Modulation of atmospheric dynamics and dust emissions in southwest Asia by the Caspian Sea– Hindu Kush Index

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Kaskaoutis D.G., Houssos E.E., Rashki A., Bartzokas A., Legrand M., Francois P. and Kambezidis H D. (2016)
In the proceedings of the 13th International Conference on Meteorology, Climatology and Atmospheric Physics, Thessaloniki, Greece, September 2016

Abstract

This paper introduces a new climatology index, the Caspian Sea – Hindu Kush Index (CasHKI), which consists of changes in the mean sea level pressure (MSLP) gradient between the Caspian Sea (CS, 40-50oN, 50-55oE) and Hindu Kush (HK, 35-40oN, 70-75oE) that modulate the atmospheric dynamics and dust activity over southwest (SW) Asia. CasHKI is defined as the difference in MSLP anomalies between the CS and HK (MSLPanom.CS – MSLPanom.HK) and is initially examined during the summer months (June-September, JJAS) of 2000-2014. NCEP-NCAR data for MSLP, geopotential height at 700 hPa and surface meridional wind, along with meteorological records at Zabol, east Iran, IDDI (Infrared Difference Dust Index) retrievals from Meteosat, MODIS-AOD550, OMI-AI and SPRINTARS model simulations of dust emissions are analyzed as a function of CasHKI. CasHKI variations modulate the atmospheric dynamics over SW Asia, while increase in CasHKI intensity strengthens the northerly flow along eastern Iranian borders (Levar wind), resulting in activation of the dust sources over the region and in significantly larger dust emissions and outflows over the northern Arabian Sea. Further research during the period 1963-2014 verifies the role of CasHKI as a regulatory factor for dust activity over SW Asia even during the winter period.