Photo STS 51a-032-058

ITEM	PARAMETER
Mission	STS 51a-032-057
Vehicle	.
Launch	November 8, 1984
Landing	November 16, 1984
Orbital altitude, nm	163
Orbital inclination, deg	28.0^o
Camera	HB: Hasselblad
Camera Tilt	17^o
Camera Focal Length	250 mm
Camera look Direction	East
Image	.
Film	6017: Kodak Ektachrome 64, 220 Roll Format
Film Exposure	Normal
Percentage of Cloud Cover	0
Sun Azimuth^*	157^o
Sun Elevation Angle^**	54^o
Orbital Number	20
Nadir, deg/min	15.6^oN, 94.8^oW
Center of scene, deg/min	15.5^oN, 94.0^oW
Imaged time	November 9, 1984, 17:10:22(GMT)
^Sun Azimuth: clockwise angle in degrees from north to the sun measured at the nadir point. ^*Sun Elevation Angle: angle in degrees between the horizon and the sun, measured at the nadir point.

ITEM	PARAMETER
Mission	STS 51a-032-058
Vehicle	.
Launch	November 8, 1984
Landing	November 16, 1984
Orbital altitude, nm	163
Orbital inclination, deg	28.0^o
Camera	HB: Hasselblad
Camera Tilt	13^o
Camera Focal Length	250 mm
Camera look Direction	East
Image	.
Film	6017: Kodak Ektachrome 64, 220 Roll Format
Film Exposure	Normal
Percentage of Cloud Cover	0
Sun Azimuth^*	157^o
Sun Elevation Angle^**	55^o
Orbital Number	20
Nadir, deg/min	15.4^oN, 94.6^oW
Center of scene, deg/min	15.5^oN, 94.0^oW
Imaged time	November 9, 1984, 17:10:26(GMT)
^Sun Azimuth: clockwise angle in degrees from north to the sun measured at the nadir point. ^*Sun Elevation Angle: angle in degrees between the horizon and the sun, measured at the nadir point.

Background The Gulf of Tehuantepec is located to the south of Mexico. The continental shelf in the Gulf of Tehuantepec is very narrow. Within 50 km or so, the water depth goes down to 4000 meter, which is the Middle America Trench. The Guatemala Sea Basin, drops deeper than 4000 meter, is located to the south of the Gulf of Tehuantepec. Many internal wave packets have been detected in this area, but these internal waves are quite small. When tide currents flow over the shelf break in the stratified fluid, internal waves are produced. The shelf break is located near 94W longitude.

Space Shuttle Photography and Interpretation Space Shuttle photographs sts51a-032-057 and sts51a-032-058 each recorded the same internal wave packets in the Gulf of Tehuantepec, along to the south of Mexico. The coverage of each of these images on the sea surface is 85Km * 85km. These photographs were taken at 11:10(local time), November 9, 1984.

These two photographs have imaged the same clouds, and the time gap between them is 4 seconds, so we can combine them easily. We can see that the coastline of Mexico at the bottom of the sts51a-032-058 photograph. There are two internal wave packets: one of them ( A ) is propagating toward the land with its wave crestline parallel to the shoreline, the other wave packet has a 45^o angle with respect to the coastline.

Photograph STS 51a-032-058