Long-term Changes in Precipitation Characteristics at Sturt Meadows, Western Australia

Abstract

Long-term changes in the precipitation data at Sturt Meadows were analyzed by the Mann-Kendall statistics and the Lepage test. Yearly and spring precipitation increased significantly from 1910 to 2008, and the significance levels were p < 0.10 and 0.01, respectively. The data of daily precipitation were classified into two groups (class 1-4 and 5) separated by the distribution of the data, and class 1-4 precipitation increased significantly. There were 4 significant-climatic jumps (1925-27, 1963, 1979-1982 and 1993) by results of the Lepage test. The averages of yearly precipitation during whole years and the latest period are 215.0 and 280.9 mm/year, respectively. The averages of monthly precipitation in February, October and November during the latest period (1993-2008) is higher than those in the previous periods. That in February during the latest period was especially heavy, when the mean precipitation in February was six times higher than that in the previous period. This change was attributed to the increase in the frequency of storm events in February during the latest period. Monthly precipitation exceeding 100 mm/month in February was recorded three times (1995, 2001 and 2006), and this occurred only 2 times in previous periods (1925 and 1975).