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Modelling Leaf Area Index and Land Surface Temperature to Assess Their Changing Trends and Relationships From Global to Regional Scales
Azad Rasul
Sa'ad Ibrahim
Ajoke Onojeghuo
Heiko Balzter
出版
SSRN
, 2020
URL
http://books.google.com.hk/books?id=7QbczwEACAAJ&hl=&source=gbs_api
註釋
Although the way in which vegetation phenology mediates the feedback of vegetation to climate system is now well understood, the magnitude of these changes is still unknown. We lack a thorough sufficient understanding of how the recent shift in phenology may impact on, for example, land surface temperature. To address this issue, it is important to quantify these impacts and identify patterns from global to regional scale. This study examines the trend and linear regression modelling of high-quality leaf area index (LAI) and land surface temperature (LST) derived from the Moderate Resolution Imaging Spectro-radiometer (MODIS) data, specifically to assess their spatial distribution and changing trends at continental and regional scales. The change detection approach employed to quantify the inter-annual variability in the global LAI and LST between two periods (2003-2010 and 2011-2018) demonstrates more positive LAI trends than negative, while for LST most changes were not significant. The relationships between LAI and LST were assessed across the continent to ascertain the response of vegetation to change in LST in Australia (R2= 0.487, negative), Africa (R2= 0.001), North America (R2= 0.641), Central America (R2= 0.119, negative), South America (R2= 0.253) and Europe (R2= 0.740). Medium temperature enhances photosynthesis and lengthens the growing season in Europe. We also found a significant greening trend in China (R2 =0.82***) and India (R2 =0.74***). The relationships between LAI and LST in these most prominent greening countries of the world are R2 = 0.057 and R2 = 0.234 for China and India, respectively. Our deductions here are twofold, (1) In China, an insignificant association appeared between greening trend and temperature. (2) In India, the significant greening trend is assisting to lower the temperature and if the greening trend continues, temperatures will stabilize. We attribute these changes to land use management and climate mitigation policies adopted by these countries.
