Transcript Weather Prediction and the use of weather data The European Centre for

Weather Prediction
and the use of weather data
The European Centre for
Medium-Range Weather Forecasts
ECMWF
David Burridge with help from
A. Simmons, G. Kelly, J-N Thepaut,
D. Marbouty, A. Thorpe, A. Lorenc, T. Palmer
……
DB-1
International Session 2003
ECMWF
Annual means of the forecast range at which the
anomaly correlation of 500 hPa forecasts first reaches
The 60%, 655, 70%, 80%, 85% and the 95% levels
for the Northern hemisphere (left panel) and the
Southern hemisphere (right panel).
DB-2
International Session 2003
ECMWF
• Peaks beyond 500mm/day (670mm at Anduze)
• A large area with more than 200mm in 24h
• Early warnings were available
DB-3
International Session 2003
ECMWF
DB-4
International Session 2003
ECMWF
NOAA16 9 Sept. 2002 1220UTC
DB-5
International Session 2003
ECMWF
Le Gardon
à Collias
11 Sept
9 Sept 2002
DB-6
International Session 2003
ECMWF
Forecast consistency
five consecutive T511 forecasts valid at the same time
DB-7
International Session 2003
ECMWF
T511 precipitation forecasts
cumulated over 24h and valid for: 20020908 18z to 20020909 18z
DB-8
International Session 2003
ECMWF
EPS precipitation probabilities
valid for TP cumulated over 24h: 20020908 18z to 20020909 18z
Sa 7/9
Fr 6/9
Th 5/9
We 4/9
Tu 3/9
CTRL
Prob.
RRR>50mm
Prob. (area)
RRR>50mm
DB-9
International Session 2003
ECMWF
S-France flood: Summary
 A stationary convective system generates huge amounts of
precipitation in a few hours ( ~ 600 mm/24h in some places)
over a limited area.
 The medium-range deterministic forecast is very consistent.
The synoptic pattern is correctly forecasted already 5 days in
advance. Good ability of the model to simulate the basic
ingredients for severe convection.
 EPS supports the deterministic forecast showing unusual high
probability values. EFI index gives early warning but spread a
large area.
DB-10
International Session 2003
ECMWF
Precipitation accumulated over the Po' river catchment
area predicted by the 51 EPS members started on
2 November 1994 and run for 10 days (grey lines, cyan for the control)
and the 6 nested LEPS members (violet lines, green for the control)
started on 3 November and run for 3 days. The red line depicts the
area-average over the river-catchment computed from synoptic observations.
DB-11
International Session 2003
ECMWF
Global Weather
Prediction – A Triumph
for science and
computing
Today we have global
operational forecasts
with useful skill
varying between 7 and
8 days;
During the satellite data era there has been a gain of
more than 2 days and 4 day gain since Miyakoda’s
experimental forecasts which he carried out in the late
1960s (published in 1972); the hemispheric skill that can
be achieved with the 1950s observing system is around
6 days – truly a triumph for science and computing
DB-12
International Session 2003
ECMWF
Number of used observational data per 12 UTC cycle in
ECMWF's operational assimilation system, 1997-2002.
DB-13
International Session 2003
ECMWF
DB-14
International Session 2003
ECMWF
DB-15
International Session 2003
ECMWF
FORECAST VERIFICATION 12UTC
1000hPa
GEOPOTENTIAL
ANOMALY CORRELATION
N.HEM
96
no_sat_w T+ 96
control_w T+ 96
FORECAST
no_upper_w T+ 96
LAT 20.000 TO 90.000 LON -180.000 TO 180.000
%
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DECEMBER
JANUARY
2002
2003
DB-16
International Session 2003
ECMWF
ECMWF Analysis VT:Sunday 29 December 2002 12UTC 1000hPa geopotential height
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80°N
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40°W
Wednesday 25 December 2002 12UTC ECMWF Forecast t+96 VT: Sunday 29 December 2002 12UTC 1000hPa geopotential height
0
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°N
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Four-day forecasts for
Sunday 29 December 2002
A – analysis
F1 – full system
F2 - without satellite data
40°E
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DB-17
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Wednesday 25 December 2002 12UTC ECMWF Forecast t+96 VT: Sunday 29 December 2002 12UTC 1000hPa geopotential height
20
L
20°E
International Session 2003
ECMWF
Real-time data from new research
satellites
ENVISAT from ESA, flying a range of
instruments to measure ocean waves
and ozone - LAUNCHED
AQUA from NASA, flying AIRS the first
of a new generation of high-resolution
infrared instruments - LAUNCHED
DB-18
International Session 2003
ECMWF
Major enhancements of the
operational satellite observing
system
SEVIRI on MSG, the new
generation of EUMETSAT
geostationary satellites
- 2003
IASI and other instruments on
the first generation of
EUMETSAT polar-orbiting
satellites
- LATE 2005
DB-19
International Session 2003
ECMWF
DB-20
International Session 2003
ECMWF
DB-21
International Session 2003
ECMWF
THORPEX?
A combination of inaccurate initial conditions
and errors in model formulation contribute to:
• significant failures in forecasting high-impact
weather
• the inability to extend the range of skillful
predictions beyond 7 days
• poor prediction of tropical-extratropical
interactions
• inadequate skill in predicting specific aspects of
mesoscale weather, e.g., precipitation
DB-22
International Session 2003
ECMWF
Rossby Wave Dispersion: 6-28 November 2002
Time/Long. Diagram: 250-mb Meridional Wind : 35-60 N
6 Nov
Cyclogenesis
9 Nov
India/T.C.
12 Nov
Tornadoes
Oil Tanker
Cyclogenesis
15 Nov
Snow/Ice Storm
Cyclogenesis
18 Nov
Cold-Air
21 Nov
Cyclogenesis
24 Nov
Moroccan Flood
Cold-Air
27 Nov
DB-23
Alps Flood
Foehn Wind
*UK
*
Japan
*
Cal.
International Session 2003
*
UK
Alps flood
ECMWF
THORPEX Objectives
•
advance basic knowledge of global-to-regional influences on
the predictability of high-impact weather
•
contribute to the development of a dynamically-controlled
interactive forecast system
•
consider short-range (0-3 days), medium-range (3-7 days)
and week-two forecast problems: the “middle ground”
between weather and climate
•
develop methods for assessing the economic and societal
value of improved weather forecast skill
DB-24
International Session 2003
ECMWF
Interactive Forecast System
• optimal design of fixed and adaptive observing
system
• use of targeting techniques for observing and data
assimilation
• two-way flow of information between model and
observing system
DB-25
International Session 2003
ECMWF
Driftsonde System
OrbComm
LEO Satellite
Zero-pressure
Balloon
Gondola
(24 sonde capacity)
Hourly data at flight level
6 hours
between
drops
High-resolution vertical
profiles of Temperature,
Wind, Moisture, Pressure
Ground Station
NORTH
AMERICA
DB-26
ATLANTIC OCEAN
International Session 2003
EUROPE
ECMWF
An example of possible Driftsonde
deployment from Japan
DB-27
International Session 2003
ECMWF
Numerical Weather Prediction
•
•
•
Errors in initial conditions and forecast model
dominate.
NWP centres concentrate on
–
–
sophisticated data assimilation schemes,
built round high-resolution models.
Error growth is important:
• Sensitivity to initial conditions,
• Chaotic error growth - limits to
predictability,
• THORpex international research
programme.
DB-28
International Session 2003
ECMWF
Assimilation of cloud & precipitation
Weather systems (In order of priority +
possibility?)
1. Resolved, dynamically-forced, vertical motion (eg
depressions)
2. Horizontally (but not vertically) resolved forcings
and feedback on parametrized boundary-layer
processes (eg Strato-Cu)
3. Resolved forcings and feedback on parametrized
deep convection (eg MCS, embedded convection in
fronts)
International Session 2003
DB-29
4.
Scattered convection.
ECMWF
Sources of errors
in model predictions
• Initial conditions
• Forecast model
• External forcing
Errors in all these accumulate,
and in some circumstances grow,
to limit the predictability.
DB-30
International Session 2003
ECMWF
Seasonal Prediction
• Chaotic growth  Detailed initial
conditions of the atmosphere are not
important.
• Coupled systems have components
without this rapid growth, e.g. ocean, land
surface.
• Seasonal forecasts do depend on initial
conditions for these components.
Data assimilation for coupled models.
ECMWF
DB-31
International Session 2003
Niño-3 SST hindcasts
ACC: 1987 – 1994 (32 start dates)
DEMETER multi-model
ECMWF CNRM UKMO LODYC
Persistence
DB-32
International Session 2003
ECMWF
Real-time dynamical multi-model seasonal forecast
Risk of wet / dry winter 2002/03
DB-33
International Session 2003
ECMWF
Climate Prediction
• Changes in external forcing dominate.
• Model validation and development is
crucial
• Data assimilation is important for this.
DB-34
International Session 2003
ECMWF
Coupled Data Assimilation
• Skill in seasonal predictions comes from slowly
evolving sea and land surface.
• We do not have enough observations for these; the
atmosphere is relatively better known.
Need atmosphere in coupled Data Assimilation,
even though atmosphere Initial Conditions are not
important.
• But don’t need fully coupled Data Assimilation:
– the insertion of obs into each model is independent
– with coupling, via fluxes, in the forecast steps.
DB-35
International Session 2003
ECMWF
Bias
• If a model has bias, it is impossible for Data
Assimilation to give consistent bias-free
fields and fluxes.
• Exacerbated by biased obs & Data
Assimilation methods.
Coupled Data Assimilation must give
higher priority to coping with bias than does
NWP Data Assimilation.
DB-36
International Session 2003
ECMWF
Summary
• Non-NWP Data Assimilation
has different
priorities
• Biases are unavoidable, and must be
allowed for in coupled Data Assimilation
• Re-analyses useful to validate seasonal
prediction systems
DB-37
International Session 2003
ECMWF
Prospects for NWP and Seasonal
Forecasting
• Comprehensive Earth-System forecast facilities
• Comprehensive Earth-System assimilation facilities
• Strong Satellite Capabilities
• Improving ground-based observing systems with
experimental
systems to provide guidance
• Robust and efficient Numerical methods
• Thoroughly Validated Parametrizations
• Extensive Ensemble Capabilities
• Strong Computing
• We may confidently expect
– Increasing forecast quality
– Further spin-offs and new products
DB-38
International Session 2003
ECMWF
The Weather Community can
advance Global monitoring of the
environment in:
• SYSTEMS FOR RISK ASSESSMENT
– delivering operational support to weather-related risk management
(early warning, impact assessment and reaction) in sensitive areas
for: floods; forest fires; oil spills; and support for humanitarian aid
• GLOBAL ATMOSPHERE MONITORING
– delivering regular assessments of state of the atmosphere with
particular attention to aerosols, ozone, UV radiation and specific
pollutants
• GLOBAL OCEAN MONITORING
– in support of seasonal weather predictions, global change research,
commercial oceanography and defence.
• GLOBAL VEGETATION MONITORING
– to assess carbon fluxes to/from the biosphere.
DB-39
International Session 2003
ECMWF
Areas for GMES Collaboration
Global Monitoring / Forecasting of
Greenhouse Gases
2.1 Map the
seasonal
variations of total
column amounts
of Greenhouse
Gases
2.2 Model and
assimilate ocean
colour data, to
estimate ocean
carbon uptake.
DB-40
2.3 Model and
assimilate
global aerosol
information
(to improve weather
forecasts & the use of
ocean colour data)
International Session 2003
2.4 Model and
assimilate
information on the
Land Biosphere and
carbon cycle.
ECMWF
Global Monitoring / Forecasting of Reactive
Gases: The Chemical Weather Forecast
Current operational ozone monitoring
capability is a good basis for
developing a global capability to
monitor reactive gases and
associated aerosols
3.1 Integrate chemical modules with
weather models, to provide global
assimilation & forecasts of the
distributions of
•ozone and its precursors
•sulphate aerosol
•other aerosol
Ozone
CO
The global models can drive regional
chemistry / air quality models.
DB-41
International Session 2003
ECMWF
Environmental Predictions
Environmental Predictions can be very effective if environmental models are driven
by
Global Earth-System Assimilations
Global Deterministic & Ensemble Forecasts
Inverse Model for Carbon attribution
Atmosphere
Regional Weather Model
Chemical & Aerosol Transport Model
Trajectory Model
Hydrological Model
Land
Crop Model
Fire Model
Disease Model
Ocean
Oil-spill Model
Storm Surge Model
Coastal Zone Model
DB-42
International
Session
2003Model
Regional
Ocean
ECMWF