Valley floor climate observations from the McMurdo dry valleys, Antarctica, 1986–2000

Abstract

[1] Climate observations from the McMurdo dry valleys, East Antarctica are presented from a network of seven valley floor automatic meteorological stations during the period 1986 to 2000. Mean annual temperatures ranged from À14.8°C to À30.0°C, depending on the site and period of measurement. Mean annual relative humidity is generally highest near the coast. Mean annual wind speed increases with proximity to the polar plateau. Siteto-site variation in mean annual solar flux and PAR is due to exposure of each station and changes over time are likely related to changes in cloudiness. During the nonsummer months, strong katabatic winds are frequent at some sites and infrequent at others, creating large variation in mean annual temperature owing to the warming effect of the winds. Katabatic wind exposure appears to be controlled to a large degree by the presence of colder air in the region that collects at low points and keeps the warm less dense katabatic flow from the ground. The strong influence of katabatic winds makes prediction of relative mean annual temperature based on geographical position (elevation and distance from the coast) alone, not possible. During the summer months, onshore winds dominate and warm as they progress through the valleys creating a strong linear relationship (r 2 = 0.992) of increasing potential temperature with distance from the coast (0.09°C km À1 ). In contrast to mean annual temperature, summer temperature lends itself quite well to model predictions, and is used to construct a statistical model for predicting summer dry valley temperatures at unmonitored sites.

Sediment Melt-Migration Dynamics in Perennial Antarctic Lake Ice

“…The lake is situated 16 m above sea level, with a length, width, and maximum depth of 5.2 km, 1.2 km, and 20 m, respectively (Wagner et al, 2006). The mean annual air temperature at Lake Fryxell is approximately 220 uC, which is 2-3 uC colder than at neighboring Lakes Hoare and Bonney further west (Doran et al, 2002b). The summer air temperatures at Lake Fryxell are subfreezing, with mean values ranging from 25 to 28 uC (Doran et al, 2002b;Fountain et al, 1999).…”

Sources of edaphic cyanobacterial diversity in the Dry Valleys of Eastern Antarctica

“…They are characterized by extremely low temperatures and precipitation, the latter occurring only as snow, which is largely lost by sublimation (Doran et al, 2002). These valleys are considered to be the coldest, most arid deserts on Earth (Cowan et al, 2002;Doran et al, 2002). In general, most of the mineral soils of the valley floors lack any visible cyanobacterial or algal growth, whereas biomass is more apparent in glacial streams and lake margins (Taton et al, 2006a).…”

“…They are characterized by extremely low temperatures and precipitation, the latter occurring only as snow, which is largely lost by sublimation (Doran et al, 2002). These valleys are considered to be the coldest, most arid deserts on Earth (Cowan et al, 2002;Doran et al, 2002).…”

Mid-Miocene cooling and the extinction of tundra in continental Antarctica

“…Together, the fossil data suggest that MST was Ϸ5°C. In comparison, the MST at the site today is approximately Ϫ12°C (22).…”