Wind and density driven flow along the Texas-Louisiana continental shelf

Rob Hetland

Zhaoru ZhangMartino Marta-AlmeidaXiaoqian Zhang

The Gulf of Mexico has a number of environmental problems:

Karenia brevisPhoto credit: Florida Fish and Photo credit: Florida Fish and Wildlife Conservation CommissionWildlife Conservation Commission

NASA MODISMay 24, 2010

Harmfulalgal blooms

Oil spills

Bottom hypoxia

LUMCON - July 24-27, 2012

And the listgoes on....

Series of Models:

Wind-driven surface current predictions

for entire gulf – focused on TX shelf

Louisiana shelf wind/buoyancy driven flow

TX/LA shelf wind/buoyancy driven flow

NEXT TALK

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Animation courtesy Chris Barker (NOAA R&R)Surface currents provided by Rob Hetland and Steve Baum, TAMUFunding by the Texas General

Land Office TABS program

B

D

F

J

K

N

R

V

W

~3 hr lag

~12 hr lag

Four examples of non-summer convergent events

Wind Currents

No river case

Wind

Obs.

Model

20092006 10 year mean

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Climatological winds over the Texas-Louisiana shelf

Non-summer mean

Summer mean

Cho et al. (JGR, 1998)

Seasonal surface currents from LATEX moorings

JFM mean density cross-section

JFM mean along-shore currents

Thermal wind balance currents

u|z=h=0

Along-shore currents are nearly in thermal-wind balance

Meade et al. (1995)USGS Circular 1133

Low flow year

Medium flow year

High flow year

Every third grid point shown

HYCOM IASNFS (subset) NGOM

Parent models Nested modelsCLMDataset

Model salinity skill

Red = good (within 10% of max skill)

where

Perturbed simulations(±5% wind and rivers)

Noise at a point on the shelf

Domain average noise

Conclusions:

Nesting improves model skill, but it does not appear to matter which model is used*.

Although there is significant unpredictable, small-scale eddies at the submesoscale, the large scale plume structure is reproducible in a model without data assimilation.

*For salinity, anyways...