[CIG-LONG] GALE: Time dependent loading of an unstable layer

[Karen Paczkowski]

Hi,

I am a graduate student at Yale University.  I am interested in using  
GALE for a number of my research projects, but I have a few questions.

The first project I am working on involves looking at climate-tectonic  
interactions.  I would like to set up a system of two layers  
(lithosphere and mantle).  Where the top layer is more dense and more  
viscous than the bottom layer.  I would then like to apply a vertical  
load that oscillates in time to the top of the entire box (like  
b*cos(x)*cos(w*t) where b is the amplitude of the load and w is the  
loading frequency and x is the position along the box)

Ultimately, I would like to track the growth and development of a  
Rayleigh-Taylor instability due to the applied cyclical vertical  
loading.

I have never used a large code like GALE before and am a little lost  
on what it is capable of and how to implement what i'd like.  I have  
read through the users manual and gone through all of the tutorials,  
but still have many questions.  The main ones are:

1)  How can I create a time dependent forcing function?  Ideally I  
would like a time dependent normal force on the top of the box that is  
a combination of the relaxation of the topography (like in the  
sinusoidal.xml) and the oscillating applied vertical loading.

2)  Can I track the rate a certain interface/isotherm/etc moves?  For  
example, in the cookbook there is a topography relaxation example.  I  
can get the correct images for the strain rate invariant and velocity  
field, but I'm not sure how to determine the relaxation rate of the  
top interface.  Is there a simple way to do this?  I would like to  
track the growth rate of the Rayleigh-Taylor instability.  Will this  
be possible?

To determine if I can use GALE for this project these two questions  
are the most important.

Any help and advice you have will be greatly appreciated.

Thanks!
Karen Paczkowski
PhD Candidate
Yale University