Optical Studies of the Antarctic Glacio-Oceanic System
The Antarctic system comprises of the continent itself, Antarctica, and the ocean surrounding it, the Southern Ocean. The system has an important part in the global climate due to its size, its high latitude location and the negative radiation balance of its large ice sheets. Antarctica has also bee...
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ftunivhelsihelda:oai:helda.helsinki.fi:10138/23171 2024-04-21T07:47:57+00:00 Optical Studies of the Antarctic Glacio-Oceanic System Rasmus, Kai University of Helsinki, Faculty of Science, Department of Physics Finnish Environment Institute (SYKE), Jyväskylä Office Helsingin yliopisto, matemaattis-luonnontieteellinen tiedekunta, fysiikan laitos Helsingfors universitet, matematisk-naturvetenskapliga fakulteten, institutionen för fysik Bøggild, Carl Huttula, Timo Leppäranta, Matti 2010-11-25T14:09:07Z 68 application/pdf http://hdl.handle.net/10138/23171 eng eng Helsingin yliopisto Helsingfors universitet University of Helsinki Report series in Geophysics 62 978-952-10-5635-2 0355-8630 978-952-10-5636-9 http://hdl.handle.net/10138/23171 URN:ISBN:978-952-10-5636-9 This publication is copyrighted. You may download, display and print it for Your own personal use. Commercial use is prohibited. Julkaisu on tekijänoikeussäännösten alainen. Teosta voi lukea ja tulostaa henkilökohtaista käyttöä varten. Käyttö kaupallisiin tarkoituksiin on kielletty. Publikationen är skyddad av upphovsrätten. Den får läsas och skrivas ut för personligt bruk. Användning i kommersiellt syfte är förbjuden. geofysiikka Doctoral thesis Väitöskirja Doctoral dissertation (article-based) Artikkeliväitöskirja Artikelavhandling Text doctoralThesis 2010 ftunivhelsihelda 2024-03-27T17:50:30Z The Antarctic system comprises of the continent itself, Antarctica, and the ocean surrounding it, the Southern Ocean. The system has an important part in the global climate due to its size, its high latitude location and the negative radiation balance of its large ice sheets. Antarctica has also been in focus for several decades due to increased ultraviolet (UV) levels caused by stratospheric ozone depletion, and the disintegration of its ice shelves. In this study, measurements were made during three Austral summers to study the optical properties of the Antarctic system and to produce radiation information for additional modeling studies. These are related to specific phenomena found in the system. During the summer of 1997-1998, measurements of beam absorption and beam attenuation coefficients, and downwelling and upwelling irradiance were made in the Southern Ocean along a S-N transect at 6°E. The attenuation of photosynthetically active radiation (PAR) was calculated and used together with hydrographic measurements to judge whether the phytoplankton in the investigated areas of the Southern Ocean are light limited. By using the Kirk formula the diffuse attenuation coefficient was linked to the absorption and scattering coefficients. The diffuse attenuation coefficients (Kpar) for PAR were found to vary between 0.03 and 0.09 1/m. Using the values for KPAR and the definition of the Sverdrup critical depth, the studied Southern Ocean plankton systems were found not to be light limited. Variabilities in the spectral and total albedo of snow were studied in the Queen Maud Land region of Antarctica during the summers of 1999-2000 and 2000-2001. The measurement areas were the vicinity of the South African Antarctic research station SANAE 4, and a traverse near the Finnish Antarctic research station Aboa. The midday mean total albedos for snow were between 0.83, for clear skies, and 0.86, for overcast skies, at Aboa and between 0.81 and 0.83 for SANAE 4. The mean spectral albedo levels at Aboa and SANAE 4 were very ... Doctoral or Postdoctoral Thesis Antarc* Antarctic Antarctica Ice Shelves Queen Maud Land Southern Ocean HELDA – University of Helsinki Open Repository |
institution |
Open Polar |
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HELDA – University of Helsinki Open Repository |
op_collection_id |
ftunivhelsihelda |
language |
English |
topic |
geofysiikka |
spellingShingle |
geofysiikka Rasmus, Kai Optical Studies of the Antarctic Glacio-Oceanic System |
topic_facet |
geofysiikka |
description |
The Antarctic system comprises of the continent itself, Antarctica, and the ocean surrounding it, the Southern Ocean. The system has an important part in the global climate due to its size, its high latitude location and the negative radiation balance of its large ice sheets. Antarctica has also been in focus for several decades due to increased ultraviolet (UV) levels caused by stratospheric ozone depletion, and the disintegration of its ice shelves. In this study, measurements were made during three Austral summers to study the optical properties of the Antarctic system and to produce radiation information for additional modeling studies. These are related to specific phenomena found in the system. During the summer of 1997-1998, measurements of beam absorption and beam attenuation coefficients, and downwelling and upwelling irradiance were made in the Southern Ocean along a S-N transect at 6°E. The attenuation of photosynthetically active radiation (PAR) was calculated and used together with hydrographic measurements to judge whether the phytoplankton in the investigated areas of the Southern Ocean are light limited. By using the Kirk formula the diffuse attenuation coefficient was linked to the absorption and scattering coefficients. The diffuse attenuation coefficients (Kpar) for PAR were found to vary between 0.03 and 0.09 1/m. Using the values for KPAR and the definition of the Sverdrup critical depth, the studied Southern Ocean plankton systems were found not to be light limited. Variabilities in the spectral and total albedo of snow were studied in the Queen Maud Land region of Antarctica during the summers of 1999-2000 and 2000-2001. The measurement areas were the vicinity of the South African Antarctic research station SANAE 4, and a traverse near the Finnish Antarctic research station Aboa. The midday mean total albedos for snow were between 0.83, for clear skies, and 0.86, for overcast skies, at Aboa and between 0.81 and 0.83 for SANAE 4. The mean spectral albedo levels at Aboa and SANAE 4 were very ... |
author2 |
University of Helsinki, Faculty of Science, Department of Physics Finnish Environment Institute (SYKE), Jyväskylä Office Helsingin yliopisto, matemaattis-luonnontieteellinen tiedekunta, fysiikan laitos Helsingfors universitet, matematisk-naturvetenskapliga fakulteten, institutionen för fysik Bøggild, Carl Huttula, Timo Leppäranta, Matti |
format |
Doctoral or Postdoctoral Thesis |
author |
Rasmus, Kai |
author_facet |
Rasmus, Kai |
author_sort |
Rasmus, Kai |
title |
Optical Studies of the Antarctic Glacio-Oceanic System |
title_short |
Optical Studies of the Antarctic Glacio-Oceanic System |
title_full |
Optical Studies of the Antarctic Glacio-Oceanic System |
title_fullStr |
Optical Studies of the Antarctic Glacio-Oceanic System |
title_full_unstemmed |
Optical Studies of the Antarctic Glacio-Oceanic System |
title_sort |
optical studies of the antarctic glacio-oceanic system |
publisher |
Helsingin yliopisto |
publishDate |
2010 |
url |
http://hdl.handle.net/10138/23171 |
genre |
Antarc* Antarctic Antarctica Ice Shelves Queen Maud Land Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctica Ice Shelves Queen Maud Land Southern Ocean |
op_relation |
Report series in Geophysics 62 978-952-10-5635-2 0355-8630 978-952-10-5636-9 http://hdl.handle.net/10138/23171 URN:ISBN:978-952-10-5636-9 |
op_rights |
This publication is copyrighted. You may download, display and print it for Your own personal use. Commercial use is prohibited. Julkaisu on tekijänoikeussäännösten alainen. Teosta voi lukea ja tulostaa henkilökohtaista käyttöä varten. Käyttö kaupallisiin tarkoituksiin on kielletty. Publikationen är skyddad av upphovsrätten. Den får läsas och skrivas ut för personligt bruk. Användning i kommersiellt syfte är förbjuden. |
_version_ |
1796947601368547328 |