JISAO data

Merged surface air temperature data 1950-99
(most complete coverage 1979-97)

Introduction | Data

For the study of high-latitude Northern Hemisphere climate, a 1-degree latitude-longitude resolution data set is provided that is the merge of data from three sources. Land data is from the
University of Delaware (UD); marine data (primarily away from the Arctic) is from the Comprehensive Ocean-Atmosphere Data Set (COADS); and marine data primarily at the Arctic is from the International Arctic Buoy Programme and Polar Exchange at the Sea Surface (IABP/POLES). The merging of these data sets is documented below.

Satellite view of Arctic, Greenland, and North America.
PostScript | JPEG | digital values (netCDF)
"High index" values of the Arctic Oscilation (AO) (below normal Arctic sea-level pressure) is associated with below normal surface air temperatures in the Arctic, Greenland, Baffin Island, Alaska, and eastern Siberia, and temperatures more than 1C above normal in central Siberia, and Canada.

The merging process employed is simple, but yields a useful data set. There is certainly room for more sophisticated treatment.

The UD data (version 1.02) spans 1950-99, and its native resolution is 0.5-degrees latitude-longitude. I have averaged this data into a 1-degree latitude-longitude resolution version.

I am using the 1-degree latitude-longitude version of COADS ("enhanced" quality control), and this spans 1960-97. There are spurious observations in (41-46N,175-170W; 41-46N,165-160W), and I have replaced these with interpolated values.

The IABP/POLES data provides values for both land and sea for 1979-98. The grid is reminiscent of the old National Meteorological Center octagonal grid. I interpolated this data set onto a 1-degree latitude-longitude resolution grid, using the Cressman scheme with an e-folding scale of 1-degree latitude.

UD data is available for each month, COADS is put in for the marine observations, and IABP/POLES values are used to fill the remaining marine grid boxes. The contributions of COADS and IABP/POLES during the common years 1979-97 are shown below.

Satellite view of Arctic, Greenland, and North America.
PostScript | JPEG
COADS contributes fewer than 20% of the oservations in the Arctic. White shading for zero percent.

Data in netCDF format:
At JISAO: /home/disk/muggy/data/gridded_land_and_ocean_temp/merged_arctic/
  • monthly data (78 Mbytes)
  • 1979-97 climatology. Maps 1-12: January, February, ..., December climatologies; map 13 annual mean (all months contributed); maps 14-17: December-January-February, March-April-May, June-July-August, and September-October-November, respectively.


    December 2002
    Todd Mitchell ( mitchell@atmos.washington.edu )
    JISAO data