Potential of remote sensing of cirrus optical thickness by airborne spectral radiance measurements at different sideward viewing angles
Spectral radiance measurements collected in nadir and sideward viewing directions by two airborne passive solar remote sensing instruments, the Spectral Modular Airborne Radiation measurement sysTem (SMART) and the Differential Optical Absorption Spectrometer (mini-DOAS), are used to compare the rem...
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ftdoajarticles:oai:doaj.org/article:78d9256fe9d74d5c973c32eb64dc259e 2023-05-15T17:36:10+02:00 Potential of remote sensing of cirrus optical thickness by airborne spectral radiance measurements at different sideward viewing angles K. Wolf A. Ehrlich T. Hüneke K. Pfeilsticker F. Werner M. Wirth M. Wendisch 2017-03-01T00:00:00Z https://doi.org/10.5194/acp-17-4283-2017 https://doaj.org/article/78d9256fe9d74d5c973c32eb64dc259e EN eng Copernicus Publications http://www.atmos-chem-phys.net/17/4283/2017/acp-17-4283-2017.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 1680-7316 1680-7324 doi:10.5194/acp-17-4283-2017 https://doaj.org/article/78d9256fe9d74d5c973c32eb64dc259e Atmospheric Chemistry and Physics, Vol 17, Iss 6, Pp 4283-4303 (2017) Physics QC1-999 Chemistry QD1-999 article 2017 ftdoajarticles https://doi.org/10.5194/acp-17-4283-2017 2022-12-31T09:17:52Z Spectral radiance measurements collected in nadir and sideward viewing directions by two airborne passive solar remote sensing instruments, the Spectral Modular Airborne Radiation measurement sysTem (SMART) and the Differential Optical Absorption Spectrometer (mini-DOAS), are used to compare the remote sensing results of cirrus optical thickness τ . The comparison is based on a sensitivity study using radiative transfer simulations (RTS) and on data obtained during three airborne field campaigns: the North Atlantic Rainfall VALidation (NARVAL) mission, the Mid-Latitude Cirrus Experiment (ML-CIRRUS) and the Aerosol, Cloud, Precipitation, and Radiation Interactions and Dynamics of Convective Cloud Systems (ACRIDICON) campaign. Radiative transfer simulations are used to quantify the sensitivity of measured upward radiance I with respect to τ , ice crystal effective radius r eff , viewing angle of the sensor θ V , spectral surface albedo α , and ice crystal shape. From the calculations it is concluded that sideward viewing measurements are generally better suited than radiance data from the nadir direction to retrieve τ of optically thin cirrus, especially at wavelengths larger than λ = 900 nm. Using sideward instead of nadir-directed spectral radiance measurements significantly improves the sensitivity and accuracy in retrieving τ , in particular for optically thin cirrus of τ ≤ 2. The comparison of retrievals of τ based on nadir and sideward viewing radiance measurements from SMART, mini-DOAS and independent estimates of τ from an additional active remote sensing instrument, the Water Vapor Lidar Experiment in Space (WALES), shows general agreement within the range of measurement uncertainties. For the selected example a mean τ of 0.54 ± 0.2 is derived from SMART, and 0.49 ± 0.2 by mini-DOAS nadir channels, while WALES obtained a mean value of τ = 0.32 ± 0.02 at 532 nm wavelength, respectively. The mean of τ derived from the sideward viewing mini-DOAS channels is 0.26 ± 0.2. For the few simultaneous measurements, ... Article in Journal/Newspaper North Atlantic narval narval Directory of Open Access Journals: DOAJ Articles Atmospheric Chemistry and Physics 17 6 4283 4303 |
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Physics QC1-999 Chemistry QD1-999 |
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Physics QC1-999 Chemistry QD1-999 K. Wolf A. Ehrlich T. Hüneke K. Pfeilsticker F. Werner M. Wirth M. Wendisch Potential of remote sensing of cirrus optical thickness by airborne spectral radiance measurements at different sideward viewing angles |
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Physics QC1-999 Chemistry QD1-999 |
description |
Spectral radiance measurements collected in nadir and sideward viewing directions by two airborne passive solar remote sensing instruments, the Spectral Modular Airborne Radiation measurement sysTem (SMART) and the Differential Optical Absorption Spectrometer (mini-DOAS), are used to compare the remote sensing results of cirrus optical thickness τ . The comparison is based on a sensitivity study using radiative transfer simulations (RTS) and on data obtained during three airborne field campaigns: the North Atlantic Rainfall VALidation (NARVAL) mission, the Mid-Latitude Cirrus Experiment (ML-CIRRUS) and the Aerosol, Cloud, Precipitation, and Radiation Interactions and Dynamics of Convective Cloud Systems (ACRIDICON) campaign. Radiative transfer simulations are used to quantify the sensitivity of measured upward radiance I with respect to τ , ice crystal effective radius r eff , viewing angle of the sensor θ V , spectral surface albedo α , and ice crystal shape. From the calculations it is concluded that sideward viewing measurements are generally better suited than radiance data from the nadir direction to retrieve τ of optically thin cirrus, especially at wavelengths larger than λ = 900 nm. Using sideward instead of nadir-directed spectral radiance measurements significantly improves the sensitivity and accuracy in retrieving τ , in particular for optically thin cirrus of τ ≤ 2. The comparison of retrievals of τ based on nadir and sideward viewing radiance measurements from SMART, mini-DOAS and independent estimates of τ from an additional active remote sensing instrument, the Water Vapor Lidar Experiment in Space (WALES), shows general agreement within the range of measurement uncertainties. For the selected example a mean τ of 0.54 ± 0.2 is derived from SMART, and 0.49 ± 0.2 by mini-DOAS nadir channels, while WALES obtained a mean value of τ = 0.32 ± 0.02 at 532 nm wavelength, respectively. The mean of τ derived from the sideward viewing mini-DOAS channels is 0.26 ± 0.2. For the few simultaneous measurements, ... |
format |
Article in Journal/Newspaper |
author |
K. Wolf A. Ehrlich T. Hüneke K. Pfeilsticker F. Werner M. Wirth M. Wendisch |
author_facet |
K. Wolf A. Ehrlich T. Hüneke K. Pfeilsticker F. Werner M. Wirth M. Wendisch |
author_sort |
K. Wolf |
title |
Potential of remote sensing of cirrus optical thickness by airborne spectral radiance measurements at different sideward viewing angles |
title_short |
Potential of remote sensing of cirrus optical thickness by airborne spectral radiance measurements at different sideward viewing angles |
title_full |
Potential of remote sensing of cirrus optical thickness by airborne spectral radiance measurements at different sideward viewing angles |
title_fullStr |
Potential of remote sensing of cirrus optical thickness by airborne spectral radiance measurements at different sideward viewing angles |
title_full_unstemmed |
Potential of remote sensing of cirrus optical thickness by airborne spectral radiance measurements at different sideward viewing angles |
title_sort |
potential of remote sensing of cirrus optical thickness by airborne spectral radiance measurements at different sideward viewing angles |
publisher |
Copernicus Publications |
publishDate |
2017 |
url |
https://doi.org/10.5194/acp-17-4283-2017 https://doaj.org/article/78d9256fe9d74d5c973c32eb64dc259e |
genre |
North Atlantic narval narval |
genre_facet |
North Atlantic narval narval |
op_source |
Atmospheric Chemistry and Physics, Vol 17, Iss 6, Pp 4283-4303 (2017) |
op_relation |
http://www.atmos-chem-phys.net/17/4283/2017/acp-17-4283-2017.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 1680-7316 1680-7324 doi:10.5194/acp-17-4283-2017 https://doaj.org/article/78d9256fe9d74d5c973c32eb64dc259e |
op_doi |
https://doi.org/10.5194/acp-17-4283-2017 |
container_title |
Atmospheric Chemistry and Physics |
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17 |
container_issue |
6 |
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4283 |
op_container_end_page |
4303 |
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1766135558878265344 |