THE L-BAND PBMR MEASUREMENTS OF SURFACE SOIL-MOISTURE IN FIFE

The NASA Langley Research Center's L-band push broom microwave radiometer (PBMR) aboard the NASA C-130 aircraft was used to map surface soil moisture at and around the Konza Prairie Natural Research Area during the four intensive field campaigns of FIFE in May-October 1987. There was a total of 11 mea.urements over an area of 7 × 14 km during this period. One of the measurements was made on May 28 when soils were known to be saturated. This meaurement wa. used for the calibration of the vegetation efect on the microwave absorption. Based on this calibration, the data from other measurements on other days were inverted to generate the soil moisture maps. A good agreement was found when the estimated soil moisture values were compared to those independently measured on the ground at a number of widely separated locations. There was a slight bias between the estimated and measured values, the estimated soil moisture on the average being lower by ahout 1%. This small bias, however, was accounted for by the diference in time of the radiometric measurements and the soil moisture ground sampling. © 1990 IEEE