IAP近期际气候预测系统海洋初始化试验中海表温度和层积云的关系  

The Simulation of Stratocumulus and Its Impacts on SST:Based on the IAP Near-Term Climate Prediction System

作　　者：郭准[1,2] 周天军[1,3] Guo Zhun Zhou Tianjun(LASG, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China Climate Change Research center, Chinese Academy of Sciences, Beijing 100029, China University of Chinese Academy of Sciences, Beijing 100029, China)

机构地区：[1]中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室,北京100029 [2]中国科学院气候变化研究中心,北京100029 [3]中国科学院大学,北京100049

出　　处：《地球科学进展》2017年第4期373-381,共9页Advances in Earth Science

基　　金：公益性行业(气象)科研专项项目"基于FGOALS-s;CMA和CESM气候系统模式的年代际集合预测系统的建立与研究"(编号:GYHY201506012);国家自然科学基金青年科学基金项目"云辐射反馈过程对东亚-西北太平洋地区海气相互作用的影响及其气候模式模拟的不确定性"(编号:41405103)资助~~

摘　　要：气候预测系统的海洋初始化积分试验考虑了海气相互作用,可以视为一种弱耦合同化试验。海温(SST)和层积云的关系是检验海气相互作用过程模拟效果的重要参考。分析了基于耦合气候系统模式FGOALS-s2的中国科学院大气物理研究所近期气候预测系统IAP Dec Pre S的海洋初始化模拟实验(简称EnOI-IAU试验)所模拟的海温—云关系。结果表明,EnOI-IAU试验较好地模拟出了SST和低云的气候态空间分布,但在主要层积云区低估了低云云量和云水,SST模拟偏高,特别在副热带东大洋沿岸和南大洋。部分原因是这些地区实际影响海表温度模拟的是模式的内部过程,而低云模拟不足导致了海表入射更多的短波辐射(强度约偏强20 W/m^2),迫使局地SST模拟过高。分析显示,低云模拟不足主要是由于EnOI-IAU试验不能再现合理的边界层逆温结构,表现为大气垂直速度、温度和湿度过于集中在近地层,使得边界层垂直热输送较弱、边界层无法充分混合,进而无法有效模拟出层积云。这些结果表明,未来引入大气观测数据同化,特别是改善边界层结构的模拟,对形成完整的耦合同化系统具有必要性。Abstract： The near-term climate prediction system （DecPreS） is built on the initialization of the ocean state,which can be regarded as a full-coupled system with ＂adjusted＂ air-sea interactions. The relationship between stratocumulus and Sea Surface Temperature （ SST ） is an essential part of air-sea interactions. In this study, we investigated such a relationship in DecPreS of the Institute of Atmospheric Physics, in which the merge of the Ensemble Optimal Interpolation （EnOI） and Incremental Analysis Update （IAU） scheme was employed. EnOI-IAU generally reproduces the spatial pattern of SST and low-clouds. However, the simulated cloud fraction/liquid water path are underestimated while the SST is overestimated in stratocumulus regimes, especially in the subtropical East Pacific and South Ocean. It is partly because the unrealistic air-sea interaction dominates these regions that the underestimated stratocumulus allows more input of incoming shortwave flux （20 W/m2）. The deficient stratocumulus is highly related to the unrealistic vertical structure of Atmospheric Boundary Layer （ABL）, in which the moisture, temperature and vertical heat transports concentrate at the surface layer. Our results imply that stratocumulus and ABL be important in DecPreS. Clarifying the importance of ABL and stratocumulus will provide a possible way to improve the DecPreS.

关 键 词：初始化试验 耦合气候系统模式 海表温度 层积云 大气边界层 

分 类 号：P426.5[天文地球—大气科学及气象学] P731.11