The pantropical response of soil moisture to El Niño

Kurt C. Solander, Brent D. Newman, Alessandro Carioca De Araujo, Holly R. Barnard, Z. Carter Berry, Damien Bonal, Mario Bretfeld, Benoit Burban, Luiz Antonio Candido, Rolando Célleri, Jeffery Q. Chambers, Bradley O. Christoffersen, Matteo Detto, Wouter A. Dorigo, Brent E. Ewers, Savio José Filgueiras Ferreira, Alexander Knohl, L. Ruby Leung, Nate G. McDowell, Gretchen R. MillerMaria Terezinha Ferreira Monteiro, Georgianne W. Moore, Robinson Negron-Juarez, Scott R. Saleska, Christian Stiegler, Javier Tomasella, Chonggang Xu

Research output: Contribution to journalArticle

Abstract

The 2015-2016 El Niño event ranks as one of the most severe on record in terms of the magnitude and extent of sea surface temperature (SST) anomalies generated in the tropical Pacific Ocean. Corresponding global impacts on the climate were expected to rival, or even surpass, those of the 1997-1998 severe El Niño event, which had SST anomalies that were similar in size. However, the 2015-2016 event failed to meet expectations for hydrologic change in many areas, including those expected to receive well above normal precipitation. To better understand how climate anomalies during an El Niño event impact soil moisture, we investigate changes in soil moisture in the humid tropics (between <span classCombining double low line"inline-formula">±25</span><span classCombining double low line"inline-formula">ĝ&circ; </span>) during the three most recent super El Niño events of 1982-1983, 1997-1998 and 2015-2016, using data from the Global Land Data Assimilation System (GLDAS). First, we use in situ soil moisture observations obtained from 16 sites across five continents to validate and bias-correct estimates from GLDAS (<span classCombining double low line"inline-formula">r2Combining double low line0.54</span>). Next, we apply a <span classCombining double low line"inline-formula">k</span>-means cluster analysis to the soil moisture estimates during the El Niño mature phase, resulting in four groups of clustered data. The strongest and most consistent decreases in soil moisture occur in the Amazon basin and maritime southeastern Asia, while the most consistent increases occur over eastern Africa. In addition, we compare changes in soil moisture to both precipitation and evapotranspiration, which showed a lack of agreement in the direction of change between these variables and soil moisture most prominently in the southern Amazon basin, the Sahel and mainland southeastern Asia. Our results can be used to improve estimates of spatiotemporal differences in El Niño impacts on soil moisture in tropical hydrology and ecosystem models at multiple scales.

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Original languageEnglish (US)
Pages (from-to)2303-2322
Number of pages20
JournalHydrology and Earth System Sciences
Volume24
Issue number5
DOIs
StatePublished - May 11 2020

ASJC Scopus subject areas

  • Water Science and Technology
  • Earth and Planetary Sciences (miscellaneous)

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    Solander, K. C., Newman, B. D., Carioca De Araujo, A., Barnard, H. R., Berry, Z. C., Bonal, D., Bretfeld, M., Burban, B., Candido, L. A., Célleri, R., Chambers, J. Q., Christoffersen, B. O., Detto, M., Dorigo, W. A., Ewers, B. E., Ferreira, S. J. F., Knohl, A., Leung, L. R., McDowell, N. G., ... Xu, C. (2020). The pantropical response of soil moisture to El Niño. Hydrology and Earth System Sciences, 24(5), 2303-2322. https://doi.org/10.5194/hess-24-2303-2020