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Excessive rain may cause several problems for society. Understanding the behaviour of extreme rainfall and quantifying it in an assertive manner is important for whole society. The purpose of this work is to evaluate the ability of satellite precipitation products to detect the extreme rainfall over different regions of Brazil. The products evaluated in this investigation were from Frequent Rainfall Observations on GridS (FROGS) database. The results show that, each region of Brazil is characterized by extremes of rain with different intensities. The regions that presented the highest values are south and north regions of Brazil with values around 125.0 mm/day. In both regions, the GSMAP product (with rain gauges adjustments) have better performance, as shown in the metrics for the south and north regions where bias = −1.20 mm/day and −6.49 mm/day; r = 0.65 and 0.50; std = 10.15 mm/day and 10.63 mm/day; rmse = 9.58 mm/day and 13.16 mm/day respectively. On the other hand, the regions with the lowest intensities are the northeastern region, inland and coast, presented frequent extreme values of approximately 35.0 mm/day. At these regions, both versions of product 3B42RT v7.0 demonstrated a better performance, as demonstrated in the metrics for inland and coast northeastern regions, bias = 2.82 mm/day and −2.94 mm/day; r = 0.18 and 0.30; std = 8.53 mm/day and 6.97 mm/day; rmse = 14.75 mm/day and 7.03 mm/day, respectively. It is worth mentioning that the precipitation values found in this work do not necessarily cause disasters or generate impacts in the analyzed regions, they were considered extreme from a statistical point of view, considering the analyzed database.
Rayana Santos Araujo Palharini; Daniel Alejandro Vila; Daniele Torres Rodrigues; Rodrigo Cassinelli Palharini; Enrique Vieira Mattos; George Ulguim Pedra. Assessment of extreme rainfall estimates from satellite-based: Regional analysis. Remote Sensing Applications: Society and Environment 2021, 23, 100603 .
AMA StyleRayana Santos Araujo Palharini, Daniel Alejandro Vila, Daniele Torres Rodrigues, Rodrigo Cassinelli Palharini, Enrique Vieira Mattos, George Ulguim Pedra. Assessment of extreme rainfall estimates from satellite-based: Regional analysis. Remote Sensing Applications: Society and Environment. 2021; 23 ():100603.
Chicago/Turabian StyleRayana Santos Araujo Palharini; Daniel Alejandro Vila; Daniele Torres Rodrigues; Rodrigo Cassinelli Palharini; Enrique Vieira Mattos; George Ulguim Pedra. 2021. "Assessment of extreme rainfall estimates from satellite-based: Regional analysis." Remote Sensing Applications: Society and Environment 23, no. : 100603.
In developing countries, accurate rainfall estimation with adequate spatial distribution is limited due to sparse rain gauge networks. One way to solve this problem is the use of satellite-based precipitation products. These satellite products have significant spatial coverage of rainfall estimates and it is of fundamental importance to investigate their performance across space–time scales and the factors that affect their uncertainties. In the open literature, some studies have already analyzed the ability of satellite-based rain estimation products to estimate average rainfall values. These investigations have found very close agreement between the estimates and observed data. However, further evaluation of the satellite precipitation products is necessary to improve their reliability to estimate extreme values. In this scenario, the main goal of this work is to evaluate the ability of satellite-based precipitation products to capture the characteristics of extreme precipitation over the tropical region of South America. The products evaluated in this investigation were 3B42 RT v7.0, 3B42 RT v7.0 uncalibrated, CMORPH V1.0 RAW, CMORPH V1.0 CRT, GSMAP-NRT-no gauge v6.0, GSMAP-NRT- gauge v6.0, CHIRP V2.0, CHIRPS V2.0, PERSIANN CDR v1 r1, CoSch and TAPEER v1.5 from Frequent Rainfall Observations on GridS (FROGS) database. Some products considered in this investigation are adjusted with rain gauge values and others only with satellite information. In this study, these two sets of products were considered. In addition, gauge-based daily precipitation data, provided by Brazil’s National Institute for Space Research, were used as reference in the analyses. In order to compare gauge-based daily precipitation and satellite-based data for extreme values, statistical techniques were used to evaluate the performance the selected satellite products over the tropical region of South America. According to the results, the threshold for rain to be considered an extreme event in South America presented high variability, ranging from 20 to 150 mm/day, depending on the region and the percentile threshold chosen for analysis. In addition, the results showed that the ability of the satellite estimates to retrieve rainfall extremes depends on the geographical location and large-scale rainfall regimes.
Rayana Palharini; Daniel Vila; Daniele Rodrigues; David Quispe; Rodrigo Palharini; Ricardo Siqueira; João Afonso. Assessment of the Extreme Precipitation by Satellite Estimates over South America. Remote Sensing 2020, 12, 2085 .
AMA StyleRayana Palharini, Daniel Vila, Daniele Rodrigues, David Quispe, Rodrigo Palharini, Ricardo Siqueira, João Afonso. Assessment of the Extreme Precipitation by Satellite Estimates over South America. Remote Sensing. 2020; 12 (13):2085.
Chicago/Turabian StyleRayana Palharini; Daniel Vila; Daniele Rodrigues; David Quispe; Rodrigo Palharini; Ricardo Siqueira; João Afonso. 2020. "Assessment of the Extreme Precipitation by Satellite Estimates over South America." Remote Sensing 12, no. 13: 2085.
A computational investigation has been carried out to examine a non-reacting rarefied hypersonic flow over cavities by employing the Direct Simulation Monte Carlo (DSMC) method. The work focuses on the effects on the aerodynamic surface quantities due to variations in the cavity length-to-depth (L/H) ratio. The results highlight the sensitivity of the heat transfer, pressure and skin friction coefficients due to changes to the cavity L/H ratio. The L/H ratio ranged from 1 to 4, which corresponds to the transition flow regime based on an overall Knudsen number KnL. The analysis showed that the aerodynamic quantities acting on the cavity surface rely on the L/H ratio. It was found that pressure load and heating load to the cavity surfaces presented peak values along the forward face, more precisely in the vicinity of the cavity shoulder. Moreover, these loads are much higher than those found in a smooth surface, for the conditions investigated.
Rodrigo C. Palharini; Wilson F.N. Santos. The impact of the length-to-depth ratio on aerodynamic surface quantities of a rarefied hypersonic cavity flow. Aerospace Science and Technology 2019, 88, 110 -125.
AMA StyleRodrigo C. Palharini, Wilson F.N. Santos. The impact of the length-to-depth ratio on aerodynamic surface quantities of a rarefied hypersonic cavity flow. Aerospace Science and Technology. 2019; 88 ():110-125.
Chicago/Turabian StyleRodrigo C. Palharini; Wilson F.N. Santos. 2019. "The impact of the length-to-depth ratio on aerodynamic surface quantities of a rarefied hypersonic cavity flow." Aerospace Science and Technology 88, no. : 110-125.
Rodrigo C. Palharini; Joao Luiz F. Azevedo; Craig White. DSMC Computations of SARA Reentry Capsule Exposed to Weakly Ionized Gas Flow. AIAA Scitech 2019 Forum 2019, 1 .
AMA StyleRodrigo C. Palharini, Joao Luiz F. Azevedo, Craig White. DSMC Computations of SARA Reentry Capsule Exposed to Weakly Ionized Gas Flow. AIAA Scitech 2019 Forum. 2019; ():1.
Chicago/Turabian StyleRodrigo C. Palharini; Joao Luiz F. Azevedo; Craig White. 2019. "DSMC Computations of SARA Reentry Capsule Exposed to Weakly Ionized Gas Flow." AIAA Scitech 2019 Forum , no. : 1.
Rodrigo C. Palharini; Thomas J. Scanlon; Craig White. Chemically reacting hypersonic flows over 3D cavities: Flowfield structure characterisation. Computers & Fluids 2018, 165, 173 -187.
AMA StyleRodrigo C. Palharini, Thomas J. Scanlon, Craig White. Chemically reacting hypersonic flows over 3D cavities: Flowfield structure characterisation. Computers & Fluids. 2018; 165 ():173-187.
Chicago/Turabian StyleRodrigo C. Palharini; Thomas J. Scanlon; Craig White. 2018. "Chemically reacting hypersonic flows over 3D cavities: Flowfield structure characterisation." Computers & Fluids 165, no. : 173-187.
Rodrigo C. Palharini; João Luiz F. Azevedo. Thermochemical Nonequilibrium Computations of a Brazilian Reentry Satellite. Journal of Spacecraft and Rockets 2017, 54, 961 -966.
AMA StyleRodrigo C. Palharini, João Luiz F. Azevedo. Thermochemical Nonequilibrium Computations of a Brazilian Reentry Satellite. Journal of Spacecraft and Rockets. 2017; 54 (4):961-966.
Chicago/Turabian StyleRodrigo C. Palharini; João Luiz F. Azevedo. 2017. "Thermochemical Nonequilibrium Computations of a Brazilian Reentry Satellite." Journal of Spacecraft and Rockets 54, no. 4: 961-966.
A two-temperature CFD (computational fluid dynamics) solver is a prerequisite to any spacecraft re-entry numerical study that aims at producing results with a satisfactory level of accuracy within realistic timescales. In this respect, a new two-temperature CFD solver, hy2Foam, has been developed within the framework of the open-source CFD platform OpenFOAM for the prediction of hypersonic reacting flows. This solver makes the distinct juncture between the trans-rotational and multiple vibrational-electronic temperatures. hy2Foam has the capability to model vibrational-translational and vibrational-vibrational energy exchanges in an eleven-species air mixture. It makes use of either the Park TTv model or the coupled vibration-dissociation-vibration (CVDV) model to handle chemistry-vibration coupling and it can simulate flows with or without electronic energy. Verification of the code for various zero-dimensional adiabatic heat baths of progressive complexity has been carried out. hy2Foam has been shown to produce results in good agreement with those given by the CFD code LeMANS (The Michigan Aerothermodynamic Navier-Stokes solver) and previously published data. A comparison is also performed with the open-source DSMC (direct simulation Monte Carlo) code dsmcFoam. It has been demonstrated that the use of the CVDV model and rates derived from Quantum-Kinetic theory promote a satisfactory consistency between the CFD and DSMC chemistry modules.
Vincent Casseau; Rodrigo C. Palharini; Thomas J. Scanlon; Richard E. Brown. A Two-Temperature Open-Source CFD Model for Hypersonic Reacting Flows, Part One: Zero-Dimensional Analysis. Aerospace 2016, 3, 34 .
AMA StyleVincent Casseau, Rodrigo C. Palharini, Thomas J. Scanlon, Richard E. Brown. A Two-Temperature Open-Source CFD Model for Hypersonic Reacting Flows, Part One: Zero-Dimensional Analysis. Aerospace. 2016; 3 (4):34.
Chicago/Turabian StyleVincent Casseau; Rodrigo C. Palharini; Thomas J. Scanlon; Richard E. Brown. 2016. "A Two-Temperature Open-Source CFD Model for Hypersonic Reacting Flows, Part One: Zero-Dimensional Analysis." Aerospace 3, no. 4: 34.
Rodrigo C. Palharini; Craig White; Thomas J. Scanlon; Richard E. Brown; Matthew K. Borg; Jason Reese. Benchmark numerical simulations of rarefied non-reacting gas flows using an open-source DSMC code. Computers & Fluids 2015, 120, 140 -157.
AMA StyleRodrigo C. Palharini, Craig White, Thomas J. Scanlon, Richard E. Brown, Matthew K. Borg, Jason Reese. Benchmark numerical simulations of rarefied non-reacting gas flows using an open-source DSMC code. Computers & Fluids. 2015; 120 ():140-157.
Chicago/Turabian StyleRodrigo C. Palharini; Craig White; Thomas J. Scanlon; Richard E. Brown; Matthew K. Borg; Jason Reese. 2015. "Benchmark numerical simulations of rarefied non-reacting gas flows using an open-source DSMC code." Computers & Fluids 120, no. : 140-157.
An open-source implementation of chemistry modeling for the direct simulation Monte Carlo method is presented. Following the recent work of Bird (Bird, G. A., , “The Q-K Model for Gas Phase Chemical Reaction Rates,” Physics of Fluids, Vol. 23, No. 10, 2011, Paper 106101), an approach known as the quantum-kinetic method has been adopted to describe chemical reactions in a five-species air model using direct simulation Monte Carlo procedures based on microscopic gas information. The quantum-kinetic technique has been implemented within the framework of the dsmcFoam code, a derivative of the open-source computational-fluid-dynamics code OpenFOAM. Results for vibrational relaxation, dissociation, and exchange reaction rates for an adiabatic bath demonstrate the success of the quantum-kinetic model implementation in dsmcFoam when compared with analytical solutions for both inert and reacting conditions. A comparison is also made between the quantum-kinetic and total collision energy chemistry approaches for a hypersonic flow benchmark case.
Thomas J. Scanlon; Craig White; Matthew K. Borg; Rodrigo Cassineli Palharini; Erin Farbar; Iain D. Boyd; Jason Reese; Richard E. Brown. Open-Source Direct Simulation Monte Carlo Chemistry Modeling for Hypersonic Flows. AIAA Journal 2015, 53, 1670 -1680.
AMA StyleThomas J. Scanlon, Craig White, Matthew K. Borg, Rodrigo Cassineli Palharini, Erin Farbar, Iain D. Boyd, Jason Reese, Richard E. Brown. Open-Source Direct Simulation Monte Carlo Chemistry Modeling for Hypersonic Flows. AIAA Journal. 2015; 53 (6):1670-1680.
Chicago/Turabian StyleThomas J. Scanlon; Craig White; Matthew K. Borg; Rodrigo Cassineli Palharini; Erin Farbar; Iain D. Boyd; Jason Reese; Richard E. Brown. 2015. "Open-Source Direct Simulation Monte Carlo Chemistry Modeling for Hypersonic Flows." AIAA Journal 53, no. 6: 1670-1680.
Rodrigo Cassineli Palharini; T. J. Scanlon; J. M. Reese. Effects of Angle of Attack on the Behaviour of Imperfections in Thermal Protection Systems of Re-entry Vehicles. 29th International Symposium on Shock Waves 1 2015, 551 -556.
AMA StyleRodrigo Cassineli Palharini, T. J. Scanlon, J. M. Reese. Effects of Angle of Attack on the Behaviour of Imperfections in Thermal Protection Systems of Re-entry Vehicles. 29th International Symposium on Shock Waves 1. 2015; ():551-556.
Chicago/Turabian StyleRodrigo Cassineli Palharini; T. J. Scanlon; J. M. Reese. 2015. "Effects of Angle of Attack on the Behaviour of Imperfections in Thermal Protection Systems of Re-entry Vehicles." 29th International Symposium on Shock Waves 1 , no. : 551-556.
The thermal protection system is a key element in atmospheric re-entry missions of aerospace vehicles. Usually, in the thermal load calculations, the analysis assumes that the vehicle has a smooth surface. However, discontinuities or imperfections are often present on the aerospace vehicle surfaces due to fabrication tolerances, sensor installations, spaces between the thermal protection plates, and differential expansion or ablation rates between non-similar materials. In the present work, rarefied hypersonic flows over two- and three-dimensional cavities at an altitude of 80 km in the Earth’s atmosphere are studied numerically. To model flows in the transitional regime, where the validity of the Navier–Stokes equations is questionable, the direct simulation Monte Carlo method has been used. The primary goal is to assess the sensitivity of heat transfer, pressure, and skin-friction coefficients for a family of two- and three-dimensional cavities defined by different length-to-depth ratios. The analysis shows that an assumption of two-dimensionality plays a key role in the overprediction of the aerodynamic properties. Previous work using a continuum approach shows that two recirculation regions and flow attachment occurs when the length-to-depth ratio is equal to 14; however, the same phenomena are observed in the transitional regime when the cavity length-to-depth ratio is equal to 4. A study of the influence of the cavity width has also been conducted. It is shown that increasing the cavity width results in an augmentation of the surface aerothermodynamic quantities.
Rodrigo Cassineli Palharini; Thomas J. Scanlon; Jason Reese. Aerothermodynamic Comparison of Two- and Three-Dimensional Rarefied Hypersonic Cavity Flows. Journal of Spacecraft and Rockets 2014, 51, 1619 -1630.
AMA StyleRodrigo Cassineli Palharini, Thomas J. Scanlon, Jason Reese. Aerothermodynamic Comparison of Two- and Three-Dimensional Rarefied Hypersonic Cavity Flows. Journal of Spacecraft and Rockets. 2014; 51 (5):1619-1630.
Chicago/Turabian StyleRodrigo Cassineli Palharini; Thomas J. Scanlon; Jason Reese. 2014. "Aerothermodynamic Comparison of Two- and Three-Dimensional Rarefied Hypersonic Cavity Flows." Journal of Spacecraft and Rockets 51, no. 5: 1619-1630.
Wilson Santos; Rodrigo Cassineli Palharini. Length-to-Depth Ratio Effects on Flowfield Structure of Low-Density Hypersonic Cavity Flow. 42nd AIAA Thermophysics Conference 2011, 1 .
AMA StyleWilson Santos, Rodrigo Cassineli Palharini. Length-to-Depth Ratio Effects on Flowfield Structure of Low-Density Hypersonic Cavity Flow. 42nd AIAA Thermophysics Conference. 2011; ():1.
Chicago/Turabian StyleWilson Santos; Rodrigo Cassineli Palharini. 2011. "Length-to-Depth Ratio Effects on Flowfield Structure of Low-Density Hypersonic Cavity Flow." 42nd AIAA Thermophysics Conference , no. : 1.