东海黑潮暖水区一次夜间云覆盖边界层发展过程的大涡模拟——辐射强迫研究  

Large-Eddy Simulation of Nocturnal Cloud-Topped Boundary Layer over the Warm Side of the East China Sea Kuroshio:A Radiative Forcing Study

作　　者：郭九华 张苏平[1] 衣立[1] 刘敬武[1] GUO Jiu-Hua;ZHANG Su-Ping;YI Li;LIU Jing-Wu(The Key Laboratory of Physical Oceanography,Ministry of Education,Ocean-Atmosphere Interaction and Climate Laboratory,Ocean University of China,Qingdao 266100,China;Taizhou Meteorological Bureau,Taizhou 318000,China)

机构地区：[1]中国海洋大学物理海洋教育部重点实验室海洋-大气相互作用和气候实验室,山东青岛266100 [2]台州市气象局,浙江台州318000

出　　处：《中国海洋大学学报（自然科学版）》2018年第7期1-9,共9页Periodical of Ocean University of China

基　　金：国家重大科学研究项目(2012CB955600);自然科学基金项目(41175006);国家自然科学基金委员会-山东省人民政府联合资助海洋科学研究中心项目(U1406401);中央高校基本科研业务费专项(201564012)资助~~

摘　　要：2015年4月2日,中国海洋大学东方红2船在东海黑潮暖水区观测到了一次夜间云顶逆温边界层发展的过程。本文利用船载数据及UCLA_LES3.0模式进行数值模拟,讨论边界层发展的原因以及云对边界层发展的作用。结果显示,海表潜热通量的供应使边界层内水汽增多,水汽抬升凝结成云。云的产生使边界层内水汽通量、热通量以及垂向湍流速度的分布发生改变,云区的水汽通量变大,云顶的热通量发生突变,云区和近表面层均有湍流速度的极大值,云底有湍流速度的极小值。云形成过程中通过改变边界层内浮力项的贡献影响边界层的垂直结构,云区有正的浮力项贡献,云底以下有负的浮力项贡献。云顶长波辐射主要影响边界层中上层,在关闭辐射强迫后,边界层内比湿和位温的廓线没有明显变化,但最大垂直速度减小了20%,垂向积分的湍流动能降低了约30%,垂向湍流速度在边界层中上层不存在极大值,边界层内热通量廓线没有突变,水汽通量和热通量廓线分布与晴空边界层廓线相当。本研究通过数值试验证明了云顶长波辐射效应对大气边界层的反馈作用,为理解云与边界层的相互作用提供了科学依据。A research vessel(R/V)Dongfanghong 2 of Ocean University of China captured a rapid development of cloud-topped boundary layer when it across the warm side of the East China Sea Kuroshionon 02 April,2015.The UCLA_LES3.0 model are used for numerical simulation to discuss the reasons for the development of the boundary layer and the effect of the cloud on the development of the boundary layer.Simulated boundary layer growth is forced by surface heat flux and a combination of radiative cooling and entrainment at the top of boundary layer.The water vapor condenses and releases latent heat during the rising process to form cloud.The generation of cloud changes the distribution of water vapor flux and heat flux in the boundary layer,which is manifested in the large amount of water vapor flux in the cloud layer,and the heat flux has a mutated value at cloud top due to the radiation cooling and the entrainment between cloud top and free atmosphere.In addition,the formation of the cloud can change the vertical structure of the boundary layer by changing the contribution of the buoyancy term of turbulence kinetic energy in the boundary layer,which denote the positive buoyancy contribution in the cloud layer,and the negative buoyancy contribution below the cloud base.The influence of radiation is relatively large during the upper boundary layer,which is mainly reflected in the distribution and flux of the vertical turbulent velocity.Since there is no long-wave radiative cooling,the water vapor flux and heat flux decrease obviously and there is no maximum value of the vertical turbulent velocity in the upper boundary layer,which is quite similar to that of the clear sky boundary layer.In this study,we prove the feedback effect of the cloud on the atmospheric boundary layer,and provide an important scientific basis for understanding the interaction between the cloud and the boundary layer.

关 键 词：海洋大气边界层 大涡模拟 湍流动能 水汽通量 

分 类 号：P426.53[天文地球—大气科学及气象学]