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 | 29 |
| H2O/CO2 Open-path Gas Analyzer | EC150 | H2O/CO2 concentration | 50sps | 24 |
| 2-D sonic anemometer | Wind Observer | U, V - m/s | 10sps | 30 |
| Temperature/Relative Humidity | NCAR SHT75 | T - deg C; RH -% | 1sps | ~90 |
| Pressure sensor | PTB220B | Pressure - mb | 1sps | 9 |
| Pressure sensor | PTB210 | Pressure - mb | 1sps | 18 |
| Nanobarometer | 6000 | Pressure - ub | 13sps | 6 |
| Integrated Net Radiometer | NR01 | Global short/longwave in/out - W/m2 | 0.2sps | 28 |
| 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 |
| Surface temperature sensor | 4000.4ZL | Surface temp. - deg K | 1sps | 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 | 10 |
| Precipitation | NOAH II w/ Lexan wind screen | Equivalent water depth - 0.01 inch | events | 3 |
| Precipitation | Tipping bucket | Equivalent water depth - 0.01 inch | events | 29 |
| 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 |
| UV absorption hygrometer | KH20 | vapor density - gm/m3 | 60sps | 12 |
| 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+? |
| Hygrothermometer | 50Y Humitter | T - deg C; RH -% | 1Hz | 14 |
| Dew Point | Dew point - deg C | 1Hz | 1? | |
| 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 |
Other sensors that we've used but do not have
| Sensor | Link | Parameter | Rate | |
| 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 |
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 flux is determined from the covariance between measured vertical velocity and humidity 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 specie measurement requires 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, Tvs, reported in degrees Celsius.
Mean temperature and humidity measurements are made with a hygrothermometer developed at NCAR and previously used with the NCAR Portable Automated Mesonet (PAM). These hygrothermometers are integrated sensors which utilize a platinum resistance thermometer and solid state relative humidity sensor inside an aspirated radiation shield enclosure.
Wind profiles are measured with commercial propeller-vane wind sensors which have been modified at NCAR to obtain a high resolution vane azimuth using an optical encoder. These sensors have also been modified to output a serial data string giving output in either windspeed and direction or orthogonal components.
Measurement of the surface energy balance is achieved using up-looking and down-looking pairs of short and long-wave radiometers in tandem with soil heat flux plates and soil temperature sensors. The chemical environment around ISFF sites can be monitored with sensors which measure ozone, carbon monoxide, as well as condensation nuclei.
