Page 1 GlobColour 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 2 GlobColour 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-047.00].

– Have performed a characterisation for MERIS, MODIS and SeaWiFS.

– Parasol data not made available for this purpose at present.

Page 3 GlobColour 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-048.00]. – Both time and space variations in sensor calibration

and sensor intercalibration shall be characterised [RB-049.00].

• 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 4 GlobColour 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-050.00] – 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 5 GlobColour CDR Meeting – July 10-11, 2006, ESRIN

Comparison to Requirements Baseline

• Characterisation shall be performed on normalized water leaving radiance [RB-051.00] and chlorophyll [RB-052.00].

– 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 6 GlobColour 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-026.00].

– Implemented average merging procedure and GSM01 technique.

– A sensitivity analysis on chlorophyll concentration

retrieval has been performed.