Meridional energy flux in the Arctic from data of the radiosonde archive IGRA

Abstract

face to 30 hPa is 70.6 W m –2 . The fraction of the sensible heat flux is 23.2 W m –2 , i.e., 33% of the total energy flux; the fraction of the latent heat flux is 28.0 W m –2 (40% of the total energy flux); the fraction of the poten� tial energy is 20.0 W m –2 (27%); and the fraction of the kinetic energy is 0.53 W m –2 , i.e., less than 1% of the total energy flux. The vertical structure of the flux shows that the main energy transport into the Arctic takes place in the middle troposphere–lower stratosphere layer, whereas the energy is transported mainly out of the Arctic in the lower troposphere, which agrees well with the schematic notion about the polar circulation cell. The spatial structure of the flux shows that the key regions with a positive (directed into the Arctic) energy flux are located in the vicinity of 160° E (the northwestern part of Eurasia, Pacific sector) and 50° W (Green� land sector). The regions with a negative (directed out of the Arctic) energy flux are located near 120° W (Canadian Arctic Archipelago) and from 20° E to 90° E (Atlantic sector). In the period from 1992 to 2007, the meridional energy transport into the Arctic weakened by –0.26 W m –2 yr –1 . The changes were mutually correlated; namely, positive and negative energy fluxes weakened in amplitude, almost without changing their locations.