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
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.
