Abstract
Abstract. An increasingly uneven distribution of hydrometeorological factors related to climate change has been detected by global climate models (GCMs) in which the pattern of changes in water availability is commonly described by the phrase dry gets drier, wet gets wetter (DDWW). However, the DDWW pattern is dominated by oceanic areas; recent studies based on both observed and modelled data have failed to verify the DDWW pattern on land. This study confirms the existence of a new DDWW pattern in China after analysing the observed streamflow data from 291 Chinese catchments from 1956 to 2000, which reveal that the distribution of water resources has become increasingly uneven since the 1950s. This pattern can be more accurately described as drier regions are more likely to become drier, whereas wetter regions are more likely to become wetter. Based on a framework derived from the Budyko hypothesis, this study estimates runoff trends via observations of precipitation (P) and potential evapotranspiration (Ep) and predicts the future trends from 2001 to 2050 according to the projections of five GCMs from the Coupled Model Intercomparison Project Phase 5 (CMIP5) under three scenarios: RCP2.6, RCP4.5, and RCP8.5. The results show that this framework has a good performance for estimating runoff trends; such changes in P play the most significant role. Most areas of China, including more than 60 % of catchments, will experience water resource shortages under the projected climate changes. Despite the differences among the predicted results of the different models, the DDWW pattern does not hold in the projections regardless of the model used. Nevertheless, this conclusion remains tentative owing to the large uncertainties in the GCM outputs.
Highlights
Terrestrial water availability is critical to human lives and economic activities (Milly et al, 2005)
The slight decrease in d to 0.79 in the last interval can be attributed to the small sample size of this interval; the number of catchments getting drier is equal in intervals 5 and 6 (Table 2). These results indicate a new DDWW pattern, which emphasizes the fact that the distribution of water resources has become increasingly uneven in China since the 1950s
Based on a Budyko-based framework, our findings suggest that climate change is the main factor of the historical runoff trends in China and that kP is the most significant factor associated with climate change
Summary
Terrestrial water availability is critical to human lives and economic activities (Milly et al, 2005). This trend results in probable enhancement of hydrological extremes such as floods and droughts This response is known as the “rich-get-richer mechanism” (Chou and Neelin, 2004), from which follow-up studies have derived diverse summaries of different elements such as “dry gets drier, wet gets wetter” for precipitation (P ) (Allan et al, 2010) and precipitation minus evapotranspiration (P − E) (Held and Soden, 2006), “wet season gets wetter, dry season gets drier” for seasonal precipitation (Chou et al, 2013), and “fresh gets fresher, salty gets saltier” for ocean salinity (Durack et al, 2012; Roderick et al, 2014). These mechanisms have attracted a significant amount of attention in ex-
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
