Humberto R. Rocha

The effects of biomass burning aerosols and clouds on the CO2 flux in Amazonia

Aerosol particles associated with biomass burning emissions affect the surface radiative budget and net ecosystem exchange (NEE) over large areas in Amazonia during the dry season. We analysed CO2 fluxes as a function of aerosol loading for two forest sites in Amazonia as part of the LBA experiment. Aerosol optical thickness (AOT) measurements were made with AERONET sun photometers, and CO2 flux measurements were determined by eddy-correlation. The enhancement of the NEE varied with different aerosol loading, as well as cloud cover, solar elevation angles and other parameters. The AOT value with the strongest effect on the NEE in the FLONA-Tapajós site was 1.7, with an enhancement of the NEE of 11% compared with clear-sky conditions. In the RBJ site, the strongest effect was for AOT of 1.6 with an enhancement of 18% in the NEE. For values of AOT lager than 2.7, strong reduction on the NEE was observed due to the reduction in the total solar radiation. The enhancement in the NEE is attributed to the increase of diffuse versus direct solar radiation. Due to the fact that aerosols from biomass burning are present in most tropical areas, its effects on the global carbon budget could also be significant.

Water use in a sugarcane plantation

The evapotranspiration (E) from a sugarcane plantation in the southeast Brazil was measured by the eddy‐covariance method during two consecutive cycles. These represented the second (393 days) and third year (374 days) re‐growth (ratoon). The total E in the first cycle was 829 mm, accounting for 69% of rainfall, whereas in the second cycle, it was 690 mm, despite the total rainfall (1353 mm) being 13% greater. The ratio of E to available energy, the evaporative fraction, exhibited a smaller variation between the first and second cycles: 0.58 and 0.51, respectively. The estimated interception losses were 88 and 90 mm, respectively, accounting for approximately 7% of the total rainfall. The sugarcane yield in the second cycle (61.5 ± 4.0 t ha−1) was 26% lower than the first cycle, as well as lower than the regional average for the third ratoon (76 t ha−1). The below average yield was associated with less available soil water at the beginning of the cycle, with the amount of rainfall recorded during the first 120 days of re‐growth in the second cycle being 16% of that recorded in the first (203 mm).

SENSIBILITY OF DISTRIBUITED BIOSPHERE-HYDROLOGICAL MODEL TO HYDRAULIC SOIL PROPERTIES FOR A SMALL BASIN OF WOODLAND SAVANNA

For modeling of hydrologic processes that occur on the scale of watersheds to characterize the availability of water in it, you need a physical model that can represents the topography, vegetation and soil characteristics. On the other hand, the variables that provide atmospheric forcing require great accuracy and models are sensitive to them mainly to rainfall, it is the main input in hydrological modeling. This study focuses on evaluation of four physical parameters of soil in hydrologic modeling in Giant Foot basin, SP, Brazil with DBHM model. The study period covers the years 2009-2014, FAO’s soil maps were used for the physical characterization of the basin, and the MODIS for vegetation data (LAI and FPAR). Domain of 500 m for spatial resolution in a basin area of 11.94 km2. Was used a basic configuration that let determine the influence of soil parameters in the water content results for the surface layer up to 1 m. It shows higher water retention in the soil to high values of the Campbell parameter, matric potential and porosity; sensitivity to hydraulic conductivity depends on the relationship with the daily accumulated rainfall.

Fluxos de CO2 para cenários de aquecimento em área de floresta através de simulações do modelo SIB2

Fluxos de CO2 para cenarios de aquecimento em area defloresta atraves de simulacoes do modelo SIB2

ANÁLISE DOS ESQUEMAS DE SUPERFÍCIE DO MODELO WRF: UM ESTUDO DE CASO PARA A FLORESTA TROPICAL AMAZÔNICA

O trabalho teve como objetivo testar os diferentes esquemas desuperficie acoplados ao modelo Weather Research and Forecasting (WRF)para uma area de floresta tropical na Amazonia. Os esquemas de superficietestados foram: Noah-LSM, RUC-LSM e o esquema de difusao termica,para o dia 02 de fevereiro de 2008 durante a estacao chuvosa. Osfluxos de energia simulados foram comparados com as observacoes deuma torre de fluxo instalada na regiao. Os resultados preliminares indicaramque o esquema Noah-LSM foi o que melhor representou a particaodos fluxos de energia (H e LE) para aquela regiao.

COMPARAÇÃO DA RADIAÇÃO SOLAR GLOBAL INCIDENTE OBTIDA POR DIFERENTES FONTES DE DADOS PARA O NORTE DE SP

O objetivo deste trabalho foi comparar os dados de radiacaosolar global incidente de tres torres micrometeorologicas localizados naregiao norte do estado de Sao Paulo, com os dados disponiveis de outrasfontes: estacoes meteorologicas de superficie mais proximas e estimativasa partir de satelites (modelo GL1.2). A regressao linear entre as estimativasde radiacao do modelo GL1.2 com as observacoes na area decerrado indicou um ajuste melhor do que o obtido com a estacaometeorologica mais proxima. Esses resultados sugerem que as estimativasde radiacao do modelo GL1.2 podem ser usadas para o preenchimentode falhas de Ki medida nas torres micrometeorologicas e potencialmentecomo forcante em esquemas de superficie e modelos hidrologicosaplicados a bacias hidrograficas da regiao.

VARIABILIDADE DAS MEDIDAS DE FLUXOS DE CO2 DO SOLO OBTIDAS PELO MÉTODO DA CORRELAÇÃO DE VÓRTICES

Variabilidade das medidas de fluxos de CO2 do solo obtidaspelo metodo da correlacao de vortices

AVALIAÇÃO DO MÉTODO DE MULTIPLE IMPUTATION NO PREENCHIMENTO DE FALHAS DE FLUXOS DE ENERGIA SOBRE UMA ÁREA DE CANA-DE-AÇÚCAR

Avaliacao do metodo de Multiple Imputation nopreenchimento de falhas de fluxos de energia sobre umaarea de cana-de-acucar

FLUXOS DE SUPERFÍCIE EM TOPOGRAFIA COMPLEXA

1. Introducao A aplicacao da covariância de vortices em areas de vegetacao natural tem possibilitado o monitoramento das interacoes superficie-atmosfera, alem da maior integracao espacial (Baldochi et al., 2000). Entretanto, as areas remanescentes no sudeste do Brasil sao espacialmente heterogeneas e de topografia irregular, que restringem as suposicoes da existencia da camada de fluxo constante devido a separacao do escoamento (Finnigan& Belcher, 2004) e problemas relativos a adveccao (Staebler & Fitzjarrald,2004).