Impact of observations from Arctic drifting buoys on the reanalysis of surface fields
Jun Inoue1, Takeshi Enomoto2, Takemasa Miyoshi3, Shozo Yamane4
1Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology, Yokosuka, Japan
2Earth Simulator Center, Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan
3Department of Atmospheric and Oceanic Science, University of Maryland, College Park, Maryland, USA
4Department of Environmental Systems Science, Doshisha University, Kyotanabe, Japan
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Read the full paper (PDF): Geophys. Res. Lett., v. 36, L08501, doi:10.1029/2009GL037380, 2009. |
Abstract
We investigated the impact of Arctic ice-drifting buoys on an experimental ensemble reanalysis called 'ALERA'. The ALERA, where the buoy data are assimilated, includes the analysis ensemble mean and spread for each prognostic variable. In the data set, ensemble spreads of surface variables were found to be small only in the regions of densely aggregated buoys. Comparing the ALERA and the data set without the assimilation of surface pressure data observed by the buoys, differences in the ensemble mean and spread between two data sets were locally large, modifying air temperature and winds near the surface. Examining the effect of Arctic-buoy distribution on long-term reanalysis data sets, it was found that the amount of cross-ensemble spreads derived from common reanalysis is very sensitive to the number of buoys. This suggests that data set accuracy might be more vulnerable to deterioration in the near future due to fewer opportunities for buoy deployments over the sea ice.
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Figure 1. Analysis ensemble spread of SLP in August 2006 for (a) CTL (b) and ARC. Dots depict the positions of the Arctic drifting buoys. The thick line denotes ice concentration grater than 15%. |
