On Climate Variability in North-East of Iran

Climate variability empowers critical consequences on sustainability of soil and water resources. In this paper the trend of annual and seasonal time scale of temperature (minimum, maximum, average), relative humidity (minimum, maximum, average), precipitation, wind speed, extreme events, cloudiness, reference evapotranspiration employing Mann-kendall and least square errors were studied. These parameters showed direct or indirect effect on climate variability in northeast of Iran. The results, for example in Mashhad station, showed an increasing trend in temperature, decreasing trend in humidity and no trend in precipitation. In addition, there were an increasing trend in the number of clear days (no cloud) and a decreasing trend in number of cloudy days across all study stations but Mashhad.