Introduction

The Data

Data and File Characteristics

The Science

Sampling Plan

Sampling Protocol

Temperature Sampling Procedure

Temperature Processing/IRT Calibration

Data Access and Contacts

FTP Site

Points of Contact

Information from the Little Washita fields (LW) 2-9, 12-14, and 21-27 have been collected and compiled into the attached files, each file labeled according to the field it represents. All of the attached summary files show the means of the raw temperature data for each field on each day. The data contained in these files is as follows:

The file lists the Site Number, Day (Month/Day/Year), Surface Temperature (T (surf)), Temperatures at depth 1cm, 5cm, and 10cm (all in degrees Celsius), land cover type (Range/Wheat/Corn/Alfalfa), Start time and end time of sampling for the field.

All data are in ASCII text.

Surface temperature (T (surf)) was collected using handheld infrared thermometers (IRT). All of the other temperature columns (T (1 cm), T (5 cm) , or T (10 cm)) were collected using temperature probes. There are a lesser number of temperature measurements for a 10 cm depth than at 1 and 5 cm depths due to the problem of probe tips breaking while trying to get measurements at the greater depth in an extremely dry soil.

For almost all of the fields there are no measurements for July 10, for it rained on this day. All temperature measurements at a field were taken within 3 hours of each other from day to day and all temperatures are measured in degrees Celsius.

Sampling Protocol

The temperature sampling was intended to estimate the field average. Precise location within the field was not important, however, to obtain meaningful statistics the samples were spatially distributed. A rectangular grid was set up for each field. Two types of sampling designs were employed, full and profile. The method of temperature sampling is the same for each design, but the number of samples is different.

Temperature Sampling Procedure

Full Sampling Fields. A full sampling field has a total of 14 points for soil moisture sampling set up in a rectangular grid. Points 1, 4, 11, and 14 of the soil moisture grid were sampled for temperatures.

Profile Sampling Fields. On a profile sampling field, 9 samples were collected at random locations around (and adjacent) the profile sampling stations.

Temperature Processing/IRT calibration

The surface temperature collected by the IRT (T_irt ) was modified to produce the surface temperature (T_s ) using an equation

T_s = A + B T_irt

This calibration was carried out for each individual IRT in a laboratory measurement. The resulting values of surface temperature (T_s ) are the reported values in the data (not T_irt).

The Soil Temperature data from SGP99 resides on DAAC anonymous FTP. You may access it from this document,

Soil temperature data (ASCII)

or directly via FTP at

ftp disc1.gsfc.nasa.gov

login: anonymous

password: < your internet address >

cd /data/sgp99/soil_temperature/

Points of Contact

The contact for details on temperature data is

For information about or assistance in using SGP99 DAAC data, contact