Lab 1 GEOS______
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University of British Columbia *
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Course
102
Subject
Geography
Date
Apr 3, 2024
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Pages
7
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GEOS 102 Our Changing Environment: Climate and Ecosystems
PART 1: Daily Radiation Budget [12 marks]
We will be using the SURFRAD network website to access radiation data from 2 monitoring sites in the
United States. The network provides long-term, continuous measurements of the surface radiation budget
for multiple sites, and available data includes incoming and reflected shortwave radiation, incoming and
outgoing longwave radiation and net radiation. This data can be downloaded and used to inform climate
research. Also available on the website are photographs of the sites, which can be used to gain insight on
radiation budgets.
Firstly, follow the instructions in the document:
Accessing the SURFRAD network
. This document, will
show you how to obtain the data and graphs needed to complete the following questions.
Note: For date selection in step 3, choose the date following date which applies to you (based on the last 2
digits of your student number):
0-25 : June 01 2019 26-50 : July 05 2018
51-75 : May 28 2018
76-99 : August 05 2019
Fort Peck, MT
Q1.
(
upload a screenshot of the graph, acquired by following the above instructions (Accessing the
SURFRAD dataset), to canvas
)
Answer the following questions for the graph of Fort Peck, MT:
Q2.
Name 2 variables that could affect the value of SW ↓ and SW ↑. [2]
-
Time of day
-
Temperature
-
Sunlight
Q3.
Why do SW ↓ and SW ↑ have similar (if not the same) values between 3 and 11 UTC? [1]
-
During the hours of 8:00 PM to 4:00 AM there is less energy, the temperature is low and constant
which is why the graph is flat.
Q4.
Why is LW ↑ greater than LW ↓? [1]
-
The majority of the energy got reflected and reemitted into the atmosphere; the heat resulting from the
absorption of incoming SW radiation is emitted as LW radiation. The LW ↑ comes from the surface of
the earth and the LW ↓ comes from the atmosphere, the temperature of the surface of the earth is
greater than the temperature in the atmosphere.
Q5.
Describe the diurnal pattern of total net radiation (Q*), and state which component of the radiation
budget exerts the most control over Q*. [2]
-
Q* goes down slightly from about 260 watts/m^2 to -60 watts/m^2 between 0 to 3 UTC and stays
almost constant around -60 watts/m^2 between 3 to 11 UTC. Between 11 to 13 UTC, Q* slowly
increases to 90 watts/m^2. From 13 to 15.5 UTC, Q* increases rapidly from -60 watts/m^2 to 500
watts/m^2. Between 15.5 and 18.5 UTC, Q* slightly increases to around 680 watts/m^2. From 18.5
UTC to 20.5 UTC, Q* drops drastically but increases back to around 780 watts/m^2. From 20.5 UTC
to 24 UTC, Q* with lots of fluctuation unevenly drops to just over 0 watts/m^2.
-
Downwelling solar exerts the most control over the total net radiation.
Desert Rock, MV
Q6.
(
upload a screenshot of graph, acquired by following the above instructions (Accessing the
SURFRAD dataset), to canvas
)
Q7.
State 2 differences between the two sites and suggest some reasons for these differences in terms of
climate and environment. [2]
-
First, in Desert Rock, Nevada between 13 and 15.5 UTC the downwelling solar, upwelling solar, and
total net radiation is more stable compared to Fort Peck, Montana where there is lots of fluctuation
between 13 and 15.5 UTC. Second, between 0 and 2 UTC in Fort Peck, Montana the decline in the
downwelling solar and total net radiation is more stable than Desert Rock, Nevada and there is much
less fluctuation in watts/m^2.
-
In Fort Peck, Montana the temperature difference during the day and night is much greater compared
to Desert Rock, Nevada. This temperature difference indicates instability in regards to sunlight, which
can cause fluctuation of the radiation at Fort Peck between 13 and 15.5 UTC. Aswell, between 0 to 2
UTC, the temperature decreases much faster and less stable in Desert Rock compared to Fort Peck.
Calculating albedo and net radiation (see more in the endnotes)
1.
Download the
Fort Peck radiation data spreadsheet
containing radiation data for a day in July in Fort
Peck. Fill in the columns for albedo and net radiation using the following equations:
Netradiation
(
𝑸∗
) = (
?
↓ +
?
↓)– (
?
↑ +
?
↑) = (
?
↓ −
?
↑) + (
?
↓ −
?
↑) (1)
The albedo or reflectivity (α) of a surface refers to the proportion of incident short-wave radiation which
is reflected by the surface:
Albedo
(α)
=
?
↑ / ?
↓(2)
Q8.
At what time of day does the maximum Q* occur? [1]
-
The maximum Q* occurs at 1:01:01 PM with 669.4 watts/m^2
Q9.
What is the value of albedo at 0900 and 1700 hours? Express answers in percentages (e.g. 10% not
0.1). Explain how albedo changes between these hours. [3]
-
0900 hours = 25%
-
1700 hours = 30%
-
Between 0900 hours to 1700 hours, the albedo increases from 25% to 30%.
PART 2: CO2, Temperature, and Climate Change [12 marks]
Examine the updated version at the end of this document (in endnotes; Fig. 2), downloaded from the
NOAA web-site: https://www.esrl.noaa.gov/gmd/ccgg/trends/. This famous graph is often referred to as
the “Keeling Curve” after the name of first author who originally published the data. It represents
atmospheric CO2 concentration atop Mauna Loa, Hawaii (in parts per million, ppm).
Q10.
List 4 processes/activities that are responsible for the peaks and troughs observed in the keeling
curve (2 for each). [1]
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