A SIMPLE LAND SURFACE PROCESS MODEL FOR USE IN CLIMATE STUDY

A quantitative description of the processes taking place among the atmosphere, vegetation and soil is needed for studying air-land interaction and interrelation between the geosphere and the biosphere. In this paper, a simple land surface process model is proposed. Through transfers and exchanges of heat and water, the therrnal and moisture states of the atmosphere, vegetation and soil are linked in a coupled system, in which vegetation is considered as a horizontally uniform layer, soil is divided into three layers and the horizontal differences of variables in the system are neglected. The preliminary results of the experiment indicate that the model is capable of predicting the thermal and moisture conditions of the land surface and suitable to climate study.

Influences of agricultural phenology dynamic on land surface biophysical process and climate feedback

Response and feedback of land surface research priorities in the field of geoscience. The process to climate change is one of the current study paid more attention to the impacts of global change on land surface process, but the feedback of land surface process to climate change has been poorly understood. It is becoming more and more meaningful under the framework of Earth system science to understand systematically the relationships between agricultural phenology dynamic and biophysical process, as well as the feedback on climate. In this paper, we summarized the research progress in this field, including the fact of agricultural phenology change, parameterization of phenology dynamic in land surface progress model, the influence of agricultural phenology dynamic on biophysical process, as well as its feedback on climate. The results showed that the agriculture phenophase, represented by the key phenological phases such as sowing, flowering and maturity, had shifted significantly due to the impacts of climate change and agronomic management. The digital expressions of land surface dynamic process, as well as the biophysical process and atmospheric process, were improved by coupling phenology dynamic in land surface model. The agricultural phenology dynamic had influenced net radiation, latent heat, sensible heat, albedo, temperature, precipitation, circulation, playing an important role in the surface energy partitioning and climate feedback. Considering the importance of agricultural phenology dynamic in land surface biophysical process and climate feedback, the following research priorities should be stressed： （1） the interactions between climate change and land surface phenology dynamic; （2） the relations between agricultural phenology dynamic and land surface reflectivity at different spectrums; （3） the contributions of crop physiology characteristic changes to land surface biophysical process; （4） the regional differences of climate feedbacks from phenology dynamic in different climate zones. This review is helpful to accelerate understanding of the role of agricultural phenology dynamic in land surface process and climate feedback.