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MCD43 16 day data looks like 1 day?

Posted: Thu Aug 24, 2023 3:41 pm America/New_York
by LP DAAC - dgolon
Hello,

We recently received a question from a user that we think others in the community might be wondering about too:

"Hello, I would like to ask about the two data of MCD43A3 and MCD43A4. Through my search and search, these two data are 16-day synthetic data, but when I download the website, I find that the time resolution is 1 day. How can I download these two data? What about data with a temporal resolution of 16 days? Thanks"

Re: MCD43 16 day data looks like 1 day?

Posted: Thu Aug 24, 2023 3:48 pm America/New_York
by LP DAAC - dgolon
The MCD43A3.061 (https://doi.org/10.5067/MODIS/MCD43A3.061) and MCD43A4.061 (https://doi.org/10.5067/MODIS/MCD43A4.061) datasets are available from a variety of tools including AppEEARS (https://appeears.earthdatacloud.nasa.gov/), Data Pool (https://e4ftl01.cr.usgs.gov/MOTA/), NASA's Earthdata Search (https://search.earthdata.nasa.gov/search), and USGS EarthExplorer (https://earthexplorer.usgs.gov/).

The MODIS MCD43 BRDF/Albedo products are produced daily using 16 days of acquisitions. The Julian date given in each Local Granule ID (LGID) is the 9th day of the acquisition period and values from the acquisition(s) from that day are given a higher weighted value in determining each individual pixel value from that 16 day period.

Please see the examples below for more clarity.

LGID: MCD43A4.A2023221.h11v05.061.2023230035808.hdf - This granule considered all the acquisitions from day 213 through day 228 of 2023 with emphasis on day 221.

LGID: MCD43A4.A2023222.h11v05.061.2023235012313.hdf - This granule considered all the acquisitions from day 214 through day 229 of 2023 with emphasis on day 222.

Re: MCD43 16 day data looks like 1 day?

Posted: Tue Jul 16, 2024 6:16 pm America/New_York
by joemcglinchy
hello, wanted to re-open this one. if i should start a new thread or post elsewhere, please say so and I'll do that.

I am searching the LPCLOUD STAC api for the MCD43A4 products. For all products associated with March 17, 2024 and onward, I am seeing only 7 days related to the observations going into a single granule, evidenced by `start_datetime` and `end_datetime`. I included an example at the end of the message.

Despite what the metadata says, can we still treat these files as best-of 16 day observations?

{'type': 'Feature',
'stac_version': '1.0.0',
'id': 'MCD43A4.A2024071.h25v07.061.2024085192330',
'properties': {'datetime': '2024-03-11T00:00:00Z',
'start_datetime': '2024-03-11T00:00:00.000Z',
'end_datetime': '2024-03-18T23:59:59.999Z'},
'geometry': {'type': 'Polygon',
'coordinates': [[[70.8157, 9.9696],
[81.2533, 9.9477],
[85.1463, 19.9996],
[74.2034, 20.021],
[70.8157, 9.9696]]]},
'links': [{'rel': 'self',
'href': 'https://cmr.earthdata.nasa.gov/stac/LPCLOUD/collections/MCD43A4.v061/items/MCD43A4.A2024071.h25v07.061.2024085192330'},
{'rel': 'parent',
'href': 'https://cmr.earthdata.nasa.gov/stac/LPCLOUD/collections/MCD43A4.v061'},
{'rel': 'collection',
'href': 'https://cmr.earthdata.nasa.gov/stac/LPCLOUD/collections/MCD43A4.v061'},
{'rel': 'root',
'href': 'https://cmr.earthdata.nasa.gov/stac/LPCLOUD',
'type': 'application/json',
'title': 'LPCLOUD'},
{'rel': 'provider', 'href': 'https://cmr.earthdata.nasa.gov/stac/LPCLOUD'},
{'rel': 'via',
'href': 'https://cmr.earthdata.nasa.gov/search/concepts/G2909970317-LPCLOUD.json'},
{'rel': 'via',
'href': 'https://cmr.earthdata.nasa.gov/search/concepts/G2909970317-LPCLOUD.umm_json'}],
'assets': {'data': {'href': 'https://data.lpdaac.earthdatacloud.nasa.gov/lp-prod-protected/MCD43A4.061/MCD43A4.A2024071.h25v07.061.2024085192330/MCD43A4.A2024071.h25v07.061.2024085192330.hdf',
'title': 'Download MCD43A4.A2024071.h25v07.061.2024085192330.hdf'},
'browse': {'href': 'https://data.lpdaac.earthdatacloud.nasa.gov/lp-prod-public/MCD43A4.061/MCD43A4.A2024071.h25v07.061.2024085192330/BROWSE.MCD43A4.A2024071.h25v07.061.2024085152807.1.jpg',
'type': 'image/jpeg',
'title': 'Download BROWSE.MCD43A4.A2024071.h25v07.061.2024085152807.1.jpg'},
'metadata': {'href': 'https://cmr.earthdata.nasa.gov/search/concepts/G2909970317-LPCLOUD.xml',
'type': 'application/xml'}},
'bbox': [70.8157, 9.9477, 85.1463, 20.094915],
'stac_extensions': [],
'collection': 'MCD43A4.v061'}