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A Climatology of Dust Emission Events from Northern Africa Using Long-term Surface Observations : Volume 14, Issue 6 (18/03/2014)

By Cowie, S. M.

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Book Id: WPLBN0003974688
Format Type: PDF Article :
File Size: Pages 44
Reproduction Date: 2015

Title: A Climatology of Dust Emission Events from Northern Africa Using Long-term Surface Observations : Volume 14, Issue 6 (18/03/2014)  
Author: Cowie, S. M.
Volume: Vol. 14, Issue 6
Language: English
Subject: Science, Atmospheric, Chemistry
Collections: Periodicals: Journal and Magazine Collection (Contemporary), Copernicus GmbH
Historic
Publication Date:
2014
Publisher: Copernicus Gmbh, Göttingen, Germany
Member Page: Copernicus Publications

Citation

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Marsham, J. H., Knippertz, P., & Cowie, S. M. (2014). A Climatology of Dust Emission Events from Northern Africa Using Long-term Surface Observations : Volume 14, Issue 6 (18/03/2014). Retrieved from http://www.ebooklibrary.org/


Description
Description: Institute for Climate and Atmospheric Science, School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK. Long-term (1984–2012) surface observations from 70 stations in the Sahara and Sahel are used to explore the diurnal, seasonal and geographical variations in dust emission events and thresholds. The frequency of dust emission (FDE) is calculated using the present weather codes of SYNOP reports. Thresholds are estimated as the wind speed for which there is a 50% probability of dust emission and are then used to calculate strong wind frequency (SWF) and dust uplift potential (DUP), where the latter is an estimate of the dust-generating power of winds. Stations are grouped into six coherent geographical areas for more in-depth analysis.
FDE is highest at stations in Sudan and overall peaks in spring north of 23° N. South of this, where stations are directly influenced by the summer monsoon, the annual cycle in FDE is more variable. Thresholds are highest in northern Algeria, lowest in the latitude band 16–21° N and have greatest seasonal variations in the Sahel. Spatial variability in thresholds partly explain spatial variability in frequency of dust emission events on an annual basis. However, seasonal variations in thresholds for the six grouped areas are not the main control on seasonal variations in FDE. This is demonstrated by highly correlated seasonal cycles of FDE and SWF which are not significantly changed by using a fixed, or seasonally varying, threshold. The likely meteorological mechanisms generating these patterns such as low-level jets and haboobs are discussed.


Summary
A climatology of dust emission events from northern Africa using long-term surface observations

Excerpt
Ackerman, S. and Cox, S.: Surface weather observations of atmospheric dust over the southwest summer monsoon region, Meteorol. Atmos. Phys., 41, 19–34, doi:10.1007/BF01032587, 1989.; Bagnold, R.: The physics of blown sand and desert dunes, Dover Publications, Mineola, NY, USA, 2005.; Allen, C. J. T., Washington, R., and Engelstaedter, S.: Dust emission and transport mechanisms in the central Sahara: fennec ground-based observations from Bordj Badji Mokhtar, June 2011, J. Geophys. Res.-Atmos., 118, 6212–6232, doi:10.1002/jgrd.50534, 2013.; Bou Karam, D., Flamant, C., Knippertz, P., Reitebuch, O., Pelon, J., Chong, M., and Dabas, A.: Dust emissions over the Sahel associated with the West African monsoon intertropical discontinuity region: a representative case-study, Q. J. Roy. Meteor. Soc., 134, 621–634, 2008.; Bristow, C. S., Hudson-Edwards, K. A., and Chappell, A.: Fertilizing the Amazon and equatorial Atlantic with West African dust, Geophys. Res. Lett., 37, L14807, doi:10.1029/2010GL043486, 2010.; Cowie, S. M., Knippertz, P., and Marsham, J. H.: Are vegetation-related roughness changes the cause of the recent decrease in dust emission from the Sahel?, Geophys. Res. Lett., 40, 1868–1872, doi:10.1002/grl.50273, 2013.; Emmel, C., Knippertz, P., and Schulz, O.: Climatology of convective density currents in the southern foothills of the Atlas Mountains, J. Geophys. Res.-Atmos., 115, D11115, doi:10.1029/2009JD012863, 2010.; Engelstaedter, S. and Washington, R.: Atmospheric controls on the annual cycle of North African dust, J. Geophys. Res.-Atmos., 112, D03103, doi:10.1029/2006JD007195, 2007.; Evan, A. T., Heidinger, A. K., and Knippertz, P.: Analysis of winter dust activity off the coast of West Africa using a new 24-year over-water advanced very high resolution radiometer satellite dust climatology, J. Geophys. Res.-Atmos., 111, D12210, doi:10.1029/2005JD006336, 2006.; Fensholt, R., Langanke, T., Rasmussen, K., Reenberg, A., Prince, S. D., Tucker, C., Scholes, R. J., Le, Q. B., Bondeau, A., Eastman, R., Epstein, H., Gaughan, A. E., Hellden, U., Mbow, C., Olsson, L., Paruelo, J., Schweitzer, C., Seaquist, J., and Wessels, K.: Greenness in semi-arid areas across the globe 1981–2007 – an Earth Observing Satellite based analysis of trends and drivers, Remote Sens. Environ., 121, 144–158, doi:10.1016/j.rse.2012.01.017, 2012.; Fiedler, S., Schepanski, K., Heinold, B., Knippertz, P., and Tegen, I.: Climatology of nocturnal low-level jets over North Africa and implications for modeling mineral dust emission, J. Geophys. Res.-Atmos., 118, 6100–6121, doi:10.1002/jgrd.50394, 2013a.; Fiedler, S., Schepanski, K., Knippertz, P., Heinold, B., and Tegen, I.: How important are cyclones for emitting mineral dust aerosol in North Africa?, Atmos. Chem. Phys. Discuss., 13, 32483–32528, doi:10.5194/acpd-13-32483-2013, 2013b.; Forster, P., Ramaswamy, V., Artaxo, P., Berntsen, T., Betts, R., Fahey, D., Haywood, J., Lean, J., Lowe, D., Myhre, G., Nganga, J., Prinn, R., Raga, G., Schulz, M., and Dorland, R. V.: Changes in atmospheric constituents and in radiative forcing, in: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, 2007.; Gillette, D., Adams, J., Endo, A., Smith, P. H., D., and Kihl, R.: Threshold velocities for

 

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