Trent Weather
Station (Lafleur)
Lethbridge Microclimate Station (Flanagan)

Coulee Weather
Station (1 of 6)
(Letts)

Cundinamarca,
Colombia

Pearce Corners Cottonwood Grove

Temperature Measurement
Thermocouple
•2 wires of different composition 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

Stevenson Shield
An earlier radiation shield often used with wet and dry bulb thermometers
Photo: Trent Weather Station

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.

Krypton Hygrometer
Source emits in the 121-
122 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

Rainfall and Snowfall Measurements
Precipitation Gauge with Nipher Shield

Tipping Bucket Raingauge
Cauca, Colombia
Each ‘tip’ is logged by the datalogger

Tipping
Bucket
Raingauge
Mechanism

‘Old-fashioned’ raingauge
Parque Munchique
Cauca, Colombia

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

Radiation Measurements
Shields made of materials appropriate for desired wavelength
(eg. polyethylene for net radiation – transparent to both longwave and shortwave energy)
Net radiometer
Millivolt signals are proportional to the radiation level

Pyranometer
Measures solar radiation on planar surface
Pyrgeometer
Measures infrared (longwave) radiation
UV-B Radiometer
Measures ultraviolet solar radiation on planar surface

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

2 º30 ´ 25 ´´ N, 77º00 ´ 02 ´´ W, 1450 m
Field Station
Tambito al
Cocal River
Photo taken from microclimate station

Downloading data from the datalogger…

Ideally, this is how it’s supposed to look…

Equipment Rack
Closed Path IRGAS
(CO2/H20 Analyzers)
Power Supplies
Calibration
Equipment
Source: Dr. Larry Flanagan
Data Acquisition Computer

“Leaf’ Wetness Sensor

Leaf Wetness Data
1
0, 9
Proportional
0, 8 leaf
0, 7 wetness
0, 6
0, 5
0, 4
0, 3
0, 2
0, 1
2.5 m etre s
5.0 m etre s
10 m etre s
0
0 2 4 6 8 10 12 14 16 18 20 22
1
Hour
0,9
Figure 5.11a
Average leaf wetness at 2.5, 5.0 and 10m height within the canopy of the Bosque station.
Proportional
0,8 leaf
0,7 wetness
0,6
0,5
0,4
0,3
0,2
2.5 metres
5.0 metres
10 metres
0,1
0
9 Aug
0
19 Aug
200
Day
400
29 Aug
600
7 Sept
Figure 5.11b
Complex pattern of leaf wetness at 2.5, 5.0 and 10m height within the canopy of the Bosque station.from August 9 to September 9, 1999.

Photosynthesis Measurement
Met stations often support ecological research projects

Leaf Reflectance
Measurement
(NDVI, CI, PRI, WBI)

Chlorophyll Fluorescence

Stemflow Measurements
(Rood)
Scaling leaf-level gasexchange to whole plant hydraulics in a riparian environment