1. QUESTION: ARE CURRENT MET OBSERVATIONS ADEQUATE FOR URBAN APPLICATIONS? R. P. Hosker, Jr. NOAA-Air Resources Laboratory Atmospheric Turbulence & Diffusion Division Oak Ridge, TN 37830 ray.hosker@noaa.gov My short answer: mostly NO.

2. CITIES ARE NOT LIKE RURAL AREAS! Sketch by Oke and Rotach, in Piringer et al, 2002: WASP-Focus, 2, pp 1-16.

3. SCIENCE ISSUES WITH CURRENT URBAN OBSERVING SYSTEMS: Inadequate resolution of spatial scales within urban areas. Few observations in the vertical – but very important for dispersion predictions in urban areas. Representativeness a major problem in cities, espec. in complex environments (e.g., terrain, coastal). Remote sensing/averaging an answer? Limited guidance for siting instruments in urban areas, espec. in CBDs.

4. NON-SCIENCE ISSUES WITH CURRENT URBAN OBSERVING SYSTEMS: Adequate funding & long-term commitments for urban measurement networks. Need lawmaker understanding and support. Siting problem #1 – owner permission often driven by liability worries. How to fix? Siting problem #2 – cities change; site characteristics vary. Need continuity in obs. Siting problem #3 – some useful instrument systems are not neighbor-friendly. Need to adjust design criteria for urban instrumentation.

5. 5 AREAS OF SPECIAL INTEREST FOR URBAN MET OBSERVATIONS Severe Weather (storms, floods, heat, cold) Homeland Security (hazardous releases) Air Quality (air pollutants and products) Water Quality (transfer of airborne materials) Climate (long term changes and trends) A request was made to add fire weather to these; perhaps really a special case of severe weather?

6. Met Requirements For: Severe Weather. Resolve sub-urban scale spatial variability. Representative sites. Rapid updates; robust comms & power; reasonable accuracy. –Current systems OK? Only in some places. Need more networks.

7. Met Requirements For: Homeland Security. WD is critical. Resolve local scale variability of wind & T fields both horizontally & vertically. Turbulence info. Rapid updates; robust comms. Ability to recognize CBR release. –Current systems OK? Generally, no. Need specialized integrated networks & vertical data, coupled to modeling.

8. Met Requirements For: Air Quality. Resolve sub-urban scale variation of winds, T, mixing layer depth. Photochemistry variables important. Concentration data. Hourly updates. Solid calibrations. –Current systems OK? Generally, not quite. Need enhanced networks, vertical data.

9. Met Requirements For: Water Quality. Resolve sub-urban or smaller scale variability of precip (location & rate), run-off. –Current systems OK? Perhaps, if using radar obs. to supplement local precip measurements.

10. Met Requirements For: Climate. Need regionally representative values of T, precip, multi-wavelength solar, etc. Need high accuracy and high precision. Long-term (decades to centuries) unchanging sites. High quality calibrations; extensive metadata; low data loss. –Current systems OK? Only in some places. Need firm commitment to QUALITY. Need more urban sites.

11. Suggested Observation Priorities: Public Safety. Severe weather obs. & warnings. Homeland security obs & warnings. Design nets (hardware, placement) to reduce human risk. Public Health, Environment. Air & water quality- related obs. Design integrated networks to assist rational decision-making, so as to reduce urban dweller exposures. Improved Understanding. Climate obs. Long- term maintenance commitments essential. Urban & other climatically sensitive regions under- represented.