Homework 3
Global Climate - ATM 5 - Winter 2000

Name:                          _____________________________________________
TA's Name:                   _____________________________________________
Discussion (day/time):
_____________________________________________

Date assigned:   January 26, 2000
Date due:   Wednesday, February 2, 2000 by 5:00 p.m.
Instructor:   Terry Nathan

Directions: Answer all questions. Write your name, your TA's name, and the day and time of the discussion section you attend at the top of this page and on each page you submit. Attach this page as the first page of the homework assignment and staple all pages together. The point value for each item is shown in parentheses. Work individually.


PROBLEM 1 (20)

Explain how and why each of the following will change as a parcel of air with an unchanging amount of water vapor rises, expands, and cools: a) absolute humidity; b) relative humidity; c) actual vapor pressure; d) saturation vapor pressure.

PROBLEM 2 (15)

In the winter of 1844, John C. Fremont and Kit Carson led an expedition that crossed the Sierra Nevada Mountains near present day Carson Pass, which is located about 15 miles south of Lake Tahoe and only several miles east of Kirkwood Ski Resort. Despite experiencing tremendous hardships, including having to eat their pet dog and some of their horses, Fremont recorded much scientific data, including the elevation of various points along their trail. On February 20, 1944, Fremont writes: "The temperature of boiling water gave for the elevation of the encampment nine thousand three hundred and thirty-eight feet above the sea."

Explain how Fremont was able to estimate his elevation based on the boiling point of water. Your answer must include a discussion of saturation vapor pressure.

PROBLEM 3 (10)

The data given in the chart below represents the dew-point temperature (Td) and expected minimum temperature (Tmin) near the ground for various clear winter mornings in a southeastern city. Assume that the dew-point temperature remains constant throughout the night. Answer the following questions about the data.

(a)       On which morning would there be the greatest likelihood of observing visible frost? Explain.
(b)       On which morning would you probably only observe dew on the ground? Explain.

    Morning 1Morning 2Morning 3Morning 4Morning 5
Td350F200F340F250F380F
Tmin400F270F320F 240F 350F

PROBLEM 4 (10)

If the clouds overhead are moving from north to south, would the upper level center of low pressure be to the east or west of you? Explain how you obtained your answer.