Keeling Data Set Modern Atmospheric

Homework Assignment: Keeling Data Set
Modern Atmospheric CO2 Record (39 points)
Monthly atmospheric CO2 data an atmospheric monitoring stations, including the Mauna Loa
Observatory, Hawaii.
You will need access to excel to complete this exercise. If you don’t have it, you can download
office for free here as a CSUEB student:
https://www.csueastbay.edu/news/2015/06/06102015.html
All questions will need to be answered and uploaded into a link in Course Materials Week 7/8.
Unless otherwise stated, all questions are worth 1 point each.
I. Introduction
The measurements of atmospheric carbon dioxide (CO2) concentrations at the Mauna Loa
Observatory are derived from the Scripps Institution of Oceanography's continuous
monitoring program. This record constitutes the longest continuous record of atmospheric
CO2 concentrations available in the world. Monthly averages* of CO2 in water-vapor-free
air are given from March 1958 through present, except for a few interruptions.
A. Atmospheric CO2 Data
Open the Scripps data file that I have attached here. Open it in excel. Familiarize yourself
with the location of the station where the data was collected by checking out the related web
site: https://scrippsco2.ucsd.edu/data/atmospheric_co2/primary_mlo_co2_record.html Note
that there is one parameter, CO2, measured monthly. This website is best accessed NOT
USING SAFARI.
Task 1: Using the web page, scroll down to the Figure of monthly average CO2. Let’s examine
this data set. Answer these questions about the data. I know these are simple questions, but
the trends have significance.
1: What units are CO2 measured in?
Micro-mol CO2 per mole (ppm)
2: What are the maximum and minimum recorded CO2 for the timeframe 1958 – 2020?
Maximum= 414.83 [ppm]
Minimum= 313.21

3: Are the values increasing or decreasing with time?
The values are increasing with time
4: Are the data smooth or ragged as it increases or decreases?
The data are ragged as they increase
5: Do the data have a pattern, other than just continually going up?
The data has pattern other than continually going back. It increases to some maximum
value then decrease then the pattern repeats itself
Task 2:
6: What does the word “oscillation” mean?
Moving back and forth in a regular rhythm
7: What does it mean when we say this graph has regular, short term oscillations?
The data seems to increase to a maximum value and decrease to a minimum value before
repeating the same trend. This increase and decrease happens over a short time span.
Explore what is the cause of the short-period oscillation of CO2? (multiple parts to this
question):
To explore the answer to Q2c, you are to create a chart using the data in the excel file showing
ONLY the last 3 years of the CO2 records SPECIFICALLY January 2017 through January
2020. Recall that this is an "xy scatter plot" and NOT a "line plot" when using Excel's chart
function.
The x-axis should be date and the y-axis concentration of CO2. Note that the months are
listed in the documents as numbers 1= January, 2= February, etc, AND is translated into a
decimal of each year 2000.041 = Jan 2000, etc. Please use the “plotting in excel” document to
help you, and start early so you can ask the professor for help if needed.
This chart should show an xy scatterplot of Date and CO2.
8: Upload your chart to the homework (3 point)

2016.5 2017 2017.5 2018 2018.5 2019 2019.5 2020 2020.5
396.00
398.00
400.00
402.00
404.00
406.00
408.00
410.00
412.00
414.00
416.00
A Scatter Plot CO2 Concentration against Date in Dec-
imal Months
Decimal Date
concentration of CO^2(ppm)
9: How long is each oscillation? (From minimum to minimum, you can stretch out the graph
to help you see this)
1 year
10: What month(s) do CO2 maxima occur?
May
11: What month(s) do CO2 minima occur?
September
Think about seasonality and how it relates to CO2 uptake through photosynthesis and ocean
absorption. When plants are active and have adequate water, they take CO2 out of the
atmosphere. View this animation
(https://earthobservatory.nasa.gov/global-maps/MOD17A2_M_PSN) showing monthly
variations in net primary productivity and read the explanation.
12: What is Net Primary Productivity (NPP)?
NPP refers to the difference between how much carbon dioxide is taken by vegetation during
photosynthesis and how much carbon dioxide is released during photosynthesis.
13: What are the units of NPP?
Grams per square meter per day
14: What does NPP have to do with Carbon uptake from the atmosphere?
The greater the carbon uptake from the atmosphere the greater the NPP value
15: What does a negative number mean?
A negative value implies that respiration or decomposition is greater than carbon absorption
leading to more carbon release to the atmosphere compared to plant uptake.