Radiation and Cloud Observations on a High Arctic Plateau Ice Cap

Bradley, Raymond S.

doi:10.1017/s0022143000008649

Cited by 29 publications

(6 citation statements)

References 19 publications

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“…On average R net = 7.3 Wm −2 during overcast and R net = 15.7 Wm −2 during clear-sky conditions, despite the obvious and pronounced reducing effect on incoming shortwave radiation: SW i = 56.1 Wm −2 and SW i = 236.0 Wm −2 for overcast and clear-sky conditions, respectively. This is due to the generally high albedo which reduces the relative importance of net shortwave radiation in the radiation budget (Ambach 1974;Serreze and Bradley, 1987).…”

Section: Concluding Discussionmentioning

confidence: 99%

Meteorological conditions on an Arctic ice cap—8 years of automatic weather station data from Austfonna, Svalbard

Schuler

Dunse

Østby

et al. 2013

Intl Journal of Climatology

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Only few reliable records are available covering more than 5 years of meteorological conditions on Arctic glaciers. Here, we report on the operation of an automatic weather station at the Austfonna ice cap, Svalbard, over an 8-year period from 2004 to 2012. Time series of measured and derived quantities are analysed to characterize meteorological conditions close to the equilibrium line altitude at ∼400 m.a.s.l. The mean annual temperature is −8.3 • C but exhibits large variability such that excursions above 0 • C occur even during winter. In general, relative air humidity is high and evaluating the wind pattern, we find that moisture is primarily advected from south-easterly directions. Net radiation is dominated by shortwave radiation and, hence, surface albedo plays an important role in the radiation budget. Frequent summer snowfalls, as observed in 2008, have the ability to maintain a high albedo over much of the ablation season, thereby having large impact on the energy balance as well as on glacier mass balance. Cloudiness is assessed using records of incoming longwave radiation. Analyzing the radiation data, we find evidence for the radiation paradox, i.e. an increase of average net radiation (2004-2012) from −15.7 W m −2 for clear-sky conditions to 7.3 W m −2 during overcast skies.

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Section: Concluding Discussionmentioning

confidence: 99%

Meteorological conditions on an Arctic ice cap—8 years of automatic weather station data from Austfonna, Svalbard

Schuler

Dunse

Østby

et al. 2013

Intl Journal of Climatology

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“…The top of the atmosphere radiation, R TOA , is modified by the observed sea ice concentration, C SeaIce , and a factor to account for absorption of incoming radiation by clouds, A cloud . This factor incorporates the seasonal cloud fraction, CF [Dong et al, 2010], and average transmission of incoming radiation by clouds, f cloud (Serreze and Bradley [1987], taken as 0.5). This results in the following:…”

Section: 1002/2013jf002845mentioning

confidence: 99%

Modeling erosion of ice-rich permafrost bluffs along the Alaskan Beaufort Sea coast

Barnhart

Anderson

Overeem

et al. 2014

J. Geophys. Res. Earth Surf.

145

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The Arctic climate is changing, inducing accelerating retreat of ice‐rich permafrost coastal bluffs. Along Alaska's Beaufort Sea coast, erosion rates have increased roughly threefold from 6.8 to 19 m yr−1 since 1955 while the sea ice‐free season has increased roughly twofold from 45 to 100 days since 1979. We develop a numerical model of bluff retreat to assess the relative roles of the length of sea ice‐free season, sea level, water temperature, nearshore wavefield, and permafrost temperature in controlling erosion rates in this setting. The model captures the processes of erosion observed in short‐term monitoring experiments along the Beaufort Sea coast, including evolution of melt notches, topple of ice wedge‐bounded blocks, and degradation of these blocks. Model results agree with time‐lapse imagery of bluff evolution and time series of ocean‐based instrumentation. Erosion is highly episodic with 40% of erosion is accomplished during less than 5% of the sea ice‐free season. Among the formulations of the submarine erosion rate we assessed, we advocate those that employ both water temperature and nearshore wavefield. As high water levels are a prerequisite for erosion, any future changes that increase the frequency with which water levels exceed the base of the bluffs will increase rates of coastal erosion. The certain increases in sea level and potential changes in storminess will both contribute to this effect. As water temperature also influences erosion rates, any further expansion of the sea ice‐free season into the midsummer period of greatest insolation is likely to result in an additional increase in coastal retreat rates.

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“…This positive regime however did not persist, as net annual mass balance was again negative for the 1974/ 75 and 1975/76 balance years ( Table 1). The original 1972 stake network was re-surveyed in 1982 by a research group from the University of Massachusetts (Bradley and Serreze 1987a) as part of a 2year topoclimatic study of the St. Patrick Bay ice caps and surrounding Hazen Plateau (Bradley and Serreze 1987b;Serreze and Bradley 1987). Net mass balance between 1972 and 1982 was -1.3 m w.eq.…”

Section: Previous Studies: Murray and Simmons Ice Capsmentioning

confidence: 99%

Mass balance and area changes of four high arctic plateau ice caps, 1959–2002

Braun

Hardy

Bradley

2004

Geografiska Annaler: Series A, Physical Geography

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Small, stagnating ice caps at high latitudes are particularly sensitive to climatic fluctuations, especially with regard to changes in ablation season temperature. We conducted mass balance measurements and GPS area surveys on four small High Arctic plateau ice caps from 1999-2002. We compared these measurements with topographic maps and aerial photography from 1959, and with previously published data. Net mass balance (b n ) of Murray Ice Cap was -

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Radiation and Cloud Observations on a High Arctic Plateau Ice Cap

Cited by 29 publications

References 19 publications

Meteorological conditions on an Arctic ice cap—8 years of automatic weather station data from Austfonna, Svalbard

Meteorological conditions on an Arctic ice cap—8 years of automatic weather station data from Austfonna, Svalbard

Modeling erosion of ice-rich permafrost bluffs along the Alaskan Beaufort Sea coast

Mass balance and area changes of four high arctic plateau ice caps, 1959–2002

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