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Optimal spatial sampling techniques for ground truth data in microwave remote sensing of soil moistureThe paper examines optimal sampling techniques for obtaining accurate spatial averages of soil moisture, at various depths and for cell sizes in the range 2.5-40 acres, with a minimum number of samples. Both simple random sampling and stratified sampling procedures are used to reach a set of recommended sample sizes for each depth and for each cell size. Major conclusions from statistical sampling test results are that (1) the number of samples required decreases with increasing depth; (2) when the total number of samples cannot be prespecified or the moisture in only one single layer is of interest, then a simple random sample procedure should be used which is based on the observed mean and SD for data from a single field; (3) when the total number of samples can be prespecified and the objective is to measure the soil moisture profile with depth, then stratified random sampling based on optimal allocation should be used; and (4) decreasing the sensor resolution cell size leads to fairly large decreases in samples sizes with stratified sampling procedures, whereas only a moderate decrease is obtained in simple random sampling procedures.
Document ID
19780034338
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Rao, R. G. S.
(Kansas Univ. Center for Research, Inc. Lawrence, KS, United States)
Ulaby, F. T.
(University of Kansas Center for Research, Inc., Laurence Kan., United States)
Date Acquired
August 9, 2013
Publication Date
January 1, 1977
Publication Information
Publication: Remote Sensing of Environment
Volume: 6
Issue: 4, 19
Subject Category
Earth Resources And Remote Sensing
Accession Number
78A18247
Funding Number(s)
CONTRACT_GRANT: NAS9-14052
Distribution Limits
Public
Copyright
Other

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