Artigo

Seasonal variation in net carbon exchange and evapotranspiration in a Brazilian rain forest: A modelling analysis

Tropical rain forests account for a significant fraction of global net primary productivity, and are important latent energy (LE) sources, affecting extra-tropical atmospheric circulation. The influence of environmental factors on these fluxes has until recently been poorly understood, largely due t...

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Autor principal: Williams, Mathew
Outros Autores: Malhi, Yadvinder Singh, Nobre, Antônio Donato, Rastetter, Edward B., Grace, John, Pereira, Maria G.P.
Grau: Artigo
Idioma: English
Publicado em: Plant, Cell and Environment 2020
Assuntos:
Carbon Cycle
Environmental Factor
Evapotranspiration
Modeling
Rainforest
Brasil
Acesso em linha: https://repositorio.inpa.gov.br/handle/1/19272
id oai:repositorio:1-19272
recordtype dspace
spelling oai:repositorio:1-19272 Seasonal variation in net carbon exchange and evapotranspiration in a Brazilian rain forest: A modelling analysis Williams, Mathew Malhi, Yadvinder Singh Nobre, Antônio Donato Rastetter, Edward B. Grace, John Pereira, Maria G.P. Carbon Cycle Environmental Factor Evapotranspiration Modeling Rainforest Brasil Tropical rain forests account for a significant fraction of global net primary productivity, and are important latent energy (LE) sources, affecting extra-tropical atmospheric circulation. The influence of environmental factors on these fluxes has until recently been poorly understood, largely due to a paucity of data, but in recent years the amount of available data has been increased greatly by use of eddy covariance techniques. In this paper we examine the factors that control daily and seasonal carbon (C) and LE fluxes, by comparing a detailed model of the soil-plant-atmosphere continuum against a unique long-term data-set collected using eddy covariance at an undisturbed rain forest site north of Manaus, Brazil. Our initial application of the model was parametrized with simple measurements of canopy structure, and driven with local meteorological data. It made effective predictions of C and LE exchange during the wet season, but dry season predictions were overestimates in both cases. Sensitivity analyses indicated that the best explanation for this behaviour was a seasonal change in soil and root hydraulic resistances (R(b)). An optimization routine was then used to estimate the increase in R(b) during the dry season that would be required to explain the reduced dry season fluxes. The local soil, a clay latosol, is typical of much of Amazonia, having very low available water and low hydraulic conductivity. We conclude that an increase in soil-root hydraulic resistance in the dry season introduces a significant seasonal cycle to carbon and water fluxes from this tropical forest. Furthermore, our model structure appears to be an effective tool for regional and temporal scaling of C and LE fluxes, with primary data requirements being regional and temporal information on meteorology, leaf area index (LAB, foliar N, critical leaf water potentials, and plant and soil hydraulic characteristics. 2020-06-15T22:06:55Z 2020-06-15T22:06:55Z 1998 Artigo https://repositorio.inpa.gov.br/handle/1/19272 10.1046/j.1365-3040.1998.00339.x en Volume 21, Número 10, Pags. 953-968 Restrito Plant, Cell and Environment
institution Instituto Nacional de Pesquisas da Amazônia - Repositório Institucional
collection INPA-RI
language English
topic Carbon Cycle
Environmental Factor
Evapotranspiration
Modeling
Rainforest
Brasil
spellingShingle Carbon Cycle
Environmental Factor
Evapotranspiration
Modeling
Rainforest
Brasil
Williams, Mathew
Seasonal variation in net carbon exchange and evapotranspiration in a Brazilian rain forest: A modelling analysis
topic_facet Carbon Cycle
Environmental Factor
Evapotranspiration
Modeling
Rainforest
Brasil
description Tropical rain forests account for a significant fraction of global net primary productivity, and are important latent energy (LE) sources, affecting extra-tropical atmospheric circulation. The influence of environmental factors on these fluxes has until recently been poorly understood, largely due to a paucity of data, but in recent years the amount of available data has been increased greatly by use of eddy covariance techniques. In this paper we examine the factors that control daily and seasonal carbon (C) and LE fluxes, by comparing a detailed model of the soil-plant-atmosphere continuum against a unique long-term data-set collected using eddy covariance at an undisturbed rain forest site north of Manaus, Brazil. Our initial application of the model was parametrized with simple measurements of canopy structure, and driven with local meteorological data. It made effective predictions of C and LE exchange during the wet season, but dry season predictions were overestimates in both cases. Sensitivity analyses indicated that the best explanation for this behaviour was a seasonal change in soil and root hydraulic resistances (R(b)). An optimization routine was then used to estimate the increase in R(b) during the dry season that would be required to explain the reduced dry season fluxes. The local soil, a clay latosol, is typical of much of Amazonia, having very low available water and low hydraulic conductivity. We conclude that an increase in soil-root hydraulic resistance in the dry season introduces a significant seasonal cycle to carbon and water fluxes from this tropical forest. Furthermore, our model structure appears to be an effective tool for regional and temporal scaling of C and LE fluxes, with primary data requirements being regional and temporal information on meteorology, leaf area index (LAB, foliar N, critical leaf water potentials, and plant and soil hydraulic characteristics.
format Artigo
author Williams, Mathew
author2 Malhi, Yadvinder Singh
Nobre, Antônio Donato
Rastetter, Edward B.
Grace, John
Pereira, Maria G.P.
author2Str Malhi, Yadvinder Singh
Nobre, Antônio Donato
Rastetter, Edward B.
Grace, John
Pereira, Maria G.P.
title Seasonal variation in net carbon exchange and evapotranspiration in a Brazilian rain forest: A modelling analysis
title_short Seasonal variation in net carbon exchange and evapotranspiration in a Brazilian rain forest: A modelling analysis
title_full Seasonal variation in net carbon exchange and evapotranspiration in a Brazilian rain forest: A modelling analysis
title_fullStr Seasonal variation in net carbon exchange and evapotranspiration in a Brazilian rain forest: A modelling analysis
title_full_unstemmed Seasonal variation in net carbon exchange and evapotranspiration in a Brazilian rain forest: A modelling analysis
title_sort seasonal variation in net carbon exchange and evapotranspiration in a brazilian rain forest: a modelling analysis
publisher Plant, Cell and Environment
publishDate 2020
url https://repositorio.inpa.gov.br/handle/1/19272
_version_ 1787142977389330432
score 11.755432

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