Radiative effects of long-range-transported Saharan air layers as determined from airborne lidar measurements

doi:10.5194/acp-2020-420

GSTDTAP > 地球科学

DOI	10.5194/acp-2020-420
	Radiative effects of long-range-transported Saharan air layers as determined from airborne lidar measurements
	Manuel Gutleben, Silke Groß, Martin Wirth, and Bernhard Mayer
	2020-06-08
发表期刊	Atmospheric Chemistry and Physics
出版年	2020
英文摘要	The radiative effect of long-range-transported Saharan air layers is investigated on the basis of simultaneous airborne high spectral resolution and differential absorption lidar measurements in the vicinity of Barbados. Within the observed Saharan air layers increased water vapor concentrations compared to the dry trade wind atmosphere are found. The measured profiles of aerosol optical properties and water vapor mixing ratios are used to characterize the atmospheric composition in radiative transfer calculations, to calculate radiative effects of moist Saharan air layers and to determine radiative heating rate profiles. An analysis based on three case studies reveals that the observed enhanced amounts of water vapor within Saharan air layers have a much stronger impact on heating rate calculations than mineral dust aerosol. Maximum mineral dust short-wave heating and long-wave cooling rates are found in altitudes of highest dust concentration (short-wave: +0.5 Kd⁻¹, long-wave: −0.2 Kd⁻¹, net: +0.3 Kd⁻¹). However, when considering both aerosol concentrations and measured water vapor mixing ratios in radiative transfer calculations the maximum heating/cooling rates shift to the top of the dust layer (short-wave: +2.2 Kd Kd⁻¹, long-wave: −6.0 to −7.0 Kd⁻¹, net: −5.0 to −4.0 Kd⁻¹). Additionally, the net-heating rates decrease with height – indicating a destabilizing effect in the dust layers. Long-wave counter radiation of Saharan air layers is found to reduce cooling at the top of the subjacent marine boundary layers and might lead to less convective mixing in these layers. The overall short-wave radiative effect of mineral dust particles in Saharan air layers indicates a maximum magnitude of −40 Wm⁻² at surface level and a maximum of −25 Wm⁻² at the top of the atmosphere.
领域	地球科学
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文献类型	期刊论文
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/274356
专题	地球科学
推荐引用方式 GB/T 7714	Manuel Gutleben, Silke Groß, Martin Wirth, and Bernhard Mayer. Radiative effects of long-range-transported Saharan air layers as determined from airborne lidar measurements[J]. Atmospheric Chemistry and Physics,2020.
APA	Manuel Gutleben, Silke Groß, Martin Wirth, and Bernhard Mayer.(2020).Radiative effects of long-range-transported Saharan air layers as determined from airborne lidar measurements.Atmospheric Chemistry and Physics.
MLA	Manuel Gutleben, Silke Groß, Martin Wirth, and Bernhard Mayer."Radiative effects of long-range-transported Saharan air layers as determined from airborne lidar measurements".Atmospheric Chemistry and Physics (2020).