The northwestern and northeastern Pacific Oceans are known to contain the world's largest number of named tropical cyclones (TCs)
during their respective storm seasons. In this study, some characteristics of the TCs in these two cyclone basins are examined using outgoing longwave radiation (OLR) and ECMWF Re-Analyses (ERA) data sets for the 15-year period, 1979-93. Statistics and results are compiled for a five (six) month period, June-October (June-November), which represents the eastern (western) Pacific primary TC season. It is well known that the tracks followed by the TCs in the eastern Pacific are more concentrated than their counterpart in the western Pacific. We find, for example, that 50% of all TCs in the eastern Pacific pass through a 5°×5° lat/lon box, centered at 15°N, 105°W. This box also
contains the highest frequency of TCs in the eastern Pacific. Moreover, in our study, 72% of the TCs passing through this box were intensifying.
Our recent studies, as well as those of others, showed that spectral peaks in OLR occurred between one and three weeks in the central portion of both TC basins. Our present results show that the axes of maximum frequency of TCs and maximum variance of 6-25 day bandpass-filtered (bpf) OLR are nearly coincident across the entire western Pacific TC basin. In the eastern Pacific, these two axes are also
coincident, but only between 90°W and 110°W. We find that peak values of both TC frequency and bpf OLR variance occur at 15°N, 105°W for
the eastern Pacific and at 15°N, 130°E for the western Pacific.
In our presentation, we will show some time series of selected variables that have been averaged over 5°×5° lat/lon boxes centered
on the two grid points mentioned above. We will also show some results that have been composited as a function of different TC strengths. Among the variables shown will be OLR, relative vorticity at 850 hPa, divergence at 150 hPa, vertical motion at 400 hPa, and precipitable water. If time permits, we will show some interannual variability results.