Earthdata Forum

Hello,

I have recently obtained CYGNSS data, but I am struggling to understand the concept and purpose of the Delay Doppler Map (DDM).

What exactly does a DDM represent in the context of CYGNSS?
How is it used for analyzing environmental conditions such as wind speeds, soil moisture, or flooded areas?
Are there any tutorials or examples available to better understand how to interpret and work with DDM data?
I would greatly appreciate any guidance, resources, or tools to help me get started with understanding and using DDMs effectively.

Thank you!

Hi,

Dean here from PO.DAAC (we host the CYGNSS data set). I am not the typical point of contact for these data sets nor an expert on them, but I'll see if I can help.

If you are using Level 2 data and above (e.g. the derived physical quantities from these instruments such as wind speed), you likely don't need the DDMs for anything. So if you are after the derived physical quantities, you should be using Level 2 or 3 data.

If you are trying to use the Level 1 DDM data, these are usually for expert use. So in this case you would have to do some digging to learn more about the technical details. First thing would be to checkout our CYGNSS project page and look through the documentation, resources, journal publications, etc., to learn more about the DDMs. https://podaac.jpl.nasa.gov/CYGNSS?tab=mission-objectives&sections=about%2Bdata .

Hope this helps, please reach out with any further questions at podaac@podaac.jpl.nasa.gov .

- Dean