Possible New Continental Heat Record for Antarctica
On March 24th Base Esperanza (under Argentinean administration) located near the northern tip of the Antarctic Peninsula reported a temperature of 17.5°C (63.5°F). Although this is the warmest temperature ever measured since weather stations became established on the southern continent, it is complicated by what the very definition of ‘Antarctica’ is. Here’s a brief review.
Argentina’s Esperanza Base on the northern tip of the Antarctic Peninsula. It is located near 63°S latitude. Image from Wikipedia.
METAR tables for Base Esperanza (top) and Base Marambio (bottom) for the days of March 23-24. The 17.5°C (63.5°F) at Esperanza on March 24th and 17.4°C (63.3°F) at Marambio on March 23rd exceed any temperatures yet measured on or very close to the Antarctic landmass. Tables from OGIMET.
The 17.5°C (63.5°F) temperature at Esperanza occurred just one day following a reading of 17.4°C (63.3°F) measured at Base Marambio (also under Argentinean administration) on March 23rd. Marambio is located about 60 miles (100 km) southeast of Esperanza. Both figures surpass any temperature yet measured at either site. Esperanza’s previous record high of 17.0°C (62.6°F) was recorded in October 1976 according to weather records researcher Maximiliano Herrera. More importantly, the temperature at Esperanza exceeds any figure yet observed on the Antarctic landmass or Peninsula. According to the WMO, the all-time warmest temperature yet observed in Antarctica was 15.0°C (59.0°F) at Vanda Station on January 5, 1974. Vanda Station is located near 77°S latitude but was occupied for only brief periods, mostly during the Austral summers, between 1967-1995. It now has an automated weather station and is occasionally visited by researchers. Base Esperanza’s weather records began in 1945 according to data published in The World Survey of Climatology: Vol. 14, The Polar Regions. On page p. 353 there is a table of climate data for Esperanza based upon the POR of 1945-1960. I am not sure if the POR has been continuous since 1960 up to the present. Base Marambio was founded in 1969 and is a relatively large facility with at least 55 year-round personnel, a total that swells to 200 during the summer.
Map of Antarctica showing the locations of the various sites referred to in this blog. A table of what the highest observed temperature on record for each of the four sites discussed is below the map.
Despite the fact that the temperature record from Vanda appears on the list of world weather extremes maintained by the WMO, the WMO has not yet investigated all-time weather records for Antarctica, so the Vanda reading and the recent observations at Esperanza and Marambio remain ‘unofficial’ (so far as continental world-record-temperature extremes are concerned).
That being said, and given the recent extraordinary temperatures observed at Esperanza and Marambio, there is a chance that the WMO may wish to launch such (an investigation of Antarctica’s warmest measured temperature).
Should this happen the first issue will be the definition of the region of ‘Antarctica’ for the purpose of weather records relating to the continent. There could be perhaps three (or even four) possible scenarios.
1) The narrowest interpretation might be to include only sites that are south of the Antarctic Circle (near 66°S latitude). In that case, Esperanza would not be part of the record set and the Vanda figure might stand.
2) A more broadly accepted definition would be that adopted by the Antarctic Treaty System in 1961 which defined ‘Antarctica’ to include all land and ice shelves located south of the 60°S latitude. Should this interpretation be used, then the South Orkney Islands, which lie about 500 kilometers northeast of the northern tip of the Antarctic Peninsula, would fall inside the investigation area. That would mean that the British outpost, Signy Research Station (latitude near 60° 43’S), on Signy Island would have measured the warmest temperature on record in Antarctica with a 19.8°C (67.6°F) on January 30, 1982 according to research by Maximiliano Herrera.
3) The third possible definition would be to include only the landmass of Antarctica (although the Antarctica Peninsula is actually composed of a series of islands connected to one another by ice sheets). In that case the recent 17.5°C at Base Esperanza would most likely stand as the warmest temperature yet measured on the continent.
4) Maximiliano adds yet a possible fourth consideration: areas associated with the Antarctic geological shelf. See his note on his Wiki page of continental records here. He adds the following footnote: “If we consider the geological case, Amsterdam Island, (located at 37° 49'S and 77° 33'E), which belongs to the French dependence of the French Southern and Antarctic Lands and associated with Africa, lies on the Antarctic plate and has a highest temperature of 26.4°C (79.4°F) on 30 January 2005”.
More About the Unusual Warmth at Bases Esperanza and Marambio
One surprising aspect of the temperatures measured recently at Esperanza and Marambio are that they occurred in autumn, nearly three months past the usual warmest time of the year in the Antarctic Peninsula. According to NOAA December is typically the warmest month in Esperanza, with an average high temperature of 37.8°F (3.2°C). The March average high temperature is 31.3°F (-0.4°C), so temperatures on Tuesday, March 25th, were more than 30°F (17°C) above average. However, looking at the statistics in the World Survey of Climatology (referred to earlier) it is interesting to note that the warmest temperature observed at Esperanza during the period of 1945-1960 was a 14.6°C reading during an October and the 2nd warmest was 14.2°C during an April (also tied in January). So we can see that record high temperatures for Esperanza are not confined to just the summer months.
Departure of temperature from average for Tuesday, March, 24, 2015, over Antarctica. Temperatures were more than 30°F (17°C) above average. Image credit: University of Main Climate Reanalyzer.
A strong high pressure ridge and a Foehn wind led to the record temperatures as Jeff Masters explains here:
This week's record temperatures were made possible by an unusually extreme jet stream contortion that brought a strong ridge of high pressure over the Antarctic Peninsula, allowing warm air from South America to push southwards over Antarctica. At the surface, west to east blowing winds over the Antarctic Peninsula rose up over the 1,000-foot high mountains just to the west of Esperanza Base, then descended and warmed via adiabatic compression into a warm foehn wind that reached 44 mph (71 km/hr) at 09 UTC on March 24th, near when the maximum temperature was recorded. A similar event also affected Marambio on the 23rd.
Jet stream image for Tuesday, March, 24, 2015, over Antarctica. An unusually extreme contortion of the jet stream allowed a ridge of high pressure to extend far to the south over the Antarctic Peninsula, bringing record-warm air from South America. Image credit: : University of Main Climate Reanalyzer.
KUDOS: Thanks to Maximiliano Herrera for bringing this to our attention and researching the temperature records for Antarctica.
Christopher C. Burt
Weather Historian
On March 24th Base Esperanza (under Argentinean administration) located near the northern tip of the Antarctic Peninsula reported a temperature of 17.5°C (63.5°F). Although this is the warmest temperature ever measured since weather stations became established on the southern continent, it is complicated by what the very definition of ‘Antarctica’ is. Here’s a brief review.
Argentina’s Esperanza Base on the northern tip of the Antarctic Peninsula. It is located near 63°S latitude. Image from Wikipedia.
METAR tables for Base Esperanza (top) and Base Marambio (bottom) for the days of March 23-24. The 17.5°C (63.5°F) at Esperanza on March 24th and 17.4°C (63.3°F) at Marambio on March 23rd exceed any temperatures yet measured on or very close to the Antarctic landmass. Tables from OGIMET.
The 17.5°C (63.5°F) temperature at Esperanza occurred just one day following a reading of 17.4°C (63.3°F) measured at Base Marambio (also under Argentinean administration) on March 23rd. Marambio is located about 60 miles (100 km) southeast of Esperanza. Both figures surpass any temperature yet measured at either site. Esperanza’s previous record high of 17.0°C (62.6°F) was recorded in October 1976 according to weather records researcher Maximiliano Herrera. More importantly, the temperature at Esperanza exceeds any figure yet observed on the Antarctic landmass or Peninsula. According to the WMO, the all-time warmest temperature yet observed in Antarctica was 15.0°C (59.0°F) at Vanda Station on January 5, 1974. Vanda Station is located near 77°S latitude but was occupied for only brief periods, mostly during the Austral summers, between 1967-1995. It now has an automated weather station and is occasionally visited by researchers. Base Esperanza’s weather records began in 1945 according to data published in The World Survey of Climatology: Vol. 14, The Polar Regions. On page p. 353 there is a table of climate data for Esperanza based upon the POR of 1945-1960. I am not sure if the POR has been continuous since 1960 up to the present. Base Marambio was founded in 1969 and is a relatively large facility with at least 55 year-round personnel, a total that swells to 200 during the summer.
Map of Antarctica showing the locations of the various sites referred to in this blog. A table of what the highest observed temperature on record for each of the four sites discussed is below the map.
Despite the fact that the temperature record from Vanda appears on the list of world weather extremes maintained by the WMO, the WMO has not yet investigated all-time weather records for Antarctica, so the Vanda reading and the recent observations at Esperanza and Marambio remain ‘unofficial’ (so far as continental world-record-temperature extremes are concerned).
That being said, and given the recent extraordinary temperatures observed at Esperanza and Marambio, there is a chance that the WMO may wish to launch such (an investigation of Antarctica’s warmest measured temperature).
Should this happen the first issue will be the definition of the region of ‘Antarctica’ for the purpose of weather records relating to the continent. There could be perhaps three (or even four) possible scenarios.
1) The narrowest interpretation might be to include only sites that are south of the Antarctic Circle (near 66°S latitude). In that case, Esperanza would not be part of the record set and the Vanda figure might stand.
2) A more broadly accepted definition would be that adopted by the Antarctic Treaty System in 1961 which defined ‘Antarctica’ to include all land and ice shelves located south of the 60°S latitude. Should this interpretation be used, then the South Orkney Islands, which lie about 500 kilometers northeast of the northern tip of the Antarctic Peninsula, would fall inside the investigation area. That would mean that the British outpost, Signy Research Station (latitude near 60° 43’S), on Signy Island would have measured the warmest temperature on record in Antarctica with a 19.8°C (67.6°F) on January 30, 1982 according to research by Maximiliano Herrera.
3) The third possible definition would be to include only the landmass of Antarctica (although the Antarctica Peninsula is actually composed of a series of islands connected to one another by ice sheets). In that case the recent 17.5°C at Base Esperanza would most likely stand as the warmest temperature yet measured on the continent.
4) Maximiliano adds yet a possible fourth consideration: areas associated with the Antarctic geological shelf. See his note on his Wiki page of continental records here. He adds the following footnote: “If we consider the geological case, Amsterdam Island, (located at 37° 49'S and 77° 33'E), which belongs to the French dependence of the French Southern and Antarctic Lands and associated with Africa, lies on the Antarctic plate and has a highest temperature of 26.4°C (79.4°F) on 30 January 2005”.
More About the Unusual Warmth at Bases Esperanza and Marambio
One surprising aspect of the temperatures measured recently at Esperanza and Marambio are that they occurred in autumn, nearly three months past the usual warmest time of the year in the Antarctic Peninsula. According to NOAA December is typically the warmest month in Esperanza, with an average high temperature of 37.8°F (3.2°C). The March average high temperature is 31.3°F (-0.4°C), so temperatures on Tuesday, March 25th, were more than 30°F (17°C) above average. However, looking at the statistics in the World Survey of Climatology (referred to earlier) it is interesting to note that the warmest temperature observed at Esperanza during the period of 1945-1960 was a 14.6°C reading during an October and the 2nd warmest was 14.2°C during an April (also tied in January). So we can see that record high temperatures for Esperanza are not confined to just the summer months.
Departure of temperature from average for Tuesday, March, 24, 2015, over Antarctica. Temperatures were more than 30°F (17°C) above average. Image credit: University of Main Climate Reanalyzer.
A strong high pressure ridge and a Foehn wind led to the record temperatures as Jeff Masters explains here:
This week's record temperatures were made possible by an unusually extreme jet stream contortion that brought a strong ridge of high pressure over the Antarctic Peninsula, allowing warm air from South America to push southwards over Antarctica. At the surface, west to east blowing winds over the Antarctic Peninsula rose up over the 1,000-foot high mountains just to the west of Esperanza Base, then descended and warmed via adiabatic compression into a warm foehn wind that reached 44 mph (71 km/hr) at 09 UTC on March 24th, near when the maximum temperature was recorded. A similar event also affected Marambio on the 23rd.
Jet stream image for Tuesday, March, 24, 2015, over Antarctica. An unusually extreme contortion of the jet stream allowed a ridge of high pressure to extend far to the south over the Antarctic Peninsula, bringing record-warm air from South America. Image credit: : University of Main Climate Reanalyzer.
KUDOS: Thanks to Maximiliano Herrera for bringing this to our attention and researching the temperature records for Antarctica.
Christopher C. Burt
Weather Historian
6. panamint
2:29 AM GMT on March 27, 2015|
It is just convention that we separate the world into continents
(generally being the continental land masses, although Europe is split
off from Eurasia for whatever reason), but there are only seven of them.
Any remaining islands are then placed into one of these continents for
grouping, statistical, political and other purposes, but it's an ad hoc
thing done for various reasons. The South Orkneys are very roughly 400 miles from the Antarctic mainland, but maybe 1200 miles from South America, so common sense says they're grouped as part of Antarctica. When discussing continental temperature records, I am quite comfortable with Signy Island taking the Antarctic record with a footnote that Base Esperanza has the Antarctic mainland record. PS Good to have you back Chris! |
5. BaltimoreBrian
1:26 AM GMT on March 27, 2015| I don't have a big problem with including the South Shetland islands in Antarctica, although I'd also like to see a separate record for the 'mainland' of Antarctica in that case. The South Orkney Islands don't have to be included with a continent but could be just their own group. |
4. panamint
1:10 AM GMT on March 27, 2015|
Any good look at an atlas will illustrate that Signy Island and the
rest of the South Orkney Islands are an extension north-eastwards of the
spine of the Antarctic Peninsula, so geologically they are a part of
Antarctica (and also politically through the Antarctic Treaty as they
lie south of 60S). Any land northwards of 60S obviously fails the
political test. If the South Orkneys are to be excluded from Antarctica, then logically they must be included in South America, so now we have a new reliable absolute minimum temperature for South America of -40.1C, which also comes from Signy Island. Lots of luck in getting that record past the "bunch of inepts" (Max's description) at WMO. |
3. BaltimoreBrian
11:55 PM GMT on March 26, 2015
My opinion is that Antarctica consists of the continent and
immediately adjacent islands. Esperanza and Marimbio are part of
Antarctica and the South Orkney Islands are not. I'd include the Palmer
Islands in Antarctica and not the South Shetland Islands. Yes, I'm being
arbitrary :) Click on map below to expand.
|
2. FormosanBlackBear
2:06 PM GMT on March 26, 2015| God to have you back! Hope you enjoy the vacation! |
1. maxcrc
10:27 AM GMT on March 26, 2015|
Inded, Esperanza and Marambio records are OFFICIAL and confirmed , not unofficial. Several other stations have recorded OFFICIAL temperatures above 15C: Larsen 16.1C Base Orcadas 15.2C Base San Martin 15.0C few stations in the King George island with official records as high as 16.7C. Not to mention the previous OFFICIAL records of Esperanza (17.0C) and Marambio (16.5C). It is not up to the WMO, whose workers are a bunch of inepts without even the minimal knowledge of the very basic of climatology to decide what is official or not In fact, almost all their Continental records are completely wrong, they are so ridiculous and physically impossible that even a kindergarten 3 years old kid would laugh like crazy at those absurde data. So it's s completely IRRELEVANT what those lazy bureaucrats do or don't do. Why don't you tell to the New Zealand MetService that their OFFICIAL and 100% correct national record of 42.4C set in 1973 is unofficial because the WMO prefers a completely wrong record 42.2C set in 1912 in the Philippines without a Stevenson Screen as the Oceania highest temperature ? A wrong temperature, a lower temperature in any case in another continent. Fantastic ! They would probably suggest you a good shrink or to go back to the primary school and study some geography and science. These readings above are also 100% OFFICIAL according to the National Institutes of Meteorology and Institutions which manage them. There is no way we can spit on their work only to favor an extremely corrupt and incompetent institution. The issue whether to include the South Orkney Islands in Antarctica is the only debatable point here. |
7. BaltimoreBrian
2:54 AM GMT on March 27, 2015