Investigation of the Variability and Implications of Meteorological Dry/Wet Conditions in the Poyang Lake Catchment, China, during the Period 1960–2010

Abstract

This paper presents a quantitative investigation of the variability of meteorological dry/wet conditions of the Poyang Lake catchment during 1960-2010 by using the standardized precipitation-evapotranspiration index (SPEI) based on daily observations of 14 meteorological stations across the catchment. Extending from previous studies, the background of the encounter and overlap of multitimescales of meteorological dry/wet episodes for several severe drought and flood events were discussed. In addition, the possible impacts of temperature changes on dry/wet variability were also examined by the comparison of SPEI and standardized precipitation index (SPI) variations at multitimescales during the study period. Major results show that the occurrence of dry/wet condition has become increasingly frequent in the recent two decades, especially the extreme wet episodes in 1990s and the extreme dry episodes in 2000s. Historically, the encounter and overlap of multitimescales of meteorological dry/wet episodes plays an important role in the occurrence of several severe drought and flood events. The study concluded that the impact of temperature anomaly to the dry/wet variability cannot be neglected.

Analysis of Dry/Wet Variations in the Poyang Lake Basin Using Standardized Precipitation Evapotranspiration Index Based on Two Potential Evapotranspiration Algorithms

“…For wet episode calculated from SPEI_pm and SPEI_th, the most frequent occurrence was in winter, varying from 18% to 20%, and the second-highest frequency occurred in spring with the same frequency of 18.8%. The results here generally concur with Ye et al [53]. Ye et al showed that the most frequent occurrence of wet episode was in November, December, and February.…”

Responses of Water Level in China’s Largest Freshwater Lake to the Meteorological Drought Index (SPEI) in the Past Five Decades

“…The basin contains five main subbasins: the Ganjiang, Fuhe, Xinjiang, Raohe, and Xiushui River Basins (Figure 2). Poyang Lake (115°49′-116°46′ E, 28°24′-29°46′ N), which is China's largest freshwater lake, mainly receives water from these five rivers before discharging into the Yangtze River at Hukou [19]. The topography in the Poyang Lake Basin is quite complex, which consists of mountainous areas, subordinate hills, and alluvial plains.…”

“…However, the SPI only considers the influence of precipitation. In the context of global change, rising temperature has become one of the important factors aggravating drought processes [19]. Therefore, the objective characterization of drought conditions requires us to consider the joint effects of precipitation and temperature changes.…”

“…However, due to the uneven distribution of seasonal precipitation, the Poyang Lake Basin has become one of the most flood-and drought-prone regions in China. Over the past several decades, both droughts and floods have occurred frequently in this basin, causing enormous damage to the environment and the agricultural development [19,[27][28][29]. Poyang Lake, which is located in this basin, is the largest freshwater lake in China, and it is one of the first lakes in China to be included in the Ramsar Convention's List of International Wetlands [30].…”

The Use of SPEI and TVDI to Assess Temporal-Spatial Variations in Drought Conditions in the Middle and Lower Reaches of the Yangtze River Basin, China

“…In this study, the SPEI, which is calculated as the difference between precipitation and potential evapotranspiration (PET), is used to describe the severity of drought conditions [26,37,38]. e ornthwaite and Penman-Monteith approaches are widely applied in the calculation of PET [39,40].…”