【作者】 刘宁微；

【导师】 周军； 周小珊；

【作者基本信息】 南京气象学院 ， 气象学， 2003， 硕士

【摘要】 辽西地区近几十年来土地退化严重，已成为生态脆弱区。本文利用中尺度模式(MM5V3-5)，选择2001年6、7、8月份的资料，根据辽西地区土地退化的有关调查材料，对模式中的下垫面状况(landuse)进行改变，模拟植被退化和恢复后，辽西地区的温度、热通量变化。选定120°E、43°N为模式运行区域中心，采用2层套网格方案，粗网格分辨率为51km，细网格分辨率为17km。预报区域格点数粗网格为65×71，细网格为73×82。 模拟结果表明：在辽西部分地区植被退化后，当地6、7、8三个月的夏季平均气温和平均地面温度升高，两者的日较差增大，平均感热通量及其日较差也增大，平均潜热通量及其日较差减小；平均气温升高0～0.5℃，平均地面温度升高0～1.0℃，平均感热通量增大5～40 w/m~2，约8～55％，平均潜热通量减小5～60 w/m~2，约4～48％。植被退化所引起的午后温度和热通量的变化大于平均温度和热通量的变化，14：00前后气温升高0～0.8℃，地面温度升高0.3～2.1℃，感热通量增大20～100 w/m~2，潜热通量减小20～140 w/m~2；夜间温度和热通量的变化小于平均变化，清晨05：00前后气温将升高0.05～0.3℃，地面温度将升高0.1～0.4℃，感热通量增大1～6 w/m~2，潜热通量减小2～6 w/m~2。 在部分地区植被恢复后，当地的夏季平均气温和平均地面温度降低，两者的日较差减小，平均感热通量及其日较差也减小，平均潜热通量及其日较差增大；平均气温降低0.05～0.35℃，平均地表温度降低0.1～0.8℃，平均地面感热通量减小5～25 w/m~2，约8～40％，平均潜热通量增大5～40 w/m~2，约4～35％。植被恢复所引起午后温度和热通量的变化总体来看也大于平均温度和热通量的变化，午后14：00前后气温降低0.1～0.5℃，地面温度降低0.2～1.6℃，感热通量减小10～50w/m~2，潜热通量增大20～100w/m~2；清晨05：00前后气温降低0.1～0.4℃，地面温度降低0.1～0.3℃，感热通量减小2～12w/m~2，潜热通量增大3～15w/m~2。值得注意的是，在下垫面状况改变的周边地区，平均温度和热通量也有一定程度的变化。 由于下垫面植被状况的变化，高空气压场和温度场也随之发生一些变化。无论植被是退化还是恢复，都会使其上部的气压降低，影响的层次可达200hPa附近，这种变化似乎在下垫面改变地区的东部下游更明显一些，垂直方向气压降低的中心在850hPa左右。植被的退化会使其上部的温度升高，与其相邻的地区温度降低；植被的恢复会使其上部的温度降低，与其相邻的地区温度升高。 本研究结果表明：辽西地区植被变化对当地气候的影响是比较明显的，在辽西地区植被变化的几种形式中，森林的消失和恢复是影响当地气候变化最重要的形式。因此，保护森林或者实施积极的退耕还林、退草还林是改善气候环境最重要的工作。这一结果可为当地政府规划生态环境的改善工作提供重要参考。更多还原

【Abstract】 The situation has been serious that the land has degraded in the west of Liaoning province during recent decades. A lot of areas have already become the fragile district of the ecology. The mesoscale(MM5V3-5) model was used to simulate the change of temperature, heat flux by means of changing landuse according to the survey data about the land degradation and renewing in the west of Liaoning, which used data in June,July and August,2001. Choose 120 E,43 ?N as the operation center of the model and use two layers of nested schemes.The resolution ration of the coarse nest is 51km while that of the fine nest is 17km. The number of the grid in the focast area of the coarse nest is 65 ×71 while that of the fine nest is 73 × 82.The results show that the local average temperature and average surface temperature will rise,and both daily difference will rise,too.Average sensible heat flux and its daily difference will also increase while average latent heat flux and its daily difference will reduce after the vegetation degration of some area in the west of Liaoning province; the average temperature will raise 0-0.5℃, average surface temperature will raise 0-1.0℃, average sensible heat flux will increase 5-40w/m2, about 8-55% and average latent heat flux will reduce 5-60w/m2, about 4-48%. The change caused by the vegetation degration of the tempreture and the heat flux in the afternoon is more than that of the average. At about 14:00, the tempreture will raise 0-0.8℃,surface temperature will raise 0.3-2.1℃, sensible heat flux will increase 20-100w/m2 and latent heat flux will reduce 20-140w/m2; the change caused by the vegetation degration of the tempreture and the heat flux in the early moning is less than that of the average. At about 05: 00, the tempreture will raise 0.05-0.3℃,surface temperature will raise 0.1-0.4℃, sensible heat flux will increase 1-6w/m2 and latent heat flux will reduce 2-6w/m2.The local average temperature and average surface temperature will drop, and both daily difference will drop,too.Average sensible heat flux and its daily difference will also reduce while average latent heat flux and its daily difference will increase after the vegetation is renewed partically in the west of Liaoning province; the average temperature will drop 0.05-0.35 ℃, average surface temperature will drop 0.1-0.8℃, average sensible heat flux will reduce 5-25w/m2, about 8-40% and average latent heat flux will increase 5-40w/m2, about 4-35%. The change caused by the vegetation renewed of the tempreture and the heat flux in the afternoon is more than that of the average. At about 14:00, the tempreture will drop 0.1-0.5℃,surface temperature will drop 0.2-1.6℃, sensible heat flux will reduce 10~50w/m and latent heat flux will increase 20-100w/m2; At about 05: 00, the tempreture will drop 0.1-0.4℃,surface temperature will drop 0.1-0.3 C, sensible heat flux will reduce 2-12w/m2 and latent heat flux will increase 3-15w/m2. What shoud bepaid attention to is that there are also some changes of the average tempreture and heat flux in the area where the landuse hasn’t been alterd.The baric field and the tempreture field of high latitude will have some changes because of the change in the vegetation states of the landuse. Whether the vegetation degraded or renewed, it can both make the atmospheric pressure over it drop, and the height can reach about 200hPa. This change seems to be more obvious to the east of the area where the landuse has been changed, in the vertical direction the center of the pressure dropping lies at about 850hPa. The degraded vegetation can make the tempreture of it’s upside rise and the tempreture beside it drop; the renewed vegetation can make the tempreture of it’s upside drop and the tempreture beside it rise.The results of the study show that the affections to the local climate are rather obvious when the vegetation are changed in the west of Liaoning province. Of the several kinds of vegetation change in the west of Liaoning province, the vanish and the resume of the forest更多还原