D-1 (3743 m) climate station: Precipitation data.

Precipitation data were collected from an upper Niwot Ridge climate station (D-1 @ 3743 m) throughout the year using a chart recorder. The station was initially instrumented with a standard 8-inch precipitation gauge installed with the rim 1 m above ground. Measurements were made on an approximately weekly basis. This gauge was not shielded prior to October 1964. A recording precipitation gauge was installed at the beginning of January 1965. Precipitation was caught in a bucket containing ethylene glycol (to melt snow) and light oil (to prevent evaporation). As the weight of the bucket increased, a pen moved up via a spring mechanism and recorded on a rotating chart. An Alter shield and snow fence were placed around the gauge to give more accurate precipitation measurements during windy conditions. Precipitation was recorded on a continuous basis