Simone Erotildes Teleginski Ferraz

An objective criterion for determining the South Atlantic Convergence Zone

The South Atlantic Convergence Zone (SACZ) is the dominant summertime cloudiness feature of subtropical South America and the western South Atlantic Ocean, having a significant influence on the precipitation regime of southeastern Brazil. This paper proposes an objective criterion based mainly on precipitation, as this variable is easily obtained on general circulation models simulating past, present and future climate. Usually most SACZ studies use emerging long wave radiation as a precipitation proxy. This is enough to describe event position at first, but using precipitation would allow for better quantification, especially for climate studies, where precipitation is indispensable. An assessment was carried out to find out if classical DJF period is ideal for determining the SACZ for the present climate and future scenarios. In general the SACZ event detection criterion showed quite satisfactory results when event dates were previously known. When it was applied to future climate scenario it identified a number of events compatible with the present climate. The SACZ was well defined for both the simulated and observed precipitation data.

Adaptação e avaliação do modelo infocrop para simulação do rendimento de grãos da cultura do arroz irrigado

This study aimed to adapt and evaluate the InfoCrop model for simulating grain yield of irrigated rice in Santa Maria, state of Rio Grande do Sul, Brazil. The grain yield of irrigated rice was simulated considering three versions of the InfoCrop model with adaptations for local rice cultivars. Simulated yields were compared to the yields observed in the Santa Maria county surveyed by the Instituto Riograndense do Arroz (Institute of Rice of Rio Grande do Sul - IRGA) from 1996/97 to 2008/09, and to the yields of experiments conducted at the Universidade Federal de Santa Maria (Federal University of Santa Maria - UFSM) from 1998/1999 to 2005/2006. The InfoCrop model captured the interannual variability of the grain yield of irrigated rice for the Santa Maria county and the experiments conducted at UFSM. The root mean squared error of the simulation of grain yield using the Version 3 of the InfoCrop model (better performance), considering all data observed, was 0.850 Mg ha-1, with overestimation trend, which may have occurred because the model considers a situation of potential yield, which does not always occur in commercial farming.

VARIAÇÕES CLIMÁTICAS NA PRECIPITAÇÃO NO SUL DO BRASIL NO CLIMA PRESENTE E FUTURO

Climate and its changes have been showing great prominence lately. In this way, it is important to analyze the precipitation trends for the understanding of the potential impacts that changes in climate may result in the society. This paper presents an analysis of the precipitation trend in Rio Grande do Sul, for three sets of data, with a comparison of the observed precipitation data and simulated data by RegCM3 Regional Model, as well as an analysis of the trend in a future climate scenario. This analysis was performed using different statistical tests, which calculated the of precipitation trends for the observed precipitation data, for the RegCM3 model data for the same period, 1982-2006, and for the 2070 to 2086 future climate modeled data. Evaluating the percentage of dry and wet events obtained from the observed data (PREC_LA), it was found that the modes in the synoptic band contribute greatly to dry events than to wet events. Yet in the intraseasonal band there is more contribution to the wet than to the dry events. The analyzed modes in the interannual band contribute equally to dry and wet events. However, when we observed the events in the simulated data (PREC_RE), the model failed to reproduce the observed results.

Mudanças climáticas e seus efeitos no rendimento de arroz irrigado no Rio Grande do Sul

The objective of this work was to estimate the irrigated rice grain yield in the rice production regions of the state of Rio Grande do Sul, Brazil, in different sowing dates, in a future climatic scenario - the A1B scenario from the Intergovernmental Panel on Climate Change (IPCC) - and to determine possible changes in the current sowing calendar for irrigated rice in this scenario. The SimulArroz model was used, considering three maturity groups (early, middle, and late) and seven sowing dates (8/1, 9/1, 10/1, 11/1, 12/1, 1/1, and 1/2) for each year of the climatic scenario, in the six rice production regions of the state. Among the rice production regions, there is a variation in the effect of climate change on yield, in which the Fronteira Oeste region is less favored and the Zona Sul region more favored in the future scenario. The projected climate change has a positive effect on rice grain yield in the state of Rio Grande do Sul, Brazil, mainly at the end of the 21st century, when the sowing period may be anticipated.

ANALYSIS FOR PRECIPITATION CLIMATE PREDICTION ON SOUTH OF BRAZIL

An evaluation for the precipitation climatology for the Rio Grande do Sul state (Brazil) is performed. The BRAMS code is feeded with boundary conditions from the CPTEC-INPE global circulation model (GCM). The simulated precipitation for this region in Brazil presented a climate standard diferent from the observations. An spectral analysis on the wind was carried out to explain the desagreement.

Sensitivity of RegCM3 Simulated Precipitation over Southern Brazil with Different Boundary Conditions: ENSO Case

This paper investigates the capability of a regional climate model (RegCM3) to simulate the Southern Brazil rainfall during three periods: the El Nino (1982), the neutral intermediary phase (1985), and the La Nina (1988). Each integration has used three of different boundary conditions available: NCEP-NCAR Reanalysis (I and II) and ECMWF Reanalysis—ERA-40. The simulations were performed covering a South America domain and some descriptive statistics analyses have been applied, like arithmetic mean, median, standard deviation and Pearson’s correlation; and frequencies histogram over Southern Brazil. The main results show that the model satisfactorily reproduces the rainfall in this region during the El Nino, neutral, and La Nina events, indicating that the boundary conditions which were tested adequately describe this simulations type.

ACOMPANHAMENTO DA SAFRA 2012/2013 DE ARROZ IRRIGADO NO RIO GRANDE DO SUL POR MODELAGEM NUMÉRICA

O objetivo deste trabalho foi realizar o acompanhamento de safra de arroz irrigado durante o ano agricola 2012/2013 para o estado do Rio Grande do Sul. Para o acompanhamento de safra, foi utilizado o modelo SimulArroz. Foi utilizado o grupo de maturacao precoce de cultivares de arroz, com simulacoes nos niveis de tecnologia alto, medio e baixo. A media de produtividade observada foi de 7481,7 kg/ha, enquanto que a media de produtividade simulada com o SimulArroz nos niveis de tecnologia alto, media e baixo foi de 8732,0 kg/ha, 7041,7 kg/ha e 5597,9 kg/ha respectivamente. O modelo demonstrou boa sensibilidade as variacoes meteorologicas entre as regioes do RS, demonstrando maior potencial produtivo de arroz para as regioes da Fronteira Oeste e da Campanha. Portanto, o modelo SimulArroz simulou de forma satisfatoria a produtividade de arroz irrigado para os municipios em que foi testado, podendo ser utilizado no acompanhamento de safra.

Rossby wave propagation during winters of maximum frequency of frost occurrence over the wet pampa

Neste trabalho estudou-se a influencia dos padroes de onda extratropicais, que favorecem o desenvolvimento de eventos extremos frios no sudeste Sul-Americano, e em particular na regiao conhecida como Pampa Umida. O aquecimento anomalo observado na regiao do oceano Pacifico tropical ocidental a nordeste da Australia, durante os invernos de maxima frequencia de ocorrencia de Geadas Generalizadas (GG) no centro-leste da Argentina, (regiao conhecida como Pampa Umida - PU), atua como disparador de ondas de Rossby, as quais se propagam ate o continente, favorecendo assim a ocorrencia daqueles eventos. O padrao de propagacao obtido nas simulacoes numericas com um modelo baroclinico global, mostra o predominio de um numero de onda 3. Adicionalmente, foram analisadas as correlacoes do vento meridional em altos e baixos niveis observados para os eventos de GG, selecionados dentro dos invernos de maxima frequencia de ocorrencia desses eventos. O vento meridional global em 250hPa apresenta regioes com correlacao estatisticamente significativa com o vento meridional medio na PU. A configuracao obtida no caso do vento meridional global em 250hPa, correlacionado com o vento meridional na PU, pode estar associada ao padrao de propagacao das ondas simuladas numericamente a partir da forcante tropical. Igualmente importantes e significativos sao os valores de correlacao do vento sul nos baixos niveis, em particular para toda regiao da PU. O padrao de ondas simulado esta bem representado pelas significativas correlacoes entre o vento meridional hemisferico em altos niveis e a temperatura no dia de evento de GG.

Comparação de Metodologias de Preenchimento de Falhas em Dados Meteorológicos para Estações no Sul do Brasil

Abstract The network of weather stations in Brazil is very recent, with few stations in the country possessing data over more than100 years. In addition, many of the series from these stations present missing data, either due to lack of measurement (inthe case of conventional stations) or due to equipment failures (in the case of automatic stations). There are differentmethods in the literature for filling these gaps. In this work, six methods are compared and applied to series of knownmonthly data for mean compensated temperature and precipitation for weather stations located in the State of RioGrandedoSul,inSouthernBrazil.Theresultsformeancompensatedtemperaturesuggestthatmultiplelinearregressionmethods and regional weighing are best suited for estimating missing data, while for precipitation there was no superiormethod. Keywords: meteorological stations, missing data, gap filling methodologies, compensated mean temperature,precipitation. 1. Introducao Um dos grandes problemas que surgem ao se traba-lhar com dados medidos em estacoes meteorologicas e aincompletude destes. Esta falta de informacoes pode serdevidoaumafalhanoequipamento(seesteforautomatico)ou a uma falta de observador (se esta for uma estacaoconvencional). Como estes dados serao utilizados para di-versos fins de pesquisa, a necessidade de metodos parapreencher estas falhas e de grande interesse. Ha uma amplavariedadedemetodosparaopreenchimentodestaslacunas,desde tecnicas simples como o calculo da media aritmeticaentre dados oriundos de estacoes vizinhas, ate metodosmais apurados, como redes neurais, as quais sao caracte-rizadas por algoritmos computacionais robustos. De formageral, os metodos sao baseados em formulas estatisticas ou

SPATIAL VARIABILITY OF AIR TEMPERATURE IN SOUTHERN BRAZIL BETWEEN 1961-2011

Temperature is one of the most important variables used in climate studies. Changes in its time series can cause various social and political impacts, affecting diverse sectors of society, such as agriculture, for example. Southern Brazil is a region that relies heavily on agriculture, contributing to national production. Therefore, it is important to check the air temperature characteristic, i.e., its spatial pattern in this region. For this, daily data of minimum and maximum temperature of the air of the National Institute of Meteorology were used in the period from 1961 to 2011. The statistical technique of cluster analysis was applied to identify the homogeneous regions of temperature and the boxplot for the characterization of each an. In general, the results showed maximum values of temperatures in the west of Rio Grande do Sul. The regions of minimum temperatures presented a more homogenous pattern, with averages around 15 oC. The regions of the maximum temperatures showed average values oscillating between 22 oC and 28 oC.