Reliable data for tropical storm occurrences in the northern
portion of the eastern Tropical Pacific did not become available until
1966. Considering the years 1966-75, sizeable interannual variations
in storm frequency are evident. Six climatological factors are
investigated in an attempt to explain this interannual variation. These
are: (1) the Southeast Pacific atmospheric circulation; (2) sea-surface
temperature anomalies in the eastern Tropical Pacific; (3) the latitudinal
position of the Inter-tropical Convergence Zone in the eastern
Pacific; (4) the vertical zonal wind shear in the region; (5) the number
of tropical systems entering the region from the east; and (6) relationships
with other tropical storm regions of the world. It is not possible,
due to lack of data coverage to adequately examine item (4) at this
time. The five remaining factors, however, demonstrate that the
annual tropical storm frequency in the eastern Tropical Pacific is
apparently affected by cross-equatorial and cross-Pacific influences.
The strength of the South Pacific Subtropical High appears to be
particularly important. In addition, items (1), (2) and (3) provide the
type of data that could be used in statistical models to predict the
number of tropical storms that will occur in a given year. (Data used
must be available before the onset of the storm season.) Two ordinary
multiple regression models involving factors (1), (2), and (3) are
proposed for this purpose. Both models are found to be statistically
significant (at the .05 level), but due to the very limited amount of
data, are of questionable value at present. When a sufficient number
of years of data become available, it is expected that models of this
type can be used quite effectively for predicting annual tropical storm
frequency over this region. / Graduation date: 1977
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/28335 |
| Date | 30 July 1976 |
| Creators | Short, Kent S. |
| Contributors | Quinn, William H. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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