– The purpose of this paper is to focus on the climatic trends of mean annual temperature and annual precipitation from 1931 to 2000, in four regions of the USA: Northeast, South Atlantic, North Central, and Pacific West.
– Five-year moving averages are calculated for each climatic variable of all regions and used for the trend analysis. Regression analysis was performed to evaluate the level of significance for each trend line. A trend with p<0.0001 is considered statistically significant throughout the study.
– The data show a 0.62°C increase in temperature in the Pacific West from 1931 to 2000. Over the same time period, precipitation has increased by 10.4 centimeters in the North Central Region, which is 10 percent higher than the long-term average for the region.
– The 0.62°C increase suggests that the Pacific West may be experiencing the effect of global warming because this finding is consistent with the result of the Canadian climatic trend study by Zhang et al. who also found that annual precipitation has increased by 35 percent in southern Canada over the same period, which coincides with the increasing trend of precipitation found in the North Central Region. With the best available data and the findings from other studies, the authors are confident that the warming trend in the western USA is likely linked to the increasing sea surface temperature of the Pacific Ocean.
