Satellite data predicts lower wheat crop yield27 September 2022
© Manfred Richter (Pixabay)
Edited content from ESA
A critical stage in the growth of wheat is the jointing stage - when the growth moves above the soil surface. Therefore, any soil moisture stress in the spring can negatively impact crop health and cause crop loss.
Satellite data has proven instrumental in tracking droughts and predicting wheat crop yields.
The soil moisture-based drought monitor, developed in the framework of the EU’s H2020 ACCWA project shows better spatial resolution than existing drought monitors.
This drought monitor uses long-term datasets from the L-band measurements provided by the Soil Moisture and Ocean Salinity (SMOS) mission, which offer global observations of variability in soil moisture.
The drought index is based on SMOS Level 2 soil moisture products downscaled to a resolution of one kilometre.
During March 2022, extreme drought was measured by the drought monitor in the Ebro basin, a wheat growing region in Catalonia, northern Spain.
A methodology developed by the ACCWA team showed strong correlation between soil moisture drought indices and scarcity in crop yield production – results were presented at ESA’s Living Planet Symposium in Bonn 1.
Maria José Escorihuela, Principal Investigator for the ACCWA project at isardSAT, says: “Current drought observation warning systems offer maps of combined drought indices, derived from different data sources – meteorological measurements, satellite data and models. However, our work has shown that the anomaly of soil moisture in March is the best indicator for yield at the end of the season.
Extreme drought impact in the Ebro river basin in July 2022. Credit: isardSAT
Escorihuela adds, “The availability of a SMOS soil moisture long time series allows us to estimate the so-called “climate normality”. The drought monitor is based on soil moisture anomaly – the difference in soil moisture and the average over the 12 + year lifetime of the SMOS mission.
“Strictly speaking, when talking about anomalies in meteorology, you usually use a time period of 30 years, but we have seen it corresponds very well with a series of only 11 years.”
The monitor is updated monthly, but in collaboration with the Observatori de l’Ebre, the team also delivers a weekly drought bulletin zoomed in over the part of the Ebro river basin region, where traditional rain irrigated vineyards are cultivated.
Due to climate change projections, the vineyards are transitioning to irrigated wine production and rely on weekly information to support this transition.
As European markets strive to offset food insecurity, the timing of Europe’s dry spring couldn’t have been worse. For the Catalonian region alone, tons of cereals have been lost in this summer’s harvest.
Estimates for accumulated damages on the region’s wheat harvest are above nine million euro, due to the adversely dry spring. The results of the drought monitor have an immense value for multiple economic sectors and for society in general because they allow anticipating prevention and adaptation measures to mitigate future damages.
As summer heatwaves intensified in Spain, extremely dry soil moisture conditions emerged in the western part of the Ebro basin. The drought monitor captured this drought, highlighting water reservoirs at risk.
Whether it be helping predict wheat and wine production, or simply monitoring drought, the soil moisture data products from SMOS are a key tool in unravelling the impacts of our current climate crisis.