Cláudia Rejane Jacondino de Campos

Lagrangian stochastic dispersion modelling for the simulation of the release of contaminants from tall and low sources

A Lagrangian particle model is used to study the dispersion of pollutants released in two different tracer experiments: Prairie Grass and Copenhagen. The model is based on a generalized form of the Langevin equation. Turbulence inputs are parameterized according to a scheme able to generate continuous values in all stability conditions and in all heights in the planetary boundary layer. Predicted values of ground-level concentration agree quite well with observed ones. The major progress of this paper is as follows: For air quality modeling it is highly necessary to include a parameterization that allows a correct description of the turbulent transport of contaminants released simultaneously from low and tall sources.

Impacto de sistemas meteorológicos no regime hídrico do Rio Grande do Sul em 2006

In this work were realized the seasonal determination and analysis of Water Balance (WB) and the analysis of the Meteorological Systems (MS) impact in the hydric regime for the Rio Grande do Sul State (RS) in 2006. Air temperature and rainfall monthly data from 2006, distributed in 16 surface meteorological stations of the RS were used to calculate the WB. The methods proposed by Thornthwaite & Mather (1955) and Thornthwaite (1948) were used to calculate the WB and the evapotranspiration, respectively. The impact of MS in the hydric regime of the RS in 2006 was analyzed using data of occurrence of Frontal System (FS), Mesoscale Convective System (MCS) and Severe Events (SE). The 2006 RS rainfall distribution was uniform in the four periods of the year, with higher rainfall volume in the northern half of RS, where there was no lack of water in 2006. In the southern half of RS in 2006 there was lack of water in JFM and in OND in the coastal region. The factors that contributed to water availability during 2006 in the northern half and lack of water in the southern half of RS in JFM (Jan, Feb, Mar) and in OND (Oct, Nov, Dec) in the coastal region were: MCS and SE higher frequency in the northern half; FS lower frequency in this year in the southern half of RS in relation to the normal climatological data and the ENSO (El Nino South Oscillation) acting whose configuration in 2006 caused dry spell in the Brazil south region.

Características físicas dos sistemas convectivos de mesoescala que afetaram o Rio Grande do Sul no período de 2004 a 2008

A passagem de Sistemas Convectivos de Mesoescala (SCM) sobre uma regiao causa impactos em superficie, pois geralmente esta associada a precipitacao intensa, fortes rajadas de vento e granizo. Esse fenomeno bastante comum na regiao sul do Brasil afeta o Rio Grande do Sul (RS) e causa prejuizos a sua economia. Portanto o estudo dos SCM que atingem o RS e de grande importância, pois alem de permitir um maior entendimento do tempo e do clima da regiao tambem fornece subsidios aos tomadores de decisao. Assim, o objetivo deste trabalho foi estudar as caracteristicas fisicas sazonais dos SCM cuja genese e manutencao ocorreu ao sul de 20oS, que apresentaram ciclo de vida de no minimo 6 h, que tiveram nascimento espontâneo e dissipacao normal e que afetaram a regiao que cobre o RS durante o periodo de 2004 a 2008, utilizando a tecnica ForTrACC (Forecasting and Tracking of Active Cloud Clusters). Foram utilizadas as imagens brutas do satelite GOES (Geostationary Operational Environmental Satellite) do canal 4, com resolucao espacial no seu ponto subsatelite de 4 km x 4 km e resolucao temporal de ½ hora, do periodo de 01/01/2004 a 31/12/2008. Essas imagens foram fornecidas pela Divisao de Satelites Ambientais do Centro de Previsao de Tempo e Estudos Climaticos do Instituto Nacional de Pesquisas Espaciais (DSA/CPTEC/INPE) e serviram como base de dados para a utilizacao da tecnica ForTrACC. Os resultados para o periodo de estudo mostraram que: i) os SCM que afetaram o RS apresentaram maior numero de ocorrencia no periodo mais quente do ano (JFM); ii) nos quatro trimestres do periodo de estudo a maioria dos SCM que afetou o RS (64,7%) apresentaram tempo de vida entre 6 e 12h; iii) SCM com maior tempo de vida cobrem areas maiores; iv) a temperatura minima (Tir) apresentou valores medios menores nos SCM observados em JFM e OND; v) em todos os periodos do ano em torno de 6,4% dos SCM apresentaram formato mais linear, aproximadamente 64,0% apresentaram formato irregular e em torno de 29,6% apresentaram formato mais circular; vi) valores menores de Tir estao relacionados a SCM com formato mais proximo do formato circular (excentricidade igual ou maior do que 0,5) e com maior duracao; vii) as 3 fases do ciclo de vida dos SCM que afetaram o RS podem ocorrer de forma distribuida ao longo do dia; viii) em todos os periodos do ano os nascimentos dos SCM que afetaram o RS ocorrem predominantemente dentro e em torno da grade que cobre o RS, com tendencia a iniciarem mais no lado oeste da grade sobre o continente; ix) em todos os trimestres ha uma tendencia de a trajetoria media preferencial ser de oeste para leste.

A ventilação e a fumaça ambiental de cigarros

A fumaca ambiental de cigarros (FAC) e uma das principais contribuintes para o aumento da concentracao e da exposicao a particulas em ambientes fechados. E comprovado que muitos de seus compostos quimicos sao toxicos ou cancerigenos e que sua inalacao pode causar varios danos a saude. Embora, salvo em areas especificadas, proibido por lei, o fumo em recintos coletivos e comum no Brasil e, na maioria dos casos, as areas destinadas a ele, quando existentes, nao sao devidamente isoladas, prejudicando os nao-fumantes. A industria do tabaco e a da hospitalidade vendem a ventilacao como a solucao desse problema, mas estudos indicam que ela nao o e. Este artigo aborda a problematica da exposicao a FAC por seus aspectos ligados a saude e a poluicao.

Análise Sazonal das Regiões do Rio Grande do Sul Atingidas por Eventos Severos Gerados por SCM no Período de 2004 a 2008

Disaster episodes caused by severe meteorological phenomena, also known as Severe Events (SE), such as windstorms, hail and flood have been studied extensively due to the hazard posed to society. One of the meteorological systems that is fairly common in Rio Grande do Sul state (RS), Brazil, and that is often associated with the SE are Mesoscale Convective Systems (MCS). Since the economy of RS is mostly based on agriculture, which is an activity very susceptible to changes in weather, economic losses caused by SE in RS are rather frequent. Given this point, the objective of this work was to analyze the seasonal distribution of regions affected by SE generated by MCSs that reached RS (SE MCSRS) in the period from 2004 to 2008. For this study, different data sources were used: SE reports and municipalities affected by SE (MA SE) obtained from RS Civil Defense data base; trajectories of the MCS that reached RS (MCS RS) based on Forecasting and Tracking of Active Cloud Clusters (ForTrACC) analysis tool; and raw infra-red (channel 4) satellite imagery from GOES 10 and 12 satellites. The results showed that: i) about 45% of the reported SE in RS were associated to MCS RS; ii) 58% of the MASE were affected by MCS RS; iii) the north portion of RS was the most affected by SE MCSRS; iv) windstorm and hail were the types of SEMCSRS that affected the largest number of municipalities and v) JAS (Jul-Aug-Sep) was the quarter that presented the largest number of municipalities affected by SE SCMRS (MA SE-MCSRS).

Análise do comportamento morfológico e radiativo de um sistema convectivo de mesoescala inferido via imagens de satélite

This article conducts a case study describing the radiational and morphological characteristics of a Mesoscale Convective System (MCS) responsible for the highest precipitations rates observed over Rio Grande do Sul State, Brazil, within the period spanning from November 2002 to February 2003. To that end, the FORecasting and TRAcking of the evolution of Cloud Clusters (ForTrACC) was used as the main tool. The selected case refers to the February 19 and 20, 2003 MCSevent that caused high rainfall rates reported by the surface meteorological stations. This MCS displayed a life span of 23 hours, initiating at 13 UTC of February 19, reaching its mature stage at 04 UTC and dissipating at 11:30 UTC of the following day. During this entire period the MCS displayed cold tops with brightnesstemperatures below 210 K. The behaviour of the MCS followed that described in typical conceptual models, where early strong convection is followed by lower values of brightness temperature, and then display area expansion in its mature stage. We also found distinct relations between minimum brightness temperatures obtained from satellite imagery and precipitation rates reported at the surface during the life cycle of the MCS. The conclusion is that the data collected from only two surface stations could not allow the determination of the clear-cut agreement between the radiative characteristics of the MCS observed by satellite and precipitation rates measured at the surface.

Eventos Severos Que Afetaram o Rio Grande do Sul em 2009

In this study was analyzed the seasonal distribution of the number of days with severe events occurred in Rio Grande do Sul in 2009 (SE RS ), the regions affected by these SE RS , the impact of the SERS which has presented the highest daily frequency, and has reached the greatest number of municipalities. Data of SERS daily occurrence and municipalities affected by these SE RS (MA SE ) from 01/01/2009 to 12/31/2009, obtained from CEDCRS (Coordenadoria Estadual de Defesa Civil do Rio Grande do Sul) database, were used. The results showed that: there were occurrences of SE RS in ~26% of the days in 2009; ~61% of the Rio Grande do Sul municipalities were hit by SE in 2009, and the worst-hit region was the Northwestern Rio-Grandense. We also observed that the higher occurrence of SE RS and MA SE in OND (Oct., Nov., Dec.) was due to seasonal atmospheric conditions characteristics of the region associated to the role of a moderated El Nino. In 2009, the windstorm was the SE that showed the highest daily frequency; reached the highest number of municipalities; generated emergency situation in ~94% of occurrences; reached more than 100 thousand people, and caused agriculture damage in ~ 22% of the municipalities affected. In addition, the quarter and the Rio Grande do Sul region most affected by windstorm in 2009 were OND and Northwest Rio-Grandense, respectively.

ENVIRONMENTAL CHARACTERISTICS RELATED TO HAIL OCCURRENCE IN SOBRADINHO-RS IN DECEMBER 2008

This work analyzed thermodynamic and synoptic environmental characteristics associated with the occurrence of hail generated by a Mesoscale Convective System (MCS) that reached Sobradinho in Rio Grande do Sul (RS) from December 09 to 10, 2008 as well as morphological and radiative behavior of this MCS. These analyses allowed highlight the main atmospheric conditions which contributed for the occurrence of this event. The results showed that the atmospheric conditions observed in the region (heat and moisture transport at low levels and intense updrafts) were extremely favorable to formation and development of the MCS that began in December 09, 2008, which favored the hail occurrence on the same day in Sobradinho and precipitation in RS in December 09 to 10, 2008.

Evento Extremo de Precipitação Observado no Norte do Rio Grande do Sul

This paper analyzes atmospheric conditions related to an extreme rainfall event that reached Northern of Rio Grande do Sul (RS) in July 10, 2007. Different data sources were used: rainfall daily data from 16 meteorological surface stations of RS to verify the rainfall registered on RS during the event; infra-red (channel 4) satellite imagery from GOES 10 (Geostationary Operational Environmental Satellite), to analyze the evolution of meteorological system that generated the event; surface and altitude synoptic charts from July 10, 2007 at 00 UTC to analyze the meteorological systems acting on the RS and data from NCEP-CFSR Reanalysis (National Centers for Environmental Prediction -- Climate Forecast System Reanalysis), to analyze the large-scale environment associated with the event. The results showed that the circulation in low-level of the atmosphere contributed to supply the study area with large amount of heat and humidity. This condition combined with the occurrence of Frontal System observed from July 09, 2007 contributed to the organization of atmospheric instability and convective cloudiness observed, favoring the occurrence of the extreme rainfall registered in Northern RS in July 10, 2007.

THE WATER REGIME OF RS DURING THE EL NIÑO-SOUTHERN OSCILLATION (ENSO )EVENTS OF THE YEARS 1987 AND 1999

In this work were determined and analyzed the seasonal water balance (WB) anomalies for 1987 and 1999 in relation to the Rio Grande do Sul (RS) climatic WB in the period from 1977 to 2006 to evaluate the El Nino (EN) 1987 and La Nina (LN) 1999 impact in the RS water regime, detecting periods and regions with excess or deficit of water. To calculate the WB were used air temperature and rainfall data, obtained from the National Institute of Meteorology. The water balances were calculated by Thornthwaite and Mather method, and evapotranspiration by the Thornthwaite method. The results showed that El Nino-Southern Oscillation (ENSO) affected the water regime of the analyzed years. The 1987 year was wetter than normal in most the RS, except in the extreme south the state where it was found negative precipitation anomalies and deficit of water, due to the occurrence of EN. On the other hand, 1999 was a year drier than the climatology from 1977 to 2006, due to the occurrence of LN. Excess of water observed in 1999 were registered on RS north and northwest regions.