Driving UM-SCM with Driving UM-SCM with reanalysis / model datareanalysis / model data

Vaughan BarrasVaughan BarrasACCESSACCESS

Model Development GroupModel Development Group

Dynamically constrained simulationsDynamically constrained simulations

Previous experience constraining GCMs dynamically with reanalyses, allowing other model components to evolve 18O in hydrological cycle eg: Melbourne Uni Network

of Isotopes in Precipitation 3rd IOP

(Jun 11, 2005)

• See also:Noone (2006) (WGNE Rep. 36; WMO/TD-No.

1347)

Yoshimura et al., 2008 (JGR, 113, D19108)

Barras and Simmonds, (submitted to JGR)

Use in SCMs?Use in SCMs?…yes…provided it is set up carefully and SCM used appropriately.

• Idealised cases (equilibrium, constant forcings)Idealised cases (equilibrium, constant forcings)• Targeted studies (Intercomparisons)Targeted studies (Intercomparisons)

• Intensive Observational Campaigns (IOPs)Intensive Observational Campaigns (IOPs)• TWP-ICE, TOGA-COARE, GABLS, DYCOMS, RICO, Cabauw,…TWP-ICE, TOGA-COARE, GABLS, DYCOMS, RICO, Cabauw,…

• Alternative namelist generation?Alternative namelist generation?

• NWP forcingsNWP forcings• Useful - depending on what is under investigationUseful - depending on what is under investigation• Complicated setup…Complicated setup…

genesisgenesis

Software to create SCM namelists at a user-defined location from reanalyses / model input.

Uses:Uses:• Testing of parameterisations under a range of scenariosTesting of parameterisations under a range of scenarios

• IOPs can be subjective in the conditions they representIOPs can be subjective in the conditions they represent

• Based on approximate ‘real-world’ conditions (reanalyses)Based on approximate ‘real-world’ conditions (reanalyses)

• Extract model conditions for detailed testingExtract model conditions for detailed testing

• Efficiency enables creation of ensemble namelistsEfficiency enables creation of ensemble namelists• Variable initial conditions, major forcing fields.Variable initial conditions, major forcing fields.

how it workshow it works• Download global NetCDF fields of pDownload global NetCDF fields of pmslmsl, , , U, V, T, q , U, V, T, q

for desired periodfor desired period• ERA40ERA40• JRA25 (q > level 12 = 0.0)JRA25 (q > level 12 = 0.0)• NCEP (genesis converts RH to q)NCEP (genesis converts RH to q)• UM

• dumps from STASH (sub-periods of longer runs)• Use ‘Trans’ option in xconv to interpolate to grid.

• User specifies lat / lonUser specifies lat / lon• Define ‘files.inp’ and ‘dates.dat’ filesDefine ‘files.inp’ and ‘dates.dat’ files

• Simple list of input file names and dates matching inputsSimple list of input file names and dates matching inputs

• Command line executionCommand line execution• Can be scriptedCan be scripted

genesis --helpgenesis --helpgale/vjb> genesis gale/vjb> genesis

Usage: genesisUsage: genesis genesis [options]genesis [options] -d verbose, debug mode-d verbose, debug mode -h help-h help -t no. of time increments (def=150)-t no. of time increments (def=150) -l no. of levels of input data (def=20)-l no. of levels of input data (def=20) -x no. of longitudes (def=29)-x no. of longitudes (def=29) -y no. of latitudes (def=17)-y no. of latitudes (def=17) -X user defined longitude (eg: 243.7)-X user defined longitude (eg: 243.7) -Y user defined latitude (eg: 65.0)-Y user defined latitude (eg: 65.0) -D use date file (def = false)-D use date file (def = false) -O use offset file (def = false)-O use offset file (def = false) -E ERA40 data (def = false)-E ERA40 data (def = false) -J JRA data (def = false)-J JRA data (def = false) -N NCEP data (def = false)-N NCEP data (def = false) -U UM data (def = false)-U UM data (def = false) You also need a few files in the run directory for this to work.You also need a few files in the run directory for this to work. a) files.inp - a file listing the *.nc file names in order: ps,z,u,v,t,qa) files.inp - a file listing the *.nc file names in order: ps,z,u,v,t,q b) offset.dat (optional) - list of offset parameters fromb) offset.dat (optional) - list of offset parameters from ncdump hdr [scale, add]ncdump hdr [scale, add] - if geopotential needs converting only (m2/s2 >> m)- if geopotential needs converting only (m2/s2 >> m) then use -O with offset file set to 1 0 for each.then use -O with offset file set to 1 0 for each. c) dates.dat (optional) - a list of dates/times corresponding to data records.c) dates.dat (optional) - a list of dates/times corresponding to data records. [generate using datetraj - yyyymmdd hhhh][generate using datetraj - yyyymmdd hhhh]

detailsdetails• Read NetCDF fieldsRead NetCDF fields

• Finds nearest neighbour grid points for interpolationFinds nearest neighbour grid points for interpolation

• Calculates advective tendencies (T, q)Calculates advective tendencies (T, q)

• Linear interpolation of fields (horizontally)Linear interpolation of fields (horizontally)• Could incorporate other interpolation methods if desiredCould incorporate other interpolation methods if desired

• Derivation of geostrophic wind profilesDerivation of geostrophic wind profiles

• Assign dates / times to recordsAssign dates / times to records

• Intermediate output field (*.scm)Intermediate output field (*.scm)• Initial profiles (P_IN, UI, VI, QI, THETA)Initial profiles (P_IN, UI, VI, QI, THETA)• Increments (U_INC, V_INC, T_INC, Q_STAR)Increments (U_INC, V_INC, T_INC, Q_STAR)

• Output ‘namelist.scm’Output ‘namelist.scm’• Still needs to be checked before running!

Example – CASES 99Example – CASES 99

U

V

T

q

NWP forcing profiles compared with hi-res soundings from CASES 99

Example – CASES 99Example – CASES 99

U*

Tsfc

ERA40 forced UM-SCM runs

= 6hr

= 48hr

however…however…

Still requires user to set up cases carefully.Still requires user to set up cases carefully.

• SCM6.3 has constant SCM6.3 has constant ŪŪgg

• Restricted to short runs where synoptic circulation isn’t rapidly Restricted to short runs where synoptic circulation isn’t rapidly changing (midlats can be a problem in this regard, tropics ok)changing (midlats can be a problem in this regard, tropics ok)

• Variable setting in SCM7.1, enables longer simulationsVariable setting in SCM7.1, enables longer simulations

• No inclusion of ‘w’No inclusion of ‘w’• SCMs sensitive to these settings, best if user defined / derived SCMs sensitive to these settings, best if user defined / derived

by model continuityby model continuity

• Not comparable to observations, but…Not comparable to observations, but…• Genesis can provide framework for parameterisation sensitivity Genesis can provide framework for parameterisation sensitivity

studies, not restricted by IOP location.studies, not restricted by IOP location.• Enables targeting of problem regions / conditionsEnables targeting of problem regions / conditions

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