Search results for "Convective Boundary Layer"
showing 3 items of 3 documents
Northward bursts of the West African monsoon leading to rainfall over the Hoggar Massif, Algeria
2009
The Hoggar Massif is a comparatively populated region in the Sahara, where water supply is a critical problem due to the lack of nearby sources and unaffordable water pumping. In the present paper, we analyse the influence of the West African monsoon (WAM) on precipitation over the Hoggar during summer. We investigate (1) two rainfall events during 23-27 July 2006, accounting for almost half of the precipitation of this year, and (2) the representativity of this period with regard to ERA-40 ECMWF re-analyses (1979 to 2001). By the end of July 2006, two consecutive northward bursts of the WAM flow reached the Hoggar and caused an increase in low-level humidity. In the afternoon of these days…
Dust mobilization and transport in the northern Sahara during SAMUM 2006 – a meteorological overview
2009
The SAMUM field campaign in southern Morocco in May/June 2006 provides valuable data to study the emission, and the horizontal and vertical transports of mineral dust in the Northern Sahara. Radiosonde and lidar observations show differential advection of air masses with different characteristics during stable nighttime conditions and up to 5-km deep vertical mixing in the strongly convective boundary layer during the day. Lagrangian and synoptic analyses of selected dust periods point to a topographic channel from western Tunisia to central Algeria as a dust source region. Significant emission events are related to cold surges from the Mediterranean in association with eastward passing upp…
Radiative and dynamic effects of absorbing aerosol particles over the Pearl River Delta, China
2008
Abstract Results are reported from a ground-based measurement campaign conducted in a highly polluted region in southeast of China in October–November 2004. The experiment focused on absorbing aerosol particles and their effects on the solar radiation field and local meteorology. A Raman lidar in conjunction with Sun photometer data measured profiles of particle extinction; ground-based in situ data of aerosol optical properties were collected by nephelometer and absorption photometer. Exceptionally high values of aerosol optical depth of up to 1.5 were observed. The measurements were input to a radiative transfer model, which simulated high solar radiative forcing values for the aerosol pa…