Date Due: Thursday, 26 June 2004
The total maximum points were 60. Point distribution for each question noted below.
1a. The barometric pressure associated with one standard
atmosphere at mean sea level is
[you
may round to nearest whole number]:
(5 pts - 1 each)
|
1 atmosphere of pressure is equivalent to: 29.92 (or 30) inches of mercury 76.0 centimeters of mercury 14.7 (or 15) pounds per square inch (psi) 1013.25 (1000) millibar (mb) 34 feet of water |
1b. The lowest recorded sea level corrected pressure
in the world was ________. [Please include units!]
|
Lowest pressure: 870 mb = 25.68 inches of mercury |
The highest recorded sea level corrected pressure in the world was ________. [Please include units!]
|
Highest pressure: 1083.8 mb = 32.01 inches of mercury |
The range between the
record lowest and highest sea level corrected pressure (above)
is approximately ________.
|
The range: Range = (High - Low) |
(4 pts - 1,1,2)
1c. What is the weight exerted by the atmosphere upon the
flat, horizontal roof of a 25-foot by 50-foot building? [Assume
standard sea level conditions; English units may be used here]. Clearly
show your work for partial credit!
|
From Pressure = Weight / area, we can determine that Weight = Pressure x area Pressure = 15 pounds per square inch (approx.) Area = 25 ft x 50 ft = 1250 sq. ft. Since 1 sq. ft. = 144 sq. in. (count them - since 12 inches on each side of the square), then 1250 sq. ft. = 1500 x 144 = 180,000 sq. inches. Then: Weight = 15 lb per sq. in x 180,000 sq. in. = 2,700,000 lb or 1350 ton (If 14.7 psi were used, the weight would be 2,646,000 lb or 1323 ton) Note that units check too! While this answer may sound large, the roof does not collapse from the weight exerted by the atmosphere since the air pressure is pushing on the roof in all directions. |
(5 pts)
1d. A football fan brought an aneroid barometer to Mile High
Stadium in Denver (elevation of 1 mile) and made a reading of 835 mb.
What would be the approximate sea level corrected pressure if we
assumed that the pressure decreases at approximately 1 mb per 10 meters
ascent through the atmosphere?
|
Mile High Stadium in Denver is 5280 ft above mean sea level (MSL), or 1600 m MSL. Since the air pressure is assumed to decrease at a rate of 1 mb per 10 m, the pressure at the stadium should be 160 mb less than at the mean sea level directly below the stadium. Because the observed station (or in this case, stadium) pressure was 835 mb, by descending to sea level, the pressure would increase, or at the stadium would be [840 + 160] mb or 995 mb. |
(4 pts)
How does this sea level pressure that you calculated compare with
the standard sea level pressure?
|
The sea level pressure below Denver on this particular day (995 mb) is slightly less than a typical value of sea level pressure (1000 mb) and it is 18 mb less than standard sea level pressure (1013 mb). |
(3 pts)
2. Current Weather on the Web (6 pts.)
See http://www.aos.wisc.edu/~hopkins/aos100/homework/s04hmk1k.htm
This portion of the homework was designed to have you access current
weather and climate information from a local National Weather Service
Office on the Internet. Any "reasonable answer" that fell within
the range of values for the past week's weather in Madison was
accepted.
3. Convert the following temperature readings:
|
41ºF = 5ºC = 278 K -40ºC = -40ºF = 233 K 258 K = -15ºC = 5ºF Note: Be careful of signs! If the negative sign does not appear in your answer where appropriate, the answer is not correct. |
(6 pts)
4a. The record highest temperature for Madison, WI was 107ºF
(41.7ºC) on 14 July 1936, while the record low was -37ºF
(-38.3ºC) on 30 Jan 1951. What is the range of
Madison's extreme temperatures?
|
Range = (High - Low) = 107ºF - (-37)ºF = 144 Fahrenheit degrees. |
(1 pt)
4b. Compare these record temperatures and range with those of
the United States and the world.
[Please include units!]
The following values were obtained from the links off
the Lecture #3 (Temperature) page:
For the United States:
"All-time temperature
extremes by state "
and for the world: "observed extremes
in temperature by continent (from NCDC)".
|
|
Record High |
Record Low |
Range = (High - Low) |
|
United States |
134ºF or |
-79.8ºF or -69.7ºF or |
213.8ºF or 203.7ºF or |
|
World |
136ºF or |
-129ºF or |
265ºF or |
(6 pts)
5. The National Weather Service at Madison reported the
following information for individual days during this past January. The
"normal" high and low temperatures for these days are also included and
represent the 30-year averages for the 1971-2000 climatological
interval.
|
DAY |
Observed |
Normal |
|
|
|
|
|
26 Jan 2004 |
[22 + 15]/2 = 19ºF |
[25 + 9]/2 = 17ºF |
|
28 Jan 2004 |
[10 + (-6)]/2 = 2ºF |
[26 + 9]/2 = 18ºF |
(12 pts.)
i.) Actual Heating Degree Day Units:
|
HDDU = [65ºF - Average daily temperature] |
|
26 Jan 2004: 65ºF - 19ºF = 46 HDDU |
|
28 Jan 2004: 65ºF - 2ºF = 63 HDDU |
ii.) Normal HDDU
|
26 Jan: 65ºF - 17ºF = 48 HDDU |
|
28 Jan: 65ºF - 18ºF = 47 HDDU |
iii.) How would the amount of energy required for space heating on each of those dates compare with that of the climatological (or "normal") average for the corresponding dates? Explain your reasoning.
|
The second day, 28 January 2004 would require more energy for
heat. |
(4 pts.)
Latest revision: 27 June 2004 (2100 UTC)
Produced by Edward J. Hopkins, Ph.D. Department of Atmospheric and Oceanic Sciences University of Wisconsin-Madison, Madison, WI 53706 hopkins@meteor.wisc.edu
URL Address: aos100/homework/s04hmk01a.html