A Decade of Progress in Modeling the Hydroclimatology

of the Amazon System

Marcos Heil Costa

Universidade Federal de Viçosa

III LBA Scientific Conference

Brasília – July 2004

Overview

• Review studies on large-scale hydrological modeling

• Review studies on climate modeling, including the biosphere-atmosphere interaction

• Future trends

Large-Scale Hydrological Systems

• 1994:

– A few basin/continental-scale routing-scheme-based large-scale hydrological studies performed

– Mainly water transport models

– Basic flooding scheme

Large-Scale Hydrological Systems

• Since 1994:– Increased model resolution– New input and validation products

• New remote sensing products

• Basin-wide water chemistry measurements (HIBAM)

– Improved validation (many discharge stations, water height, flooded area)

– Focus on land use/land cover change

Large-Scale Hydrological Systems

• Current research efforts

– New validation efforts, specially with respect to flooded area, soil moisture

– Water chemistry (carbon)

Tapley et al. (2004) – Geoid height estimates from the GRACE mission

Large-Scale Hydrological Systems

• Future research efforts

– Not much room for large-scale water balance/ water transport simulations – just refinements

– Plenty of room for large-scale hydrochemical/ water quality studies

Climate System

• 1994:

– Several climate studies demonstrating the role of local vegetation on the local climate

– ABRACOS field observations completed, but climate experiments did not benefit from such measurements yet

Climate System• Since 1994:

– Post-ABRACOS studies indicate climate change after a deforestation may not be as strong as initially thought

Post-ABRACOS

studies

ABRACOS recommendation

Climate System• Since 1994:

– Combined effects of deforestation and rising CO2

– Dynamic/equilibrium vegetation studies for present climate, LGM and 2xCO2 scenarios

– Role of Amazonia in the global carbon cycle

– Debate between regional- and global-scale modellers

– Evidence that

• small-scale deforestation would lead to increasing precipitation

• large-scale deforestation would lead to decreasing precipitation

Climate System

• Current research efforts:

– Search for confirmation/ explanation of the small/large-scale dichotomy

– Focus on current levels of deforestation/ near future (~10-40 years) scenarios

Climate System

• Future research efforts:

– Will we be able to forecast the 2010-2050 Amazon climate?

– Or are we still studying scenarios?

Climate System• Future research efforts:

– At the multi-decadal time scales, we must consider:

• interdecadal variability of climate (NAO, PDO)

• rising CO2

• effects of deforestation

– In the 10-40 years scale, the interdecadal variability of climate may be stronger than the effects of partial deforestation, which may be stronger than the effects of rising CO2

– for multi-decadal climate forecasts, we should include modes of climate variability that depend on the ocean

Thank you!