Mars Global Surveyor
Mars Orbiter Camera

Mars Orbiter Camera (MOC) Low Resolution Images
SPO-2 Observations:
Detailed Cloud Patterns in Martian Northern Hemisphere


Mars Global Surveyor Mars Orbiter Camera Release:          MOC2-52a, -52b
Mars Global Surveyor Mars Orbiter Camera Image ID:         581474081.34501
                                                           P345-01 (Red WA);
							   P345-02 (Blue WA)
156 KByte JPG image

(A) Warning: This color composite does not represent the "true" color of Mars. MOC wide angle images 34501 (red-band) and 34502 (blue-band) were combined with a green-band synthesized by averaging the red and blue bands. The images have been projected to account for the geometry of the camera and orbit. North is up, illumination is from the right. Black areas are where the original images were over-exposed (in order to better image the dark areas).

65 KByte JPG image

(B) Same image with geographic features labeled for context. Perepelkin Crater is about 100 kilometers (62 miles) wide and located at 53°N, 65°W. Tempe Terra is a broad flat region criss-crossed with faults and troughs. Kasei Vallis is a large flood channel around 28°N, 65°W.

You may need to adjust the images for the gamma of your monitor to insure proper viewing.

Note: This MOC image is made available in order to share with the public the excitement of new discoveries being made via the Mars Global Surveyor spacecraft. The image may be reproduced only if the image is credited to "Malin Space Science Systems/NASA". Release of this image does not constitute a release of scientific data. The image and its caption should not be referenced in the scientific literature. Full data releases to the scientific community are scheduled by the Mars Global Surveyor Project and NASA Planetary Data System. Typically, data will be released after a 6 month calibration and validation period.

Click Here for more information on MGS data release and archiving plans.


Cold and cloudy mornings; cool, hazy afternoons. High winds aloft and weather fronts moving slowly to the east. It is winter in the Martian northern hemisphere. One of the many reasons to study Mars is that, at times, its weather is very "Earth-like." At this time of the Martian year, clouds are abundant, especially in the morning and especially in the high northern latitudes. Clouds and fogs are also observed in low-lying areas farther to the south, in some lowlands they are as far south as the equator.

The above color composite images, obtained by Mars Global Surveyor's camera on June 4, 1998, illustrate this Martian "weather report." Most of the thick, white clouds seen here occur north of latitude 35°N (roughly equivalent to Albuquerque NM, Memphis TN, and Charlotte NC). Fog (seen as bright orange because it is lighter than the ground but some of the ground is still visible) occupies the lowest portions of the Kasei Valles outflow channel around 30°N and at 25°N.

Several different types of cloud features are seen. The repetitious, wash-board pattern of parallel lines are "gravity" wave clouds. These commonly form, in the lee--downwind side--of topographic features such as mountain ranges (on Earth) or crater rims (on Mars), under very specific atmospheric conditions (low temperatures, high humidity, and high wind speeds). In this area, the wave clouds are lower in the atmosphere than some of the other clouds. These other clouds show attributes reflecting more the regional weather pattern, occasionally showing the characteristic "slash" shape (southwest to northeast) of a weather front. These clouds probably contain mostly crystals of water ice but, depending on the temperature at high altitude (and more likely closer to the pole), some could also contain frozen carbon dioxide ("dry ice").

MOC images 34501 (the red wide angle image) and 34502 (the blue wide angle image) were obtained on Mars Global Surveyor's 345th orbit about the planet. The pictures were taken around 5:34 p.m. PDT on June 4, 1998. Winter in the northern hemisphere began in mid-February, 1998, and continues to mid-July, 1998.

Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

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