The development of MCCs and the precipitation intensity have close relationships with the height,intensity,and thickness of the positive disturbance. 4) Though cloud system and vertical variations of ambient atmosphere display obvious differences in different life stages of different MCC patterns,the descent of cloud top,the thickening of moisture level,the decrease of condensation level,and the disappearance of inversion layer are premonitory signals of MCCs developing to be mature. 5) Under the background of stable South Asia high at 200 hPa,there are subsynoptic-scale cold front,mesoscale high,and cold pool on the surface.The impact of mesoscale high is less than that of cold pool,whose intensity and duration are closely related to intensity and duration of MCC precipitation. While under the background of thick upper trough and northwestern jet stream or jet stream branch at 200 hPa,there are no cold pool and mesoscale high on the surface. The increase of inflow wind speed and temperature gradient at the lower layer are the main factors for MCCs developing to be mature. The triggering mechanism of mesoscale dew-point front on heavy MCC precipitation cannot be ignored.
Based on satellite data,observational data,L-band second-level radiosonde data,and NCEP/NCAR 1°× 1° reanalysis data from 2005 to 2017,the synoptic patterns of mesoscale convective complex( MCC) over the middle reaches of the Yellow River are classified,and their structural characteristics are comparatively analyzed by synoptic and dynamic diagnostic analysis. The results are listed as below. 1) In the middle reaches of the Yellow River,MCCs are mainly generated in the summer and generally develop to be mature from dusk till dawn with a long life cycle and slow movements. MCCs mainly produce rainstorm or above-level precipitation with high intensity and significant regional distribution differences. 2) According to the circulation at 200 hPa,the synoptic situation of MCCs are classified into three main patterns,and each main pattern is classified into different secondary patterns according to the circulation at 500 hPa. By comparative analysis of the structural characteristics,environmental conditions, and physical parameters of different MCCs patterns, the key forecasting techniques of heavy MCC precipitation are summarized and the physical models of MCCs are set up.3) MCCs occur near the positive center of specific humidity and energy disturbance at the lower layer and develop to be mature at areas of great disturbance gradient near the positive center. The development of MCCs and the precipitation intensity have close relationships with the height,intensity,and thickness of the positive disturbance. 4) Though cloud system and vertical variations of ambient atmosphere display obvious differences in different life stages of different MCC patterns,the descent of cloud top,the thickening of moisture level,the decrease of condensation level,and the disappearance of inversion layer are premonitory signals of MCCs developing to be mature. 5) Under the background of stable South Asia high at 200 hPa,there are subsynoptic-scale cold front,mesoscale high,and cold pool on the surface.The impact of mesoscale high is less than that of cold pool,whose intensity and duration are closely related to intensity and duration of MCC precipitation. While under the background of thick upper trough and northwestern jet stream or jet stream branch at 200 hPa,there are no cold pool and mesoscale high on the surface. The increase of inflow wind speed and temperature gradient at the lower layer are the main factors for MCCs developing to be mature. The triggering mechanism of mesoscale dew-point front on heavy MCC precipitation cannot be ignored.
引文
[1]马禹,王旭,陶祖钰.中国及其邻近地区中尺度对流系统的普查和时空分布特征[J].自然科学进展,1997,7(6):701-706.
[2]赵桂香,王晓丽,吴洪.黄河中游地区中尺度对流系统的统计特征[J].干旱气象,2016,34(6):1016-1026.
[3]覃丹宇,江吉喜,方宗义,等.MCC和一般暴雨云团发生发展的物理条件差异[J].应用气象学报,2004,15(5):590-600.
[4]侯建忠,孙伟,杜继稳.青藏高原东北侧一次MCC的环境流场及动力分析[J].高原气象,2005,24(5):805-810.
[5]黎惠金,李向红,黄芳,等.广西一次特大暴雨的MCC演变过程及结构特征分析[J].高原气象,2013,32(3):806-817.
[6]赵桂香,王晓丽,王一颉.黄河中游地区初春与盛夏MCC结构特征比较分析[J].高原气象,2017,36(6):1638-1654.
[7]高帆,张永婧,李瑞,等.2015年8月3日山东西北部暴雨过程的中尺度特征分析[J].海洋气象学报,2017,37(2):96-101.
[8]赵桂香,薄燕青,邱贵强,等.黄河中游一次大暴雨的观测分析与数值模拟[J].高原气象,2017,36(2):436-454.
[9]黄治勇,谌伟,张文,等.长江中下游深秋季节一次MCC过程的成因[J].长江流域资源与环境,2012,21(8):1025-1031.
[10]侯淑梅,孙鹏程,杨璐瑛,等.环境场条件对雷暴传播运动影响实例分析[J].海洋气象学报,2018,38(4):58-70.
[11]杨忠明,吴浙红,王兴菊.贵州中南部2次MCC致洪暴雨的综合分析[J].干旱气象,2013,31(2):362-372.
[12]杨晓霞.副热带高压边缘连续两次强降水形成机制分析[J].海洋气象学报,2017,37(3):62-72.
[13]张立祥,李泽椿.一次东北冷涡MCS边界层特征数值模拟分析[J].气象学报,2009,67(1):75-82.
[14]朱义青,郭宝阳,王玉亮,等.一次低槽冷锋暴雨数值模拟和诊断分析[J].山东气象,2016,36(3):13-19.
[15]赵桂香,赵建峰,杨东,等.山西一次大暴雨过程云图及环境场的特征分析[J].高原气象,2013,32(6):1747-1757.
[16]井喜,屠妮妮,井宇,等.中国MCC时空分布与天气学特征分析[J].高原气象,2013,32(6):1597-1607.
[17]MADDOX R A.Mesoscale convective complexes[J].Bull Ameteor Soc,1980,61(11):1374-1387.
[18]MADDOX R A.Large-scale meteorological conditions associated with mid-latitude mesoscale convective complexes[J].Mon Wea Rev,1983,111(7):1475-1493.
[19]高守亭,孙建华,崔晓鹏.暴雨中尺度系统数值模拟与动力诊断研究[J].大气科学,2008,32(4):854-866.
[20]冉令坤,齐彦斌,郝寿昌.“7.21”暴雨过程动力因子分析和预报研究[J].大气科学,2014,38(1):83-100.
[21]ROMERO R C,DOSWELL C AⅢ,RIOSALIDO R.Observations and fine-grid simulation of a convective outbreak in northeastern Spain:Importance of diurnal forcing and convective cold pools[J].Mon Wea Rev,2001,129(9):2157-2182.
[22]肖现,陈明轩,高峰,等.弱天气系统强迫下北京地区对流下山演变的热动力机制[J].大气科学,2015,39(1):100-124.
[2]赵桂香,王晓丽,吴洪.黄河中游地区中尺度对流系统的统计特征[J].干旱气象,2016,34(6):1016-1026.
[3]覃丹宇,江吉喜,方宗义,等.MCC和一般暴雨云团发生发展的物理条件差异[J].应用气象学报,2004,15(5):590-600.
[4]侯建忠,孙伟,杜继稳.青藏高原东北侧一次MCC的环境流场及动力分析[J].高原气象,2005,24(5):805-810.
[5]黎惠金,李向红,黄芳,等.广西一次特大暴雨的MCC演变过程及结构特征分析[J].高原气象,2013,32(3):806-817.
[6]赵桂香,王晓丽,王一颉.黄河中游地区初春与盛夏MCC结构特征比较分析[J].高原气象,2017,36(6):1638-1654.
[7]高帆,张永婧,李瑞,等.2015年8月3日山东西北部暴雨过程的中尺度特征分析[J].海洋气象学报,2017,37(2):96-101.
[8]赵桂香,薄燕青,邱贵强,等.黄河中游一次大暴雨的观测分析与数值模拟[J].高原气象,2017,36(2):436-454.
[9]黄治勇,谌伟,张文,等.长江中下游深秋季节一次MCC过程的成因[J].长江流域资源与环境,2012,21(8):1025-1031.
[10]侯淑梅,孙鹏程,杨璐瑛,等.环境场条件对雷暴传播运动影响实例分析[J].海洋气象学报,2018,38(4):58-70.
[11]杨忠明,吴浙红,王兴菊.贵州中南部2次MCC致洪暴雨的综合分析[J].干旱气象,2013,31(2):362-372.
[12]杨晓霞.副热带高压边缘连续两次强降水形成机制分析[J].海洋气象学报,2017,37(3):62-72.
[13]张立祥,李泽椿.一次东北冷涡MCS边界层特征数值模拟分析[J].气象学报,2009,67(1):75-82.
[14]朱义青,郭宝阳,王玉亮,等.一次低槽冷锋暴雨数值模拟和诊断分析[J].山东气象,2016,36(3):13-19.
[15]赵桂香,赵建峰,杨东,等.山西一次大暴雨过程云图及环境场的特征分析[J].高原气象,2013,32(6):1747-1757.
[16]井喜,屠妮妮,井宇,等.中国MCC时空分布与天气学特征分析[J].高原气象,2013,32(6):1597-1607.
[17]MADDOX R A.Mesoscale convective complexes[J].Bull Ameteor Soc,1980,61(11):1374-1387.
[18]MADDOX R A.Large-scale meteorological conditions associated with mid-latitude mesoscale convective complexes[J].Mon Wea Rev,1983,111(7):1475-1493.
[19]高守亭,孙建华,崔晓鹏.暴雨中尺度系统数值模拟与动力诊断研究[J].大气科学,2008,32(4):854-866.
[20]冉令坤,齐彦斌,郝寿昌.“7.21”暴雨过程动力因子分析和预报研究[J].大气科学,2014,38(1):83-100.
[21]ROMERO R C,DOSWELL C AⅢ,RIOSALIDO R.Observations and fine-grid simulation of a convective outbreak in northeastern Spain:Importance of diurnal forcing and convective cold pools[J].Mon Wea Rev,2001,129(9):2157-2182.
[22]肖现,陈明轩,高峰,等.弱天气系统强迫下北京地区对流下山演变的热动力机制[J].大气科学,2015,39(1):100-124.