大涡模式对青藏高原复杂下垫面能量水汽垂直输送特征的模拟分析

The accurate understanding of energy and water exchange between the land surface and the atmosphere is the key to analyzing the profound influence of the Tibet Plateau on the regional and global climate. But the uncertainty of land-atmospheric interactions over complex surfaces is one of the important sources of errors for the climate models and meteorological models. In this proposal, the processes and underlying mechanisms of energy and water vertical transport over complex surfaces in Tibetan Plateau will be simulated and analyzed using large eddy simulations (WRF_LES), combined with the field measurements in the Nagqu Station for Plateau Climate and Environment, Chinese Academy of Sciences. First, the characteristics of secondary circulations and the influence on surface fluxes will be analyzed based on the simulated spatiotemporal evolutions of the wind, temperature and water vapor in the atmospheric boundary layer (ABL) over complex surfaces with prescribed different heterogeneities in the Tibetan Plateau using the WRF_LES. Second, the influence of complex surfaces on the formation and development of convective clouds will be investigated based on the simulated spatiotemporal evolutions of temperature and water vapor from the ABL top to the top layer of the simulation. The influence of the complex surfaces on the transition from shallow convective clouds to deep convective clouds will be given special attention. Third, the capability of WRF mesoscale models (WRF_meso) in simulating the energy and water exchanges in the ABL and the formation and development of convective clouds over complex surfaces in Tibetan Plateau will be analyzed by comparing the simulated spatiotemporal evolutions of winds, temperature and water, and the key variables from the WRF_LES and WRF_meso. This proposal will benefit our understanding of the land-atmospheric interactions over complex surfaces in Tibetan Plateau and the improvement of the schemes for the ABL, microphysics and convective clouds in meteorological models and climate models.

青藏高原复杂下垫面的地气相互作用是理解它对区域至全球气候显著影响的关键。本研究利用大涡模式（WRF_LES）模拟分析中科院那曲高寒气候环境观测站所在区域的复杂下垫面对边界层能量水分输送和对积云形成与发展的影响。首先，基于大涡模式模拟的大气边界层内风速、位温、水汽时空演变数据，分析复杂下垫面引起的次级环流的结构特征及其对边界层结构和对能量水分的影响。其次，基于大涡模式模拟的从边界层顶至模拟顶层的风、气温和水汽的时空演变数据，分析复杂下垫面对积云形成与发展的影响，特别是复杂下垫面对浅层对流云向深层对流云转变过程的影响。最后，基于WRF_LES分析结果，利用对比分析的方法分析WRF中尺度模式（WRF_meso）对复杂下垫面对边界层内地气间能量水分交换过程以及积云形成和浅层对流云向深层对流云转过的过程模拟能力。这一研究工作有助于加深对复杂下垫面能量水汽交换与相关参数化方案模拟能力的认识。

按照青年基金项目书，综合利用青藏高原那曲站站点观测数据、数值模式结果和再分析数据从青藏高原局地地气耦合的角度讨论了青藏高原复杂下垫面能量水器垂直输送过程与特征的研究。具体研究内容简述如下: .1. 利用那曲站BJ观测点的站点观测数据和ERA5数据讨论分析BJ观测点不同天气条件下地表与边界层顶的热量与水汽收支特征.2.利用BJ观测站点观测结果和WRF模式讨论分析在晴天有云条件下在地表与边界层顶热量水汽收支以及对流云形成与土壤湿度的关系.3.利用2014年在纳木错、珠峰两个站的站点观测数据、无线电探空数据与再分析数据ERA5探讨青藏高原雨季和干季时在地表与边界层顶的能量水汽收支的季节变化特征及其影响因素.4. 利用再分析数据ERA5和站点观测数据,讨论分析青藏高原雨季和干季时地表与边界层顶能量水汽收支的季节差异和空间分布及其主要影响因素.在项目的支持下，我以第一作者身份发表SCI论文三篇，合作发表论文两篇。在此基础上，我将研究问题进一步深化，在此基础上参加了青藏高原第二次综合科学考察项目，申请并获批了国家自然基金委面上项目（资助编号：42175085）。