MATLAB Examples

icesat

icesat plots the grounding zone inferred by ICESat. Data details can be found here. This command has a rather general name for a rather specific function because it may be updated at a future time to include plotting features more types of data related to the ICESat instrument. Run icesat_grounding_zone_install.m before using the icesat function.

Contents

Syntax

icesat('mapvar')
icesat(...,'optionName',optionValue)
icesat(...,'labels','on')
h = icesat(...)

Description

icesat('mapvar') plots the mapvar which can be 'f' for the landward limit of flexure, 'h' for the point where ice becomes hydrostatically balanced, or 'i' for the break-in-slope associated with flexure.

icesat(...,'optionName',optionValue) formats the plotted data.

|icesat(...,'labels','on') labels the track numbers used to calculate the the grounding zone feature.

h = icesat(...) returns a handle h for plotted objects.

Requirements

This function requires the Matlab Mapping Toolbox and Chad Greene's Antarctic Mapping Tools package.

Example: Compare points of the grounding zone

First we'll plot the landward limit of ice flexure. By default, data points are plotted as black dots.

icesat('f')

Now let's add a plot the hydrostatic line in blue and the break-in-slope in red.

icesat('h','color','blue');
h = icesat('i','color','magenta');

Oops! We accidentally plotted the break-in-slope in magenta. Let's change it to red, as we intended.

set(h,'color','red');

Now let's take a closer look. If you have the Bedmap2 Toolbox for Matlab you can use the mapzoom command shown below. Otherwise you'll have to zoom manually.

mapzoom('siple dome','mapwidth',250,'inset','northwest')

Of course, a bunch of little dots are not terribly interesting when they are out of context and too small to see. Using some commands from the Bedmap2 Toolbox for Matlab we can which ICESat tracks were used to obtain these data? Let's replot on top of an ice thickness map to get a better idea of what's going on here. Start by creating a new figure of ice thickness. The 'latlim' and 'lonlim' values are declared to reduce the amount of unnecessary data plotting.

figure
bedmap2('thickness','latlim',[-85 -75],'lonlim',[-175 -140],'resolution','1 km',...
    'colormap','gray','clim',[300 1000])

Now we can plot the grounding zone structure and zoom in on something interesting.

icesat('i','color','red','markersize',8)
icesat('f','color','green','markersize',8)
icesat('h','color','blue','markersize',8,'labels','on')
mapzoom(-81,-155,'mapwidth',300,'inset','southeast')

Example: Mimic Brunt et al.'s Foundation Ice Stream grounding zone structure

The following example was inspired by Figure 5 of Brunt et al.'s (2011): Here we overlay an asaid grounding line on a modismoa image. Matlab's list of color names is somewhat limited, so we'll use rgb to get the RGB values of orange and medium blue:

close all % closes previous figures
modismoa('foundation ice stream',250,'inset','northwest')
asaid('gl','color',rgb('medium blue'),'linewidth',2)
icesat('f','color','yellow','markersize',12)
icesat('h','color','cyan','markersize',12)
icesat('i','color',rgb('orange'),'markersize',12)
scalebar('length',50,'location','southwest','color','w')

Author Info

This function was written in April 2014 by Chad A. Greene of the University of Texas at Austin Institute for Geophysics. Feel free to email me anytime with questions or comments.