NOAA SEARCH Element 5: Observations for
SEARCH: Data Integration for Arctic Reanalysis
and Change Detection

PI: Florence Fetterer, NSIDC
PI: J. Overland
PI: R. Barry
PI: M. Serreze
PI: R. Armstrong
PI: T. Zhange

Abstract
Unaami, the changes in the Arctic that are the subject of the SEARCH program, became apparent to researchers in the context of long-term and pan-arctic observations. In November 2001, the SEARCH Workshop on Large-Scale Atmosphere/Cryosphere Observations reached two related conclusions: a) There is no cohesion among various Arctic disciplines and data types to form a complete observation set of Arctic change, and b) Present data are vastly underutilized in understanding Arctic change. The proposed work will address these conclusions by assessing what data are relevant to SEARCH reanalysis and change detection activities, collecting these data from a wide variety of sources, and facilitating the SEARCH research community's access to the data. The work will be carried out in cooperation with Jim Overland, PMEL, as a contribution to the NOAA SEARCH Arctic Change Detection and Reanalysis efforts.

There are many existing observational data sets that may be useful to SEARCH, but they are underutilized for reasons including
- Cover only a limited length in time or spatial extent
- Unknown accuracy, limited or no information about observing methods
- Not an ongoing record
- Inaccessible or costly to acquire
- Research community is unaware they exist

In addition to observational data sets, there are data streams that are underutilized. For example, only about 10% of the Russian national station network data are internationally exchanged over the GTS system and included in quality-controlled data sets available from U.S. national data centers.

These under-utilized data sources are not optimal because of the effort required to use them, but at the same time they can be vitally important to reanalysis and change detection efforts. For example, the planned Arctic reanalysis will assimilate precipitation data in order to improve how the model treats moisture. Yet precipitation measurements are especially problematic in the arctic, there are a number of data sets with differing characteristics, and a data stream for ongoing measurements has not been identified. Permafrost extent, borehole temperature and active layer depth are sensitive indicators of climate change and therefore good candidates for climate indices. These observations reside in a number of institutions around the world, and here the challenge will be to obtain and combine data sets into useful arctic-wide products.