wiki:ticket/370/TicketDetails

Version 5 (modified by Jin Lee, 2 years ago) (diff)

--

Assess possible degradation of TC forecasts by ACCESS-G caused by not assimilating some observation types

Additional observation types

Following table shows a comparison of observations which are currently used operationally in ACCESS-G3 and those used in OSNN,

???? table incomplete - see what UKMO are using ????

Obstype Usage in ACCESS-G3 Usage in OSNN Comment
METAR used used
Megha-Tropiques/SAPHIR not used used
Meteosat-? not used used

Experimental set-up

For each TC case we will use a control and a test. The control will have only the observation types used operationally whereas the test will assimilate additional observation types that we currently do not assimilation but are used by UKMO.

We will mainly assess the difference in track forecasts between control and test. However a question arises as to how robust the difference in track forecasts is. It's possible that the difference arose because of the inherent chaotic nature of the data assimilation system and the forecast model. To allow us to approximately the effect of this randomness we will also create an initial condition by adding global, random perturbations to the control.

Trial periods

Jim's list of TC's that were declared around Western and Easter Indian Ocean between late 2017 and early 2018,

TC Start date End date Lifetime
(days)
Number
of
00Z/12Z
runs
Min
CP
(hPa)
Comments
CEMPAKA 2017112712 2017112900 2.0 4 997SouthIndianOcean
DAHLIA 2017112912 2017120212 3.5 7 985SouthIndianOcean
OCKHI 2017113012 2017120512 5.5 11 976NorthIndianOcean
KAI-TAK 2017121400 2017122112 8.0 16 996NorthWestPacific
TEMBIN 2017122100 2017122512 5.0 10 975NorthWestPacific
HILDA 2017122712 2017122918 1.0 2 985SouthIndianOcean
BOLAVEN 2018010300 2018010312 1.0 2 1002NorthWestPacific
IRVING 2018010600 2018010912 4.0 8 964SouthIndianOcean
JOYCE 2018011100 2018011212 2.0 4 982SouthIndianOcean
CEBILE 2018012800 2018020412 8.0 16 944SouthIndianOcean
FEHI 2018012900 2018013000 1.5 3 985SouthPacific
GITA 2018020912 2018021912 10.5 21 928SouthPacific
SANBA 2018021112 2018021312 2.5 5 1002NorthWestPacific
KELVIN 2018021712 2018021900 2.0 4 975SouthIndianOcean

The following is a list of TC's used in this experiment and the trial periods,

TC First cycle of trial last cycle of trial lon/lat when fist declared Category Comments
KAI-TAK 2017120400 2017122318
TEMBIN 2017121100 2017122518 straight track
HILDA 2017121700 2017122318
BOLAVEN 2017122400 2018010318
IRVING 2017122700 2018010618 Cat 1
JOYCE 2018010100 2018011318 Cat 1
CEBILE 2018011800 2018020818
FEHI 2018011900 2018013018
GITA 2018013100 2018022218 Cat 4
SANBA 20180020100 201802118 Cat 4

Configuration

4DVar

  • non-hybrid 4DVar

UM

  • PC2 cloud scheme
  • ????

Resources

  • JTWC bogus central pressure observations are available from Dec, 2017

Things to do

  • For Ops_ExtractAndProcess tasks work out how to read UKMO obstore files
    • Do we use exclusively obstores from UKMO - both for control and test?
  • Need initial varstats files

Attachments (1)