Comparative Analysis of Rainfall Trends in the Jinghe River Basin During
Trend analysis is widely applied in hydrometeorological research.
Considering that Innovative Trend Analysis (ITA) and Innovative
Polygonal Trend Analysis (IPTA) can detect small variations on annual
and smaller scale, rainfall trends at 14 hydrometeorological stations in
the Jinghe River Basin were analyzed by ITA, IPTA and Mann Kendall test
(MK). The results showed that the rainfall trends are subsistent from
1959 to 2014. Comparing the results of ITA and MK on annual level, it
was determined that trends are consistent, but only two stations passed
the 90% significance test through MK, while all stations passed the
significance test through ITA. Accordingly, the ITA method proved to be
better than MK in detecting small changes in time series. Changes in
high and low values, obtained by the ITA method, reflected flood and
drought trends in the basin. In addition, IPTA is an improved ITA method
that is suitable for a relatively short time span. Through the IPTA
method for analyzing the monthly precipitation trends, the results
showed that rainfall at 14 stations increased in January, February,
March, June and December, and decreased significantly in September.
Therefore, the methodology applied in this study can provide detailed
recommendations for hydrometeorological research.