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    春季草原空气动力学粗糙度遥感估算及影响因子分析

    Remote sensing estimation and influencing factor analysis of spring grassland aerodynamic roughness

    • 摘要: 空气动力学粗糙度(z0)反映地表粗糙元对风力侵蚀力的削弱程度,在干旱半干旱地区土壤风蚀模拟中具有关键作用。探究春季草原地区地表粗糙元遥感估算模型及其影响因子,对提高风蚀模型参数化精度和促进风蚀易发区的可持续发展具有重要意义。基于此,研究以内蒙古自治区锡林郭勒草原为研究区,基于实测z0,采用线性回归分析方法,建立了基于MODIS(MCD43A4)数据的春季z0遥感估算模型,并利用地理探测器方法分析2010-2022年研究区春季z0空间分异的影响因子。研究结果表明:1)利用MODIS数据短波红外区(SWIR)的波段6和波段7的比值计算的STI与实测z0相关性最高,各植被指数相关性从高到低依次为:STI>NDTI>DFI>LAI>NDVI。2)STI-z0遥感模型(R2=0.83)表现出最佳拟合效果,且验证精度最高(R2=0.53,RMSE=0.1257)。3)2010-2022年春季z0呈现波动上升趋势,多年平均z0为0.55 cm。4)2010-2022年春季z0空间分异主导因子为表征非光合植被覆盖度的DFI指数,其次为风速和植被类型。本文研究结果可以为改进土壤风蚀模型预测精度提供数据,为土壤风蚀的长期动态监测和防治提供科学依据。

       

      Abstract: Background Aerodynamic roughness (z0) reflects the degree to which surface roughness elements attenuate wind erosion force, playing a critical role in soil wind erosion simulation in arid and semi-arid regions. Investigating remote sensing estimation models for surface roughness elements in grassland areas during spring and their influencing factors is of great significance for improving the parameterization accuracy of wind erosion models and promoting sustainable development in wind erosion-prone areas. Methods Based on this, this study selected the Xilingol Grassland in the Inner Mongolia Autonomous Region as the research area. Using measured z0 data and linear regression analysis, the correlations between different vegetation indices and measured z0 were analyzed. A remote sensing estimation model of spring z0 was established based on MODIS (MCD43A4) data. Furthermore, the geographical detector method was used to analyze the influencing factors of the spatial differentiation of spring z0 in the study area from 2010 to 2022. Results 1) The Simple Tillage Index (STI), calculated using the ratio of Band 6 to Band 7 in the short-wave infrared (SWIR) region of MODIS data, had the highest correlation with measured z0. The correlations of the vegetation indices, in descending order, were as follows: STI>NDTI>DFI>LAI>NDVI. 2) The STI-z0 remote sensing model (R² = 0.83) demonstrated the best fit and the highest validation accuracy (R² = 0.53, RMSE = 0.1257). 3) From 2010 to 2022, spring z0 showed a fluctuating upward trend, with a multi-year average z0 of 0.55 cm. 4) The dominant factor influencing the spatial differentiation of spring z0 in the study area from 2010 to 2022 was the Dead Fuel Index (DFI), which represents non-photosynthetic vegetation cover, followed by wind speed and vegetation type. Conclusion The findings of this study can provide data for improving the prediction accuracy of soil wind erosion models and offer a scientific basis for the long-term dynamic monitoring and prevention of soil wind erosion.

       

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