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How well do analyses capture dust-generating winds in the Sahara and Sahel?

Roberts, A.; Marsham, J. H.; Knippertz, P. ORCID iD icon; Parker, D. J.

Abstract (englisch):

Airborne mineral dust is important for weather, climate and earth-system prediction. Uncertainty in winds, as well as the land-surface, are known to be key to model uncertainties for dust uplift. Recent research has shown that during the summer wet season in the Sahel strong winds generated by the cold outflow from organized convective systems are an important dust storm mechanism (so called haboobs), while over the inner Sahara nocturnal low-level jets forming on the pressure gradient around the heat low dominate. Together the Sahel and Sahara are the world's largest dust source. Until now there has been a severe shortage of data for evaluating models for this region. Here, we bring together new observations from the remote Sahara, made during the Fennec project, with Sahelian data from the African Monsoon Multidisciplinary Analysis (AMMA), to provide an unprecedented evaluation of dust-generating winds in the European Centre for Medium-Range Weather Forecasts ERA-Interim (ERA-I) reanalysis. Differences between observations and ERA-I are explored with specific attention to monsoon and non-monsoon influenced regions. The main results are: (1) High speed winds in instantaneous ERA-I grid-box mean winds are lacking compared to time-averaged wind speed observations; (2) agreement between ERA-I and observations is lower during the monsoon season, even in parts of the Sahara not directly affected by the monsoon; and (3) both the seasonal and diurnal variability is under-represented in ERA-I. ... mehr

Zugehörige Institution(en) am KIT Institut für Meteorologie und Klimaforschung – Forschungsbereich Troposphäre (IMK-TRO)
KIT-Zentrum Klima und Umwelt (ZKU)
Publikationstyp Vortrag
Publikationsjahr 2016
Sprache Englisch
Identifikator KITopen-ID: 1000064988
HGF-Programm 12.01.02 (POF III, LK 01) Proc.res.f.multisc.predictab.of weather
Veranstaltung EGU General Assembly, 17–22 April 2016, Vienna, A
Bemerkung zur Veröffentlichung EGU2016-8072
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