Willmott and Feddema's Moisture Index Archive:
Monthly Time Series (1900 - 2014)

(Version 3.01)

produced and documented by

Cort J. Willmott and Kenji Matsuura
[with support from NASA's Innovation in Climate Education (NICE) Program]

For additional information concerning this archive,
please contact us at:

Department of Geography
University of Delaware
Newark, DE 19716
(302) 831-2294

or

kenjisan@udel.edu


Archive (Version 3.01) released in May, 2015


GRIDDED DATA SOURCES:

Time series of gridded monthly potential evapotranspiration (Eo) and total precipitation (P) were taken from the Terrestrial Water Budget Data Archive: Monthly Time Series (1900-2014) (Version 3.01) and the Terrestrial Air Temperature and Precipitation: Monthly Time Series (1900-2014) (Version 4.01) archive, which also are available from this web site. The length of each grid-node time series is 115 years (from 1900 through 2014) and the grid points, which number 85,794, cover the land surface at a 0.5x0.5 degree resolution.

GRIDDED WATER-BUDGET ESTIMATES:

Monthly moisture-index fields were estimated from the gridded monthly Eo and P fields according to Willmott and Feddema (1992) at the same resolution as the water-budget fields.

ARCHIVE STRUCTURE:

There is one file (im_2014.tar.gz) that includes the 115 yearly files. All yearly files have the same structure (once they are uncompressed). Please note that annual moisture index was computed from the 12-month totals of Eo and P.


Field Columns Variable Fortran Format
1 1 - 8 Longitude (decimal degrees)
F8.3
2 9 - 16 Latitude (decimal degrees)
F8.3
3-14 17 - 112 Monthly Moisture Indices
12F8.2
15 113 - 120 Annual Moiture Indices
F8.2


SELECTED REFERENCES:

Willmott, C. J., C. M. Rowe, and Y. Mintz, 1985b. Climatology of the Terrestrial Seasonal Water Cycle. Journal of Climatology, 5, 589-606.

Willmott, C. J. and J. J. Feddema, 1992. A More Rational Climatic Moisture Index. Professional Geographer, 44(1), 84-88.