GLOBE Carbon Cycle: Modeling

University of New Hampshire: Jennifer Bourgeault, Rita Freuder, Lara Gengarelly, Mary Martin, Scott Ollinger, Sarah Sallade, Annette Schloss, Haley Wicklein

Czech Republic: Jana Albrechtova, Kateřina Čiháková, Zuzana Lhotakova, Barbora Semeráková, Premek Stych, Dana Votapkova  

GLOBE Program Office: Gary Randolph

A Simple System: Paper Clip Factory

Input FluxPer unit time

Output FluxPer unit time

Pool, Stock

Production

Purchases

Store Inventory

What is a Model?The American Heritage® Dictionary of the English Language, Fourth Edition

*mod·el  (n).

1. A small object, usually built to scale, that represents in detail another, often larger object.

2. A preliminary work or construction that serves as a plan from which a final product is to be made.

3. A schematic description of a system or phenomenon that accounts for its known or inferred properties and may be used for further study of its characteristics.

4. One that serves as the subject for an artist, especially a person employed to pose for a painter, sculptor, or photographer.

5. A person employed to display merchandise, such as clothing or cosmetics.

Models are tools and concepts that help us Models are tools and concepts that help us understand, explain, and predict systems that are understand, explain, and predict systems that are too complex or difficult to observe, or to too complex or difficult to observe, or to

comprehend on our own.comprehend on our own.

----

Models are simplifications of reality.Models are simplifications of reality. ----

““The most useless scale for The most useless scale for a road map is 1:1”a road map is 1:1”

Better Working Definitions

Modeling: Paper Clip Factory

Installing the iSee Player

1. Download the isee player from the isee systems website. www.iseesystems.com

1. Then install.

Accessing and Opening: the iSee Player Tutorial &

Models

Open the isee player application from your hard drive or the GLOBE CD.

•To open the iSee Player Tutorial: FileOpen, then navigate to the isee player folder select the Tutorials folderisee_Player_tutorial.STM

•To open a different model go to: FileOpen, then you can select your desired model from its current location on your computer.

iSee Player Tutorial

• Step by step instructions for how to use the isee player

• Meant for first time users and as a refresher

• Uses the Paperclip Factory as the example

• Available in the “Tutorials” folder of the downloaded iSee Player

• Synthesize existing knowledge in ways not possible using human CPU (Cranial Processing Unit).

• Forecast future conditions, often with policy- relevant goals.

• Examine the fundamental behavior of a system.

• Identify gaps in current knowledge and to guide future research.

• Generate hypotheses (as opposed to predictions).

““The purpose of models is not to fit the data but to sharpen the The purpose of models is not to fit the data but to sharpen the questions”. -S. Karlinquestions”. -S. Karlin

Why Use a Model?

Modeling Themes: In the standards

• Models as tools

• Scales - time, size, numbers

• Systems - How do systems work?, Connecting system parts

• Cycling in the Earth system

• Understand how human actions…

Biomass-NPP Model Activity

Unit Essential Question

How are models useful in understanding the carbon cycle?

Student Outcomes

•Students use a computer model to analyze model output graphs and tables.

•Students will define biomass and relate it to carbon storage.

•Students will identify the relationship between inputs and model results by changing variables one at a time.

•Students will compare and contrast model run results for their own location with at least one other biome.

•Students will describe the activity results by correctly using basic modeling concepts, such as flow (inputs and outputs from growth and death), standing stock (biomass), turnover rate (flow ÷ stock), residence time (stock ÷ flow) and equilibrium, in their worksheet answers and class discussion.

Biomass-NPP Model

POOL (stock)(stock)

Vegetation Biomass

INPUTS (Total Growth)

OUTPUTS (Mortality + Total Litter)

FluxFluxFluxFlux

General Model Diagram

Biomass-NPP Model: Input Flux

Figure 2. The relationship between net primary production and (a) annual temperature and (b) annual precipitation for ecosystems around the world. From Leith 1975.

Figure 1. The global distribution of major ecosystems with respect to mean annual temperature and mean annual precipitation. From Ollinger 2002, modified from Whittaker, 1975.

What factors influence ecosystem vegetation growth? Locally? Globally?

Biomass-NPP Model: Output Flux

What factors determine ecosystem mortality and litterfall?

In the model we use: turnover rate.

TR: is the rate at which living plant material dies and becomes plant litter. This is determined as the ratio of dead plant litter produced in a given year to the total amount of plant biomass present.

Model Fluxes: Click to find climate & biome for your site (use lat-lon)

Model Fluxes: Temp, Precip, Biome

Foliar Nitrogen - Biomass Model

Access the Activity at: http://serc.carleton.edu/eet/globecarbon/index.html

EET Chapter: Understanding Carbon Storage in Forests

Each EET chapter provides teachers and/or students with direct practice for using scientific tools to analyze Earth science data. Students should begin on the Case Study page.

In this EET activity, you'll learn about forest biomass and its role in carbon storage. You'll compare field collected data with results produced by a forest biomass model to understand the process and challenges scientists face when doing terrestrial carbon cycle research.

This chapter was developed as a collaboration between University of New Hampshire scientists and EET curriculum developers

STANDING STOCK (Pool)(Pool)

Forest Biomass

INPUTS (Wood Growth)

OUTPUTS (Mortality +

Woody Litter)FluxFlux

FluxFlux

~400 g/m2 * yr ~2% / year

Foliar Nitrogen - Biomass Model

OUTPUT = (?)

2% per year

(Current Biomass * 0.02)

• Remember 50% of biomass by weight is carbon!!!

Foliar Nitrogen - Biomass Model

Foliar Nitrogen - Biomass Model

WoodBiomass(t) = WoodBiomass(t - dt) + (WoodNPP - WoodLitter - Harvest) * dtINIT WoodBiomass = 0

INFLOWS:WoodNPP = 3.9 + 200*Foliar_Nitrogen

Foliar Nitrogen - Biomass Model

OUTFLOWS:WoodLitter = WoodBiomass * WoodLossHarvest = IF (TIME = HarvYear) then (WoodBiomass * HarvIntens) ELSE (0)BiomassIncrement = WoodNPP - WoodLitter Foliar_Nitrogen = 2HarvIntens = 0HarvYear = 0WoodLoss = .02

• Basic questions: Students learn to read model output graphs and tables.

• Changing 1 variable at a time: Students make connections between model inputs and their effect on model outputs.

• Working with 2 variables: Students develop and understanding of the science in the model.

• Thought questions: Students will understand forest biomass and can relate it to carbon storage.

• Scenarios: Students create model scenarios based on scientific ideas and previous questions for other students to work through.

Foliar Nitrogen - Biomass Model