HR: 16:00h
AN: A24A-01 INVITED     [Abstracts]
TI: Synoptic Conditions in Winter in the Arctic and Their Relation to Pollution Transport into the Arctic
AU: * Stohl, A
EM: ast@nilu.no
AF: Norwegian Institute for Air Research (NILU), Instituttveien 18, Kjeller, 2027 Norway
AB: This paper will give an overview of the meteorological conditions in the Arctic and how they are related to the transport of pollutants into the Arctic and their removal from the Arctic atmosphere. In winter, potential temperature surfaces (isentropes) form closed domes in the Arctic, thus separating the lower Arctic troposphere from the rest of the atmosphere. Apart from some high-latitude pollution sources that are located within the Arctic, pollution can enter the polar dome only via strong cooling of air masses in the ice-covered (mostly Eurasian) sub-Arctic boundary layer, and radiational cooling and slow descent of upper tropospheric air masses. However, once pollution is present within the polar dome, its residence time can be much longer than anywhere else because the Arctic atmosphere is extremely dry and characterized by a highly stable stratification, thus rendering removal mechanisms very inefficient, and leading to pollution phenomena such as the Arctic Haze. Air masses, especially in the Canadian sector of the Arctic, can also have resided in complete darkness for weeks, thus shutting off photochemical processes. Synoptic conditions are also strongly influenced by the Arctic (or North Atlantic) Oscillation, which in its positive phase leads to enhanced transport of pollution into the Arctic.
DE: 0368 Troposphere: constituent transport and chemistry
DE: 1631 Land/atmosphere interactions (1218, 1843, 3322)
DE: 3349 Polar meteorology
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005