| 1. |
- Ye, Xuchun, et al.
(författare)
-
Distinguishing the relative impacts of climate change and human activities on variation of streamflow in the Poyang Lake catchment, China
- 2013
-
Ingår i: Journal of Hydrology. - : Elsevier BV. - 0022-1694 .- 1879-2707. ; 494, s. 83-95
-
Tidskriftsartikel (refereegranskat)abstract
- Under the background of global climate change and local anthropogenic stresses, many regions of the world have suffered from frequent droughts and floods in recent decades. Assessing the relative effect of climate change and human activities is essential not only for understanding the mechanism of hydrological response in the catchment, but also for local water resources management as well as floods and droughts protection. The Poyang Lake catchment in the middle reaches of the Yangtze River has experienced significant changes in hydro-climatic variables and human activities during the past decades and therefore provides an excellent site for studying the hydrological impact of climate change and human activities. In this study, the characteristics of hydro-climatic changes of the Poyang Lake catchment were analyzed based on the observed data for the period 1960-2007. The relative effect of climate change and human activities was first empirically distinguished by a coupled water and energy budgets analysis, and then the result was further confirmed by a quantitative assessment. A major finding of this study is that the relative effects of climate change and human activities varied among sub-catchments as well as the whole catchment under different decades. For the whole Poyang Lake catchment, the variations of mean annual streamflow in 1970-2007 were primarily affected by climate change with reference to 1960s, while human activities played a complementary role. However, due to the intensified water utilization, the decrease of streamflow in the Fuhe River sub-catchment in 2000s was primarily affected by human activities, rather than climate change. For the catchment average water balance, quantitative assessment revealed that climate change resulted in an increased annual runoff of 75.3-261.7 mm in 1970s-2000s for the Poyang Lake catchment, accounting for 105.0-212.1% of runoff changes relative to 1960s. However, human activities should be responsible for the decreased annual runoff of 5.4-56.3 mm in the other decades, accounting for -5.0% to -112.1% of runoff changes. It is noted that the effects of human activities including soil conservation, water conservancy projects and changes in land cover might accumulate or counteract each other simultaneously, and attempts were not made in this paper to further distinguish them.
|
|
| 2. |
- Ye, Xuchun, et al.
(författare)
-
Similarity, difference and correlation of meteorological and hydrological drought indices in a humid climate region - the Poyang Lake catchment in China
- 2016
-
Ingår i: HYDROLOGY RESEARCH. - : IWA Publishing. - 1998-9563 .- 0029-1277 .- 2224-7955. ; 47:6, s. 1211-1223
-
Tidskriftsartikel (refereegranskat)abstract
- Based on the estimation of standardized precipitation-evapotranspiration index (SPEI) and standardized runoff index (SRI), this study investigated the variability and correlation of hydrological drought and meteorological drought in a humid climate region - the Poyang Lake catchment in China. Results indicate that the occurrences of hydrological droughts in the catchment are different from those of meteorological drought on both a seasonal and annual basis. However, annual variability of both indices showed the same periodic variation characteristics during the study period. With comparison of the performance of SPEI and SRI time series at different timescales, our observation reveals that the two drought indices show a higher degree of similarity and correlation as timescales increased. In addition, SRI is found to be less variable than SPEI at shorter timescales and it shows an obvious hydrologic delay of about 1-2 months in response to SPEI at timescales > 12 months. Due to hydrologic detention of subsurface soil moisture, shallow groundwater and perhaps reservoir storage, a 2-month timescale of SPEI is found to be more appropriate for river discharge monitoring, especially for those rivers with similar drainage area, climate and geographical conditions as in this study region.
|
|
| 3. |
- Ye, Xuchun, et al.
(författare)
-
Variation of reference evapotranspiration and its contributing climatic factors in the Poyang Lake catchment, China
- 2014
-
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 28:25, s. 6151-6162
-
Tidskriftsartikel (refereegranskat)abstract
- By using linear regression (parametric), Mann–Kendall (nonparametric) and attribution analysis methods, this study systematically analysed the changing properties of reference evapotranspiration (ETr) calculated using the Penman–Monteith method over the Poyang Lake catchment during 1960–2008 and investigated the contribution of major climatic variables to ETr changes and their temporal evolution. Generally, a significant decreasing trend of annual ETr is found in the catchment. The decrease of annual ETr in the Poyang Lake basin is mostly affected by the decline of summer ETr. Over the study period, climatic variables, i.e. sunshine duration (SD), relative humidity (RH), wind speed (WS) and vapour pressure all showed decreasing trends, whereas mean daily temperature (DT) increased significantly. Multivariate regression analysis indicated that SD is the most sensitive climatic variable to the variability of ETr on annual basis, followed by RH, WS and DT, whereas the effect of vapour pressure is obscure. Although recent warming trend and decrease of relative humidity over the catchment could have increased ETr, the combined effect of shortened SD and reduced WS negated the effect and caused significant decrease of ETr. Our investigation reveals that the relative contributions of climatic variables to ETr are temporally unstable and vary considerably with large fluctuation. In consideration of the changes of climatic variables over time, further analysis indicated that changes of mean annual ETr in 1970–2008 were primarily affected by SD followed by WS, RH and DT with reference to 1960s. However, WS became the predominant factor during the period 2000–2008 compared with reference period 1960s, and followed by SD.
|
|
