Satellite-Observed Changes in Energy Advection within the Arctic (formerly paper number 1.19)

The Arctic environment has clearly undergone significant change during recent decades, e.g., the Arctic Oscillation (AO), but it is unclear how this change is related to other variables, such as the magnitudes and pathways of energy advected from lower latitudes. Unraveling the causes and linkages is a challenging task. Conventional meteorological data are sparse over the Arctic Ocean, and other than surface pressure fields and temperatures, we have relatively little ammunition with which to investigate these issues in a pan-Arctic sense. The recently available satellite-derived NASA/NOAA TOVS (TIROS Operational Vertical Sounder) Polar Pathfinder (Path-P) data set provides a new window to the Arctic by providing spatially and temporally high-resolution retrievals of atmospheric and surface quantities spanning 18 years. Because the primary link between the Arctic and the global climate system is laterally advected heat in the atmosphere, the focus of this preliminary study is to explore patterns and trends in the convergence of sensible heat (SHC) in the Arctic atmosphere computed from Path-P product. Heating rates [K/day] are calculated by combining thickness fields, computed from Path-P temperature profiles, with upper-level winds obtained from NCEP Reanalysis data. Fields for three thick tropospheric layers are calculated each day at (100 km)2 resolution north of 60N. In addition, we separate the poleward component (positive when heat is transported northward or cold southward) and the zonal component (positive when heat is transported westward or cold eastward) of the SHC. Many of the changes observed in the Arctic environment have occurred most noticeably since the late 1980s. We explore the behavior of SHC during this period by computing the difference between the means before and after 1989. Preliminary calculations suggest that the interdecadal differences are large and cohesive. This presentation will focus on changing patterns in horizontal energy transport, and relationships between these patterns and the AO.