Toward Eliminating the Double Inter-Tropical Convergence Zone and Improving El Nino/Southern Oscillation Simulation in the NCAR Community Climate System Model Version 3 (CCSM3)

这是一个延续项目，其重点是减轻双热带辐合带（ITCZ）问题，并改进NCAR社区气候系统模式CCSM3对厄尔尼诺和南方涛动（ENSO）的模拟。这些都是CCSM3中最根本的缺陷。使用的基本研究工具是CCSM3和改进的Zhang-McFarlane对流格式。将分析耦合模式与改进对流方案的整合，以检验ITCZ和ENSO模拟的改进。为了了解对流与大尺度环流的相互作用，以及对流参数化在消除双ITCZ中的作用，将对原始对流方案和改进对流方案进行短期（=10年）数值试验。ENSO模拟将重点关注赤道地区纬向风应力在改善太平洋对流模拟中的作用，以及增强的马登-朱利安涛动（MJO）变率在增加模拟ENSO周期的周期性中的作用。知识价值：PI将(1)改进对ITCZ降水的模拟，以消除CCSM3的双ITCZ问题；(2)通过精心设计的数值实验，提高对对流参数化在双ITCZ问题中的作用的科学认识；(3)改进ENSO周期性的模拟；(4)找到改进的原因，特别是地面风应力和增强的MJO模拟在CCSM3中的作用。这项工作的完成将提供新的见解：(1)新的积云对流参数化将导致ITCZ模拟的改进，以及(2)导致ccsm3中最基本模式缺陷的缓解过程。更广泛的影响：该研究将导致一个改进的气候系统模式，该模式正在全球范围内被气候研究界用于广泛的气候变化研究。它还为研究生提供学习经验和培训。

This is a continuation project with a focus on mitigating the double Inter-Tropical Convergence Zone (ITCZ) problem and to improve the simulation of El Nino and Southern Oscillation (ENSO) in the fully coupled NCAR Community Climate System Model, CCSM3. These are amongst the most fundamental deficiencies in CCSM3. The basic research tools used are the CCSM3 and the improved Zhang-McFarlane convection scheme. The coupled model integrations with improved convection scheme will be analyzed to examine the improvement of ITCZ and ENSO simulations. Short term (=10 years) numerical experiments with both the original and improved convection scheme will be conducted to understand the interaction between convection and the large-scale circulation, and the role of convection parameterization in the elimination of double ITCZ. The ENSO simulation will focus on the role of the zonal wind stress off the equatorial region in relation to the improved simulation of convection in the Pacific and the role of enhanced Madden-Julian Oscillation (MJO) variability in increasing the periodicity of the simulated ENSO cycle. Intellectual merit: The PI will (1) Improve the simulation of the ITCZ precipitation to eliminate the double ITCZ problem in CCSM3, (2) Improve scientific understanding of the role of convection parameterization in the double ITCZ problem through carefully designed numerical experiments, (3) Improve the simulation of ENSO periodicity, and (4) Find the causes of the improvements, in particular, the roles of surface wind stress and enhanced MJO simulation in the CCSM3. Completion of this work will offer new insights into: (1) Ways the new cumulus convection parameterization will result in an improved simulation of ITCZ, and (2) Processes that results in the mitigation of the most fundamental model deficiencies in CCSM3Broader impacts: The research will lead to an improved climate system model that is being used worldwide by the climate research communities for a wide spectrum of climate change research. It also provides learning experiences and training for a graduate student.