报告题目：Assessing aerosol indirect effects in a global climate model using short hindcast ensembles

　　报告地点：LAPC多功能厅

　　报告时间：2017年9月20日，下午15:00

　　报告专家：张恺 研究员，

　　Pacific Northwest National Laboratory

　　报告摘要：Quantifying and attributing the anthropogenic aerosol indirect effect in global aerosol-climate models is a very difficult task. Process interactions lead to nonlinear variabilities in the atmospheric states (e.g. cloud cover), causing noise that can hinder signal detection between the simulations with pre-industrial and present-day emissions. Consequently, estimating the anthropogenic aerosol indirect effect in a global aerosol-climate model typically requires very long simulations to get statistically robust results, especially for regional features. In this talk, I will introduce a new modeling strategy to estimate the anthropogenic aerosol indirect effect at shorter time scales. Ensemble hindcast simulations are performed using the Community Atmosphere Model (CAM5) with both pre-industrial and present-day emissions, each running for a few days with a small random perturbation to the initial condition. Results show the method can effectively detect the anthropogenic aerosol effect on cloud and radiation. It can further estimate the uncertainty caused by the chaotic response to small perturbations in the atmospheric state. The method is particularly useful for estimating the anthropogenic aerosol effect in high-resolution, costly, and complex climate models.

　　简介：

　　张恺，美国能源部太平洋西北国家实验室三级研究员。主要研究方向为大气模式中气溶胶和冰云的参数化，气溶胶对天气和气候的潜在影响，以及高分辨率大气模式中水和能量循环的模拟和检验。2004-2008年在大气物理所学习，研究方向为LASG格点大气模式中气溶胶模式的发展。2006-2007参加中科院-马普协会联合培养项目，国家公派在德国马普气象研究所学习。2008-2011年在德国马普气象研究所做博士后研究，作为主要完成人发展了全球气溶胶-气候模式ECHAM-HAM 第二版，模式被广泛应用于气溶胶的气候效应研究。2011年至今，在美国能源部太平洋西北国家实验室工作，目前主要从事美国能源部地球系统模式中云和气溶胶参数化方案的改进，以及云和气溶胶对水和能量循环影响的研究。详细信息：http://www.pnnl.gov/science/staff/staff_info.asp?staff_num=7659