From June 7 to July 17, the U.S. National Aeronautics and Space Administration (NASA) will fly two piloted aircraft several times a week over an area of mixed agricultural and forested land from Portage la Prairie to Carman in south-central Manitoba. These aircraft will carry instruments similar to those onboard a satellite that NASA will launch in 2014.
Heather McNairn, an Ottawa-based AAFC research scientist and principle investigator for the project, said her team’s work will involve pre-launch calibration and validation of the high-tech equipment.
“You want to make sure that the algorithms and models that you’re using are working properly so that the first data that comes down is usable data,” she said.
Once in space, NASA’s Soil Moisture Active Passive (SMAP) satellite will measure surface soil moisture and temperature that will be used to produce maps of global soil moisture, temperature and freeze/thaw states on a regular basis by bouncing microwaves off the surface of the Earth.
These maps will help researchers monitor surface soil moisture conditions that affect agricultural production and update models used to predict crop yields. The new information will likely be made available via a free-access web portal.
McNairn added that it could help Canadian producers make informed farm-operation decisions based on changing weather, water and climate conditions, and assist grain traders and governments in predicting global grain yields.
The satellite will be able to measure surface soil moisture to a depth of five to 10 cm. Other testing will look at the potential for modelling moisture down deeper as well, she said.
Currently, data on soil moisture is “sparse.” The researchers will use an existing AAFC in-situ soil probe within the test area that covers depths from 20 cm, 50 cm, and one metre, to test how well the satellite equipment works.
“NASA’s intent is to cover the whole Earth,” said McNairn, adding that the raw data will be made freely available globally to create “value-added” products showing surface and root zone soil moisture levels by region. For governments, the data could help pinpoint lost acres due to floods or drought.
“It could be used for just about anything, such as determining in spring whether it’s the right time to seed or go on the field,” she said. “Then through the growing season, it could be used to look at issues around drought and crop yield potential.”
During the field campaign, or validation experiment called SMAPVEX, scientists will be calibrating the models that will be used to estimate soil moisture from the satellite. To do this, scientists will be taking measurements on the ground for soil moisture and temperature, plant biomass and surface roughness.
More detailed information about the plant canopy, such as plant spectral properties and leaf area index, will also be collected. These traits indicate plant growth and yield potential by measuring leaf development and the amount of light intercepted by plant leaves.
In addition to the collection of field data, 50 temporary soil moisture monitoring stations will be installed to provide continuous measurements over the six weeks of SMAPVEX. Last year, AAFC installed permanent soil monitoring stations on a number of private farms in the area, which will serve as a long-term site for assessing the satellite data after the launch.
To date, 70 field and aircraft crew are expected to be in the field during SMAPVEX. The participation of producers in the Portage la Prairie–Carman area will contribute in no small way to the success of the project, and ultimately to the success of the satellite mission, AAFC added in a press release.
Manitoba was chosen for this project due to the extreme variability in soil moisture that typifies the Red River watershed.
The Manitoba site also has a range of crop types, both annual and perennial, land cover such as farmland, wetlands and forest land, as well as soil texture.