Arctic Sea Ice : Forum

AGW in general => Developers Corner => Topic started by: Jim Hunt on February 06, 2020, 09:38:43 AM

Title: CryoSat-2/SMOS Arctic Sea Ice Volume
Post by: Jim Hunt on February 06, 2020, 09:38:43 AM
I'm not a Python expert, so thanks are due to both Wipneus and Stefan Hendricks (https://twitter.com/sthendric/status/1222470887364091905) for their contribution to the attached source code. Thanks also to Christian for the inspiration (https://forum.arctic-sea-ice.net/index.php/topic,2969.0.html).

It converts the gridded merged CryoSat-2/SMOS Arctic sea ice volume data available from the Alfred Wegener Institute into numbers in a CSV file. Here's the data:

ftp://ftpsrv2.awi.de/sea_ice/product/cryosat2_smos/v202/nh/ (ftp://ftpsrv2.awi.de/sea_ice/product/cryosat2_smos/v202/nh/)

Here's the AWI manual:

https://spaces.awi.de/display/CS2SMOS/CryoSat-SMOS+Merged+Sea+Ice+Thickness (https://spaces.awi.de/display/CS2SMOS/CryoSat-SMOS+Merged+Sea+Ice+Thickness)

Here's the source code (rename .txt to .py):
Title: Re: CryoSat-2/SMOS Arctic Sea Ice Volume
Post by: Jim Hunt on February 06, 2020, 12:04:55 PM
Here is a rendering of the program's output created in Excel, together with the raw data in a CSV file.

Note that the most recent 2 weeks of data is "near real time". All the rest is "reanalysed".
Title: Re: CryoSat-2/SMOS Arctic Sea Ice Volume
Post by: Jim Hunt on February 12, 2020, 10:41:11 AM
Note that Stefan Hendricks has flagged up an “issue” with the CryoSat-2 NRT data:

https://spaces.awi.de/display/SIRAL/2020/02/11/CryoSat-2+-+missing+NRT+data+in+baseline-D

The NRT Level-1 data to the CryoSat-2 sea ice product is missing several orbits, mostly in the Russian Arctic as can be seen in the figure below.


(https://spaces.awi.de/download/attachments/325779690/ipf1d-nrt-datagaps-jan2020.png?version=1&modificationDate=1581414413901&api=v2)
Title: Re: CryoSat-2/SMOS Arctic Sea Ice Volume
Post by: Jim Hunt on February 19, 2020, 11:25:45 AM
Another week's data, and the "blip" is gradually disappearing. NRT data starts on January 31st in this graph:
Title: Re: CryoSat-2/SMOS Arctic Sea Ice Volume
Post by: blumenkraft on February 19, 2020, 11:45:36 AM
Jim, i think you mentioned it before, but let me ask again, what's the dotted red line? 1SD?
Title: Re: CryoSat-2/SMOS Arctic Sea Ice Volume
Post by: Jim Hunt on February 19, 2020, 06:10:27 PM
What's the dotted red line?

It's the "uncertainty" numbers from the CS2 NetCDF gridded data. You'd need to ask Stefan precisely what it represents.
Title: Re: CryoSat-2/SMOS Arctic Sea Ice Volume
Post by: blumenkraft on February 19, 2020, 06:15:15 PM
Ah, it makes sense.

Thanks, Jim! :)
Title: Re: CryoSat-2/SMOS Arctic Sea Ice Volume
Post by: Jim Hunt on August 09, 2020, 02:01:03 PM
N.B. I have discovered another "issue" with the AWI merged CryoSat-2/SMOS data, confirmed by Stefan:

https://GreatWhiteCon.info/2020/07/the-northwest-passage-in-2020/#comment-343435

Quote
It looks as though in 2019 the merged product used CS2 data in the CAA, whereas in 2020 it doesn't?