Absorption of sunlight by dust as inferred from satellite and ground-based remote sensing

TLDR: In this paper, the authors used satellite spectral measurements and ground-based sky measurements to demonstrate that Saharan dust absorption of solar radiation is several times smaller than the current international standards.

Abstract: Dust absorption of solar radiation is not well known due to limitations in the accuracy of in situ measurements. Here we report two new independent remote sensing techniques that provide sensitive measurements of dust absorption. One uses satellite spectral measurements, the second ground based sky measurements. Both techniques demonstrate that Saharan dust absorption of solar radiation is several times smaller than the current international standards. For example, at wavelength of 0.64 µm the dust single scattering albedo is reported here as 0.97±0.02 rather than 0.87±0.04 in recent review.

Figures

Figure 4. (A) Comparison between the single scattering albedo, o,, derived from Landsat TM images over Senegal in 1987 (full symbols) and w, derived from the AERONET sun/sky radiometers solar almucantar measurements (empty symbols). To compare the two methods, linear fits (color lines) were performed to the AERONET data and extrapolated to the Landsat optical thickness. The uncertainty in the fit is calculated using a “bootstrap technique” and shown by the bars in the figure. (B): The volume size distribution of the dust, measured by AERONET, indicates dominance by large dust particles. CVCapo Verde, SV- Solar Village, 7, dust optical thickness.

Figure 2. Landsat TM images of dust over the coast of Senegal. A) image for May 3, 1987 (less dust, ~&.8) and (B) April 17, 1987 (heavy dust, ~.,=2.4). Color scale: 0.49 urn (blue), 0.55 urn (green) and 0.66 urn (red). C) spectral apparent reflectance for the less dusty (green) and very dusty (red) days for 8 grid points as indicated (raw and column) in the image. The solid-heavy lines are the average values for the entire land area, given with the standard deviations. Note the systematic increase in the image brightness in all the grid boxes from the less dusty to heavy dust

Frequently asked questions

Q1. What contributions have the authors mentioned in the paper "Absorption of sunlight by dust as inferred from satellite and gound-based remote sensing" ?

Here the authors report two new independent remote sensing techniques that provide sensitive measurements of dust absorption. For example, at wavelength of 0. 64 pm the dust single scattering albedo is reported here as 0. 97kO. 02 rather than 0. 8710. 04 in recent review.