Artificial oasis expansion in arid regions intensifies regional warming and reshapes climate extremes

Land-use change in arid regions profoundly affects regional climate, water resources, and ecological security. Although the climatic effects of natural vegetation restoration have been increasingly documented across humid and semi-arid regions, how artificial oasis expansion—a major anthropogenic land-use transformation in drylands—modulates regional mean climate and extreme events at high spatial resolution remains poorly quantified. Focusing on the northern slope of the Tianshan Mountains as a representative arid-region oasis–desert system, we employ a high-resolution coupled land–atmosphere regional climate model to assess the forcing effects of land-surface evolution on regional climate and extreme events . Results show that artificial oasis expansion increases the growing-season regional mean air temperature by 0.20 °C, with the number of warm days (TX90p) and the warm spell duration index (WSDI) increasing by 5.69% and 9.16%, respectively; the warming hotspots are spatially collocated with the core oasis expansion zone. Total precipitation increases by 1.27 mm overall, yet the hotspot of intensified heavy precipitation (a 5.07% increase) shifts markedly toward the windward slopes of the northern Tianshan Mountains. In contrast, the natural-vegetation scenario produces slight cooling and substantially attenuated climatic responses. Mechanistically, enhanced net radiation driven by reduced surface albedo constitutes the primary energy source for regional warming, while thermally-induced local circulation anomalies arising from the oasis–desert thermal contrast form a dynamical conduit that enables cross-scale moisture transport. These findings reveal a distinct climate-amplification effect associated with artificial oasis expansion in arid regions and highlight the necessity of incorporating the regulation of regional climate extremes into integrated assessments of ecological engineering projects.