Download The implication of rapid Polar warming to the tropics

The implication of rapid Polar warming to the tropics.
Azizan Abu Samah Ph.D.
National Antarctic Research Centre,
c/o Institute of Postgraduate Studies,
University Malaya, Kuala Lumpur.
This paper highlights the results and discussion in the ICSU (ROAP) – SCAR forum on
rapid polar warming and its impact on the earth system on 23rd March 2007 in Kota
Kinabalu. This forum was held as part of the third Malaysian International Seminar on
Antarctica with a theme of From the Tropics to the Poles. In this meeting it was shown
that there are three observed hot spots where the temperature was observed to increase
rapidly two of the hotspots is in the Arctic while the third hot spot is in the Antarctic.
Analysis of the two hotspots in the Arctic linked the Alaskan warming to changes to the
Arctic Oscillation and the North Atlantic Oscillation from negative to positive phase
while for the Siberian warming it is linked to the phase change of the Pacific Decadal
Oscillations. In the case of the Antarctic Peninsular warming it is linked to the decrease
of sea ice and increase of westerlies associated with phase shift of the Southern
Oscillation Mode. An important lesson from the discussion is the complicated nature of
the process of change that can occur from global warming due to changes to the various
natural mode of oscillation such as AO, NAO, PDO and SAM in the high latitudes.
Turner showed that ENSO and La Nina has an impact on the SAM this also impact on the
strength of the westerlies and hence on the sea ice development in the Antarctic
Peninsular. Similarly ENSO and the AO has an effect on the strength on the Siberian high
in northern hemisphere summer. Azizan and Ooi showed that during ENSO period the
meriodinal component of the winter monsoon weakens, resulting in a more zonal
easterlies. This will impact in the rainfall intensity and onset of the northeast monsoon
over our region. Hence it is expected that the winter monsoon will have a stronger
variation with the rapid of warming the Siberian Arctic. However as shown in the study
of Turner climate variations to the tropics related to the warming of the poles will be
more complex and need further research.