This dataset compromises chlorophyll data, which was collected using a Special Products Analysis Division (SPAD) 502 chorophyll meter, as part of the Network for Calibration and Validation of EO data 2006 Field Campaign. The estimates of chlorophyll amount were taken for the spring barley crop in Brockley field, near Chilbolton, this having been the only available field without seed heads and subsequently appropriate for measurements to be taken from. The numerical SPAD value is proportional to the amount of chlorophyll within the leaf, but a calibration equation for Spring Barley is required to convert these values into chlorophyll concentration. Each SPAD value in the file is an average of 10 values which were measured within 10 metres of the flag.