Does it Matter Where on the Summit we Measure Temperature and Humidity

Observers have measured temperature and humidity every day since 1932 using a sling psychrometer. The exact location these measurements are taken have changed over the years whenever the Observatory location changed. But does it matter for the fidelity of ourclimate record?

Interns Ben Charles and Austin Patrick took the first step toward answering this question. They sought to determine whether or not the variability of and average temperature and humidity during a 5-minute period at multiple locations were different between sites. To do so, they first needed to see if the mobile instrument they were using (a handheld Kestrel 4000) is accurate enough to use for this study. They compared measurements from the Kestrel 4000 to the calibrated instruments at the summitby placing the instruments side-by-side for 5-minutes at a time during different times of day and under variable weather conditions. They also comparedtemperature, humidity and wind speedmeasurements from two Kestrel 4000 instruments to determine whether the Kestrel 4000 is accurate and precise enough to use for this research project.

Ben and Patrick analyzed data collected over three weeks and concluded that the two Kestrel 4000 instruments and the methods of taking the observations resulted invalues withlarge average and variability differences that make it an inappropriate mobile instrument for this particular study.Some changes in the methods for taking the measurements may account for some of the differences and will be explored in future research.

Interns Ben Charles (left) and Austin Patrick (right) sling Kestrel 4000 instruments alongside Observer Ian Bailey (center) making an official hourly temperature and humidity observation with a sling psychrometer.