Eventos e impactos sociais e ambientais asociados a sistemas meteorológicos na América do Sul em janeiro 2008

Ponencia presentada en: XXX Jornadas Científicas de la AME y el IX Encuentro Hispano Luso de Meteorología celebrado en Zaragoza, del 5 al 7 de mayo de 2008

Início da estaçao chuvosa na bacia Amazonica central com dados de radiaçao de onda longa anti-simétricos em relaçao ao Equador

Ponencia presentada en: XXX Jornadas Científicas de la AME y el IX Encuentro Hispano Luso de Meteorología celebrado en Zaragoza, del 5 al 7 de mayo de 2008

Efeitos do ENOS na precipitaçao na América do Sul antes e depois de 1977

Ponencia presentada en: XXX Jornadas Científicas de la AME y el IX Encuentro Hispano Luso de Meteorología celebrado en Zaragoza, del 5 al 7 de mayo de 2008

Diferenças associadas à oscilaçao decenal do Pacífico nas relaçoes interanuais de precipitaçao na América do Sul e temperatura da superficie do mar

Ponencia presentada en: XXX Jornadas Científicas de la AME y el IX Encuentro Hispano Luso de Meteorología celebrado en Zaragoza, del 5 al 7 de mayo de 2008

Seasonal variability of relative evapotranspiration in Campinas (SP): climatic characterization and trends analysis

O conhecimento da probabilidade de ocorrência da razão entre a evapotranspiração real e a potencial (ETR/ETP ou evapotranspiração relativa), é fundamental para a determinação de épocas mais adequadas de plantio/semeadura, podendo constituir-se em importante etapa para o zoneamento de riscos climáticos. Por meio da função densidade de probabilidade beta, determinou-se a probabilidade de ocorrência de valores de ETR/ETP na região de Campinas (SP), com base no período entre 1890 ae2006. A mesma análise foi realizada para os períodos de 1890 a 1918, 1919 a 1947, 1948 a 1976 (vinte e nove anos) e 1977 a 2006 (trinta anos), a fim de investigar a variabilidade das probabilidades de ocorrência desse parâmetro. As análises permitiram inferir que: a) em janeiro são observadas as maiores probabilidades de ocorrência de valores de ETR/ETP = 1; b) sob o ponto de vista de reposição das perdas por evapotranspiração, os períodos mais críticos do calendário agrícola local ocorrem em abril, outubro e no primeiro decêndio de novembro; e c) método empregado não nos permite detectar significativas alterações na freqüência temporal dos valores de ETR/ETP durante o período analisado.The knowledge of the probability of occurrence of the ratio between the actual evapotranspiration and the potential evapotranspiration (ETR/ETP) is fundamental to choose the best sowing/plantation seasons, and might be important to the climatic risks zoning. Using the beta probability density function it was determined the probability of occurrence of the ETR/ETP values in the region of Campinas, São Paulo State, Brazil for the period from 1890 to 2006. The same analysis was carried out considering the years from 1890 to 1918, 1919 to 1947, 1948 to 1976 (twenty-nine years) and 1977 to 2006 (thirty years), in order to investigate the variability of the ETR/ETP probabilities of occurrence. The analyses allowed to infer that: a) The ETR/ETP =1 cases have the largest probability of occurrence in January; b) under the point of view of the replacement of evapotranspiration losses, the most critical periods for the local agricultural calendar are in April, October and the first 10-day interval of November; and c) The method employed does not allow us to detect significant alterations in the frequency of ETR/ETP values during the analyzed period

Sample variability of monthly precipitation series in two regions of Brazil: Pelotas-RS and Campinas-SP

O presente trabalho avaliou a variabilidade amostral dos parâmetros da distribuição gama, relativos a séries mensais de precipitação pluvial, nas regiões de Campinas-SP e Pelotas-RS, que têm dados para os períodos de 1890-2006 e 1890-2005, respectivamente. Assim, os espaços amostrais considerados foram de 58, 39 e 29 anos para Campinas e 58 e 29 anos para Pelotas. As análises foram feitas usando o teste da razão da máxima verossimilhança. Os resultados apontaram significativas alterações amostrais. Não houve indicações de tendências contínuas (redução ou aumento) no regime mensal de precipitação pluvial na região de Campinas-SP. Em contrapartida, esse teste indicou, para a localidade de Pelotas-RS, tendência de elevação no regime desse elemento meteorológico ocorrida entre as amostras relativas aos anos de 1948 a 1976 e 1977 a 2005.The present work evaluated the sample variability of the Gamma distribution parameters fitted to monthly precipitation series in the regions of Campinas-SP and Pelotas-RS, which have data for the 1890-2006 and 1890-2005 periods, respectively. So, the sample spaces considered were of 58, 39 and 29 years for Campinas, and of 58 and 29 years for Pelotas. Analyses were done using the likelihood ratio test. The analyses showed significant sample alterations. No trend was detected in monthly precipitation series of the region of Campinas-SP. Increasing trends was detected in the monthly precipitation series of the region of Pelotas-RS considering the 1948 to 1976 and 1977 to 2005 samples

Variabilidade do perfil vertical de monóxido de carbono sobre a Região Metropolitana de Manaus e sua relação com a queima de biomassa

The present study analyzes the temporal variability of carbon monoxide (CO) over the Manaus Metropolitan Region (MMR) and its relations with nearby fires based on data obtained by the environmental satellite AQUA, for the 2003–2020 period. For this purpose, wavelet transform analyses and wavelet coherence analyses were used. The results show a well-defined seasonal behavior, with an increase and decrease in mean CO concentrations during dry and wet seasons, respectively. Semiannual and annual scales represent around 95 % of CO temporal variability in lower troposphere (500 to 1,000 hPa) and are associated with rains and fires dynamics in the region. In terms of interannual variability, multiple variability scales (1.2–2, 2.5–3 and 4.5–6 years) were observed, which explain around 10–15 % of concentration variability near surface. The results suggest that climatic variations, associated with the tropical Pacific and Atlantic sea surface temperature variations, on these different time scales, affect rain dynamics and, consequently, fires and CO concentration. Specifically, in 2015/16, the combined effect from different variability scales acted to prolong the dry period over the region, which contributed to increase fires and the CO to reach higher values compared to previous years. These results show a new aspect of the importance of evaluating the combined effect of different climate variability scales on CO concentrations in the atmosphere.O presente estudo analisa a variabilidade temporal do gás monóxido de carbono (CO) sobre a Região Metropolitana de Manaus (RMM) e sua relação com as queimadas com base em informações obtidas pelo satélite ambiental AQUA, para o período entre 2003 e 2020. Para tal, foram realizadas análises de transformada de ondeleta e análises de coerência e fase da ondeleta. Os resultados apontam para um comportamento sazonal bem definido, com aumento das concentrações médias de CO durante a estação seca e redução na estação chuvosa. As escalas semianual e anual representam cerca de 95% da variabilidade temporal do CO na baixa troposfera (500 a 1.000 hPa) e estão associadas à dinâmica das chuvas e queimadas na região. Com relação à variabilidade interanual, observaram-se múltiplas escalas de variabilidade (1,2–2, 2,5–3 e 4,5–6 anos), que explicam juntas em torno de 10–15 % da variabilidade das concentrações próximas à superfície. Os resultados sugerem que variações climáticas, associadas às variações da temperatura da superfície do mar nos oceanos Pacífico e Atlântico tropicais, nessas diferentes escalas de tempo, afetam a dinâmica das chuvas e, consequentemente, as queimadas e a concentração de CO. Especificamente em 2015/16, o efeito combinado das diferentes escalas de variabilidade atuou para prolongar o período seco sobre a região, o que contribuiu para o aumento das queimadas e para que o CO alcançasse maiores valores em relação aos anos anteriores. Tais resultados mostram um aspecto novo sobre a importância de avaliar o efeito combinado de diferentes escalas de variabilidade climática nas concentrações de CO na atmosfera, particularmente em anos extremos

Spatio-temporal analysis of the droughts in Cali, Colombia and their primary relationships with the El Nino-Southern Oscillation (ENSO) between 1971 and 2011

This paper analyzed the spatio-temporal variability of droughts in Cali, Colombia and their primary relations to the El Nino Southern Oscillation (ENSO). The Standardized Precipitation Index (SPI) was used to detect drought events from monthly rainfall data of 24 stations well spread over Cali during 1971-2011. The SPI provided the drought intensity, magnitude, frequency, and the minimum rainfall thresholds, mainly on an annual scale (SPI-12). Eighty percent of the stations reported four events with dry conditions in Cali: 1976-1977, 1983-1984, 1990-1992 and 2009-2010. The ENSO influence was evaluated using the correlation and wavelet transform analyses. Significant (non-significant) negative correlations between SPI-12 in the northern (southern) part of Cali, the multivariate ENSO Index (MEI), and Sea Surface Temperature (SST) Nino 3.4 and Nino 4 indices were observed. The wavelet coherence analysis showed significant coherencies between ENSO and SPI-12: at interannual scale (4-6 years), the phase difference of-135o generates a lag of 6-9 months between the minimum peak of the SPI-12 and the maximum peak of the indices. On the quasi-biennial scale (2-3 years), the phase difference of-180o suggests that the maximum wet (dry) conditions coincide with the mature stage of the La Nina (El Nino) event; and on the decadal scale (8-16 years), the decreases (increases) in rainfall precede the El Nino (La Nina) mature stage by approximately 10-18 months. These results are relevant for seasonal forecasting, since changes in SST in the equatorial Pacific may take place 6-18 months ahead of the dry conditions in Cali. © 2020 Universidad Nacional Autonoma de Mexico

A influência do evento El Niño - Oscilação Sul e Atlântico equatorial na precipitação sobre as regiões norte e nordeste da América do Sul

The impacts of anomalous events in the Pacific Ocean associated with the El Niño - Southern Oscillation (ENSO) on rainfall over northern and northeastern regions of South America were evaluated for the period from 1900 to 2007 using composite analyses. The El Niño (La Niña) events in the Pacific, that together with a cold (warm) Atlantic Equatorial Mode (AEM) form an interbasin gradient between the Pacific and Atlantic were analyzed considering separately those for which the gradient forms during the ENSO onset phase from those for which the gradient forms during the ENSO demise phase. The results show that the rainfall pattern over the northern and northeastern region of South America is reinforced under an interbasin gradient during the initial phase of the ENSO event. In this case, a possible explanation is that the AEM with opposite sign of the ENSO event in its onset stage creates favorable conditions for the development of an interhemispheric gradient in the Tropical Atlantic acting in the same direction of the interbasin gradient, and collaborating to reinforce the El Niño (La Niña) effect on the precipitation. On the other hand, for ENSO events for which the interbasin gradient forms in the demise stage, the impact on the precipitation is more significative in the northern and central-western regions of the basin. A possible explanation for these differences is linked to the alterations in the east-west atmospheric circulation associated with the east-west gradient of the SST anomalies. The result of this study might be useful mainly for climate monitoring purposes

Estudo do fenômeno da ilha de calor na cidade de Manaus/AM: Um estudo a partir de dados de sensoriamento remoto, modelagem e estações meteorológicas

The heat island phenomenon (HI) in the city of Manaus was studied using the urban climate modeling with the Weather Research and Forecasting (WRF) model and meteorological weather station data. The surface temperature (ST) data from the environmental satellite MODIS Aqua, product MYD11A2 with a horizontal resolution of 1 km by 1 km for the period 2002 to 2012 were used to evaluate the urbanization process in Manaus city. A case study was conducted with the simulated ST and air temperature (AT) for the months of August and September 2009, which were compared respectively with the satellite data and meteorological weather station data. The spatial distribution of ST in the city was identified, and the ST differences between the urban and the forest areas and between the urban and river areas were quantified. The ST difference across the longitude bands 60,03° W to 59,97° W and across the latitude bands 3,09° S a -3,03° S were analyzed with WRF data and MODIS data. The intensity of the HI estimated with the AT from the model and the meteorological stations were on average respectively of 1,87 °C and 1,80 °C, consistent with previous results. Therefore, the simulated AT can be used to estimate the intensity ofHI in Manaus. © 2016, Sociedade Brasileira de Meteorologia. All Rights reserved