Dynamic Oceanic Water-Masses for the World's Oceans Based on Quantitative Ecoregions
William W. Hargrove and Forrest M. Hoffman
William W. Hargrove and Forrest M. Hoffman
Multivariate clustering based on high-resolution maps of elevation, temperature, precipitation, soil characteristics, and solar inputs has been used at several specified levels of division to produce a series of repeatable, statistically-derived ecoregionalizations of the conterminous United States based on 25 environmental variables. The coarser divisions reflect intuitively-understood regional environmental differences, whereas the finer divisions highlight local condition gradients, ecotones, and clines. Machine-generated ecoregions can be produced based on any user-selected variables, allowing customized regions to be generated for any specific problem.
When ecoregions are delineated using quantitative methods rather than human expertise, the quantitative treatment can be applied to many complex and dynamic multivariate phenomena outside the traditional realms of ecoregions. One such dynamic multivariate environment is the ocean.
We divided the world's oceans into unique water masses dynamically through time in terms of five water characteristics: temperature, salinity, dissolved oxygen, phosphate, and nitrate. All data are at 1 degree resolution, monthly through time, and at each of 14 irregular standard depths. The standard depths are 0, 10, 20, 30, 50, 75, 100, 125, 150, 200, 250, 300, 400 and 500 meters. Each of the unique water masses are colored randomly, but wherever or whenever the same color is seen, the same water mass is identified.
Data are from the NOAA's National Oceanographic Data Center (NODC) World Ocean Database 2001 (WOA01). The five characteristics listed above and thought to be biologically relevant were selected from the database.
Two levels of division have been accomplished: the 500 most different water-masses, and the 1000 most different water-masses.
We have produced two different types of animations to communicate the dynamic water masses which were delineated. Under MS Windows, these standard MPEG-1 format animations do not using the Windows Media Player, but work fine inside IE and using the QuickTime player. All *nix players work fine.
In the first type of animation (only for the 500 division result), we "travel" down and then back up through all of the depth layers once for each month in the synoptic year. After each "bounce" through all of the depths, we move to maps for the next month. At each month change, a global map showing black land continents and white oceans is shown as a recognizable separator.
The first animation shows a "plunge" down and then back up through the 500 common water masses for each month in turn throughout a synoptic year.
In the second type of animation, results for each of the two levels of division (500 and 1000) are presented as a set of four animations. Up to four discrete depths are shown in each animation. Each animation contains 12 monthly frames showing the movement of identified water masses through time. Depth increases clockwise from the upper left in each animation frame.
| 0m | 10m |
| 30m | 20m |
The surface.500.mpg animation shows the 500 common water-masses at depths of 0, 10, 20, and 30 meters, clockwise from upper left, through a 12 month sequence.
| 50m | 75m |
| 125m | 100m |
The upper.500.mpg animation shows the 500 common water-masses at depths of 50, 75, 100, and 125 meters, clockwise from upper left, through a 12 month sequence.
| 150m | 200m |
| 300m | 250m |
The middle.500.mpg animation shows the 500 common water-masses at depths of 150, 200, 250, and 300 meters, clockwise from upper left, through a 12 month sequence.
| 400m | 500m |
| X | X |
The deep.500.mpg animation shows the 500 common water-masses at depths of 400 and 500 meters, clockwise from upper left, through a 12 month sequence.
Click here for the legend and characteristics table for the 500 most different oceanic water-masses animations.
| 0m | 10m |
| 30m | 20m |
The surface.1000.mpg animation shows the 1000 common water-masses at depths of 0, 10, 20, and 30 meters, clockwise from upper left, through a 12 month sequence.
| 50m | 75m |
| 125m | 100m |
The upper.1000.mpg animation shows the 1000 common water-masses at depths of 50, 75, 100, and 125 meters, clockwise from upper left, through a 12 month sequence.
| 150m | 200m |
| 300m | 250m |
The middle.1000.mpg animation shows the 1000 common water-masses at depths of 150, 200, 250, and 300 meters, clockwise from upper left, through a 12 month sequence.
| 400m | 500m |
| X | X |
The deep.1000.mpg animation shows the 1000 common water-masses at depths of 400 and 500 meters, clockwise from upper left, through a 12 month sequence.
All unique water masses were delimited using Multivariate Spatio-Temporal Clustering (MSTC) using a parallel supercomputer. MSTC has also been used to quantitatively determine ecoregions on land through time, and to track the formation and movement of unique air masses within the atmosphere.
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