Geology Reference
In-Depth Information
there in 1976, indicating that the air temperature has
warmed. We know that the temperature of the atmosphere
changes by 0.7° C for each rise in elevation of 100 meters
(0.007° C/l meter). This is the atmospheric lapse rate. Using
your answer in Question 8 and this lapse rate, calculate the
temperature change that took place at Summit Dome
between 1976 and 1991.
13.
To help understand the impact of even small changes in
temperature, we now look at "the year without a summer."
Volcanic events are recorded in ice cores as seen in Figure 18.1b
where the eruption of Mt. is shown by an ash layer. On
April 5, 1815, Mount Tambora in Indonesia began erupting
and injected ash and gases (e.g., H
2
0, CO2, HC1,
SO2,
N2)
into the stratosphere. Some of these gases (for instance, HC1)
have the potential to affect the ozone
(O3)
layer; most act to
enhance the greenhouse effect, but sulfate
(SO4)
droplets in the
stratosphere can increase cooling. In 1816 temperatures
declined by 1° C in the northern hemisphere (Bryant, 1991).
The following description, modified from the Berlin, Ohio,
Sesquicentennial History (1966) captures the conditions in this
area of the Midwest in the "year without a summer."
10.
Study the photos (Figure 18.3) of the Qori Kalis Glacier,
the largest outlet glacier from the Quelccaya Ice Cap. What
has happened to this glacier between 1978 and 2000?
11. a.
Study the map (A) in Figure 18.4, which illustrates
positions of the Quori Kalis glacier terminus mapped from
aerial photos taken in 1963 and terrestrial photos taken in
1978, and later. What is the approximate straight-line dis-
tance between the maximum position in 1963 (near the 1 in
the date 1963 in the figure) and the center of the
average
posi-
tion of the terminus in 1991?
In each of the 12 months of 1816, ice and frost were
experienced in Ohio, the Midwest, and New England. The
month of January was very mild, and only a few cold days
in February. March was moderately cold; April came in
warm, but changed to snow and cold by the end of the
month.
May was so cold that all buds and fruits were frozen and
ice formed an inch thick. Corn that came up was frozen,
replanted and frozen again. Other crops were likewise
frozen. June was the coldest known with frost, ice and snow.
Snow fell to a depth of10 inches in Vermont, 7 inches in
Maine, and 3 inches in Massachusetts and New York.
Frost was common in July. A half-inch of ice was
recorded in August; the stunted corn was fed to cattle as
fodder. September began cold with snow in New York on
September 11. New Berlin was mild in mid-September, then
cold, frost and 1/4 inch of ice. Frost and ice were common in
October; November was stormy with much snow. December
was mild and comfortable.
b.
From your measurement, what is the average annual
rate of change for this period (1963-1991) in m/yr?
c.
Study the inset graph in Figure 18.4. Has the rate of
retreat of the glacier increased or decreased since 1978?
12. a.
Determine the rate of retreat from 1991 to the most recent
position of the end of the glacier as shown in Figure 18.5.
Switzerland was also experiencing unusual weather in the
summer of 1816. The rainy and overcast weather was a factor in
FIGURE 18.3
Terminus of the Qori Kalis outlet glacier of the Quelccaya Ice Cap. Note changes in margin, snow, debris cover, and
profile from 1978 (A) to 2000 (B). (From L. Thompson, pers. comm., 2008; used with permission)
