The spatial patterns of precipitation changes from 1901 to 2005 for the study region are easily observed in summer and fall, but are less distinct in winter, spring, and in the annual total.
(map) Spring precipitation values do not show a clear pattern of change. Areas of increasing and decreasing precipitation trends appear adjacent to each other without any discernable pattern. The magnitudes of the changes are less than those of summer and fall.
(map) There has been a widespread decrease in precipitation during the summer. Some stations showed an increase in precipitation. With the exception of Sumter, SC, those stations only show a slight increase in precipitation. The decreases in precipitation often exceeded four inches throughout the study region.
(map) Contrary to the summer pattern of decreased precipitation, the fall precipitation trend pattern shows strong increases for almost the entire study region. Increases in precipitation tend to be greater than two to three inches. Only three stations along the lower South Carolina and Georgia border showed a slight decrease.
(map) Winter precipitation values do not show a clear pattern of change. Most of the changes are small and intermixed, with the possible exceptions of the interior regions and eastern North Carolina. These regions have some decreases similar in magnitude to summer trends. The decrease in precipitation in the interior regions is supported by other research conducted by the South Carolina State Office of Climatology; research that shows a clear decrease in winter precipitation in the interior from 1931 to 2000.
(map) The map of annual changes in precipitation is similar to the spring pattern. Stations that experienced increases are adjacent to areas that experienced decreases without any distinct trend pattern. The unclear annual changes suggest uncertainty inherent with climate models regarding uniform spatial precipitation trends associated with model climate change.
