Climatological data were collected from the saddle climate station on Niwot Ridge (3525 m elevation) throughout the year. From 2000-06-24 to 2012-03-24, data were recorded using a Campbell Instruments CR23X data logger. Subsequently, data were recorded using a Campbell Instruments CR1000 data logger. This data set includes data beginning in 2009. Maximum and minimum values were recorded instantaneously, with a sampling interval of 5 seconds. Hourly means and totals were calculated from 720 individual measurements. The CR23X logger was programmed to generate both hourly and daily output. The CR1000 logger generated daily, hourly, and minute data until September 2014, and 10 minute and minute data thereafter. This dataset discontinued, see methods for instructions on accessing the 10 minute data instead.

This is a summary of major ion concentrations for stream water samples collected at the outflow of the Saddle stream, near Saddle grid point 007 on Niwot Ridge.

This is a summary of major ion concentrations for lake water at selected depths as well as for the inlets and outlets of Green Lakes 1, 4, and Lake Albion. On some occasions the same samples were also taken from other lakes in the Green Lakes Valley, such as Green Lakes 2, 3 and 5.

This dataset contains temperature data from two Onset HOBO temperature pendant loggers installed in Green Lake 4’s inlet and outlet from summer 2019. High-resolution water quality data are fundamental to observing rapid ecological responses to meteorology, climate, and other disturbance events. The inlet and outlet temperature data collected here, together with Niwot Ridge’s buoy deployed in Green Lake 4, allow us to understand lake hydrology, water budget, and stratification and mixing dynamics that drive seasonal in-lake processes to understand effects of warming.

Temperature data were collected on a daily time-scale from the C1 climate station (3018 m) since 1952. Over time various circumstances have led to days with missing values. Some missing values were estimated from redundant sensors and nearby climate stations using various methods. Greenland 1987 was a basis for the methodology. However when it was not possible to use this methodology, new methods were developed.

Precipitation data were collected on a daily time-scale from the C1 climate station (3018 m) since 1952. Over time various circumstances have led to days with missing values. Some of these values were estimated from nearby climate stations.

Pikas are captured, anesthetized, marked with colored ear-tags, non-lethally sampled, and released at point of capture during June-October. Study sites include a gradient of elevation and slope aspect, allowing a comparative study of pika response to variation in climate and sub-surface microclimate. Daily variation in snow cover and sub-surface temperatures are measured using data loggers placed within the territories of marked pikas. Focal territories are revisited at least once to characterize available vegetation via transect sampling and at least annually to service data loggers and record pika survival. Samples collected for genetic and physiological studies include ectoparasites, blood, saliva, urine, feces and hair as well as records of sex, stage, reproductive status, weight, foot length and body temperature.

Temperature data were collected on a daily time-scale from the D1 climate station (3743 m) since 1952. Over time, various circumstances have led to days with missing values. Some missing values were estimated from redundant sensors and nearby climate stations using various methods. Greenland 1987 was a basis for the methodology. However when it was not possible to use this methodology, new methods were developed.

Images from time-lapse cameras were analyzed to track the greenness curves of 16 plots in the Sensor Network at Niwot Ridge. Images were taken every 30 minutes during daylight hours throughout the growing season. Cameras were angled to view 1m^2 vegetation plots located at each sensor node. Pixels in the portion of the image capturing the vegetation plot were used to calculate the green chromatic coordinate (GCC). The change in GCC over the growing season represents the growth and phenology of the plant communities captured.

Thickness of seasonal ice cover in high alpine lakes can be influenced by local environmental change, including changes in temperature and winter precipitation. Increased winter precipitation can increase the insulating effects of snow cover on lake surfaces or increase water storage in the lake’s catchment, both of which may decrease ice thickness (Caine 2002). To assess long-term trends in seasonal ice thickness, as well as sensitivity to environmental drivers, measurements of ice thickness are taken approximately monthly throughout the winter at Green Lake 4.