Hello forum,
I found a strange error, where some acquisitions of a certain Sentinel 1A scene in orbit 69 are smaller on some dates than on others.
The scene S1A_IW_SLC__1SDV_20231116T100430_20231116T100457_051241_062E6C_E617
for example has the normal size as expected (see green bounding box on the right side).
But the scene S1A_IW_SLC__1SDV_20231128T100430_20231128T100449_051416_063479_D4D5
misses a pretty large stripe on its northern end (green bounding box on the left side). I marked the missing part in red.
This behaviour happens in irregular intervals and I found acquisitions of other dates, where exactly the same part is missing. For the last year the scenes with the missing part are:
S1A_IW_SLC__1SDV_20230812T100429_20230812T100448_049841_05FE86_B1A0
S1A_IW_SLC__1SDV_20230905T100430_20230905T100450_050191_060A81_D64A
S1A_IW_SLC__1SDV_20230917T100431_20230917T100450_050366_06106D_9A3F
S1A_IW_SLC__1SDV_20230929T100431_20230929T100451_050541_06166A_5C06
S1A_IW_SLC__1SDV_20231023T100431_20231023T100451_050891_062262_A1B5
S1A_IW_SLC__1SDV_20231128T100430_20231128T100449_051416_063479_D4D5
S1A_IW_SLC__1SDV_20231210T100430_20231210T100449_051591_063A8B_69B3
S1A_IW_SLC__1SDV_20231222T100429_20231222T100448_051766_0640A4_3F15
S1A_IW_SLC__1SDV_20240103T100428_20240103T100448_051941_06469E_45CB
Has somebody of you seen this error before or has any explanation for it?
I would be happy about any hints.
Thank you!
Maybe this is also a helpful visualisation of the problem. When I am using the Alaska Satellite Facility’s search tool it looks like this. Red is the scene with the missing part and blue the normal one:
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Is there some ground-coverage missing, or is this just a case of reduced overlap?
1st you could check whether the “strange” acquisition were acquired according to the acquisition plans:
…or if there was an anomaly that shortened the planned data take:
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Hello mengdahl,
there is some ground coverage missing. But you are right, according to the acquisition plan kmz files I can see, that there was no acquisition planned on these days. So this is no error. Thank you very much for the quick answer and for the hint with the acquisition segments!
Maybe here a small picture for everybody to understand…
On the days where the scene was a bit smaller, the planned acquisition just stopped in the scene that I was looking at (yellow polygon). On the other days there was a larger area covered (red polygon).
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That is normal. The S-1 constellation is operating at 1/2 nominal capacity until S-1C has been launched and commissioned.
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Hi! I faced a similar problem. I loading Sentinel-1 SLC data from Copernicus. Copernicus displays the data on the territory I need, but after I open the file in SNA
P, neither iw1 nor iw 2 covers my area. There is no iw3 at all.
I downloaded several archives and the situation is the same everywhere.
Hi @VadimNAU2024,
A similar problem has been posted here: Changes to Copernicus Sentinels data access - Copernicus Data Space Ecosystem - #16 by Unmanaged0292 and JIRA ticket SNAP-3578 has been created to track the issue.
Please try to open the unzipped product.
