Page 1GlobColour CDR Meeting – July 10-11, 2006, ESRIN Overview of the operational solutions with feedback on what was proposed during the SRR meeting Samantha Lavender

Page 2GlobColour CDR Meeting – July 10-11, 2006, ESRIN Comparison to Requirements Baseline A prerequisite for data merging will be to perform a characterisation of the data from each of the input sensors [RB ]. –Have performed a characterisation for MERIS, MODIS and SeaWiFS. –Parasol data not made available for this purpose at present.

Page 3GlobColour CDR Meeting – July 10-11, 2006, ESRIN Comparison to Requirements Baseline Characterisation: –Calibration should cover the entire spatial and temporal extent of the data set [RB ]. –Both time and space variations in sensor calibration and sensor intercalibration shall be characterised [RB ]. Have performed: –In situ characterisation for MERIS, MODIS and SeaWiFS primarily from 2002 onwards. –Sensor cross characterisation using GlobCOLOUR level3 products for 4 dates in 2003 and linked to longer time scale conclusions from the JRC report.

Page 4GlobColour CDR Meeting – July 10-11, 2006, ESRIN Comparison to Requirements Baseline The characterisation shall also be used to cross- calibrate the systematic biases and differences in gain between sensor systems before merging [RB ] –Propose to currently use: normalised water leaving radiance: GlobCOLOUR chlorophyll: NASA (will split GlobCOLOUR into low/high groupings) diffuse attenuation coefficient: GlobCOLOUR –Will not aim to correct different sensors for biases, but propagate these through the merging techniques so that they can be represented by the error bars.

Page 5GlobColour CDR Meeting – July 10-11, 2006, ESRIN Comparison to Requirements Baseline Characterisation shall be performed on normalized water leaving radiance [RB ] and chlorophyll [RB ]. –Have performed characterisation for nLw, chlorophyll and the diffuse attenuation coefficient. nLw will undergo some further work in an attempt to improve the results –Currently only using MERIS Case I chlorophyll product: alternatively use MERIS Case II product in coastal waters.

Page 6GlobColour CDR Meeting – July 10-11, 2006, ESRIN Comparison to Requirements Baseline At least two different merging methods shall be implemented and tested during Phase 1 [RB ]. –Implemented average merging procedure and GSM01 technique. –A sensitivity analysis on chlorophyll concentration retrieval has been performed.