ISFS Sensor List

Standard ISFS sensors are available for the following measurements: momentum, sensible heat, and water vapor fluxes by eddy-correlation; vertical profiles of wind, temperature, and humidity; radiation fluxes; and soil temperature, soil moisture, and soil heat fluxes. The ISFS sensors are a mix of commercial instruments and in-house developments. Whenever possible, each sensor has a microprocessor that provides sensor output in calibrated engineering units through a serial communications link.

User-supplied or non-standard sensors can be readily accommodated by ISFS. Power and mounting are provided and the various data streams are easily integrated into the system.

The sensors are listed below:

Sensor Link Parameter Rate #
3-D sonic anemometer CSAT3 u,v,w - m/s; Tvs - deg C 60sps 21
3-D sonic anemometer CSAT3A u,v,w - m/s; Tvs - deg C 50sps 30
H2O/CO2 Open-path Gas Analyzer EC150 H2O/CO2 concentration 50sps 30
2-D sonic anemometer Wind Observer U, V - m/s 10sps 30
Temperature/Relative Humidity NCAR SHT85 in aspirated shield T - deg C; RH -% 1sps ~90
Nanobarometer 6000 Pressure - ub 13sps 30
Integrated Net Radiometer NR01 Global short/longwave in/out - W/m2 0.2sps 30
Pyranometer CM 21 Global shortwave radiation - W/m2 0.2sps 8
Pyranometer PSP Global shortwave radiation - W/m2 0.2sps 25?
Pyrgeometer CG4 Global longwave radiation - W/m2 0.2sps 6
Pyrgeometer PIR Global longwave radiation - W/m2 0.2sps 10
Soil temperature profile sensor NCAR Soil Probe Soil temperature - deg C 0.2sps 31
Heat flux plate HFT-3 Soil heat flux - W/m2 0.2sps 31
Soil moisture EC-5 Soil moisture - % vol 0.2sps 30
Soil moisture TRIME-FM w/P3 and T3 probes Soil moisture - % vol manual 1
Soil thermal properties TP01 conductivity, diffusivity, heat capacity 0.2sps 31
Precipitation/Present Weather Parsivel2 Equivalent water depth 1sps 30
Wetness Decagon Qualitative-can deduce type 0.2sps 30

Retired ISFS Sensors

Sensor Link Parameter Rate #
3-D sonic anemometer ATI-K u,v,w - m/s; Tvs - deg C 20sps 5
3-D sonic anemometer NCAR NUW u,v,w - m/s; Tvs - deg C 20sps 5
3-D sonic anemometer 1012R2A u,v,w - m/s; Tvs - deg C 21sps 1
1-D sonic anemometer ATI w - m/s; Tvs - deg C 20sps 2
Prop-vane anemometer 9101 U, V - m/s 5sps 11
H2O/CO2 Open-path Gas Analyzer LI-7500 H2O/CO2 concentration 20sps 5
IR H2O/CO2 analyzer (closed-path) 7000 H2O/CO2 concentration 20Hz 1
IR CO2 analyzer (closed path) 6251 density - gm/m3 10Hz 1
Infrared CO2 analyzer (closed path) DX6100 density - gm/m3 10Hz 1
Pressure sensor PTB100B Pressure - mb 1Hz 1+?
Pressure sensor PTB220B Pressure - mb 1Hz 9
Pressure sensor PTB210 Pressure - mb 1Hz 30
Hygrothermometer 50Y Humitter T - deg C; RH -% 1Hz 14
Dew Point   Dew point - deg C 1Hz 1?
Surface temperature sensor 4000.4ZL Surface temp. - deg K 1sps 10
Soil temperature sensor ?? Soil temperature - deg C 1Hz 12?
Soil moisture EC-20 Soil moisture - % vol 1Hz 10
Soil moisture CS-615 Soil moisture - % vol 1Hz ~10
Net Radiometer Q*7 Net radiation - W/m2 1Hz 19
PAR radiometer Quantum (LI-190SA) PAR radiation - W/m2 1Hz 6
precipitation NOAH II w/ Lexan wind screen Equivalent water depth - 0.01 inch events 3

Other sensors that we've used but do not have

Sensor Link Parameter Rate  
UV absorption hygrometer KH20 vapor density - gm/m3 60sps 12
Soil Temperature sensor CS107 soil temperature (C) 1Hz  
Soil Potential sensor CS229 soil moisture 1Hz  
Ultraviolet radiometer TUVR ultraviolet radiation - W/m2 1Hz 1
Rain gauge (Optical - ORG)   rainfall rate - mm/hr 1Hz 1
Snow depth gauge (Ultrasonic) SR50 snow depth - mm 1Hz 1
Dual beam ozone analyzer 49 O3 - ppb 1Hz 1
carbon monoxide analyzer 48 CO 1Hz 1
condensation nucleus counter 3760 CNC condensation nuclei 1Hz 1
precipitation Tipping bucket Equivalent water depth - 0.01 inch events 29

Flux measurements made by ISFS utilize the eddy-correlation technique. Momentum flux is determined from the covariance between the vertical and horizontal velocity fluctuations measured by the 3-dimensional sonic anemometers. Sensible heat flux is determined from the covariance between measured vertical velocity and temperature fluctuations. Latent heat and carbon dioxide flux is determined from the covariance between measured vertical velocity and humidity or carbon dioxide fluctuations.

Measurement of fluxes of trace chemical species are obtained from correlating fluctuations from chemical species sensors with those from the ISFS velocity sensors. ISFS has several varieties of CO2 sensors for this purpose. Other chemical species measurements require user-supplied sensors which typically can be readily interfaced to ISFS. In chemical flux determination, delay times through inlet tubes can be measured and compensated for in the processing.

Tilt corrections for the sonic anemometer are applied in the software. Over uniformly flat terrain, the tilt correction puts the anemometers into a coordinate system parallel to the surface. In complex terrain, signals from two-axis level sensors are used to orient the sonic anemometers to gravity. Note also that the sonic anemometers make a virtual temperature measurement, Tc, reported in degrees Celsius. We maintain software to remove the moisture contribution to Tc from the sensible heat flux computation based on colocated latent heat flux measurements.

Mean temperature and humidity measurements are made with a commercial solid-state temperature/relative humidity sensor in an aspirated radiation shield developed by us to operate at relatively low power.

Measurement of the surface energy balance is achieved using up-looking and down-looking pairs of short and long-wave radiometers (either individual component or in an integrated 4-component radiometer) in tandem with soil heat flux plates and soil temperature sensors. Soil heat capacity also is measured to complete the calculation of heat storage above the soil heat flux plates.