Project Archives What's New Sensors Variables PI Interaction Online Documentation

NOTE: This WWW page is being phased out. Please go to our NEW ISFS WWW site for the latest information on the Integrated Surface Flux System.

1. ISFF Description

The Integrated Surface Flux Facility (ISFF) is designed to study exchange processes between the atmosphere and Earth's surface. This includes the direct measurement of fluxes of momentum, sensible and latent heat, trace gases, and radiation as well as standard atmospheric and surface variables. With multiple sensors and data systems, measurements of horizontal and vertical gradients also can be made. This facility, formed by integrating [formerly] ATD's former Atmosphere Surface Turbulent Exchange Research facility (ASTER) and Portable Automated Mesonet (PAM III and Flux PAM) facilities, is quite flexible and has been used in Arctic to desert conditions with sensor spacings from 1 m to 60 km (and separations of 1000s of km are possible). Average statistics of all variables, including the second-order moments needed to compute fluxes, are a standard product of ISFF and are available in real-time for display. When possible, every data sample is archived to allow processing using spectral, wavelet, or conditional sampling methods. ISFF also supports the addition of user-supplied sensors with digital or analog outputs at data rates up to 10,000 samples/s. The ISFF is managed by EOL/ISF (formerly ATD/RTF).

2. Project Archives

ISFF Project Documentation is available online for most projects. For each project listed there is a link to the project report, table of variables, field logbook, data links, and a contact person.

The project reports contain a description of the field site, instrumentation configuration, and data processing steps. For some projects, there are also plots of weather conditions, fluxes, etc.

The field logbook has all information logged by ISF staff and visitors before, during, and after the field campaign. Each entry is indexed by time, location, type (e.g. sensor), and author.

Data available online include 5-minute average statistics (through 4th-order moments for turbulence variables) of all quantities measured. For some projects, "raw" time series of every sample from each sensor also are available. These are processed using the calibrations that are current at the time of download -- users are encouraged to check with SSSF for the status of these calibrations.

3. What's New

ISF regularly upgrades sensors and components of the ISFF facility as new hardware and software capabilities become available and which are appropriate to our mission. Beginning in 2004, a New Data System is being developed that will retain all functionality while expanding computing and processing capacity with reduced power consumption over the previously utilized VME based components. The new system is based upon inexpensive, commercially available PC104 hardware; while operational software has been migrated to run under real-time Linux operating system.

To expand spacial coverage and mobility a new Adaptive Sensor Array approach is being pursued. This concept is based upon the emerging mesh-network techniques being developed at several educational institutions, NCAR and commercial companies. See the Adaptive Sensor Array Power Point Presentation that ISF provided for NSF which outlines this effort and the first deployment of our new data system.

4. Sensors

Standard ISFF 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 ISFF 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 ISFF. Power and mounting are provided and the various data streams are easily integrated into the system.

Below is a listing of the most common ISFF sensors. Documentation on all ISFF sensors is available.

Sensor Manufacturer Model Parameter Rate #
3-D sonic anemometer CSI CSAT3 u,v,w - m/s; Tvs - deg C 60sps 21
UV absorption hygrometer CSI KH20 vapor density - gm/m3 20Hz 12
H2O/CO2 Open-path Gas Analyzer LI-COR LI-7500 H2O/CO2 concentration 20sps 5
Prop-vane anemometer NCAR/SSSF - R.M. Young   U, V - m/s 5Hz 7?
Prop-vane anemometer R.M. Young 9101 U, V - m/s 5Hz ~10
Hygrothermometer NCAR/SSSF - Vaisala 50Y Humitter T - deg C; RH -% 1Hz 14?
Pressure sensor Vaisala PTB220B Pressure - mb 1Hz 9?
Net Radiometer REBS Q*7 Net radiation - W/m2 1Hz 19
Pyranometer Kipp & Zonen CM 21 Global shortwave radiation - W/m2 1Hz 8
Pyranometer Eppley PSP Global shortwave radiation - W/m2 1Hz 25?
Pyrgeometer Kipp & Zonen CG4 Global longwave radiation - W/m2 1Hz 6
Pyrgeometer Eppley PIR Global longwave radiation - W/m2 1Hz 10
Soil temperature sensor REBS   Soil temperature - deg C 1Hz >10
Heat flux plate REBS HFT-3 Soil heat flux - W/m2 1Hz >10
Soil moisture Decagon Ech2o Soil moisture - % vol 1Hz 10
Soil thermal properties Hukseflux TP01 conductivity, diffusivity, heat capacity 1Hz 9
Surface temperature sensor Everest Interscience 4000.4ZL Surface temp. - deg C 1Hz 10

5. Variable Names

Since many different variables can be measured at multiple sites, a naming convention, ISFF Variable Names, has been established to manage the profusion of variable names.

6. PI Interaction

We encourage our users to be involved with all aspects of the field measurements. To this end, we have a User Guide to describe all of the aspects of our field deployments.

7. Additional Online Documentation

PAM Station Information and References
Wind Direction Quick Reference
Sonic Anemometer Tilt Correction
Corrections to Sensible and Latent Heat Flux Measurements
Calculation of Roughness Length and Zero-Plane Displacement
Calculation of Long-Wave Radiation
ASTER Field Reference
Description of analysis software ("dat" under S+ or R)
Averaging 5-minute statistics over longer periods
Quick guide to high-rate data analysis using S+
Site Requirements for the ISFS Base and Towers
ISF Calibration Laboratory (used for most temperature/humidity/pressure sensors)
Doxygen documentation of NIDAS (NCAR In-Situ Data Acquistion Software)
Documentation of TRAM system

Gordon Maclean

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