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Reconstruction of a regional drought index in southern Sweden since AD 1750

Drobyshev, Igor; Niklasson, Mats; Linderholm, Hans W.; Seftigen, Kristina; Hickler, Thomas LU and Eggertsson, Olafur (2011) In The Holocene 21(4). p.667-679
Abstract
We used a network of eight pedunculate oak (Quercus robur L.) sites (n(trees) = 70) and one Scots pine (Pinus sylvestris L.) site (n(trees) = 53) to develop drought-sensitive master chronologies for the two areas in southern Scandinavia: a SW-area centred on 57AN 12.7AE and a NE-area centred on 58.8AN 18.2AE. The ratio of actual to equilibrium evapotranspiration (AET/EET) was used as a measure of drought during the growing season defined as the period with average daily temperatures above 9 degrees C. Instrumental data were used to parameterize the relationship between tree-ring data and the drought index (DI) over 1922-2000 for the SW area and over 1922-1995 for the NE area. The DI reconstructions explained 29.7% (SW area) and 43.7% (NE... (More)
We used a network of eight pedunculate oak (Quercus robur L.) sites (n(trees) = 70) and one Scots pine (Pinus sylvestris L.) site (n(trees) = 53) to develop drought-sensitive master chronologies for the two areas in southern Scandinavia: a SW-area centred on 57AN 12.7AE and a NE-area centred on 58.8AN 18.2AE. The ratio of actual to equilibrium evapotranspiration (AET/EET) was used as a measure of drought during the growing season defined as the period with average daily temperatures above 9 degrees C. Instrumental data were used to parameterize the relationship between tree-ring data and the drought index (DI) over 1922-2000 for the SW area and over 1922-1995 for the NE area. The DI reconstructions explained 29.7% (SW area) and 43.7% (NE area) of the variance in the observed DI index in the calibration period, and were extended back to AD 1770 for the SW area and to AD 1750 for the NE area. Reconstructed drought dynamics suggested strong decadal- and century-scale temporal variability and limited regional synchronicity over 1770-2000. Large variations in DI were observed in both regions in the second half of the 1700s. Dry conditions were synchronously reconstructed in both sub-regions during 1781-1784, 1853-1855, and, to a lesser degree, during 1974-1978. Over the 1945-1975 period the SW area exhibited a trend towards drier growing seasons, whereas no such trend could be identified for the NE area. Analysis of correlation maps indicated that regional DI dynamics reflected two different climate regimes, associated with the Kattegat area (SW reconstruction) and southeastern Swedish coast of the Baltic sea (NE reconstruction). (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
climate variation, dendroclimatic reconstruction, drought, oak, precipitation dynamics, Scandinavia, tree rings, water stress
in
The Holocene
volume
21
issue
4
pages
667 - 679
publisher
SAGE Publications Inc.
external identifiers
  • wos:000290946800012
  • scopus:79957638352
ISSN
0959-6836
DOI
10.1177/0959683610391312
project
MERGE
BECC
language
English
LU publication?
yes
id
77609297-a2cf-4964-af4c-4499d557eb4b (old id 1985975)
date added to LUP
2011-07-05 09:48:57
date last changed
2017-09-24 03:18:04
@article{77609297-a2cf-4964-af4c-4499d557eb4b,
  abstract     = {We used a network of eight pedunculate oak (Quercus robur L.) sites (n(trees) = 70) and one Scots pine (Pinus sylvestris L.) site (n(trees) = 53) to develop drought-sensitive master chronologies for the two areas in southern Scandinavia: a SW-area centred on 57AN 12.7AE and a NE-area centred on 58.8AN 18.2AE. The ratio of actual to equilibrium evapotranspiration (AET/EET) was used as a measure of drought during the growing season defined as the period with average daily temperatures above 9 degrees C. Instrumental data were used to parameterize the relationship between tree-ring data and the drought index (DI) over 1922-2000 for the SW area and over 1922-1995 for the NE area. The DI reconstructions explained 29.7% (SW area) and 43.7% (NE area) of the variance in the observed DI index in the calibration period, and were extended back to AD 1770 for the SW area and to AD 1750 for the NE area. Reconstructed drought dynamics suggested strong decadal- and century-scale temporal variability and limited regional synchronicity over 1770-2000. Large variations in DI were observed in both regions in the second half of the 1700s. Dry conditions were synchronously reconstructed in both sub-regions during 1781-1784, 1853-1855, and, to a lesser degree, during 1974-1978. Over the 1945-1975 period the SW area exhibited a trend towards drier growing seasons, whereas no such trend could be identified for the NE area. Analysis of correlation maps indicated that regional DI dynamics reflected two different climate regimes, associated with the Kattegat area (SW reconstruction) and southeastern Swedish coast of the Baltic sea (NE reconstruction).},
  author       = {Drobyshev, Igor and Niklasson, Mats and Linderholm, Hans W. and Seftigen, Kristina and Hickler, Thomas and Eggertsson, Olafur},
  issn         = {0959-6836},
  keyword      = {climate variation,dendroclimatic reconstruction,drought,oak,precipitation dynamics,Scandinavia,tree rings,water stress},
  language     = {eng},
  number       = {4},
  pages        = {667--679},
  publisher    = {SAGE Publications Inc.},
  series       = {The Holocene},
  title        = {Reconstruction of a regional drought index in southern Sweden since AD 1750},
  url          = {http://dx.doi.org/10.1177/0959683610391312},
  volume       = {21},
  year         = {2011},
}