Antarctica is producing atmospheric aerosol of its own from trace gases emitted by the coastal flora and fauna.

[1] Inter-annual variations in Arctic sea ice drift speed (V i ) in were analyzed on the basis of buoy data and atmospheric circulation indices. In the circumpolar and eastern Arctic and the Fram Strait, the annual mean V i was best explained by the sea level pressure (SLP) difference across the Arctic Ocean along meridians 270°E and 90°E, called as the Central Arctic Index (CAI). In general, V i was more strongly related to CAI than to the Dipole Anomaly (DA). This was because CAI is calculated across the Transpolar Drift Stream (TDS), whereas the pressure patterns affecting DA sometimes move far from TDS. CAI also has the benefit of being a simple index, insensitive to the calculation method applied, whereas DA, as the second mode of a principal component analysis, is sensitive both to the time period and area of calculations. In summer, the circulation index most important for the circumpolar mean V i was the SLP gradient across the Fram Strait. In the Canadian Basin in winter, the Arctic Oscillation index was most important. Circulation indices explained 48% of the variance of the annual mean V i in the circumpolar Arctic, 38% in the eastern Arctic, and 25% in the Canadian Basin. The local air-ice momentum flux (t) was always better than the 10 m wind speed in explaining V i , but t outperformed the circulation indices only in the Fram Strait. Atmospheric forcing did not explain the increasing trend in V i in the period

No abstract

The reasons for the relatively strong coastal afternoon surface winds observed along the Gulf of Finland were studied by using a high‐resolution two‐dimensional numerical model in typical summertime conditions. Sea breeze effects were included by defining a clear sky, whereas they were minimized by alternatively defining a thick cloud cover. The geostrophic wind was varied both in speed and direction. A case‐study was made with a three‐dimensional operational forecast model with results that agreed with the two‐dimensional experiments and observations. Strongish afternoon surface winds nearly parallel with the coastline were obtained in the overcast gulf experiments. In these cases, well‐mixed air entering the smooth sea slantwise from over land commenced an inertial oscillation downstream such that the emerging low‐level jet maximum was located just above the opposite coast, causing the strong winds there. If the sky was clear, sea breezes and strong convective mixing further enhanced the coastal surface winds to supergeostrophic speeds. In contrast, weak coastal winds occurred when the sea breeze and the basic flow were nearly opposite. Given the gulf geometry, the sea breeze cell from the opposite coast could be advected over the gulf in a suitable basic flow, which resulted in another minimum in the coastal wind speed as a function of geostrophic wind direction. Copyright © 2005 Royal Meteorological Society.

No abstract