Needs & Challenges for Urban Weather Observations Challenges in Urban Meteorology: A Forum for Users and Providers September 2004 Rockville, Maryland presented by Walter F. Dabberdt, Ph.D. Mailto:

©Vaisala | | Dabberdt_Urban Forum - Rockville, MD | Page 2 Four Major USWRP ‘Urban’ Meetings q PDT-10: Forecasting in the Urban Zone (24-26 August 1998); Sept BAMS q PDT-11: Air Quality Forecasting (6-8 November 2001); April 2004 BAMS q Community Workshop on Air Quality Forecasting (29 April - 1 May 2003); report in preparation q Community Workshop on Mesoscale Measurement Networks (6-8 December 2003);

©Vaisala | | Dabberdt_Urban Forum - Rockville, MD | Page 3 Responses to Four Questions Posed by Forum Organizers on Adequacy of Current Urban Meteorological Observations 1 - Q: Requirements for timeliness, precision and accuracy? 2 - Q: Priority measurements and observing systems? 3 - Q: What are major challenges for collecting and assimilating meteorological observations to meet users needs? 4 - Q: Adequacy of education, training and outreach?

©Vaisala | | Dabberdt_Urban Forum - Rockville, MD | Page 4 Responses to Four Questions Posed by Forum Organizers on Adequacy of Current Urban Meteorological Observations 1 - Q: Requirements for timeliness, precision and accuracy? R: Temporal resolution consistent with obtaining a stable value (~15min) R: Representativeness and spatial resolution are critical! 2 - Q: Priority measurements and observing systems? 3 - Q: What are major challenges for collecting and assimilating meteorological observations to meet users needs? 4 - Q: Adequacy of education, training and outreach?

©Vaisala | | Dabberdt_Urban Forum - Rockville, MD | Page 5 Fluid Modeling of Urban Street-Level Dispersion Hoydysh and Dabberdt, 1994 Source Wind vector

©Vaisala | | Dabberdt_Urban Forum - Rockville, MD | Page 6 (MacDonald et al., 2001) SCOS-97 mixing depths, September 4, 1997 Mixing Depth – Spatial and Temporal Variability 0300LST 1400LST L.A. Basin (Plate, 2004)

©Vaisala | | Dabberdt_Urban Forum - Rockville, MD | Page 7 Responses to Four Questions Posed by Forum Organizers on Adequacy of Current Urban Meteorological Observations 1 - Q: Requirements for timeliness, precision and accuracy? R: Temporal resolution consistent with obtaining a stable value (~15min) R: Representativeness and spatial resolution are critical! 2 - Q: Priority measurements and observing systems? R: Application-specific with considerable overlap PBL depth and structure (winds, temperature and turbulence) are perhaps the single highest priority 3 - Q: What are major challenges for collecting and assimilating meteorological observations to meet users needs? 4 - Q: Adequacy of education, training and outreach?

Urban-Mesoscale Networks: Design vs. Applications

©Vaisala | | Dabberdt_Urban Forum - Rockville, MD | Page 9 Estimating Mixing Depth Cn2Cn2 Vertical Velocity Spectral Width Mixing Depth – Data and MethodsMixing Depth – Radar Wind Profiler 0 local time 24

©Vaisala | | Dabberdt_Urban Forum - Rockville, MD | Page 10 Mixing Depth - Lidar CT25K Backscatter Mar-2000 Local Time (h) Altitude (m) Radiosonde Sounding 11:44 Potential Temperature (°C) Altitude (m) CT25K Backscatter 11:44 Backscatter (a.u.) Altitude (m) 1m CT25K BSL

©Vaisala | | Dabberdt_Urban Forum - Rockville, MD | Page 11 Responses to Four Questions Posed by Forum Organizers on Adequacy of Current Urban Meteorological Observations 1 - Q: Requirements for timeliness, precision and accuracy? R: Temporal resolution consistent with obtaining a stable value (~15min) R: Representativeness and spatial resolution are critical! 2 - Q: Priority measurements and observing systems? R: Application-specific with considerable overlap PBL depth and structure (winds, temperature and turbulence) are perhaps the single highest priority 3 - Q: What are major challenges for collecting and assimilating meteorological observations to meet users needs? R: Establishing effective public-private-academic partnerships! 4 - Q: Adequacy of education, training and outreach?

©Vaisala | | Dabberdt_Urban Forum - Rockville, MD | Page 12 Current roles of the public, private and academic sectors

©Vaisala | | Dabberdt_Urban Forum - Rockville, MD | Page 13 Future roles of the public, private and academic sectors??

©Vaisala | | Dabberdt_Urban Forum - Rockville, MD | Page 14 Implementation recommendations: Typical member roles:  The public sector members access the data for the public good; i.e. public safety. Set performance standards.  The private-sector consortium members (and possibly academic partners) use the data to create and sell various value-added products.  Academia and non-profit research centers have access to the data for educational and research purposes. The December 2003 USWRP Mesoscale Observing Systems Workshop recommended a partnership arrangement and the creation of consortia of PPA partners to develop, maintain and support regional mesoscale networks or even a composite national network.

©Vaisala | | Dabberdt_Urban Forum - Rockville, MD | Page 15 Testbeds Testbeds provide the infrastructure for transitioning from R&D to operations. The testbed needs the flexibility to test many new ideas, the expertise to judge which of them are viable, and the infrastructure to harden the sensors, algorithms and models that will generate new products for operations.

©Vaisala | | Dabberdt_Urban Forum - Rockville, MD | Page 16 Responses to Four Questions Posed by Forum Organizers on Adequacy of Current Urban Meteorological Observations 1 - Q: Requirements for timeliness, precision and accuracy? R: Temporal resolution consistent with obtaining a stable value (~15min) R: Representativeness and spatial resolution are critical! 2 - Q: Priority measurements and observing systems? R: Application-specific with considerable overlap PBL depth and structure (winds, temperature and turbulence) are perhaps the single highest priority 3 - Q: What are major challenges for collecting and assimilating meteorological observations to meet users needs? R: Establishing effective public-private-academic partnerships! 4 - Q: Adequacy of education, training and outreach? R: Inadequate!

©Vaisala | | Dabberdt_Urban Forum - Rockville, MD | Page 17 Actions/Needs ‡Need to develop methods to design urban meteorological measurement networks that are consistent with evolving and more demanding needs, especially modeling ‡Establish testbeds that involve observing systems and strategies, modeling, data assimilation, EPS, forecast products and users, and that serve multiple applications (Sydney-2000 a good example) ‡Find mechanisms to establish effective and viable Public-Private- Academic Partnerships

©Vaisala | | Dabberdt_Urban Forum - Rockville, MD | Page 18 “The times they are a-changing” (Bob Dylan, 1965) Come gather 'round people Wherever you roam And admit that the waters Around you have grown And accept it that soon You'll be drenched to the bone. If your time to you Is worth savin' Then you better start swimmin' Or you'll sink like a stone For the times they are a-changin'.

©Vaisala | | Dabberdt_Urban Forum - Rockville, MD | Page 19 “The times they are a-changing” (Bob Dylan, 1965) Come gather 'round people Wherever you roam And admit that the waters Around you have grown And accept it that soon You'll be drenched to the bone. If your time to you Is worth savin' Then you better start swimmin' Or you'll sink like a stone For the times they are a-changin'. end

©Vaisala | | Dabberdt_Urban Forum - Rockville, MD | Page 20 Candidate Meteorological Measurement Systems

©Vaisala | | Dabberdt_Urban Forum - Rockville, MD | Page 21 Selected Measurement Recommendations q Dynamic characterization of land surface q Assimilation of meteorological and chemical measurement data q Surface networks are high priority:  10km and 5min resolution q Augmentation of WSR-88D network - dual polarization - radars of opportunity - high-density, low-power networks - total lightning observations q Testbeds are key q Networks must serve multiple applications (‘no single killer application’) q Need for Public-Private-Academic partnerships q Need PBL observations with high spatial and temporal resolution