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PC-02 Abstract

Surface Radiation Budgets for LBA

Juan Carlos Ceballos — CPTEC - Centro de Previsão do Tempo e Estudos Climáticos (INPE) (SA-PI)
Rachel T Pinker — University of Maryland (US-PI)

The objectives of our participation in LBA-Hydrometeorology are:


Provide information on radiative fluxes that is required for advancing

the understanding of the role of water in land-atmosphere interactions;

this will include the total shortwave radiative fluxes, as well as Photosynthetically

Active Radiation ( PAR) and Near-Infra-Red (NIR) radiation. This information

will be provided at both boundaries of the atmosphere, namely, at the top

of the atmosphere and at the earth's surface. 

Develop improved techniques for providing such information, that take into

account deforestation and biomass burning in the Amazon Basin. Availability

of shortwave radiative fluxes at both boundaries of the atmosphere will

allow estimation of the contribution of smoke to the solar heating of

the atmospheric column.

Initially, we will provide historical information on surface and top

of the atmosphere radiative fluxes, both on global and regional scales,

to help the modeling community synthesize their current hydrological models and improve their capabilities to test scientific issues of concern

to the hydrology component of LBA. Historical radiative fluxes will be

produced as part of an ongoing EOS

activity. Under the current project, they will be prepared

to meet the needs of the LBA investigators.

New activities will be initiated to 1) improve existing capabilities to

derive surface and top of the atmosphere radiative fluxes by incorporating

unique conditions that exist over the Amazon Basin, particularly in respect

to deforestation and biomass burning; and 2) implement these improved methodologies

at spatial and temporal scales of interest to the hydrological and ecological

modeling community. This aspect of our activity will be directly related

to activities anticipated during the LBA experiment, and will utilize

results from the Ecology module of the LBA Project.

Specifically, we plan to improve the characterization of surface conditions

in the radiative retrieval scheme.  We will account for effects of deforestation,

and also include better detection of smoke from biomass burning and thus more

accurate modeling

in terms of its aerosol effects. "Ground truth" on surface radiative fluxes

will be collected by independent investigators and used to test our algorithm

in this unique environment, where high quality ground truth is almost non-existent.  

In the context of the list of LBA-Hydrometeorology research priorities,

the information that will result from this project will lead to consideration of

the following issues:


Priority topic 1: Global scale hydrometeorology



Evaluation of land surface

parameterization and the implications for global

climate and weather forecast models


Priority topic 2: Continental and regional scale hydrometeorology


Estimation of the surface hydrological and energy budgets at regional and

continental scales 


Modeling and prediction of the surface hydrological and energy budgets

of the LBA region on time scales from diurnal to interannual


Development and testing of improved algorithms to predict surface radiation

budgets that take into account deforestation in Rondonia and information

on biomass burning in the Amazon Basin


Documentation of regional and continental energy and water cycles within

the LBA Project


Priority topic 3: Mesoscale hydrometeorology


Enhancement of

the understanding of mesoscale convective and/or land surface




topic 4
: Regional and continental scale surface hydrology


Demonstration of the use of remotely sensed hydrometeorological variables

in connection with models of land surface fluxes.

An example on the distribution of monthly mean surface shortwave radiative

fluxes for four mid-season months during 1992 are illustrated in Figure

1. They are given at a resolution of 0.5 degree, and are available at 3-hourly

intervals, on daily time scales. The area covered was selected to include

all the various basins, as illustrated in Figure 2 below.

Note: Feedback is requested from LBA investigators as to the

spatial coverage needed for their studies that require information on radiative


Figure 1.

Figure 2.

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