Microclimatological Instrumentation Lethbridge Microclimate Station (Flanagan) Trent Weather Station (Lafleur)
Temperature Measurement Thermocouple 2 wires of different composiotion joined by an electrical source Electrical resistance sensitive to temperature Resistance is measured and coverted to temperature information Thermister The hotter it gets, the less power it lets through Resistance is measured and converted to temperature information
Temperature and Relative Humidity Temperature and RH sensors housed in Gill Radiation Shield Relative humidity sensor detects vapour adsorption onto a sulfonated polystyrene surface Temperature Sensor thermister Function of Shields: Protect sensor from radiation (especially incoming shortwave and outgoing longwave radiation) while allowing air to pass.
Stevenson Shield An earlier radiation shield often used with wet and dry bulb thermometers Photo: Trent Weather Station
Rainfall and Snowfall Measurements Precipitation Gauge with Nipher Shield
Wind Speed and Direction Cup anemometer signal frequency converted to windspeed Wind vane
Sonic anemometer Sound waves measure wind speed and temperature Time of flight for a sonic impulse to travel from a transmitting to a receiving transducer in both directions determines wind speed and direction Sonic Transducers
Why is this sonic anemometer placed so much higher than it would be placed over a grassland or a peatland ? Source: University of Colorado (African savanna site)
Micrometeorological Tower
Yikes !
Radiation Measurements Shields made of materials appropriate for desired wavelength (eg. polyethylene for net radiation – transparent to both longwave and shortwave energy) Millivolt signals are proportional to the radiation level Net radiometer
Pyranometer Measures solar radiation on planar surface Pyrgeometer Measures infrared (longwave) radiation UV-B Radiometer Measures ultraviolet solar radiation on planar surface
Field Station Tambito al Cocal River Base camp 2º30´25´´N, 77º00´02´´W, 1450 m Photo taken from microclimate station
Juntas, El Tambo, Cauca, Colombia 901 m asl
Radiation Measurements Also: pyranometer for broadband incoming radiation LL LL KK K (not visible) UV-A
Radiation Data
More radiation sensors… Source: University of Colorado
Diffuse Radiation Measured using a shade disk Radiation from entire sky except from within 3 of Sun
Heat Flux Plate Senses conductive heat transmission in the medium within which it is buried Used for soil energy balance studies Voltage proportional to heat flux through plate
Sensible and Latent Heat Fluxes Eddy correlation (later) Sonic anemometer measurements of vertical velocity and temperature Krypton hygrometer measurements of water vapour density
Krypton Hygrometer Source emits in the nm range for which absorption by water vapour is strong and other gases do not absorb Detector senses amount of radiation received in this range Baseline established by conventional measurements
Old Fashioned Raingauge Parque Munchique Cauca, Colombia
Tipping Bucket Raingauge Each ‘tip’ is logged by the datalogger
“Leaf’ Wetness Sensor
Leaf Wetness Data
Downloading data from the datalogger…
Ideally, this is how it’s supposed to look…
Power Supplies Closed Path IRGAS Data Acquisition Computer Calibration Equipment Equipment Rack (later) Source: Dr. Larry Flanagan Nice and organized !
Other fieldwork related problems…
… turned out to be a ‘false’ Coral (phew!)
Still to come: CO 2 /H 2 O Analyzer Measures CO 2 and H 2 O fluxes using eddy covariance techniques Why ? To measure carbon balance