SeaWiFS Reprocessing 5 Validation Analysis

The effect of the proposed SeaWiFS reprocessing changes on the comparison with in situ data are presented here. The difference in N between the operational and reprocessing sets is due to additional data added since the last time the operational set was run. Given the large sample sizes, the statistics should be comparable despite the differnce in N. A description of the methods employed for these analyses, with minor modifications, can be found in Volume 10, Chapter 7 of the SeaWiFS Post Launch Technical Memorandum Series.
There are approximately radiance and chlorophyll matchups which pass all exclusion criteria.

Statistics Summary:

Current Operational Processing

Proposed Reprocessing

Band	N	Mean Ratio^*	% Difference^**	Bias	rms⁺
nLw_412	491	0.8748	22.564	-0.1477	0.4425
nLw_443	593	0.931	17.201	-0.0898	0.3546
nLw_490	551	0.955	14.140	-0.0659	0.3059
nLw_510	424	0.9584	13.476	-0.0542	0.3030
nLw_555	593	0.990	14.5190	-0.0132	0.2308
nLw_670	571	1.0764	47.836	0.0012	0.0731
chl	1267	1.106	35.908	0.104	0.7085

N	Mean Ratio^*	% Difference^**	Bias	rms⁺
523	0.9203	22.7320	-0.0683	0.3384
625	0.9572	17.189	-0.0316	0.2696
625	0.947	14.5180	-0.0443	0.2210
490	0.932	14.684	-0.0546	0.2110
625	0.9410	16.698	-0.0412	0.1785
590	0.9134	50.897	-0.0098	0.0678
1392	0.9610	36.473	-0.0456	0.7303

* arithmetic mean of all satellite / in situ ratios
** median absolute percent difference
+ sqrt ( &sum(satellite - in situ)^2 / n )
chlorophyll data were log transformed prior to statistics calculation

The Plots

Operational Radiances Chlorophyll
Proposed Reprocessing Radiances Chlorophyll

Discussion

Overall, there was little change with the in situ comparisons between operational (reprocessing 4) and the proposed reprocessing results. The biases were slightly reduced with the proposed reprocessing, although the median percent difference (absolute) are nearly identical between the two.

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Authorized by: gene carl feldman