Friday, September 14, 2012

New paper finds Sweden experienced more extreme weather from the 1600's to 1800's than the 20th century

A paper published today in The International Journal of Climatology reconstructs drought conditions in SE Sweden from 1650 to 2002. The authors find that the most extreme drought conditions over the entire 352 year record occurred in the 1660's–1720's, 1800-early 1830's, and in the 1840's–50's. The authors also find the most extreme rainy period took place in the mid-1720's and lasted over 50 years. A graph [below] from the same authors in a prior paper shows a reconstructed drought index in SW and NE Sweden with much more variability of precipitation in the 1700's and 1800's than during the 20th century. Once again, the paleoclimate record proves, contrary to claims of climate alarmists, that there is nothing unprecedented nor remarkable about 20th century extreme weather. 

Reconstructed drought variability in southeastern Sweden since the 1650s

Kristina Seftigen, Hans W. Linderholm, Igor Drobyshev, Mats Niklasson

Abstract: In this study, we present the first regional reconstruction of summer drought for southeastern Sweden. The June–July standardized precipitation index (SPI) was reconstructed over the period 1650–2002 based on Pinus sylvestris L. tree-ring width data, where the reconstruction could account for 41.6% of the total variance in the instrumental record over 1901–2002. Our reconstruction suggests an overall wet 18th century and a dry 19th century. The most outstanding pluvial [rainy] phase in the pre-instrumental period took place in the mid-1720s and lasted over 50 years, while multi-decadal periods of below average moisture conditions were reconstructed in the 1660s–1720s, 1800s-early 30s, and in the 1840s–50s. Several of these dry spells have previously been found in reconstructions from Sweden and Finland, indicating that our reconstruction reflects large-scale moisture anomalies across eastern Fennoscandia. Comparison of the SPI estimates with mid-tropospheric pressure patterns suggests that summertime drought is associated with positive pressure anomalies over British Isles and the North Sea, while an eastward movement of the Icelandic low-pressure systems over the western part of central Fennoscandia results in wetter than normal June–July conditions over the region of interest.

No comments:

Post a Comment