A low-level jet in eastern Iran: a possible factor in dust events in the region

Document Type: Research Paper


Earth, Ocean and Atmospheric Science Department, Florida State University, Tallahassee, FL 32306, USA


One of the world's major mineral dust source regions lies along the border between Iran and Afghanistan. In this study
it is hypothesized that a low-level jet may play in role in generating the intensity of this source region. The presence of a
low-level jet east of the Seistan mountains is documented here for the first time. The jet exists mainly from May to
September and has a core at 850 mb. Maximum speeds are at 18 UTC and 0 UTC and occur in July-August. In the mean
the core speed attains 20 ms-1 in those months. The jet attains a maximum at night, a minimum during the day. However, the vertical motions associated with it do not fluctuate greatly over the course of the day. The development of the jet during a dust outbreak in 2002 is also described. It arises a day or so before the outbreak and disappears as the outbreak ends.


Main Subjects

Dee, D.P., Coauthors, 2011. The ERA-Interim reanalysis:
configuration and performance of the data assimilation
system. Quarterly Journal of the Royal Meteorological
Society, 137; 553-597.
Lettau, H. H., 1978. Explaining the world’s driest climate.
In: Lettau HH, Lettau K, editors. Exploring the World’s
Driest Climate: Madison, Institute for Environmental
Studies, University of Wisconsin, Madison, WI; p. 182–
Levy, R., C. Hsu, Coauthors, 2015. MODIS Atmosphere
L2 Aerosol Product. NASA MODIS Adaptive
Processing System, Goddard Space Flight Center, USA:
Liu, M., D.L. Westphal, T.R. Holt, Q. Xu, 2000. Numerical
simulation of a low-level jet over complex terrain in
southern Iran. Monthly Weather Review, 128; 1309–
Middleton, N.J., 1986. A geography of dust storms in
south-west Asia. Journal of Climatology, 6; 183–196.
Nicholson, S. E., 2010. A low-level jet along the Benguela
coast, an integral part of the Benguela Current
Ecosystem. Climatic Change, 99; 613-624.
Nicholson, S.E., 2015. The Turkana Low-Level Jet: mean
climatology and association with regional aridity.
International Journal of Climatology, in press.
Parish, T., 2000. Forcing of the summer low-level jet along
the California coast. Journal of Applied Meteorology,
39; 2421–2433.
Prospero, P. Ginoux, O. Torres, S.E. Nicholson, 2002.
Global Soil Dust Sources I: Environmental
Characterization. Reviews of Geophysics, 40(2); 31
Washington, R., M.C. Todd, 2005. Atmospheric controls
on mineral dust emission from the Bodélé Depression,
Chad: The role of the low-level jet. Geophysical
Research Letters, 32; L17701,