biology

Integrated Biosphere Simulator

Integrated Biosphere Simulator is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Integrated Biosphere Simulator rather than just read about it. In short: IBIS-2 is the version 2 of the land-surface model Integrated Biosphere Simulator (IBIS), which includes several major improvements and additions to the prototype model developed by Foley et al. [1996]. IBIS was designed to explicitly link land surface and hydrological processes, terrestrial biogeochemical cycles, and vegetation dynamics within a single physically consistent framework IBIS Functionality The model con…

Key takeaways

Integrated Biosphere Simulator belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Integrated Biosphere Simulator to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Integrated Biosphere Simulator from memory before moving on to harder problems.

Reference excerpt

IBIS-2 is the version 2 of the land-surface model Integrated Biosphere Simulator (IBIS), which includes several major improvements and additions to the prototype model developed by Foley et al. [1996]. IBIS was designed to explicitly link land surface and hydrological processes, terrestrial biogeochemical cycles, and vegetation dynamics within a single physically consistent framework

IBIS Functionality The model considers transient changes in vegetation composition and structure in response to environmental change and is, therefore, classified as a Dynamic Global Vegetation Model (DGVM) This new version of IBIS has improved representations of land surface physics, plant physiology, canopy phenology, plant functional type (PFT) differences, and carbon allocation. Furthermore, IBIS-2 includes a new belowground biogeochemistry submodel, which is coupled to detritus production (litterfall and fine root turnover). All process are organized in a hierarchical framework and operate at different time steps, ranging from 60 min to 1 year. Such an approach allows for explicit coupling among ecological, biophysical, and physiological processes occurring on different timescales.

IBIS Structure The land surface module is based on the land surface transfer model (LSX) package of Thompson and Pollard, and simulates the energy, water, carbon, and momentum balance of the soil-vegetation-atmosphere system. The model represents two vegetation canopies (e.g., trees versus shrubs and grasses), eight soil layers, and three layers of snow (when required). The solar radiative transfer scheme of IBIS-2 has been simplified in comparison with LSX and IBIS-1; sunlit and shaded fractions of the canopies are no longer treated separately. The model now follows the approach of Sellers et al. [1986] and Bonan [1995]. Infrared radiation is simulated as if each vegetation layer is a semitransparent plane; canopy emissivity depends on foliage density. Another difference between IBIS-2 and IBIS-1 and LSX, is that IBIS-2 uses an empirical linear function of wind speed to estimate turbulent transfer between the soil surface and the lower vegetation canopy, and IBIS-1 and LSX use a logarithmic wind profile. The total evapotranspiration from the land surface is treated as the sum of three water vapor fluxes: evaporation from the soil surface, evaporation of water intercepted by vegetation canopies, and canopy transpiration. IBIS simulates the variations of heat and moisture in the soil. The eight layers are described in terms of soil temperature, volumetric water content and ice content. All the process occurring in the soil are influenced by the soil texture and amount of organic matter within the soil. One difference from the physiological processes in the previous version of the model is that IBIS-1 calculates the maximum Rubisco carboxylation capacity (Vm) by optimizing the net assimilation of carbon by the leaf. IBIS-2 prescribes constant values of Vm for the plant functional typed (PFT). To scale photosynthesis and transpiration from the leaf level to canopy level, IBIS-2 assumes that the net photosynthesis within the canopy is proportional to the APAR within it.

Soil Biogeochemistry In the original version of IBIS there was no explicit below ground biogeochemistry model to complete flow of carbon between the vegetation, detritus, and soil organic matter pools. IBIS-2 includes a new soil biogeochemistry module.

Further reading Kucharik, C. J., J. A. Foley, C. Delire, V. A. Fisher, M. T. Coe, J. D. Lenters, C. Young-Molling, N. Ramankutty, J. M. Norman, S. T. Gower, Testing the performance of a Dynamic Global Ecosystem Model: Water balance, carbon balance, and vegetation structure, Global Biogeochem. Cycles, 14(3), 795-826, 10.1029/1999GB001138, 2000. http://www.agu.org/pubs/crossref/2000/1999GB001138.shtml Archived 2007-04-03 at the Wayback Machine Foley, Jonathan A.; Prentice, I. Colin; Ramankutty, Navin; Levis, Samuel; Pollard, David; Sitch, Steven; Haxeltine, Alex, An integrated biosphere model of land surface processes, terrestrial carbon balance, and vegetation dynamics Global Biogeochemical Cycles, Volume 10, Issue 4, p. 603-628. http://adsabs.harvard.edu/abs/1996GBioC..10..603F Integrated Biosphere Simulator Model (IBIS), Version 2.5. Foley, J. A., C. J. Kucharik, and D. Polzin. 2005. Integrated Biosphere Simulator Model (IBIS), Version 2.5. Model product. Available on-line [1] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, U.S.A. doi:10.3334/ORNLDAAC/808 http://daac.ornl.gov/MODELS/guides/IBIS_Guide.html IBIS 2.6 (Integrated BIosphere Simulator). http://nelson.wisc.edu/sage/data-and-models/model-code.php

References

Worked examples

Example 1 — a first encounter with Integrated Biosphere Simulator

Start with the simplest possible case. Write down what Integrated Biosphere Simulator claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Integrated Biosphere Simulator before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Integrated Biosphere Simulator ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Integrated Biosphere Simulator

In research: Integrated Biosphere Simulator appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Integrated Biosphere Simulator in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Integrated Biosphere Simulator is common in secondary-school and first-year university syllabi. It links to neighbouring topics Biological models, Systems ecology, so understanding it makes those chapters shorter.
In everyday life: Look for Integrated Biosphere Simulator outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Integrated Biosphere Simulator in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Integrated Biosphere Simulator means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Integrated Biosphere Simulator out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Integrated Biosphere Simulator in simple terms?

Why does Integrated Biosphere Simulator matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Integrated Biosphere Simulator?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Integrated Biosphere Simulator.