Seasonal and diurnal cycles can be found in averages and climatic trends of climatic records.  A few years ago I began to work on a new statistical technique that can be applied to records with such cycles.  The approach and details of the technique have been described in several recent publications (see below).  This technique produces unprecedented opportunities to analyze and visualize climatic change.  There is no restriction that the climatic process be stationary, and records can contain seasonal and diurnal cycles in the moments of the statistical distribution (means, variances, and higher moments) of the observed variables and their trends.  The technique can be applied to historical observations of meteorological stations with many changes in their times of observation, and can also be applied to climate model output.  It will be described and illustrated with several examples, including:

1. Analysis of trends of  50-year records of surface air temperature at a several US stations, showing that decreases in diurnal temperature range occur only in summer and fall.

2. Analysis of trends in satellite-observed sea ice, showing that the Northern Hemisphere trend is much different from that in the Southern Hemisphere.

3. Analysis of the trend in satellite-observed tropospheric temperature, showing that the upward trend of tropospheric temperature for the past 25 years is the same as the trend in surface temperatures.  Previous analyses showing different trends, and claims that that result invalidated global warming from surface temperatures and predictions of global warming from climate models, are no longer justified.

Vinnikov, Konstantin Y., Alan Robock, Donald J. Cavalieri, and Claire L. Parkinson, 2002: Analysis of seasonal cycles in climatic trends with application to satellite observations of sea ice extent. Geophys. Res. Lett., 29 (9), 10.1029/2001GL014481. PDF file

Vinnikov, Konstantin Y., Alan Robock, and Alan Basist, 2002: Diurnal and seasonal cycles of trends of surface air temperature. J. Geophys. Res., 107 (D22), 4641, doi:10.1029/2001JD002007. PDF file

Cavalieri, D. J., C. L. Parkinson, K. Y. Vinnikov, 2003: 30-Year satellite record reveals contrasting Arctic and Antarctic decadal sea ice variability, Geophys. Res. Lett., 30 (18), 1970, doi:10.1029/2003GL018031.  PDF file

Vinnikov, K. Y., and N. C. Grody, 2003: Global warming trend of mean tropospheric temperature observed by satellites, Science, 302, 269-272. PDF file

Vinnikov, Konstantin Y., Alan Robock, Norman C. Grody, and Alan Basist, 2004: Analysis of diurnal and seasonal cycles and trends in climatic records with arbitrary observation times.  Geophys. Res. Lett., in press.  PDF file