SCS-LTER Collaboration

Network News Fall 1991, Vol. 10 No. 1
Network News

Estimates of LTER Soil Moisture and Temperature Regimes

The U.S. Department of Agriculture (USDA) Soil Conservation Service (SCS) has prepared individual computer simulations of soil moisture and temperature for stations close to the LTER sites. The computation of soil climatic parameters and classification of soil moisture and temperature regimes is based on climatic data provided by the National Oceanic and Atmospheric Administration (NOAA). These cimatological normals (NOAA 1982) are based on records for the 30-year period 1951-1980.

A normal of a climatological element is the arithmetic mean computed over a time period spanning three consecutive decades. Homogeneity of instrument exposure and station location is assumed. If no exposure changes have occurred at a station, the normal is estimated by averaging the 30 values from the 1951-1980 record.

The model also estimates the duration, commencement and end of the growing season, which is considered as the period when there is no temperature or moisture stress. A Moisture Stress Severity Index (MSSI), a Temperature Stress Severity Index (l’SSI), and a Climate Stress Severity Index (CSSI) are also estimated. Additionally, for a few of these stations, the SCS has long-term climatic data based on which the probability of events have been calculated. These are not included in the simulation, but are available on request.

Actual climatic data for LTER site collaborators can also be computed. The information needed is:

  1. Name of station
  2. Latitudel
  3. Longitude
  4. Elevation (m)
  5. Monthly precipitation (mm)*
  6. Monthly temperature (°C)*. (*yearly, as many years as possible.)

For further information, or a copy of the simulation, contact Lawson Spivey, US Department of Agriculture Soil Conservation Service, 14th & Independence Aves. SW, Washington, D.C. 20013, 202-720-6371.