Assessment of dust activity and dust-plume pathways over Jazmurian Basin, southeast Iran

- Identification and analysis for the first time of the dust activity over Jazmurian basin, Iran.
- Investigation of the dust-plume pathways and affected area.
- Influence of the Jazmurian dust storms on aerosol loading over southeast Iran.
- The dust storms originating from Jazmurian affect mostly the northern coast of the Arabian Sea and surrounding.

Jazmurian (or hamun-e Jaz Murian) is a dried lake located in a topographic-low basin in southeast Iran and a major source for high dust emissions under favorable weather conditions. This work examines for the first time the dust activity over the basin by classifying the dust events (DEs, visibility <10 km) and dust-storm events (DSEs, visibility <1 km) based on observations at five local meteorological stations during the period 1990-2013. Analysis of the temporal evolution, seasonality, frequency and persistence (duration) of the DEs and DSEs, along with examination of the backward and forward air-mass trajectories in the Jazmurian Basin are the main objectives of the present study. The DEs exhibit maximum frequency in June-July and lowest in autumn and winter, while the DSEs peak mostly during March-May also presenting large variability between the stations. The frequency of both the DEs and DSEs increases during ∼2001-2004 due to a prolonged drought over southeastern Iran, while no significant tendency is found during the period 1990-2013. Further, the DEs and DSEs exhibit a clear diurnal pattern with highest frequency between 15:30 and 18:30 LST due to thermal convection and transported dust plumes. The analysis reveals an average frequency of 12.7 dust-storm days per year, while the DSEs last for 5.1 h, on average, during the dust-storm days. The dust storms originating from Jazmurian affect mostly the northern coast of the Arabian Sea (Makran mountains), the Oman Sea, the southeastern Arabian Peninsula and the western Pakistan, while air masses from the arid/desert areas of central-eastern Iran and Arabia seem to further aggravate the dust-aerosol loading over Jazmurian.