Inter-annual And Decadal Variability Of Sea Ice Change In The Arctic Ocean Regionally And Its Relationship With The Pressure-temperature Joint Mode

Thirty years (1979-2008) of Arctic ice products derived from satellitepassive-microwave data and corresponding atmosphere reanalysis products are usedto document sea ice variability in the Arctic Ocean regionally and its association withatmosphere circulation throughout the high latitude Northern Hemisphere.o finddifferences of sea ice change in different regions of the Arctic Ocean, Seven regionsin the Arctic basin were focused in this study: the Barents Sea, the Kara Sea, theLaptev Sea, the East Siberia Sea, the Chukchi Sea, the Beaufort Sea and the CanadianBasin. A sea ice relative area (SIRA) index was defined to present the ratio of the seaice in a certain region. With the value confined between0and1, SIRA is useful tocompare changes of sea ice among different regions. Envelopes of SIRA exhibitsignificant inter-annual variability of the sea ice, which provide us an efficient way toexplore the long-term change of the sea ice.Based on SIRA envelopes, two types wavelet transform and EMD method wereapplied and results suggest sea ice changes in all seven regions appear inter-annualvariability less than10years with the main frequency on the scale of2-8years and5-6year variability is active in several regions during some periods of time. Differentfrom that of other regions, sea ice change in the East Siberia Sea exhibit significantdecadal change on the period of about15years. Otherwise, the inter-annual variabilityof the sea ice in several regions changes frequency with time. In the Kara Sea, theLaptev Sea and the Beaufort Sea, the sea ice inter-annual variability changes from theperiod of7-8years to5-6years while in the Chukchi Sea and the Canadian Basin, thevariability varies from relative high frequency of5-6years to the frequency on the period of7-8years.Using the EOF method, the high latitudes1000hPa geopotential height-temperature joint mode are got which can well reflect the Northern Hemispherehigh-latitude changes of the temperature and pressure field. The joint mode of winterand that of summer state of their own independent existence. In the10-15yeardecadal scale, the summer joint mode affect the coincident changes of sea ice in theBarents Sea and East Siberian Sea while the Beaufort opposite and the coincidentchanges of sea ice in the Laptev Sea and Chukchi Sea while the Kara Sea opposite.Consistent changes of sea ice in the Barents Sea and East Siberian Sea are related tothe sea-level atmosphere temperature field associated to the summer joint mode whilethe opposite change of the sea ice between the East Siberian Sea and the Beaufort Seain the scale of10-15years are related to the sea level wind associated to the summerjoint mode. Consistent variability of sea ice in the Laptev Sea and Chukchi sea ice inthe scale of10-15years if opposite to that in Kara, which is mainly related tosea-level horizontal wind field associate with the summer joint mode.