The importance of accurate glacier albedo for estimates of surface mass balance on Vatnajökull: evaluating the surface energy budget in a regional climate model with automatic weather station observations

A simulation of the surface climate of Vatnajökull ice cap, Iceland, carried out with the regional climate model HIRHAM5 for the period 1980–2014, is used to estimate the evolution of the glacier surface mass balance (SMB). This simulation uses a new snow albedo parameterization that allows albedo t...

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Published in:The Cryosphere
Main Authors: Schmidt, Louise Steffensen, Aðalgeirsdóttir, Guðfinna, Guðmundsson, Sverrir, Langen, Peter L., Pálsson, Finnur, Mottram, Ruth, Gascoin, Simon, Björnsson, Helgi
Format: Article in Journal/Newspaper
Language:English
Published: Copernicus Publications 2017
Subjects:
Online Access:https://doi.org/10.5194/tc-11-1665-2017
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spelling ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00009599 2023-05-15T16:21:47+02:00 The importance of accurate glacier albedo for estimates of surface mass balance on Vatnajökull: evaluating the surface energy budget in a regional climate model with automatic weather station observations Schmidt, Louise Steffensen Aðalgeirsdóttir, Guðfinna Guðmundsson, Sverrir Langen, Peter L. Pálsson, Finnur Mottram, Ruth Gascoin, Simon Björnsson, Helgi 2017-07 electronic https://doi.org/10.5194/tc-11-1665-2017 https://noa.gwlb.de/receive/cop_mods_00009599 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00009556/tc-11-1665-2017.pdf https://tc.copernicus.org/articles/11/1665/2017/tc-11-1665-2017.pdf eng eng Copernicus Publications The Cryosphere -- ˜Theœ Cryosphere -- http://www.bibliothek.uni-regensburg.de/ezeit/?2393169 -- http://www.the-cryosphere.net/ -- 1994-0424 https://doi.org/10.5194/tc-11-1665-2017 https://noa.gwlb.de/receive/cop_mods_00009599 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00009556/tc-11-1665-2017.pdf https://tc.copernicus.org/articles/11/1665/2017/tc-11-1665-2017.pdf uneingeschränkt info:eu-repo/semantics/openAccess article Verlagsveröffentlichung article Text doc-type:article 2017 ftnonlinearchiv https://doi.org/10.5194/tc-11-1665-2017 2022-02-08T22:57:27Z A simulation of the surface climate of Vatnajökull ice cap, Iceland, carried out with the regional climate model HIRHAM5 for the period 1980–2014, is used to estimate the evolution of the glacier surface mass balance (SMB). This simulation uses a new snow albedo parameterization that allows albedo to exponentially decay with time and is surface temperature dependent. The albedo scheme utilizes a new background map of the ice albedo created from observed MODIS data. The simulation is evaluated against observed daily values of weather parameters from five automatic weather stations (AWSs) from the period 2001–2014, as well as in situ SMB measurements from the period 1995–2014. The model agrees well with observations at the AWS sites, albeit with a general underestimation of the net radiation. This is due to an underestimation of the incoming radiation and a general overestimation of the albedo. The average modelled albedo is overestimated in the ablation zone, which we attribute to an overestimation of the thickness of the snow layer and not taking the surface darkening from dirt and volcanic ash deposition during dust storms and volcanic eruptions into account. A comparison with the specific summer, winter, and net mass balance for the whole of Vatnajökull (1995–2014) shows a good overall fit during the summer, with a small mass balance underestimation of 0.04 m w.e. on average, whereas the winter mass balance is overestimated by on average 0.5 m w.e. due to too large precipitation at the highest areas of the ice cap. A simple correction of the accumulation at the highest points of the glacier reduces this to 0.15 m w.e. Here, we use HIRHAM5 to simulate the evolution of the SMB of Vatnajökull for the period 1981–2014 and show that the model provides a reasonable representation of the SMB for this period. However, a major source of uncertainty in the representation of the SMB is the representation of the albedo, and processes currently not accounted for in RCMs, such as dust storms, are an important source of uncertainty in estimates of snow melt rate. Article in Journal/Newspaper glacier Ice cap Iceland The Cryosphere Vatnajökull Niedersächsisches Online-Archiv NOA Vatnajökull ENVELOPE(-16.823,-16.823,64.420,64.420) The Cryosphere 11 4 1665 1684
institution Open Polar
collection Niedersächsisches Online-Archiv NOA
op_collection_id ftnonlinearchiv
language English
topic article
Verlagsveröffentlichung
spellingShingle article
Verlagsveröffentlichung
Schmidt, Louise Steffensen
Aðalgeirsdóttir, Guðfinna
Guðmundsson, Sverrir
Langen, Peter L.
Pálsson, Finnur
Mottram, Ruth
Gascoin, Simon
Björnsson, Helgi
The importance of accurate glacier albedo for estimates of surface mass balance on Vatnajökull: evaluating the surface energy budget in a regional climate model with automatic weather station observations
topic_facet article
Verlagsveröffentlichung
description A simulation of the surface climate of Vatnajökull ice cap, Iceland, carried out with the regional climate model HIRHAM5 for the period 1980–2014, is used to estimate the evolution of the glacier surface mass balance (SMB). This simulation uses a new snow albedo parameterization that allows albedo to exponentially decay with time and is surface temperature dependent. The albedo scheme utilizes a new background map of the ice albedo created from observed MODIS data. The simulation is evaluated against observed daily values of weather parameters from five automatic weather stations (AWSs) from the period 2001–2014, as well as in situ SMB measurements from the period 1995–2014. The model agrees well with observations at the AWS sites, albeit with a general underestimation of the net radiation. This is due to an underestimation of the incoming radiation and a general overestimation of the albedo. The average modelled albedo is overestimated in the ablation zone, which we attribute to an overestimation of the thickness of the snow layer and not taking the surface darkening from dirt and volcanic ash deposition during dust storms and volcanic eruptions into account. A comparison with the specific summer, winter, and net mass balance for the whole of Vatnajökull (1995–2014) shows a good overall fit during the summer, with a small mass balance underestimation of 0.04 m w.e. on average, whereas the winter mass balance is overestimated by on average 0.5 m w.e. due to too large precipitation at the highest areas of the ice cap. A simple correction of the accumulation at the highest points of the glacier reduces this to 0.15 m w.e. Here, we use HIRHAM5 to simulate the evolution of the SMB of Vatnajökull for the period 1981–2014 and show that the model provides a reasonable representation of the SMB for this period. However, a major source of uncertainty in the representation of the SMB is the representation of the albedo, and processes currently not accounted for in RCMs, such as dust storms, are an important source of uncertainty in estimates of snow melt rate.
format Article in Journal/Newspaper
author Schmidt, Louise Steffensen
Aðalgeirsdóttir, Guðfinna
Guðmundsson, Sverrir
Langen, Peter L.
Pálsson, Finnur
Mottram, Ruth
Gascoin, Simon
Björnsson, Helgi
author_facet Schmidt, Louise Steffensen
Aðalgeirsdóttir, Guðfinna
Guðmundsson, Sverrir
Langen, Peter L.
Pálsson, Finnur
Mottram, Ruth
Gascoin, Simon
Björnsson, Helgi
author_sort Schmidt, Louise Steffensen
title The importance of accurate glacier albedo for estimates of surface mass balance on Vatnajökull: evaluating the surface energy budget in a regional climate model with automatic weather station observations
title_short The importance of accurate glacier albedo for estimates of surface mass balance on Vatnajökull: evaluating the surface energy budget in a regional climate model with automatic weather station observations
title_full The importance of accurate glacier albedo for estimates of surface mass balance on Vatnajökull: evaluating the surface energy budget in a regional climate model with automatic weather station observations
title_fullStr The importance of accurate glacier albedo for estimates of surface mass balance on Vatnajökull: evaluating the surface energy budget in a regional climate model with automatic weather station observations
title_full_unstemmed The importance of accurate glacier albedo for estimates of surface mass balance on Vatnajökull: evaluating the surface energy budget in a regional climate model with automatic weather station observations
title_sort importance of accurate glacier albedo for estimates of surface mass balance on vatnajökull: evaluating the surface energy budget in a regional climate model with automatic weather station observations
publisher Copernicus Publications
publishDate 2017
url https://doi.org/10.5194/tc-11-1665-2017
https://noa.gwlb.de/receive/cop_mods_00009599
https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00009556/tc-11-1665-2017.pdf
https://tc.copernicus.org/articles/11/1665/2017/tc-11-1665-2017.pdf
long_lat ENVELOPE(-16.823,-16.823,64.420,64.420)
geographic Vatnajökull
geographic_facet Vatnajökull
genre glacier
Ice cap
Iceland
The Cryosphere
Vatnajökull
genre_facet glacier
Ice cap
Iceland
The Cryosphere
Vatnajökull
op_relation The Cryosphere -- ˜Theœ Cryosphere -- http://www.bibliothek.uni-regensburg.de/ezeit/?2393169 -- http://www.the-cryosphere.net/ -- 1994-0424
https://doi.org/10.5194/tc-11-1665-2017
https://noa.gwlb.de/receive/cop_mods_00009599
https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00009556/tc-11-1665-2017.pdf
https://tc.copernicus.org/articles/11/1665/2017/tc-11-1665-2017.pdf
op_rights uneingeschränkt
info:eu-repo/semantics/openAccess
op_doi https://doi.org/10.5194/tc-11-1665-2017
container_title The Cryosphere
container_volume 11
container_issue 4
container_start_page 1665
op_container_end_page 1684
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