Abstract: We use the distribution of Ertel's potential vorticity (PV) on the 850 K isentropic surface to establish a climatology for the transient evolution of the planetary scale circulation in the Northern Hemisphere winter ...

Abstract: The stratospheric major warming of early December 1987 is analyzed using NMC observations of temperature and geopotential. This warming is distinguished as the earliest major warming ever recorded in the Northern Hemisphere ...

Abstract: Twenty years of rawinsonde data (1973?1992) were examined in conjunction with European Centre for Medium-Range Weather Forecasts (ECMWF) analyses and outgoing longwave radiation (OLR) in 1980?1989 to determine the horizontal ...

Abstract: Using 30 years of Northern Hemisphere geopotential data, from 1000 to 10 hPa, the link between three fundamental modes of tropospheric variability [the Pacific/North America (PNA), Western Pacific Oscillation (WPO), and ...

Abstract: Using 25 years of National Meteorological Center (NMC) data for 1964?88 the relation between tropical and extratropical quasi-biennial oscillations (QBOs) was examined for zonally averaged quantities and planetary-wave ...

Abstract: Eliassen-Palm (EP) diagrams have been shown to be very useful diagnostics in both the troposphere and the stratosphere. However, the idea that the EP flux divergence is the sole forcing of the mean wind by the eddies can ...

Abstract: Often there is a need to consider spatial weighting in methods for finding spatial patterns in climate data. The focus of this paper is on techniques that maximize variance, such as empirical orthogonal functions (EOFs). ...

Abstract: The dynamical coupling between the stratospheric and tropospheric circulations yields a statistically significant level of potential predictability for extreme cold events throughout much of the Northern Hemisphere (NH) ...

Abstract: This study examines the temporal evolution of the tropospheric circulation following large-amplitude variations in the strength of the Southern Hemisphere (SH) stratospheric polar vortex in data from 1979 to 2001 and ...

Abstract: strong link exists between stratospheric variability and anomalous weather patterns at the earth?s surface. Specifically, during extreme variability of the Arctic polar vortex termed a ?weak vortex event,? anomalies can ...