Unified Model Developments 2002

1 10/2002 © Crown copyright

Unified Model Developments 2002

Clive Wilson

NWP

Met Office


Outline

Configurations & Users

Global and UK Mesoscale Changes

Regional European Model

New supercomputer

Plans


Operational Versions & External Users

Global 38 levels, N216= 432x325 (~60km)

UK Mesoscale 38 levels, 0.11 deg (12km)

Stratospheric 42 levels (~1.3km @ 100-1hpa), N48=96x73 (~300km)

Crisis models (LAMS) Middle East, Former Yugoslavia,SW Asia

External CGAM UK, ICM Warsaw, Thai Met Service, New Zealand, DNMI


Changes

Global G26 16 Oct 3dvar upgrade

Increase Observation errors for AMVs

Revise thinning of ATOVS to give preference to microwave-clear over IR-clear

Use of fractional sea-ice in ATOVS processing

G27 7 August 2002 New Dynamics and HadAM4

G28 1 Oct Introduce NOAA17

UK Mesoscale G27 7 August 2002 New Dynamics


New Dynamics ( Hadam4 )PhysicsSemi -Lagrangian advection(With monotone advection of potentialtemperature)

* Edwards-Slingo Radiation

Semi-implicit time integration * Mixed phase precipitation Including iterative freezing level

Horizontal staggering - C grid * New Boundary Layer + 38LVertical Staggering - Charney Philips * MOSES IINon-hydrostatic formulation * Effective area cloud fraction Vertical

gradient cloud fractionNew physics compared to current

operationalLateral boundaries (8 points -5 outerglobal)

Orography -smoothed (Raymond =1) Lateral boundaries 6 global, 10 point

linear transition to mesoscaleConvection CAPE closure, 30 min timescale Momentum transportNew Gravity wave dragVisibility in snow correction

*Already operational in Mesoscale Model


Expected benefits of New Dynamics

Non-hydrostatic capability – ability to increase resolution in UK area.

Improved stability and accuracy - less noise in forecasts

Improved physics for global model - improved coupling to dynamics.

Unify physics between global and UK area - Better boundary conditions.

Better coupling with 3D-Var which was designed around new grid.


New Dynamics levels

Dec 2001- Jan 2002

-10

-5

0

5

10

15

Mar - Apr 2001

-10

-5

0

5

10

15

Jun-Jul 2001

-10

-5

0

5

10

15

Sep-Oct 2001

-10

-5

0

5

10

15

MS

LP

24

MS

LP

48

MS

LP

72

MS

LP

96

MS

LP

120

H50024

H50048

H50072

W25024

W85024

W85048

W85072

W25024

MS

LP

24

MS

LP

48

MS

LP

72

MS

LP

96

MS

LP

120

H50024

H50048

H50072

W25024

Bars show the %change in RMSE (NDHadAM4 - OP/OP) for the components, which make up the NWP index. Verification is against observations. Blue signifies Northern Hemisphere, red the Tropics and Green is the Southern Hemisphere. A negative value implies NDHadAM4 is an improvement over OP.


Typhoon Phanfone

18 August 2002


Screen temperature Shadow suite (16/1-4/2), all stations

mean

rms

OPND

forecast range

0 12 24 36

forecast range


10-metre wind Shadow suite (16/1-4/2), all UK stations

mean

speed

rms

vector

OPND

0 12 24 36


Relative Humidity Shadow suite (16/1-4/2), all stations

mean

rms

OPND

forecast range

0 12 24 36


Visibility Shadow suite (6/12-4/2), all stations


Rainfall (skill) Shadow suite (6/12-28/1)

v Nimrod 6-hourly accumulations


Rainfall (bias) Shadow suite (6/12-28/1)

v Nimrod 6-hourly accumulations


Strong summer convection


French Storm Vt 12Z

27/12/1999

T+0

T+72

OP ND


Danish Storm Vt 12Z

03/12/1999

T+0

T+24

OP ND


Reduced Noise in New Dynamics


New Dynamics Summary

Reduced NH RMSE in summer and at early FC ranges in winter

Deeper extratropical cyclones

Reduced temperature biases

Improved stratospheric circulation statistics (eddy temperature fluxes)

Reduced noise in ND forecasts.

Improved radiative balance - OLR

Tropical upper level wind RMSE too large (~6-10%)

SH T+24 wind RMSE too large (vs analysis) - corrections ready

Grid point storms at N216.

Tuning of orographic and BL drag and diffusion still required.

Low cloud in UK mesoscale

Poor initial precipitation in UK Mes

Benefits Problems


New Regional European model

Opportunity to reorganise Operational suite

– New dynamics model formulation (August 2002) Better Global performance but double cost

2X number of processors to keep to delivery time

Mesoscale ~same as current

—relatively more efficient than global

– Remove duplication of Global Preliminary/Main runs


Resources

Make full use of operational time & processors

Processors

– global 288, UKmes 108 factor of 2.8

Release duplicate Prelim/main

– analysis +2 day forecast (=40min)

60min slot (=20 min gap + “duplicate time”)

~5X UKmes cost


Proposed Domain

Current UK mesoscale

New Euro Mes 20km resolution

548

320

Current Operational Schedule

Ocean, wave, surge+4:50

00/12

+1:502 Days Prelim Run

Boundary Forcing

+2:40

2 Days

+3:00

Main Run

6 Days

00/12

2 Days

2 Days+7:50 Prelim Run

Proposed Operational Schedule

Boundary Forcing

2 Days

+2:40

Ocean, wave, surge+4:50

2 Days Main Run part 1

00/12

+1:50

Continued Main Run

Days 2-6+3:40

00/12

+3:002 Days Euro Run


Estimated Skill score change for extended "Preliminary" Global model. Period =200012-200111

-0.04

-0.03

-0.02

-0.01

0

0.01

0.02

0.03

0.04

0.05

T+24PMSL

NH

T+48PMSL

NH

T+72PMSL

NH

T+96PMSL

NH

T+120PMSLNH

T+24H500NH

T+48H500NH

T+72H500NH

T+24W250

NH

T+24W850Trop

T+48W850Trop

T+72W850Trop

T+24W250Trop

T+24PMSL

SH

T+48PMSL

SH

T+72PMSL

SH

T+96PMSL

SH

T+120PMSLSH

T+24H500SH

T+48H500SH

T+72H500SH

T+24W250

SH

Parameter

unweighted skill diff Wtd Skill diff

Estimated Global worsening

250hPa winds

estimated


Estimated effect on Global Index

Index Impact (%)

-1.2

-1

-0.8

-0.6

-0.4

-0.2

0

0.2Oct

-00

Nov-0

0

Dec-0

0

Jan-

01

Feb-0

1

Mar

-01

Apr-0

1

May

-01

Jun-

01

Jul-0

1

Aug-0

1

Sep-0

1

Oct-0

1

Nov-0

1

Dec-0

1

Jan-

02

Feb-0

2

Mar

-02

Apr-0

2

May

-02

Jun-

02

Mea

n

Index Impact (%)


Timetable 5 November - Merge Prelim/Main model +digital filter

intitialisation instead of incremental analysis update

– but leave split of run until next year

12 Nov -Forecast only European Model introduced

Post November -products and downstream use developed

14 Jan - basic data assimilation

25 March- model & DA upgrade

June 03 - Declare Euromodel operational (high risk -Exeter transition)


New supercomputer need Improve NWP systems:

Satellite data volumes

New Dynamics

4D-VAR

Higher resolutions

Very fine resolution mesoscale (~2km)

European Mesoscale model

Short range Ensembles

Operational Suite creaking at the seams


What are we getting?

Initially - NEC SX-6

– 30 nodes

– Each node has 8 CPUs sharing 64Gb of memory

– Each CPU is equivalent to approx 30 T3E CPUs

– Overall performance:

» 6x T3E’s for “performance work”

» > 6x T3E’s for “throughput work”


And in the future

In 2005 - joined by SX-6 successor:

– 15 nodes

– Each CPU twice as powerful

– Overall performance

» 12.5x T3Es for “performance work”

» >12.5x T3Es for “throughput work”


Benchmark Results (N324L50)

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

10.00

11.00

12.00

13.00

14.00

15.00

0.0% 10.0% 20.0% 30.0% 40.0% 50.0% 60.0% 70.0% 80.0% 90.0% 100.0%

% System

Facto

r

Performance Throughput


Met Office Networks

FC

Sw

itch

Mirrored filesystemsUser

filesystems

FibreChannel

Fro

nt

En

d12xIA

64

Fro

nt

En

d12xIA

64

Gigabit Etherne

t

The BitsN

OD

E(8

C

PU

s)

NO

DE

(8

CP

Us)

NO

DE

(8

CP

Us)

NO

DE

(8

CP

Us)

NO

DE

(8

CP

Us)

NO

DE

(8

CP

Us)

NO

DE

(8

CP

Us)

NO

DE

(8

CP

Us)

NO

DE

(8

CP

Us)

NO

DE

(8

CP

Us)

NO

DE

(8

CP

Us)

NO

DE

(8

CP

Us)

NO

DE

(8

CP

Us)

NO

DE

(8

CP

Us)

NO

DE

(8

CP

Us)

IXS(Interconne

ct)

IXS

Timetable Installation

Sep 02Oct 02Nov 02Dec 02Jan 03Feb 03Mar 03Apr 03May 03Jun 03Jul 03Aug 03Sep 03Oct 03Nov 03Dec 03

Date Bracknell SX-6

1 node syste

m

Upgrade:4 nodes

Front end

Move to Exeter

T3E-A

Move to Exeter

02/09-06/10

T3E-B

Move to Exeter

17/06-22/07

ExeterSX-6(B)

15 node system

ExeterSX-6(A)

15 node system

Acceptance tests


Plans 2002- 2003 November UK Mes DA-improved covariances

December Global model & DA

January New Dynamics in Stratospheric model

Data assimilation in Euro model

Feb-March -Global, UK mes & Euro model+DA upgrades

Transition to Exeter

– Moratorium May 03 - October 03

Future Plans 4dVar

Practicable global synoptic scale ready for test on new computer end 03

Inclusion physical processes 04

operational early(?) 2004

Increased resolution » 40km , 50L Global; 10km , 50L Euro mesoscale

Physics —new gravity wave drag

—new convection

—new cloud (prognostic cloud and condensate)

Unified Model Developments 2002

Documents

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