Effects of El Niño/southern oscillation on simulated phosphorus loading in south Florida

Victoria W. Keener, Keith T. Ingram, Barry Jacobson, James W. Jones

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


The El Niño/Southern Oscillation (ENSO) is a global climate phenomenon with strong effects on Florida's weather patterns. ENSO has been shown to have predictable effects on streamflow, rainfall, and crop yield; however, the relationship between N and P loading and ENSO has not been previously explored. Nutrient loads for a Lake Okeechobee sub-basin for 1965-2001 were simulated with the Watershed Assessment Model (WAM) and compared to measured P loads. The NS coefficients for simulated and measured monthly P loads were 0.73 for the calibration period and 0.63 for the validation period, which indicates "satisfactory" to "good" model performance. With a probable error range (PER) of ±27.8% for measured P loads, the modified NS coefficients increased to 0.94 for the calibration period and 0.93 for the validation period. Results showed that ENSO strongly affected simulated seasonal and monthly phosphorus runoff. El Niño years produced seasonal peak loads of P runoff into Lake Okeechobee significant at the 99% level during the spring (February-April), which indicates dominance of positive load anomalies. La Niña years produced significant seasonal peak loads in the summer (May-July) but with much greater variability in loads. Neutral years exhibited less predictable seasonal loading, although simulated P loads were generally similar to measured long-term means. Nutrient loading patterns during specific ENSO phases were comparable to previously explored precipitation and streamflow patterns in south Florida. This research has potential for use by land and water managers who can add short-term ENSO-based climate forecasts to their toolbox for reducing nutrient runoff.

Original languageEnglish (US)
Pages (from-to)2081-2089
Number of pages9
JournalTransactions of the ASABE
Issue number6
StatePublished - Nov 2007
Externally publishedYes


  • Climate forecast
  • ENSO
  • El Niño
  • Florida
  • Hydrologic modeling
  • Phosphorus
  • Runoff
  • WAM

ASJC Scopus subject areas

  • Forestry
  • Food Science
  • Biomedical Engineering
  • Agronomy and Crop Science
  • Soil Science


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