STEREO DERIVED CLOUD TOP HEIGHT CLIMATOLOGY OVER GREENLAND FROM 20 YEARS OF THE ALONG TRACK SCANNING RADIOMETER (ATSR) INSTRUMENTS
Current algorithms for the determination of cloud top height and cloud fraction in Polar Regions tend to provide unreliable results, particularly in the presence of isothermal conditions within the atmosphere. Alternative methods to determine cloud top heights in such regions effectively, from space...
Published in: | The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences |
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ftdoajarticles:oai:doaj.org/article:f3231a248ea648cab464aa8b3102bd1e 2023-05-15T16:28:28+02:00 STEREO DERIVED CLOUD TOP HEIGHT CLIMATOLOGY OVER GREENLAND FROM 20 YEARS OF THE ALONG TRACK SCANNING RADIOMETER (ATSR) INSTRUMENTS D. Fisher J.-P. Muller 2012-07-01T00:00:00Z https://doi.org/10.5194/isprsarchives-XXXIX-B8-109-2012 https://doaj.org/article/f3231a248ea648cab464aa8b3102bd1e EN eng Copernicus Publications http://www.int-arch-photogramm-remote-sens-spatial-inf-sci.net/XXXIX-B8/109/2012/isprsarchives-XXXIX-B8-109-2012.pdf https://doaj.org/toc/1682-1750 https://doaj.org/toc/2194-9034 1682-1750 2194-9034 doi:10.5194/isprsarchives-XXXIX-B8-109-2012 https://doaj.org/article/f3231a248ea648cab464aa8b3102bd1e The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXIX-B8, Pp 109-113 (2012) Technology T Engineering (General). Civil engineering (General) TA1-2040 Applied optics. Photonics TA1501-1820 article 2012 ftdoajarticles https://doi.org/10.5194/isprsarchives-XXXIX-B8-109-2012 2022-12-31T01:04:13Z Current algorithms for the determination of cloud top height and cloud fraction in Polar Regions tend to provide unreliable results, particularly in the presence of isothermal conditions within the atmosphere. Alternative methods to determine cloud top heights in such regions effectively, from space borne sensors, are currently limited to stereo-photogrammetry and active sensing methods, such as LiDAR. Here we apply the modified census transform to one month of AATSR stereo data from June 2008. AATSR is unique in that it is the only space borne stereo capable instrument providing data continuously in both the visible, near infrared and thermal channels. This allows for year round imaging of the poles and therefore year round cloud top height and cloud fraction estimation. We attempt a preliminary validation of the stereo retrieved cloud top height measurements from AATSR against collocated cloud height measurements from the CALIOP LiDAR instrument. CALIOP provides an excellent validation tool due to its excellent height resolution of between 30-60 meters. In this validation, a pair of collocated swaths is assessed with a total of 154 inter-comparisons; the results show that AATSR correlates well with CALIOP cloud base layers with an R 2 score of 0.71. However, in all cases AATSR appears to be underestimating the cloud top height compared to CALIOP, the causes for this are currently not fully understood and more extensive inter-comparisons are required. Once validation is completed a processing chain is in place to process the entire ATSR time-series data generating a 20 year cloud top height dataset for Greenland. Article in Journal/Newspaper Greenland Directory of Open Access Journals: DOAJ Articles Greenland The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XXXIX-B8 109 113 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Technology T Engineering (General). Civil engineering (General) TA1-2040 Applied optics. Photonics TA1501-1820 |
spellingShingle |
Technology T Engineering (General). Civil engineering (General) TA1-2040 Applied optics. Photonics TA1501-1820 D. Fisher J.-P. Muller STEREO DERIVED CLOUD TOP HEIGHT CLIMATOLOGY OVER GREENLAND FROM 20 YEARS OF THE ALONG TRACK SCANNING RADIOMETER (ATSR) INSTRUMENTS |
topic_facet |
Technology T Engineering (General). Civil engineering (General) TA1-2040 Applied optics. Photonics TA1501-1820 |
description |
Current algorithms for the determination of cloud top height and cloud fraction in Polar Regions tend to provide unreliable results, particularly in the presence of isothermal conditions within the atmosphere. Alternative methods to determine cloud top heights in such regions effectively, from space borne sensors, are currently limited to stereo-photogrammetry and active sensing methods, such as LiDAR. Here we apply the modified census transform to one month of AATSR stereo data from June 2008. AATSR is unique in that it is the only space borne stereo capable instrument providing data continuously in both the visible, near infrared and thermal channels. This allows for year round imaging of the poles and therefore year round cloud top height and cloud fraction estimation. We attempt a preliminary validation of the stereo retrieved cloud top height measurements from AATSR against collocated cloud height measurements from the CALIOP LiDAR instrument. CALIOP provides an excellent validation tool due to its excellent height resolution of between 30-60 meters. In this validation, a pair of collocated swaths is assessed with a total of 154 inter-comparisons; the results show that AATSR correlates well with CALIOP cloud base layers with an R 2 score of 0.71. However, in all cases AATSR appears to be underestimating the cloud top height compared to CALIOP, the causes for this are currently not fully understood and more extensive inter-comparisons are required. Once validation is completed a processing chain is in place to process the entire ATSR time-series data generating a 20 year cloud top height dataset for Greenland. |
format |
Article in Journal/Newspaper |
author |
D. Fisher J.-P. Muller |
author_facet |
D. Fisher J.-P. Muller |
author_sort |
D. Fisher |
title |
STEREO DERIVED CLOUD TOP HEIGHT CLIMATOLOGY OVER GREENLAND FROM 20 YEARS OF THE ALONG TRACK SCANNING RADIOMETER (ATSR) INSTRUMENTS |
title_short |
STEREO DERIVED CLOUD TOP HEIGHT CLIMATOLOGY OVER GREENLAND FROM 20 YEARS OF THE ALONG TRACK SCANNING RADIOMETER (ATSR) INSTRUMENTS |
title_full |
STEREO DERIVED CLOUD TOP HEIGHT CLIMATOLOGY OVER GREENLAND FROM 20 YEARS OF THE ALONG TRACK SCANNING RADIOMETER (ATSR) INSTRUMENTS |
title_fullStr |
STEREO DERIVED CLOUD TOP HEIGHT CLIMATOLOGY OVER GREENLAND FROM 20 YEARS OF THE ALONG TRACK SCANNING RADIOMETER (ATSR) INSTRUMENTS |
title_full_unstemmed |
STEREO DERIVED CLOUD TOP HEIGHT CLIMATOLOGY OVER GREENLAND FROM 20 YEARS OF THE ALONG TRACK SCANNING RADIOMETER (ATSR) INSTRUMENTS |
title_sort |
stereo derived cloud top height climatology over greenland from 20 years of the along track scanning radiometer (atsr) instruments |
publisher |
Copernicus Publications |
publishDate |
2012 |
url |
https://doi.org/10.5194/isprsarchives-XXXIX-B8-109-2012 https://doaj.org/article/f3231a248ea648cab464aa8b3102bd1e |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland |
genre_facet |
Greenland |
op_source |
The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXIX-B8, Pp 109-113 (2012) |
op_relation |
http://www.int-arch-photogramm-remote-sens-spatial-inf-sci.net/XXXIX-B8/109/2012/isprsarchives-XXXIX-B8-109-2012.pdf https://doaj.org/toc/1682-1750 https://doaj.org/toc/2194-9034 1682-1750 2194-9034 doi:10.5194/isprsarchives-XXXIX-B8-109-2012 https://doaj.org/article/f3231a248ea648cab464aa8b3102bd1e |
op_doi |
https://doi.org/10.5194/isprsarchives-XXXIX-B8-109-2012 |
container_title |
The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences |
container_volume |
XXXIX-B8 |
container_start_page |
109 |
op_container_end_page |
113 |
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1766018127502508032 |