snow-cover

The calculations require several assumptions about soil, organic layer, vegetation, and snow-cover properties [55].

Permafrost in the Arctic 2009

Variability and trends in the annual snow-cover cycle in Northern Hemisphere land areas, 1972 – 2000.

Phenotypic responses of arctic species to changes in climate and ultraviolet-B radiation 2009

Datasets of satellite observations of sea-ice and snow-cover extent [12], snow water equivalent from the Special Sensor Microwave Imager [13], cloudiness [14], and the radiation budget [15] are available from the National Aeronautics and Space Administration (Goddard Institute for Space Studies, Langley Atmospheric Sciences Data Center) and the National Oceanic and Atmospheric Administration (National Climatic Data Center, National Snow and Ice Data Center – NSIDC).

Arctic climate variability in the twentieth century 2009

The decrease in snow-cover duration is projected to be greater in southern and western Siberia than in northern and eastern Siberia, and greater in the spring season (section 6.4) when insolation is relatively high.

Permafrost in the Arctic 2009

Observations show that precipitation has increased by up to 20% in northern latitudes within the last 40 years (section 2.6.2.2), although there has been a 10% decrease in snow-cover extent in the Northern Hemisphere in the last 20 years (section 2.4.1).

Phenotypic responses of arctic species to changes in climate and ultraviolet-B radiation 2009

Field measurements conducted at Alert, Canada, suggest that a 10 cm snow-cover depth reduces the amount of transmitted 321 nm UV radiation by two orders of magnitude [45].

Factors affecting surface ultraviolet radiation levels in the Arctic 2009

It is very probable that snow-cover extent around the periphery of the Arctic, sea-ice extent averaged over the Arctic (during at least the past 40 years), and multi-year sea-ice extent in the central Arctic have all decreased.

Summary and key findings of ACIA on Arctic Climate - Past and Present 2009

In addition, even accurate point measurements may not be representative of large-area or regional snow-cover conditions.

Snow cover in the Arctic 2009

For example, a reduction in snow-cover extent and a shrinking of the marine cryosphere would increase heating of the surface, which is very likely to accelerate warming of the Arctic and reduce the equator-to-pole temperature gradient.

Summary and key findings of ACIA on Arctic Climate - Past and Present 2009

Surface air temperature and snow-cover projections from the five ACIA-designated climate models and the older HadCM2 model [61], forced with the B2 emissions scenario (section 4.4.1), were used as input to the soil model to project the active-layer and mean annual ground-temperature dynamics in northern Alaska between 2000 and 2100.

Permafrost in the Arctic 2009