MATLAB Examples

isgrounded documentation

The isgrounded function returns logical true wherever there is grounded Antarctic ice according to MEaSURES Antarctic Boundaries for IPY 2007-2009 from Satellite Radar, Version 2.

The dataset is described on the NSIDC site here: http://nsidc.org/data/NSIDC-0709

Syntax

```tf = isgrounded(lati,loni)
tf = isgrounded(xi,yi)```

Description

tf = isgrounded(lati,loni) returns true for all geo locations (lati,loni) identified as grounded ice in the Mask_Antactica_v2.tif (sic) dataset.

tf = isgrounded(xi,yi) returns true for all locations identified as grounded ice in Mask_Antactica_v2.tif (sic), where input coordinates are automatically determined to be polar stereographic (true lat 71 S) meters if their values exceed the normal lat,lon range.

This example uses a Gravity Plugin for AMT to load some example data, but I'll show you how you can follow along without loading that dataset. Whether you have the gravity plugin or not, begin by creating a 300 km wide grid centered on PIG, at 0.25 km resolution:

```[lat,lon] = psgrid('pine island glacier',300,0.25); ```

If you have the gravity plugin, interpolate gravity values to the grid like this:

```FA = gravity_interp(lat,lon,'free air'); ```

If you don't have the gravity plugin you can simply use random data like this:

`FA = rand(1201);`

Use isgrounded to find out which parts of the dataset are over grounded ice:

```grounded = isgrounded(lat,lon); ```

Mask-out all non-grounded ice (use the tilde for NOT) by setting it to NaN:

```FA(~grounded) = NaN; ```

Plot the grounded gravity data:

```pcolorps(lat,lon,FA) axis tight ```

For context, overlay a red grounding line and a black coastline:

```antbounds('gl','r') antbounds('coast','k') ```

Citing this dataset

If you use this dataset, please cite the following:

• The dataset: Mouginot, J., B. Scheuchl, and E. Rignot. 2017. MEaSUREs Antarctic Boundaries for IPY 2007-2009 from Satellite Radar, Version 2. [Indicate subset used]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. http://dx.doi.org/10.5067/AXE4121732AD.

Author Info

This function and supporting documentation were written by Chad A. Greene of the University of Texas Institute for Geophysics (UTIG), November 2016. Updated May 2017.