|
||||||
|
|
||||||
Monthly extent climatologies are intended for users interested in persistence of ice over a particular month during the time series, January 1979 through December 2007. The ice extent climatologies are derived each month from monthly-averaged sea ice concentrations using the NASA Team Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I Passive Microwave Data.
Individual ocean pixels containing a minimum of 15% ice cover are summed throughout the time series. The maximum ice persistence value is 100 percent. Each pixel represents the percentage of years for which ice was present.
Data are stored in two-byte integer format. For the Northern Hemisphere the grid size is 304 x 448 pixels, and the Southern Hemisphere grid size is 316 x 332 pixels. Land is set to a value of 254 and coastlines to a value of 253. Ice extent climatologies are computed for each month with file names structured as persistence.month.yyyy1-yyyy2.n (or .s), where yyyy1 represents the first year for which data was available, and yyyy2 represents the last year for which data was available in computing the ice persistence information.
Example: the file persistence.jan.1979-2007.n contains ice persistence information for the Northern Hemisphere during January, for the full time series, 1979 through 2007.
Corresponding PNG images of ice persistence are also provided.
| Data are availabe via FTP |
