Recent changes in ground surface thermal regimes in the context of air temperature warming over the Heihe River Basin, China

摘要

Changes-in-ground-surface-thermal-regimes-play-a-vital-role-in-surface-and-subsurface-hydrology,-ecosystem-diversity-and-productivity,-and-global-thermal,-water-and-carbon-budgets-as-well-as-climate-change.-Estimating-spring,-summer,-autumn-and-winter-air-temperatures-and-mean-annual-air-temperature-(MAAT)-from-1960-through-2008-over-the-Heihe-River-Basin-reveals-a-statistically-significant-trend-of-0.31-°C/decade,-0.28-°C/decade,-0.37-°C/decade,-0.50-°C/decade,-and-0.37-°C-/decade,-respectively.-The-averaged-time-series-of-mean-annual-ground-surface-temperature-(MAGST)-andmaximum-annual-ground-surface-temperature(MaxAGST)-for-1972-2006-over-the-basin-indicates-a-statistically-significant-trend-of-0.58-°C/decade-and-1.27-°C/decade,-respectively.-The-minimum-annual-ground-surface-temperature-(MinAGST)-in-the-same-period-remains-unchanged-as-a-whole.-Estimating-surface-freezing/thawing-index-as-well-as-the-ratio-of-freezing-index-to-thawing-index-(RFT)in-the-period-between-1959-and-2006-over-the-basin-indicates-a-statistically-significant-trend-of-42.5-°C-day/decade,-85.4-°C-day/decade-and-0.018/decade,-respectively.