Climate

A windy and harsh environment

Measuring Climate

Meterological Tower that houses the TundraCam and many other instruments. The Tundra Lab lies just off the image to the right. Photo: Mark Losleben.

The TundraCam is mounted on a weather tower on a shallow saddle 5.5 kilometers (3.5 miles) from the Continental Divide. Scientists have been collecting climate data from a network of weather stations at various elevations on Niwot Ridge for more than 50 years, making it one of the longest-running records in North America. Instruments mounted near the camera measure air temperature, humidity, precipitation, solar radiation, wind speed and direction, and barometric pressure. The camera helps monitor weather conditions, snow drifting, and snowmelt patterns. Nearby equipment measures quantities of various atmospheric gases, such as carbon dioxide and surface ozone. All this data is part of the climate record.

Weather vs. Climate

Routine winter measurements being made at the D-2 meteorological station (3743 m) on Niwot Ridge (Colorado). Shoshone Peak (3952 m) is in the background at right (photo circa 1953). Photo: John Marr

Weather is comprised of meteorological conditions at a particular time and place. Climate, on the other hand, is the overall pattern of weather for a place, including average weather from year to year and the anomalies and variability in those patterns. Climate largely determines the distribution of plants and animals, influences water supplies, and affects human life as well. Studying climate helps us understand what to expect over the long term.

Temperature at the Saddle

Tundra Lab in the saddle of Niwot Ridge. View looking southeast. CC Meeting 2002. Photo: David Foster.

Because of its location on the high-altitude tundra, Niwot Ridge generally has colder temperatures, more solar radiation, more intense winds, and a shorter growing season than nearby lower elevations. Annual mean temperature at the Saddle site, where the TundraCam is located, is -2.2 degrees Celsius (28 degrees F). The January mean temperature is -13.2 degrees Celsius (8 degrees F) and the July mean is 8.2 degrees Celsius (47 degrees F). In contrast, the annual mean temperature in Boulder, only 27 km (17 miles) to the east, is +10.8 degrees Celsius (51.5 degrees F). Boulder's January mean temperature is 0.3 degrees Celsius (32.6 degrees F) and the July mean is 22.8 degrees Celsius (73 degrees F).

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Precipitation at the Saddle

Mark Losleben services a precipitation gauge. Photo: Mark Losleben.

Mean annual precipitation is about 930 mm (36 inches), of which one-third is used in evapotranspiration, the remainder leaving the system as runoff. Precipitation is highly variable throughout the year: about 80 percent occurs as snow during winter and spring months and annual totals vary greatly from year to year. The interactions among wind, snow, and complex terrain result in a mosaic of snow-free and snow-covered areas. Consequently there is wide variability in the amount and timing of the brief, intense meltwater release in late spring. Summer precipitation is also highly variable, both temporally and spatially, usually arriving in brief convective storms.

Research

Dan Carlson, Jacques Hueber and Florence Bocquet (all INSTAAR) after visiting two snowpack field sites in the Niwot Ridge LTER area, near Ward Colorado, January 2005. INSTAAR's Atmospheric Research Lab is investigating gas transfer through the snowpack by drawing and analyzing air from several depths. Photo: D. Helmig (INSTAAR).

Scientists are looking at many aspects of climate using the data from Niwot Ridge. Because most of the water supplies (Watershed) of the American West originate in mountain snowpacks, which are highly susceptible to the effects of global climate change, scientists continue to monitor long-term climate from Niwot Ridge and study snowpack deposition and composition. Nitrogen enrichment studies are being conducted to understand the changes that enhanced atmospheric deposition of nitrogen from air pollution will bring to the region. The National Oceanic and Atmospheric Administration (NOAA) provides support for monitoring atmospheric levels of greenhouse gases and ozone depletors such as carbon dioxide, methane, hydrogen, chlorofluorocarbons, carbon tetrachloride, methyl chloroform, and nitrous oxide. These measurements are part of a global network of air measurement sites in remote locations, monitoring the composition of the atmosphere. Weekly samples are collected to measure the acidity and chemical composition of precipitation as part of a U.S. network of more than 200 sites. Data from the Mountain Climate Program, which encompasses the network of weather stations on Niwot Ridge, is available as part of the Niwot Ridge LTER Data Catalog.

 

Weather on the Ridge

Clouds over Green Lakes Valley during the Spring, 2005 Snow Survey, Niwot Ridge LTER. Photo: Kurt Chowanski.

 

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