Peru upwelling (Chl concentration)
Peru Fishery
Normal Peruvian coastal desert Flooded Peruvian dessert during El Niño
Definitions Southern Oscillation Index (SOI): the normalized difference in surface pressure between Tahiti (French Polynesia) and Darwin (Australia): a measure of the strength of the trade winds) El Niño: large scale weakening of the trade winds and warming of the surface layers in the eastern and central equatorial Pacific Ocean La Niña: stronger than normal trade winds and anomalously cold equatorial Pacific sea surface temperatures ENSO: full range of variability observed in the Southern Oscillation Index
Southern Oscillation Index
Tropical Atmospheric Oceanic Project
Equatorial Pacific TAO Moorings
Sea Surface Height
El Ni ñ o Periodicity (~4 years?)
SST SST Anomaly (deviation from average)
SST anomalies off Peru coastline
Southern Oscillation Index
Forecasting ENSO
El Niño – Surface winds
El Nino – increase storms in Southern California
Los Angeles, 1955
La Niña - Floods in Pacific Northwest
ENSO & Precipitation
El Niño & hurricanes Linda 185 mph – 298 km/h September 1997
ENSO & human diseases Dengue or Yellow Fever Viral disease Vector:
Generalities of ENSO El NiñoLa Niña "Southern Oscillation"No "oscillation" Tradewinds failTradewinds increase Reverse flow of airNo reverse flow Elevated SSTDecreased SST Upwelling decreasedUpwelling increased Fish die in Peru Fish thrive (can still be a bad deal if fish prices drop) Dry areas floodedDry areas get drier (e.g., Florida) Wet areas dry upWet areas get flooded (e.g., Oregon)
El Niño La Niña
Spatio-temporal scales of effects on peruvian pelagic fisheries A. Bertrand Time Space Decade Inter-annual MonthSeasonYearDay Ocean Local Regional Basin Stock condition before ENSO Adapted reproduction Fishery pressure Local Upwelling ENSO strength and duration Inter-decadal regime Large scale forcing Small scale forcing
ENSO and pelagic fisheries: regime shift A. Bertrand Chavez et al 2003
(Chavez et al. 2002) A. Bertrand
(Chavez et al. 2002) A. Bertrand
Pacific Decadal Oscillation Warm PhaseCool Phase Wintertime Wind (arrows) and Sea Surface Temp (colors) - Affect the N. Pacific, with secondary signatures in the tropics (opposite for ENSO)
Pacific Decadal Oscillation year duration
A. Bertrand Chavez et al 2003
A. Bertrand Chavez et al 2003