Transcript Research Priorities

General comments
• Need for new observations versus new
parameterizations?
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Should explore what GCOS and others are doing
Urgent need for concerted physical process study
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in Antarctic
» Field campaign: PBL, cloud, synergy/comparison with Satellites to assist in
transfer of research satellites to operations.
» Model intercomparison over period of field study
» Build on RIME proposal
Arctic: e.g. use/acquire new obs like ASCOS
Real-time data availability important (e.g. example of concordiasi, SHEBA)
Data mining
Intercomparison of polar forecasts
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New metrics required
Scientific challenges to advance forecast skill in polar regions
• Coupled modelling – snow
- more realistic representation of (1) snow albedo
(function of ageing and temperature, aerosols, black
carbon), (2) snow fraction (hysteresis effect) and (3) snow
thermal insulation, more generally fluxes
-Limiting factor: Knowledge vs data
- potential benefits from “tiling”
-snow-vegetation interaction
-Surface roughness (over ice ridges)
-Mass balance?
- issues for NWP: (1) initialization; (2) snow over sea-ice;
(3) use of schemes developed for climate models
-importance of blowing snow? Parameterization of
Scientific challenges to advance forecast skill in polar regions
• Coupled
modelling – sea-ice and ocean
- climate perspective
- potential predictability:
- decadal scales: THC-SAT connection
- ocean memory
- seasonal scales:
- suggestion that thicker sea ice is more
predictable
-sensitivity to (1) ocean initial state; (2) near-ice-edge
conditions
- Need for enhanced operational analysis
-Needs ice thickness and snow data, albedo, etc..
-To explore predictability on seasonal scales for sea
Scientific challenges to advance forecast skill in polar regions
• Physical
processes – PBL and clouds
- the PBL problem:
-(1) assumed mesoscale spectral gap not observed in Arctic;
may be true more generally
-(2) difficulties in modelling of stable boundary layer;
-(3) conflict between PBL observations and model
parametrizations (indicate revision of stability functions and
underlying principles);
-(4) need for enhanced vertical resolution
- PBL schemes need to include clouds
-solving polar clouds needs multiple directions (PBL, surface,
microphysics, radiation)
- cloud detection in polar regions remains a challenge
-Need for new observational techniques, including aerosols.
-Highlights need for comprehensive observational studies
-How to include differences between N and S poles in NWP
-Other projects may be able to contribute (OASIS, PolarCAT,
AICI, aeronet)
Scientific challenges to advance forecast skill in polar regions
• Physical processes – free atmosphere
- Arctic:
-(1) PBL and microphysics impact mostly over ocean;
-(2) clouds play role in many feedbacks;
-(3) mixed-phase clouds and super-cooled water important;
-(4) pollution / haze / cloud-aerosol interaction need to be taken into
account (evidence of day-to-day variation)
-Seasonal cycle of aerosols
- Antarctica:
-(1) long-wave absorption due to clouds most important effect;
-(2) need new studies and measurements (not much done in past 10
years);
-(3) water and mixed-phase clouds present despite cold temperature;
-(4) urgent need for concerted cloud campaign? Not just clouds, PBL,
etc needed as well.
Scientific challenges to advance forecast skill in polar regions
• Physical
processes – orographic effects
- large-scale flow response to Greenland and Antarctica
- complex orography / effects: (1) blocking and gravitywave drag; (2) katabatic winds, rotors, barrier jets, tip jets,
coastal jets, orographic precipitation; (3) high resolution
needed; (4) initial conditions important
- But, sometimes 1km not enough…
-Link between PBL and steep terrain
-New high-resolution topographic dataset would be
helpful
- detailed model studies still required.
-More observations required for initialization
Scientific challenges to advance forecast skill in polar regions
• Physical
processes – sea-ice and ocean
- importance of (1) polynyas; (2) tides; (3) sea-ice
representation (roughness, melt ponds, extent, thickness)
- importance of coupled atmosphere-ice-ocean interaction
(fluxes)
- need of (1) detailed process studies; (2) careful
parametrizations; (3) support from observations
- Data mining: MIZEX, IPY! IICWG
- Ocean initialization a particular problem
-WGOMD – CORE
-Inclusion of ice shelves problematic. An up-to-date and
accurate land sea mask important(with shelves)
Scientific challenges to advance forecast skill in polar regions
• Data
assimilation (global)
- improving models and data assimilation leads to greater improvements than increase
in observations.
- frontiers:
-(1) improved quality control and data % used;
-better use of observations already available
-(2) new obs;
-Potential for enhanced polar VOS
-(3) novel diagnostics to assist DA tuning and observation network design (OSSE);
-(4) use of ensemble forecasts;
-(5) coupled initialization/data assimilation
-Cryospheric data assimilation using multi-sensors
- EC-PORS website: satellite task plan white paper: “satellite component of a
comprehensive cryospheric and polar region observing system”
-questions:
- gap in AMVs QC plot around 60S
- temporary reduction in Canadian radiosondes
-6 month period. No wind direction and speed for of two measurements per
day.
Scientific challenges to advance forecast skill in polar regions
• Coupled
regional reanalyses
- operation coupled analyses for polar regions
-Using coupled models
-Coupled data assimilation still far off, for now data
assimilation using coupled models is focus
- benefited from using
- common grid
- coastal anisotropic background error covariances
(quasi flow dependent)
- importance of flux coupling to be investigated
Scientific challenges to advance forecast skill in polar regions
• Polar
observing system for regional operational NWP
- NWP in polar regions depends on quality of (1) model, (2) boundary
forcing and (3) initial conditions
-Ocean models and ocean observations are a critical component
to accurate polar NWP
-Sustainability an issue
-Polar obs system: (1) insufficient density of radiosondes and surface
obs; (2) most satellite are free atmosphere; surface / lower
troposphere info lacking; (3) use of satellite data harder over land and
sea-ice than over ocean; (4) issues in use of microwave sounding
data (sea-ice emissivity, penetration depth, realistic first guess of
surface temperature)
-UAV could be useful for operations as well
-Targeted regions
-What observations are most useful for polar NWP?