Using the SPEI to Assess Recent Climate Change in the Yarlung Zangbo River Basin, South Tibet

Abstract

Abstract:The Yarlung Zangbo River (YZR) is the largest river system in the Tibetan Plateau, and its basin is one of the centers of human economic activity in Tibet. Large uncertainties exist in several previous climate change studies in this basin because of limited climate observations. In this paper, we used a meteorological drought index (Standardized Precipitation Evapotranspiration Index, SPEI) and a newly-released gridded climate forcing dataset based on high-quality climate station data to re-evaluate climate change in the YZR Basin during the period of 1961-2014. Results showed that precipitation experienced a statistically insignificant increasing trend at a rate of 6.32 mm/10 years, and its annual mean was 512.40 mm. The basin was sensitive to climate change in terms of the air temperature that significantly increased at the rate of 0.32 °C/10 years. This warming rate was obviously larger than that in many other regions. Analysis of SPEI showed that the basin had no obvious statistical trends in the number of dry/wet episodes, but the severity of dry episode aggravated in terms of duration and magnitude. This study provides a reliable analysis of OPEN ACCESSWater 2015, 7 5475 climate change in the YZR Basin, and suggests this large Tibetan river basin is sensitive to climate change.

Characterization of drought in the Kerio Valley Basin, Kenya using the Standardized Precipitation Evapotranspiration Index: 1960−2016

“…The standardized Z scores obtained from the MK test are useful indicators in identifying trends in drought events. Positive Z scores indicate an increasing trend, while negative Z scores indicate a decreasing trend (Li et al ., ). The MK test, however, requires the data to be serially independent (Wang et al ., ).…”

“…The Standardized Precipitation Evapotranspiration Index (SPEI) The Standardized Precipitation Evapotranspiration Index (SPEI) was used to evaluate agricultural and hydrological drought in the Kerio Valley basin and the surrounding areas. The SPEI has been widely used to assess drought variability, drought reconstruction, drought atmospheric mechanisms, climate change, and drought impacts on hydrological, agricultural, and ecological systems (Li et al, 2012;Vicente-Serrano et al, 2013;Beguería et al, 2014;Yu et al, 2014;Chen & Sun, 2015;Li et al, 2015;Stagge et al, 2015;Vicente-Serrano et al, 2015;Wang et al, 2015).…”

“…The MK test which checks for the nonlinear trends within a time series (Mann, 1945;Kendall, 1975) has been widely used to identify trends in drought occurrence (e.g. Paulo et al, 2012;Yu et al, 2014;Li et al, 2015;Tan et al, 2015;Wang et al, 2017). The standardized Z scores obtained from the MK test are useful indicators in identifying trends in drought events.…”

Analysis of the Inhomogeneous Effect of Different Meteorological Trends on Drought: An Example from Continental Croatia

“…Table 2. Limit values for the standardised precipitation evapotranspiration index (SPEI) [36]. Run theory can be used to define drought severity, duration, and intensity.…”

Runoff Dynamics and Associated Multi-Scale Responses to Climate Changes in the Middle Reach of the Yarlung Zangbo River Basin, China

“…Based on the observations from 2472 national meteorological stations, the CTAP and CPAP were produced by the Thin Plate Spline (TPS) and climatology-based Optimal Interpolation (OI) technique, respectively [8,19]. All the observations used in CTAP and CPAP have undergone strict quality control (QC), including the extrema detection, internal consistency check, and spatial consistency check, before the interpolation operation [20,21].…”