国家自然科学基金No.41301339;湖南省重点学科项目地理学No.201201;湖南省高校科技创新团队;湖南省高校创新平台开放基金No.14K056;湖南省自然科学基金No.13JJ4044 Supported by the National Natural Science Foundation of China No.41301339,the Construct Program of the Key Discipline in Hunan Province China No.201201,the Aid Program for Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province,the Scientific Research Fund of Hunan Provincial Education Department No.14K056 and the Natural Science Foundation of Hunan ProvinceNo.13JJ4044