Investigation of streamflow variation using an innovative trend analysis approach in Northwest Iran

Tuesday 30 june 2015

12:51 - 12:54h at North America (level 0)

Themes: (T) Extreme events, natural variability and climate change, (ST) Hydrological extremes: floods and droughts, Poster pitches

Parallel session: Poster pitches: 5I. Extreme - Flood Drought

Climate change and its impact on hydrological regime has drawn growing attention in recent years. Using mean monthly runoff at 3 gauge stations from 1954 to 2008 as well as precipitation and temperature series at 2 meteorological stations from 1951 to 2008 in the downstream of Jinsha River and the Three Gorges section, this paper investigates the inner-annual and inter-annual variation, tendency, mutability and periodicity of hydrological and meteorological factors with moving average method, Mann-Kendall rank correlation test, sequential clustering analysis, mean value test method and wavelet analysis. In addition, the sensitivity of runoff to precipitation and temperature change is analyzed. The results show that: (1) Distribution of runoff in the study area is highly uneven within a year, while the inter-annual variation is not as significant as inner-annual variation. (2) The annual runoff in the Three Gorges section presents a downtrend and abrupt changes in 1968 and 2005, while precipitation shows an increasing trend with obviously mutation points in 1961 and 1995. Similarly, runoff in the downstream of Jinsha River indicates an uptrend and an abrupt change in 1997, meanwhile, precipitation reflects the opposite trend with a mutation point in 1991. Furthermore, temperature in the study area demonstrates an obvious uptrend. (3) Series of runoff, precipitation and temperature all show main cycles less than ten years and secondary cycles over 20 years. (4)Besides, Pearson correlation coefficients implies that runoff is not only in a positive correlation with precipitation, but also in a negative correlation with temperature in Three Gorges section. However, these correlations in the downstream of Jinsha River does not reach significant level, which indicates that human activities can undermine the sensitivity of runoff to climate change in the downstream of Jinsha River

More information