Fluxes and energy budget at Dome-C, Antarctica, between 1996 and 2003

The Antarctic Planetary Boundary Layer (PBL) plays a crucial role in connecting the atmospheric, the oceanic, and cryospheric components of the Antarctic climatic system. The knowledge of the Antarctic PBL is still poor in terms of theoretical understanding as well as in terms of available data. The annual radiative balance is negative and therefore the air layer close to the surface is cooled for most of the year. In spite of low surface temperature, a regular day time boundary layer evolution was observed, as well as a convective activity. It became crucial to understand these processes and study processes connected to the formation of the inversion wind, to investigate the relationship between the surface energy balance and katabatic wind occurrence, to assess the capability to detect the vertical motions associated with the secondary meridional circulation, on the base of the interaction between the large scale and the low level circulation, and with position of the polar vortex. Several campaigns have been carried out on the Antarctic plateau in the station of Dome-C to achieve to answer to the cited problems as well as to test the instrumentation to be deployed in a future long term mission. Depending on the mission objective, several instruments could be included. Based on the previous Antarctic experience of Sodar, but limited by the logistics two vertical antenna Doppler minisodar (MS), to study the mixing layer height (MH) and the associated vertical wind (W) field evolution was first deployed. A three meter micromet mast (MM) with a sonic anemometer (SA) and a fast hygrometer (FH) KH20 to estimate the turbulent fluxes (TF), a net radiation station (NR) to calculate the radiation budget (RB), a ground temperature sensors station (GT) and a flux plate (FP) to determine the energy balance (EB) at the interface between the atmosphere and the snow covered soil were installed. Micrometeorological tower (MT) equipped with sensors to measure the wind speed and direction (WD) , air temperature (TA), humidity (RH), radiation budged, soil temperature and heat fluxes were mounted. Also a microlidar (ML) for the aerosols and ice particles (IP) profiling, and a passive microwave radiometer (MTP-5) for the PBL temperature profiling (TP) were used. Below, the periods, the instruments deployed and parameter measured at the Italian-French base of Dome Concordia are listed: DATE: 20/01/97-30/01/97: PLATFORM: MS, MM; INSTRUMENT: 2 ant.MS, SA, FH, NR, GT, FP; PARAMETER (range/ height): MH (400m), WD, W, TF, RB, EB (3m). DATE: 08/12/99-03/02/00: PLATFORM: MS, MM; INSTRUMENT: 2 ant. MS, SA, NR, GT, FP; PARAMETER: MH( 400m), WD, W, TF, RB, EB (3m). DATE: 18/11/02-17/1202: PLATFORM: MTP-5,ML; INSTRUMENT: MTP-5,ML; PARAMETER: TP (600 m), IP (500 m)