Satellite-retrieval and modeling of glacier mass balance
In this research project we use satellite measurements to infer the mean specific mass balance (Bm) of glaciers. Vatnajökull, the largest ice cap in Europe, is being used as a test-case because this ice cap has often been studied. Only one aspect of Vatnajökull has not been investigated so far, and...
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2002
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ftunivutrecht:oai:dspace.library.uu.nl:1874/677 2023-07-23T04:19:24+02:00 Satellite-retrieval and modeling of glacier mass balance Ruyter de Wildt, Martijn Sybren de 2002-07-07 application/pdf https://dspace.library.uu.nl/handle/1874/677 en eng https://dspace.library.uu.nl/handle/1874/677 info:eu-repo/semantics/OpenAccess Natuur- en Sterrenkunde AVHRR climate change equilibrium line glacier ice cap Iceland mass balance remote sensing SAR Dissertation 2002 ftunivutrecht 2023-07-01T22:45:51Z In this research project we use satellite measurements to infer the mean specific mass balance (Bm) of glaciers. Vatnajökull, the largest ice cap in Europe, is being used as a test-case because this ice cap has often been studied. Only one aspect of Vatnajökull has not been investigated so far, and that is the relation between its mass balance and climatological conditions. We therefore also construct a mass balance model, the results of which can be compared to the satellite images. On Vatnajökull an extensive meteorological experiment took place in the summer of 1996, and the dataset collected during this experiment can be used for validation of the model. The mass balance model is calibrated with in situ measurements. We find that the incoming longwave radiation is best modeled as a function of meteorological variables in the free atmosphere just above the relatively thin katabatic layer. Also, the ratio of changes in the 2 m temperature to changes in the free atmospheric temperature (the climate sensitivity) is smaller than 1. Horizontal precipitation gradients over Vatnajökull are large, which results in a strongly varying sensitivity to external temperature changes over the ice cap. Local climatic conditions thus highly determine the mass balance and its sensitivity. From the mass balance model we construct a Seasonal Sensitivity Characteristic (SSC) of Vatnajökull, which consists of the sensitivity of Bm to monthly perturbations in temperature and precipitation. Temperature sensitivities are high in summer and nearly zero in winter, while precipitation sensitivities are high in winter and low in summer. With the SSC we reconstruct the mass balance of Vatnajökull since 1825. The results for two Icelandic glaciers correlate very well with mass balance records that are extracted from length records with a linear inverse model. For the south of Vatnajökull we find that after 1900, the length record is well explained by temperature variations alone, while another Icelandic glacier (S¢lheimajökull) was also ... Doctoral or Postdoctoral Thesis glacier Ice cap Iceland Vatnajökull Utrecht University Repository Line Glacier ENVELOPE(167.833,167.833,-72.983,-72.983) Vatnajökull ENVELOPE(-16.823,-16.823,64.420,64.420) |
institution |
Open Polar |
collection |
Utrecht University Repository |
op_collection_id |
ftunivutrecht |
language |
English |
topic |
Natuur- en Sterrenkunde AVHRR climate change equilibrium line glacier ice cap Iceland mass balance remote sensing SAR |
spellingShingle |
Natuur- en Sterrenkunde AVHRR climate change equilibrium line glacier ice cap Iceland mass balance remote sensing SAR Ruyter de Wildt, Martijn Sybren de Satellite-retrieval and modeling of glacier mass balance |
topic_facet |
Natuur- en Sterrenkunde AVHRR climate change equilibrium line glacier ice cap Iceland mass balance remote sensing SAR |
description |
In this research project we use satellite measurements to infer the mean specific mass balance (Bm) of glaciers. Vatnajökull, the largest ice cap in Europe, is being used as a test-case because this ice cap has often been studied. Only one aspect of Vatnajökull has not been investigated so far, and that is the relation between its mass balance and climatological conditions. We therefore also construct a mass balance model, the results of which can be compared to the satellite images. On Vatnajökull an extensive meteorological experiment took place in the summer of 1996, and the dataset collected during this experiment can be used for validation of the model. The mass balance model is calibrated with in situ measurements. We find that the incoming longwave radiation is best modeled as a function of meteorological variables in the free atmosphere just above the relatively thin katabatic layer. Also, the ratio of changes in the 2 m temperature to changes in the free atmospheric temperature (the climate sensitivity) is smaller than 1. Horizontal precipitation gradients over Vatnajökull are large, which results in a strongly varying sensitivity to external temperature changes over the ice cap. Local climatic conditions thus highly determine the mass balance and its sensitivity. From the mass balance model we construct a Seasonal Sensitivity Characteristic (SSC) of Vatnajökull, which consists of the sensitivity of Bm to monthly perturbations in temperature and precipitation. Temperature sensitivities are high in summer and nearly zero in winter, while precipitation sensitivities are high in winter and low in summer. With the SSC we reconstruct the mass balance of Vatnajökull since 1825. The results for two Icelandic glaciers correlate very well with mass balance records that are extracted from length records with a linear inverse model. For the south of Vatnajökull we find that after 1900, the length record is well explained by temperature variations alone, while another Icelandic glacier (S¢lheimajökull) was also ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Ruyter de Wildt, Martijn Sybren de |
author_facet |
Ruyter de Wildt, Martijn Sybren de |
author_sort |
Ruyter de Wildt, Martijn Sybren de |
title |
Satellite-retrieval and modeling of glacier mass balance |
title_short |
Satellite-retrieval and modeling of glacier mass balance |
title_full |
Satellite-retrieval and modeling of glacier mass balance |
title_fullStr |
Satellite-retrieval and modeling of glacier mass balance |
title_full_unstemmed |
Satellite-retrieval and modeling of glacier mass balance |
title_sort |
satellite-retrieval and modeling of glacier mass balance |
publishDate |
2002 |
url |
https://dspace.library.uu.nl/handle/1874/677 |
long_lat |
ENVELOPE(167.833,167.833,-72.983,-72.983) ENVELOPE(-16.823,-16.823,64.420,64.420) |
geographic |
Line Glacier Vatnajökull |
geographic_facet |
Line Glacier Vatnajökull |
genre |
glacier Ice cap Iceland Vatnajökull |
genre_facet |
glacier Ice cap Iceland Vatnajökull |
op_relation |
https://dspace.library.uu.nl/handle/1874/677 |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1772182407221346304 |