A Statistical Study of Temporal Trends in Rainfall Over New South Wales

摘要

The main objective of this study is to carry out trend analysis by using Mann Kendall’s tau test in monthly rainfall data of New South Wales over a 99 year period (1912-2010). Trend analysis was performed using non parametric Kendall’s tau test to monthly time series of rainfall. This study reveals that the increasing trend dominates the decreasing trend. A total of 492 stations are tested out of which 490 (99.59) shows a (positive or negative), out of which 202 (41.05) has negative trend, whereas 288 (58.53) stations has uptrend. Number of stations with significant increasing or decreasing trends equals to 49 (9.95), stations with significant increasing trends in data sets dominates over significant decreasing trends over New South Wales. Out of 49 stations, 28 stations have significant increasing trends whereas 21 stations have significant decreasing trends. Two stations were found to have no trend for the month of May and October. Highest number of decreasing trends are found to be in the months of March and April (28 each) while least number of decreasing trends were observed in the month of November (01). Highest number of increasing trends were observed in November (40) out of which 08 are significantly increasing while least number of increasing trends was in April (7) out of which none was significantly increased. Significant increasing trends in cool season were equal to summer season. The highest number of significant decreasing trends was observed in April and June (06 each). This study does not aim to explore the relationship of Climatic indices with rainfall.