Klimatyczny wskaźnik aktywności Prądu Labradorskiego

• Autorzy: Marsz A. A.

Warianty tytułu

EN

Climatic index of Labrador Current activity

• Języki publikacji: PL

Abstrakty

EN

Some of the sea currents show strong activity in climate formation and this fact is well known. Their activity represented as a time function is not stable but proves to be changeable. For this reason it seems quite reasonable to introduce appropriate indexes which could be used to characte-rise activity of a given current and, in an indirect way, to describe heat masses carried with this current. The aim of this article is to present an index which characterises the climatic activity of the Labrador Current. The basis to create such an index is the number of icebergs carried with this current. In consecutive ice seasons (October - September) this number passed south of 48°N of E from New Foundland (data from ?International Ice Patrol?). Changeable from year to year number of icebergs carried to the North Atlantic (see fig. 2) primarily represents the increase or decrease in the intensity of the Labrador Current. As the number of icebergs moved to the Atlantic comprises random component, which is very high, in order to create the index a logarythm was used to reduce the changeability of the amplitude. Formula [ 1 ] has been proposed to be used to calculate the index of intensity of the Labrador Current (WPL): WPL= (ln(G + 1))/2 where: ln - natural logarythm (base = e), G - the number of icebergs noted in a given ice season. Values of WPL index calculated in this way dated in January in ice season over a period 1900?2002 have been presented in Table 2 and their course in Fig. 3. The value of WPL indicates quite strong correlation with both winter (DJFM) and annual NAO indexes (r ~ 0.5), however the analysis showed that NAO is not the only element having influence on the Labrador Current activity. The analysis, carried out at random, of relations between the values of WPL and different climatic and hydroclimatic elements indicated to the fact that most of the relations are shifted/delayed in time - changeability of WPL takes place earlier than changes in these elements. For instance, the air temperature in August the following year in most area of Poland proves to have not too strong but clear correlation with the changes in WPL. Numerous correlations between WPL and occurring later monthly values of air temperature and monthly sums of precipitation at stations in the Atlantic sector of Arctica have been observed. The size of sea ice cover in the Barents Sea in the following year has shown especially high correlation with the changeability of WPL (the changeability of WPL explains ~50% of changeability in the area of the sea ice cover of the Barents Sea in January the following year). In this way WPL seems to be potentially useful in long term predictors of weather forecasts. The delayed activity of WPL can be explained by means of the following cause- and-effect chain of actions: winter (DJFM) atmpspheric circulation over the Davis Strait and the Labrador Sea has influence on the activity of the Labrador Current - the activity of the Labrador Current has influence on the extent and size of the anomalies in SST in the Labrador Sea and in NW part of the Atlantic (MJJA) - the presence of such anomalies in SST has a modifying effect on the atmospheric circulation occurring in the following autumn (SON) and winter (DJFM).

Słowa kluczowe

PL

prądy morskie; Prąd Labradorski

EN

sea current; Labrador Current

• Wydawca: Stowarzyszenie Klimatologów Polskich
• Czasopismo: Problemy Klimatologii Polarnej
• Rocznik: 2003
• Tom: nr 13
• Strony: 43--58
• Opis fizyczny: Bibliogr. 18 poz., rys., tab.

Twórcy

autor

Marsz A. A.

• Akademia Morska w Gdyni Katedra Meteorologii i Oceanografii Nautycznej,

Bibliografia

• 1. Hurrell J.W., 1995, Decadal trends in the North Atlantic Oscillation: Regional temperatures and precipitation. Science, vol. 269: 676-679.
• 2. Jones P.D., Jonsson T., Wheeler D., 1997, Extension to the North Atlantic Oscillation using early instrumental pressure observations from Gibraltar and South-West Iceland. Int. Journal Climatol. 17: 1433-1450.
• 3. Marsz A.A., 1987, Brzegi lodowe. Ossolineum. Wrocław, Warszawa, Kraków, Gdańsk, Łódź: 118 s.
• 4. Marsz A.A., 1997, Współdziałanie klimatyczne między strefą tropikalną a północną częścią strefy umiarkowanej, strefą subarktyczną i arktyczną wzdłuż brzegów zachodniej części Północnego Atlantyku. Probl. Klimat. Polarnej, 7: 167-234.
• 5. Marsz A.A., 1998, Problem metody sporządzania długoterminowej prognozy występowania gór lodowych na orto-dromie północnoatlantyckiej. Prace Wydziału Nawigacyjnego WSM w Gdyni, z. 6: 146-165.
• 6. Post L.A., 1956, The role of Gulf Stream in the Prediction of Iceberg Distribution in the North Atlantic. Tellus, 8: 102-111.
• 7. Report of the International Ice Patrol in the North Atlantic. 1991 Season. Bulletin No 77. CG-188-46. US Coast Guard: 51 s.
• 8. Report of the International Ice Patrol in the North Atlantic. 1992 Season. Bulletin No 78. CG-188-47. US Coast Guard: 45 s.
• 9. Report of the International Ice Patrol in the North Atlantic. 1994 Season. Bulletin No 80. CG-188-49. US Coast Guard: 67 s.
• 10. Rogers J.C., 1984, A comparison of the mean winter pressure distribution in the extremes of the North Atlantic Oscillation and Southern Oscillation. Studies in Climate. Ed. H. van Loon. NCAR Technical Note 227, Atmospheric Analysis and Prediction Division. Boulder, Co.: 208-241.
• 11. Styszyńska A., 2001, Zmiany zlodzenia mórz Barentsa i Grenlandzkiego w świetle zmian wskaźnika intensywności Prądu Labradorskiego. Probl. Klimat. Polarnej 11: 93-104.
• 12. Sukhovej V.F. 1977, Izmenčivost' gidrologičeskikh uslovij Atlantičeskogo okeana. Naukova Dumka. Kiev: 215 s.
• 13. The Encyclopedia of Oceanography, 1966, Ed. R.W.Fairbridge. New York.
• 14. Trivers G., 1994, International Ice Patrol's Iceberg Season Severity. Report of the International Ice Patrol in the North Atlantic. 1994 Season, Bulletin No. 80. CG-188-49. US Coast Guard: 49-59.
• 15. Viekman B.E., Baumer K.D., 1995, International Ice Patrol Icebergs Limits Climatology (1975-1995). International Ice Patrol Technical Report 95-03. US Coast Guard: 20 s.
• 16. International Ice Patrol Data Base. National Snow and Ice Data Center. Boulder, Co. (NSIDC) http://www.rdc.uscg.mil...ages/data/icebergs.html (dane IIP US Coast Guard o liczbie gór lodowych, ostatnia modyfikacja 15.02.2000),
• 17. CD-ROM 994800 - GEDEX, Disc 1, NASA (zbiór danych średnich miesięcznych temperatur powietrza),
• 18. ORNL/CIDAC-53 (Oak Ridge National Laboratory, dane „The Global Climatology Network”: postać elektroniczna)