Spatio-temporal distribution characteristics and influencing factors of drought in the Liaohe river basin, China

Effective identification of drought-related events and quantitative analysis the spatio-temporal evolution drought are essential for regional disaster prevention mitigation sustainable development. Based on monthly precipitation average temperature data from 113 grid points in Liaohe River Basin (LRB) 1961 to 2018, this study evaluated standardized evapotranspiration index (SPEI) monthly, quarterly, 6-monthly, annual scales. Run-length theory was used extract three characteristic variables drought—frequency, severity, duration—for different grades drought. Linear regressions, Manner–Kendall mutation tests, correlations, other methods were analyze distribution characteristics levels their influencing factors. Results research can provide a scientific reference mitigation, water conservancy project planning construction, land space ecological restoration, development protection LRB. Our results indicated following: 1) overall, short-term SPEI (monthly, quarterly) showed an upward trend (0.06/103a, 0.01/103a), while long-term (6-monthly, annual) downward (−0.01/103a, −0.3/103a), overall change occurred stages, specifically stable–decline–increase. From seasonal point view, spring, summer, autumn trend, although multiple mutations during all seasons, they not significant ( p > 0.05). 2) Moderate most frequently (32 times) concentrated northern western parts The severity extreme upper reaches Chagan Mulun low, with minimum −7.07, durations mild, moderate, severe, 2, 2-2.5, 2–3, 3–4 months, respectively. 3) SPEI-1 (monthly) strongest correlation air temperature, which decreased increasing time frames, such that SPEI-12 (annual) weakest correlation. correlations between at scales highly < 0.01), strength much greater than indicating had impact conditions