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— | plantmodel [2017/11/10 09:09] (current) – external edit 127.0.0.1 | ||
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+ | ====== [PLANTMODEL] Section ====== | ||
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+ | ===== Purpose ===== | ||
+ | To calculate the transpiration of plants, it is necessary to know the actual stomata resistance.\\ | ||
+ | The stomata are active components of the plant system and react on environmental impacts such as solar input, air temperature and water availability in the soil. | ||
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+ | ENVI-met provides two methods for calculating the stomata resistance: A simple approach based on the work of Deardorff (1978) and a very sophisticated approach called A-gs model following the work of Jacobs (1994) (for exact references please refer to the papers available on the UNCONVERTED WINHELP MACRO:! '' | ||
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+ | The Deardorff approach scales an explicitly given maximum value of the stomata resistance with respect to the solar input and the water availability whereas the A-gs model calculates the photosynthesis rate of the plant and concludes from that to the C02 demand and finally to the state of the stomata. | ||
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+ | **We recommend the use of the A-gs model as it is more plant physiologically based than the Deardorff model.** | ||
+ | |||
+ | To choose the model, use the [PLANTMODEL] section: | ||
+ | |||
+ | < | ||
+ | 00: [PLANTMODEL] _____________Settings for plant model | ||
+ | 01: Stomata res. approach (1=Deardorff, | ||
+ | 02: Background CO2 concentration [ppm] =350 | ||
+ | </ | ||
+ | |||
+ | |||
+ | ===== What do the lines mean? ===== | ||
+ | |||
+ | === 01: Stomata res. approach (Default 2, A-gs) === | ||
+ | Select the stomata resistance model to be used in the simulation. | ||
+ | |||
+ | === 02: Background CO2 concentration [ppm] (Default 350 ppm) === | ||
+ | Sets the background CO2 concentration. Only needed for the A-gs model.\\ | ||
+ | Remark: If other sources in the model are of the CO2 type, they will add up to the CO2 concentration. | ||