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resolution over the conterminous United States was created by using a regional,
seasonal Advection-Aridity model, which provided a tool for studies on climate
change and variability based on comparison of intra-annual trend results with
results from another study.
6.2.4 Climatic Change
Burn (1994) examined the impact of climatic change on the timing of spring
runoff by using a nonparametric statistical trend test applied to the datasets of
84 natural rivers from the west-central region of Canada. The results indicated
that a greater number of rivers exhibit earlier spring runoff than can be attributed
to the chance occurrence. The impacts on the timing of spring runoff were
found more prevalent in the recent portion of the records, which is consistent
with what one would expect if the impacts are due to the greenhouse gas-
induced climatic change.
Charvátová (1995) processed the time series of solar and volcanic activities
as well as the time series of surface air temperature in connection with climatic
change in recent centuries in central Europe. The subintervals used
corresponded to the two types of solar motion, the ordered and chaotic. The
exceptional and repeating behaviour of these phenomena in the intervals of
the ordered motion of the Sun, in spacing of 180 years, and a quite different
behaviour in the intervals of chaotic motion were demonstrated by means of
statistical characteristics. The results enabled predictions because the solar
motion can be computed well in advance.
Vassilev and Georgiev (1996) reported that climatic changes have already
started in Bulgaria. Because water resources to a great extent depend upon
climate dynamics, the linkage of climatic fluctuations and water resources
were developed using the time-series analysis of climatic parameters and
some river runoff characteristics and their correlation. The results of this
study pointed to several problems of regional and local importance. It was
concluded that the climatic change manifested during last 15 years has
significantly influenced the river runoffs. A study of the recent prolonged
drought and the influence of changes on water resources and human activity
begins with characterizing climate-hydrology linkages.
Westmacott and Burn (1997) evaluated the possible effects of climate
change on four hydrologic variables pertaining to the magnitude and timing of
hydrologic events in the Churchill-Nelson River basin of west-central Canada.
By using the Mann-Kendall trend test, and a regionalization procedure, the
severity of climatic effects within the river basin was quantified, which was
then used to create awareness about future consequences of water resource
planning and management strategies. It was found that the magnitude of
hydrologic events decreased during the study period, while the snowmelt
runoff events occurred earlier. The only exceptions to this behaviour were the
spring mean monthly streamflows, which exhibited increasing trends due to
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