Validation of Glacier Mass Balance Modeling Using USGS Measurements  The PTAA model uses the bias-reduced MM5-down-scalings (daily maximum and minimum temperatures and precipitation) as inputs in combination with the area altitude distribution of Gulkana Glacier to simulate the Gulkana Glacier mass balances. At Gulkana Glacier, sustained negative mass balance has been associated with substantial area loss. Mass Balance Factsheet for the Gulkana Glacier, Alaska. During 1997-2001, Gulkana Glacier showed a continued and accelerated negative mass balance trend, especially below the equilibrium line altitude where thinning was pronounced. 3.2. Thus, the balance year beginning in September 2013 and ending in September 2014 is called “balance year 2014.” The trends of climate change indicate that glacier melt will continue to increase. Mass balance is typically calculated over a balance year, which begins at the onset of snow and ice accumulation. Mass balance, meteorology, area altitude distribution, glacier-surface altitude, ice motion, terminus position, and runoff at Gulkana Glacier, Alaska, 1996 Balance Year. Measurements began on South Cascade Glacier, WA in 1958, expanding to Gulkana and Wolverine glaciers, AK in 1966, and later Sperry Glacier, MT in 2005. Measurements began on South Cascade Glacier, WA in 1958, expanding to Gulkana and Wolverine glaciers, AK in 1966, and later Sperry Glacier, MT in 2005. Ice motion also slowed, which combined with the negative mass balance, resulted in glacier retreat under a warming climate. From 1980-2008 the mean cumulative mass loss of glaciers reporting mass balance to the World Glacier Monitoring Service is -12 m. This includes 19 consecutive years of negative mass balances. 4A) was relocated at 2,020-m altitude in the eastern cirque of Gulkana Glacier. USGS began biannual measurements of glacier mass balance and meteorology at Alaska's Wolverine and Gulkana glaciers in … (Liljedahl et al., 2017). of the Gulkana Glacier (from USGS database) Balance Year Winter Balance Summer Balance Net Balance 1966 0.93 1.03 -0.1 2Methods 2.1 Site description The USGS began consistent measurements of glacier mass balance, streamflow and meteo-rology at Gulkana and Wolverine glaciers in 1966. It is a polythermal glacier (Miner et al., 2018), and the mean annual mass balance during 2011–2016 was −1.6 m w. eq. Analyse the Glacier Mass Balance Over the whole time period, is the average annual mass balance (Ba) positive or negative? 3 1. Explaining mass balance and retreat dichotomies at Taku and Lemon Creek Glaciers, Alaska. Gulkana Glacier is located on the south side of the Alaska Range about 10 miles north of Paxson, along the Richardson Highway. It is imperative that we understand and quantify how this will affect freshwater river runoff and downstream hydrology in order to better inform local response, policy, and resource management.  A glacier with a sustained negative balance is out of equilibrium and will retreat, while one with a sustained positive balance is out of equilibrium and will advance. These glaciers have the longest continuous mass-balance records in North America, with winter balance Bw, summer balance Bs, and annual balance … Under the following links you find more information about the reference glaciers, the mass-balance datasets, and detailed assessments of global glacier mass changes.. 2 Mass balance data. Since the late 1950s, the USGS has maintained a long-term glacier mass-balance program at three North American glaciers. In 2005, Sperry Glacier in Montana was added to the program, allowing changes in glacier mass in the principal North American climate zones to be tracked. 2b, c) with the most notable episode occurring in the late 1970s. annual balance was -2.04 m. Gulkana Glacier (lat 63'15' N., 1,700-m mean equilibrium line altitude) had a winter balance of 1.05 m, approximately normal for this glacier; the final annual balance was -0.30 m. INTRODUCTION The purpose of the International Hydrological Decade (1965-74) is to increase the understanding and to promote In 2005, Sperry Glacier in Montana was added to the program, allowing changes in glacier mass in the principal North American climate zones to be tracked. Over the 1946–2018 period, the cumulative mass balances diverged. The Jarvis Glacier is located north of the Gulkana Glacier; a drilling project was conducted on the glacier in April 2017 (Miner et al., 2018). Since the late 1950s, the USGS has maintained a long-term glacier mass-balance program at three North American glaciers. change from digital date, west gulkana glacier, alaska l. sam thompson and stephen e. smith ..... 11 determination of 1957-1986 mass balance of west gulkana glacier, alaska, by comparison of topographic maps fred b. chambers ..... 19 two-year mass balance of west gulkana glacier, alaska We reanalyzed mass balance records at Taku and Lemon Creek Glaciers to better understand the relative roles of hypsometry, local climate and dynamics as mass balance drivers. We derive historic ELA sensitivities to climate forcing using data from the U.S. Geological Survey (USGS) Benchmark Glacier program. [Rod March; Geological Survey (U.S.)] This article summarizes the findings of this survey and reports on the inferences that the data permit for three decades of regional climate. team of scientists remapped West Gulkana Glacier and determined its mass-balance changes. For example, the balance year at Gulkana Glacier starts and ends in September of each year. ciers: Wolverine Glacier in Alaska’s Kenai Range, Gulkana Glacier in the Alaska Range, and South Cas-cade Glacier in Washington State’s Cascade Range (Fig. S. O'Neel is acknowledged for providing the Gulkana Glacier mass balances, M. Huss for the Black Rapids ice thicknesses, and A. Arendt for computational resources and funding. The “mass balance” of the Gulkana has been calculated at different times in an ongoing study about the effects of our dependence on fossil fuels and the related global warming crisis. Results from South Cascade Glacier in Washington and Gulkana and Wolverine glaciers in Alaska provide the longest continuous record of North American glacier mass balance. Direct field measurements are combined with weather data and imagery analyses to estimate the seasonal and annual mass balance at each glacier in both a conventional and reference surface format (Cogley and … This map is of the same glacier depicted in the photos attached later in the lesson. The net mass balance on Gulkana Glacier, Alaska, U.S.A., has been measured since 1966 by the glaciological method, in which seasonal balances are measured at three index sites and extrapolated over large areas of the glacier. The Gulkana Glacier is one of three benchmark glaciers in the United States that the US Geological Survey have been monitoring since 1971. Alaska Table 1. Examine the map of net mass balance for South Cascade Glacier in 1965. Get this from a library! Negative values indicate a net loss of ice and snow compared with the base year. Mass balance (m w. water balance of Gulkana and Woverine Glaciers, Alaska, and South Cascade Glacier, Washington, 1965 and 1966 water years. Vertical photographs were taken on August 31, 1967, by Austin Post and were used to redefine the margin of Gulkana Glacier and other glaciers and perennial snow fields in the basin. This figure shows the cumulative mass balance of the three U.S. Geological Survey “benchmark” glaciers since measurements began in the 1950s or 1960s. eq.) Systematic errors can accumulate linearly with time in this method. Episodes of positive glacier-wide mass balance (greater than uncertainty) have modulated mass loss at Wolverine Glacier several times since the observations began (Fig. C. K. Echelmeyer, M. Stuefer, and R. Flanders were instrumental in maintaining the mass balance program on Black Rapids Glacier during the 1990s and 2000s. 1). Since the late 1950s, USGS has maintained a long-term glacier mass-balance program at three North American glaciers. Glacier mass balance is the direct and non delayed response against the climate change and hence it is one of the essential variables require to monitor the climate system. The net mass balance on Gulkana Glacier has been measured since 1966 by the glaciologi-cal method, in which seasonal balances are measured at three index sites and extrapolated over large areas of the glacier. Similar measurements began at Sperry Glacier, MT in 2005. Tuesday, August 3, 2010. Systematic errors can accumulate linearly with time in this method.