Climate change impacts on water resources in the Low Zab River Basin: a spatiotemporal analysis
Climate change affects water resources in semi-arid basins by altering precipitation, land surface temperature (LST), evapotranspiration, and surface-water persistence. This study assessed hydroclimatic variability in the Lower Zab River Basin (LZRB), Iraq, during 2000–2021 using satellite and reanalysis datasets processed in Google Earth Engine. Linear regression, Mann-Kendall tests, Sen's slope, Spearman correlation, and partial correlation were applied to evaluate trends and climate-water relationships. Surface-water extent showed a slight decreasing tendency (Sen slope = −0.0125% yr−1; p = 0.091), while annual mean precipitation also decreased non-significantly (−0.00114 mm h−1 yr−1; p = 0.191) and LST increased non-significantly (+0.0406 °C yr−1; p = 0.341). Northern and eastern areas were wetter, with higher evapotranspiration and lower LST, whereas the southwest was warmer and drier. Water-body area was more strongly associated with precipitation (R² = 0.6398; r ≈ 0.80) than with LST (R² = 0.483; r ≈ −0.70), while rank-based and partial correlations confirmed LST as an important inverse stress factor. Overall, water-body variability reflects the combined effects of precipitation supply and thermal-evaporative stress, supporting cloud-based geospatial monitoring of climate-water interactions in semi-arid basins.