Subject: Marine Geospatial Ecology Tools (MGET) help
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From: | Jason Roberts <> |
---|---|
To: | Marie Winger <>, |
Subject: | Re: [mget-help] How to detect eddy cores and edges |
Date: | Wed, 01 Feb 2012 14:23:25 -0600 |
Hi Marie,
Thank you for the kind words. We hope MGET proves useful for projects.
Currently, the Okubo-Weiss tool only outputs the cells representing the eddy
cores. If a raster cell has a value, it is an eddy core. If not, it is either
an eddy ring or background. The values of the core cells are identification
numbers, arbitrarily assigned by the tool. As you discovered, you can
optionally obtain polarity and age rasters as well.
Is is possible to obtain the Okubo-Weiss parameter value itself (W), but only
if you write some code. We have had some but limited success using it to
identify the ring (i.e. the strain-dominated part of the eddy). Often, the
ring is only one cell wide and frequently does not surround the core fully
and contiguously. The resolution of the Aviso data does not appear to be high
enough to fully and reliably resolve rings. Nevertheless, we have a masters
student who is about to submit a paper to use this approach.
If you would like us to modify the tool to output the Okubo-Weiss parameter
value as a raster so you can try this approach, it should not be difficult
for me to do so. I can probably do that next week or the week after (I am
traveling for most of this week and next.) Let me know...
Best,
Jason
Thank you for the kind words. We hope MGET proves useful for projects.
Currently, the Okubo-Weiss tool only outputs the cells representing the eddy
cores. If a raster cell has a value, it is an eddy core. If not, it is either
an eddy ring or background. The values of the core cells are identification
numbers, arbitrarily assigned by the tool. As you discovered, you can
optionally obtain polarity and age rasters as well.
Is is possible to obtain the Okubo-Weiss parameter value itself (W), but only
if you write some code. We have had some but limited success using it to
identify the ring (i.e. the strain-dominated part of the eddy). Often, the
ring is only one cell wide and frequently does not surround the core fully
and contiguously. The resolution of the Aviso data does not appear to be high
enough to fully and reliably resolve rings. Nevertheless, we have a masters
student who is about to submit a paper to use this approach.
If you would like us to modify the tool to output the Okubo-Weiss parameter
value as a raster so you can try this approach, it should not be difficult
for me to do so. I can probably do that next week or the week after (I am
traveling for most of this week and next.) Let me know...
Best,
Jason
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