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The interplay between atmosphere, hydrology and land use by environmental modelling

Pereira, Fabio LU (2013)
Abstract
Interactions between land surface and atmosphere induced by human activities and natural environmental dynamics act on a time scale that varies from seconds to millions of years. It is by exchanging heat, water, energy and carbon that land surface and atmospheric processes are closely interrelated and influence each other in reciprocal ways. Among the natural interactions between land surface and
atmosphere, the water cycle stands out for its complexity and relevance to all other physical processes.

In this context, numerical models are largely recommended as tools capable of quantifying, predicting and assessing the soil, surface and atmospheric water budgets. Atmospheric models present a detailed and complex approach to atmospheric... (More)
Interactions between land surface and atmosphere induced by human activities and natural environmental dynamics act on a time scale that varies from seconds to millions of years. It is by exchanging heat, water, energy and carbon that land surface and atmospheric processes are closely interrelated and influence each other in reciprocal ways. Among the natural interactions between land surface and
atmosphere, the water cycle stands out for its complexity and relevance to all other physical processes.

In this context, numerical models are largely recommended as tools capable of quantifying, predicting and assessing the soil, surface and atmospheric water budgets. Atmospheric models present a detailed and complex approach to atmospheric processes that includes estimation of carbon, heat, energy and water fluxes between surface and atmosphere based on energy, mass and momentum equations. The numerical solution of these equations include effects of sub-grid
scale processes that are not resolved by numerical schemes but affect the resolved scales. These unresolved processes are described in terms of semi-empirical relationships by means of parameterizations.

Despite widely acknowledged improvements in parameterizations of vegetation and soil processes in order to interpret the complexities inherent in the water cycle and its interactions with the atmosphere, parameterization schemes usually apply prescribed values of parameters based on their probability density functions which assume vegetation and soil characteristics as continuous distributions, consequently, mixtures in soil and vegetation within an area of interest are not captured. Therefore, the research described in this thesis
aimed at understanding the interplay between hydrology and the atmosphere under land use changes using a two-way coupled model that incorporates a process-based approach to land surface hydrological processes to resolve both surface features and the full atmospheric response to them.

A rapid expansion of the plantation of sugarcane over the Rio Grande basin, Brazil, as a response to government measures to boost ethanol production was used as a case study on this thesis. To reproduce the sugarcane expansion over the Rio Grande basin, historical land use scenarios were defined based on satellite images captured n 1993, 2000 and 2007. Further, a forth land use scenario was also generated based on the mapping of areas suitable for cultivation of sugarcane made by the Brazilian Institute for Agricultural Research - EMBRAPA. Thereafter, specific model parameters for sugarcane were
calibrated and validated to perform analysis of short-, medium- and long-term impacts of sugarcane expansion on the local hydrology. In the meanwhile, an atmospheric-hydrological modelling system was implemented and tested against estimates from a well-known atmospheric model, satellite imagery and observed data.

Results obtained from numerical and imagery analysis revealed that most of the sugarcane expansion occurred over areas close to the outlet of the Rio Grande basin where climate and topographical conditions are more attractive for growing sugarcane. They also indicated that the amount of areas replaced with sugarcane plantations, their location within the basin, regional soil properties, and local groundwater contribution to stream flow are the main factors related to the impacts of sugarcane expansion on the water balance of the Rio Grande basin. Additionally, numerical analyses carried out in this thesis showed that the replacement of land surface parameterizations by process-based hydrological modelling implied improvement in temperature, atmospheric water content and zonal and meridional winds calculated near land surface. Finally, a conceptual evaluation of the interplay of land use changes, hydrology and atmosphere as given by the hybrid coupled model was carried out. The main goal of this evaluation was to assess whether the model behavior is in accordance with improved understanding of the hydrological cycle of the Rio Grande basin under land use changes due to sugarcane expansion over its drainage area, resulting in this work. The results obtained from four model runs using historic and possible land use scenarios showed that exchange of water between soil, land surface and atmosphere is an important factor that determines which processes will dominate the water balance during wet and dry seasons under expansion of agricultural lands. (Less)
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author
supervisor
oppenent
  • Fernando Mirales-Wilhelm, University of Maryland, USA
organization
year
type
Dissertation (Composite)
subject
keywords
Land use changes, expansion of sugarcane, hydrological cycle, coupled models
pages
211 pages
publisher
Media-Tryck
defense location
Lecture hall V:B, V-building, John Ericssons väg 1, Lund University Faculty of Engineering
defense date
2013-12-20 10:15
ISSN
9789174737769
language
English
LU publication?
yes
id
4178378
date added to LUP
2013-11-29 12:16:35
date last changed
2013-11-29 12:16:35
@phdthesis{4178378,
  abstract     = {Interactions between land surface and atmosphere induced by human activities and natural environmental dynamics act on a time scale that varies from seconds to millions of years. It is by exchanging heat, water, energy and carbon that land surface and atmospheric processes are closely interrelated and influence each other in reciprocal ways. Among the natural interactions between land surface and
atmosphere, the water cycle stands out for its complexity and relevance to all other physical processes.

In this context, numerical models are largely recommended as tools capable of quantifying, predicting and assessing the soil, surface and atmospheric water budgets. Atmospheric models present a detailed and complex approach to atmospheric processes that includes estimation of carbon, heat, energy and water fluxes between surface and atmosphere based on energy, mass and momentum equations. The numerical solution of these equations include effects of sub-grid
scale processes that are not resolved by numerical schemes but affect the resolved scales. These unresolved processes are described in terms of semi-empirical relationships by means of parameterizations.

Despite widely acknowledged improvements in parameterizations of vegetation and soil processes in order to interpret the complexities inherent in the water cycle and its interactions with the atmosphere, parameterization schemes usually apply prescribed values of parameters based on their probability density functions which assume vegetation and soil characteristics as continuous distributions, consequently, mixtures in soil and vegetation within an area of interest are not captured. Therefore, the research described in this thesis
aimed at understanding the interplay between hydrology and the atmosphere under land use changes using a two-way coupled model that incorporates a process-based approach to land surface hydrological processes to resolve both surface features and the full atmospheric response to them.

A rapid expansion of the plantation of sugarcane over the Rio Grande basin, Brazil, as a response to government measures to boost ethanol production was used as a case study on this thesis. To reproduce the sugarcane expansion over the Rio Grande basin, historical land use scenarios were defined based on satellite images captured n 1993, 2000 and 2007. Further, a forth land use scenario was also generated based on the mapping of areas suitable for cultivation of sugarcane made by the Brazilian Institute for Agricultural Research - EMBRAPA. Thereafter, specific model parameters for sugarcane were
calibrated and validated to perform analysis of short-, medium- and long-term impacts of sugarcane expansion on the local hydrology. In the meanwhile, an atmospheric-hydrological modelling system was implemented and tested against estimates from a well-known atmospheric model, satellite imagery and observed data.

Results obtained from numerical and imagery analysis revealed that most of the sugarcane expansion occurred over areas close to the outlet of the Rio Grande basin where climate and topographical conditions are more attractive for growing sugarcane. They also indicated that the amount of areas replaced with sugarcane plantations, their location within the basin, regional soil properties, and local groundwater contribution to stream flow are the main factors related to the impacts of sugarcane expansion on the water balance of the Rio Grande basin. Additionally, numerical analyses carried out in this thesis showed that the replacement of land surface parameterizations by process-based hydrological modelling implied improvement in temperature, atmospheric water content and zonal and meridional winds calculated near land surface. Finally, a conceptual evaluation of the interplay of land use changes, hydrology and atmosphere as given by the hybrid coupled model was carried out. The main goal of this evaluation was to assess whether the model behavior is in accordance with improved understanding of the hydrological cycle of the Rio Grande basin under land use changes due to sugarcane expansion over its drainage area, resulting in this work. The results obtained from four model runs using historic and possible land use scenarios showed that exchange of water between soil, land surface and atmosphere is an important factor that determines which processes will dominate the water balance during wet and dry seasons under expansion of agricultural lands.},
  author       = {Pereira, Fabio},
  issn         = {9789174737769},
  keyword      = {Land use changes,expansion of sugarcane,hydrological cycle,coupled models},
  language     = {eng},
  pages        = {211},
  publisher    = {Media-Tryck},
  school       = {Lund University},
  title        = {The interplay between atmosphere, hydrology and land use by environmental modelling},
  year         = {2013},
}