1
Trade Winds in Equatorial Pacific
2
ITCZ Location
July
January
ITCZ
ITCZ
3
Equatorial Divergence vs Subtropical Convergence
upwelling downwelling
4
Trade Winds Cause Variations in Sea Surface
Height
ITCZ
ITCZ
SSH
5
Meridional Trends in Trade Wind Strength, Sea
Surface Height, and Currents in the
Equatorial Pacific
TradeWind Speed
Surface Current Direction
SSH (cm)
Depth (m)
HPG
westward
eastward
ITCZ
I------Conv------IDivIConI-Div-I---Conv---I
6
Zonal (E-W) Trend in Sea
Surface Height
Zonal (east-west) trend in Sea Surface Height
Wind Stress
SSH
Temperature(+ = depth of EUC)
7
Equatorial Undercurrent
A
A6
EUC
Velocity (m/s)
Temperature (ºC)
Velocity Cross Sections
8
SST in Equatorial Pacific
ºC
9
Surface Nitrate Distribution
10
Photosynthesis Rates in Surface Ocean
11
Cross Sections in
the Equatorial
Pacific
Temp
Salinity
Oxygen
Phosphate
Zonal Vel.
12
Effect of El Nino on Anchovy Catch
El Ninos in red
13
Array of Buoys Monitored by NOAA for Wind Speed, SST, Salinity, Current Velocities
The best instrumented region of the world’s ocean
14
Sea Surface Temperature Changes
15
Weakening of Trade Winds during El Nino
Normal
El Nino
16
Atmospheric Circulation and
Precipitation Changes during
El Nino
Normal
El Nino
17
SST and Chlorophyll during El Nino
El Nino
Normal
9
18
Animation of SST Anomalies during El Nino of 1997
• http://www.cdc.noaa.gov/map/clim/sst_olr/old_sst/sst_9798_anim.shtml
19
History of Southern Oscillation Index(and correlation with El Nino events)
ENSO Index
20
Change in Zonal Atmospheric
Circulation in Equatorial Pacific
21
Global Weather Anomalies during El Nino
22
Global Weather Anomalies during La Nino
23
El Nino Effects on US Temperatures (Winter)
Warmer in northern midwest and cooler in south
24
El Nino Effects on US Precipitation (Winter)
Wetter in southeast US
25
El Nino Effects on Jet Stream
position and US Weather
26
Currently El Nino Conditions (Nov 2009)
SST anomaly is currently 1-4ºC warmer than normal (avg.= 1.5ºC).
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