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

El Niño Southern Oscillation (ENSO) El Niño: –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: –Cool ocean temperatures in East Pacific –Trade winds strengthen –Low air surface pressure in the western Pacific

ENSO Demonstration

SOI: An index of ENSO William Kessler, NOAA oi-shade-ncep-b.gif ENSO/SOI Blue: La Niña Red: El Niño

Huanghe (Yellow River) Introduction (modified from Wang et al., 2006)

Activity Calculate SOI Plot SOI Answer the questions in groups Class discussion

Huanghe (Yellow River) Class Discussion (modified from Wang et al., 2006) Q n =0.284P R 2 =0.595 n=51

Huanghe (Yellow River) Class Discussion (Modified from Wang et al., 2006)

Huanghe (Yellow River) Class Discussion See Figure 5. (Wang et al., 2006) doi: /j.gloplacha 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: /j.gloplacha

Huanghe (Yellow River) and ENSO ENSO events directly affect the regional precipitation in the river basin. –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 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, 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, L 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, International Research Institute for Climate and Society, Columbia University: El Nino and the Science of Climate Prediction: Walker Circulation Cell: NOAA El Nino activity: ENSO Index from NOAA back to 1871: Australian Government Bureau of Meterology SOI data: