Texas Clipper Trip Report 5/17

[LVX]

Check out the loop current flow in the Gulf and tell me how water from the Mississippi can make it's way to Port Isabel when the flow south of Aransas is northbound.

The Loop Current

sorry for the armchair analysis but your own pic showing the loop current has arrows moving towards the west which is south Texas.

Generally, much of the river water discharged into the northern Gulf of Mexico by the Mississippi and Atchafalaya Rivers moves westward along the Louisiana and Texas coasts, driven primarily by the prevailing easterly winds. Freshwater from these rivers has been observed as far as Port Aransas, Tex., 800 km from the Mississippi River delta.

And no, this is not talking about subsurface currents.

Layne

 

[ReefHound]

"During the 1993 summer, not only was river discharge anomalously high but the direction of flow of river water in the northern Gulf of Mexico was also unusual. Generally, much of the river water discharged into the northern Gulf of Mexico by the Mississippi and Atchafalaya Rivers moves westward along the Louisiana and Texas coasts, driven primarily by the prevailing easterly winds. Freshwater from these rivers has been observed as far as Port Aransas, Tex., 800 km from the Mississippi River delta." (emphasis added)

You added the emphasis on the wrong part, it should have been "Freshwater from these rivers has been observed as far as Port Aransas, Tex., 800 km from the Mississippi River delta." Note that this upper end range is still some 300km north of the Clipper.

 

[ReefHound]

sorry for the armchair analysis but your own pic showing the loop current has arrows moving towards the west which is south Texas.

Generally, much of the river water discharged into the northern Gulf of Mexico by the Mississippi and Atchafalaya Rivers moves westward along the Louisiana and Texas coasts, driven primarily by the prevailing easterly winds. Freshwater from these rivers has been observed as far as Port Aransas, Tex., 800 km from the Mississippi River delta.

And if you would bother to read that chart you would see the westward flow ends well before "south Texas". The range "as far as" Aransas is still 300km north.

You can use the chart as valid data or you can choose to disregard it, but you can't pick some of the arrows (the ones going west from Miss. to Aransas) you like and ignore the other arrows (the ones going due north from Campeche to Aransas).

 

[LVX]

stay current, stay; bad, current bad current...

 

[IslandFrog]

Either way, it could get to be a fun dive for whoever is running the camera!

The wetsuits may be a bit pricey, but maybe we can take a DIMWIT flag and fly it from the down line. That would make a great shot.

I need to check with Tim and see what his bookings look like. I'm thinking maybe some time in August.

 

[Guba]

Well, I AM a scientist, and I'm also a volunteer lecturer for the Flower Garden Banks NMS, and I HAVE had training in the currents that flow through the Gulf of Mexico, so I'll take a shot at it.

The GOM eddy (loop) is a huge garden hose that is pouring water into a closed vessel (the GOM itself). As it "dead-ends" against the continent, it breaks into dozens and dozens of smaller eddies. Some of these spiral clockwise, producing coastal currents flowing north. Occassionally, some flow counter clockwise, carrying currents that have a more southerly route. Couple that with huge outflow from a flooded continent trying to drain itself, and things can get really mixed up. This can, indeed, produce "squirts" of current that carry silt-laden water far down the western curve of the Gulf, all the way to Port Aransas and even farther. We've even had some Mississippi silt deposited on the FG itself, though that is a very rare occurrence. However, there is growing concern that the hypoxic "dead zone" around the Mississippi delta fan could ultimately reach the FGBNMS. That could only happen if the currents were to swirl far south of their normal path, but it does happen.
If you need more information, you might contact the Gulf of Mexico Foundation or the FGBNMS itself. They're always happy to share their data.

 

[IslandFrog]

The main thing is that we got in some really good dives on a relatively new Texas dive site under unusual and challenging conditions... and we all got showed up by the Hawksbill. Sorry Guba, not even my SAC was good enough to keep up with him! LOL

 

[ReefHound]

Well, I AM a scientist, and I'm also a volunteer lecturer for the Flower Garden Banks NMS, and I HAVE had training in the currents that flow through the Gulf of Mexico, so I'll take a shot at it.

Then you should have no trouble pointing me to hard data, right?

The GOM eddy (loop) is a huge garden hose that is pouring water into a closed vessel (the GOM itself). As it "dead-ends" against the continent, it breaks into dozens and dozens of smaller eddies. Some of these spiral clockwise, producing coastal currents flowing north. Occassionally, some flow counter clockwise, carrying currents that have a more southerly route. Couple that with huge outflow from a flooded continent trying to drain itself, and things can get really mixed up. This can, indeed, produce "squirts" of current that carry silt-laden water far down the western curve of the Gulf, all the way to Port Aransas and even farther.

You're winging it, aren't you?

This is certainly plausible but it sounds to me like a wild eyed guess based on possibilities, not confirmed data. The continent is always draining into the gulf, the ole Miss may be a little high but I must have missed all the floods in the news.

OK, the point is I think the "Mississippi outflow" is a convenient scapegoat given out on a routine basis to explain away poor viz on any given day. If they said "oh, sorry for the poor viz, it always sucks like this" then it would be bad for business.

 

[texdiveguy]

OK, the point is I think the "Mississippi outflow" is a convenient scapegoat given out on a routine basis to explain away poor viz on any given day. If they said "oh, sorry for the poor viz, it always sucks like this" then it would be bad for business.

So lets hear your educated explanation to the brown river muck at various levels of the southern gulf coast water column.....the explanations expressed here all sound solid and since I have persl. witnessed it, I find these are solid viable answers that match what has been explained to me for years now....but we have not heard your twist on what causes the muck and were does it originate..?

 

[Mack Diver]

So lets hear your educated explanation to the brown river muck at various levels of the southern gulf coast water column.....the explanations expressed here all sound solid and since I have persl. witnessed it, I find these are solid viable answers that match what has been explained to me for years now....but we have not heard your twist on what causes the muck and were does it originate..?

Personally, I don't give a c**p about why the conditions were there. All I know is those were the conditions and those of us that braved them enjoyed a heck of a trip. Can you tell I'm not much of a science person