Relationship Between CCI Soil Moisture Anomalies and Cereal Yields
Paulik, Christoph; Dorigo, Wouter; Wagner, Wolfgang; Chung, Daniel
Vienna University of Technology, AUSTRIA

The CCI soil moisture project aims to provide a consistent, global long term record of soil moisture observations derived from multiple satellites. Soil Moisture is an Essential Climate Variable and a key parameter in hydrology, meteorology and agriculture where it was found to be a good estimator of crop yield. In this study soil moisture data from the CCI project with a resolution of 0.25° spanning the years 1978 to 2010 was used to compute monthly and yearly anomalies. The anomalies over cropland were then compared to yearly cereal yield data from the FAO which was detrended to account for technological advances in farming technology. Significant linear relationships between soil moisture anomalies and cereal yields could be found for several regions including the USA, Australia and Spain and are especially pronounced where the Agricultural Commodity Diversification Index is low and cereals account for high percentages of total area harvested. Outliers of the resulting linear relationships occurred in very wet years which can lead to low cereal yields. These years could be identified by comparing the data to crop production summaries from the U.S Department of Agriculture and the Australian Department of Agriculture, Fisheries and Forestry. The obtained results offer a glimpse at the potential that consistent long term climate records hold for better understanding their relationships to other phenomena.