地膜覆盖农田的地气相互作用特征的观测研究及其参数化

Land atmosphere interaction plays an important part in the earth system. So it is essential to improve the ability about climatic prediction that the exchange of substance and energy between land and atmosphere is described accurately. Accordingly it is one of the hot and hard problems about the global climate change that the impact of land use and cover change on environment and climate. At present, the technology of plastic mulch cover is applied extensively in farming industry. There are two kinds of plastic mulch cover mainly, one is the soil covered by plastic mulch closely; the other is greenhouse. The plastic mulch is very much different from soil. When the soil covered by plastic mulch, the land atmosphere interaction will be changed by two ways: the property of the underlying surface is changed in one hand, such as the albedo becomes bigger; in the other hand, the water vapor exchange between land and atmosphere is prevented by the plastic mulch. Fore the land atmosphere interaction is changed evidently, this must product effect on the environment climate in some way. Up to now, the impact of plastic mulch cover is not researched well. So the project is going to study on the interaction of atmosphere-vegetation-platic mulch-soil, and to aim at: (1) reveal the characteristics of land atmosphere interaction over farmland cover by plastic mulch; (2) develop the parameterization and land surface process model that can describe the interaction of atmosphere-vegetation-platic mulch-soil.

地气相互作用是地球科学系统的重要组成部分。准确刻画地气间能量和物质交换过程对于提高气候预测水平至关重要。与此相应，人类活动引起的土地利用/土地覆盖改变对环境气候影响是全球气候变化研究的热点和难点问题之一。目前，塑料薄膜覆盖技术在农业生产中被广泛应用-主要有直接贴地覆盖和蔬菜大棚两种形式。塑料薄膜明显区别于土壤，故而它一方面改变土壤物理属性，比如增加反照率等；另一方面人为阻碍了土壤与大气间水汽交换。塑料薄膜覆盖农田显著地改变了地气相互作用，必定会对环境气候产生影响。塑料薄膜覆盖农田作用尚未得到充分研究，本项目针对大气-植被-塑料薄膜-土壤相互作用进行观测研究，预期目标：（1）揭示塑料薄膜覆盖农田的地气相互作用特征；（2）发展能刻画大气-植被-塑料薄膜-土壤相互作用的参数化方案和陆面过程模式。

塑料薄膜覆盖技术在农业生产中被广泛应用-主要有直接贴地覆盖和蔬菜大棚两种形式。塑料薄膜明显区别于土壤，故而它一方面改变土壤物理属性，比如增加反照率等；另一方面人为阻碍了土壤与大气间水汽交换。塑料薄膜覆盖农田显著地改变了地气相互作用，必定会对环境气候产生影响。本项目针对大气-植被-塑料薄膜-土壤相互作用，分别在干旱区地膜覆盖农田下垫面和山东蔬菜温棚区进行观测研究。通过实验手段，分析观测结果和理论研究，揭示塑料薄膜与其覆盖的地表层之间能量和物质的交换过程，以及塑料膜内外能量和物质的交换过程，深入分析了塑料薄膜覆盖农田和温室大棚的地气相互作用特征。从塑料薄膜的物理属性出发，提出了四点假设，核心思想为地膜覆盖完全切断了土壤与大气间的水汽输送，阻断了大气与土壤呼吸产生CO2的交换，进而分别建立了地表层、地膜层和土壤层的能量平衡方程，提出了地膜层辐射传输和感热输送参数化方案，便得到一个描述地膜层物理过程的子模型。进一步通过对一些关键物理过程和参数化进行建模和参数化，发展了地膜覆盖下垫面的新的陆面过程模式。