Publicações

The aerosol and trace gas three dimensional variational data assimilation system (3D-VAR) of CCATT-BRAMS, the Coupled Chemistry-Aerosol-Tracer Transport model coupled to the Brazilian developments on the Regional Atmospheric Modeling System (BRAMS) will be presented. In the framework of a case study over South America during the fire season in October 2007, Aerosol Optical Depth (AOD) columns from the Moderate Resolution Imaging Spectroradiometer (MODIS), and from ground based AERosol Robotic NETwork (AERONET) sites were assimilated. Simulation improvements by adding observational information are discussed. In particular, we will address the improvement achieved by introducing inhomogeneous and anisotropic areas of influence to enhance the impact and representativeness of valuable though sparsely distributed AERONET observations.

Emission data is an important source of uncertainties in chemical weather forecast. In particular, when only global inventories, or any inventory that doesnt consider the specifics of local data, is used. An improved emission inventory was included into the CCATT-BRAMS emission preprocessor, including reactive organic compounds (ROC) speciation and local information for Cuba. Emissions processed with the preprocessor for a 20 km grid for Cuba, obtained with global inventory EDGAR 32FT2000 with and without improvement, are presented, including results representative of speciation for chemical mechanisms RACM and RELACS.

This study aimed at evaluating the response of the Normalized Difference Vegetation Index – NDVI (MODIS sensor, TERRA satellite) of soybean to interannual variability of rainfall and evapotranspiration in Campos Gerais, a region of the state of Parana in southern Brazil. Landsat TM 5 and 7 images were selected for analyzing the spatial soybean field distribution for the region from 2000/01 to 2006/07 and to identify soybean fields. We then identified 175 pixels (250 x 250m) that contained only soybean fields (pure-pixels) based on the soybean maps obtained with the Landsat TM images. The next step was to extract the NDVI values for these soybean pure-pixels and to analyze the NDVI spectral curves considering the soybean phenology. Data from nearby meteorological stations were obtained and used to calculate the soil water balance for soybean fields in 5 locations distributed in the Campos Gerais region. To obtain actual evapotranspiration values, the water balance was calculated for each year, and for the same period covering the entire soybean growing season. Anomaly values were calculated for each year to verify the interannual rainfall variability. Linear regression models were adjusted between NDVI and i) rainfall and ii) actual evapotranspiration for all time series. Analysis of the evolution of NDVI values allowed identifying the soybean growing season (November to March) and also the dry season for this region according to rainfall anomaly values. Statistical analyses showed that actual evapotranspiration presented best agreement with soybean NDVI in relation to rainfall, probably due to the fact that this variable integrates information of rainfall, temperature and soil water holding capacity for the entire study period.

Although sugarcane crop is admittedly relevant to Brazilian economy, the increase of ethanol demand may produce significant environmental impacts. The common practice of pre-harvest burning of sugarcane straw emits particulate material, greenhouse gases, and tropospheric ozone precursors to the atmosphere. Although there are policies to eliminate this burning practice in Brazil until 2020, the effectiveness of this regulation is still questionable and the environmental damages during this period may be significant. Thus the generation of reliable inventories of emissions due to this activity is crucial in order to assess the environmental impact. In this context, this work is a first exercise to determine sugar cane straw burning emission factors in laboratory for some trace gases and quantify total emissions associated with pre-harvest sugarcane burning practice in São Paulo State . Excess mixing ratios for CO2, CO, NOX, and UHC (unburned hydrocarbons) were measured, allowing the estimation of their respective emission factors. Average values for emission factors estimated (g kg -1 of burned dry biomass) were: 1303 ± 218 for CO2, 65 ± 14 for CO, 1.5 ± 0.4 for NOx, and 16 ± 6 for UHC. The relative amount of sugar cane straw burning was also observed in flaming and smoldering combustion steps.

This document aims to present: (1) an analysis of distinct geospatial data dynamics and real application demands on representing and querying spatio-temporal data; and (2) a critical review of ten spatio-temporal database models proposed in the literature during the past two decades. This is an initial part of an ongoing work whose objective is to define a new database model, called Dynamic Geospatial Database Model (DyGeo Model), able to represent and query different geospatial data dynamics and so to support different kinds of spatio-temporal applications.

Strong interactions between soil moisture and the atmospheric processes take place in all spatial and temporal scales. The effects of soil moisture on rainfall can be associated with dynamical modifications of atmospheric systems as well as the generation of mesoscale circulations through the formation of spatial sensible heat flux gradients. A new effort towards a more realistic representation of soil moisture and its impact on the modeling of weather systems is presented. The Eta model is chosen to perform numerical simulations over South America testing the sensitivity of precipitation to soil and soil moisture changes. In this sense, the meteorological situation analyzed is a cold front crossing southeastern South America which is followed by the development of a mesoscale convective complex over northern Argentina in October 2006. The ETA model was configured to run on a 40km grid resolution and 38 vertical levels on a domain which includes all of South America north of 40°S. Initial conditions used to force the Eta Model experiments are taken from the CPTEC global model (Bonatti 1996), as well as the lateral boundary conditions which are updated every 6 hours. The control run (CTRL) uses the NOAH land surface model, with a 4 layer soil model and 9 different types of soil. Three other experiments were performed in order to test the sensibility to modifications of a) initial soil moisture conditions (MOIST), b) a new soil map (MAP) and c) both initial soil mositure conditions and new soil map (M&M). Modified initial soil moisture conditions for the ETA simulations were obtained from a hydrological balance model developed and running operational at CPTEC. The model uses integrated daily precipitation obtained from TRMM product 3B42 version 6 on a 0.25° x 0.25° grid, and rain gauge observed precipitation collected by different institutions in Brazil and by the National Weather Services of Argentina, Uruguay and Paraguay. A new soil map was elaborated using the available soil profile information in the CPTEC/INPE soil data base. It includes information on soil profiles for Brazil, Paraguay, Uruguay and Argentina. Each profile includes basic information such as soil types, texture classes, horizon depths, amount of organic carbon, etc. The different hydrological parameters defining each soil were obtained applying pedotransfer functions. The new soil map includes 16 different soil types. Results indicate that modifying inicial soil moisture conditions and incorporating a new soil map with hydraulic parameters, more representative of South American soils, improves rainfall forecasting both through a better spatial representation of precipitation and a daily total precipitation values. Although both CTRL and M&M overestimate the total precipitation of the MCC, M&M maximum precipitation is located closer to Presidente Roque Saenz Peña where the most intense precipitation was registered and the difference with the observed value is smaller.