Welcome to the  
SMAPEx-3 Archive
Soil Moisture Active Passive Experiment
 

Soil Moisture Sampling

Spatial ground sampling of soil moisture was undertaken concurrently with each regional flight during SMAPEx-3. During regional flights, sampling was undertaken on a regular grid of 250m-spaced locations in two 3km x 3km focus areas. At each location three surface soil moisture measurements were taken. This allows the effect of random errors in local scale soil moisture measurements to be minimised. Complete details on the soil moisture sampling strategy and protocols can be found in the SMAPEx-3 workplan.

Soil Moisture Sampling Overview

soil moisture sampling overview


HDAS soil moisture measurements

The soil moisture data collected at each focus area are shown in the overview below. Users can download the data of the corresponding patch via the Download Centre .

Day 05-09-2011_Regional Flight

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Day 07-09-2011_Regional Flight

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Day 10-09-2011_Regional Flight

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Day 13-09-2011_Regional Flight

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Day 15-09-2011_Regional Flight

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Day 18-09-2011_Regional Flight

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Day 19-09-2011_Regional Flight

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Day 21-09-2011_Regional Flight

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Day 23-09-2011_Regional Flight

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Hydraprobe Data Acquisition System

Soil moisture measurements during SMAPEx were undertaken using the Hydraprobe Data Acquisition System (HDAS), a powerful spatial data acquisition tool developed by the investigators which integrates a handheld Pocket PC, a Stevens Water Hydraprobe and a GPS receiver into a mobile GIS environment. This system allows navigating to predefined sampling locations and collecting and storing in real-time a variety of spatial data, including the soil moisture, soil temperature and soil salinity provided by the probe as well as a variety of user-prompted observations (land cover type, vegetation canopy height, visual observation of dew presence, visual estimate of surface rock cover fraction, irrigation type).

Hydraprobe Calibration

The soil moisture calibration equation for the HDAS was derived from the analysis of a large number of laboratory and field gravimetric samples collected in previous campaigns by Merlin et al (2007). The quality of the calibration was confirmed by analysis of gravimetric data from the SMAPEx and related AACES experiments.

HDAScal

 

Created: July 2010
Last Modified: April 2012
Maintainer: Xiaoling Wu, xiaoling.wu@monash.edu