The gravity wave field in the lower stratosphere (between 15 km and 22 km altitude) above Mount Pleasant Airport (51°49’S, 58°26’W), on the Falkland Islands is studied using over 2100 high-resolution radiosonde soundings from 2002-2010. The seasonal variation in vertical direction of propagation shows a small decrease in numbers of upward propagating waves that is related to critical level filtering, however there is a very large increase in numbers of downward propagating waves between July and September; this is attributed to the proximity of the edge of the polar vortex. There is a seasonal variation in gravity wave energy density, with a large peak during the austral autumn equinox; this is markedly different to results in the literature both from Rothera, on the Antarctic Peninsula, and stations on the main Antarctic continent. This seasonal pattern has been shown to be linked to variations in the sources of upward propagating gravity waves. The seasonal variation in gravity wave characteristics above Mount Pleasant Airport seen in our results suggest that the gravity wave field in this region is determined by a combination of different gravity wave sources located above and below the lower stratosphere.
Among other roads, construction work for the drainage project continues on Sixth Street looking toward Bay Avenue. Work to be completed in the week of Dec. 17-21:Construction contractor Feriozzi Concrete will continue work on Pleasure Avenue between Sixth Street and Seventh Street, as well as Sixth Street from Bay Avenue to the bulkhead. Pipe crews will install inlets on Pleasure Avenue before finishing tie-ins at both Third Street and Bay Avenue and at Sixth Street and Bay Avenue. A second crew will begin installation of the pump station at Sixth and Bay. Road contractor South State will begin work early next week. The contractor will be topping Third Street, milling and paving Seventh Street from West to Bay, as well as Moore and Haven avenues between Seventh and Eighth.Another contractor, Arthur Henry, will continue the installation of the bulkhead at Third Street. Project Design:See Design Presentation for DetailPaving is scheduled for the intersection of Seventh Street and Moore Avenue.