Thesis subject
MSc thesis topic: Irrigation detection from space
Crop growth models combined with weather forecasting are used by farmers to plan their irrigation activities. Models predict when and in which fields drought is upcoming. Farmers then plan where and when to irrigate. Currently the advice is often inaccurate, due to lack of accurate irrigation input data at field level. Satellites can measure soil moisture but cannot forecast future crop water needs and future rainfall. Models fill this gap but lack accurate irrigation input data, real-time that is when and how much was irrigated in the ongoing season. During the growing season farmers are often busy with other more urgent activities, too busy to immediately enter their data.
A possible solution to this data problem is automatically estimate irrigation date from satellite data so that we no longer have to ask the farmer. If today soil moisture suddenly increases according to the satellite and if today there is no rainfall, then that must have been due to irrigation. Or it could be that the weather data are wrong, for example using one of 15 KNMI weather stations could be less accurate than using high resolution rainfall data from e.g. buienradar. In this thesis you will work with new high resolution daily satellite soil moisture data (source: OnePlanet) in combination with weather data (different sources) and crop growth models. The objective of this thesis is to test if irrigation dates, and possibly amounts, can be estimated from combining soil moisture and rainfall data. You will validate the irrigation predictions with actual irrigation from several farms in the Netherlands and in Brazil.
Relevance to research/projects at GRS or other groups
Co-supervised by GRS and Agrosystems Research. https://www.wur.nl/en/research-results/research-institutes/plant-research/business-units/agrosystems-research-1.htm
Objectives and Research questions
- How accurately can irrigation events at field scale be detected?
- How accurately can irrigation amounts at field scale be detected?
Requirements
- Programming languages: R (required), SQL (preferred)
- Basic knowledge of what is a time series
- Basic knowledge of soil physics (upper and lower limit, saturation)
Literature and information
Planet soil moisture product
- https://assets.planet.com/docs/Soil_Water_Content_Validation_Whitepaper.pdf
- https://developers.planet.com/docs/planetary-variables/soil-water-content-technical-specification/
Soil moisture measurement from satellite
- de Jeu et al. 2001: A Methodology for surface soil moisture and vegetation optical depth retrieval using the microwave polarization difference index (no need to understand the mathematics behind it)
Expected reading list before starting the thesis research
On estimating irrigation from soil moisture
- Brocca et al 2023: How much water is used for irrigation? A new approach exploiting coarse resolution satellite soil moisture products - ScienceDirect
- A Review of Irrigation Information Retrievals from Space and Their Utility for Users (mdpi.com)
Theme(s): Sensing & measuring; Modelling & visualisation