Aerosol Remote Sensing in Polar Regions
Multi-year sets of ground-based sun-photometer measurements conducted at 12 Arctic sites and 9 Antarctic sites were examined to determine daily mean values of aerosol optical thickness tau(lambda) at visible and near-infrared wavelengths, from which best-fit values of ngstrm's exponent alpha we...
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ftnasantrs:oai:casi.ntrs.nasa.gov:20150021517 2023-05-15T13:59:55+02:00 Aerosol Remote Sensing in Polar Regions Lupi, Angelo Ritter, Christoph Tomasi, Claudio Stone, Robert S. Kokhanovsky, Alexander A. Nyeki, Stephan O'Neill, Norman T. Smirnov, Alexander Wehrli, Christoph Holben, Brent N. Unclassified, Unlimited, Publicly available November 10, 2014 application/pdf http://hdl.handle.net/2060/20150021517 unknown Document ID: 20150021517 http://hdl.handle.net/2060/20150021517 Copyright, Distribution as joint owner in the copyright CASI Earth Resources and Remote Sensing GSFC-E-DAA-TN22577 2014 ftnasantrs 2019-07-21T06:09:14Z Multi-year sets of ground-based sun-photometer measurements conducted at 12 Arctic sites and 9 Antarctic sites were examined to determine daily mean values of aerosol optical thickness tau(lambda) at visible and near-infrared wavelengths, from which best-fit values of ngstrm's exponent alpha were calculated. Analyzing these data, the monthly mean values of tau(0.50 micrometers) and alpha and the relative frequency histograms of the daily mean values of both parameters were determined for winter-spring and summer-autumn in the Arctic and for austral summer in Antarctica. The Arctic and Antarctic covariance plots of the seasonal median values of alpha versus tau(0.50 micrometers) showed: (i) a considerable increase in tau(0.50 micrometers) for the Arctic aerosol from summer to winter-spring, without marked changes in alpha; and (ii) a marked increase in tau(0.50 micrometer) passing from the Antarctic Plateau to coastal sites, whereas alpha decreased considerably due to the larger fraction of sea-salt aerosol. Good agreement was found when comparing ground-based sun-photometer measurements of tau(lambda) and alpha at Arctic and Antarctic coastal sites with Microtops measurements conducted during numerous AERONET/MAN cruises from 2006 to 2013 in three Arctic Ocean sectors and in coastal and off-shore regions of the Southern Atlantic, Pacific, and Indian Oceans, and the Antarctic Peninsula. Lidar measurements were also examined to characterize vertical profiles of the aerosol backscattering coefficient measured throughout the year at Ny-lesund. Satellite-based MODIS, MISR, and AATSR retrievals of tau(lambda) over large parts of the oceanic polar regions during spring and summer were in close agreement with ship-borne and coastal ground-based sun-photometer measurements. An overview of the chemical composition of mode particles is also presented, based on in-situ measurements at Arctic and Antarctic sites. Fourteen log-normal aerosol number size-distributions were defined to represent the average features of nuclei, accumulation and coarse mode particles for Arctic haze, summer background aerosol, Asian dust and boreal forest fire smoke, and for various background austral summer aerosol types at coastal and high-altitude Antarctic sites. The main columnar aerosol optical characteristics were determined for all 14 particle modes, based on in-situ measurements of the scattering and absorption coefficients. Diurnally averaged direct aerosol-induced radiative forcing and efficiency were calculated for a set of multimodal aerosol extinction models, using various Bidirectional Reflectance Distribution Function models over vegetation-covered, oceanic and snow-covered surfaces. These gave a reliable measure of the pronounced effects of aerosols on the radiation balance of the surface-atmosphere system over polar regions. Other/Unknown Material Antarc* Antarctic Antarctic Peninsula Antarctica Arctic Arctic Ocean NASA Technical Reports Server (NTRS) Antarctic Antarctic Peninsula Arctic Arctic Ocean Austral Indian Lambda ENVELOPE(-62.983,-62.983,-64.300,-64.300) Lesund ENVELOPE(8.470,8.470,63.331,63.331) Pacific The Antarctic |
institution |
Open Polar |
collection |
NASA Technical Reports Server (NTRS) |
op_collection_id |
ftnasantrs |
language |
unknown |
topic |
Earth Resources and Remote Sensing |
spellingShingle |
Earth Resources and Remote Sensing Lupi, Angelo Ritter, Christoph Tomasi, Claudio Stone, Robert S. Kokhanovsky, Alexander A. Nyeki, Stephan O'Neill, Norman T. Smirnov, Alexander Wehrli, Christoph Holben, Brent N. Aerosol Remote Sensing in Polar Regions |
topic_facet |
Earth Resources and Remote Sensing |
description |
Multi-year sets of ground-based sun-photometer measurements conducted at 12 Arctic sites and 9 Antarctic sites were examined to determine daily mean values of aerosol optical thickness tau(lambda) at visible and near-infrared wavelengths, from which best-fit values of ngstrm's exponent alpha were calculated. Analyzing these data, the monthly mean values of tau(0.50 micrometers) and alpha and the relative frequency histograms of the daily mean values of both parameters were determined for winter-spring and summer-autumn in the Arctic and for austral summer in Antarctica. The Arctic and Antarctic covariance plots of the seasonal median values of alpha versus tau(0.50 micrometers) showed: (i) a considerable increase in tau(0.50 micrometers) for the Arctic aerosol from summer to winter-spring, without marked changes in alpha; and (ii) a marked increase in tau(0.50 micrometer) passing from the Antarctic Plateau to coastal sites, whereas alpha decreased considerably due to the larger fraction of sea-salt aerosol. Good agreement was found when comparing ground-based sun-photometer measurements of tau(lambda) and alpha at Arctic and Antarctic coastal sites with Microtops measurements conducted during numerous AERONET/MAN cruises from 2006 to 2013 in three Arctic Ocean sectors and in coastal and off-shore regions of the Southern Atlantic, Pacific, and Indian Oceans, and the Antarctic Peninsula. Lidar measurements were also examined to characterize vertical profiles of the aerosol backscattering coefficient measured throughout the year at Ny-lesund. Satellite-based MODIS, MISR, and AATSR retrievals of tau(lambda) over large parts of the oceanic polar regions during spring and summer were in close agreement with ship-borne and coastal ground-based sun-photometer measurements. An overview of the chemical composition of mode particles is also presented, based on in-situ measurements at Arctic and Antarctic sites. Fourteen log-normal aerosol number size-distributions were defined to represent the average features of nuclei, accumulation and coarse mode particles for Arctic haze, summer background aerosol, Asian dust and boreal forest fire smoke, and for various background austral summer aerosol types at coastal and high-altitude Antarctic sites. The main columnar aerosol optical characteristics were determined for all 14 particle modes, based on in-situ measurements of the scattering and absorption coefficients. Diurnally averaged direct aerosol-induced radiative forcing and efficiency were calculated for a set of multimodal aerosol extinction models, using various Bidirectional Reflectance Distribution Function models over vegetation-covered, oceanic and snow-covered surfaces. These gave a reliable measure of the pronounced effects of aerosols on the radiation balance of the surface-atmosphere system over polar regions. |
format |
Other/Unknown Material |
author |
Lupi, Angelo Ritter, Christoph Tomasi, Claudio Stone, Robert S. Kokhanovsky, Alexander A. Nyeki, Stephan O'Neill, Norman T. Smirnov, Alexander Wehrli, Christoph Holben, Brent N. |
author_facet |
Lupi, Angelo Ritter, Christoph Tomasi, Claudio Stone, Robert S. Kokhanovsky, Alexander A. Nyeki, Stephan O'Neill, Norman T. Smirnov, Alexander Wehrli, Christoph Holben, Brent N. |
author_sort |
Lupi, Angelo |
title |
Aerosol Remote Sensing in Polar Regions |
title_short |
Aerosol Remote Sensing in Polar Regions |
title_full |
Aerosol Remote Sensing in Polar Regions |
title_fullStr |
Aerosol Remote Sensing in Polar Regions |
title_full_unstemmed |
Aerosol Remote Sensing in Polar Regions |
title_sort |
aerosol remote sensing in polar regions |
publishDate |
2014 |
url |
http://hdl.handle.net/2060/20150021517 |
op_coverage |
Unclassified, Unlimited, Publicly available |
long_lat |
ENVELOPE(-62.983,-62.983,-64.300,-64.300) ENVELOPE(8.470,8.470,63.331,63.331) |
geographic |
Antarctic Antarctic Peninsula Arctic Arctic Ocean Austral Indian Lambda Lesund Pacific The Antarctic |
geographic_facet |
Antarctic Antarctic Peninsula Arctic Arctic Ocean Austral Indian Lambda Lesund Pacific The Antarctic |
genre |
Antarc* Antarctic Antarctic Peninsula Antarctica Arctic Arctic Ocean |
genre_facet |
Antarc* Antarctic Antarctic Peninsula Antarctica Arctic Arctic Ocean |
op_source |
CASI |
op_relation |
Document ID: 20150021517 http://hdl.handle.net/2060/20150021517 |
op_rights |
Copyright, Distribution as joint owner in the copyright |
_version_ |
1766268839135281152 |