Air Temperature On Niwot Ridge
Air temperature data from the Niwot Ridge LTER show relatively rapid, directional change over the past 70+ years. To learn more, explore our long-term alpine and subalpine temperature records, visualized below.
Long-term Trends in Alpine and Subalpine Summer Air Temperature
The figure below visualizes yearly mean summer (July through September) air temperatures across the subalpine (red circles) and alpine (blue triangles) temperature records on Niwot Ridge.
Alpine Air Temperature Anomalies On Niwot Ridge by Year and By Season
The below figures visualize how yearly (left) and seasonal (right) air temperatures deviate from average temperatures across the Niwot Ridge alpine temperature record.
about Air Temperature Data from Niwot Ridge
Climate Stations:
The Niwot Ridge LTER collects and curates long-term air temperature records from climate stations above treeline in the alpine and below treeline in the subalpine. The subalpine climate station (C1, Figs. 1 and 2) is located on locally level terrain on the southeastern flank of Niwot Ridge, 6.0 miles (9.7 km) east of the Continental Divide. The elevation of the subalpine climate station is 9,915 ft (3,022 m), and the surrounding vegetation is closed-canopy subalpine conifer forest. The alpine climate station (D1, Figs. 1 and 3) is on a narrow, exposed ridge on the westernmost part of Niwot Ridge, 1.6 miles (2.6 km) east of the Continental Divide. At an elevation of 12,267 ft (3,739 m), this alpine station is the highest continuously operating weather station in North America. Surrounding vegetation is low-stature alpine trundra. While the Niwot Ridge LTER also collects long-term precipitation records at other sites (including from the Saddle, Fig. 1), the data visualized on this page are from the subalpine and alpine climate stations.
Figure 1: Climate stations of the Niwot Ridge LTER. Blue stars indicate the location of the subalpine (C1), Saddle, and alpine (D1) climate stations.
Figure 2: The subalpine (C1) climate station on Niwot Ridge.
Figure 3: The alpine (D1) climate station on Niwot Ridge.
Instrumentation and Data Collection:
Long-term air temperature records from Niwot’s alpine (D1) and subalpine (C1) stations exist from 1952-Present. Air temperature data are collected at both stations using analog chart-recording hygrothermographs housed inside a Stevenson screen (Figs. 4 and 5). The data shown in the figures on this page are mean values calculated from the chart-recording hygrothermograph (Fig. 5) after correcting for gaps in data collection.
Niwot collects air temperature data from other co-located instruments in at the subalpine (C1) climate station, and data from these instruments supplement the long-term air temperature record. For example, in 2000, Niwot began collecting air temperature and relative humidity at the subalpine climate station from a Campbell Scientific CS500 temperature and relative humidity probe. From 2000-2013, data from this probe was recorded by a CR23X data logger, which was replaced in 2013 by a CR10000 data logger. In the fall of 2016, triplicate HMP155A sensors (Fig. 5) which respond more rapidly to temperature fluctuations, were installed to replace the CS500 probes. In 2018, Niwot added aspirated air temperature reference sensors (Fig. 4) next to the Stevenson screen at the subalpine climate station. These sensors are the recommended method of measuring air temperature according to the World Meteorological Organization.
Figure 4: Meteorological instrumentation at the subalpine C1 climate station. The Stevenson screen is the white wooden box that houses the analog chart-recording hygrothermograph and the HMP sensors. The tower to the right of the screen collects aspirated air temperature at two heights. Photo by Gabriel de la Rosa.
Figure 5: Air-temperature instrumentation inside the Stevensen Screen at the subalpine C1 climate station. The long-term climate record is collected from the chart-recording hygrothermotraph (right side of image). The three HMP sensors (left side of image) are more recent additions that measure air temperature and humidity. The Stevensen screen is the white, wooden box in which these instruments are housed. Photo by Jen Morse.
How To Cite Data and Figures On this page
The Niwot Ridge LTER welcomes your use of the figures on this page when accompanied by the following citations:
Subalpine Temperature Data:
Kittel, T., C. White, M. Hartman, K. Chowanski, T. Ackerman, M. Williams, M. Losleben, and M. Moore. 2024. Infilled daily air temperature data for C1 chart recorder, 1952 - ongoing. ver 4. Environmental Data Initiative. https://doi.org/10.6073/pasta/8dfc895515c1b049fac72c0f7bea8830.
Alpine Temperature Data:
Kittel, T., C. White, M. Hartman, K. Chowanski, T. Ackerman, M. Williams, M. Losleben, and M. Moore. 2024. Infilled daily air temperature data for D1 chart recorder, 1952 - ongoing. ver 4. Environmental Data Initiative. https://doi.org/10.6073/pasta/3ba20e45e4a8831890999d42bd174b69.
Click on the above links to further explore Niwot Ridge air temperature data packages, which are hosted on the Environmental Data Initiative Data Portal. Data packages include detailed information about where and how our air temperature data is recorded and processed.
Contact Us
If you have questions about the data presented on this page, please email the Niwot Ridge LTER. To learn more about research, education, and outreach conducted by the Niwot Ridge LTER, please visit our website.