General comments Need for new observations versus new parameterizations? Should explore what GCOS...
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Transcript of General comments Need for new observations versus new parameterizations? Should explore what GCOS...
![Page 1: General comments Need for new observations versus new parameterizations? Should explore what GCOS and others are doing Urgent need for concerted physical.](https://reader036.fdocuments.in/reader036/viewer/2022082819/56649e055503460f94af1d89/html5/thumbnails/1.jpg)
General comments
• Need for new observations versus new parameterizations?
• Should explore what GCOS and others are doing
• Urgent need for concerted physical process study– 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– New metrics required
![Page 2: General comments Need for new observations versus new parameterizations? Should explore what GCOS and others are doing Urgent need for concerted physical.](https://reader036.fdocuments.in/reader036/viewer/2022082819/56649e055503460f94af1d89/html5/thumbnails/2.jpg)
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 sublimation-Cryosat may help?-Use of “A-train” for validation studies
![Page 3: General comments Need for new observations versus new parameterizations? Should explore what GCOS and others are doing Urgent need for concerted physical.](https://reader036.fdocuments.in/reader036/viewer/2022082819/56649e055503460f94af1d89/html5/thumbnails/3.jpg)
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 ice forecasts?
![Page 4: General comments Need for new observations versus new parameterizations? Should explore what GCOS and others are doing Urgent need for concerted physical.](https://reader036.fdocuments.in/reader036/viewer/2022082819/56649e055503460f94af1d89/html5/thumbnails/4.jpg)
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)
![Page 5: General comments Need for new observations versus new parameterizations? Should explore what GCOS and others are doing Urgent need for concerted physical.](https://reader036.fdocuments.in/reader036/viewer/2022082819/56649e055503460f94af1d89/html5/thumbnails/5.jpg)
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.
![Page 6: General comments Need for new observations versus new parameterizations? Should explore what GCOS and others are doing Urgent need for concerted physical.](https://reader036.fdocuments.in/reader036/viewer/2022082819/56649e055503460f94af1d89/html5/thumbnails/6.jpg)
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 gravity-wave 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
![Page 7: General comments Need for new observations versus new parameterizations? Should explore what GCOS and others are doing Urgent need for concerted physical.](https://reader036.fdocuments.in/reader036/viewer/2022082819/56649e055503460f94af1d89/html5/thumbnails/7.jpg)
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)
![Page 8: General comments Need for new observations versus new parameterizations? Should explore what GCOS and others are doing Urgent need for concerted physical.](https://reader036.fdocuments.in/reader036/viewer/2022082819/56649e055503460f94af1d89/html5/thumbnails/8.jpg)
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.
![Page 9: General comments Need for new observations versus new parameterizations? Should explore what GCOS and others are doing Urgent need for concerted physical.](https://reader036.fdocuments.in/reader036/viewer/2022082819/56649e055503460f94af1d89/html5/thumbnails/9.jpg)
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
![Page 10: General comments Need for new observations versus new parameterizations? Should explore what GCOS and others are doing Urgent need for concerted physical.](https://reader036.fdocuments.in/reader036/viewer/2022082819/56649e055503460f94af1d89/html5/thumbnails/10.jpg)
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?