Studying climate dynamics/ physical oceanography

Required student background for studying climate dynamics/ physical oceanography and the study program.

Research activities in climate dynamics span a wide range of topics and methods of work:

From basin length scale (1000km) & a few years time scale (El Niño) to global, 100,000 years scales (glacial-interglacial oscillations)

From low-order chaos and nonlinear dynamics in the climate system to fully turbulent oceanic and atmospheric flows.

From pencil and paper to super computers and real data from research ships and satellites.

From the practical (develop methodologies and models for predicting greenhouse warming; El Niño) to the more curiosity driven (is global climate stable? why?)

One of the important distinguishing elements of this research area is that there are still many very fundamental zeroth order problems that are unsolved in climate research.  The scientists working in this area are very far from having to deal only with polishing the final details.  Below are some examples of such open research questions that we investigate.

1) Why is El Niño irregular? (low order chaos or high dimensional atmospheric noise?)

A time series of the sea-surface temperature in the eastern Pacific Ocean showing El Niño events as peaks that occur irregularly and are therefore difficult to predict.
 
 

2) Why is El Niño's peak time always near the end of the calendar year?

Many El-Niño events (sea-surface temperature in the eastern Pacific Ocean) plotted as function of month (January to December over two years).  nearly all events peak at the end of the calendar year, around December-January.

3) Why do glacial-interglacial oscillations occur? Why do they have a 100kyr time scale?

A time series of climate variables measured from an ice core (a 3,300 meter deep cylinder of ice drilled in Antarctica and representing snow accumulated there over the past 400,000 years).  Note the plotted 100,000 year oscillations in the global ice volume over the earth.

4) Why did the atmospheric concentration of CO2 change so dramatically during these glacial-interglacial cycles?

Another ice-core record, with the atmospheric concentration of CO2 plotted on top.  Note that CO2 concentration has varied between 180 and 280 during the glacial-interglacial oscillations.  Present concentration due to man's activities is 360 and is expected to double within the next few decades.

5) Why has climate during the past 10,000 years been so stable (weak variability), while before that it was very unstable (strong variability).

Another record of a climate variable showing that the past 10,000 years (upper most part of the figure) have been remarkably stable and with small variability, while before that, climate was far more unstable with climate fluctuations being significantly stronger.

Examples of our more applied work subjects

Earth's climate is, of course not only a source of interesting and challenging research questions as in the above examples, but also affects our life on a daily basis, through the effects of natural climate variability like El Niño as well as through our influence on climate through greenhouse warming.  Some of our activities are addressing the more applied side of climate dynamics, developing tools to help predict climate and its implications.  A couple of such examples of our work are

 
Combine 3d models of the ocean and atmosphere, with 4d data from ships, satellites, deep-sea moorings, etc in order to produce a better prediction of El Niño. Use variational data assimilation based on optimal control/ adjoint models.

 
 

Required student background and typical study program

Students with an undergraduate or M.A. degree in physics or geophysics are well prepared to study climate dynamics and physical oceanography.  The program of study includes basic courses in the fluid dynamics of the oceans and the atmosphere (geophysical fluid dynamics), as well as background courses in physics and applied mathematics.  Some typical test books in geophysical fluid dynamics are:

Pedlosky - Geophysical Fluid Dynamics
Pedlosky - Ocean circulation theory
Gill - Atmosphere-ocean dynamics
Holton - An Introduction to Dynamic Meteorology
Lindzen - Dynamics in Atmospheric Physics
 
  

The "footprint" of a whale diving down from the surface (c.p.)

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