Largest study of Asia’s rivers unearths 800 years of paleoclimate patterns
813 years of annual river discharge at 62 stations, 41 rivers in 16 countries, from 1200 to 2012. That is what researchers at the Singapore University of Technology and Design (SUTD) produced after two years of research in order to better understand past climate patterns of the Asian Monsoon region.
Home to many populous river basins, including ten of the world’s biggest rivers (Figure 1), the Asian Monsoon region provides water, energy, and food for more than three billion people. This makes it crucial for us to understand past climate patterns so that we can better predict long term changes in the water cycle and the impact they will have on the water supply.
To reconstruct histories of river discharge, the researchers relied on tree rings. An earlier study by Cook et al. (2010) developed an extensive network of tree ring data sites in Asia and created a paleodrought record called the Monsoon Asia Drought Atlas (MADA). SUTD researchers used the MADA as an input for their river discharge model.
They developed an innovative procedure to select the most relevant subset of the MADA for each river based on hydroclimatic similarity. This procedure allowed the model to extract the most important climate signals that influence river discharge from the underlying tree ring data.
“Our results reveal that rivers in Asia behave in a coherent pattern. Large droughts and major pluvial periods have often occurred simultaneously in adjacent or nearby basins. Sometimes, droughts stretched as far as from the Godavari in India to the Mekong in Southeast Asia (Figure 2). This has important implications for water management, especially when a country’s economy depends on multiple river basins, like in the case of Thailand,” explained first author Nguyen Tan Thai Hung, a Ph.D. student from SUTD.