New data from river basins in the Asian Monsoon region reconstruct the histories of annual river discharge from 41 rivers using dendrochronology. The study provides a record of 813 years of data that can help scientists to better understand the climate patterns of some of the world’s largest rivers.
The data is published in a study in Water Resources Research by researchers at the Singapore University of Technology and Design (SUTD). The team created a model to look at river discharge from 1200-2012 based on data from a previously published paleodrought record called the Monsoon Asia Drought Atlas (MADA).
"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. 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.
Another key finding that the study discovered concerned the interactions between Asian rivers and the oceans. While previous investigations have shown how oceanic events like El Niño influence rivers in the Asian Monsoon region by way of atmospheric circulation, this most recent investigation revealed that these interactions are not constant. In fact, the model showed that Asian rivers were much less influenced by the oceans in the first half of the 20th century compared to the 50 years before and 50 years after that time.
The authors comment on the significance of their findings, saying it is imperative to comprehend historical climate patterns in order to understand current and future patterns and make informed decisions.
"This research is of great importance to policymakers; we need to know where and why river discharge changed during the past millennium to make big decisions on water-dependent infrastructure. One such example is the development of the ASEAN Power Grid, conceived to interconnect a system of hydropower, thermoelectric, and renewable energy plants across all ASEAN countries. Our records show that 'mega-droughts' have hit multiple power production sites simultaneously, so we can now use this information to design a grid that is less vulnerable during extreme events," said principal investigator Associate Professor Stefano Galelli.