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Hello, The POC algorithm is mainly for open ocean or Case 1 waters, and it relies on the fact that variation in Rrs(λ) at blue wavelengths are primarily driven by phytoplankton pigments and covarying matters. For coastal or optically complex case 2 waters, the empirical relationship used in the algo...

Hi, First of all, here is the theoretic basis for the standard Chlorophyll-a algorithm we use: https://oceancolor.gsfc.nasa.gov/resources/atbd/chlor_a/. Second, yes, for coastal regions, the standard Chlorophyll-a values tend to be higher due to the optical complexity of the water. That said, the op...

Hi Anna,

ERDDAP database is maintained by NOAA. You may want to try Earthdata Search (https://search.earthdata.nasa.gov/search).

Let me know if you came across any issues.
Guoqing

Hello, We are working on sample python scripts for such purposes. These scripts will be available very soon, but here is an example to get you started: L3 data is stored as variables, and you can use xarray to read them: import xarray as xr # use the following file as an example filename = 'AQUA_MOD...

Hi, The discrepancies you've observed primarily stem from comparing local min/max values to global ones. When you download without extraction, you receive the Chlorophyll image for the entire globe. On the other hand, using the extract function allows you to isolate the specific region defined by th...

Hi Giovanni, You can find all the information regarding the quality flags on this webpage: https://oceancolor.gsfc.nasa.gov/resources/atbd/ocl2flags/ If you are using the L2 products, the flags and masks are included in the file. One easy way to find those info is opening the data file in SeaDAS. Fo...

Hi Josep,

It seems the files were located on our server but the downloading was incomplete. Do you mind trying to use the app key and let us know how it works? You can find more details on this page: https://oceancolor.gsfc.nasa.gov/data/download_methods/

Hey,

If you came across data related questions or issues to report, our experts will be able to help; but for data analysis related scientific questions for a particular region, you got to figure it out by yourself.

Uma,

Here is a help page about SNAP time series management:
https://seadas.gsfc.nasa.gov/help-8.3.0/timeseriestool/TimeSeriesManager.html

Hope it helps.
Guoqing

Hi, sorry for the delayed response. And sorry that I can't debug your code, but have you noticed similar patterns in our L3 MODIS Aqua chlorophyll images? If so, please provide more details. Otherwise, you may want to check your code for the way that you count the NAN at the same pixel/bin/location.