Niwot Ridge is located approximately 35 km west of Boulder, Colorado, with the entire study site lying above 3000 m elevation. There is a cirque glacier (Arikaree Glacier), extensive alpine tundra, a variety of glacial landforms, glacial lakes and moraines, cirques and talus slopes, patterned ground, and permafrost. The research area is bounded on the west by the Continental Divide, with runoff on the two sides being destined for the Colorado and Mississippi Rivers. The alpine study area is reached by an unimproved road from the Mountain Research Station (2895 m) which leads to within 2 km of the main tundra research site, the Saddle (3528 m). The D-1 research site (3739 m), for which climate records are continuous from 1952, lies a farther 3 km from the road head. The Martinelli study area (3380 m) is located 1 km southwest of the Saddle, in the forest-tundra ecotone. The Green Lakes Valley lies immediately south of the western half of Niwot Ridge. It includes the Arikaree Glacier at its head (3798 m), and the wetland, Green Lake 4, and Albion research sites. The Green Lakes Valley and Martinelli sites are all within the City of Boulder Watershed which is closed to public access. Niwot Ridge, including the main alpine study site, is part of the Roosevelt National Forest and has been designated a Biosphere Reserve (United Nations Educational, Scientific and Cultural Organization, UNESCO) and an Experimental Ecology Reserve (USDA Forest Service). A context-sensitive topographic relief map can be used to access the scenic views of the areas indicated above, as well as several others.
C-1 is located in a Subalpine Forest, 9.7 km east of the Continental Divide. Topographic setting: ridge-top. Climate data completeness good from 1953 to present. Climate parameters measured include temperature, relative humidity, solar radiation, barometric pressure, wind speed and direction, precipitation, soil moisture and temperature, snow depth. At this site are also atmospheric and ecological research operations including the NCRS Snotel site, NOAA CMDL Carbon (CO2) and Halocarbon (anthroponenic greenhouse gases and staospheric ozone depletors, and surface ozone) measurements, National Weather Service precipitation gage, NOAA Climate Research Network (CRN) weather station, Ameriflux tower (forest ecology and atmospheric flux).