Effects of Drifting Snow on Surface Radiation Budget in the Katabatic Wind Zone, Antarctica (original) (raw)

1985, Annals of Glaciology

Effects of drifting snow are examined from measurements of radiation fluxes at Mizuho Station in the katabatic wind zone, Antarctica. A good correlation is found between the difference of downward longwave fluxes measured at two heights and wind speed used as an index of drifting snow. The wind increases the downward flux at a rate of 2 W m-2/m s-2when wind speed is higher than 13 m/s. Drifting snow suppresses the net longwave cooling at the surface. Direct solar radiation is depleted greatly by the drifting snow; however, the global flux decreases only slightly, compensated by the large increase of the diffuse flux, at a rate of about 1% for each 1 m/s increase in wind speed. At Mizuho Station, the effect on longwave radiation prevails throughout the year. The relation between snow drift content and wind speed is obtained from shortwave optical depth measurements as a function of wind speed. A simple parameterization of radiative properties is given.

The Effect of Blowing Snow on Katabatic Winds in Antarctica

Annals of Glaciology, 1985

An acceleration of the katabatic winds during periods of blowing snow was observed in Adelie Land, Antarctica. Data collected by Automatic Weather Stations' (AWS) showed a change in the relationship between the katabatic term of the surface geostrophic wind (katabatic force) and the wind speed for periods of blowing snow. When measurements of the katabatic force were plotted against the cube of the wind speed, the slope was steeper for wind speeds at less than a threshold speed for blowing snow. The difference between these two slopes was partly explained by the effect of blowing snow entrained into the atmospheric boundary layer.

Snow Albedo Seasonal Decay and Its Relation With Shortwave Radiation, Surface Temperature and Topography Over an Antarctic ICE Cap

2021

We have characterized the snow albedo decay over Hurd Peninsula, Livingston Island, Antarctica, for the period 2000–2016. The snow albedo was obtained from the MOD10A1 product of the spaceborne MODIS sensor. A low-pass filter is applied to the data in order to eliminate short-term variations and retain the seasonal variation of albedo. The seasonal albedo was fitted to an exponential decay function to obtain the decay rate, the duration and the starting date of the decay. On average, albedo decay starts in late September and lasts for 96 ± 20 days. Snow melting lags behind snow albedo decay. This lag is due, on the one hand, to the occurrence of dry-snow metamorphism and sublimation in the early stages of the decay, and on the other hand to persisting subsurface melting after the completion of the metamorphic processes at the surface. The albedo decay is mainly driven by the shortwave incident radiation, with air and near-surface temperatures unexpectedly playing a minor role. Near-...

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