Observed trends and relationships between ENSO and standardized hydrometeorological drought indices in central Chile

Abstract

Droughts are natural phenomena that severely affect socio economic and ecological systems. In Chile, population and economic activities are highly concentrated in its central region (i.e. between latitudes 29 S and 40 S), which periodically suffers from severe droughts affecting agriculture, hydropower, and mining. Understanding the dynamics of droughts and large-scale atmospheric processes that influence the occurrence of dry spells is essential for forecasting and efficient early detection of drought events. Central Chile's climate is marked by a significant El Niño Southern Oscillation (ENSO) influence that might help to better characterize droughts as well as to identify the effects of ENSO on the spatial and temporal characteristics of meteorological and hydrological droughts in the region. We analysed the behaviour of the Standardized Precipitation Evapotranspiration Index (SPEI) and Standardized Streamflow Index (SSI) time series for 6-month accumulation periods over the austral winter and summer seasons. Multiple linear regression (MLR) and Generalized Linear Models (GLM) showed a significant ENSO influence on dry events for SPEI-6 and SSI-6 during winter and summer. We found that the magnitude of correlation between ENSO and SPEI-6 has changed over the last decades becoming weaker in winter periods and increasing in spring summer periods. Increasing trends in meteorological and hydrological drought events were also identified, along all latitudes, with significant trends during winter in the southern latitudes, and during summer in the semi-arid and Mediterranean zones. These results indicate that drought mitigation actions and policies are necessary to overcome their adverse effects. Given the monthly persistence of ENSO and its relationship to drought indices, there are opportunities for drought monitoring and seasonal forecasting that could become part of national drought management systems.

Spatial and temporal characteristics of drought and its correlation with climate indices in Northeast China

“…It has a great impact on global climate change. There is a significant influence of ENSO on the variation of SPEI in Chile [ 57 ].The variation of ENSO can affect rainfall in Northern China and the development of drought. The Southern Oscillation is the atmospheric component of El Niño and SOI can be used to describe ENSO.…”

Temporal dynamics and the influence of environmental variables on the prevalence of avian influenza virus in main wetlands in central Chile

“…In South America, El Niño–Southern Oscillation (ENSO) is the main driver of interannual climate extremes, which has been associated in recent years with unprecedented warming and a larger extent of extreme drought in areas such as Amazonia (Jiménez‐Muñoz et al., 2016). Central Chile’s climate is also marked by a significant ENSO influence, which has been linked to the current drought indices in the country (Oertel et al., 2020). This ENSO effect, combined with human extraction activities, could be affecting the flooded area of the wetlands.…”

Daily and seasonal variation of the surface temperature lapse rate and 0°C isotherm height in the western subtropical Andes

“…This region exhibits substantial year‐to‐year variability with a SD to mean ratio of about 0.3 (Garreaud et al ., 2017; their Figure 1). Such interannual variability is largely modulated by the El Niño Southern Oscillation (ENSO): wet winters tend to occur during El Niño years while droughts are more frequent during La Niña years (Montecinos and Aceituno, 2003; Oertel et al ., 2020). Drier than normal conditions, however, have prevailed during the last decade (the central Chile mega drought, Garreaud et al ., 2017) under ENSO‐neutral conditions signalling the early effects of the climate change in this region.…”