6 CLIMATOLOGY
Alaska experiences four distinct climatic zones
and its mountains produces a more Transition-type cli-
(AEIDC 1974)--Arctic, Continental, Transition, and
mate, especially in the upper reaches of the Inlet. In
Maritime (Fig. 21). While the weather conditions in
addition, weather patterns and climate within the Cook
each zone can vary dramatically from normal, the
Basin are affected by the warm Alaska Current; the
zones can be characterized by general patterns. Me-
shallow bathymetry of the Inlet; its high tidal varia-
teorological conditions in the Arctic zone (extending
tion and fast currents; and the Inlet's high north-to-
from the Brooks Range northward to the Arctic Ocean)
south salinity gradient. These conditions prevent an
are primarily influenced by the inflow of cold, polar
intact ice cover from forming over the Inlet during
air masses. Winds along the northern coast are strong
winter. The broken ice cover and newly forming ice
but diminish with distance inland.
release heat from the water to the atmosphere, thus
Most of interior Alaska is Continental in climate.
moderating the climate.
This region is distant from ocean waters, so the cli-
mate is drier and air temperatures fluctuate consider-
6.1 Source and description of climatological data
ably more, both seasonally and diurnally. Summer tem-
for Cook Inlet
The meteorological information presented in this
peratures are generally quite high, while winter
report was extracted, summarized, and supplied to us
temperatures can be extremely low. Precipitation and
by the Air Force Combat Climatology Center
winds are relatively light.
(AFCCC) in Asheville, North Carolina. The stations
The weather in the Maritime zone is dominated by
selected for this study are the "first-order" NWS sta-
the presence of nearby ocean waters. Air temperatures
tions in the vicinity of Cook Inlet. First-order sites rou-
are moderated year-round by the proximity of oce-
tinely record station parameters on an hourly basis
anic water. Because of the enormous heat capacity of
throughout the year. Three of these stations--Anchor-
the nearby ocean waters, summer air temperatures are
age, Kenai, and Homer--lie along Cook Inlet's east-
lower and winter temperatures are significantly higher
ern coastline, and the fourth--Kodiak--is located on
than in areas that are more inland. In addition, the ocean
an island in the Gulf of Alaska. Unfortunately, there
acts as a large source of moisture, resulting in much
are no first-order stations along the Inlet's western
more precipitation along the coast as rain in summer
coast from which to obtain comparable long-term me-
and snow in winter, especially in windward, higher-
teorological records. The stations are listed and de-
elevation areas. A maritime climate is also character-
scribed in Table 8.
ized as having persistently strong surface winds.
Summary data for the four stations were compiled
The Transition zone is generally the narrow region
by AFCCC for January 1973 to December 1997.
between the Continental and Maritime zones, where
Monthly means, extremes, and occurrence frequen-
the climatic conditions are something between the two
cies for air temperature, wind speed, wind direction,
sets of conditions that exist in the adjacent zones. Cook
and sea level pressure are shown in Appendices D, E,
Inlet predominantly experiences a Maritime climate;
and G.
however, the blocking effect of the Kenai Peninsula
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