Impacts of Climate Change on Blue and Green Water Resources in the Middle and Upper Yarlung Zangbo River, China

Abstract

The Yarlung Zangbo River is the largest river on the Tibetan Plateau and a major international river in South Asia. Changes in the blue and green water resources in its basin are of great importance to the surrounding local and Asian regions in the context of global warming. This research used the Soil and Water Assessment Tool model to estimate blue and green flows (BWF and GWF) and analyze the spatial-temporal distribution characteristics under different hypothetical climate change scenarios. The results show that (1) the multi-year average BWF in the middle and upper reaches of the Yarlung Zangbo River Basin is 176.2 mm, the GWF is 213.1 mm, and the difference between precipitation and total water resources is only 5.4 mm; (2) both BWF and GWF in this basin showed a slightly increasing trend from 1980 to 2010, but the distribution of subbasins from upstream to downstream is decreasing; and (3) GWF has a positive correlation with both precipitation and temperature, but BWF only increases with precipitation and decreases with increasing temperature. Moreover, the change in blue and green water resources is more sensitive to the changes in precipitation than to changes in the temperature.

Estimation of Biogas Generated in Two Landfills in South-Central Ecuador

“…The LandGEM biogas model version 3.0, is a Microsoft Excel application that uses a first-order equation to estimate the total volume of biogas, CH 4 , CO 2 and other NMOC gases generated [18,[29][30][31][32][33][34][35]. The equation used by the model is detailed below in Equation (1):…”

“…In order to calculate the power to produce electrical energy, the principle of cogeneration using internal combustion engines (ICM) was used, due to its low cost per kW/USD and high efficiency [15,20,32]. It has a biogas flow rate of approximately 300 to 1100 cfm, and it is calculated by the following equation [20][21][22]32,33]:…”

“…Hence, the importance of taking advantage of these gases in the production of electrical energy is demonstrated in the studies performed at the global and national level as detailed in Table 5 [9,[39][40][41]. Therefore, to minimize the impacts related to global warming and climate change, the biogas generated in landfills may be used as an energy source to produce electricity [22,32,33]. Therefore, regarding the biogas produced from the decomposition of MSW, it is fundamental to calculate the amount and concentration of biogas, through the application of the LandGEM Landfill Gas Emission model version 3.03, in order to estimate the volume and the concentration of biogas generated in the Pichacay and Las Iguanas sanitary landfill over a period of 32 years.…”

“…Therefore, the model may not be valid since the concentrations are out of the given range. However, for future biogas estimates, we will compare with other models to develop our own model considering the climatic conditions, the characteristics of the waste and concentrations of the gases typical of the sector where the landfill is located [16,32,53,54]. Hence, in the results of works performed in 2011, the potential for electrical production of biogas, generated in the Pichacay landfill, calculated through theoretical models conducted by the (EPA), assuming a concentration of 50% CH 4 and 50% CO 2 starting in 2009, it has been estimated that it will reach a higher point of biogas generation in 2019, with 1152 m 3 /h with a maximum capacity of 1.90 MW.…”

Interannual variation of midsummer precipitation in the middle reaches of Yarlung Zangbo River and its possible mechanisms

“…Since Yarlung Zangbo River (YZR) is one of the highest rivers on Earth and originates from the Jema Yangtse Glacier on the northern slope of Himalayas in the southern TP, its hydroclimatic processes are of great significance to the climate and ecological environment of the TP (Huo et al, 2021; Zeng et al, 2018). As a population gathering area in the Inner TP, YZR is not only the main source of fresh water for local industry, agriculture and residents, but also an important reservoir of water resources.…”