@MastersThesis{Chaves:1992:PeEsBa,
author = "Chaves, Marcelo de {\'A}vila",
title = "Perspectivas de estimativa dos balan{\c{c}}os anuais
h{\'{\i}}drico e de carbono em ecossistemas florestais {\`a}
partir de um modelo biogeoqu{\'{\i}}mico florestal associado a
t{\'e}cnicas de sensoriamento remoto orbital",
school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
year = "1992",
address = "Sao Jose dos Campos",
month = "1992-07-09",
keywords = "vegeta{\c{c}}{\~a}o, ecossistemas, {\'{\i}}ndice de {\'a}rea
foliar, florestas, biogeoqu{\'{\i}}mica, modelos, carbono,
classifica{\c{c}}{\~a}o de imagens, biogeochemistry, carbon
cycle, conifers, ecosystems, environmental models, hydrological
cycle, leaf area index, rain forest, image classification,
vegetation, coniferas.",
abstract = "Este trabalho tem por objetivo testar e avaliar o potencial de
utiliza{\c{c}}{\~a}o de um modelo biogeoqu{\'{\i}}mico
regional para representar os principais processos do ciclo
hidrol{\'o}gico e do carbono de ecossistemas florestais de
con{\'{\i}}feras, existentes em tr{\^e}s estados brasileiros,
submetidos a condi{\c{c}}{\~o}es ambientais contrastes. Este
modelo, denominado Forecos, tem como principal vari{\'a}vel de
entrada o {\'{\i}}ndice de {\'a}rea foliar (IAF) que e um dos
par{\^a}metros mais importantes na qualifica{\c{c}}{\~a}o de
trocas de energia e massa de ecossistemas florestais. O IAF pode
ser estimado por sensores remotos orbitais, pois e a vari{\'a}vel
estrutural da vegeta{\c{c}}{\~a}o mais correlacionada com os
{\'{\i}}ndices de vegeta{\c{c}}{\~a}o que s{\~a}o obtidos a
partir de dados espectrais de imagens de sat{\'e}lites. Assim
sendo, realizou-se o teste de sensibilidade das vari{\'a}veis do
modelo e a simula{\c{c}}{\~a}o dos valores de IAF. Realizou-se
tamb{\'e}m a classifica{\c{c}}{\~a}o digital de imagens
{\'{\i}}ndice de vegeta{\c{c}}{\~a}o com o objetivo de obter
padr{\~o}es de mapeamento desses {\'{\i}}ndices que devem
refletir varia{\c{c}}{\~o}es nos valores de IAF embora valores
absolutos n{\~a}o possam ser estimados nesta etapa do trabalho.
Os resultados obtidos demonstram que o modelo, quando rodado de
uma maneira geral, foi capaz de retratar diferen{\c{c}}as
relativas entre os processos b{\'a}sicos dos ciclos
hidrol{\'o}gicos e do carbono. O modelo conseguiu tamb{\'e}m
descrever quantitativamente as intera{\c{c}}{\~o}es entre os
fatores ambientais de cada {\'a}rea teste com os processos
f{\'{\i}}sicos e biol{\'o}gicos que ocorreram nos ecossistemas
florestais selecionados. Entretanto, a modelagem de alguns
processos necessita ser revista ou ajustada e a
valida{\c{c}}{\~a}o final do modelo requer medidas especificas
de alguns par{\^a}metros e condi{\c{c}}{\~o}es iniciais. Os
resultados obtidos nas classifica{\c{c}}{\~o}es de imagens
digitais sugerem uma homogeneidade nos valores de IAF para as
{\'a}reas teste o que, de certa forma, valida a
utiliza{\c{c}}{\~a}o de um {\'u}nico valor de IAF na
simula{\c{c}}{\~a}o realizada. ABSTRACT: This work is intended
to test and to evaluate how well a regional biogeochemical model
is able to represent the major processes of the hydrologic and
carbon cycles of forest ecosystems of coniferous, growing up in
three different climatic areas in Brazil. The model, named
{"}Forecos{"} uses Leaf Area Index, LAI, as the main input
variable. LAI is generally accepted as being the most import
variable characterizing the exchange of energy and mass in forest
ecosystems. There is substantial work done showing that LAI can be
estimated from remotely sensed data, on the basis of the
correlation that exists between this vegetation structure
parameter and vegetation index, obtained by manipulation of data
in different spectral bands of optical sensors. Simulations of LAI
of the real world and sensitivity analysis on some critical
parameters were used to test the suitability of the model to
represent the processes modeled. By the means of digitat image
classification, patterns of vegetation indexes were identified
that should correspond to variations on LAI values, although
absolute numbers could not be obtained at this step. The results
have demonstrated that the model was able to show the relative
differences for both hydrologic and carbon cycles for the three
test sites studied. Besides that, the model was also capable of
describing quantitatively the interactions between climatic
parameters and biophysical processes in the ecosystems selected.
Nevertheless, the mathematical formulation of some processes has
to be revised or adjusted through fitting techniques. Finally a
validation should be achieved with measurements of state variables
and some independent measurements of net primary production and
hydrologic variables. The results obtained from digital
classification suggest that LAI values are homogeneous in all test
sites. Then, the use of a unique regional value within the
simulations realized is felt to be valid.",
committee = "Soares, Jo{\~a}o Vianei (orientador/presidente) and Nobre, Carlos
Afonso and Batista, Get{\'u}lio Teixeira and Vict{\'o}ria,
Reynaldo Luiz",
copyholder = "SID/SCD",
englishtitle = "On the computation of carbon and water cycles in forest ecosystems
using a biogeochemical model and remotely sensed data",
label = "3189",
language = "pt",
pages = "166",
ibi = "6qtX3pFwXQZ3r59YD6/GP2Ds",
url = "http://urlib.net/ibi/6qtX3pFwXQZ3r59YD6/GP2Ds",
urlaccessdate = "02 maio 2024"
}