Dr Yongkang Xue studies land surface modeling, land/atmosphere interactions, climate change, regional climate downscaling, and remote sensing. He has been instrumental in the development of the "SSiB" land surface scheme, which has been coupled with a number of GCMs and regional models. Using coupled land-surface/atmosphere models, he has conducted numerous sensitivity and prediction studies to investigate the impact of land-surface processes, including vegetation biophysical processes, land-cover and land use change, and land-surface parameters and parameterizations, on regional climate and global climate variability and anomalies, with a special emphasis on monsoon systems, and the mechanism involved. He also works on the remote sensing methodology for atmospheric and land surface variables. He has developed a number of undergraduate and graduate courses for land surface modeling, climate and environment change, and remote sensing studies. 

摘    要： 

Land-climate interactions play a key role in the climate system. The land’s role in the climate system has been the subject of much recent exploratory research. However, the biophysical, biogeochemical, hydrological, meteorological, ecosystem processes, and the boundary-layer processes that underlie the connections between climate and vegetation, terrestrial carbon processes, soil moisture and temperature are not yet fully understood, and are investigated separately in many studies. It is important to integrate these processes and fully understand their roles and interaction in climate variability and anomaly, and climate changes.   

Two issues will be presented in this talk.(1)Two-way fully coupled land models have been widely introduced to the climate change studies, e.g., in CMIP5.  However, it remained a challenge to apply appropriate constrains in integrated biophysical and biogeochemical modelling approach on regional vegetation dynamics and climate variability at seasonal-decadal scales. The CMIP5 simulations show serious problem in this aspects. In this part, we will present two constrains necessary in exploring these multiple processes interactions at seasonal to decadal scales. In the biophysical process research, the water and energy balance approach has been proved to be successful in GEWEX researches and carbon conservation is also successfully applied to biogeochemical research, application of these three conservations in a fully coupled terrestrial earth system is challenging. We will discuss a few issues related to the importance of conservations. Meanwhile, satellite data is the only crucial source for global validation.(2)Despite recent progress in Earth System Modeling, proper simulating the regional decadal variability remains a great challenge. Most stat-of-the-art Earth Model systems fail to reproduce the last century’s most severe drought in the 1980s in the Sahel. It is a great challenge to understand the impact of external forcings: oceans, land, and aerosols, on East Asian monsoon variability. Our new NSF Earth System Modeling East Asian climate project takes interdisciplinary approach, in which the role of Tibetan forcing in the East Asian and global atmosphere and ocean is one of the major subject and the Institute of the Tibetan Plateau Research is a key collaborator.