Query about GEDI time quantum

[deace]

Is there exists GEDI campaign table(equivalent to ICESAT-1 which about 91 days for one campaign) so that I could know how to choose time quantum so that it could covered global forest/terrain .If not ,any time quantum for suggestions. Thanks so much for any
information!

[LP DAAC - jwilson]

Hi @deace ,
We have forwarded your question to our subject matter expert for further assistance.

[LP DAAC - afriesz]

@deace ,

It is not clear to me what you’re asking for exactly. GEDI continuously collects lidar samples globally from the International Space Station. If you’re trying to find and access data that spatially and temporally intersect with you research parameters, I would recommend using Earthdata Search (https://search.earthdata.nasa.gov/search) to do this. From there, you can specify an area of interest, a temporal range, and the specific GEDI data product you wish to query against. If this is not what you are looking for, please supply us with some more details regarding what you are accomplish. I’m not familiar with the ICESAT-1 campaign table. Would you be able to provide a link to that resource?

[deace]

equivalent to revisit time

[LP DAAC - afriesz]

@deace,

Would you be able to share a link to the ICESAT-1 campaign table? I'm curious what it looks like. I don't think there is a 'table' containing the revisit intervals. Is there any reason why Earthdata Search doesn't at least get you partially there? You can search for you area of interest using the Earthdata Search interface to generate a list of scenes through time that you can download. You could then use the python scripts here: https://git.earthdata.nasa.gov/projects/LPDUR/repos/gedi-v2-tutorials/browse to identify the shots you are interested in and process them.

[deace]

LP DAAC - afriesz wrote:
> @deace,
>
> Would you be able to share a link to the ICESAT-1 campaign table? I'm
> curious what it looks like. I don't think there is a 'table' containing the
> revisit intervals. Is there any reason why Earthdata Search doesn't at
> least get you partially there? You can search for you area of interest
> using the Earthdata Search interface to generate a list of scenes through
> time that you can download. You could then use the python scripts here:
> [url]https://git.earthdata.nasa.gov/projects/LPDUR/repos/gedi-v2-tutorials/browse[/url]
> to identify the shots you are interested in and process them.

with 33–56-day campaigns, roughly each four months the ICESat/GLAS collected full-waveform records with near global coverage.So how can i decide the temporal settings when i want nearly global coverage GEDI data?(one month,6 months or one year ?for example)because when i download gedi data within the single month,i find large rhombus-shape gap bewteen the satellite tracks,thats means many area within my ROI lack of those observations .
looking forward to your Suggestions.
THANKS!

[LP DAAC - afriesz]

@deace ,

The areas of no observations, or the ‘rhombus-shape’, you are seeing is a result of a couple things (probably more, but I’ll mention the things I know about). The first being the ISS orbit and the second being the altitude of the ISS. The ISS has a precessing orbit and not a polar orbiting one. This video has a pretty good depiction of the ISS orbit: https://www.youtube.com/watch?v=wxgrxvAKpTo. The precessing orbit results in continuous measurements between ~52°N and ~52°S latitude with revisits around 1-5 days depending on latitude. This causes the initial ‘rhombus-shape’ you see. In the case of GEDI, the size of the rhombuses has been influenced by the actual altitude the ISS and the expected altitude of the ISS when the GEDI instrument specification were developed. Fairly early in the GEDI mission the ISS increased its altitude which resulted in more overlap of GEDI observations and subsequently less spatial coverage.