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They are global algorithms, based on similar assumptions, and use the blue-green band ratios. Chlorophyll algorithm is a little complicated with the blend of a band difference and band ratio algorithms.

Hello, if you downloaded the data from oceancolor website, to better help with this question, can you share one of the file's name you have got? This will help us identify which level (L2 or L3) and what format of data you are using.

You can find the information on the following ATBD and the corresponding reference:
https://www.earthdata.nasa.gov/apt/documents/chlor-a/v1.0#doc-header

@tlin2_cuny.edu @haag
Please email "connection_problems@oceancolor.gsfc.nasa.gov" with the public ip address you are connection from, the time you tried to connect and a short description of the network issue you are experiencing. The NASA OBPG network team will assist you.

Please email "connection_problems@oceancolor.gsfc.nasa.gov" with the public ip address you are connection from, the time you tried to connect and a short description of the network issue you are experiencing. The NASA OBPG network team will assist you.

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...