A Representation of Variable Root Distribution in Dynamic Vegetation Models
نویسندگان
چکیده
Root distribution is treated as a static component in most current dynamic vegetation models (DVMs). While changes in leaf and stem biomass are reflected in leaf area index (LAI) and vegetation height via specific leaf area (SLA) and allometric relationships, most DVMs assume that changes in root biomass do not result in changes in the root distribution profile and rooting depth. That is, the fraction of roots in soil layers, which is used to estimate transpiration, is taken to be constant and independent of root biomass and/or vegetation age. A methodology for parameterizing root distribution as a function of root biomass is proposed for use in dynamic vegetation models. In this representation, root distribution and rooting depth evolve and increase as root biomass increases, as is expected intuitively and as is seen in observations. Root biomass data from temperate coniferous, tropical evergreen, and tundra sites show that the approach successfully represents, to the first order, the change of root distribution and rooting depth as a function of root biomass.
منابع مشابه
Highlighting the Importance of the Vegetation Variable on Distributed Land surface temperature on different land use/land cover in Javanrud city range
In environmental models, Vegetations are considered as an important part in controlling environmental changes. To determine the importance of vegetation on land surface temperature (LST), preliminary preprocessing was performed on Landsat 8 image and a split window procedure was used to determine surface temperature. Temperature difference with the surrounding synoptic stations was estimated to...
متن کاملAssessment of the Efficiency of Climatic factors and geomorphometry in predicting vegetation percentages based on machine learning processes
Introduction: Rangelands are natural ecosystems having large genetic resources. Since plant vegetation is the bed of life on earth and changes under the influence of surrounding environmental elements, using environmental element can highly contribute to estimate vegetation percent more accurately. Two effective elements which can contribute to estimate the vegetation distribution are climatic ...
متن کاملPotentials of Evolving Linear Models in Tracking Control Design for Nonlinear Variable Structure Systems
Evolving models have found applications in many real world systems. In this paper, potentials of the Evolving Linear Models (ELMs) in tracking control design for nonlinear variable structure systems are introduced. At first, an ELM is introduced as a dynamic single input, single output (SISO) linear model whose parameters as well as dynamic orders of input and output signals can change through ...
متن کاملBayesian Quantile Regression with Adaptive Lasso Penalty for Dynamic Panel Data
Dynamic panel data models include the important part of medicine, social and economic studies. Existence of the lagged dependent variable as an explanatory variable is a sensible trait of these models. The estimation problem of these models arises from the correlation between the lagged depended variable and the current disturbance. Recently, quantile regression to analyze dynamic pa...
متن کاملارزیابی مدلهای تعرق و جذب آب درخت زیتون با استفاده از لایسیمتر
Different root water uptake models have recently been used. In this article, we use evapotranspiration data and soil water content data obtained from lysimeter measurements and root distribution in soil data obtained from olive tree to evaluate the accuracy of root water uptake models in predicting the soil water content profiles. Depth of lysimeter was 120 cm which was filled with clay-loam. L...
متن کامل