Skaha's Land-Surface Model

The algorithm is based on published, peer-reviewed papers.
Obtains satellite and soil data from Google Earth Engine.
Hourly weather data downloaded from tomorrow.io.
Optimized using reference data from over 1000 TDR probe measurements collected over five years across fields in Canada.
Used internally by Skaha to calibrate microwave data and provide customers with soil moisture status and forecasts.

Global digital elevation data from the Shuttle Radar Topography Mission at a resolution of 30 meters.

The topographic wetness index is calculated from elevation data for each field and is used to simulate the distribution of water.

From OpenLandMap we receive clay content and soil texture information and derive maps of field capacity and permanent wilting point with 250 meter resolution.

CFSv2 (Climate Forecast System Version 2) is used to collect historical data for each field, going back 250 days. If available, more accurate weather data from tomorrow.io is used. Based on satellite data and precipitation records, evapotranspiration and water balance are calculated.

NDVI (Normalized Difference Vegetation Index) and MSI (Moisture Stress Index) maps are calculated from Sentinel-2 data.

The model provides daily maps of Volumetric Water and Plant Available Water Content.

Documentation

Accuracy

Validated against more than 1000 reference data points gathered with a mobile soil moisture probe over four years and across 25 fields in Canada, including multiple surveys across different crops and growth stages. Our model accurately predicts soil moisture with an error of 0.05 cm³/cm³.

Open Documentation

The model is grounded in scientific research published in academic journals, with any alterations and improvements documented on our wiki pages.

We're open to collaborating with users who wish to incorporate their own soil or elevation data into the model.

GPS Tracker for Centre-Pivots

For irrigated fields, we provide a GPS tracker that can be affixed to the outer span of a centre pivot. This tracker serves to update the model with information on recent irrigation activities. The tracker operates for multiple years on a single battery pack.

Periodically Updated and Improved

Whenever we gather soil moisture data using our mobile probes, this data is integrated into our land surface model to enhance its accuracy. As a result, the model is continually refined through the accumulation of data across various seasons, soil types, and continents.

For Irrigated Fields

In order to keep track of irrigation events, we provide GPS tracking devices that need to be attached to the pivot and record pivot motion. Using the angular speed of the pivot along with the (user-provided) pump rate, we estimate irrigation depth.

Our trackers are equipped with long-lasting batteries and are easily attached to the outer spans of a center pivot. Through a cellular data link, position data are uploaded to our servers.

This application does not require the use of microwave sensors. The model output is an estimated soil moisture based on satellite and weather data.

Up-to-date soil moisture status is calculated and sent out via email every 1-3 days (user-configurable). The email contains the average field moisture level, estimated evapotranspiration, rain forecast, and a predicted water balance for the next 4 days. Also sent out are maps of simulated plant-available water, moisture stress index from Sentinel-2, as well as graphs showing moisture for the dryest and wettest location of the field.

For Dryland Fields

We can simulate soil moisture for any un-irrigated field across the globe.

This is a service primarily intended for agricultural businesses or consultants, interested in obtaining simulated moisture maps for their fields.

Please contact us for details.

Pricing

For Irrigation

Annual subscription: $190

One-time charge for GPS Tracker: $300

(in Canadian Dollars)

For Dryland

Please contact us to discuss.