Spatiotemporal analysis of air temperature indices, aridity conditions, and precipitation in Iran

Global warming has become a major threat to life on the earth, and recognizing its impacts can definitely be useful in controlling mitigating adverse effects. In this study, time series variations air temperature indices (frost days, Tmin, Tmax, Tmean, Tminmin, Tmaxmax, Tsoil-min), De Martonne aridity index (IDM), total precipitation were investigated using long-term meteorological data (1960–2019) of 31 synoptic stations throughout Iran. The results indicated that more than 94% had increasing trend which about 70% significant at 0.05 level. average increase Tmin was calculated approximately 1.7 times higher Tmax also Tminmin 2.5 Tmaxmax. Our findings showed abrupt changes mostly observed 1990s upward 87% all stations. Increase annual Tmean rate 0.3 °C per decade reduction 5 mm led decrease IDM by 0.35 intensity tropical regions cold regions. Trend analysis partial before after change point trends negative, but turned positive afterwards some located northwestern mountainous country. revealed climate Iran, general, warmer drier past 60 years continuation current global will exacerbate problem future.