BoDEx

The Bodélé Dust Experiment

The Bodélé Depression in Chad is the single dustiest place in the world. The depression, now hyper-arid, was 5000 years ago part of Lake Mega-Chad, an inland body of water the size of the Caspian Sea.

BoDEx sought to explain (i) the processes of dust emission and transport from the Bodélé and (ii) the characteristics of dust aerosols which determine the radiative forcing. The field campaign in the Bodélé in Spring 2005 was the first to this remote region. It provided detailed measurements of the Bodélé low-level jet, a wind maximum only 500m above the surface which leads to pronounced dust emission as it is channeled and accelerated through the gap between the Tibesti and Ennedi mountain ranges. The field campaign also sampled the dust and found that it consists mainly of diatomite sediment, from diatoms that lived in Lake Mega-Chad.

BoDEx was funded by the Royal Geographical Society Gilchrist Educational Trust. It was a collaboration between the University of Oxford, University College London, Birkbeck College London, Salford University and Direction des Resources en Eau et de la Météorologie (N’Djamena).

Pibal wind profile BoDEx

Time-height profile of wind speed from pilot balloon data during BoDEx: the Bodélé low level jet is plainly visible (orange and red contours). Source: Washington et al (2006).

 

Contacts

Prof Richard Washington
Dr Sebastian Engelstaedter

BoDEx publications

Washington, R., and M. C. Todd (2005), Atmospheric controls on mineral dust emission from the Bodélé Depression, Chad: The role of the low level jet, Geophys. Res. Lett., 32(17), L17701, doi: 10.1029/2005gl023597

Eckardt, F.D., Coetzee, S.H., and Washington, R. (2005) SEM view of world’s most significant dust cloud sampled at Chicha, The Chad, Bodele Depression, Sahara. Microscopy Society of Southern Africa Proceedings, 35: 23.

Giles, J. (2005), Climate science: The dustiest place on Earth, Nature 434: 816-819 (14 Apr 2005).

Drake, N. and C. Bristow (2006) Shorelines in the Sahara: geomorphological evidence for an enhanced monsoon from palaeolake Megachad. The Holocene 16(6): 901-911.

Engelstaedter, S., I. Tegen, and R. Washington (2006), North African dust emissions and transport, Earth-Science Reviews, 79(1–2), 73-100, doi: 10.1016/j.earscirev.2006.06.004.

Giles, J. (2006), Research Highlights: Amazon given a good dust, Nature 444: 126 (9 Nov 2006).

Koren, I., Y.J. Kaufman, R. Washington, M.C. Todd, Y. Rudich, J.V. Martins and D. Rosenfeld (2006) The Bodélé depression: a single spot in the Sahara that provides most of the mineral dust to the Amazon forest. Environ. Res. Lett., 1: 1-5

Tegen, I., B. Heinold, M. Todd, J. Helmert, R. Washington, and O. Dubovik (2006) Modelling soil dust aerosol in the Bodélé depression during the BoDEx campaign. Atmos. Chem. Phys., 6: 4345–4359

Washington, R., M. C. Todd, S. Engelstaedter, S. Mbainayel, and F. Mitchell (2006), Dust and the low-level circulation over the Bodélé Depression, Chad: Observations from BoDEx 2005, J. Geophys. Res., 111(D3), D03201, doi: 10.1029/2005jd006502.

Washington, R., M. C. Todd, G. Lizcano, I. Tegen, C. Flamant, I. Koren, P. Ginoux, S. Engelstaedter, C. S. Bristow, C. S. Zender, A. S. Goudie, A. Warren, and J. M. Prospero (2006), Links between topography, wind, deflation, lakes and dust: The case of the Bodélé Depression, Chad, Geophys. Res. Lett., 33(9), L09401, doi: 10.1029/2006gl025827.

Engelstaedter, S., and R. Washington (2007), Temporal controls on global dust emissions: The role of surface gustiness, Geophys. Res. Lett., 34(15), L15805, doi: 10.1029/2007gl029971.

Engelstaedter, S., and R. Washington (2007), Atmospheric controls on the annual cycle of North African dust, J. Geophys. Res., 112(D3), D03103, doi: 10.1029/2006jd007195.

Todd, M. C., R. Washington, J. V. Martins, O. Dubovik, G. Lizcano, S. M’Bainayel, and S. Engelstaedter (2007), Mineral dust emission from the Bodélé Depression, northern Chad, during BoDEx 2005, J. Geophys. Res., 112, D06207, doi:10.1029/2006JD007170.

Todd, M. C., D. Bou Karam, C. Cavazos, C. Bouet, B. Heinold, J. M. Baldasano, G. Cautenet, I. Koren, C. Perez, F. Solmon, I. Tegen, P. Tulet, R. Washington, and A. Zakey (2008), Quantifying uncertainty in estimates of mineral dust flux: An intercomparison of model performance over the Bodélé Depression, northern Chad, Journal of Geophysical Research: Atmospheres, 113(D24), D24107, doi: 10.1029/2008jd010476.

Todd, M. C., R. Washington, S. Raghavan, G. Lizcano, and P. Knippertz (2008), Regional model simulations of the Bodélé low-level jet of Northern Chad during the Bodélé dust experiment (BoDEx 2005), Journal of Climate, 21(5), 995-1012, doi: 10.1175/2007JCLI1766.1.

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