Longitudinally Oriented Cloud Longitudinally Oriented Cloud Systems Associated With The Systems Associated With The Gulf Stream Off The Florida Gulf Stream Off The Florida

East CoastEast Coast

Wanda ReevesWanda ReevesDepartment of Marine Environmental Department of Marine Environmental

SystemsSystemsFlorida Institute of TechnologyFlorida Institute of Technology

Melbourne, Fl 32901Melbourne, Fl 32901

Weather.msfc.nasa.gov

Theories for Longitudinally Theories for Longitudinally Oriented Cloud Systems Oriented Cloud Systems • Two theories have been proposed to Two theories have been proposed to

explain circulations that generate explain circulations that generate these cloud systems in the Gulf these cloud systems in the Gulf Stream region.Stream region.

-Solenoid Theory-Solenoid Theory -Marine Atmospheric Boundary Layer -Marine Atmospheric Boundary Layer (MABL) Theory (MABL) Theory

Solenoid TheorySolenoid Theory• A theory in which winds are driven by A theory in which winds are driven by

the thermal/density differences the thermal/density differences between air masses. The cold, dense between air masses. The cold, dense air sinks and the warm, less dense air sinks and the warm, less dense air rises creating a circulation that air rises creating a circulation that forms solenoids. forms solenoids.

Cool Shelf Water

Solenoid Theory Solenoid Theory

High Low High

More Dense AirLess Dense Air More Dense Air

Warm Gulf Stream WaterCool Atlantic Water

Solenoid TheorySolenoid Theory

A B

When the wind is from the east, convection is expected to be located at the “frontal zone” labeled A and when the wind is from the west, convection is expected to be located along a “frontal zone” at point B.

More Dense AirLess Dense AirMore Dense Air

Cool Shelf WaterGulf Stream WaterCool Atlantic Water

N

S

EW

Marine Atmospheric Boundary Layer Marine Atmospheric Boundary Layer TheoryTheory A theory that is based upon Sea A theory that is based upon Sea

Surface Temperature Gradients and Surface Temperature Gradients and that winds are proportional to that winds are proportional to temperatures near the surface. temperatures near the surface.

Illustration, from “Satellite Measurements Reveal Illustration, from “Satellite Measurements Reveal Persistent Small-Scale Features in Ocean Winds” Persistent Small-Scale Features in Ocean Winds” article, of how the wind varies in the Marine article, of how the wind varies in the Marine Atmospheric Boundary LayerAtmospheric Boundary Layer

Warm and Destabilized

Cool and Stabilized

0 5 10

100

200

Wind Speed (m/s)

Heig

ht (m

)

300

www.sciencemag.orgAuthors: Dudley B. Chelton, Michael G. Schlax, Michael H. Freilich, Ralph F. Milliff

Schematic diagram, from research article “Satellite Schematic diagram, from research article “Satellite Measurements Reveal Persistent Small-Scale Measurements Reveal Persistent Small-Scale Features in Ocean Winds”, of divergence and curl Features in Ocean Winds”, of divergence and curl of the wind stress (tao) resultiing from spatial of the wind stress (tao) resultiing from spatial variations of the sst effects on the surface winds variations of the sst effects on the surface winds

Cool

Warm

DivergencePositive Vorticity

Divergence/Convergenceneeds winds to be parallelto the temperature gradient

Marine Atmospheric Boundary Marine Atmospheric Boundary Layer Layer

ConvergenceDivergence

Easterly Flow

Warm Gulf StreamCool Atlantic WaterCool Shelf Water

Marine Atmospheric Boundary Marine Atmospheric Boundary LayerLayer

Westerly Flow

Cool Shelf Water Warm Gulf Stream Cool Atlantic Water

Divergence

Convection along the west edge of Gulf Convection along the west edge of Gulf Stream on April 21,2005 (1556 UT)Stream on April 21,2005 (1556 UT)

NOAA-17 AVHRR Water Surface Temperature Image Courtesy of Ocean Remote Sensing Group, Johns Hopkins University Applied Physics Laboratory

Convection along the west edge of the Convection along the west edge of the Gulf Stream on June 8, 2005Gulf Stream on June 8, 2005

Johns Hopkins University Applied Physics Laboratory

Convection along the east side and middle of the Convection along the east side and middle of the Gulf Stream on May 15, 2005 (2015 UT)Gulf Stream on May 15, 2005 (2015 UT)

Johns Hopkins University Applied Physics Laboratory

Convection in the middle of the Gulf Stream Convection in the middle of the Gulf Stream on May 12, 2005 (1135 UT)on May 12, 2005 (1135 UT)

Johns Hopkins University Applied Physics Laboratory

An example of convection that meanders along and An example of convection that meanders along and through the Gulf Stream on May 2, 2005 (2330 UT)through the Gulf Stream on May 2, 2005 (2330 UT)

Johns Hopkins University Applied Physics Laboratory

925 mb upper atmosphere chart for June 8, 925 mb upper atmosphere chart for June 8, 2005.2005.

Spc.noaa.gov/

An example of Ship and Buoy Data Observations An example of Ship and Buoy Data Observations used in the convective clouds determination used in the convective clouds determination process.process.

This is a GOES West Satellite Composite Infrared This is a GOES West Satellite Composite Infrared Image for June 8, 2005. Image for June 8, 2005.

SFSU.edu

GOES12 (4 km) through Garp

This scatterometer picture for June 8, 2005 shows This scatterometer picture for June 8, 2005 shows convergence where the winds shift from a convergence where the winds shift from a Southeast direction at 10 knots to East at 5 knots. Southeast direction at 10 knots to East at 5 knots. This gives an indication of convergence of the wind.This gives an indication of convergence of the wind.

This is the same Scatterometer Image but This is the same Scatterometer Image but with Convergence and Divergence with Convergence and Divergence calculated.calculated.

West Side of Gulf Stream

April 5 April 21

N NE E SE S SW W NW June 8 June 13 April

22 April 28

June 16

Middle of Gulf StreamN NE E SE S SW W NW

April 22 May 7

May 17

June 8

May 15

June 26

May 12 April 5

April 28

East Side of Gulf StreamN NE E SE S SW W NW

April 21 June 26 May 15

Questions?Questions?

Ryan Brown