Abstract
Abstract. Differences between meteorological and hydrological droughts could reflect the regional water consumption by both natural elements and human water-use. The connections between these two drought types were analyzed using the Standardized Precipitation Evapotranspiration Index (SPEI) and Standardized Streamflow Index (SSI), respectively. In a typical semi-arid basin of the middle Yellow River (Qingjianhe River basin), annual precipitation and air temperature showed significantly downward and upward trends, respectively, with the rates of −2.37 mm yr−1 and 0.03 ∘C yr−1 (1961–2007). Under their synthetic effects, water balance variable (represented by SPEI) showed obviously downward (drying) trend at both upstream and whole basin areas. For the spatial variability of precipitation, air temperature and the calculated SPEI, both upstream and downstream areas experienced very similar change characteristics. Results also suggested that the Qingjianhe River basin experienced near normal condition during the study period. As a whole, this semi-arid basin mainly had the meteorological drought episodes in the mid-1960s, late-1990s and the 2000s depicted by 12-month SPEI. The drying trend could also be depicted by the hydrological drought index (12-month SSI) at both upstream and downstream stations (Zichang and Yanchuan), but the decreasing trends were not significant. A correlation analysis showed that hydrological system responds rapidly to the change of meteorological conditions in this semi-arid region. This finding could be an useful implication to drought research for those semi-arid basins with intensive human activities.
Highlights
In recent decades, frequently occurred drought disaster has significant impacts on industrial and agricultural production, human’s livelihood and ecological environmental protection (Mishra and Singh, 2010)
Trend analyses for precipitation and air temperature were performed for Zichang and Yanchuan sub-basins to understand the evolutions of drought episodes with the effect of climate change
The Qingjianhe River basin experienced a near normal condition during the whole study period. This region mainly had the meteorological drought episodes in the mid-1960s, late-1990s and the 2000s depicted by 12-month Standardized Precipitation Evapotranspiration Index (SPEI)
Summary
Frequently occurred drought disaster has significant impacts on industrial and agricultural production, human’s livelihood and ecological environmental protection (Mishra and Singh, 2010). China is one of the countries that experienced frequent and serious drought disaster (Li et al, 2017, 2015; Zou et al, 2005). A large-scale drought occurred in 2000 spread to 20 provinces of China, resulting in substantial economic losses. More than 12 provinces of China were affected by the 2009 drought event, and especially in some northern provinces, the drought degree reached an extreme level. In another example, a drought with 100-year return period swept across southwest China during summer 2009 to spring 2010, resulting in a large decrease in most river levels (Lu et al, 2011)
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