A JFSP Fire Science Exchange Network
Bringing People Together & Sharing Knowledge in the Northern Rockies

Comparison of sling psychrometer to digital weather meters

Date: April 22, 2015
Presenter(s): Charles W. McHugh
Description: Belt weather kits for recording of weather information have been in use since 1959. The use of a sling psychrometer from these kits is standard practice for the recording of dry and wet bulb temperatures to calculate relative humidity. Electronic based meters for recording weather information could replace belt weather kits for the recording of this information, streamlining the process and eliminate many of the errors often associated with the use of the sling psychrometer. However, anecdotal evidence from fire managers suggest relative humidity values of 5-20% lower from electronic meters compared to a sling psychrometer. Thus contributing to a disbelief and lack of confidence in the data these electronic meters provide field personnel. We will present preliminary results of a two phase study currently in progress comparing measured temperature and relative humidity values from electronic meters -such as the Kestral- to measured values of temperature and calculated relative humidity using a sling psychrometer. All measurements are taken in an environmental chamber at specific combinations of temperature and relative humidity. This study comparing values from the two types of measuring devices in a controlled environment is the first that we are aware of. 
Topic(s): Fire Behavior, Weather
Ecosystem(s): None
Type: Webinar
NRFSN number: 13774
Record updated: Apr 20, 2017