Papers by Silvio Nilo Figueroa
Journal of South American Earth Sciences
Geoscientific Model Development Discussions, 2018
The main features of climate change patterns, as simulated by the coupled ocean-atmosphere versio... more The main features of climate change patterns, as simulated by the coupled ocean-atmosphere version 2.5 of the Brazilian Earth System Model (BESM-OA2.5) are contrasted with those of other 25 CMIP5 models, focusing on temperature, precipitation and atmospheric circulation. The climate sensitivity to quadrupling atmospheric CO 2 concentration is investigated from two techniques: Gregory et al. (2004) and Radiative Kernel (Soden and Held, 2006; Soden et al., 2008) methods. Radiative kernels from both NCAR and GFDL are used in order to decompose the climate feedback responses of CMIP5 models and BESM-OA2.5 into different processes. Applying the Gregory method for equilibrium climate sensitivity (ECS) estimation, we obtain values ranging from 2.07 to 4.74 K for the CMIP5 models and 2.96 K for BESM, which is close to the ensemble mean value (3.30 K ± 0.76). The study reveals that BESM has shown zonally averaged feedbacks estimated from Radiative Kernel within the ensemble standard deviation of the other CMIP5 models. The exceptions are found in the high-latitudes of the Northern Hemisphere, where BESM shows values for lapse-rate and humidity feedbacks marginally out of the limit between minimum and maximum of CMIP5 multi-model ensemble, as well as in the Arctic region and over the ocean near the Antarctic for cloud feedback. Moreover, BESM shows physically consistent changes in the pattern of temperature, precipitation and atmospheric circulation.
This study presents novel insight into the mechanisms of Atlantic Meridional Overturning Circulat... more This study presents novel insight into the mechanisms of Atlantic Meridional Overturning Circulation (AMOC) reduction and its recovery under a warmer climate scenario. An one-thousand-year-long numerical simulation of a global coupled ocean-ice-atmosphere climate model, subjected to a stationary atmospheric radiative forcing, depict a coherent picture of the Arctic sea ice melting as a trigger for the initial AMOC reduction, along with decreases in the northward fluxes of salt and heat. Further atmospheric-driven ocean processes contribute to an erosion of the stable stratification of the fresher, yet colder waters in the surface layers of the North Atlantic, contributing to the recovery of a permanently altered AMOC.
Quarterly Journal of the Royal Meteorological Society
Tropical–extratropical cloud bands are common in South America (SAm), contributing significantly ... more Tropical–extratropical cloud bands are common in South America (SAm), contributing significantly to the total rainy season precipitation. Thus, it is fundamental that climate and weather forecast models correctly represent them and their associated dynamic aspects. Adopting an event‐based framework, we evaluate the performance of two global models in simulating the observed cloud bands over SAm: the Brazilian Global Atmospheric Model version 1.2 (BAM‐1.2) and the Hadley Centre Global Environment Model in the Global Coupled configuration 3.1 (HadGEM3‐GC3.1). Both models reproduce the main characteristics of cloud bands and the dynamical aspects leading to their development and persistence. Nonetheless, the biases in precipitation during simulated cloud bands contribute more than 50% of the bias in total precipitation in some regions. BAM‐1.2 simulates fewer but more persistent cloud bands than observed; HadGEM3‐GC3.1 simulates weaker cloud band activity during early summer and more p...
This study presents novel insight into the mechanisms of Atlantic Meridional Overturning Circulat... more This study presents novel insight into the mechanisms of Atlantic Meridional Overturning Circulation (AMOC) reduction and its recovery under a warmer climate scenario. An one-thousand-year-long numerical simulation of a global coupled ocean-ice-atmosphere climate model, subjected to a stationary atmospheric radiative forcing, depict a coherent picture of the Arctic sea ice melting as a trigger for the initial AMOC reduction, along with decreases in the northward fluxes of salt and heat. Further atmospheric-driven ocean processes contribute to an erosion of the stable stratification of the fresher, yet colder waters in the surface layers of the North Atlantic, contributing to the recovery of a permanently altered AMOC.
Climate resilience and sustainability, Jan 14, 2022
The Climate Science for Service Partnership Brazil (CSSP-Brazil) project provides Brazil and UK p... more The Climate Science for Service Partnership Brazil (CSSP-Brazil) project provides Brazil and UK partners the opportunity to address important challenges faced by the climate modeling community, including the need to develop subseasonal and seasonal prediction and climate projection services. This paper provides an overview of the climate modeling and prediction research conducted through CSSP-Brazil within the context of a framework to advance climate prediction services in Brazil that includes a research-to-services (R2S) and a services-toresearch (S2R) feedback pathway. The paper also highlights plans to advance scientific understanding and capability to produce beneficial climate knowledge and new products to improve climate prediction services to support decisions in various industries in Brazil. Policy-relevant outcomes from climate modeling and prediction exercises illustrated in this paper include supporting stakeholders with climate information provided from weeks to months ahead for (a) improving water management strategies for human consumption, navigation, and agricultural and electricity production; (b) defining crop variety and calendars for food production; and (c) diversifying energy production with alternatives to hydropower. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Atmosphere
The land surface is an important component of numerical weather and climate forecast models due t... more The land surface is an important component of numerical weather and climate forecast models due to their effect on energy–water balances and fluxes, and it is essential for forecasts on a seasonal scale. The present study aimed to understand the effects of land surface processes on initialization of seasonal forecasts in the austral spring, in particular soil moisture. We built forecasts with the Brazilian global Atmospheric Model hindcast from 2000 to 2010, with a configuration similar to those used in the operational environment. To improve it, we developed a new initial condition of the land surface using the Land Information System over South America and the Global Land Data Assimilation System for the rest of the globe and used it as the input in the forecast model. The results demonstrated that the model is sensitive to changes in soil moisture and that the new high–resolution soil moisture dataset can be used in model initialization, which resulted in an increase in the corre...
International Journal of Climatology
Remote Sensing
In this work, we report the ongoing implementation of online-coupled aerosol–cloud microphysical–... more In this work, we report the ongoing implementation of online-coupled aerosol–cloud microphysical–radiation interactions in the Brazilian global atmospheric model (BAM) and evaluate the initial results, using remote-sensing data for JFM 2014 and JAS 2019. Rather than developing a new aerosol model, which incurs significant overheads in terms of fundamental research and workforce, a simplified aerosol module from a preexisting global aerosol–chemistry–climate model is adopted. The aerosol module is based on a modal representation and comprises a suite of aerosol microphysical processes. Mass and number mixing ratios, along with dry and wet radii, are predicted for black carbon, particulate organic matter, secondary organic aerosols, sulfate, dust, and sea salt aerosols. The module is extended further to include physically based parameterization for aerosol activation, vertical mixing, ice nucleation, and radiative optical properties computations. The simulated spatial patterns of surf...
Climate Resilience and Sustainability, 2022
The Climate Science for Service Partnership Brazil (CSSP-Brazil) project provides Brazil and UK p... more The Climate Science for Service Partnership Brazil (CSSP-Brazil) project provides Brazil and UK partners the opportunity to address important challenges faced by the climate modeling community, including the need to develop subseasonal and seasonal prediction and climate projection services. This paper provides an overview of the climate modeling and prediction research conducted through CSSP-Brazil within the context of a framework to advance climate prediction services in Brazil that includes a research-to-services (R2S) and a services-toresearch (S2R) feedback pathway. The paper also highlights plans to advance scientific understanding and capability to produce beneficial climate knowledge and new products to improve climate prediction services to support decisions in various industries in Brazil. Policy-relevant outcomes from climate modeling and prediction exercises illustrated in this paper include supporting stakeholders with climate information provided from weeks to months ahead for (a) improving water management strategies for human consumption, navigation, and agricultural and electricity production; (b) defining crop variety and calendars for food production; and (c) diversifying energy production with alternatives to hydropower. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Journal of Hydrometeorology, 2021
In South America, land–atmosphere interactions have an important impact on climate, particularly ... more In South America, land–atmosphere interactions have an important impact on climate, particularly the regional hydrological cycle, but detailed evaluation of these processes in global climate models has been limited. Focusing on the satellite-era period of 2003–14, we assess land–atmosphere interactions on annual to seasonal time scales over South America in satellite products, a novel reanalysis (ERA5-Land), and two global climate models: the Brazilian Global Atmospheric Model version 1.2 (BAM-1.2) and the U.K. Hadley Centre Global Environment Model version 3 (HadGEM3). We identify key features of South American land–atmosphere interactions represented in satellite and model datasets, including seasonal variation in coupling strength, large-scale spatial variation in the sensitivity of evapotranspiration to surface moisture, and a dipole in evaporative regime across the continent. Differences between products are also identified, with ERA5-Land, HadGEM3, and BAM-1.2 showing opposite...
Climate Resilience and Sustainability, 2021
This paper assesses how well the CPTEC/INPE Brazilian Global Atmospheric Model (BAM-1.2) and the ... more This paper assesses how well the CPTEC/INPE Brazilian Global Atmospheric Model (BAM-1.2) and the atmospheric component of the UK Met Office Hadley Centre Global Environment Model (HadGEM3-GC3.1) represent the main South American monsoon features. Climatological (1981-2010) ensemble means of Atmospheric Model Intercomparison Project (AMIP)-type climate simulations are evaluated. The assessment evaluated the models' ability to represent the South America austral summer and winter precipitation contrast and associated circulation, key South American monsoon system elements, the association between southeast Brazil and South America precipitation, and climatological (1997/1998 to 2013/2014) distributions of rainy season onset and demise dates over southeast Brazil (15 • S-25 • S, 40 • W-50 • W) and the core monsoon region (10 • S-20 • S, 45 • W-55 • W). Despite some identified deficiencies, both models depict the monsoon region and represent the main features, including (1) the northwest south east precipitation band and associated ascending motion over central South America; (2) the upper-level Bolivian High and the northeast South America trough during the summer; (3) the lower-level South Atlantic and Pacific subtropical anticyclones and (4) the low-level jet east of the Andes. Both models represent upper-level divergence and lower-level convergence over the This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Climate Dynamics, 2020
This paper presents an evaluation of climate simulations produced by the Brazilian Global Atmosph... more This paper presents an evaluation of climate simulations produced by the Brazilian Global Atmospheric Model version 1.2 (BAM-1.2) of the Center for Weather Forecast and Climate Studies (CPTEC). The model was run over the 1975–2017 period at two spatial resolutions, corresponding to ~ 180 and ~ 100 km, both with 42 vertical levels, following most of the Atmospheric Model Intercomparison Project (AMIP) protocol. In this protocol, observed sea surface temperatures (SSTs) are used as boundary conditions for the atmospheric model. Four ensemble members were run for each of the two resolutions. A series of diagnostics was computed for assessing the model’s ability to represent the top of the atmosphere (TOA) radiation, atmospheric temperature, circulation and precipitation climatological features. The representation of precipitation interannual variability, El Niño-Southern Oscillation (ENSO) precipitation teleconnections, the Madden and Julian Oscillation (MJO) and daily precipitation characteristics was also assessed. The model at both resolutions reproduced many observed temperature, atmospheric circulation and precipitation climatological features, despite several identified biases. The model atmosphere was found to be more transparent than the observations, leading to misrepresentation of cloud-radiation interactions. The net cloud radiative forcing, which produces a cooling effect on the global mean climate at the TOA, was well represented by the model. This was found to be due to the compensation between both weaker longwave cloud radiative forcing (LWCRF) and shortwave cloud radiative forcing (SWCRF) in the model compared to the observations. The model capability to represent inter-annual precipitation variability at both resolutions was found to be linked to the adequate representation of ENSO teleconnections. However, the model produced weaker than observed convective activity associated with the MJO. Light daily precipitation over the southeast of South America and other climatologically similar regions was diagnosed to be overestimated, and heavy daily precipitation underestimated by the model. Increasing spatial resolution helped to slightly reduce some of the diagnosed biases. The performed evaluation identified model aspects that need to be improved. These include the representation of polar continental surface and sea ice albedo, stratospheric ozone, low marine clouds, and daily precipitation features, which were found to be larger and last longer than the observed features.
Atmosphere, 2022
Dynamic numerical models of the atmosphere are the main tools used for weather and climate foreca... more Dynamic numerical models of the atmosphere are the main tools used for weather and climate forecasting as well as climate projections. Thus, this work evaluated the systematic errors and areas with large uncertainties in precipitation over the South American continent (SAC) based on regional climate simulations with the weather research and forecasting (WRF) model. Ten simulations using different convective, radiation, and microphysical schemes, and an ensemble mean among them, were performed with a resolution of 50 km, covering the CORDEX-South America domain. First, the seasonal precipitation variability and its differences were discussed. Then, its annual cycle was investigated through nine sub-domains on the SAC (AMZN, AMZS, NEBN, NEBS, SE, SURU, CHAC, PEQU, and TOTL). The Taylor Diagrams were used to assess the sensitivity of the model to different parameterizations and its ability to reproduce the simulated precipitation patterns. The results showed that the WRF simulations we...
Estudos Interdisciplinares nas Ciências Exatas e da Terra e Engenharias 4, Sep 11, 2019
O conteúdo dos artigos e seus dados em sua forma, correção e confiabilidade são de responsabilida... more O conteúdo dos artigos e seus dados em sua forma, correção e confiabilidade são de responsabilidade exclusiva dos autores. Permitido o download da obra e o compartilhamento desde que sejam atribuídos créditos aos autores, mas sem a possibilidade de alterá-la de nenhuma forma ou utilizá-la para fins comerciais. Conselho Editorial Ciências Humanas e Sociais Aplicadas Estudos Interdisciplinares nas Ciências Exatas e da Terra e Engenharias 4 Capítulo 1
Geoscientific Model Development
The main features of climate change patterns, as simulated by the coupled ocean-atmosphere versio... more The main features of climate change patterns, as simulated by the coupled ocean-atmosphere version 2.5 of the Brazilian Earth System Model (BESM), are compared with those of 25 other CMIP5 models, focusing on temperature, precipitation, atmospheric circulation, and radiative feedbacks. The climate sensitivity to quadrupling the atmospheric CO 2 concentration was investigated via two methods: linear regression and radiative kernels . Radiative kernels from both the National Center for Atmospheric Research (NCAR) and the Geophysical Fluid Dynamics Laboratory (GFDL) were used to decompose the climate feedback responses of the CMIP5 models and BESM into different processes. By applying the linear regression method for equilibrium climate sensitivity (ECS) estimation, we obtained a BESM value close to the ensemble mean value. This study reveals that the BESM simulations yield zonally average feedbacks, as estimated from radiative kernels, that lie within the ensemble standard deviation. Exceptions were found in the high latitudes of the Northern Hemisphere and over the ocean near Antarctica, where BESM showed values for lapse rate, humidity feedback, and albedo that were marginally outside the standard deviation of the values from the CMIP5 multi-model ensemble. For those areas, BESM also featured a strong positive cloud feedback that appeared as an outlier compared with all analyzed models. However, BESM showed physically consistent changes in the temperature, precipitation, and atmospheric circulation patterns relative to the CMIP5 ensemble mean.
The focus of this study was to measure the Volatile Organic Compounds (VOCs) concentrations in th... more The focus of this study was to measure the Volatile Organic Compounds (VOCs) concentrations in the megacity – Sao Paulo Metropolitan Area (SPMA). The measurements analyzed in this study included 78 hydrocarbon (HC) samples collected during 2006, and 66 samples of HC, 62 of aldehydes and 42 of ethanol collected during 2011-2012. The observational results showed that the consumption of ethanol, gasoline and diesel from 2006 to 2012 increased by 64 %, 23 % and 25 %, respectively, with substantial changes in the atmospheric composition. The 10 most abundant VOCs in the atmosphere found during 2011/2012 at CETESB IPEN/USP air quality monitoring station were ethanol, acetaldehyde, formaldehyde, acetone, propane, ethene, ethane, butane, 1-ethyl-4-methyl benzene, and 1,2,4-trimethyl benzene. During the 2006 campaign, alkanes represented 54.8 % of the total HC concentration, alkenes 29.2 %, aromatics 13.6 %, and alkadienes 2.4 %. On the other hand, during the 2011-2012 campaign, aldehydes re...
Uploads
Papers by Silvio Nilo Figueroa