Sudden stratospheric warming
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A sudden stratospheric warming (SSW) is an event in which polar stratospheric temperatures rise by several tens of kelvins (up to increases of about 50 °C (90 °F)) over the course of a few days.[1] The warming is preceded by a slowing then reversal of the westerly winds in the stratospheric polar vortex. SSWs occur about six times per decade in the northern hemisphere,[2] and about once every 20-30 years in the southern hemisphere.[3][4] Only two southern SSWs have been observed.[5]
History
The first continued measurements of the stratosphere were taken by
In 1979 when the satellite era began, meteorological measurements became far more frequent. Although satellites were primarily used for the troposphere they also recorded data for the stratosphere. Today both satellites and stratospheric radiosondes are used to take measurements of the stratosphere.
Classification and description
SSW is closely associated with
Sometimes a fourth category, the Canadian warming, is included because of its unique and distinguishing structure and evolution.
"There are two main types of SSW: displacement events in which the stratospheric polar vortex is displaced from the pole and split events in which the vortex splits into two or more vortices. Some SSWs are a combination of both types".[2]
Major
These occur when the westerly winds at 60N and 10 hPa reverse, i.e. become easterly. A complete disruption of the polar vortex is observed and the vortex will either be split into daughter vortices, or displaced from its normal location over the pole.
According to the World Meteorological Organization's Commission for Atmospheric Sciences (Mclnturff, 1978)[who?]: a stratospheric warming can be said to be major if at 10 mb or below the latitudinal mean temperature increases poleward from 60 degree latitude and an associated circulation reversal is observed (that is, the prevailing mean westerly winds poleward of 60 latitude are succeeded by mean easterlies in the same area).
Minor
Minor warmings are similar to major warmings however they are less dramatic, the westerly winds are slowed, however do not reverse. Therefore, a breakdown of the vortex is never observed.
Mclnturff[who?] states: a stratospheric warming is called minor if a significant temperature increase is observed (that is, at least 25 degrees in a period of week or less) at any stratospheric level in any area of winter time hemisphere. The polar vortex is not broken down and the wind reversal from westerly to easterly is less extensive.
Final
The radiative cycle in the stratosphere means that during winter the mean flow is westerly and during summer it is easterly (westward). A final warming occurs on this transition, so that the polar vortex winds change direction for the warming and do not change back until the following winter. This is because the stratosphere has entered the summer easterly phase. It is final because another warming cannot occur over the summer, so it is the final warming of the current winter.
Canadian
Canadian warmings occur in early winter in the stratosphere of the Northern Hemisphere, typically from mid November to early December. They have no counterpart in the southern hemisphere.
Dynamics
In a usual northern-hemisphere winter, several minor warming events occur, with a major event occurring roughly every two years. One reason for major stratospheric warmings to occur in the Northern hemisphere is because
At an initial time a
There exists a link between sudden stratospheric warmings and the
Weather effects
Although sudden stratospheric warmings are mainly forced by planetary scale waves which propagate up from the lower atmosphere, there is also a subsequent return effect of sudden stratospheric warmings on surface weather. Following a sudden stratospheric warming, the high altitude westerly winds reverse and are replaced by easterlies. The easterly winds progress down through the atmosphere, often leading to a weakening of the tropospheric westerly winds, resulting in dramatic reductions in temperature in Northern Europe.[15] This process can take a few days to a few weeks to occur.[1]
Table of Major mid-winter Sudden Stratospheric Warming Events in Reanalyses Products[16]
Event Name | NCEP-NCAR | ERA40 | ERA-Interim
|
JRA-55 | MERRA2 | ENSO | QBO 50mb |
---|---|---|---|---|---|---|---|
JAN 1958 | 30-Jan-58 | 31-Jan-58 | 30-Jan-58 | El Niño | West | ||
NOV 1958 | 30-Nov-58 | **** | **** | El Niño | East | ||
JAN 1960 | 16-Jan-60 | 17-Jan-60 | 17-Jan-60 | Neutral | West | ||
JAN 1963 | **** | 28-Jan-63 | 30-Jan-63 | Neutral | East | ||
MAR 1965 | 23-Mar-65 | **** | **** | La Niña | West | ||
DEC 1965 | 8-Dec-65 | 16-Dec-65 | 18-Dec-65 | El Niño | East | ||
FEB 1966 | 24-Feb-66 | 23-Feb-66 | 23-Feb-66 | El Niño | East | ||
JAN 1968 | **** | 7-Jan-68 | 7-Jan-68 | La Niña | West | ||
NOV 1968 | 27-Nov-68 | 28-Nov-68 | 29-Nov-68 | El Niño | East | ||
MAR 1969 | 13-Mar-69 | 13-Mar-69 | **** | El Niño | East | ||
JAN 1970 | 2-Jan-70 | 2-Jan-70 | 2-Jan-70 | El Niño | West | ||
JAN 1971 | 17-Jan-71 | 18-Jan-71 | 18-Jan-71 | La Niña | East | ||
MAR 1971 | 20-Mar-71 | 20-Mar-71 | 20-Jan-71 | La Niña | East | ||
JAN 1973 | 2-Feb-73 | 31-Jan-73 | 31-Jan-73 | El Niño | East | ||
JAN 1977 | **** | 9-Jan-77 | 9-Jan-77 | El Niño | East | ||
FEB 1979 | 22-Feb-79 | 22-Feb-79 | 22-Feb-79 | 22-Feb-79 | Neutral | West | |
FEB 1980 | 29-Feb-80 | 29-Feb-80 | 29-Feb-80 | 29-Feb-80 | 29-Feb-80 | El Niño | East |
FEB 1981 | **** | **** | **** | 6-Feb-81 | **** | Neutral | West |
MAR 1981 | **** | 4-Mar-81 | 4-Mar-81 | 4-Mar-81 | **** | Neutral | West |
DEC 1981 | 4-Dec-81 | 4-Dec-81 | 4-Dec-81 | 4-Dec-81 | 4-Dec-81 | Neutral | East |
FEB 1984 | 24-Feb-84 | 24-Feb-84 | 24-Feb-84 | 24-Feb-84 | 24-Feb-84 | La Niña | West |
JAN 1985 | 2-Jan-85 | 1-Jan-85 | 1-Jan-85 | 1-Jan-85 | 1-Jan-85 | La Niña | East |
JAN 1987 | 23-Jan-87 | 23-Jan-87 | 23-Jan-87 | 23-Jan-87 | 23-Jan-87 | El Niño | West |
DEC 1987 | 8-Dec-87 | 8-Dec-87 | 8-Dec-87 | 8-Dec-87 | 8-Dec-87 | El Niño | West |
MAR 1988 | 14-Mar-88 | 14-Mar-88 | 14-Mar-88 | 14-Mar-88 | 14-Mar-88 | El Niño | West |
FEB 1989 | 22-Feb-89 | 21-Feb-89 | 21-Feb-89 | 21-Feb-89 | 21-Feb-89 | La Niña | West |
DEC 1998 | 15-Dec-98 | 15-Dec-98 | 15-Dec-98 | 15-Dec-98 | 15-Dec-98 | La Niña | East |
FEB 1999 | 25-Feb-99 | 26-Feb-99 | 26-Feb-99 | 26-Feb-99 | 26-Feb-99 | La Niña | East |
MAR 2000 | 20-Mar-00 | 20-Mar-00 | 20-Mar-00 | 20-Mar-00 | 20-Mar-00 | La Niña | West |
FEB 2001 | 11-Feb-01 | 11-Feb-01 | 11-Feb-01 | 11-Feb-01 | 11-Feb-01 | La Niña | West |
DEC 2001 | 2-Jan-02 | 31-Dec-01 | 30-Dec-01 | 31-Dec-01 | 30-Dec-01 | Neutral | East |
FEB 2002 | **** | 18-Feb-02 | **** | **** | 17-Feb-02 | Neutral | East |
JAN 2003 | 18-Jan-03 | 18-Jan-03 | 18-Jan-03 | 18-Jan-03 | El Niño | West | |
JAN 2004 | 7-Jan-04 | 5-Jan-04 | 5-Jan-04 | 5-Jan-04 | Neutral | East | |
JAN 2006 | 21-Jan-06 | 21-Jan-06 | 21-Jan-06 | 21-Jan-06 | La Niña | East | |
FEB 2007 | 24-Feb-07 | 24-Feb-07 | 24-Feb-07 | 24-Feb-07 | El Niño | West | |
FEB 2008 | 22-Feb-08 | 22-Feb-08 | 22-Feb-08 | 22-Feb-08 | La Niña | East | |
JAN 2009 | 24-Jan-09 | 24-Jan-09 | 24-Jan-09 | 24-Jan-09 | La Niña | West | |
FEB 2010 | 9-Feb-10 | 9-Feb-10 | 9-Feb-10 | 9-Feb-10 | El Niño | West | |
MAR 2010 | 24-Mar-10 | 24-Mar-10 | 24-Mar-10 | 24-Mar-10 | El Niño | West | |
JAN 2013 | 7-Jan-13 | 6-Jan-13 | 7-Jan-13 | 6-Jan-13 | Neutral | East | |
FEB 2018 | 12-Feb-18 | 12-Feb-18 | 12-Feb-18 | 12-Feb-18 | La Niña | West | |
JAN 2019 | 2-Jan-19 | 2-Jan-19 | 2-Jan-19 | 2-Jan-19 | El Niño | East | |
JAN 2021[17][18] | La Niña[19] | West[20] |
See also
References
- ^ a b "Sudden Stratospheric Warming". Met Office.
- ^ .
- ISSN 1748-9326.
- S2CID 236260013.
- PMID 36659119.
- S2CID 53970984.
- ^ Eliassen, A; Palm, T (1960). "On the transfer of energy in stationary mountain waves". Geofysiske Publikasjoner. 22: 1023.
- S2CID 45351011.
- S2CID 119492652.
- PMID 31595070.
- S2CID 122729063.
- S2CID 129826760.
- .
- doi:10.1002/asl.1020.
- hdl:11343/286789.
- ^ Laboratory (CSL), NOAA Chemical Sciences. "NOAA CSL: Chemistry & Climate Processes: SSWC". csl.noaa.gov. Retrieved 2022-11-23.
- ISSN 1748-9326.
- ^ "On the sudden stratospheric warming and polar vortex of early 2021 | NOAA Climate.gov". www.climate.gov. Retrieved 2022-11-23.
- ^ Center, NOAA's Climate Prediction. "NOAA's Climate Prediction Center". origin.cpc.ncep.noaa.gov. Retrieved 2022-11-23.
- ^ "Climate Prediction Center - Monitoring & Data: Current Monthly Atmospheric and Sea Surface Temperatures Index Values". www.cpc.ncep.noaa.gov. Retrieved 2022-11-23.
Further reading
- Butler, Amy H.; Sjoberg, Jeremiah P.; Seidel, Dian J.; Rosenlof, Karen H. (2017). "A sudden stratospheric warming compendium". Earth System Science Data. 9 (1): 63–76. .
- Charlton, Andrew J.; Polvani, Lorenzo M. (2007). "A New Look at Stratospheric Sudden Warmings. Part I: Climatology and Modeling Benchmarks". Journal of Climate. 20 (3): 449. .
- Charlton, Andrew J.; Polvani, Lorenzo M.; Perlwitz, Judith; Sassi, Fabrizio; Manzini, Elisa; Shibata, Kiyotaka; Pawson, Steven; Nielsen, J. Eric; Rind, David (2007). "A New Look at Stratospheric Sudden Warmings. Part II: Evaluation of Numerical Model Simulations". Journal of Climate. 20 (3): 470. .
- Matthewman, N. J.; Esler, J. G.; Charlton-Perez, A. J.; Polvani, L. M. (2009). "A New Look at Stratospheric Sudden Warmings. Part III: Polar Vortex Evolution and Vertical Structure". Journal of Climate. 22 (6): 1566. S2CID 15983602.
- Pedatella, N.; Chau, J.; Schmidt, H.; Goncharenko, L.; Stolle, C.; Hocke, K.; Harvey, L.; Funke, B.; Siddiqui, T. (2018). "How sudden stratospheric warming affects the whole atmosphere". Eos. 99. .
- Hendon, Harry; Watkins, Andrew B.; Lim, Eun-Pa; Young, Griffith (2019-09-06). "The air above Antarctica is suddenly getting warmer – here's what it means for Australia". The Conversation. Retrieved 2019-09-10.