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The Siberian High in a Supposedly Warming World
Reference
Jeong, J.-H., Ou, T., Linderholm, H.W., Kim, B.-M., Kim, S.-J., Kug, J.-S. and Chen, D. 2011. Recent recovery of the Siberian High intensity. Journal of Geophysical Research 116: 10.1029/2011JD015904.

Background
In the words of the authors, "the Siberian High (SH) is the most conspicuous pressure system found in the Northern Hemisphere during wintertime," when they indicate that "strong radiative cooling over the snow covered Eurasian continent forms a cold-core high-pressure system in the lower troposphere over northern Mongolia" that exerts "tremendous influences on weather and climate in Northern Eurasia, East Asia, and even further into South Asia (e.g., Cohen et al., 2001; Panagiotopoulos et al., 2005; Wang, 2006)." And of this phenomenon, they state that SH intensity variations - as simulated by 22 global climate models (GCMs) under 20C3M and A1B scenarios in the CMIP3 - show "a steady decreasing trend in the SH intensity from the late 20th century throughout the 21st century, leading to a decrease of about 22% in SH intensity at the end of the 21st century compared to the 1958-1980 average."

What was done
In a study designed to determine to what degree the temporal SH intensity simulations of these models mimic reality, Jeong et al. employed two observational gridded sea level pressure (SLP) data sets - that of the Hadley Centre and that of the National Centre for Atmospheric Research - plus two reanalysis data sets (NCEP and ERA40) and in situ SLP observations from 20 stations located in the central SH region to create a history of SH intensity over the past several decades.

What was learned
The climatic reconstructive work of the seven scientists revealed "a pronounced declining trend of the SH intensity from the late 1960s to the early 1990s," which would appear to mesh well with GCM simulations presented in the IPCC AR4 that indicate a "steady weakening of the SH intensity for the entire 21st century." However, they report that in the real world, the declining SH intensity trend "was sharply replaced by a fast recovery over the last two decades." And they thus make a strong point of noting that "this feature has not been successfully captured by the GCM simulations used for the IPCC AR4," all of which predict "a steady decreasing trend in the SH intensity from the late 20th century throughout the 21st century."

What it means
Quoting the brief final sentence of Jeong et al. in their enlightening paper's abstract - which is a grandiose understatement in our view - "an improvement in predicting the future climate change in regional scale is desirable."

References
Cohen, J., Saito, K. and Entekhabi, D. 2001. The role of the Siberian High in Northern Hemisphere climate variability. Geophysical Research Letters 28: 299-302.

Panagiotopoulos, F., Shahgedanova, M., Hannachi, A. and Stephenson, D.B. 2005. Observed trends and teleconnections of the Siberian High: A recently declining center of action. Journal of Climate 18: 1411-1422.

Wang, B. 2006. The Asian Monsoon. Springer, Berlin, Germany.

Reviewed 11 April 2012