Transcript ENSO in the Anthropocene

El Niño-Southern Oscillation
(ENSO) and the Huanghe
Using the ENSO index, and river water
and sediment discharge to understand
changing climate, and human impacts
Objective
• Walker Circulation Cell
• ENSO
• La Niña, Normal and El Niño conditions
– Demonstration
– Group experiment
• ENSO index plots
• The Huanghe
• Human impacts
Walker Circulation Cell
http://en.wikipedia.org/wiki/File:LaNina.png
El Niño Southern Oscillation
(ENSO)
El Niño:
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Warm ocean temp. in East Pacific
Rise in surface pressure of Indian Ocean,
Indonesia and Australia
Fall in air pressure over Tahiti (and the
rest of the central and eastern Pacific)
Trade winds weaken
Warm air rises near Peru, causing rain in
nearby Peruvian deserts
Extensive drought in western Pacific
La Niña:
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Cool ocean temperatures in East Pacific
Trade winds strengthen
Low air surface pressure in the western Pacific
http://www.public.asu.edu/~edimaggi/Pictures/ElNinoLaNinaFigure.jpg
www.bom.gov.au
ENSO Demonstration
http://www.pmel.noaa.gov/tao/elnino/gif/reynolds/nancy4.gif
SOI: An index of ENSO
ENSO/SOI
Blue: La Niña
Red: El Niño
William Kessler, NOAA
http://faculty.washington.edu/kessler/ENSO/s
oi-shade-ncep-b.gif
Huanghe (Yellow River)
Introduction
(modified from Wang et al., 2006)
Activity
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Calculate SOI
Plot SOI
Answer the questions in groups
Class discussion
Huanghe (Yellow River)
Class Discussion
Qn=0.284P-50.54
R2=0.595 n=51
(modified from Wang et al., 2006)
Huanghe (Yellow River)
Class Discussion
(Modified from Wang et al., 2006)
Huanghe (Yellow River)
Class Discussion
See Figure 5. (Wang et al., 2006) doi:10.1016/j.gloplacha.2006.01.005
Locations of two reservoirs along the Huanghe. This slide could be used
for a class discussion of the answers to question 5 and 6.
Huanghe (Yellow River) and ENSO
Optional: Additional information that can be used to discuss the changes
in natural vs. measured river water discharge in different time periods
(top), and also looking at monthly water consumption before (middle)
and after (bottom) dam construction.
See Figure 7. (Wang et al., 2006) doi:10.1016/j.gloplacha.2006.01.005
Huanghe (Yellow River) and ENSO
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ENSO events directly affect the regional precipitation in the river basin.
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Moderate to strong El Niño correspond to low precipitation in the area
51% decrease in river discharge to the sea because of strong ENSO
Large dams and reservoirs shifted the seasonal and annual distribution patterns of water
discharge
Resulted in water scarcity of the Huanghe
River mouth and receiving basin (Bohai Sea) negatively impacted.
Bohai Sea Salinity increased by 2 ppt.
Changes in sediment discharge = trapping effect of the dams and reservoirs
Significant changes in delta morphology, retreating shorelines, coastal erosion and delta
degradation
References & More Information
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Wang, H., Z. Yang, Y. Saito, J.P. Lui & X. Sun, 2006, Interannual and seasonal variation of the Huanghe
(Yellow River) water discharge over the past 50 years: Connections to impacts from ENSO events and
dams, Global and Planetary Change, 50, 212-225.
Wang, L., W. Chen & R. Huang, 2008, Interdecadal modulation of PDO on the impact of ENSO on the
east Asian winter monsoon, Geophysical Research Letters, 35, L20702.
Ziemke, J.R., S. Chandra, L.D. Oman & P.K. Bhartia, 2010, A new ENSO index derived from satellite
measurements of column ozone, Atmospheric Chemistry and Physics Discussions, 10, 2859-2887.
http://www.atmos-chem-phys-discuss.net/10/2859/2010/acpd-10-2859-2010.pdf
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International Research Institute for Climate and Society, Columbia University:
http://iri.columbia.edu/climate/ENSO/background/reference.html
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El Nino and the Science of Climate Prediction:
http://www.gcrio.org/CONSEQUENCES/vol5no2/article_1.html
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Walker Circulation Cell: http://www.youtube.com/watch?v=FPjtl943Taw
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NOAA El Nino activity: http://www.oar.noaa.gov/k12/html/elnino2.html
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ENSO Index from NOAA back to 1871: http://www.esrl.noaa.gov/psd/enso/mei.ext/
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Australian Government Bureau of Meterology SOI data:
http://www.bom.gov.au/climate/current/soihtm1.shtml