Analysis of strong wind events around Adelie Land, East Antarctica

Strong wind events at Dumont d'Urville (DdU), an East Antarctic coastal station, and Dome C, an interior station, were studied to determine if the wind along the Adelie Land coast increases with the approach of the depression from the west of the site or after its passage to the east of it. The events for the year 1993 were studied using synoptic observations, mean sea level pressure charts and composite infrared satellite images. It was found that the winds are enhanced with the approach of a depression from the west towards the DdU coast. The wind increases in response to the decreasing pressure at the coastal site and increasing downslope pressure difference (dp). The wind starts decreasing once the system moves to the east of DdU and the pressure at DdU starts building up, as reported in some earlier studies. The response of wind to the approaching depression is not the same for all the events but depends on the downslope pressure difference and the movement of the depression that is often conditioned by the presence of a blocking high to the northeast. The wind comes down if the system starts penetrating inland due to the presence of the high pressure ridge to the northeast and decreasing dp. It is observed that the winds at Dome C increase to as high as 17 m s-1 with the inland penetration of the depression

Boundary layer convective-like activity at Dome Concordia, Antarctica

The paper presents the micro-meteorological field experiment carried out at the plateau station of Dome Concordia (3300 m a.s.l.) during the Antarctic summer of 1997. The experiment dealt with the study of the trends of boundary layer features and the characteristics of the surface energy and momentum exchanges. A monostatic Doppler sodar, fast-response sensors and radiometers were used for this study. The experiment was part of a program that aims to assess the role of the continental polar regions in shaping the surface circulation over Antarctica. In spite of the markedly stable conditions found throughout the investigated period, some convective-like activity was detected during the warmer hours of the day

Characteristics of the boundary layerat Ny-Ålesund in the Arctic during the ARTIST field experiment

A preliminary analysis of boundary layer data acquired during the Arctic Radiation and Turbulence Interaction Study Experiment (ARTIST) at Ny-Ålesund (Spitzbergen) in 1998 is presented. As expected, the wind fi eld and the thermal structure of the boundary layer are strongly infl uenced by the katabatic fl ow blowing along the Kongsfjorden. In particular, if the large scale circulation has a component along the same direction, the resulting low level wind reaches velocities comparable with geostrophic wind. Stable to neutral conditions occurred most of the time, sustaining inversion or spiky layers respectively, depending on the wind intensity. The behaviour of some micrometeorological parameters was examined in relation to the general fl ow pattern and the characteristics of this area. The highest values of surface sensible heat fl ux (with negative sign) were observed during daytime, in presence of forced convection, due to the transfer of warmer upper layer air into the surface layer

Characterization of the boundary layer at Dome C (East Antarctica) during the OPALE summer campaign

The regional climate model MAR was run for the region of Dome C located on the East Antarctic plateau, during Antarctic summer 2011–2012, in order to refine our understanding of meteorological conditions during the OPALE observation campaign. A very high vertical resolution is set up in the lower troposphere, with a grid spacing of roughly 2 m. Comparisons are made with observed temperatures and winds near the surface and from a 45 m high tower as well as sodar and radiation data. MAR is generally in very good agreement with the observations but sometimes underestimates cloud formation, leading to an underestimation of the simulated downward long-wave radiation. Absorbed short-wave radiation may also be slightly overestimated due to an underestimation of the snow albedo and this influences the surface energy budget and atmospheric turbulence. Nevertheless the model provides sufficiently reliable information that represent key parameters when discussing the representativeness of chemical measurements made nearby the ground surface during field campaigns conducted at the Concordia site located at Dome C (3233 m a.s.l.)