For 20 years the biennial symposia organized by the International Society for Acoustic Remote Sensing of the Atmosphere and Oceans and Associated Techniques (ISARS) have been held in different countries The original papers collected in the proceedings of the symposia reflect the development of ideas, equipment, and methods, plus results obtained in the area The spectrum of themes discussed at the symposia is broad More than 60% of the papers were devoted to the role of sodars in atmospheric boundary-layer research This paper presents an overview of the development of sodar technique as elucidated in the proceedings of 11 ISARS symposia Topics include (1) instrumentation, (2) methods of measuring different meteorological quantities and their turbulence characteristics, and (3) validating the methods by comparison of sodar data with in situ measurements

Two decades of progress in SODAR techniques: a review of 11 ISARS proceedings

Comparison between the results of a Monte Carlo atmospheric diffusion model and tracer experiments

Implementation of a multiaxial Doppler sodar system with advanced data processing

Dumont d'Urville, on the Antarctic coast, is an area well known for the presence of strong katabatic winds blowing from the Antarctic plateau toward the sea almost all year. Since January 1993, a three-axis Doppler sodar has been operating in this area to investigate the variability of the boundary layer structure and dynamics. In this paper, the capabilities, behavior and advantages of using this ground-based remote-sensing system in Antarctica are evaluated after one year of measurements. This instrument may play an important role in boundary layer studies in remote regions where other profiling techniques (e.g., kitoons, slow ascent balloons) are difficult and expensive. All year long, except in summer when the signal-to-noise ratio was dramatically reduced by the noise of a large group of Adelie penguins, reliable measurements were available up to 900 m. The reliability of the vertical wind velocity has been checked and the influence of the local topography on the flow pattern has been evaluated. Some preliminary results regarding the statistical analysis of the horizontal and vertical velocities and an overview of the main physical processes are also shown. The statistical analysis of the wind speed shows that the wind blows from the 30 ° angular sectors centered at 90 °, 150 °, 180 °, and 0 °. The winds from 90 ° and 150 ° constitute the main local circulation and have, most of the time, the characteristics of a katabatic flow, whereas the winds blowing from 180 °, arising from the surface temperature difference between the sea and the land, are land breezes. Strong winds coming from the ocean (0 °), attributable to the inland penetration of depressions, have been observed in May, October, and November. Finally, some examples of the observed thermal structures, as depicted in the facsimile recording, are shown.

A. Marzorati

Papers

Simultaneous operation of a sodar system in monostatic and bistatic modes: Preliminary results