4000.4ZL

Infrared surface temperature sensor, with dial to set emissivity.  ISFS collects data from these with emiissivity set to 1, but selectable in our R-based data processing code.  The relatively small solid angle viewed by this sensor allows a target to be measured, rather than the entire hemisphere measured by downward-looking pyrgeometers.  ISFS has 10 with front-end PIC-based microprocessors to digitize the signal, but some now appear not to function.  We have considered purchasing replacements either from Everest or Apogee.