【摘要】 小冰期是数千年来最引人注目的一个冷期，也是近百年变暖的直接历史背景，该时期我国农业扩展范围已与现代相差无几。自然植被被农业植被替换， 对区域水循环和气候变化都产生影响。比较冷暖时期该类影响之差别，有利于认识土地覆盖与气候的联系。文中利用全球和区域气候模式， 考察小冰期和现代两种全球背景下我国区域土地覆盖变化对七月平均气候状况的影响。结果表明：小冰期夏季偏冷地区主要在北方，农业具有减缓小冰期大尺度降温的效应，而在较温暖且温度变化较小的华南和华中地区，农业则起一定的降温效应；农业对现代气候下的降水影响不大，但在小冰期背景下却导致降水减少更多还原

【Abstract】 Agriculture changes natural vegetation and therefore water and energy exchanges between land and atmosphere.This may cause different impacts on regional climates,depending on the different climates themselves.We compare the impacts of agriculture on July climate between the Little Ice Age(LIA)and the present warm period through numerical modeling with global and regional climate models.The cooling in northern China in the LIA is about -1 3℃ lower than the present.Agriculture tends to ameliorate the large scale cooling(from -1.3℃ to -0.8℃).Agriculture causes widespread decreases in precipitation in eastern China in the LIA,but not under modern conditions.The different land surface energy balances induced by agriculture in different periods are discussed to explain the different climate effects of agriculture.更多还原