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T-NAWDEXTHORPEX - North Atlantic Waveguideand Downstream Impact Experiment
Outline of scientific background
Heini Wernli, Andreas Dörnbrack, George Craig, Sarah Jones
with contributions from:Huw Davies, Pat Harr, John Methvenand participants of 1st planning meeting (Erding, Feb 2009)
T-NAWDEX
Has been proposed by the THORPEX working group Predictability and Dynamical Processes for the European THORPEX Science Plan
Its overarching scientific goal is to investigate in detail thephysical processes that are primarily responsible for degradation in 1-7 day forecast skill in global prediction systems and of their representation in NWP models.
Planned for autumn 2012 as an international field experiment in conjunction with HYMEX - the Hydrological Cycle in the Mediterranean Experiment
T-NAWDEX will have - experimental (international field experiment) and - theoretical/diagnostic/modelingresearch components
which investigate the different phases of wave guide disturbances:
1) Triggering of wave guide disturbances by different dynamical processes
2) Downstream evolution of the disturbances along the wave guide
3) Downstream impact of wave guide disturbances over Europe and North Africa
Triggering Science Issues1. What are the important triggering mechanisms, their
climatology and their predictive skill? ---- Underlying science questions that need to be examined before the field program and retested during the field phase
2. Organized diabatic forcing is one main triggering mechanism and the triggering mechanisms include:
1. Diabatic processes in developing extratropical cyclones
2. Warm conveyer belt/negative PV processes
3. Tropical convection including ETs moving energy into the wave guide
4. Polar positive PV features
5. Orography, especially associated with Greenland
6. Upstream unknowns (MJO, etc)
PV error on 315 K(forecast - analysis)
Triggering: Sources of errors in upper-level PV field
[pvu]2-pvu tropopauseforecast, analysis
from Marco Didone
analysis forecastpvu
from Marco Didone
Lagrangian history (96 hour) from positive & negative “PV error” regions
Triggering: Sources of errors in upper-level PV field
Downstream Evolution Science Issues
• What are the major forecast issues associated with the structural evolution of the waveguide?
• Does the formation of PV streamers over the western and central Atlantic, contrast with what happens at the end of the storm track over the eastern Atlantic?
• relative role of baroclinic processes• relative role of diabatic processes
• How do low-PV anomalies evolve as they move downstream? • effect of cirrus clouds, radiation, mixing• Warm conveyor belt origin• tropical cyclone origin• tropical convection origin• role(s) of diabatic processes on magnitude and timing of forecast errors• role(s) of processes acting over a variety of space and time scales
• synoptic scale associated with primary wave• diabatic Rossby waves
ana +3.5
fc +3.5
ana +5
fc +5
-
WCB
-+
-
WCB too weak
Warm conveyor belts & downstream impacts
MODIS (Aqua) 14:55 UTC
24 November 2003
Horizontal wind speed
Difference LIDAR - ECMWF analysis
Substantial analysis errors associated with intense wind features
N S
Example: Wind lidar observations of Greenland tip jet
from Andreas Dörnbrack
Downstream Impacts Science Issues
• Focus: cyclonic features, including fronts, and associated high impact weather
• Geography: east of 15W.
• Strategy: detailed measurements in the vicinity of cyclonic features, in both clear & cloudy areas, to:
• Assess the local influence of diabatic and other physical processes on the development of significant features
• Assess the relative influence of these processes in determining the location of high-impact weather such as severe wind & precipitation events,
• Ultimately promote numerical model development in the key process areas.
PV distribution on 310 K surface
Error > 15 m/s
Wind speed
Aircraft measurements
ECMWFanalysis
NCEPanalysis
Example: Aircraft observations within upper-level jet stream
from Sandro Buss & Huw C. Davies
T-NAWDEX: Partners & funding componentsGermany (DLR, Karlsruhe, Munich, Hohenheim)
HALO-THORPEX: so-called “demo mission” for the new German
research aircraft HALO
(~50 flight hours - tentative)
Switzerland (ETH Zürich)
HALO flight hours (~ 30 - tentative)
United Kingdom (East Anglia, Reading, Manchester, Leeds)
FAAM pilot flights in 2010
NERC application
France Linkage with HYMEX, joint activities envisaged
U.S.A. HIAPER
Canada
Others?
North American THORPEX Interests in T-NAWDEX Focus on: Triggering of wave guide disturbances by different
dynamical processes
Dynamical Processes:TROPICAL origin:• Extratropical transition of Atlantic hurricanes;• Organized tropical convection.
MIDLATITUDE origin:• Warm conveyor belts in extratropical cyclones over the western Atlantic or
eastern North America;• Downstream development from extratropical cyclones originating in the North
Pacific storm track;• Diabatic Rossby waves - as a combined tropical/extratropical interaction.
POLAR origin:• Upper-level PV anomalies;• High-latitude orographic forcing.
HIAPER
North American THORPEX Interests in T-NAWDEX
Potential Contribution:– Observations of the evolution and structure of the dynamical processes
associated with the triggering of wave-guide disturbances;• Remote sensing• In situ observations with the
High-performance Instrumented Airborne Platform for Environmental Research (HIAPER) G-V aircraft
– High-resolution modeling– Data assimilation experiments– Model intercomparisons– Coordination with the operational hurricane field program operated by the
NOAA Atlantic Oceanographic and Meteorological Laboratory/ Hurricane Research Division (AOML/HRD)
Complement to operations conducted downstream by European THORPEX
UK Science Focus in T-NAWDEX
Focus on: Downstream evolution of wave guide disturbances by different dynamical processes
Focus on• moist diabatic processes within mid-latitude weather systems;• their influence on system evolution and predictability,• and their sensitivity to upstream initial conditions.
Dynamical processes from global to convective scale are:1. Triggering of persistent Rossby wave patterns across NH (e.g., summer 2007
and extreme rainfall across UK).2. Moist baroclinic growth (diabatic Rossby waves etc).3. Influence of surface fluxes on system development.4. Influence of moist processes on negative PV anomalies in outflow of warm
conveyor belts and their downstream development.5. Diabatic erosion of quasi-stationary tropopause anomalies.6. Influence of diabatic processes on mesoscale structures.7. PV anomaly creation on the cloud updraft/system scales and integrated effect
on parent system.
UK contribution to T-NAWDEX field experiment in 2012
• FAAM BAe146 aircraft– Focus on low-mid level diabatic processes
(e.g., water phase change, BL fluxes over ocean, mixing processes on mesoscale and smaller)
– Based from UK for several months– Systems developing near Europe
• UK ground-based network– Upwind of the continental Europe!– Profiles and boundary layer observations– RADAR coverage system structure and evolution
European THORPEX Interests in T-NAWDEX Focus on: Downstream evolution and impacts of wave guide
disturbances by different dynamical processes
HALO - High Altitude and Long Range Research Aircraft
Oberpfaffenhofen, Germany, 24 January 2009
Key specifications:- max. altitude more than 15 km- range well above 10000 km or more than 10 flight hours- maximum payload of 3 tons
Demo-Mission HALO-THORPEX as nucleus forT-NAWDEX field phase
T-NAWDEX Time Schedule
2009 1st T-NAWDEX Planning Workshop 19/20 Feb. in Erding/Germany
Writing of the Science Planscientific aims, questions and methods
(theoretical, numerical, experimental)
Start of theoretical/modeling projects
2010 Preparation of Implementation Plan
UK FAAM T-NAWDEX Pilot Flights (Jan/March)
further national/international cooperation and fund raising
2012 Field experiment (in autumn)
Summary
T-NAWDEX is an international PDP-oriented field THORPEX field experiment scheduled for autumn 2012 - plus accompanying theoretical/diagnostic/modeling studies
It will primarily investigate the physical processes associated with the triggering, propagation and breaking of wave-guide disturbances and their representation in models and analyses
Key words: PV gradients, jet stream, diabatic PV modification, ET, explosive cyclogenesis, warm conveyor belts, surface fluxes, turbulence, RW breaking, heavy precipitation, damaging surface winds
Contributions to T-NAWDEX are welcome!Next (2nd) planning workshop: ~ spring 2010Contact: Andreas Dörnbrack [email protected]
Heini Wernli [email protected]
