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Numerical simulations of precipitation in the complex terrain of Iceland - Comparison with glaciological and hydrological data

Roegnvaldsson, Olafur; Jonsdottir, Jona Finndis LU and Olafsson, Haraldur (2007) In Meteorologische Zeitschrift 16(1). p.71-85
Abstract
Atmospheric flow over Iceland has been simulated for the period September 1987 through June 2003, using the PSU/NCAR MM5 mesoscale model driven by initial and boundary data from the European Centre for Medium-range Weather Forecasts (ECMWF). The simulated precipitation is compared with two types of indirect precipitation observations. Firstly, snow accumulation on two large ice caps in SE-Iceland and on two large glaciers in central Iceland. Secondly, model output is used as input to the WaSiM-ETH hydrological model to calculate and compare the runoff with observed runoff from six watersheds in Iceland for the water years 1987-2002. Model precipitation compares favourably with both types of validation data. The seasonal and inter-annual... (More)
Atmospheric flow over Iceland has been simulated for the period September 1987 through June 2003, using the PSU/NCAR MM5 mesoscale model driven by initial and boundary data from the European Centre for Medium-range Weather Forecasts (ECMWF). The simulated precipitation is compared with two types of indirect precipitation observations. Firstly, snow accumulation on two large ice caps in SE-Iceland and on two large glaciers in central Iceland. Secondly, model output is used as input to the WaSiM-ETH hydrological model to calculate and compare the runoff with observed runoff from six watersheds in Iceland for the water years 1987-2002. Model precipitation compares favourably with both types of validation data. The seasonal and inter-annual variability of precipitation is investigated at low as well as high altitudes. The simulations reveal a negative trend in the winter precipitation in W-Iceland, but a positive trend in the ratio of lowland precipitation to mountain precipitation in E-Iceland. There is in general a substantial inter-annual variability in the ratio of lowland precipitation to precipitation in the mountains, especially in E-Iceland, emphasizing the limitation of precipitation observations in the lowlands as a proxy for precipitation in the mountains. In order to assess the impact of orography on the precipitation climate of Iceland, precipitation is simulated with flat Iceland and compared to a simulation with true orography. It is found that the mountains contribute to a total increase of precipitation in Iceland of the order of 40 %. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Meteorologische Zeitschrift
volume
16
issue
1
pages
71 - 85
publisher
E Schweizerbartsche Verlags
external identifiers
  • wos:000248132600009
  • scopus:33947373031
ISSN
1610-1227
DOI
10.1127/0941-2948/2007/0174
language
English
LU publication?
yes
id
5b947164-3f75-4f3d-989f-dda5027db1ac (old id 691556)
date added to LUP
2007-12-18 11:26:58
date last changed
2017-01-01 05:09:06
@article{5b947164-3f75-4f3d-989f-dda5027db1ac,
  abstract     = {Atmospheric flow over Iceland has been simulated for the period September 1987 through June 2003, using the PSU/NCAR MM5 mesoscale model driven by initial and boundary data from the European Centre for Medium-range Weather Forecasts (ECMWF). The simulated precipitation is compared with two types of indirect precipitation observations. Firstly, snow accumulation on two large ice caps in SE-Iceland and on two large glaciers in central Iceland. Secondly, model output is used as input to the WaSiM-ETH hydrological model to calculate and compare the runoff with observed runoff from six watersheds in Iceland for the water years 1987-2002. Model precipitation compares favourably with both types of validation data. The seasonal and inter-annual variability of precipitation is investigated at low as well as high altitudes. The simulations reveal a negative trend in the winter precipitation in W-Iceland, but a positive trend in the ratio of lowland precipitation to mountain precipitation in E-Iceland. There is in general a substantial inter-annual variability in the ratio of lowland precipitation to precipitation in the mountains, especially in E-Iceland, emphasizing the limitation of precipitation observations in the lowlands as a proxy for precipitation in the mountains. In order to assess the impact of orography on the precipitation climate of Iceland, precipitation is simulated with flat Iceland and compared to a simulation with true orography. It is found that the mountains contribute to a total increase of precipitation in Iceland of the order of 40 %.},
  author       = {Roegnvaldsson, Olafur and Jonsdottir, Jona Finndis and Olafsson, Haraldur},
  issn         = {1610-1227},
  language     = {eng},
  number       = {1},
  pages        = {71--85},
  publisher    = {E Schweizerbartsche Verlags},
  series       = {Meteorologische Zeitschrift},
  title        = {Numerical simulations of precipitation in the complex terrain of Iceland - Comparison with glaciological and hydrological data},
  url          = {http://dx.doi.org/10.1127/0941-2948/2007/0174},
  volume       = {16},
  year         = {2007},
}