Climate data for D1 chart recorder, 1982 - 1988.

Climatological data were collected from a Niwot Ridge climate station (D1 at 3743 m) throughout the year. Parameters measured were temperature, relative humidity, solar radiation, wind speed and run of wind. The station was instrumented with a thermohygrograph (regularly calibrated and checked with maximum and minimum thermometers and psychrometers), which was equipped with a Bourdon tube (to measure temperature) and a banjo-spread hair element (to measure relative humidity). The thermohygrograph was situated in a white, all wood, louvered Stevenson screen which was oriented with the door facing north. Solar radiation was recorded on a bimetalic strip mechanical actinometer. Ninety percent of solar radiation from 360 to 2000 nm was transmitted through the instrument's glass dome. Wind speed (peak gust) was measured with a 3-cup, AC-generating anemometer that continuously recorded onto an Esterline Angus strip chart recorder. Run of wind was measured with a Belford totalizing cup anenometer with a counter (at a height of approximately 3 meters above ground). Average wind speed was calculated from the peak gust trace. The thermohygrograph and actinometer both used wind-up or battery-driven clock drives that rotated the recording chart on a right cylindrical drum with a fixed period between 24 h and 861 h depending on the gears used. These clock mechanisms were virtually identical and therefore completely interchangeable among the instruments.