UBC Micrometeorology - Urban Flux Tower

Vancouver Sunset - Urban Climate Research Tower

by Andreas Christen⁽¹⁾, Mark Johnson⁽²⁾, Ian McKendry⁽¹⁾,and Tim Oke⁽¹⁾
current scientific collaborations with Nicholas Coops⁽³⁾, Ronald Kellett ⁽⁴⁾, Sue Grimmond⁽⁵⁾, and James Voogt⁽⁶⁾.

⁽¹⁾ University of British Columbia, Department of Geography, Vancouver, BC, Canada.
⁽²⁾ University of British Columbia, Department of Earth and Ocena Sciences and IRES, Vancouver, BC, Canada.
⁽³⁾ University of British Columbia, Forestry, Vancouver, BC, Canada.
⁽⁴⁾ University of British Columbia, School of Architecture and Landscape Architecture, Vancouver, BC, Canada.
⁽⁵⁾ King's College London, Department of Geography, London, UK.
⁽⁶⁾ University of Western Ontario, Department of Geography, London, ON, Canada.

The 30m urban climate tower located at the Mainwaring substation of BC Hydro in Vancouver, BC, named "Vancouver-Sunset", was erected in 1978. It is a unique urban climate research facility which has been in semi-continuous operation since its construction, and recently been extended to boundary layer remote sensing and trace-gas measurements. It is the core facility in a programme of research at UBC Geography and SWAL into the fundamental meteorological, climatological, hydrological, and biogeochemical processes underlying the modification of the land-atmosphere exchange and biogeochemical cycling by cities.

Current research and collaborations based on measurements at this site contribute to the development of new models that will support weather forecasting and climate projections in cities, dispersion modelling, air pollution meteorology, greenhouse gas emission modelling, and conservation of water resources in the context of sustainable urban design and planning.

Interactive panorama from the top of the flux tower at Vancouver-Sunset, also available in high-resolution for download with labels. Click on image and drag mouse to pan, use ↑ and ↓ keys to zoom in and out.

2-D anemometer-thermometer on top of the tower in 1989 (Photo: M. Roth)
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Research at the tower 'Vancouver-Sunset' since 1978 was central in developing our understanding of the environment of cities. The long-term research programme at this tower lead by Prof. T. R. Oke has gained international interest and the findings from this site are the basis of methods adopted in many other cities.

Tower in 2008

Those studies have provided results concerning such features as the radiation budget of the urban surface, the energy balance of the urban surface, the water balance of the surface, the nature of atmospheric turbulence over a rough surface, suburban evapotranspiration, the height of the urban mixed layer, the vertical distributions of temperature and wind velocity in the lowest 600 m, the carbon dioxide concentration and fluxes in a suburb, etc. In many cases these are pioneering investigations where these observations were the first to be conducted anywhere. The research at the tower has also resulted in 46 papers published in the scientific literature. The tower has been further used to test prototype instrument systems and was involved in collaborative research projects with Indiana University, University of Kyoto, Japan and ETH, Zürich.

Visualization of the LIDAR dataset (N. Coops / R. Tooke)
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Vancouver-Sunset is part of the IAUC Urban Flux Network and a 10-city database called MUHD (Multi-city Urban Hydrometeorological Database) used in international comparisons. It is further central infrastructure in the CFCAS network 'EPiCC - Environmental Prediction in Canadian Cities' (2006-2010).

This site and the surrounding area within a 1 km radius has its characteristics documented in the form of a 50m raster Geographic Information System based on a recent high-resolution LiDAR scan at 1 m resolution.

Instrumented set-up and water monitoring in the neighborhood of the tower.
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The tower measurements are complemented by year-round surface obseravtions. Several homes in the area are monitored for water use, space heating requirements, and soil hydrology of the yards. Those urban hydrology measurements allow monitoring the urban water balance and to validate models that ultimately support conservation of water resources in the context of sustainable urban design and planning.

Further, the site hosts a ceilometer to remotely determine the mixed layer height, a critical parameter to validate weather and air pollutant forecasts.

Selected publications on Vancouver-Sunset (chronological order):

Oke, T.R., 1979: "Advectively-assisted evapotranspiration from irrigated urban vegetation", Boundary-Layer Meteorology, 16, 167-174.

Steyn, D.G. and T.R. Oke, 1980: "Effects of a scrub fire on the surface radiation budget", Weather, 35, 212-215.

Oke, T.R., Kalanda, B.D. and D.G. Steyn, 1980: "Parameterization of heat storage in urban areas", Urban Ecology, 5, 45-54.

Kalanda, B.D., Oke, T.R. and D. Spittlehouse, 1980: "Suburban energy balance estimates for Vancouver, B.C., using the Bowen ratio-energy balance approach", Journal of Applied Meteorology, 19, 791-802.

Oke, T.R., 1982: "The energetic basis of the urban heat island", Quarterly Journal Royal Meteorological Society, 108, 1-24.

Steyn, D.G. and T.R. Oke, 1982: "The depth of the daytime mixed layer at two coastal sites: A model and its validation", Boundary-Layer Meteorology, 24, 161-180.

Oke, T.R. and J.H. McCaughey, 1983: "Suburban-rural energy balance comparisons: An extreme case", Boundary-Layer Meteorology, 26, 337-354.

Cleugh, H. and T.R. Oke, 1986: "Suburban-rural energy balance comparisons in summer for Vancouver, B.C." Boundary-Layer Meteorology, 36, 351-369.

Grimmond, S., Oke, T.R. and D.G. Steyn, 1986: "Urban water balance I: A model for daily totals." Water Resources Research, 22, 1397-1403.

Grimmond, S., and T.R. Oke, 1986: "Urban water balance II: Results from a suburb of Vancouver, B.C." Water Resources Research, 22, 1404-1412.

Oke, T.R. and H.A. Cleugh, 1987: "Urban heat storage derived as energy balance residuals." Boundary-Layer Meteorology, 39, 233-246.

Ross, S.L. and T.R. Oke, 1988: "Tests of three urban energy balance models", Boundary-Layer Meteorology, 44, 73-96.

Oke, T.R., 1988: "The urban energy balance", Progress in Physical Geography, 12, 471-508.

Roth, M., Oke, T.R. and D.G. Steyn, 1989: "Velocity and temperature spectra and cospectra in an unstable suburban atmosphere", Boundary-Layer Meteorology, 47, 309-320.

Oke, T.R., 1989: "The micrometeorology of the urban forest." Philosophical Transactions of the Royal Society of London, B324, 335-349.

Oke, T.R., H.A. Cleugh, S. Grimmond, H.P. Schmid and M. Roth, 1989: "Evaluation of spatially-averaged fluxes of heat, mass and momentum in the urban boundary layer", Weather and Climate, 9, 14-21.

Oke, T.R., 1989: "The climatology of the Greater Vancouver Regional District", GVRD Air Management Plan-Stage 1, Appendix A1, Concord Scientific Corporation/B.H. Levelton & Associates Ltd., Vancouver, A1-1 - A1-20.

Schmid, H.P. and T.R. Oke, 1990: "A model to estimate the source area contributing to surface layer turbulence at a point over patchy terrain", Quarterly Journal Royal Meteorological Society, 116, 965-988.

Schmid, H.P., Cleugh, H.A., Grimmond, C.S.B., and T.R. Oke, 1990: "Spatial variability of energy fluxes in suburban terrain", Boundary-Layer Meteorology, 54, 249-276.

Grimmond, C.S.B. and T.R. Oke, 1991:"An evapotranspiration-interception model for urban areas", Water Resources Research, 27, 1739-1755.

Grimmond, C.S.B., Cleugh, H.A. and T.R. Oke, 1991: "An objective heat storage model and its comparison with other schemes", Atmospheric Environment, 25B, 311-326.

Grimmond, C.S.B., 1992: "The suburban energy balance: methodological considerations and results for a mid-latitude west coast city under winter and spring conditions", International Journal of Climatology, 12, 481-497.

Schmid, H.P. and T.R. Oke, 1992: "Scaling North American urban climates by lines, lanes and rows", In Geographical Snapshots of North America, Janelle, D.G. (ed.), Guilford Press, New York, 395-399

Roth, M. and T.R. Oke, 1993: "Turbulent transfer relationships over a suburban surface. Part I: Spectral characteristics", Quarterly Journal Royal Meteorological Society, 119, 1071-1104.

Roth, M., 1993: "Turbulent transfer relationships over a suburban surface. Part II: Integral statistics", Quarterly Journal Royal Meteorological Society, 119, 1105-1120.

Roth, M. and T.R. Oke, 1993: "Comparison of modelled and "measured" heat storage in suburban terrain", Contributions to Atmospheric Physics, 67, 149-156.

Chen, J.M. and T.R. Oke, 1993: "Mixed-layer heat advection and entrainment during the sea breeze", Boundary-Layer Meteorology, 68, 139-158.

Roth, M. and T.R. Oke, 1994: "Comparison of modelled and "measured" heat storage in suburban terrain", Beiträge zur Physik der Atmosphäre, 67, 149-156.

Grimmond, C.S.B. and T.R. Oke, 1995 "Comparison of heat fluxes from summertime observations in the suburbs of four North American cities", Journal of Applied Meteorology, 34, 873-889.

Roth, M. and T.R. Oke, 1995: "Relative efficiencies of turbulent transfer of heat, mass and momentum over a patchy urban surface", Journal of the Atmospheric Sciences, 52, 1863-1874.

Gryning, S.-E. and E. Batchvarova, 1996: "A model for the height of the internal boundary layer over an area with an irregular coastline", Boundary-Layer Meteorology.

Voogt, J.A. and T.R.Oke, 1997: “Complete Urban Surface Temperatures”, Journal of Applied Meteorology, 36, 1117-1132.

Voogt, J.A. and T.R. Oke, 1998: "Effects of surface geometry on remotely-sensed surface temperature", International Journal of Remote Sensing, 19, 895-920.

Voogt, J.A. and T.R. Oke, 1998: "Radiometric temperatures of urban canyon walls obtained from vehicle traverses", Theoretical and Applied Climatology, 60, 199-217.

Spronken-Smith, R.A. and T.R. Oke, 1998: “Survey of the thermal regime of urban parks in two cities with different summer climates”, International Journal of Remote Sensing, 19, 895-920.

Grimmond, C.S.B., King, T.S., Roth, M. and T.R. Oke, 1998: “Aerodynamic roughness of urban areas derived from wind observations”, Boundary-Layer Meteorology, 89, 1-24.

Grimmond, C.S.B. and T.R. Oke, 1999: “Heat storage in urban areas”, Journal of Applied Meteorology, 38, 922-940.

Grimmond, C.S.B. and T.R. Oke, 1999: “Aerodynamic roughness of urban areas derived from analysis of surface form”, Journal of Applied Meteorology, 38, 1262-1292.

Grimmond C.S.B. and T.R. Oke 1999. Rates of evaporation in urban areas. Impacts of Urban Growth on Surface and Ground Waters. International Association of Hydrological Sciences, Publication No. 259, 235-243.

Grimmond, C.S.B. and T.R. Oke, 2002: “Turbulent heat fluxes in urban areas: observations and a Local-scale Urban Meteorological Parameterization Scheme (LUMPS)”, Journal of Applied Meteorology, 41, 792-810.

Masson, V., C.S.B. Grimmond and T.R. Oke, 2002: “Evaluation of the Town Energy Balance (TEB) scheme with direct measurements from dry districts in two cities”, Journal of Applied Meteorology, 41, 1011-1026.

Voogt, J.A. and T.R. Oke, 2003: “Thermal remote sensing of urban climates”, Remote Sensing of Environment, 86, 370-384.

van der Kamp, D., McKendry, I.G., Wong, M., Stull, R, 2008: Lidar Ceilometer Observations and Modeling of a Fireworks Plume in Vancouver, British Columbia, Atmospheric Environment, 42, 7174-7178

van der Kamp, D. and McKendry, I.G. 2008: Comparison of Tethered Balloon Vertical Profiles of Particulate Matter Size Distributions with Lidar Ceilometer Backscatter in the Nocturnal Urban Boundary Layer International J. Environment and Pollution, submitted.

Goodwin, N.R. Coops, N.C, Tooke, R.T., Christen, A., Voogt, J.A. 2009: 'Characterising urban surface cover and structure with airborne LiDAR technology'. Canadian Journal of Remote Sensing, 35 (3), 297-309.

McKendry I. G., van der Kamp D., Strawbridge K.B., Christen A., Crawford B., 2009: 'Simultaneous observations of boundary-layer aerosol layers with CL31 ceilometer and 1064/532 nm lidar'. Atmos. Environ.

Järvi L., Grimmond C.S.B., Christen, A. 2011: 'The Surface Urban Energy and Water Balance Scheme (SUEWS): Evaluation in Los Angeles and Vancouver'. J. Hydrol., 411 (3-4), 219-237.

Christen, A., Coops N.C., Crawford B.R., Kellett R., Liss K.N., Olchovski I., Tooke T.R., van der Laan M., Voogt J. A., 2011: 'Validation of modeled carbon-dioxide emissions from an urban neighborhood with direct eddy-covariance measurements, Atmos. Environ., 45, 6057-6069.

Technical reports

	EPiCC Technical Report #1 - Processing and quality control procedures of turbulent flux measurements during the Vancouver EPiCC experiment.
	EPiCC Technical Report #2 - Soil properties at the Vancouver EPiCC experimental sites.
	EPiCC Technical Report #3 - Vegetation characteristics at the Vancouver EPiCC experimental sites.
	EPiCC Technical Report #4 -Statistics on the built infrastructure at the Vancouver EPiCC experimental sites.
	Christen, A., Coops N., Kellett R., Crawford B., Heyman E., Olchovski I., Tooke R., van der Laan M. (2010): A LiDAR-Based Urban Metabolism Approach to Neighbourhood Scale Energy and Carbon Emissions Modelling. University of British Columbia, 2010 supported by Natural Resources Canada, 104pp.

View of the Eddy-Covariance System on top of the tower to measure fluxes of sensible heat, water, carbon-dioxide and methane.

Site Characteristics

Longitude / Latitude	123.0784ºW 49.2261ºN
Height of tower	28m a.g.l
Average height of roofs	5.3m [4.9m]
Characteristic (max) building height	7.9m [7.1m]
Plan area of buildings	29% [23%]
Plan area of trees	12% [12%]
Plan area of ground vegetation	22% [20%]
Plan area of impervious ground	37% [45%]
Building density	12.8 Bldg./ ha
Tree density	17.1 Stems / ha
Population density	64.1 Inh./ ha

If not stated otherwise, values are given for 500 m radius around tower, Values in square brackets are weigthed averages of the long-term turbulent source area (May 2008-Apr 2010).

Sky-view / vegetation state photos

Data Products

Historical data graphs for the Vancouver EPiCC experiment (2008-*).

Realtime data from Vancouver-Sunset.

Browse through available database entries.

Data Tables

Air Temperature (2m)	2008	2009	2010	2011	2012
Soil Temperatures (-5cm)	2008	2009	2010	2011	2012
Soil Water Content	2008	2009	2010	2011	2012
Solar Irradiance	2008	2009	2010	2011	2012
Net Radiation	2008	2009	2010	2011	2012
Evapotranspiration	2008	2009	2010	2011	2012
Wind Velocity (26m)	2008	2009	2010	2011	2012

Model and Remote-Sensing Products

Raster files of cover fractions and vegetation data for Vancouver-Sunset.

Long-term source areas for Vancouver-Sunset.

Photos

Automatic Hourly Photos (restricted access)
Soil Carbon Sampling Locations (2008/09)
Vegetation Samples (2009)

Acknowledgements

This research activity has been funded by:

The Canadian Foundation for Climate and Atmospheric Sciences funded the operation from 2006-2009 as part of the Network Grant 'Environmental Prediction in Canadian Cities' (Oke and Voogt). Selected research infrastructure was supported by NSERC RTI (Christen, #344541-0), NSERC Discovery Grants (Christen, Oke) and the Canada Foundation for Innovation (Christen).

We thank BC Hydro for their long-term support and permission to operate this unique research infrastructure in one of their substations.

Since 2006, the following individuals contributed significantly to operation and data-collection: Ben Crawford (UBC), Nicholas Goodwin (UBC), Adrian Jones (UBC), Rick Ketler (UBC), Kate Liss (UBC), Ivan Liu (UBC), Kathryn McCreary (City of Vancouver),Chad Siemens (UBC), Rory Tooke (UBC), Derek van der Kamp (UBC), Mike van der Laan (UBC).