【作者】 刘哲；

【导师】 李国庆；

【作者基本信息】 鲁东大学 ， 地理学， 2023， 硕士

【摘要】 草地具有重要的自然生态意义和社会经济价值。由于土地廉价、风能丰富等原因,全球有大量风电场建立在草地上。然而,现有研究表明,风电场会对草地的地表温度等诸多环境要素产生影响。环境的变化势必影响草地植被的物候,当前尚不明晰风电场对多种类型草地物候的影响。为此,本文在全球范围内选取了风电场分布的4种草地类型作为研究区,首先,利用MODIS数据计算了研究区的植被指数日数据,并使用新型插值法和Whittaker平滑法剔除了该日数据中大量的植被指数异常值,获得高质量植被指数日数据;然后,使用动态阈值法从高质量日数据中提取了4个研究区的草地物候信息,并通过比较风电场建成后较未建前的物候差异及每个研究区内不同区域间的物候差异,分析了风电场对上述4种不同类型草地物候的影响;最后,利用降水数据和地表温度数据结合Pearson相关性分析法和单因素方差分析法探究了风电场影响物候的原因,通过比较风电场建成后与未建前草地植被净初级生产力(NPP)的差异分析了物候变化对草地生产力的影响,使用多种气候数据讨论了物候变化对草地土壤湿度的影响。本文的研究结果显示:(1)风电场可延长草地的物候期。典型草原的生长季因风电场的影响延长约3 d～5 d,旺季均延长约3 d～4 d;荒漠草原的生长季延长约4 d～5 d;草甸草原的生长季延长最明显,约4 d～7 d;灌木草原的物候没有受到风电场得影响,这可能与灌木物候相对稳定有关。(2)风电场影响不同类型草地物候的原因不同。典型草原因风电场延长的生长季与生长季开始前两个月的地表温度显著相关,旺季延长与其结束前两个月的降水和温度均显著关;荒漠草原生长季延长与其开始前两个月的地表温度相关;草甸草原生长季延长与其结束前两个月的降水显著相关。(3)不同类型草地物候变化对其NPP的影响不同。典型草原的物候期延长可增加植被NPP;荒漠草原物候期延长则会使植被NPP降低,其降低可能与荒漠草原地区的水分匮乏有关;草甸草原的物候期延长对其植被NPP无明显影响,此可能与区域水分相对充足相关。(4)上述3种草地类型土壤湿度均因物候期延长而降低了。典型草原、荒漠草原、草甸草原的物候期延长后,其区域植被的蒸腾量均增加,其中典型草原和草甸草原的植被蒸腾呈显著性增加,表示物候期延长消耗了更多的土壤水分,进而使区域土壤湿度降低了。更多还原

【Abstract】 Grassland has irreplaceable natural ecological significance and social economic value.Due to reasons such as cheap land and abundant wind energy,a large number of wind farms around the world are built on grasslands.However,existing research has shown that wind farms can have many impacts on environmental factors.And changes in the environment will inevitably affect the phenology of grassland vegetation.The impact of wind farms on the phenology of other types of grasslands worldwide is currently unclear.Therefore,this article selects 4 types of grassland with wind farm distribution worldwide as study areas to determine the impact of wind farms on the phenology of different types of grasslands.Firstly,MODIS data is used to calculate the daily vegetation index data of the study area,and new interpolation method and Whittaker smoothing method are used to remove a large number of outlier in the daily vegetation index data,so as to obtain high-quality daily vegetation index data.Then,the dynamic threshold method was used to extract grassland phenological information from high-quality daily data for four study areas.Moreover,by calculating the phenological difference between wind farms after construction and before,in turn comparing that difference between different zones of each study area,the impact of wind farms on the phenology of the four different grasslands mentioned above was analyzed.Finally,the reasons for the impact of wind farms on phenology were explored using precipitation and land surface temperature data combined with Pearson correlation analysis and one-way ANOVA methods;The impact of phenological changes on grassland productivity was analyzed by comparing the difference in net primary productivity(NPP)between wind farms after construction and before;The impact of phenological changes on grassland soil moisture was discussed using various climate data.The research results of this article show that:Wind farms can extend the phenological period of grasslands.The growth season of typical grasslands is extended by 3 ～ 5 days under the operation of wind turbines,and the peak season is extended by 3 ～ 4 days;The growth season of desert grasslands is extended by 4 ～ 5 days;The growth season of the meadow grassland is most significantly prolonged,about 4 ～ 7 days;The phenology of shrub grasslands will not be affected by wind farms,which may be related to the relatively stable phenology of shrubs.The reasons why wind farms can affect the phenology are different in each grassland.The extended growth season of typical grasslands due to wind farms is significantly correlated with the surface temperature in the first two months of the growth season,while the extended peak season is significantly correlated with the precipitation and temperature in the two months before its end;The extension of the desert grassland growth season is related to the surface temperature in the first two months before its onset;The extension of the growth season in the meadow grassland is significantly correlated with the precipitation in the two months before its end.The impact of phenological changes on NPP varies among different types grasslands.Prolonging the phenological period of typical grasslands can increase vegetation NPP;Prolonging the phenological period of desert grasslands will lead to a decrease in vegetation NPP,which may be related to water scarcity in desert grassland areas;The extension of the phenological period of the meadow grassland has no significant impact on its vegetation NPP,which may be related to the relatively sufficient regional water.The soil moisture of grasslands affected by phenology decreases due to the extension of phenological period.After the phenological period of typical grasslands,desert grasslands,and meadow grasslands is extended,the transpiration of vegetation increases.Among them,the vegetation transpiration of typical grasslands and meadow grasslands shows a significant increase,indicating that the extension of phenological period consumes more soil moisture,thereby reducing regional soil moisture.更多还原