Thermal Impact of Saharan Dust over Land. Part I: Simnulation

Cautenet, G.; Legrand, Michel; Cautenet, S.; Bonnel, B.; Brogniez, Gérard

doi:10.1175/1520-0450(1992)031<0166:tiosdo>2.0.co;2

Cited by 27 publications

(15 citation statements)

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“…However, the magnitude of cooling at the TOA is smaller than that at the surface, because cooling due to the scattering of solar flux is greatly offset by warming due to the absorption of solar and thermal radiation [ Miller and Tegen , ; Shi et al, ; Bi et al, ]. For the diurnal cycle of dust DRE, the surface RF is negative during the daytime because of the loss of sunlight by absorption and backscattering of dust aerosols but is positive during the nighttime as a result of the continuous thermal emission from dust aerosols [ Cautenet et al, ; Claquin et al, ].…”

Section: Direct Radiative Effectmentioning

confidence: 99%

Climate effects of dust aerosols over East Asian arid and semiarid regions

et al. 2014

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East Asia is a major dust source in the world. Mineral dusts in the atmosphere and their interactions with clouds and precipitation have great impacts on regional climate in Asia, where there are large arid and semiarid regions. In this review paper, we summarize the typical transport paths of East Asian dust, which affect regional and global climates, and discuss numerous effects of dust aerosols on clouds and precipitation primarily over East Asian arid and semiarid regions. We hope to provide a benchmark of our present understanding of these issues. Compared with the aerosols of Saharan dust, those of East Asian dust are more absorptive of solar radiation, and its direct radiative forcing at the top of atmosphere is nearly positive or nil. It means that aerosols of East Asian dust can influence the cloud properties not only by acting as cloud condensation nuclei and ice nuclei (via first indirect effect, second indirect effect, and invigoration effect) but also through changing the relative humidity and stability of the atmosphere (via semidirect effect). Converting visible light to thermal energy, dust aerosols can burn clouds to produce a warming effect on climate, which is opposite to the first and second indirect effects of aerosols. The net dust aerosol radiative effects are still highly unclear. In addition, dust can inhibit or enhance precipitation under certain conditions, thus impacting the hydrological cycle. Over Asian arid and semiarid regions, the positive feedback loop in the aerosol-cloud-precipitation interaction may aggravate drought in its inner land.

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Section: Direct Radiative Effectmentioning

confidence: 99%

Climate effects of dust aerosols over East Asian arid and semiarid regions

et al. 2014

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“…Aerosols directly influence the Earth's radiative budget by absorbing, scattering, and emitting LW radiation (Cautenet et al, 1991;Markowicz et al, 2003;Ackerman and Chung, 1992;Haywood et al, 2005) and scattering and absorbing SW radiation (direct effect) Haywood and Boucher, 2000;Harrison et al, 2001;Haywood et al, 2001;Sokolik et al, 2001), and indirectly by altering cloud droplet size distribution (indirect effect) (Twomey, 1977;Albrecht, 1989). Because there is little cloudiness over deserts, the direct radiative effect (DRE) of dust is of primary interest in this study.…”

Section: The Direct Radiative Effect Of Dustmentioning

confidence: 99%

The impact of dust storms on the Arabian Peninsula and the Red Sea

et al. 2015

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Abstract. Located in the dust belt, the Arabian Peninsula is a major source of atmospheric dust. Frequent dust outbreaks and some 15 to 20 dust storms per year have profound effects on all aspects of human activity and natural processes in this region. To quantify the effect of severe dust events on radiation fluxes and regional climate characteristics, we simulated the storm that occurred from 18 to 20 March 2012 using a regional weather research forecast model fully coupled with the chemistry/aerosol module (WRF-Chem). This storm swept over a remarkably large area affecting the entire Middle East, northeastern Africa, Afghanistan, and Pakistan. It was caused by a southward propagating cold front, and the associated winds activated the dust production in river valleys of the lower Tigris and Euphrates in Iraq; the coastal areas in Kuwait, Iran, and the United Arab Emirates; the Rub al Khali, An Nafud, and Ad Dahna deserts; and along the Red Sea coast on the west side of the Arabian Peninsula. Our simulation results compare well with available ground-based and satellite observations. We estimate the total amount of dust generated by the storm to have reached 94 Mt. Approximately 78 % of this dust was deposited within the calculation domain. The Arabian Sea and Persian Gulf received 5.3 Mt and the Red Sea 1.2 Mt of dust. Dust particles bring nutrients to marine ecosystems, which is especially important for the oligotrophic Northern Red Sea. However, their contribution to the nutrient balance in the Red Sea remains largely unknown. By scaling the effect of one storm to the number of dust storms observed annually over the Red Sea, we estimate the annual dust deposition to the Red Sea, associated with major dust storms, to be 6 Mt.

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“…The primary effect of dust on the TIR channel arises from reduced surface insolation. When aerosol loading is high, as is often the case over North Africa, surface temperatures are reduced, leading to less emission in the long wavelengths (Cautenet et al 1992). Indeed, this reduction has been used by Legrand et al (2001) to monitor aerosols in the region.…”

Section: Observing Land-atmosphere Coupling Using Satellite Data (A) mentioning

confidence: 99%

Observations of synoptic-scale land surface variability and its coupling with the atmosphere

Taylor

Parker

Lloyd

et al. 2005

Q. J. R. Meteorol. Soc.

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SUMMARYCloud-free brightness temperatures from satellite are used to interpret changes in the state of the land surface energy balance from day to day across the tropical semi-arid region of North Africa. The method provides an assessment of the spatial and temporal patterns in the surface characteristics. The variability in brightness temperature is closely linked to precipitation, as inferred from available rain-gauge data and satellite cold-cloud imagery. Temperatures drop sharply after rainfall, and increase gradually in subsequent days consistent with surface drying. The analysis shows that surface temperatures (and therefore fluxes) are well-organized at the synoptic scale, and can be linked to the westward propagation of mesoscale convective systems and African easterly waves (AEWs).The modulation of rainfall and cloud cover by weather systems is a key element in producing variability in surface fluxes of heat and moisture. To examine the relationships between surface variability and the atmosphere, a composite of anomalously warm (and dry) surface conditions with spatial coherence over a given longitude band is constructed from satellite data covering a single wet season. Operational analyses are used to examine atmospheric anomalies associated with these composited 'hotspots'. Surface moisture variations on the scale of several hundred km and larger can generate anomalous heat-lows during the day and, according to the operational analyses, generate cyclonic vorticity overnight. These vortices appear to be responsible for the observed modulation of cold cloud in the vicinity of the hotspot, and may influence the characteristics of AEWs in the Northern Sahel. Furthermore, theoretical ideas suggest that surface hotspots are likely to trigger a westward-propagating Rossbywave response; this process is demonstrated here in a simple numerical model.

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Thermal Impact of Saharan Dust over Land. Part I: Simnulation

Cited by 27 publications

References 0 publications

Climate effects of dust aerosols over East Asian arid and semiarid regions

Climate effects of dust aerosols over East Asian arid and semiarid regions

The impact of dust storms on the Arabian Peninsula and the Red Sea

Observations of synoptic-scale land surface variability and its coupling with the atmosphere

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