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Long-term variability in precipitation and streamfiow in Iceland and relations to atmospheric circulation

Jonsdottir, Jona Finndis LU and Bertacchi Uvo, Cintia LU (2009) In International Journal of Climatology 29(10). p.1369-1380
Abstract
How the variability of the atmospheric circulation affects precipitation in Iceland is not completely understood. Also, the sea surface temperature (SST) has a strong influence on the temperature over the country, and thereby, snow and glacial melt. This study, therefore, aims at explaining how atmospheric circulation and sea surface temperature influence seasonal and annual precipitation, and, consequently, runoff in Iceland. Empirical orthogonal function (EOF) analysis is performed on annual and seasonal time series of precipitation and discharge to identify their key modes of variability during the period 1966-2004. The correlation between the time series of each EOF mode with individual time series of sea level pressure (SLP), air... (More)
How the variability of the atmospheric circulation affects precipitation in Iceland is not completely understood. Also, the sea surface temperature (SST) has a strong influence on the temperature over the country, and thereby, snow and glacial melt. This study, therefore, aims at explaining how atmospheric circulation and sea surface temperature influence seasonal and annual precipitation, and, consequently, runoff in Iceland. Empirical orthogonal function (EOF) analysis is performed on annual and seasonal time series of precipitation and discharge to identify their key modes of variability during the period 1966-2004. The correlation between the time series of each EOF mode with individual time series of sea level pressure (SLP), air temperature and SST was then evaluated. The analyses evidenced how large-scale climate variables are connected to the regional precipitation and runoff in Iceland. They showed that the strength of the polar vortex may be, at least, as important for the precipitation in some areas of Iceland as the strength of the Icelandic Low (IL). Moreover, the location of the semi-permanent IL often defines the predominant wind direction over the country and, as such, the regions of preferred precipitation. Since the watersheds act as large precipitation gauges with response patterns depending on the geology and glaciers, the variability of the annual discharge closely resembles the variability of precipitation, except for the glacial rivers. Glacial melt is highly correlated to air temperature and SST, and the spring discharge is affected by winter and spring temperatures. The results also revealed that Icelandic hydrological conditions in the spring can be forecasted by precipitation and temperature of the autumn and winter seasons, as well as by the general prevalent circulation patterns. Additionally, a potential for seasonal forecast of precipitation, and river discharge in other seasons was identified, particularly if seasonal forecast of SLP is available. Copyright (C) 2008 Royal Meteorological Society (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
empirical orthogonal function, hydrology, atmospheric circulation, variability, Iceland, North Atlantic
in
International Journal of Climatology
volume
29
issue
10
pages
1369 - 1380
publisher
John Wiley & Sons
external identifiers
  • wos:000269401000003
  • scopus:69949106228
ISSN
1097-0088
DOI
10.1002/joc.1781
language
English
LU publication?
yes
id
26249d46-ec83-452c-b581-5f1cbd319787 (old id 1476291)
date added to LUP
2009-09-29 11:58:22
date last changed
2017-05-21 03:43:01
@article{26249d46-ec83-452c-b581-5f1cbd319787,
  abstract     = {How the variability of the atmospheric circulation affects precipitation in Iceland is not completely understood. Also, the sea surface temperature (SST) has a strong influence on the temperature over the country, and thereby, snow and glacial melt. This study, therefore, aims at explaining how atmospheric circulation and sea surface temperature influence seasonal and annual precipitation, and, consequently, runoff in Iceland. Empirical orthogonal function (EOF) analysis is performed on annual and seasonal time series of precipitation and discharge to identify their key modes of variability during the period 1966-2004. The correlation between the time series of each EOF mode with individual time series of sea level pressure (SLP), air temperature and SST was then evaluated. The analyses evidenced how large-scale climate variables are connected to the regional precipitation and runoff in Iceland. They showed that the strength of the polar vortex may be, at least, as important for the precipitation in some areas of Iceland as the strength of the Icelandic Low (IL). Moreover, the location of the semi-permanent IL often defines the predominant wind direction over the country and, as such, the regions of preferred precipitation. Since the watersheds act as large precipitation gauges with response patterns depending on the geology and glaciers, the variability of the annual discharge closely resembles the variability of precipitation, except for the glacial rivers. Glacial melt is highly correlated to air temperature and SST, and the spring discharge is affected by winter and spring temperatures. The results also revealed that Icelandic hydrological conditions in the spring can be forecasted by precipitation and temperature of the autumn and winter seasons, as well as by the general prevalent circulation patterns. Additionally, a potential for seasonal forecast of precipitation, and river discharge in other seasons was identified, particularly if seasonal forecast of SLP is available. Copyright (C) 2008 Royal Meteorological Society},
  author       = {Jonsdottir, Jona Finndis and Bertacchi Uvo, Cintia},
  issn         = {1097-0088},
  keyword      = {empirical orthogonal function,hydrology,atmospheric circulation,variability,Iceland,North Atlantic},
  language     = {eng},
  number       = {10},
  pages        = {1369--1380},
  publisher    = {John Wiley & Sons},
  series       = {International Journal of Climatology},
  title        = {Long-term variability in precipitation and streamfiow in Iceland and relations to atmospheric circulation},
  url          = {http://dx.doi.org/10.1002/joc.1781},
  volume       = {29},
  year         = {2009},
}