Abstract
A substantial decline in North American cyclone and anticyclone activity has been documented by several recent studies based on counts of disturbance tracks. An independent method of assessing long-term trends in synoptic-scale activity based on sequential spectral analysis of station pressure is suggested. The efficacy of this approach is supported by previous studies relating the spatial distribution of variance of band-pass filtered pressures to preferred cyclone tracks. However, examples of a preliminary application of the spectral method to three widely separated stations using approximately 30 years of winter data fail to reveal any significant long-term trends in the variance of pressure for synoptic-scale time periods.
