Contemporary Climate Oscillations: ENSO and a case study of the Huanghe River

Nicole Marshall, Steve Kuehl

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At the 2014 Workshop: Bringing NSF MARGINS Research Into the Undergraduate Curriculum, participants conducted a paired review for each mini-lesson in the collection. Prior to the workshop, all mini-lessons had been submitted and pairs of reviewers were assigned. Additional time was allocated at the workshop to complete these reviews.

The pairs of reviewers for each mini-lesson consisted of an author from the same initiative with an author from another GeoPRISMS initiative (e.g., an S2S author paired with an RCL author). Both the mini-lesson author and the peer review author used the rubric developed as part of the On the Cutting Edge project.

The peer reviewer and author discussed the reviewer's comments on the mini-lesson. Authors were encouraged to work on revisions to their mini-lesson based on the feedback they received both at and following the workshop. In addition, a pedagogical expert met with each initiative team to discuss the mini-lesson revision plans and ensure strong learning goals and assessment strategies.


This page first made public: Oct 7, 2015

Summary

This is one component of the Source to Sink Mini Lesson Set

In this module, students will be provided with data of monthly mean sea level pressure (MSLP) from Tahiti and Darwin, Australia, from which they will calculate the Southern Oscillation Index (SOI) of ENSO from January 1933 to August 2013 and will compare their calculated SOI with a case study of the Huanghe river, China. Students will be provided with data of Huanghe River discharge and Huanghe basin-wide river discharge from 1950-2013. The anthropogenic effects and ENSO effects on the Huanghe will be examined in this exercise, with discussion of the impact on the river itself, and also the impact ENSO and humans are having on the delta and river mouth of the Huanghe.

The term El Niño-Southern Oscillation (ENSO) refers to a fluctuation as a result of changing sea surface pressures across the equatorial Pacific. ENSO and the quantitative SOI tell us when there is a shift in climate that affects weather phenomenon globally. The end members of ENSO are El Niño and La Niña events. The timing between these events is irregular, yet they typically recur every 3 to 7 years.

Learning Goals

Students will develop an understanding of major climate patterns from taking sea surface pressure measurements and converting them to ENSO SOI values. Students will also see the impact the climate and humans are having on the Huanghe River, China, by looking at basin-wide precipitation and river discharge records. Connections between ENSO and precipitation and river discharge will be made, as will human impacts on the river, allowing for a view of the changes of the Huanghe river itself and the river delta geomorphology.

Context for Use

This module is appropriate for mid- and upper-level undergraduate courses in oceanography, environmental science, sedimentology and stratigraphy, and geography. Students should have a basic understanding of river hydrology and the role of river sediments in constructing the continental margin. The students will need computers connected to the internet, in order to access online databases and visualization freeware such as GeoMapApp , and Google Earth. The sub-modules are suitable for in-class, laboratory, or homework assignments. Combined the entire module is suitable for a multi-day activity.

Description and Teaching Materials

This module consists of:

Part 1: A lecture introducing ENSO and SOI. Brief discussion of the take-home assignment and groups are assembled.

Part 2: The take-home group assignment where the students will take sea surface pressure measurements and convert them into SOI values. They will then make the SOI plot.

ENSO and the Huanghe Take-Home Group Assignment (Microsoft Word 31kB Nov13 13) Darwin & Tahiti MSLP Data (Excel 33kB Nov13 13)

Part 3: The Huanghe river is introduced in class. Students are sitting in the groups that worked on the SOI plot together. They can discuss answers to the in-class worksheet questions in this module.

ENSO and the Huanghe In-Class Group Assignment (Microsoft Word 644kB Dec1 14)

Part 4: Completion of module consists of a class discussion of their answers and any additional discussion of the Huanghe (other figures or conclusions from the Wang et al. (2006) study). doi:10.1016/j.gloplacha.2006.01.005

ENSO and the Huanghe PowerPoint Presentation (PowerPoint 6.9MB Dec1 14) (Portions of this PowerPoint presentation will be used for Part 1, 3 and 4 of this module. This presentation will have to be broken up into the ENSO/SOI introductory lecture for the beginning of the module, followed by the Huanghe introduction, and concluding the module with any slides that will aid with the final class discussion and/or additional information about the Huanghe).

Teaching Notes and Tips

Data Sources for ENSO Index/SOI: Bureau of Meteorology National Climate Centre, Australian Government

SOI overview
Monthly SOI Data
SOI Archives 1876 to present
Darwin, Australia MSLP Data:
Tahiti MSLP Data:

SOI Calculation/Plotting Guidelines:

-These are guidelines that may help make the SOI graph. First, copy the MSLP data from Tahiti or Darwin into excel. If it all pastes into one cell:

· Click on the cell that contains all the data (upper left cell) and highlight the entire column within the data range. Eg. Select cells in the column that you want to contain data.

· Go to the "Data" tab

· Select "Text to Columns"

· Select "Delimited"

· Check "Tab" and "Space"

· Column data format: "General"

· Finish. Data should be separated into individual cells

· Repeat with other MSLP data. Data can be uploaded into same spreadsheet, as long as both datasets are properly labeled. Verify with the website that MSLP data have been properly copied into Excel.

· Data from 1932 and older can be deleted as it is not used in this exercise.

After SOI values are calculated:

SOI Plot:

In a new column, must get all data into two columns. The following steps will get the data into one column for SOI index and a second column for time (Mon-YY):

  • Type: Jan-33
  • Drag little box in bottom right of cell downwards. Should get Feb-33, then Mar-33, etc.
  • Drag little box down until you get to end of dataset (Aug-13)
  • Copy and paste SOI data values to be in all one column, next to the corresponding months. "Paste Special" will need to be used. Paste special "Values" and check "Transpose" the data. Yes, this will take time. Verify that data is being properly copied. There are a lot of opportunities for error here, so be careful and double check values are correctly being copied and pasted. Once SOI vs. time is plotted, axes positions, labels, and minimum and maximums will likely need adjustment.
  • Plot data. Use Chart Type: "Area Blocks" or "Columns with Depth" or another plot type that allows easy visualization of the SOI. Change colors on graph such that +8 values are one color and -8 values are a different color if possible. Use tick marks for the x-axis, and/or vertical gridlines to easily see when the different SOI values occur.

Note: SOI calculations and figure could be a separate take-home group assignment in order to save class time. It will take a significant amount of time to create the SOI figure. ENSO and SOI could be introduced in class, followed by the take-home assignment. Next class the Huanghe can be introduced and then the students could be in groups, discussing answers to the questions in this module. It will be concluded by a class group discussion of the answers and any additional discussion of the Huanghe (other figures or conclusions from the Wang et al. (2006) study.

Options for adding animations to PowerPoint presentation:

Go to: http://www.pmel.noaa.gov/tao/jsdisplay/

Click: Animation-> 3-D TAO Temp, Wind, Current, and 20°C->Animate!

Click: 60 months-> play!

Can see when there was El Niño and La Niña events since 2008!

Also: Section Plots->plot 1: Dynamic Height, plot 2: SST

http://www.pmel.noaa.gov/tao/elnino/nino-home.html#


ENSO Demonstration:

Fill a large rectangular lunch container with water until approximately 1 inch from the top. Add numerous drops of blue food coloring. Mix. This is the deeper ocean of the equatorial Pacific. Slowly add oil (cooking oil is fine) on top of the water. This is the surface waters of the equatorial Pacific that get heated by the sun. Let the two layers become stratified. Label one side of the lunch container "South America" and the other side "Indonesia and Australia". The trade winds across the Pacific blow from South America to Indonesia. Use a hair dyer to illustrate the trade winds. Make sure the hairdryer does not get wet. Use the hairdryer to blow the trade winds across your model equatorial Pacific Ocean and show the students what happens during ENSO. During El Niño the trade winds are relaxed so more stratification across the Pacific occurs and there is less upwelling off the coast of South America. During La Niña the trade winds are stronger causing more upwelling offshore South America and the warmer surface waters are more concentrated towards Indonesia. Discuss the tie of this water movement due to the trade winds to changes in rain patterns during El Niño (more rain in the Pacific Ocean with drought conditions in Australia/Indonesia and eastern Asia gets less rain) and La Niña (overabundance of rain in Indonesia/Australia and dryer conditions in the central Pacific). This demonstration/discussion combined with the PowerPoint presentation should make it clear what happens during El Niño and La Niña.



Assessment

Written worksheets, data plotting and analysis, group discussion, class participation

References and Resources

  • Australian Government Bureau of Meterology
  • Wang, H., Z. Yang, Y. Saito, J.P. Liu, 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.doi:10.1016/j.gloplacha.2006.01.005
  • Wang, H., Z. Yang, Y. Saito, J.P. Liu, X. Sun, Y. Wang, 2007, Stepwise decreases of the Huanghe (Yellow River) sediment load (1950-2005): Impacts of climate change and human activities, Global and Planetary Change, 57, 331-354.doi:10.1016/j.gloplacha.2007.01.003

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