What do thin tree rings indicate

EAS 104 Perspectives of Global Warming

Lab 1: Dendrochronology

Analyzing Tree Rings to Determine Climate Change

Purpose: To utilize monthly average precipitation data to strengthen conclusions about periods of drought or abnormal rainfall from analysis of tree rings

Background: Researchers such as paleoclimatologists or dendrochronologists use tree ring analyses as one tool to reconstruct climate information about the past. They will often reference data from other sources such as historical weather records, and ice core or ocean core samples to support their findings. Since the successful launch of the first weather satellite, TIROS-I in 1960, weather and climate data have been collected from space on a continual basis. More and more scientists in a wide variety of research fields are coming to rely on data gathered by these Earth observing platforms. Tree-ring analysis is considered a method of studying precipitation that oc- curred during the life of the tree. In this lesson, students compare authentic precipitation data to width of tree-rings (either real or simulated) to determine similarities and differences in precipi- tation patterns as indicated by tree-rings, and precipitation patterns indicated by satellite data for the same time period. Note: This lesson is designed to facilitate student acquisition of the skills and knowledge necessary for accessing and utilizing NASA data sets to further their science and math competencies while engaging them in activities that reflect the processes of scientific in- quiry as conducted by individuals in a growing number of careers.

Task 1: Tree Ring Analysis (20 points)

Use the simulated tree-ring plots. Notice the thickness of the rings. The thickness of the rings indicates the quality of the growing conditions during that season. For example, a thicker ring would most likely indicate that water was plenteous during that growing season. To determine the age of the tree, begin counting each ring only once. Don’t count the bark (outer coating of the tree) and the inner core as rings. Record the number of rings you have counted. This corre- sponds to the number of years the tree was alive. To determine the year in which the tree was planted, subtract the number of dark rings from the year in which it was cut. Complete the fol- lowing for each tree (all 4 trees):

*Include your Full Name, Course Title, Lab Section, and Lab Assignment Number on the top of the first page of your submitted work (4 points).

Using the information from 4 different tree ring plots to fill in the table with following cate- gories: (15 points)

●Planted Year (= year harvested - total tree ring): For example, 2006-24=1982 (Jackson, MS);

●Count the selected Thin Tree Ring starting with from the core;

●“Average Daily Precipitation” is labeled on tree ring plot;

●Year of selected Thin Tree Ring (= Planted Year + Selected Thin Tree Ring): For example, 1982+5=1987 (Jackson, MS);

● “Satellite Precipitation” is mentioned in Task 2.

Task 2: Satellite Precipitation Plot

Find the average precipitation (in millimeters per day, mm/day) for the year you have selected, for each Tree Ring, in Task I ,and enter the information below. Then, find the average precipita- tion (in mm/day) for the year you have selected, and enter the information below.

Tree Location Jackson, MS Columbus, MO Boston, MA Seattle, WA

Total Tree Rings 24

Year Planted 1982

Average Daily Precipitation(mm/day)

3.73

Select Thin Tree Ring 15th Ring 1st Ring 12th Ring 5th Ring

Year Below Average 1997

Satellite Precipitation(mm/day)

3.1

1. Jackson, Mississippi Satellite Plot:

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● “Satellite Precipitation(mm/day)”: Look for the precipitation value for the year of selected Thin Tree Ring in the satellite plot:

●For example, precipitation = 3.1 mm/day for 1997 (Jackson MS).

2. Columbia, Missouri Satellite Plot:

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3. Boston, Massachusetts Satellite Plot:

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4. Seattle, Washington Satellite Plot:

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Task 3: Answer the following questions in full sentences (3 points):

Q1: Did the NASA Satellite Precipitation data confirm your tree ring analysis for each location? Describe yes or no (1 point).

Q3: Can you suggest data sets for other parameters that you could check that might support ei- ther the tree ring or the satellite data, if they do not agree? (1 point)

Q4: Comparing between the tree ring analysis and the satellite plot, which one do you think that best reflects the precipitation change within a year? (1 point)