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Aqua-CERES Level 2 data
Posted: Wed Jun 03, 2020 3:55 pm America/New_York
I have two questions about the data named in the fashion "CER_SSF_Aqua-FM3-MODIS_Edition4A_404405.2018060100".
1. How to get the FOV index? The data is compiled in a large vector, how to identify their FOV position in each cross-track?
2. Has the data been done for the view angle correction? If yes, do you have any reference about it?
Re: Aqua-CERES Level 2 data
Posted: Wed Jun 03, 2020 4:11 pm America/New_York
I’m not entirely clear in what the you are requesting, but I will provide what I think you are asking.
1. Each footprint has a Scan sample number that describes the order of the FOV in each packet. There are 660 samples in each packet, but since the majority are not Earth viewing they are not included on the SSF. Since a packet is defined as starting internally on one side sweeping across and then returning to the starting side, there will be Earth viewing footprints around sample 80 - 255 and again at 410 - 585 . With 255 and 410 and 80 and 585 being more closely aligned.
The view zenith angle, CERES viewing zenith at surface, is included on the data which would also provide their position in the swath. This number does not have a sign, so will not provide information on which side of the path it is.
2. There is no view zenith correction to the data. The footprints increase in size with view zenith. Also, the order of the footprint is based on along-track angle. At the edges of the footprint, the packet order can be intermixed.