Climatology of the Sistan Levar wind: Atmospheric dynamics driving its onset, duration and withdrawal

Levar wind is the dominant meteorological and climatic feature in east Iran, blowing from Central Asia to northern coast of Arabian Sea. It also known as “120-days wind” due its mean duration summer season. Although violent responsible for massive dust storms southwest Asia, long-term climatology atmospheric dynamics that facilitate genesis dissipation have not been well documented. This study uses two-phase regression method determining onset, during a 41-years period (1972–2012), based on identification change points data series at Zabol station. The estimated 135 ± 24 days, with remarkable inter-annual variability. onset determined around 22 May ±23 while withdrawal 8 October ±25 days. On average, occur between speeds 4.6–7.7 ms?1 spring 3.9–6.7 autumn, respectively. A comprehensive analysis performed first time examine are associated Levar. early years characterized by stronger winds May, no considerable changes detected late years. Changes sea-level pressure (MSLP) dipole Caspian Sea India/Pakistan forces Therefore, (late) (withdrawal) driven MSLP over these areas, local topography play an important role. seems be modulated CasHKI (Caspian Hindu Kush Index), Caspian-Sea High (majorly) Indian/Pakistan monsoon thermal low (secondarily) affect intensity.