These are the devastating effects of the El Nino and La Nina phenomena – Nation World News

The El Niño-Southern Oscillation (ENSO or ENSO) is The main phenomenon that explains annual variations of climate at the planetary scaleTherefore, it is essential to understand the annual variability of water resources in our region to understand its impact. To do this, a group of researchers from the Faculty of Physical and Mathematical Sciences of the University of Chile identified specific differences between its phases—El Niño and La Niña—primarily based on empirical data on precipitation, temperature and flow in the Chilean basin. using the. Central.

The study, published in the journal Water Resources Research, analyzed 59 basins located between the Tarapacá and Los Lagos regions, which provide water resources for the country’s most populous cities and allow the development of economic activities with high water demand, such as agriculture, power generation, and mining. Compared to La Nina years, during El Niño years “we observed greater rainfall and flow, longer storm duration but with the same frequency, warmer winters and cooler late spring (October–December), flow production in the rainfall regime More efficiency in the basin, and less efficiency in the Snow Basin, explains Diego Hernandez, a researcher at the Advanced Mining Technologies Center (AMTC).

They also verified with simulated data that, although the flow contributed by glaciers shows differences between El Niño and La Niña years, these They fail to affect the annual amount of total flow. “In this way, the study provides a thorough characterization of the effect of ENSO on different components of the water cycle,” he explains.

To better understand the impact on the hydrological cycle, the researchers analyzed the response of mean annual flow to observed changes in precipitation and temperature. “This analysis showed that low-elevation basins presented greater flows due to increased winter temperatures, while higher basins responded with a decrease in flows. Furthermore, in both cases the response was of greater magnitude in those basins.” where evaporative processes predominate.

On the other hand, basins respond with lower flows to the increase in temperature in late spring, which is intensified for basins with dry and warm weather”, explained hydrologist Pablo Mendoza, an academic in the FCFM department of the Department of Civil Engineering. The novelty of the work is to go beyond variations in precipitation and flow to describing anomalies in seasonal temperature induced by ENSO.

Later, It is analyzed how these temperature changes affect the different basins of central Chile. In this sense, the aim of the study is to better understand how the simultaneous variation of precipitation and temperature propagates through the hydrological cycle and affects our rivers, and to address this question we look at the vastness of our region. Rely on diversity”, says Hernandez.

The results allow us to identify in which basins the effect of ENSO is simple and in which it is complex, due to the different hydrological variables that have changed and those investigated in this investigation. “This has practical implications, for example, for the use of climate information in forecasting or hydrological projections in our region,” warns the researcher. The study contributes to improving the understanding of water resources and their processes, which is key to the region’s resilience in future conditions with a changing climate. Research team Diego Hernandez (DIC/AMTC), Pablo Mendoza (DIC/AMTC), Juan Pablo Boissier (CR2/DGF) and Franco Richetti (DIC).