基于3S的京津风沙源治理工程区植被覆盖和气候要素变化分析

为分析评估京津风沙源治理工程区植被覆盖和气候要素变化, 收集工程实施前、后各时期工程区域土地利用类型数据、MODIS产品植被覆盖(NDVI)数据和气象站点月值数据, 利用最小二乘法拟合分析工程区NDVI和蒸散时空变化规律; 利用MK非参数检验分析区域气候要素时空变化格局。结果表明(1)近25年来工程区土地利用类型变化不大, 植被面积未有显著增加; (2)近20年, 工程区81.5%的区域生长季平均NDVI呈上升趋势, 其中37.6%的区域呈显著上升趋势(P < 0.05), 平均变率0.005 a-1; 同时, 99.8%的工程区域植被蒸散呈上升趋势, 其中95.3%的区域呈显著上升趋势(P < 0.05), 平均变率109.11 kg·m-2·a-1; (3)工程实施前、后对比, 气候要素变化趋势发生明显变化, 工程实施前工程区平均气温呈上升趋势, 其中78%以上气象站点平均气温距平呈显著上升趋势, 上升幅度为0.01 ℃·a-1; 降雨量和平均相对湿度呈减少趋势, 其中16%的气象站点降水距平百分率呈显著减少趋势, 减少幅度在0.33% a-1以上。工程实施后, 工程区内气温呈降低趋势, 其中24%的气象站点平均气温距平呈显著下降趋势, 降幅在0.008 ℃·a-1以上; 降雨量和平均相对湿度呈增加趋势, 其中22%的站点降水距平百分率呈显著增加趋势, 幅度约为0.22% a-1。总体上, 京津风沙源治理工程实施近20年来风沙天气得到明显改善, 植被恢复及原有植被质量的提升是环境改善的主要原因。

Analysis of vegetation cover and climatic elements change in the Beijing-Tianjin sandstorm source area based on 3S technology

In order to analyze the change of vegetation cover and climatic elements in the Beijing-Tianjin sandstorm source area,we collected land use type data,NDVI parameters,and month data of meteorology stations before and after the implementation of the project in the Beijing-Tianjin sandstorm source area.We analyzed the spatial-temporal change of NDVI and evapotranspiration by least square method in the project area.By using MK nonparametric test,we analyzed spatial-temporal variation of climate elements in the study region.The results showed that:(1)The land use type had little change in the past 25 years.There was no significant change in the vegetation cover.(2)In the past 20 years,the average variability of the growing season average NDVI was 0.005 a^-1.The growing season average NDVI showed an increasing trend in 81.5%of the project area,around 37.6%of which increased significantly(P<0.05).The average variability of the vegetation evapotranspiration was 109.11 kg·m^-2·a^-1,vegetation evapotranspiration showed an increasing trend in 99.8%of the project area,around 95.3%of which increased significantly(P<0.05).(3)Before and after the implementation of the project,the climatic elements in the project area changed significantly.Before the implementation of the project,the average temperature showed an increasing trend.In 78%of the meteorology station,the mean temperature anomaly significantly increased about 0.01℃·a^-1.The precipitation and relative humidity showed a decreasing trend,and in 16%of the meteorology station,the mean precipitation anomaly significantly decreased by 0.33%a^-1.After the implementation of the project,the temperature showed a decreasing trend in the project area.In 24%of the meteorology station,the mean temperature anomaly significantly deceased more than 0.008℃·a^-1.The precipitation and relative humidity showed an increasing trend,and in 22%of the meteorology station,the mean precipitation anomaly significantly increased about 0.22%a^-1.In general,the sandstorm weather in the Beijing-Tianjin sandstorm source area was obviously improved after almost two decades implementation of the project because of vegetation restoration.