科尔沁沙地典型生态系统水热通量传输机理及其与植被耦合关系试验和模拟研究

The grassland desertification in semi-arid region is one of the most important ecological problems of China. Even though studies show that overgrazing, irrational agricultural reclamation and climate change is the main cause of desertification, but one of the basic researches which has closely related to desertification process is still unclearly. The research is water heat flux transfer process and it coupling mechanism with vegetation in sandy land. In this project the Horqin sandy land well be selected as the study area, which is the typical sandy land in semiarid area of China.The sand dunes and inter-dune meadow are selected as the research object for they are both the typical ecosystem of Horqin sandy land. The micrometeorology, eddy covariance, and remote sensing technology were used as observation technologies. Field test, data analysis, and remote sensing retrieval are combined as research methods. With these methodologies the water and heat fluxes transmission mechanism between interfaces of soil and atmosphere will be study in the dunes and inter-dune meadow ecosystem. The coupling effect relationship of energy fluxes with evapotranspiration, condensation water, groundwater level and phreatic evaporation will be research too. Then, a sandy land water and heat fluxes estimation model will be developed build based on the remote sensing data in order to research the distribution and temporal variation, and reveal the coupling relationship between the water and heat fluxes with ecosystem of dunes and inter-dune meadow. This study will rich and perfect the theory and techniques of sandy ecohydrology study, reveal sandy hydrothermal coupling associated relationship and flow mechanism has important practical significance for the sustainable maintenance of the ecosystem of Saudi degraded ecosystems restoration and reconstruction to provide a theoretical basis and technical support.This study will reveal the water heat coupling associated relationship and transmission mechanisms in sandy land. The study results will not only rich and perfect ecohydrology theory and technology in sandy land but they also provide theoretical and scientific bases for preserving natural sandy land ecosystems, and restoring degraded ecosystems in sandy land.

半旱区草原沙化是我国最主要的生态问题之一，尽管研究表明过渡放牧、不合理的农垦和气候变化是沙化的主要原因，但与沙化过程密切相关沙地水热通量传输过程及其与植被生态间的耦合作用机理仍不明确。本项目以我国半干旱区典型沙地——科尔沁沙地为研究区，选取其典型生态系统沙丘和丘间草甸为研究对象，通过微气象、涡度相关和遥感技术，采用野外试验、数据分析和遥感反演相结合的研究方法。以研究水热通量在沙丘和丘间草甸地气界面间的传输机理；分析能量通量与蒸散发、土壤水分、地下水位和潜水蒸发间的耦合作用关系；并通过构建基于遥感的水热通量估算模型来揭示沙丘和丘间草甸生态系统水热通量分布特征和时空变化规律，最终结合遥感植被特征参数探讨水热通量与植被间的耦合关系。本研究将揭示沙地水热耦合伴生关系与运移机制，明确水热通量和各能量分量与植被间耦合关系，对丰富完善沙地生态水文学理论有重要意义，也可为退化生态系统恢复重建提供科学依据。

半旱区草原沙化是我国最主要的生态问题之一。沙地是草原沙化的产物，尽管研究表明过渡放牧、不合理的农恳和气候变化是引起沙化的主要原因，但与沙化过程密切相关的基础研究内容之一，沙地水热通量传输过程及其与植被生态间的耦合作用机理仍不明确。本研究以我国半干旱区典型沙地——科尔沁沙地为研究区，选取其典型生态系统沙丘和丘间草甸为研究对象，采用野外试验、数据分析和遥感反演相结合的研究方法，得到了研究区水热通量在沙丘和丘间草甸的分布特征和传输机理，分析了蒸散发与能量通量和土壤水分间的耦合作用关系；并利用基于遥感的沙地水热通量估算模型估算了研究区不同尺度的水热通量和植被生态系统间的耦合作用关系。.通过本项目的实施，取得了如下研究成果：.（1）、获得了研究区沙丘和丘间草甸地实验点2013-2018年的涡度相关通、气象、土壤、植被等的联系观测数据集（持续观测中），获得了研究区科尔沁沙地多年的区域遥感数据以及反演的区域能量和蒸散发数据，整合以上数据建立了研究区水热通量和遥感数据集；.（2）、通过对SEBAL、METRIC和MEP不同遥感蒸散发估算模型的对比分析，总结探讨了适合沙地的水热通量遥感估算模型；.（3）、在本项目的支持下共发表研究论文14篇，其中项目负责人第一或通讯作者论文13篇，SCI收录论文4篇，EI收录论文2篇，申请发明专利2项；.（4）、项目执行期间培养硕士研究生5名，2名毕业、3名在读，1人次获得国家奖学金，2人获得内蒙古自治区奖学金，1人获得内蒙古自治区优秀硕士毕业生称号，15名本科生通过本项目完成本科毕业论文，项目组2人晋升为副高职称，1人晋升中级职称，1人获得中科院“西部之光”青年学者A类称号，1人获内蒙古“草原英才”称号，1人获“草原英才”青年创新人才一层次，1人获内蒙古“杰出青年”培育基金支持；.（5）、项目执行期间项目组成员多次参加相关学术会议，同时邀请国内外学者赴研究区考察并及学术交流。.综上所述，在项目执行期间，全面完成计划任务书规定的研究内容及各项考核指标。