Midterm exam 1
Tuesday, January 23, 2001
(1) It is often observed that
delicate plants like wildflowers, which need plenty
of moisture,
grow on north facing slopes, while plants like cactus and sagebrush,
which need
very little moisture, tend to grow on south facing slopes. Explain.
(10
points)
(2) In a make-believe solar system
there is a planet similar to the Earth except
that its
orbit about its sun is highly elliptical. At its closest approach
to its
sun the
distance is 1 A.U. (the same as Earth's mean distance from its sun), but
its orbit
ranges out as far as 4 A.U.
(a) Compare
the relative amounts of solar radiation that it receives at the
outermost and innermost points in its orbit.
(b) If
the albedo of the planet is fixed, and if the planet is always in radiative
equilibrium, by what fraction does its effective radiating temperature
vary as it
orbits its sun?
(c) In making
this comparison, should you use the Fahrenheit, the Celsius, or the
Kelvin temperature scale?
(10
points; 4, 4, 2)
(3) (a) Venus is closer to the sun
than the Earth, yet it has a lower effective
radiating temperature than the Earth does. Explain.
(b) Although
Venus has a lower effective temperature than Earth, its surface
temperature is much higher. Explain.
(c) The
brightness of Venus in the night sky bears no relation to its effective
radiating temperature. Explain.
(15
points; 5, 5, 5)
(4) The United States experiences
its coldest weather at the time of year when the
earth
is closest to the sun. Explain this apparent paradox. (10 points)
(5) (a) When an infrared radiometer
like the one we examined in class is pointed
upward at clear sky it reads a lower temperature than when it is pointed
at a
cloud layer. Explain.
(b)
Is the radiometer likely to read higher when pointed at a high cloud layer
or a low cloud layer?
(c)
Are there any conditions under which it could read higher when pointed
upward at a cloud layer than when pointed downward toward the ground?
(10
points; 4, 4, 2)
(6) On a summer afternoon, the vertical
temperature profiles at Seattle and Yakima
(located
on the eastern side of the Cascades) are identical above the 1-kilometer
level,
where the temperature at both locations is 20 C (68°F). Down
close to
sea-level,
the temperature at Seattle, which is experiencing a seabreeze from
Puget
Sound is also 20 C, whereas at Yakima it is 28 C.
(a)
What are the lapse rates (expressed in degrees C per kilometer) at the
two locations?
(b)
If hot air balloons were launched at the two cities, which one would require
more
heating in order to enable it to rise to the 1 km level?
(c)
What is the ratio of the amounts of heating required at the two locations?
[Hint: assume that due to expansion, the air in the balloon would cool
at a rate of
10°C per kilometer if it weren't heated.]
(10
points; 4, 4, 2)
(7) If summer rainfall is below normal
for an extended period of time, vegetation
tends
to wilt or die, As the vegetation wilts or dies, less moisture evaporates
from
the underlying soil. If there's less evaporation, the air is likely
to be
drier
and weather systems are likely to produce less rain when they pass through.
Is
this a positive or a negative feedback loop? Explain your answer.
(10
points)
(8) Name the four major components
of the Earth System and give one example of how
each
of the four components is influenced by one of the other components.
(10
points)
(9) Match the following climate statistics with the locations. Consider the latitudes carefully. (5 points)
A Tumaco, Colombia (2°N) ( )(10) Match the following climate statistics with the locations (5 points)
B Darwin, Australia (12°S) ( )
C Bangkok, Thailand (14°N) ( )
D Calcutta, India (23°N) ( )JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
1) T(°F) 84 84 84 84 82 81 79 81 82 86 86 84
r(mm)386 312 254 97 15 3 -- 3 13 51 119 2392) T(°F) 79 82 84 86 86 84 84 84 82 82 81 79
r(mm) 5 28 28 58 132 152 175 234 356 252 46 33) T(°F) 64 70 79 84 86 84 82 82 82 81 72 64
r(mm) 10 28 36 21 127 284 307 292 228 109 13 54) T(°F) 79 79 79 80 80 79 79 79 79 79 79 79
r(mm)428 297 243 370 441 304 195 185 185 150 124 177
A Perth, Australia (32°S) west coast ( )
B San Diego, CA (32°N) west coast ( )
C Tokyo, Japan (36°N) east coast ( )
E Mexico City (19°N) alt. 7000 ft ( )JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
1) T(°F) 56 58 58 62 63 66 70 72 70 66 62 58
r(mm) 48 38 39 20 4 1 -- 2 3 9 31 442) T(°F) 39 39 44 56 62 70 75 79 74 62 52 43
r(mm) 48 63 106 135 147 165 142 153 234 208 97 563) T(°F) 74 74 72 66 62 58 56 56 58 64 68 64
r(mm) 8 10 20 43 130 181 170 145 88 56 21 134) T(°F) 54 56 61 64 68 66 65 65 64 61 58 56
r(mm) 5 8 13 18 48 104 114 109 104 40 13 8
(11) Match the following climate
statistics with the locations (5 points)
A Seattle, WA (47°N) ( )
B Fairbanks, AL (65°N) inland ( )
C Bismarck ND (47°N) mid-continent ( )
E San Francisco, CA (38°N) coastal ( )JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
1) T(°F) 39 41 44 50 56 60 64 64 59 52 46 43
r(mm)125 97 79 61 46 33 15 18 44 71 122 1402) T(°F) 8 14 25 43 54 64 72 70 58 46 28 16
r(mm) 10 10 20 31 51 86 53 43 31 23 15 103) T(°F) 52 54 54 56 58 59 59 59 62 61 58 52
r(mm)101 88 96 33 13 3 -- -- 5 18 33 1044) T(°F)-12 -2 12 28 46 59 61 56 44 25 3 -10
r(mm) 23 13 10 8 18 35 45 55 27 23 15 13