Dinámica de Fluidos Geofísicos Computacional
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Item Open Access Impacto de la resolución espacial en la dinámica del Pacífico Tropical Este bajo condiciones normales(Instituto Geofísico del Perú, 2016-12) Campos, Fernando; Montes Torres, IvonneLos remolinos de mesoescala son estructuras cuasi-circulares con radios menores a 250 km (Chaigneau et al., 2009), con extensión vertical máxima de 1000 metros (Oey et al., 2005) y un tiempo de vida desde días hasta virtualmente permanentes (estacionarios). Estos juegan un rol importante en el transporte horizontal y vertical de grandes cantidades de calor, momento y trazadores biogeoquímicos desde su zona de formación hacia regiones lejanas a la costa contribuyendo así en la mezcla lenta de las masas de agua oceánicas (Carton, 2010; Klein y Lapeyre, 2009). Sus mecanismos de generación son muy variados dependiendo de la ubicación geográfca, en las regiones de frontera oriental generalmente son debido a las inestabilidades en las corrientes costeras, fuerte afloramiento y variabilidad estacional e intra-estacional de los flujos costeros (Pizarro et al., 2002). […] el objetivo de este trabajo es documentar el impacto de la resolución espacial sobre la dinámica del Pacífico Tropical Este y en los mecanismos físicos asociados a la actividad de mesoescala. Para ello se emplearon dos simulaciones climatológicas anuales del modelo ROMS, las cuales son idénticas en cuanto al dominio, forzantes, condiciones iniciales y de fronteras, diferenciándose en las resoluciones horizontales usadas de 1/6° y de 1/9°. El dominio es 3°N a 20°S y 70°O a 90°O, cubriendo 32 niveles en la vertical (Montes et al., 2010; 2014).Item Open Access Diseño del Sistema HPC-Linux-Clúster del IGP(Instituto Geofísico del Perú, 2017-03) Santillán, Oscar; Gilt, Huber; Ingunza, Augusto; Mosquera Vásquez, Kobi Alberto; Montes Torres, IvonneEn este artículo se presentan algunas características y pautas que fueron seguidas para la implementación de la infraestructura computacional de alto rendimiento denominado HPC-Linux-Clúster, el cual se encuentra a disposición de la comunidad científica y académica del país.Item Open Access Sistema computacional de alto rendimiento para la simulación de fluidos geofísicos HPC-Linux-Clúster(Instituto Geofísico del Perú, 2016-03) Montes Torres, Ivonne; Mosquera Vásquez, Kobi Alberto; Luna, Maria Rosa; Gilt, Huber; Gazen, Didier; Woodman Pollitt, Ronald FranciscoExplica acerca del sistema computacional HPC-Linux-Clúster adquirido por el Instituto Geofísico del Perú (IGP), el cual es de vital importancia para contribuir al desarrollo científico y tecnológico del Perú. Esta infraestructura proporciona datos sobre los recursos computacionales requeridos para realizar investigaciones científicas de alto nivel que se desarrollan en el IGP. Además, el HPC-Linux-Clúster se presenta como la infraestructura de última generación capaz de suplir la necesidad computacional de las investigaciones dedicadas a resolver y analizar problemas geofísicos (naturales y antropogénicos) que afectan a la población peruana y sus actividades, así como incrementar la capacidad de pronóstico y contribuir con el proceso de toma de decisiones que permita establecer estrategias para reducir la vulnerabilidad actual en el Perú.Item Open Access Variabilidad intraestacional a lo largo de la costa peruana(Instituto Geofísico del Perú, 2016-04) Prieto, Eva; Mosquera Vásquez, Kobi Alberto; Montes Torres, IvonneUno de los principales factores que estarían modulando la dinámica costera de Perú es la propagación de ondas de Kelvin ecuatoriales (Dewitte et al., 2008; Mosquera-Vasquez et al., 2013; 2014), perturbaciones oceánicas atrapadas alrededor de la línea ecuatorial. Sin embargo, además de las ondas Kelvin se considera necesario tener en cuenta otros factores como los vientos y la coexistencia de ondas de Rossby y de remolinos de mesoescala en la región para conocer el origen de esta variabilidad intraestacional.Item Open Access Impacto de la resolución horizontal de un modelo regional sobre el afloramiento costero frente a Perú(Instituto Geofísico del Perú, 2014-12) Montes Torres, Ivonne; Fajardo Urbina, Jeancarlo Manuel; Ramos, Yakelyn; Saavedra Huanca, Miguel; Aparco Lara, Jonathan; Segura Cajachagua, Hans Mikhail; Hurtado, P.; Mosquera Vásquez, Kobi Alberto; Takahashi, KenEl propósito de este trabajo es estudiar y entender la dinámica del afloramiento costero bajo condiciones promedio usando del modelo numérico de alta resolución ROMS. Dicho modelo es configurado usando dos diferentes resoluciones espaciales (i.e., dos tamaños de grilla diferentes) y aplicando las mismas condiciones iniciales y de frontera a fin de entender las consideraciones dinámicas que se deben tomar en cuenta para modelar la dinámica del afloramiento costero durante las diferentes fases de El Niño – Oscilación del Sur (ENSO).Item Open Access Evolución del Sistema Computacional de Alto Rendimiento en el IGP para un mejor pronóstico y estudio de los fenómenos climáticos(Instituto Geofísico del Perú, 2014-11) Segura Curi, Berlín Aveles; Montes Torres, Ivonne; Mosquera Vásquez, Kobi AlbertoEn la actualidad, a nivel mundial, el desarrollo y empleo de modelos numéricos implica el uso de supercomputadores y/o computadoras de alto rendimiento para resolver problemas que involucren la dinámica de la Tierra, su interacción con los seres vivos, los procesos naturales que pueden afectar al ser humano y el efecto de este sobre los procesos físicos naturales en diferentes escalas de espacio y tiempo (e.g., sobre todo el planeta o una región en particular y, además, en el pasado, presente o futuro). El Instituto Geofísico del Perú (IGP), por medio del área de Variabilidad y Cambio Climático, no ha estado alejado de esta línea técnica, ya que desde inicios del año 1998 ha venido utilizando, de manera permanente, tecnología de última generación para el desarrollo y aplicación de modelos numéricos que contribuyan a comprender mejor la física de la atmósfera y el océano, a fin de desarrollar su capacidad de pronóstico en temas que son cruciales para el Perú como, por ejemplo, el Fenómeno El Niño.Item Restricted Response of the WRF model to different resolutions in the rainfall forecast over the complex Peruvian orography(Springer Nature, 2019-08-01) Moya Álvarez, Aldo Saturnino; Martínez Castro, Daniel; Kumar, Shailendra; Estevan, René; Silva Vidal, YaminaThe main objective of the research is to evaluate the response of the WRF model to the domains and resolutions that are used in complex orographic conditions like the central Andes of Peru for the forecast of short- and medium-term rainfall. To do this, the model was configured with four domains and the verifications were made using data from meteorological stations located within the study area and TRMMdata. Experiments were conducted for nine 10-day periods of rainy days, five cases of extreme rainfall, and one event with hail fall on the region. In general, the model overestimates precipitation, but, in the five cases of extreme rainfall, and in the case of the hailstorm, underestimation was observed, so it is not accurate to assert in an absolute way thatWRF overestimates precipitation in the study region. It was observed that the 3-km domain simulate effectively the accumulated rainfall, while the 0.75-km domain reproduces better the process at local scale. The results in the domain with the coarsest resolution of 18 km showed the lowest skill in simulating rainfall compared to the higher resolutions. Thus, it is concluded that an increase of resolution leads to an improvement of the results of rainfall forecast in the region and the structure of clouds systems. At the same time, the domains with resolutions of 18 km showed poorer results.Item Open Access Extreme Rainfall Forecast with the WRF-ARW Model in the Central Andes of Peru(MDPI, 2018-09-18) Moya Álvarez, Aldo Saturnino; Gálvez, José; Holguín, Andrea; Estevan, René; Kumar, Shailendra; Villalobos Puma, Elver Edmundo; Martínez Castro, Daniel; Silva Vidal, YaminaThe ability of the WRF-ARW (Weather Research and Forecasting-Advanced Research WRF) model to forecast extreme rainfall in the Central Andes of Peru is evaluated in this study, using observations from stations located in the Mantaro basin and GOES (Geostationary Operational Environmental Satellite) images. The evaluation analyzes the synoptic conditions averaged over 40 extreme event cases, and considers model simulations organized in 4 nested domains. We first establish that atypical events in the region are those with more than 27 mm of rainfall per day when averaging over all the stations. More than 50% of the selected cases occurred during January, February, and April, with the most extreme occurring during February. The average synoptic conditions show negative geopotential anomalies and positive humidity anomalies in 700 and 500 hPa. At 200 hPa, the subtropical upper ridge or “Bolivian high” was present, with its northern divergent flank over the Mantaro basin. Simulation results show that the Weather Research and Forecasting (WRF) model underestimates rainfall totals in approximately 50–60% of cases, mainly in the south of the basin and in the extreme west along the mountain range. The analysis of two case studies shows that the underestimation by the model is probably due to three reasons: inability to generate convection in the upstream Amazon during early morning hours, apparently related to processes of larger scales; limitations on describing mesoscale processes that lead to vertical movements capable of producing extreme rainfall; and limitations on the microphysics scheme to generate heavy rainfall.Item Open Access The vertical structure of the eastern Pacific ITCZs and associated circulation using the TRMM Precipitation Radar and in situ data(American Geophysical Union (AGU), 2016-08-16) Huaman, L.; Takahashi, KenThe atmospheric circulation associated with the eastern Pacific single and double ITCZs, particularly its vertical structure, is little known due to the sparce observations. Using precipitation profiles from the Tropical Rainfall Measure Mission (TRMM) Precipitation Radar, with approximations to the liquid water and energy budget equations, we estimated vertical profiles of latent heating and vertical velocity in the far eastern Pacific (95°W–85°W) ITCZs in the 800–730 hPa layer. We combined this with Eastern Pacific Investigation of Climate campaign (EPIC2001) and other in situ data to produce a preliminary characterization of the meridional‐vertical circulation. We found evidence of a double‐cell structure in boreal fall between the ITCZ and the equator, with both shallow and upper level peaks in vertical velocity. In spring, the flow poleward of the two ITCZs has a single‐cell structure, although around the equator it shows some hints of the double cells. Reanalysis and satellite‐based data are shown to be unreliable for describing the vertical structure of the circulation.Item Open Access Sensitivity study on the influence of parameterization schemes in WRF_ARW model on short- and medium-range precipitation forecasts in the Central Andes of Peru(Hindawi, 2018-05-22) Moya Álvarez, Aldo Saturnino; Martínez Castro, Daniel; Flores Rojas, José Luis; Silva Vidal, YaminaA sensitivity study of the performance of the Weather Research and Forecasting regional model (WRF, version 3.7) to the use of different microphysics, cumulus, and boundary layer parameterizations for short- and medium-term precipitation forecast is conducted in the Central Andes of Peru. Lin-Purdué, Thompson, and Morrison microphysics schemes were tested, as well as the Grell–Freitas, Grell 3d, and Betts–Miller–Janjic cumulus parameterizations. The tested boundary layer schemes were the Yonsei University and Mellor–Yamada–Janjic. A control configuration was defined, using the Thompson, Grell–Freitas, and Yonsei University schemes, and a set of numerical experiments is made, using different combinations of parameterizations. Data from 19 local meteorological stations and regional and global gridded were used for verification. It was concluded that all the configurations overestimate precipitation, but the one using the Morrison microphysical scheme had the best performance, based on the indicators of bias () and root mean square error (RMSE). It is recommended not to use the Betts–Miller–Janjic scheme in this region for low resolution domains. Categorical forecast verification of the occurrence of rainfall as a binary variable showed detection rates higher than 85%. According to this criterion, the best performing configuration was the combination of Betts–Miller–Janjic and Morrison. Spatial verification showed that, even if all the configurations overestimated precipitation in some degree, spatial patterns of rainfall match the TRMM and PISCO rainfall data. Morrison’s microphysics scheme shows the best results, and consequently, this configuration is recommended for short- and medium-term rainfall forecasting tasks in the Central Andes of Peru and particularly in the Mantaro basin. The results of a special sensitivity experiment showed that the activation or not of cumulus parametrization for the domain of 3 km resolution is not relevant for the precipitation forecast in the study region.Item Restricted Impacts of different ENSO flavors and tropical Pacific convection variability (ITCZ, SPCZ) on austral summer rainfall in South America, with a focus on Peru(Royal Meteorological Society, 2018-01) Sulca Jota, Juan Carlos; Takahashi, Ken; Espinoza, Jhan Carlo; Vuille, Mathias; Lavado-Casimiro, WaldoEl Niño in the eastern and central Pacific has different impacts on the rainfall of South America, and the atmospheric pathways through the South Pacific Convergence Zone (SPCZ) and Inter‐Tropical Convergence Zone (ITCZ) are poorly understood. To address this, we performed linear regression analysis of E (eastern Pacific) and C (central Pacific) indices of sea surface temperature (SST), as well as precipitation indices for the SPCZ and ITCZ, with gridded precipitation and reanalysis data sets during the austral summer (December–February) for the 1980–2016 period. Positive C induces dry anomalies along the tropical Andes and northern South America (NSA), while wet anomalies prevail over southeastern South America (SESA). Moreover, it produces wet conditions in the northwestern Peruvian Amazon. In contrast, positive E enhances wet conditions along the coasts of Ecuador and northern Peru associated with the southward displacement of the eastern Pacific ITCZ and induces dry conditions in Altiplano, Amazon basin, and northeastern Brazil (NEB). Both El Niño Southern Oscillation (ENSO) indices are associated with weakened upper‐level easterly flow over Peru, but it is more restricted to the central and southern Peruvian Andes with positive E. Both SPCZ indices, the zonal position of the SPCZ and its latitudinal displacement, suppress rainfall along western Peruvian Andes when are positive, but the latter also inhibits rainfall over the Bolivian Altiplano. They are also linked to upper‐level westerly wind anomalies overall of Peru, but these anomalies do not extend as far south in the first. The southward displacement of the eastern Pacific ITCZ also induces wet anomalies in SESA while dry anomalies prevail over NEB, the western Amazon basin, and Bolivia. Oppositely, the southward displacement of the central Pacific ITCZ induces dry anomalies in NEB and along the northern coast of Peru; while wet anomalies occur mainly in eastern Brazil, Paraguay, and Bolivia through an enhancement of the low level jet.