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SIO 210: ENSO conclusionDec. 2, 2004
• Interannual variability (end of this lecture + next)– Tropical Pacific: El Nino/Southern Oscillation– Southern Ocean imprint of ENSO– Tropical Atlantic: dipole mode
This powerpoint was prepared for purposes of this lecture and course only. It contains graphics from copyrighted books and journals. Please do not use without acknowledgment of these sources.
ENSO: normal and La Nina conditions
http://www.pmel.noaa.gov/tao/elnino/nino_normal.html
ENSO: El Nino conditions
http://www.pmel.noaa.gov/tao/elnino/nino_normal.html
Map to show location of Tahiti and Darwin
TahitiDarwin
Walker cell: low pressure at Darwin, high pressure at Tahiti Southern Oscillation Index: Tahiti SLP minus Darwin SLP
Southern Oscilllation index (NCEP)
During El Nino:
SOI is low:
Tahiti minus Darwin is low, meaning that the pressure difference between them is reduced.
Therefore the trade winds are weaker during ENSO.
Note that Darwin and Tahiti anomalies are out of phase
El Ninos: low SOI
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/bulletin/index.html
ENSO indices: based on SST.
Most commonly used is the Nino3
or Nino3,4
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/bulletin
SOI and 110°W temperature as of this week
SST imagery - today’s image
Normal conditions in the tropical Pacific
El Nino conditions in the tropical pacific
Tropical Pacific this week
TAO Project Office PMEL/NOAA
Temperature - mean and anomalies along the equator
November 2002: El Nino November 2004: weak El Nino
Time series: SST at equator
El Nino
La Nina
SST and zonal wind anomalies, equator
SST and dynamic height anomalies, equator
El Nino-La Nina surface height
(NASA altimetry)
http://topex-www.jpl.nasa.gov/science/el-nino.html
ENSO sea surface height anomaly
http://www.osdpd.noaa.gov/
La Nina sea surface height anomaly
http://www.osdpd.noaa.gov/
This month’s surface height
(altimetry):El Nino is
not developing strongly
http://topex-www.jpl.nasa.gov/science/el-nino.html
Sea level pressure and anomalies NCEP October 2004
SST anomalies October 2004 NCEP
SST anomalies time series NCEP
ENSO - long time series of Nino3 index
Very long time series of ENSO: Kim Cobb et al. Based on corals.
Tool: Sea surface temperature pattern associated with El Nino/Southern Oscillation
Correlation of SST record at each location with the Southern Oscillation Index
ENSO (SOI) SST and SLP patterns
SOI surface zonal wind and “clouds”
ENSO global precipitation
effects
USA impacts of El Nino and La Nina: temperature
USA impacts of El Nino and La Nina: precipitation
Compare with SW US monsoon: monsoon is pretty much the same pattern as
ENSO
ENSOENSO
monsoonmonsoon
El Nino - where are we right now?
• An El Nino event is building, and predictions of this winter’s conditions in N. America are related to it.
El NinoWe are in a weak El Nino pattern now.
NOAA Climate Prediction Center winter 2004-2005 patterns prediction:
Figure 5. Seasonal U. S. temperature (left) and precipitation (right) outlooks for December 2004-February 2005. Outlooks prepared in mid-September 2004 reflect a blend of ENSO-related impacts and long-term trends.
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/
warm dry
coolwet
El Nino
Great websites:http://www.pmel.noaa.gov/tao/elnino/nino-home.html
http://topex-www.jpl.nasa.gov/science/el-nino.html