Operational Monitoring of Daily Crop Water Requirements at the Regional Scale with Time Series of Satellite Data

This work presents a simple, cost-effective and operational approach to monitor crop water requirements at the regional scale for water management and monitoring purposes. The recommended FAO-56 methodology calculates crop evapotranspiration using crop-specific coefficients (Kc), which vary according to the crop type, health and phenological stage. This approach, though widely applied for irrigation planning, cannot always match the appropriate crop coefficient with the actual crop phenological stage and health condition, especially in anomalous situations. Previous research demonstrated that crop coefficients and spectral Vegetation Indexes are correlated. Recent studies have used this relationship with high resolution satellite data from different sensors to provide information to irrigation advisory services. However, high resolution data are not feasible for an operational and routine monitoring of water consumption and needs. This paper tests the usefulness of time series of coarse resolution satellite data such as those collected by the MODIS sensor, to monitor crop coefficients temporal and spatial variability and therefore crop water needs at the regional scale taking advantage of the peculiar characteristics offered by MODIS in terms of high temporal resolution and pre-processed products availability. The outlined methodology takes into account the actual growing stage of the crops and nearly real-time vegetation variations, overcoming some limitations of the traditional FAO approach while preserving the maximum operability. The analysis was carried out in the South Milan agricultural area on data referring to 2003 and 2004. The results agreed with those of other studies, and proved to be able to account for the anomalous conditions of the summer in 2003. These results were then compared with those obtained using the traditional FAO crop coefficient curves built with data collected during field campaigns in the same years in rice fields. Constraints, limitations and possible uses are discussed.

ROSSI Simone;  RAMPINI Anna;  BOCCHI Stefano;  BOSCHETTI Mirco; 

2010-03-25

ASCE-AMER SOC CIVIL ENGINEERS

JRC52458

0733-9437,   

https://publications.jrc.ec.europa.eu/repository/handle/JRC52458,   

10.1061/IR.1943-4774.0000161,