Marcio Moraes Sep 2010 Hydrology and Regional Modeling Marcio Moraes and Cintia Bertacchi Lund...

Marcio Moraes Sep 2010Marcio Moraes Sep 2010

Hydrology and RegionalModeling

Marcio Moraes and Cintia BertacchiLund University

Water Resources Engineering


Project Subject• Impact of changes in the biosphere to local climate and

hydrology - How biofuel plantations affect local atmospheric circulation and rivers– The major scientific objective of this proposal is to create a model

system able to simulate the effects caused by the biosphere on the local/regional atmosphere and hydrology.

– the final objective of the project is the assessment of the impacts of the expansion of the plantation of biofuel species, in substitution to the native vegetation or to the prior customary crops, to the local climate and hydrology


The aim of this project

• (1) adaptation and adjusting of a hydrological model to a characteristic river basin where sugar-cane plantation has been expanding significantly.

• (2) Analyse the capacity of a regional atmospheric model to simulate local climate in the same region as in (1).

• (3) Develop a two-way coupling of the atmospheric and hydrological models.

• (4) Carry out experiments designed to analyse the impacts of the change in vegetation on the river basin and how these impacts will, on their hand, affect the local climate and,

• (5) finally, significantly improve the knowledge, and hopefully be able to quantify the impacts of the biofuel plantation on the local hydrology and climate


The chosen Models

• Atmospheric– Brazilian Regional Atmospherical Model

System – BRAMS• Modified version of RAMS (Walko et al 2000)• Large use in the Brazilian Forcast Institute –

INPE/CPTEC

• Hydrological– Large Basin Model – Hydraulic Research

Institute (MGB-IPH)– Applied in various brazilian basins


MGB-IPH

• Divide th basin in cells or mini-basins,

about 10x10 Km.

• Daily time step or small one.

• Represents the variability in the cells.

• Developed to big basins, > 104 Km2


• Process in the model

– Evapotranspiration

– Water storage in the soil

– Drainage in the cells

– Rivers and dams flow

MGB-IPH


• Input data– Precipitation and flow– Temperature, pressure, solar radiation,

relative humidity and wind velocity– Satelite images– Soil types– Digital Elevation Model– Transversal section of the rivers

MGB-IPH


BRAMS

• Braziliam Regional Atmospheric Model System – BRAMS– Based on RAMS (Walko et al. 2000) – version 6– RAMS is a multipurpose, numerical prediction model

designed to simulate atmospheric circulations spanning from hemispheric scales down to large eddy simulations (LES) of the planetary boundary layer (Walko et al., 2000, www.atmet.com)

– The model is equipped with a multiple grid nesting scheme which allows the model equations to be solved simultaneously on any number of interacting computational meshes of differing spatial resolution


• The model has a complex set of packages to simulate processes such as radiative transfer, surface-air water, heat and momentum exchanges, turbulent planetary boundary layer transport, and cloud microphysics.

• The initial conditions can be defined from various observational data sets that can be combined and processed with a mesoscale isentropic data analysis package (Tremback, 1990).

• For the boundary conditions, the 4DDA schemes allow the atmospheric fields to be nudged towards the large-scale data. BRAMS features used in this system include an ensemble version of a deep and shallow cumulus scheme based on the mass flux approach (Grell and Devenyi, 2002) and soil moisture initialization data (Gevaerd and Freitas, 2006).

BRAMS


• parameterizations are used in the model:– The horizontal diffusion coefficients are based on the Smagorinsky (1963)

formulation. – The vertical diffusion is parameterized according to the Mellor and Yamada

(1974) scheme, which employs a prognostic of the turbulent kinetic energy. – The surface-atmosphere water, momentum and energy exchanges are

simulated by the Land Ecosystem Atmosphere Feedback model (LEAF-3), which represents the storage and vertical exchange of water and energy in multiple soil layers, including the effects of freezing and thawing soil, temporary surface water or snow cover, vegetation, and canopy air (Walko et al., 2000).

– The advection scheme is forward upstream of second-order (Tremback et al, (1987)).

– Bulk microphysics (Walko et al., 2000) – Convective cumulus scheme for deep and shallow convection based on

Grell and Devenyi (2002). – The 4D Data Assimilation (4DDA), a nudging type scheme in which the

model fields can be nudged toward assimilated observational data.

BRAMS


LEAF-3 vertical levels and patches

NZS = 3NZS = 3

NZG = 7NZG = 7

Canopy airCanopy air

VegetationVegetation

SnowcoverSnowcover

WaterWater

SoilSoilNPATCH=5: P1 P2 P3 P4 P5NPATCH=5: P1 P2 P3 P4 P5

SINGLE ATMOSPHERIC COLUMNSINGLE ATMOSPHERIC COLUMN


PATCH 1PATCH 1 PATCH 2PATCH 2

LEAF–3LEAF–3

fluxesfluxes

wggwgg

wcawca hcahca

rvcrvchvchvc wvcwvc wvcwvc hvchvc

wgvc1wgvc1

AA wavwav

CC

VVVV

G2G2

G1G1

havhav

ravravCC

G2G2

S2S2

S1S1

rsarsahschscwscwsc

hcahca

hashaswaswas

wcawca

wsswss

wgswgs

wggwgg hgghgg

hgshgs

hsshss

rsvrsv

hvshvswvswvs

wgvc2wgvc2hgchgcwgcwgcrgarga

hgghgg

rgvrgv wgvc2wgvc2

wgvc1wgvc1G1G1

longwave longwave radiationradiation

sensible sensible heatheat

waterwater


Two way coupling of a conceptual hydrological Two way coupling of a conceptual hydrological

model to a regional atmospheric modelmodel to a regional atmospheric model

The Coupling processThe Coupling process

The region of study:The region of study:

•Rio Grande Basin: Brazil – South America


LEAF to hydrological scheme


Firts ResultsBRAMS MGB-BRAMS


BRAMS MGB-BRAMS


Tusen Takk

Marcio Moraes Sep 2010 Hydrology and Regional Modeling Marcio Moraes and Cintia Bertacchi Lund...

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