SAN FRANCISCO STATE UNIVERSITY
DEPARTMENT OF GEOSCIENCES
NAME _______________________
Spring 2013
METR 415/715: MONTEVERDI QUIZ 1
Open Book and Open Notes
200 points, 45 minutes
1. Compute the altitude of a geostationary orbit for Mars. (radius = 3,397 km;
mass=6.4219 X 1023 kg; orbital period=~24 h). (50 points)
Show all work. Label all equations sequentially with numbers.
Problem 1:
Equations Needed
2
m
V
Fc = sat R
Fg = Gmsat mm
V = wR
(1)
R2
(2)
(3)
Relations or Constants Needed
R = Rm + h
w = 7.292X10-5 s-1
Rm = 3.397X10 6 m
M m = 6.4219X10 23 kg
ö÷
-11 æ m 2
G = 6.67X10 Nç
è kgø
(4)
Solution
For a geosynchronous orbit,
Fc = Fg
(5)
Insert (1), (2), (3) and (4 b, d and e) into (5) and solve for R
R3=8.056 X 1021 m3
(6)
R=2.005 X 107 m
(7)
Substitute (4a and b) into (7) and solve for h
h=1.66 X 107 m = 16,600 km
2
(8)
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2. Examine the satellite images below (55 points):
Satellite Image A
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Satellite Image B
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A. State whether the satellite images were from the imagers of a geostationary satellite
or a polar orbiter, and why. (10 points)
The images are from the GOES-12 satellite. The images are labeled as such at the
bottom of the image. Also, the imagery has a much wider east-west extent than
imagery from the POES.
B. State the size of a cloud element for the two images, and why. (15 points)
The images have a resolution of 4 km. The images are so labeled on the bottom.
Since a cloud element is the smallest resolvable feature on the imagery, a cloud
element would have a diamter of 4 km on these images.
C. What is the cloud top temperature at the three way border of Louisiana, Arkansas and
Mississippi? (10 points)
The color temperature on the infrared image in the area of the
Louisiana/Mississippi border is on the boundary of dark greengrey. This
corresponds to a temperature between -60 C to -70C.
D. Although the Satellite Image B uses a color enhancement curve, that enhancement
most closely resembles which of the following grey scale enhancement curves: (a)
Standard; (b) ZA; (c) MB. (5 points) ) MB.
E. The color enhancement probably is designed to highlight what features of
meteorological significance. Explain. (10 points)
The color enhancement appears to highlight the coldest tops of cumulonimbus
clouds.
F. Which Channel was used to obtain the data for Image B? (5 points)
The data comes from Channel 4.
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3. Examine the enhancement curve given below. (25 points)
A. What is the designation (name) of this enhancement curve? (10 points)
This is the MB enhancement curve, designed to highlight convective storms.
B. The enhancement curve shown above appears to highlight color changes between
-40C and -80C. What is the purpose for highlighting these temperatures? (15 points)
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This enhancement curve designed to highlight convective storms and the clouds at
the upper levels of hurricanes.
4. The following image is a GOES-15 Visible 4 km image processed by the US Navy.
(28 points)
Locate the following by putting the appropriate letter right on the image: (a) Cloud line;
(b) Cloud band; (c) Cloud streets; (d) cumulonimbus.
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5. Examine the Sea Surface Temperature field observed by the Aqua on 3/25/11. (20
points)
(a) Which instrument on the Aqua and Terra platforms senses the data used to create this
plot? (10 points) The instrument is the Moderate Resolution Imaging
Spectroradiometer (MODIS)>
(b) The orange pattern in the eastern portion of the Gulf of Mexico is associated with a
prominent oceanographic current feature. What is the name of that feature? (10 points)
_____ This feature is known as the Loop Current.
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6. Examine the DMSP image below: (22 points)
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A. State how you would know that this image was produced from data sensed by a polar
orbiting satellite, even without legend information on the image. (2 points)
The image shows part of the polar regions.
B. The DMSP satellite is in a so-called sun-synchronous orbit. Give one advantage and
one disadvantage (for meteorological applications) of a sun-synchronous satellite orbit
compared to a geosynchronous satellite orbit, apart from anything you just mentioned in
6A just above. (10 points)
Advantages: superior resolution; consistent illumination;
Disadvantage: does not return imagery for the same geographic area
except the pole so it is not possible to trace evolution of cloud/storm
systems.
C. The thermal infrared sensors for both the POES and GOES series detects infrared
energy emitted by the earth and clouds passing through the so-called INFRARED or
ATMOSPHERIC WINDOW. Define the “infrared window” and give the approximate
range of wavelengths to which it corresponds. (10 points)
The infrared or atmospheric window is the transparent portion of the water vapor
spectrum through which emitted long wave radiation is allowed free passage to
space. It corresponds generally to the range of wavelengths 7 to 11 microns.
B. The Aqua satellite has an orbit designed to pass different points on the earth’s
surface at two times (12 hours apart) during the day and at night each 24 hour
period. What are those times? __1:30____ PM and ____1:30____ AM. (10 points)
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