The time series contain 36 values per year, with a code for missing data if data are absent. The data for 1978-1985 are a small part of the data which are published in annual reference books. Robock et al. Yang et al. Figure 1a shows an example of the data for the end of May 1985.
Winter cereals are the best analog for natural grasslands.
The number of stations used for spatial averaging for each district varied from about 10 to more than 100. This data set is the output of a system for monitoring soil moisture at agricultural fields of the former Soviet Union. Gravimetric soil moisture observations from about 600 agrometeorological stations were used as the basis for the data set. We are now working to make all the data for 1958-1996 available to the scientific community, and they will soon be available at the same WWW site. As an example, Figure 1c displays maps of soil moisture content at agricultural fields with spring cereals for the end of May 1987.