Sentences with phrase «glacier surface»

Isostatic rebound in response to glacier retreat (unloading), increase in local salinity (i.e., δ18Osw), have been attributed to increased volcanic activity at the onset of Bølling — Allerød, are associated with the interval of intense volcanic activity, hinting at a interaction between climate and volcanism - enhanced short - term melting of glaciers, possibly via albedo changes from particle fallout on glacier surfaces.

A comparison of glacier surface elevation in 1983 and 2002 identifies the average thinning in the twenty year period from the USGS aerial photography in 1983 to 2002, for the northern branch is 15 m.

Ablation and associated energy balance of a horizontal glacier surface on Kilimanjaro.

The daytime glacier surface temperature typically has to be greater than the air temperature in order to close the energy budget; in consequence, melting can occur even when the air temperature remains below freezing.

Data from real glaciers are required both to parameterise a model, for which values from similar glaciers in other parts of the world may be used, e.g. glacier surface albedo (Cuffey and Paterson, 2010), and to define variables for the study glacier.

Researchers at the University of Alaska Fairbanks have been taking airborne measurements of glacier surface height using a laser altimeter, an instrument that bounces a laser off of the ice surface and measures how long it takes to return.

The laser altimeter data were extracted for different types of glacier surfaces derived from the Landsat data and compared with the digital elevation model to obtain elevation differences over time.

«Generally, you can expect that regions with large glacier surfaces and very dry warm seasons will see the strongest impacts on river runoff.

Net balance for a given year is then determined by summing the values for each 10m contour for the entire glacier surface.

We conclude by underlining that the observed variation of glacier surface and SLA changes could be explained by the increase of temperature and decrease of precipitation in recent years.

Notably, the quote «Mölg and Hardy (2004) show that mass loss on the summit horizontal glacier surfaces is mainly due to sublimation (i.e. turbulent latent heat flux) and is little affected by air temperature through the turbulent sensible heat flux.»

As he drew closer, he saw water bubbling up from yellow cones — piles of sulfur that accumulated on the glacier surface — and realized it was a sulfur spring.

The research showed that, compared to pure snow and ice, the reflectivity of the glacier (known as the «albedo») can be reduced by up to 80 % in places where coloured microbial populations are extremely dense, leading to the darkening of the glacier surface.

«Our timing was serendipitous, as it meant we were able to see changes in microbial processes over an extremely fast melting season and observe a process from start to end across all habitats on a glacier surface.

Bacteria and other microbes that fell on the glacier surface would have spent a million years being carried downward as more snow fell above them before they eventually plopped into the lakes.

In 1958, a Russian airplane navigator named Robinson was making his landing approach at the newly opened Vostok research station when he noticed a large, flat, oval depression «with gentle shores» on the glacier surface.

For their study, the international team of researchers evaluated satellite - based laser measurements of the glacier surfaces on the Tibetan Plateau between 2003 and 2009.

Associate Professor Alexis Templeton and Dr. Stephen Grasby prospecting for sulfur biominerals in a yellow sulfur deposit forming on a glacier surface in the High Arctic.

It is dissected by several gullies, cut into the unconsolidated sand by streams (melting from the glacier surface is encouraged by the accumulation of dark wind - blown sand, which absorbs solar radiation)[17].

Therefore, if conditions allow the glacier surface to warm to 0 C, the amount of ablation that can be sustained by a given energy input increases dramatically.

Detailed studies of the energy balance and ablation of the Zongo and Chacaltaya glaciers support the importance of air temperature increase, and identify the increase in downward infrared radiation as the main way that the effect of the warmer air is communicated to the glacier surface [Wagnon et al. 1999; Francou et al, 2003].

In particular, through infrared and turbulent heating effects, an increase in air temperature forces the glacier surface to warm, and makes it easier for melting to occur.

The energy balance at the glacier surface shows that the greatest energy available to melt ice comes from the radiative balance.

Annual ice and firn ablation (firn and ice net balance: Mayo et al., 1972) is determined using ablation stakes drilled into the glacier surface and simultaneously checked on the same date in late September.

The longitude and latitude of each glacier is noted in degrees and minutes, the mean slope of the glacier surface, the mean altitude of the glacier, and the surface area of the glacier are also listed.

This prevents a long - lasting snow cover with a high reflectivity to form and protect the glacier surface.

Each program monitors ablation during specific time periods using stakes emplaced in the glacier surface.

But as the snow melts in the spring and summer the black soot concentrations on the glacier surface increase, because the soot particles do not escape in the melt water as efficiently as the water itself.

The glacier surface area had loss of 14.3 5.9 % (0.27 % a1) from 396.2 km2 to 339.5 km2 in 53 years with the loss by 0.12 % a1 in 1958 - 75 to 0.70 % a1 in recent years.

As a consequence, the soot noticeably darkens the glacier surface during the melt season, increases absorption of sunlight, and speeds glacier disintegration.

Data travels from the deep ocean via copper cables to the glacier surface, passes through a weather station, jumps the first satellite overhead, hops from satellite to satellite, falls back to earth hitting an antenna in my garden, and fills an old computer.

The glacier surface receives energy from solar radiation and from downward infrared.

Solar radiation (sunlight) carries energy to the glacier surface.

The energy available for ablation of a glacier is determined by the energy budget of the glacier surface, illustrated in the accompanying figure.

Warming of the glacier surface increases the upward infrared cooling and the upward latent heat flux; it increases the loss by sensible heat flux (or at least reduces the rate at which the glacier surface gains heat).

Even if the temperature of the boundary layer were equal to the temperature of the glacier surface, sublimation could be sustained if (as is typically the case) the relative humidity of the boundary layer were less than 100 %.

If the glacier surface is too cold, it won't get rid of all the heat that it is receiving, and therefore will warm.

If the glacier surface is very cold, it may also receive some energy by latent heat transfer, through frosting of atmospheric moisture onto the glacier.

To achieve balance, then, the glacier surface must warm.

Because of the intense daytime solar radiation (particularly in the tropics), the glacier surface is typically warmer than the air during the daytime.

Because the glacier surface can be warmer than the air, melting can occur even if the air temperature remains below freezing throughout the day.