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Cold Surges (cold + surge)

Distribution by Scientific Domains
Earth and Environmental Science100%

Selected Abstracts

Long-term trends of winter monsoon synoptic circulations over the maritime continent: 1962,2007,

ATMOSPHERIC SCIENCE LETTERS, Issue 3 2010
Liew Juneng
Abstract The present study examines the long-term trends of the winter monsoon northeasterly cold surge and Borneo vortex over the South China Sea. There has been a significant increase in the frequency of the Borneo vortex within the study period of 1962,2007. The location of the center of the Borneo vortices has shifted slightly offshore; northward of western Borneo. This could result in less vortex,land interaction and lengthen the life span of the vortices due to less frictional shear and hence increase the vortex days. These changes could be related to the strengthened easterly component of the cold surge winds. Copyright © 2010 Royal Meteorological Society [source]

Characteristics of wintertime daily and extreme minimum temperature over South Korea

INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 2 2004
Sang-Boom Ryoo
Abstract In South Korea, consecutive positive temperature anomalies have been observed since the mid-1980s. The objective of this study is to assess the recent trends in, and variability of, daily minimum temperature over South Korea with particular emphasis on its extremes. Temporal characteristics of wintertime daily and extreme minimum temperature-related variables were analysed on a seasonal basis for the period of 1958,59 to 2000,01. The results show continually fewer days with extreme low minimum temperature since the mid-1980s. However, no significant change in the 1 day temperature difference was observed during the same period, indicating little change in the frequency of cold surges. Also, during the period analysed, there is a significant positive trend in the seasonal mean temperature, a negative trend in the frequency of the extreme cold days, and no significant trend in the seasonal occurrence of cold surges. Northern Hemisphere geopotential height fields before and after 1986,87, i.e. the start of successive positive anomalies in the winter surface air temperature over South Korea, showed a substantial decrease throughout the troposphere over the polar region. In the upper levels the overall pattern becomes more wavelike, with eddies embedded between meanders. The differences in the lower troposphere are remarkably similar to the Arctic oscillation, although the centre in the North Atlantic is shifted toward western Europe and differences in the North Pacific are relatively weaker than those in the polar region. The recent positive phase of the Arctic oscillation may contribute to these abrupt changes in wintertime daily minimum temperatures over South Korea. El Niño,southern oscillation phenomena appear to contribute to the interannual variation of cold surge days in South Korea. Years with no cold surges were experienced during La Niña episodes. On the other hand, all years with more than four cases of cold surges were during El Niño episodes. Copyright © 2004 Royal Meteorological Society [source]

Subtropical cold surges: regional aspects and global distribution

INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 10 2001
René D. Garreaud
Abstract Shallow surges of cold dry air are frequently observed to the east of the major mountain ranges, moving from mid-latitudes well into the Tropics in about 4 days. Because of their strong impact on weather, regional aspects of cold surges have received considerable attention, particularly over Southeast Asia, to the east of the Rockies and Mexican Sierras, and to the east of the subtropical Andes. Both observational and numerical studies reveal a similar structure and evolution of cold surges in different regions. These common aspects are reviewed in this work, as well as the mechanisms responsible for the development and subsequent advance of cold surges over the subtropics. Atmospheric reanalysis data are used to document the global distribution of cold surges on the basis of their continental-scale imprints on relevant fields, as well as to estimate their contribution on the regional and global energy balances. It is found that cold surges have a major cooling and drying effect over the regions where they are prevalent (e.g. subtropical South America) and represent a sizeable sink of energy for the Tropics. Copyright © 2001 Royal Meteorological Society [source]