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Urban Climate Research Group

Arizona State University

 

 

Urban Canopy Model

Sensor Network

Subsurface Transport

Turbulent Dispersion

 

Sensor Network for Urban Environmental Monitoring

 

Experimental measurements through field campaigns are of paramount importance in studying the physics of energy/water transport in the atmospheric boundary layer (ABL). While numerous sensing instruments and networks have been set up for natural terrains, e.g. forests, mountains, wetlands, etc., field measurements in urban areas remains scarce, primarily due to practical difficulties associated with logistics and management. On the other hand, the study of urban ABL phenomena, hitherto at its infancy, relies heavily on field measurements to resolve the extremely high surface heterogeneity and localized driving mechanisms. Therefore there is a worldwide imperative need of more field measurement campaigns to be conducted in urban areas, in particular those targeted on the long term monitoring of urban environment, to validate and guide the rapidly advanced urban models.

 

Our group is planning to deploy a distributed sensor network in the Greater Phoenix area for long-term monitoring of the local urban environment. Sensing instruments in the network include (a) rooftop Eddy Covariance (EC) stations, (b) distributed Sensorscope® wireless weather stations, (c) Scintillometer measurement across street canyons, (d) SODAR-RASS system as ABL profiler, and (e) miscellaneous sensors.

 

 

Eddy Covariance station

 

Roof top EC station consists of Campbell sonic anemometers and gas analyzers with high frequency (10-20 Hz) measurements, Vaisala air temperature/humidity sensor, Apogee infrared gun, Hukseflux 4-component radiometer, and regular Young cup anemometer. The main purpose of an EC tower is to measure turbulent fluxes (sensible, latent, CO2) using eddy-covariance technique. EC flux measurements cover relatively large source (footprint) areas, which range from neighborhood to city scales depending on the elevation of towers.

 

Wireless station network

 

The distributed wireless network consists of 12 distributed weather stations (manufactured by Sensorscope®), situated on both roof and street levels. Each station include a cup anemometer (wind speed and direction), a solar radiometer (solar radiation), a tipping bucket (rain precipitation), an air temperature/humidity sensor, an IR gun (surface temperature), and a soil probe (soil moisture/temperature). All stations are autonomous and completely powered by solar energy, with minimum maintenance required. Intra-station communication is through radio waves. All data packages are coded and sent to master stations which contain cell phone SIM cards and send data to the main website through telecommunication. Monitored meteorological data are published online at http://www.climaps.com/ in real time.

 

 

Scintillometer

 

Scintillometer is a great tool for measurement of turbulent heat fluxes across a street canyon. Unlike EC station, scintillometry technique us based on turbulent structure functions.

 

SODAR/RASS system

 

This device measures vertical profiles of wind speed and temperature in the atmospheric surface layer (up to 500 m).