Transcript Recent & planned developments to the Met Office Global and Regional Ensemble Prediction System (MOGREPS) Richard Swinbank, Warren Tennant, Sarah Beare, Christine Johnson, Neill Bowler,

Recent & planned developments to the
Met Office Global and Regional
Ensemble Prediction System
(MOGREPS)
Richard Swinbank,
Warren Tennant, Sarah Beare, Christine Johnson, Neill Bowler, Ken Mylne, Nigel
Roberts and Adam Clayton
GIFS-TIGGE Working Group meeting #9, Sept 2011
© Crown copyright Met Office
MOGREPS –
The Met Office ensemble
• 24-member ensemble designed for short-range
forecasting
• Regional ensemble over Atlantic and Europe (NAE)
to T+54 at 06Z and 18Z
(18km grid, 70 levels)
• Global ensemble to T+72 at 00Z and 12Z
(~60 km grid, 70 levels)
NAE
• Medium-range version of MOGREPS-G:
MOGREPS-15, used for TIGGE.
• ETKF for initial condition perturbations
• Stochastic physics
• Aim to assess uncertainty in short-range, eg.:
•
•
•
•
Rapid cyclogenesis
Local details (wind etc)
Precipitation
Fog and cloud
© Crown copyright Met Office
MOGREPS has been running
since August 2005, and was made
Operational in September 2008.
Recent (2010-11) upgrades
© Crown copyright Met Office
Increased MOGREPS
resolution (2010)
• Global N144 (~90km) to N216 (~60km)
• Regional (NAE) 24km to 18km
• Both systems 38L to 70L:
© Crown copyright Met Office
Summary of 2010 MOGREPS
upgrades
- not just resolution changes
Global
Regional
PS23
(Spring)
N144L38 to N216L70
L70 physics changes
SKEB2 implementation
ETKF vertical localisation
MOGREPS-15 as Global
NAE 24km L38 to 18km L38
minimal physics changes
PS24
(Summer)
IAU - Increments added at T+0
ETKF & OPS changes
RP2 – additional BL
parameters
SKEB2 – add KE term
NAE 18km L38 to 18km L70
Physics changes for L70
© Crown copyright Met Office
Met Office hybrid implementation
(Adam Clayton, Dale Barker, Andrew Lorenc, ...)
• Basic details:
• “Alpha control variable” hybrid, with localisation in control variable space (streamfunction,
velocity potential, unbalanced pressure, humidity).
• 23 error modes from MOGREPS-G.
• Static localisation in horizontal and vertical.
• 80% climatological / 50% ensemble covariance. (Total variance inflated to maintain analysis
fit to obs.)
• Performance: ~1% improvement against obs and ECMWF analyses.
Dec uncoupled (29 days)
RMSE changes vs. obs:
• Operational implementation: July 2011.
© Crown copyright Met Office
Jun coupled (28 days)
Future upgrades
© Crown copyright Met Office
Plans for MOGREPS changes
following HPC mid-life upgrade
• Allows further improvements in resolution of operational
forecast models
• For MOGREPS we will use a two-step nesting strategy:
• Global ensemble MOGREPS-G grid ~40 km
• Regional ensemble MOGREPS-EU ~12 km
• UK convective-scale ensemble MOGREPS-UK 2.2 km
• The short-range ensemble forecasts will run four times a
day, with 12 members (1 control + 11 perturbed)
• Products calculated from pairs of lagged forecasts
• The ETKF will use 22 (later, more) perturbed members
with a 6-hour cycle
• MOGREPS-15 will continue to run twice a day
© Crown copyright Met Office
Proposed (schematic)
schedule
• Each configuration to run 3 hours after driving ensemble
to obtain freshest boundary conditions.
© Crown copyright Met Office
Proposed new
MOGREPS-EU domain
Aim to use 12km grid for MOGREPS-EU, so that MOGREPSEU control run can directly replace 12km NAE – to be retired
• Adopt new set of 70
levels to improve
resolution in lower
troposphere
• Also used for EURO4M
reanalysis project,
covering EEA countries &
Mediterranean.
• Covers Storm Surge and
ocean Atlantic Margin
model domains
• Will investigate sensitivity
to western boundary.
© Crown copyright Met Office
UKV Model Domain
for MOGREPS-UK
• Variable resolution,
2.2km in inner
domain
• Based on 1.5km
UKV model used for
convective-scale
deterministic
forecasting
• Same 70-level set as
MOGREPS-EU
© Crown copyright Met Office
Implementation schedule
• Originally planned as “big bang” implementation
at PS29 (Spring 2012), but due to delay in IBM
P7 delivery, implementation will be phased:
• PS28 (Autumn 2011)
• 4 cycles per day with current models, but using new
schedule.
• PS30 (late Spring 2012)
• Introduce MOGREPS-UK in time for Olympics
• PS31 (Autumn 2012)
• MOGREPS-EU
• Other resolution & physics changes at PS31 or PS32
© Crown copyright Met Office
Medium-range and
Seamless Forecasting
• Currently the medium-range ensemble, MOGREPS-15 is
essentially the same as MOGREPS-G but run to 15 days
using UK member-state computer time at ECMWF.
• Met Office strategy is to make forecasts consistent across
different timescales, from short-range NWP to climate
prediction.
• We are planning to bring together ensemble prediction
systems on the medium-range and monthly to seasonal
timescales, including.
• Initial condition perturbations from ETKF and, in longer term,
Ensemble Data Assimilation System;
• Coupled model to better represent ocean-atmosphere
interactions.
© Crown copyright Met Office
Schematic of possible
coupled medium-range/
monthly/ seasonal EPS
Suite 1
20 members
15 days
Suite 2
2 members
2 months
Suite 3
2 members
7 months
Suite 4
X members
Hindcast
Medium-range
products
© Crown copyright Met Office
Monthly
products
Seasonal
products
Any Questions?
© Crown copyright Met Office