El Niño–Southern Oscillation incidence over long dry sequences and their impact on soil water storage in Argentina

Abstract

The deficit of daily precipitation, persistent over time (long dry sequences [LDS]), causes economic losses in the east–northeast of Argentina where agriculture production is the main economic activity. For this reason, an improvement in the seasonal prediction of the frequency of precipitation is required. Among several forcings influencing the region of study, El Niño–Southern Oscillation (ENSO) has been identified as responsible for a great part of the inter‐annual variability of precipitation. Therefore, in this study, we assess the ENSO signal on LDS and the response of soil water storage under the different phases. In order to assess this issue, daily data were used from 30 meteorological stations. Based on this information, dry sequences were quantified considering a dry day when the accumulated precipitation of two consecutive days was lower than 5 mm. From the dry sequences, two different thresholds were used to identify LDS. On one hand, the 85th percentile was selected as a spatially variable threshold and, on the other hand, 15‐day length was used as a fixed one. Based on this selection, the severity and the number of LDS were analysed. In general terms, La Niña (El Niño) phase presents higher (lower) severity and higher (lower) probability in the occurrence of more than one LDS per season, except in winter. This result is in concordance with negative (positive) anomalies of accumulated precipitation under La Niña (El Niño) phase. Regarding the impact on the water balance, soil water storage responds to accumulated precipitation anomalies in all the seasons.

Characterization of the seasonal variation of soil moisture in Argentina

“…This model has been proven to have a very good fit with observed data (Spennemann et al ., 2020; Veliz et al ., 2016) and has been used in Argentina for the estimation of soil moisture with different objectives (Pántano et al ., 2017; Pinto et al ., 2017; Penalba et al ., 2019).…”

CRONOSOJA: a daily time-step hierarchical model predicting soybean development across maturity groups in the Southern Cone

“…The available soil water is the difference between the amount of SM t and the amount of PWP. This model has been proven to have a very good fit with observed data (Fernández-Long et al, 2018;Spennemann et al, 2020) and has been used in Argentina for the estimation of soil moisture with different objectives (Fernández-Long et al, 2021;Penalba et al, 2019;Peretti et al, 2023;Pinto et al, 2017).…”

El Niño Southern Oscillation‐related precipitation anomaly variability over eastern subtropical South America: Atypical precipitation seasons

“…LPB is key for crop production in the encompassed countries, becoming one of the major food production regions in the world (Penalba and Vargas, 2008). Because crop production depends on rainfall and its variability, several studies have been carried out to understand precipitation variability over the region (e.g., Kousky and Kayano, 1994; Pisciottano et al ., 1994; Grimm et al ., 1998; 2000; Grimm, 2003, 2004; Vera et al ., 2006; Grimm and Zilli, 2009; Grimm and Tedeschi, 2009; Li et al ., 2011; González et al ., 2012; Marengo et al ., 2012; Tedeschi et al ., 2013; 2016; Rodrigues and McPhaden, 2014; Grimm and Saboia, 2015; Tedeschi and Collins, 2016; Penalba et al ., 2019). The main forcing driving inter‐annual precipitation variability over South America is El Niño Southern Oscillation (ENSO; Grimm, 2011).…”