# ⚠️ Inconsistent ocean and sea ice in final 7.5yr of 0.1° IAF cycle 4

**URL:** <https://forum.access-hive.org.au/t/inconsistent-ocean-and-sea-ice-in-final-7-5yr-of-0-1-iaf-cycle-4/1492>\
**Category:** COSIMA\
**Tags:** data, access-om2, bug\
**Created:** [10 October 2023 06:36 UTC](https://forum.access-hive.org.au/t/inconsistent-ocean-and-sea-ice-in-final-7-5yr-of-0-1-iaf-cycle-4/1492 "2023-10-10T06:36:09Z")\
**Posts on this page:** 1\
**Showing post:** 1

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**Author:** ![aekiss](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.access-hive.org.au/aekiss/32/46_2.png) [@aekiss](https://forum.access-hive.org.au/u/aekiss)\
**Post date:** [10 October 2023 06:36 UTC](https://forum.access-hive.org.au/t/inconsistent-ocean-and-sea-ice-in-final-7-5yr-of-0-1-iaf-cycle-4/1492/1 "2023-10-10T06:36:09Z")

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Hi all,

Apologies - I’ve recently discovered the ocean and sea ice data are inconsistent in `01deg_jra55v140_iaf_cycle4` from 2011-07-01 (output962) to the end of the cycle (2018-12-31).

How this occurred:

- Last year I accidentally deleted sea ice data from April 2002 to the end of 2018 (apart from 6-hourly ice area from 2014-2016 inclusive) during post-processing prior to sharing the data.
- I re-generated the deleted sea ice data in [01deg\_jra55v140\_iaf\_cycle4\_rerun\_from\_2002](https://github.com/COSIMA/01deg_jra55_iaf/tree/01deg_jra55v140_iaf_cycle4_rerun_from_2002) (which also added daily aicen, vicen and 3-hourly uvel, vvel, divu, shear for 2016).
- This re-generated data (including the extra 2016 outputs) was added to the `01deg_jra55v140_iaf_cycle4` output directory on cj50.

The re-run `01deg_jra55v140_iaf_cycle4_rerun_from_2002` was identical to the original `01deg_jra55v140_iaf_cycle4` for about half the run (from April 2002 until the run starting 2011-07-01). The re-run ocean and sea ice then started to deviate from the original, for reasons I’m yet to figure out (we’ve seen this [once before](https://github.com/COSIMA/access-om2/issues/266)). By the end of 2018 there are visually obvious differences in eddy locations between the runs (thanks to chaos).

Consequently

- all non-6-hourly sea ice data in `01deg_jra55v140_iaf_cycle4` is inconsistent with the ocean data from 2011-07-01 onwards
- the 6-hourly ice area (2014-2016 inclusive) is inconsistent with the other sea ice variables, but consistent with the ocean

I’ll do some experiments to see whether the reproducibility failure occurred in the original run or the re-run. If the latter, it may be possible to correct it.

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_[View the full topic](https://forum.access-hive.org.au/t/inconsistent-ocean-and-sea-ice-in-final-7-5yr-of-0-1-iaf-cycle-4/1492)._