Opened 4 weeks ago

Last modified 6 days ago

#2731 assigned help

Another data request

Reported by: shakka Owned by: willie
Priority: normal Component: Data
Keywords: ECMWF, grib, SST, sea ice, ERA-Interim Cc:
Platform: Monsoon2 UM Version: 11.1


Hi Willie,

I'm afraid I need to ask you for more data. I've been advised that I should use ERA-Interim at 6-hourly resolution for my hindcast runs. Am I right in thinking that these do not include sea ice and SST fields? Are you able to supply me with sea ice and SSTs separately?

As before, I would need ten years' data from 2008-2017, including a month's spin-up, so 20071201_00 to 20171231_18.

If it helps reduce the amount of data you need to download, I know that James Pope has daily ECMWF data for some of the period I require:

i.e. the period 20071201_00 to 20161231_00, at 24 hourly intervals

and that Andrew Orr has 6-hourly data, including sea ice and SSTs, from 20140701_00 to 20141031_18.

I could easily copy this from their workspaces to save time.

I know this is going to be a huge amount of data so I'm happy to do it in batches if this helps.

Best wishes,

Change History (8)

comment:1 Changed 4 weeks ago by willie

Hi Ella,

I've started to get the first year's worth. These will be ERA-I start dumps including SST and sea-ice fields. They work out at 55MB each, so the full ten years will be about 785 GB and will comprise 14,610 files.


comment:2 Changed 4 weeks ago by shakka

Thank you so much Willie, you're a hero.

comment:3 Changed 3 weeks ago by willie

Hi Ella,

The first years worth are now in /projects/nexcs-n02/frmy/data_xfer. Please copy them to you own work space as soon as possible.

Let me know how you get on and I will generate and transfer the rest.


comment:4 Changed 3 weeks ago by shakka

Hi Willie,

Thank you for this - I have now copied all of the first year's data over.

Just to confirm: because you have kindly provided me with ECMWF sea ice and SSTs, I shouldn't need to reconfigure the glm to update this from ancillaries, correct?
i.e. within glm_um → namelist → Reconfiguration and Ancillary Control → Configure ancils and intialise dump fields I should only have to add in 0,32 Sea ice depth and not reconfigure SST or sea ice fraction at all ?


comment:5 Changed 3 weeks ago by willie

Hi Ella,

In principle, yes but in this case it might be no. The problem is that the original ancillary file n768/seaice/hadisst_6190/v1/qrclim.seaice has three fields,

  • Fraction of sea ice in sea
  • ice edge in the ancillary file only (sic)
  • sea ice depth

so originally it would have been updating all three from the ancillary file. But you are only replacing one. Without looking at the code, it seems to me that you will need the other two fields to be in the start dump too, before you can switch the ancillary off. I'll ask an expert tomorrow.


comment:6 Changed 3 weeks ago by shakka

Hi Willie,

Thanks for this, I look forward to hearing back tomorrow.


comment:7 Changed 13 days ago by willie

  • Owner changed from um_support to willie
  • Status changed from new to assigned

Hi Ella,

Sorry for the delay.

You are currently configuring the fraction of sea ice and the sea ice depth from the ancillary file in u-be285. But you want to run with regular start dumps that contain fraction of sea ice, but not the ice depth, so the ancillary file is not really necessary provided the ice depth can be calculated.

This can be done on the reconfig → ancil options page: select the the AMIP II method of updating SST and sea ice. This will generate the sea ice depth from the ice fraction in the dump.


comment:8 Changed 6 days ago by shakka

Hi Willie,

Thanks for this (and apologies for late reply - I've been away). I have selected the AMIP 2 method of calculating sea ice depth. Do I still need to reconfigure the sea ice depth as I have previously done for other fields from the GRIB file by adding a section in glm_um> namelist> reconfiguration and ancillary control> configure ancils and initialise dump fields? When I try to run without I get an error immediately.


Note: See TracTickets for help on using tickets.