Elevation Range: Approximately 450-1680 meters
Location: Latitude: 60°25'15.64"N, Longitude: 148°51'34.89"W
Area: 16.2 km2
Wolverine Glacier is in the Kenai Mountains on the coast of south-central Alaska. The climate is maritime, characterized by low temperature variability and heavy, regular precipitation. Wolverine Glacier has a southerly aspect, with a narrow terminus at 450 m and a broad head up to 1680 m. In 2011 the Glacier was approximately 7 km long, and encompassed an area of 16.2 km2 in its 24.5 km2 basin (Van Beusekom and others, 2010).
In 1966 scientists with the USGS began making direct measurements of surface mass balance at Wolverine Glacier, one of two "benchmark glaciers" in Alaska. Repeated measurements at three long-term "index" sites, in conjunction with local meteorology and runoff data, are used to estimate glacier-wide mass balances. These data constitute the longest continuous set of mass-balance data in North America (Josberger and others, 2007) which are used to understand glacier dynamics and hydrology, and to understand the glacier's response to climate change.
In 1966 the U.S. Geological Survey began direct measurements of surface mass balance at Wolverine Glacier (Mayo et al, 2003). After a decade of dense spatial sampling the measurements were reduced to three "index" sites distributed across the elevation range of the Glacier. Field visits to measure and maintain stakes at the three index sites are made each spring, at the onset of the melt season, and again in early autumn, near its completion. Density of the material gained or lost is measured with a snow-pit or core. By collecting data near the balance maxima and minima direct measurements closely reflect maximum winter snow accumulation and the annual balances at each location. Since 1975 both the stakes and the glacier surface elevations at the actual index sites have been surveyed to allow calculations of velocity and surface elevation change.
Meteorological observations began in 1967 with installation of temperature and precipitation instruments. Today the stations are telemetered, and near real-time values of temperature (with both passive and actively ventilated shields), relative humidity, year-round precipitation (with known compromises in measuring snow), wind speed and direction, and solar radiation are publicly available. Recent changes to the program include installing modern precipitation gauges (Sutron) and installing new stations to directly measure lapse rates in each basin.
Current data available from the Wolverine weather station (USGS 15236895) includes:
- Temperature, air
- Wind speed
- Wind direction
- Cumulative Precipitation
Instrument Site and Climate Description
The Wolverine weather station (60°23' N, 148°55' W) is located at an altitude of 990 meters (m) on a tundra knoll along the western boundary of the basin. The station is slightly lower than the glacier's average equilibrium line altitude and approximately 500 m from the west edge of the glacier. The average annual air temperature at the recorder site is about -1.0 degree Celsius(°C), and the average annual precipitation-gage catch is about 1,100 millimeters (mm) (recorded annual precipitation catch represents approximately 33 percent of actual annual basin precipitation due to the low catch efficiency for snowfall). Snowfall is the dominant form of precipitation and usually accumulates on the glacier from September through mid-June. Daily average temperatures range from a low of -25°C to a high of 15°C. Daily precipitation catch can be over 110 mm.
The original weather station had analogue instruments with strip-chart recorders. Daily average temperatures from that era have an accuracy of about ±1.0°C (Mayo, March, and Trabant, 1992; Kennedy, 1995). Daily precipitation records are complicated by thermal expansion of the antifreeze water solution. The annual precipitation record represents approximately 33 percent of actual annual basin precipitation due to limited catch efficiency during snowfall (Mayo and others, 1992). Starting in the late 1980's the station has been updated with progressively newer, more accurate, and more sensors.
Ridge-Top climate station
An additional weather station was installed at higher elevation in 2012. The ridge-top weather station (60°24' N, 148°57' W) is ~1 km west of the glacier at 1420 m. Measurements at this site include:
- Temperature (daily values available online)
- Relative Humidity
- Wind Speed
- Wind Direction
- Radiation ( incoming & outgoing, shortwave & longwave)
The "Wolverine Creek near Lawing" stream-gaging station, USGS station 15236900, is part of the USGS network of nearly 100 stations in Alaska. Data collection and analysis are conducted by standard techniques developed by the USGS. Daily values of discharge are available online and reported in annual publications of the USGS Water-Data Report series.
- Temperature, air
- Stream Discharge
- Gage height
Location: Latitude 60°22'14"N., Longitude 148°53'48"W., 370 m altitude, in NE 1/4 sec.10, T.3 N., R.3 E., Hydrologic Unit 19020202, on left bank about 0.15 km downstream from terminus of Wolverine Glacier and 25 km east of Lawing, Alaska.
Drainage area: 24.5 km2
Period of record: October 1966 to September 1978, October 1980 to September 1981, May 1997 to September 1997, October 2000 to current.
NOTE: Records are poor. The creek bed is composed of poorly-sorted gravel and small boulders. The channel is subject to frequent changes during high flows. Large fluctuations from ice melt and alternative damming and storage release during the melt season.
Typical summer mean daily discharge is about 9 m3/s; the period-of-record instantaneous peak discharge was 51 m3/s on August 21, 1981 (Benson and others, 1998).
Measurements began on Wolverine Glacier in 1966 resulting in many reports and analysis among other benchmark glaciers. Detailed results from 1966 and 1967 are reported by Meier and others (1971) and Tangborn and others (1977), respectively. Ice and water balances for 1965/66 hydrologic years are reported by Meier et al. (1971). Measured winter snow balances and annual balances from 1966-77 are reported by Meier and others (1980).
Since 1966, part of the Wolverine data set (net balance, accumulation, ablation, accumulation area ratio (AAR), and equilibrium line altitude (ELA)) has been published by the World Glacier Monitoring Service (Kasser, 1967; Muller, 1977; Haeberli, 1985; Haeberli and Müller, 1988; Haeberli and Hoelzle, 1993). Air temperature and precipitation data for 1967-1988 were published by Mayo, March and Trabant (1992) and summarized by Mayo and March (1990) and for 1994 by March (1998).