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01/04/2015 ”Urban Boundary-layer Atmosphere Network” Curtis Wood, Leena Järvi, Rostislav Kouznetsov, Ari Karppinen, Jaakko Kukkonen, Annika Nordbo, Timo.

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Presentation on theme: "01/04/2015 ”Urban Boundary-layer Atmosphere Network” Curtis Wood, Leena Järvi, Rostislav Kouznetsov, Ari Karppinen, Jaakko Kukkonen, Annika Nordbo, Timo."— Presentation transcript:

1 01/04/2015 ”Urban Boundary-layer Atmosphere Network” Curtis Wood, Leena Järvi, Rostislav Kouznetsov, Ari Karppinen, Jaakko Kukkonen, Annika Nordbo, Timo Vesala, Achim Drebs, Anne Hirsikko, Sylvain Joffre, Timo Vihma, Irene Suomi, Carl Fortelius, Ewan O’Connor, Dmitri Moisseev, Markku Kangas Thanks to co-authors and the help from many support/technical/admin staff (and many research grants including EC, Finnish Academy )

2 Why observations? Understand processes -> develop parametrizations Live data -> numerical models (e.g. data assimilation) -> climatology Validate models (AQ, CTM, NWP)

3 Why urban? Most of us live in cities (even more work in cities) NWP resolution getting finer (hence motivates physics’ devlopment )

4 What is the science? NWP -> effect of surface on atmosphere (ABL scale and smaller) AQ -> e.g. want pollutant distributions near ground ABL depth affects concentrations, especially of surface- released quantities Sat 4 th Feb 2012, 23:48 (Helsinki) Hence urban ABL Variation in space and time of wind, temperature, moisture The surface energy budget

5 Surface energy budget Net radiation: Shortwave & longwave radiation G H LE INPUTS/OUTPUTSHEAT FLUXES Net radiation – ground heat + storage = Sensible + Latent (vapour) + Anthropogenic Rn G S H LEA S A Rn

6 Helsinki UrBAN Aims Develop observation network Research high-latitude urban ABL Provide data for evaluation, assessment & improvement of urban sub-models/parametrizations in NWP/AQ models

7 Map made by Annika Nordbo, from HSY data

8 Flux stations Eddy-covariance method Tower-based measurement SMEAR-III, Torni (+more) Sensible heat Latent heat CO2 flux Particle flux momentum 1 st case-study in this presentation: 4 th September 2011 Mostly clear skies (cumulus)

9 Matemaattis-luonnontieteellinen tiedekunta / Henkilön nimi / Esityksen nimi SMEAR III Dec 2005 → 31 m EC (τ, H, LE, F c, F p ) Basic meteorology T & U profiles Gases, particles Fire Station Jul2010–Jan m EC (τ, H, LE, F c, F p ) Hotel Torni Oct 2010 → 60 m EC (τ, H, LE, F c, F p ) AJ Kieloaho JFJ Korhonen

10 Sensible heat flux

11 Scintillometer 4.3km path Kumpula-Torni Transmitter Receiver Structure parameter for T Scintillations (twinkling) due to refraction Related to temperature gradient Can be related to sensible heat flux

12 Rosa Gierens -> City-scale (Kumpula-Torni) -> Downtown (Sitra-Elisa)

13 Sodar  Single vertically-pointing antenna (1D)  5 s sounding interval  m range; with 10-m resolution  Kumpula, then Pasila ABL depth Turbulence (day) Variables:  Profile of vertical velocity  Atmospheric boundary-layer depth (based on backscatter gradient)

14 Lidar Scanning, doppler “HALO Photonics Streamline” Several km range (~30m resolution) Vertical profiles: turbulence, wind, aerosol (e.g. pollution or volcanic ash) Custom scans (any angle) Deep ABL seen by lidar Shallow ABL seen by sodar

15 01/04/2015Finnish Meteorological Institute15 r = 0.96 rmse = 0.48 m/s bias= –0.23 m/s (SMEAR-III greater than lidar) Intercomparison Case-study 2: 03 January 2012

16 Auxiliary measurements: Data sourceScience output Doppler radars2D meso-scale flow field Soundings (AMDAR, radiosonde) Vertical profiles of T, U, dd, RH Tall masts (Espoo, Isosaari) Vertical profiles of T, U, dd, RH Satellite analysesSurface temperature, gas concentrations Building and traffic dataBuilding morphology (relate to fluxes of momentum, heat), also anthropogenic flux 01/04/2015Finnish Meteorological Institute16 Useful for… – mesoscale effects? -- background data?

17 Helsinki UrBAN is among the most comprehensive urban networks Many science results already published, e.g.:  Urban carbon dioxode exchange of many annual cycles (about average for worldwide cities)  Initial anthropogenic heat flux estimate (e.g. 13 W/m2 around SMEAR-III)  Much more unstable downtown (anthrop heat flux, plus storage release) Overview

18 Strengths: Growing observational network Some collaboration with corresponding UK studies Helsinki TestBed Unique site (strong seasonality, high- latitude) Weaknesses: Moderate current funding No street canyon work Opportunities: Write proposals Bring together many people/skills (e.g. workshops) Connect with companies and customers (e.g. Vaisala, HSY) Threats: Skills too varied? Not many people’s priority No current external future funding? SWOT analysis for the observation network

19 New/planned activities: Data sourceScience output 2x EC stations? Compensate for tower flow distortion missing sectors ? Suburban ? Street canyon 3 rd scintillometer (short-path) Scintec SLS20-A ? Inner scale of turbulence Future collaborations? – apply for money to invite experts/students Finnish Meteorological Institute

20 01/04/2015 ”Urban Boundary-layer Atmosphere Network” Curtis Wood, Leena Järvi, Rostislav Kouznetsov, Ari Karppinen, Jaakko Kukkonen, Annika Nordbo, Timo Vesala, Achim Drebs, Anne Hirsikko, Sylvain Joffre, Timo Vihma, Irene Suomi, Carl Fortelius, Ewan O’Connor, Dmitri Moisseev, Markku Kangas Thanks to co-authors and the help from many support/technical/admin staff (and many research grants including EC, Finnish Academy ) Pääkaupunkiseudunortoilmakuva 2011: Espoon, Helsingin, Kauniaisten, Vantaan,Kirkkonummen ja Keravan kaupungit sekä HSY Any ideas for best use of our network?


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