Accessing lat and lon for MODIS-Aqua 4km Chlorophyll

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Accessing lat and lon for MODIS-Aqua 4km Chlorophyll

by nicholeruiz » Thu Feb 22, 2024 5:23 pm America/New_York

I am trying to plot a map of monthly 4km res. chlorophyll data from MODIS-Aqua for one time step (using 2002-07-04 as a placeholder) using the cartopy package in python. The product I'm using is "Time Series, Area-Averaged of Chlorophyll a concentration (water only) monthly 4 km [MODIS-Aqua MODISA_L3m_CHL vR2022.0] (monthly)". I want to generate one plot per month per year, so I can create a gif of how chlorophyll distribution is changing over time in that area. The netcdf file for this product has the variables MODISA_L3m_CHL_Mo_4km_R2022_0_chlor_a, datamonth, shape_mask and time_bnds. Its coordinates are time.

My current code block (see attached) is plotting the data for 2002-07-04, but the same value is printing for the whole map, which I don't want. Is this because I am using an area-averaged product, so I would only have one value per time step? If so, should I be using a time-averaged product instead?

If this is not the case, how can I index the lat and lon to make my plot? Thank you in advance!
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ncdfvariables.png (192.9 KiB) Not viewed yet


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Re: Accessing lat and lon for MODIS-Aqua 4km Chlorophyll

by GES DISC - jimacker » Thu Feb 22, 2024 8:32 pm America/New_York


You could use Giovanni ( to create an animated GIF of the MODIS-Aqua monthly chlorophyll data product. Please reply for more guidance if this would be of interest to you.

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