| 我国东南沿岸及复杂山地后汛期降水日变化的数值研究 |
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| 引用本文： | 赵玉春,王叶红.我国东南沿岸及复杂山地后汛期降水日变化的数值研究[J].大气科学,2020,44(2):371-389. |
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| 作者姓名： | 赵玉春 王叶红 |
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| 作者单位： | 1.厦门市气象局海峡气象开放实验室, 厦门 361012;中国气象科学研究院灾害天气国家重点实验室, 北京 100081;福建省灾害天气重点实验室, 福州 350001 |
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| 基金项目： | 国家自然科学基金项目41675047、41075038，中国气象科学研究院灾害天气国家重点实验室开放课题2018LASW-B01，厦门市科技惠民计划项目3502Z20174052 |
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| 摘 要： | 利用2009~2017年7~9月福建省逐小时地面加密自动站资料和2015~2017年7~9月厦门站的探空资料,通过K均值聚类法和中尺度数值模式(WRF3.9.1.1版本)理想数值模拟,分析了我国东南沿岸及复杂山地(福建)后汛期降水日变化特征,揭示了地形热力环流以及海陆风环流在热对流降水日变化形成中的作用,探讨了环境温湿廓线及风垂直廓线对热对流降水日峰值强度和日峰值出现时间的影响。结果发现:我国东南沿岸复杂山地(福建)后汛期降水日变化受地形热力环流和海陆风环流的影响和调制,白天辐射加热在复杂山地形成的局地热力环流激发出对流降雨带,午后受海风环流的影响,对流降雨带组织发展达到峰值,之后随着地形热力环流和海风环流减弱雨带逐渐减弱。武夷山及周边复杂山地的降水日变化主要受地形热力环流的影响,在午后对流降水达到峰值,夜间减弱几近消失。理想数值试验进一步证实了我国东南沿岸复杂山地地形热力环流对对流降雨的触发以及海陆风环流在山地对流雨带组织发展中的作用,环境温湿廓线以及风垂直廓线对热对流降水日峰值强度以及日峰值出现的时间具有重要影响,其中环境温湿廓线的大气抬升凝结高度、大气可降水量、大气的对流不稳定度以及大气中低层湿度分布的不同,会影响热对流降水日峰值强度,并通过影响山地热力对流触发时间,改变热对流降水日峰值时间,而环境风垂直廓线的低层气流强度和方向、中低层垂直风切变的不同,会影响地形热力对流系统的启动、组织发展和移动等特征,进而影响热对流降水日峰值强度以及热对流降水日峰值时间。
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| 关 键 词： | 地形影响 海陆风 热对流降水 日变化 |
| 收稿时间： | 2018/12/4 0:00:00 |
A Numerical Study of the Diurnal Variations in Second Rainy Season Rainfall in the Coastal and Mixed Topographical Regions of Southeast China |
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| ZHAO Yuchun and WANG Yehong.A Numerical Study of the Diurnal Variations in Second Rainy Season Rainfall in the Coastal and Mixed Topographical Regions of Southeast China[J].Chinese Journal of Atmospheric Sciences,2020,44(2):371-389. |
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| Authors: | ZHAO Yuchun and WANG Yehong |
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| Institution: | 1.Laboratory of Straits Meteorology, Xiamen Meteorological Bureau, Xiamen 361012;State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Science, Beijing 100081;Fujian Key Laboratory of Severe Weather, Fuzhou 3500012.Laboratory of Straits Meteorology, Xiamen Meteorological Bureau, Xiamen 361012;Fujian Key Laboratory of Severe Weather, Fuzhou 350001 |
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| Abstract: | In this paper, diurnal rainfall variations in the second rainy season in the coastal and mixed topographical regions of Southeast China (Fujian) were analyzed. The roles of topographical thermal circulations and land-sea breezes in the diurnal variations in thermal convective rainfall were investigated. The impacts of environmental temperature, moisture, and vertical wind profile on the time and intensity of diurnal peaks of convective rainfall were examined using hourly surface data from the automated weather station of Fujian province for the periods July to September of 2009-2017. With radio-soundings at Xiamen station for the periods July to September of 2015-2017 and K-mean clustering methodology, idealized numerical simulations were conducted using a mesoscale numerical model (WRF3.9.1.1). Results were as follows: diurnal rainfall variations for the second rainy season in the study regions of Southeast China (Fujian) were impacted and regulated by topographical thermal circulation and land-sea breezes. The topographical thermal circulation due to daytime heating initiated convective rainfall bands. The bands were organized and peaked during the afternoon sea breezes, then gradually weakened with the weakening topographical thermal circulation and sea breeze. Idealized numerical experiments further proved the role of topographical thermal circulation and sea breezes in the convective rainfall initiation and organization. Environmental temperature, moisture, and vertical wind profiles exerted an important impact on the diurnal peak intensity and time of occurrence of the convective rainfall. The atmospheric lifting condensation level, precipitable water, convective instability, and differential distribution of moisture at the mid-lower levels impacted the diurnal peak intensity of the convective rainfall and changed its time of occurrence through altering its time of initiation. Differences in low-level wind intensity and direction and vertical shear at the mid-lower levels impacted the initiation, organization, and movement of the topographical convection, and further impacted its diurnal peak intensity and time of occurrence. |
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| Keywords: | Topographical effects Land-sea breeze Thermal convection precipitation Diurnal variation |
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