. On February 15, 2022, the city of Petrópolis in Rio de Janeiro, Brazil, received an unusually h... more . On February 15, 2022, the city of Petrópolis in Rio de Janeiro, Brazil, received an unusually high volume of rain within three hours (258 mm). It resulted in flash floods and subsequent landslides that caused 231 fatalities, the deadliest landslide disaster recorded in Petrópolis. In this paper, we analyzed the root cause and the key triggering factors of this landslide disaster by assessing the spatial relationship of landslide occurrence with various environmental factors. Rainfall data were retrieved from 1977 to 2022, while other remote sensing data from 1985 to 2020, were utilized to map the landslide scars, soil moisture, terrain attributes, line-of-sight displacement (land surface deformation), and urban sprawling .. to. The results showed that the average rainfall for February 2022 was 200 mm, the heaviest recorded in Petrópolis since 1932. From the rainfall spatial distribution, heavy rainfall was also recorded mostly in regions where the landslide occurred. As for terrain, 23 % of slopes between 45–60° had landslide occurrences and east-facing slopes appeared to be the most conducive for landslides as they recorded landslide occurrences of about 9 to 11 %. Regarding the soil moisture, higher variability was found in the lower altitude (842 m) where the residential area is concentrated. From our land deformation assessment, the area is geologically stable, and the landslide occurred only in the thin layer at the surface of the 1,700 buildings found in the region of interest, 1,021 are on the slope between 20 to 45° and about 60 houses were directly affected by the landslides. As such, we conclude that the heavy rainfall was not the only cause responsible for the catastrophic event of February 15, 2022; a combination of unplanned urban growth on slopes between 45–60°, removal of vegetation, and the absence of inspection were also significant elements of this natural disaster.
The eddy covariance technique was used to estimate the sensible and latent heat flux between the ... more The eddy covariance technique was used to estimate the sensible and latent heat flux between the atmosphere and the Pampa Biome in the period from 20 November 2013 to 20 November 2014. Annual Evapotranspiration (ET) was 1021 mm, corresponding to 55% of the annual precipitation. The ET is highly correlated with the net radiation (97%). The Bowen ratio was indicated that most of the available energy was used for the evaporation. The evaporative fraction remained about average, with greater variability in the colder months.
Air Pollution Modeling and Its Application XVII, 2006
... References Acevedo, OC, Moraes, OLL, Silva, R., 2002, Turbulence Observations at the Edge of ... more ... References Acevedo, OC, Moraes, OLL, Silva, R., 2002, Turbulence Observations at the Edge of a Cliff, 15th Symposium on Boundary Layers and Turbulence, Wageningen, The Netherlands, 592-595. Bradley, EF, 1980, 'An ...
Este artigo apresenta dois estudos de caso com objetivo de investigar a interação do vento local ... more Este artigo apresenta dois estudos de caso com objetivo de investigar a interação do vento local no interior de um vale, com o vento sinótico. A direção e a velocidade do vento local são obtidas de dados de resposta lenta medidos em um trecho leste/oeste do vale do rio da Prata, localizado na região de Nova Roma do Sul, Estado do Rio Grande do Sul. Os dados sinóticos da direção e velocidade dos ventos foram observados às 00, 12 e 18 TMG, em três estações meteorológicas de superfície localizadas na mesorregião do vale estudado. O padrão sinótico é avaliado através de campos meteorológicos construídos com a reanálise do NCEP-NCAR. A análise sinótica e a avaliação empírica do vento local são realizadas com a ajuda de outras variáveis medidas no fundo do vale, tais como radiação solar incidente e temperatura do ar. Os resultados mostram a existência de superposição das forçantes, térmica e canalizada, durante a madrugada e parte da manhã. Porém, quando a temperatura do ar durante a madr...
The Weather and Research Forecast model is tested over South America in different configurations ... more The Weather and Research Forecast model is tested over South America in different configurations to identify the one that gives the best estimates of observed surface variables. Systematic, nonsystematic, and total errors are computed for 48-h forecasts initialized with the NCEP Global Data Assimilation System (GDAS). There is no unique model design that best fits all variables over the whole domain, and nonsystematic errors for all configurations differ little from one another; such differences are in most cases smaller than the observed day-to-day variability. An ensemble mean consisting of runs with different parameterizations gives the best skill for the whole domain. Surface variables are highly sensitive to the choice of land surface models. Surface temperature is well represented by the Noah land model, but dewpoint temperature is best estimated by the simplest land surface model considered here, which specifies soil moisture based on climatology. This underlines the need for...
Experimentally characterizing evapotranspiration (ET) in different biomes around the world is an ... more Experimentally characterizing evapotranspiration (ET) in different biomes around the world is an issue of interest for different areas of science. ET in natural areas of the Brazilian Pampa biome has still not been assessed. In this study, the actual ET (ETact) obtained from eddy covariance measurements over two sites of the Pampa biome was analyzed. The objective was to evaluate the energy partition and seasonal variability of the actual ET of the Pampa biome. Results showed that the latent heat flux was the dominant component in available energy in both the autumn–winter (AW) and spring–summer (SS) periods. Evapotranspiration of the Pampa biome showed strong seasonality, with highest ET rates in the SS period. During the study period, approximately 65% of the net radiation was used for the evapotranspiration process in the Pampa biome. The annual mean ET rate was 2.45 mm d−1. ET did not show to vary significantly between sites, with daily values very similar in both sites. The wat...
This study evaluates the reliability of the Weather Research and Forecasting (WRF) to simulate a... more This study evaluates the reliability of the Weather Research and Forecasting (WRF) to simulate a snowfall event in the south of Brazil. The event in August 2013 was considered one of the most intense in recent years in the region with the highest topographic elevations between the states of Rio Grande do Sul (RS) and Santa Catarina (SC). The Snowfall in the mountain region of RS and SC was associated with the configuration involving a polar anticyclone and the intensification of an extratropical cyclone over the Atlantic Ocean. The WRF simulation results demonstrated the model's viability to predict the event, but without the magnitude representation of the phenomenon. The WRF simulation underestimated the results for the accumulated and area of the snowfall region, which may be linked to overestimations of surface and vertical air temperature and liquid water precipitation. These results were attributed to the choice of WRF Single–moment 6–class (WSM6) microphysics and in the...
In this study, the eddy-covariance technique was used to estimate the surface fluxes of carbon (C... more In this study, the eddy-covariance technique was used to estimate the surface fluxes of carbon (CO2) and energy, in the latent (LE) and sensible (H) forms, over a native field ecosystem (pasture). The results show that the ecosystem in question presents a predominant seasonality in its ecological functioning, especially regarding the observations of the LE and CO2 fluxes, with carbon assimilation and evapotranspiration with maximum values during the summer. During the winter season observations point to a lower metabolic state of the ecosystem, with almost zero carbon assimilation (even a carbon source signal inversion) and the evapotranspiration rate falling to 60% of its value in the highest state metabolic activity.
Anais da Academia Brasileira de Ciencias, Jan 16, 2017
Drought is a natural and recurrent phenomenon. It is considered 'a natural disaster' when... more Drought is a natural and recurrent phenomenon. It is considered 'a natural disaster' whenever it occurs in an intensive manner in highly populated regions, resulting in significant damage (material and human) and loss (socioeconomic). This paper presents the efforts developed to monitor the impact of drought in the semiarid region of Northeast Brazil. In this scope, information from different sources is compiled to support the evaluation and identification of impacted municipalities, with the main objective of supporting emergency actions to mitigate their impact. In the semiarid region of Brazil there are frequent occurrences of dry periods during the rainy season, which, depending on the intensity and duration, can cause significant damage to family-farmed crops, with a farming system characterized by low productivity indices. However, rain-fed agriculture has great economic expression and high social importance due to the region is densely occupied, and contributes to the...
Anais da Academia Brasileira de Ciencias, Jan 14, 2017
This study discusses the climatological aspects of the most severe drought ever recorded in the s... more This study discusses the climatological aspects of the most severe drought ever recorded in the semiarid region Northeast Brazil. Droughts are recurrent in the region and while El Nino has driven some of these events others are more dependent on the tropical North Atlantic sea surface temperature fields. The drought affecting this region during the last 5 years shows an intensity and impact not seen in several decades in the regional economy and society. The analysis of this event using drought indicators as well as meteorological fields shows that since the middle 1990s to 2016, 16 out of 25 years experienced rainfall below normal. This suggests that the recent drought may have in fact started in the middle-late 1990s, with the intense droughts of 1993 and 1998, and then the sequence of dry years (interrupted by relatively wet years in 2007, 2008, 2009 and 2011) after that may have affected the levels of reservoirs in the region, leading to a real water crisis that was magnified by...
In 1972 Kaimal et al. published a paper on the behaviour of spectra of turbulence in the surface ... more In 1972 Kaimal et al. published a paper on the behaviour of spectra of turbulence in the surface layer, based on data from Kansas. In that paper, which is a classical reference in the field, it was observed that the stable logarithmic spectra of velocity components with appropriate ...
. On February 15, 2022, the city of Petrópolis in Rio de Janeiro, Brazil, received an unusually h... more . On February 15, 2022, the city of Petrópolis in Rio de Janeiro, Brazil, received an unusually high volume of rain within three hours (258 mm). It resulted in flash floods and subsequent landslides that caused 231 fatalities, the deadliest landslide disaster recorded in Petrópolis. In this paper, we analyzed the root cause and the key triggering factors of this landslide disaster by assessing the spatial relationship of landslide occurrence with various environmental factors. Rainfall data were retrieved from 1977 to 2022, while other remote sensing data from 1985 to 2020, were utilized to map the landslide scars, soil moisture, terrain attributes, line-of-sight displacement (land surface deformation), and urban sprawling .. to. The results showed that the average rainfall for February 2022 was 200 mm, the heaviest recorded in Petrópolis since 1932. From the rainfall spatial distribution, heavy rainfall was also recorded mostly in regions where the landslide occurred. As for terrain, 23 % of slopes between 45–60° had landslide occurrences and east-facing slopes appeared to be the most conducive for landslides as they recorded landslide occurrences of about 9 to 11 %. Regarding the soil moisture, higher variability was found in the lower altitude (842 m) where the residential area is concentrated. From our land deformation assessment, the area is geologically stable, and the landslide occurred only in the thin layer at the surface of the 1,700 buildings found in the region of interest, 1,021 are on the slope between 20 to 45° and about 60 houses were directly affected by the landslides. As such, we conclude that the heavy rainfall was not the only cause responsible for the catastrophic event of February 15, 2022; a combination of unplanned urban growth on slopes between 45–60°, removal of vegetation, and the absence of inspection were also significant elements of this natural disaster.
The eddy covariance technique was used to estimate the sensible and latent heat flux between the ... more The eddy covariance technique was used to estimate the sensible and latent heat flux between the atmosphere and the Pampa Biome in the period from 20 November 2013 to 20 November 2014. Annual Evapotranspiration (ET) was 1021 mm, corresponding to 55% of the annual precipitation. The ET is highly correlated with the net radiation (97%). The Bowen ratio was indicated that most of the available energy was used for the evaporation. The evaporative fraction remained about average, with greater variability in the colder months.
Air Pollution Modeling and Its Application XVII, 2006
... References Acevedo, OC, Moraes, OLL, Silva, R., 2002, Turbulence Observations at the Edge of ... more ... References Acevedo, OC, Moraes, OLL, Silva, R., 2002, Turbulence Observations at the Edge of a Cliff, 15th Symposium on Boundary Layers and Turbulence, Wageningen, The Netherlands, 592-595. Bradley, EF, 1980, 'An ...
Este artigo apresenta dois estudos de caso com objetivo de investigar a interação do vento local ... more Este artigo apresenta dois estudos de caso com objetivo de investigar a interação do vento local no interior de um vale, com o vento sinótico. A direção e a velocidade do vento local são obtidas de dados de resposta lenta medidos em um trecho leste/oeste do vale do rio da Prata, localizado na região de Nova Roma do Sul, Estado do Rio Grande do Sul. Os dados sinóticos da direção e velocidade dos ventos foram observados às 00, 12 e 18 TMG, em três estações meteorológicas de superfície localizadas na mesorregião do vale estudado. O padrão sinótico é avaliado através de campos meteorológicos construídos com a reanálise do NCEP-NCAR. A análise sinótica e a avaliação empírica do vento local são realizadas com a ajuda de outras variáveis medidas no fundo do vale, tais como radiação solar incidente e temperatura do ar. Os resultados mostram a existência de superposição das forçantes, térmica e canalizada, durante a madrugada e parte da manhã. Porém, quando a temperatura do ar durante a madr...
The Weather and Research Forecast model is tested over South America in different configurations ... more The Weather and Research Forecast model is tested over South America in different configurations to identify the one that gives the best estimates of observed surface variables. Systematic, nonsystematic, and total errors are computed for 48-h forecasts initialized with the NCEP Global Data Assimilation System (GDAS). There is no unique model design that best fits all variables over the whole domain, and nonsystematic errors for all configurations differ little from one another; such differences are in most cases smaller than the observed day-to-day variability. An ensemble mean consisting of runs with different parameterizations gives the best skill for the whole domain. Surface variables are highly sensitive to the choice of land surface models. Surface temperature is well represented by the Noah land model, but dewpoint temperature is best estimated by the simplest land surface model considered here, which specifies soil moisture based on climatology. This underlines the need for...
Experimentally characterizing evapotranspiration (ET) in different biomes around the world is an ... more Experimentally characterizing evapotranspiration (ET) in different biomes around the world is an issue of interest for different areas of science. ET in natural areas of the Brazilian Pampa biome has still not been assessed. In this study, the actual ET (ETact) obtained from eddy covariance measurements over two sites of the Pampa biome was analyzed. The objective was to evaluate the energy partition and seasonal variability of the actual ET of the Pampa biome. Results showed that the latent heat flux was the dominant component in available energy in both the autumn–winter (AW) and spring–summer (SS) periods. Evapotranspiration of the Pampa biome showed strong seasonality, with highest ET rates in the SS period. During the study period, approximately 65% of the net radiation was used for the evapotranspiration process in the Pampa biome. The annual mean ET rate was 2.45 mm d−1. ET did not show to vary significantly between sites, with daily values very similar in both sites. The wat...
This study evaluates the reliability of the Weather Research and Forecasting (WRF) to simulate a... more This study evaluates the reliability of the Weather Research and Forecasting (WRF) to simulate a snowfall event in the south of Brazil. The event in August 2013 was considered one of the most intense in recent years in the region with the highest topographic elevations between the states of Rio Grande do Sul (RS) and Santa Catarina (SC). The Snowfall in the mountain region of RS and SC was associated with the configuration involving a polar anticyclone and the intensification of an extratropical cyclone over the Atlantic Ocean. The WRF simulation results demonstrated the model's viability to predict the event, but without the magnitude representation of the phenomenon. The WRF simulation underestimated the results for the accumulated and area of the snowfall region, which may be linked to overestimations of surface and vertical air temperature and liquid water precipitation. These results were attributed to the choice of WRF Single–moment 6–class (WSM6) microphysics and in the...
In this study, the eddy-covariance technique was used to estimate the surface fluxes of carbon (C... more In this study, the eddy-covariance technique was used to estimate the surface fluxes of carbon (CO2) and energy, in the latent (LE) and sensible (H) forms, over a native field ecosystem (pasture). The results show that the ecosystem in question presents a predominant seasonality in its ecological functioning, especially regarding the observations of the LE and CO2 fluxes, with carbon assimilation and evapotranspiration with maximum values during the summer. During the winter season observations point to a lower metabolic state of the ecosystem, with almost zero carbon assimilation (even a carbon source signal inversion) and the evapotranspiration rate falling to 60% of its value in the highest state metabolic activity.
Anais da Academia Brasileira de Ciencias, Jan 16, 2017
Drought is a natural and recurrent phenomenon. It is considered 'a natural disaster' when... more Drought is a natural and recurrent phenomenon. It is considered 'a natural disaster' whenever it occurs in an intensive manner in highly populated regions, resulting in significant damage (material and human) and loss (socioeconomic). This paper presents the efforts developed to monitor the impact of drought in the semiarid region of Northeast Brazil. In this scope, information from different sources is compiled to support the evaluation and identification of impacted municipalities, with the main objective of supporting emergency actions to mitigate their impact. In the semiarid region of Brazil there are frequent occurrences of dry periods during the rainy season, which, depending on the intensity and duration, can cause significant damage to family-farmed crops, with a farming system characterized by low productivity indices. However, rain-fed agriculture has great economic expression and high social importance due to the region is densely occupied, and contributes to the...
Anais da Academia Brasileira de Ciencias, Jan 14, 2017
This study discusses the climatological aspects of the most severe drought ever recorded in the s... more This study discusses the climatological aspects of the most severe drought ever recorded in the semiarid region Northeast Brazil. Droughts are recurrent in the region and while El Nino has driven some of these events others are more dependent on the tropical North Atlantic sea surface temperature fields. The drought affecting this region during the last 5 years shows an intensity and impact not seen in several decades in the regional economy and society. The analysis of this event using drought indicators as well as meteorological fields shows that since the middle 1990s to 2016, 16 out of 25 years experienced rainfall below normal. This suggests that the recent drought may have in fact started in the middle-late 1990s, with the intense droughts of 1993 and 1998, and then the sequence of dry years (interrupted by relatively wet years in 2007, 2008, 2009 and 2011) after that may have affected the levels of reservoirs in the region, leading to a real water crisis that was magnified by...
In 1972 Kaimal et al. published a paper on the behaviour of spectra of turbulence in the surface ... more In 1972 Kaimal et al. published a paper on the behaviour of spectra of turbulence in the surface layer, based on data from Kansas. In that paper, which is a classical reference in the field, it was observed that the stable logarithmic spectra of velocity components with appropriate ...
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