Browsing by Author "Estevan, René"
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Item Open Access Analysis of extreme meteorological events in the central Andes of Peru using a set of specialized instruments(MDPI, 2021-03-21) Flores Rojas, José Luis; Silva Vidal, Yamina; Suárez Salas, Luis; Estevan, René; Valdivia Prado, Jairo Michael; Saavedra Huanca, Miguel; Giráldez, Lucy; Piñas-Laura, Manuel; Scipión, Danny; Milla, Marco; Kumar, Shailendra; Martínez Castro, DanielA set of instruments to measure several physical, microphysical, and radiative properties of the atmosphere and clouds are essential to identify, understand and, subsequently, forecast and prevent the effects of extreme meteorological events, such as severe rainfall, hailstorms, frost events and high pollution events, that can occur with some regularity in the central Andes of Peru. However, like many other Latin American countries, Peru lacks an adequate network of meteorological stations to identify and analyze extreme meteorological events. To partially remedy this deficiency, the Geophysical Institute of Peru has installed a set of specialized sensors (LAMAR) on the Huancayo observatory (12.04º S, 75.32º W, 3350 m ASL), located in the Mantaro river basin, which is a part of the central Andes of Peru, especially in agricultural areas. LAMAR consists of a set of sensors that are used to measure the main atmosphere and soil variables located in a 30-meter-high tower. It also has a set of high-quality radiation sensors (BSRN station) that helps measure the components of short-wave (SW) (global, diffuse, direct and reflected) and long-wave (LW) (emitted and incident) irradiance mounted in a 6-meter-high tower. Moreover, to analyze the microphysics properties of clouds and rainfall, LAMAR includes a set of profiler radars: A Ka-band cloud profiler (MIRA-35c), a UHF wind profiler (CLAIRE), and a VHF wind profiler (BLTR), along with two disdrometers (PARSIVEL2) and two rain gauges pluviometers. The present study performs a detailed dynamic and energetic analysis of two extreme rainfall events, two intense frost events, and three high-pollution events occurring on the Huancayo observatory between 2018 and 2019...Item Open Access Caracterización temporal del espesor óptico de aerosoles y su relación con las infecciones respiratorias agudas(Instituto Geofísico del Perú, 2020-08) Gonzales Pérez, María Violeta; Estevan, RenéLos aerosoles son partículas sólidas o líquidas suspendidas en la atmósfera. Su alta concentración, así como determinados tipos de aerosoles, pueden causar daños a la salud humana. El objetivo de este trabajo es relacionar el Espesor Óptico de Aerosoles (EOA) con las infecciones respiratorias agudas (IRAs). El EOA es una medida de la dispersión y absorción de luz visible por las partículas de aerosoles en la columna vertical de la atmósfera. Este indicador en conjunto con el Exponente de Ångström (EA o α ) nos permiten caracterizar los aerosoles atmosféricos, siendo herramientas útiles para el análisis de la calidad del aire. En tal sentido, se caracterizó la variación diurna, mensual, estacional y tipos de aerosoles con datos registrados por el fotómetro CIMEL 318T de la red AERONET, operado en la estación del IGP en Huancayo (nivel 2.0, λ = 440 nm), durante el período comprendido entre marzo de 2015 y diciembre de 2017. La evaluación estadística de la relación entre los aerosoles e IRAs se realizó mediante el análisis de correlación de Pearson (r). De acuerdo a los resultados obtenidos, no se encontró una relación estadísticamente significativa entre estas dos variables, por lo que los casos de IRAs estarían más relacionadas a otros factores de riesgo, como climáticos y socioculturales.Item Open Access Caracterización temporal del espesor óptico de aerosoles y su relación con las infecciones respiratorias agudas, Huachac - Chupaca 2015-2017(Universidad Nacional del Centro del Perú, 2020) Gonzales Pérez, María Violeta; Silva Vidal, Yamina; Estevan, RenéLos aerosoles son partículas sólidas o líquidas en suspensión, que residen en la atmósfera durante varias horas, la propiedad óptica de los aerosoles como el Espesor Óptico (EOA) es una medida de la dispersión y absorción de luz visible por las partículas presentes en una columna vertical de la atmósfera, siendo útil para efectos de analizar la calidad del aire, porque es un valor proporcional a la concentración de partículas atmosféricas y que junto con el Exponente de Ångström (α), permite deducir el tipo de aerosoles presentes en la atmósfera. Se caracterizó la variación diurna, mensual, estacional y tipos de aerosoles, con datos registrados por el fotómetro CIMEL 318T de la red AERONET, Estación IGP- Huancayo, nivel 2.0, λ = 440 nm, en el período comprendido entre marzo de 2015 a diciembre de 2017, demostrando que los meses comprendidos en la época poco lluviosa (julio, agosto, septiembre, octubre y noviembre), presentan mayor presencia de aerosoles tipo BIO. Las infecciones respiratorias agudas (IRAs), constituyen un variado grupo de enfermedades provocadas por diversos agentes causales (virus y bacterias) que afectan al sistema respiratorio, existiendo factores de riesgo como la contaminación ambiental. El objetivo de esta investigación fue determinar la relación entre el EOA e IRAs, y de acuerdo a la Correlación de Pearson como prueba de hipótesis hay una probabilidad de error del 20.8 % de no existir relación entre estas dos variables y usando como medida de correlación nos indica que la relación entre estas dos variables es baja, mostrando que los casos de IRAs estarían más relacionadas a otros factores de riesgo como la climática.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 Restricted First two and a half years of aerosol measurements with an AERONET sunphotometer at the Huancayo Observatory, Peru(Elsevier, 2019-07) Estevan, René; Martínez Castro, Daniel; Suárez Salas, Luis; Moya Álvarez, Aldo Saturnino; Silva Vidal, YaminaDirect sun measurements with a CIMEL sunphotometer belonging to the AERONET network have been performed in the Huancayo Observatory, Peru, from March 2015 to August 2017, two and a half years, providing for the first time information about aerosols in the specific area. The prevalence of background conditions in the measurement site has been determined for the period of study. These conditions, which constitute more than 80% of cases, are occasionally altered, mainly by high aerosols loading, as a consequence of biomass-burning events. Biomass-burning periods cover every year from mid-July to mid-October. The identification of these periods has been possible through the classification of aerosols in 6 subtypes. The month with the maximum AOD monthly average is September, and in 2016, the absolute maximum value of 0.91 was registered. The mean AOD value for the study period is 0.10 ± 0.07 and the alpha mean value is 1.49 ± 0.36, indicating presence, of small size aerosols. Some aerosol optical properties were analyzed in order to validate the aerosol classification. The aerosol size distribution revealed a bimodal character with a slight predominance of the fine mode, related to the two main types of aerosols: continental and biomass.Item Open Access Identificación de tipos de aerosoles en el Observatorio de Huancayo, Perú, usando un fotómetro solar AERONET(Instituto Geofísico del Perú, 2020-03) Estevan, René; Martínez Castro, Daniel; Suárez Salas, Luis; Moya Álvarez, Aldo Saturnino; Silva Vidal, YaminaLos aerosoles en la atmósfera juegan un papel importante en la transferencia de radiación solar, ya que, dependiendo del tipo, pueden reflejar o dispersar dicha radiación. Cabe resaltar también que algunos aerosoles son nocivos para la salud humana. En el Observatorio de Huancayo se vienen realizando mediciones de aerosoles con un fotómetro solar perteneciente a la red AERONET (AErosol RObotic NETwork) de la NASA. En este estudio se analizaron los datos desde marzo de 2015 hasta agosto de 2017, con el objetivo de evaluar los tipos de aerosoles y las regiones fuentes de los mismos. Se determinó la prevalencia de condiciones de fondo durante el período analizado. Estas condiciones, que constituyen más del 80 % de los casos, se alteran ocasionalmente debido a altas concentraciones de aerosoles generadas por la quema de biomasa que tienen lugar, no sólo en el Perú, sino también, en países vecinos. Se clasificaron los aerosoles en 6 subtipos permitiendo identificar los periodos de quema de biomasa desde mediados de julio a mediados de octubre, siendo el mes de setiembre donde se registran los máximos valores, tanto en media mensual como en máximo absoluto. Durante el año 2016 se registró el máximo absoluto de toda la serie temporal analizada.Item Restricted Influence of PBL parameterization schemes in WRF_ARW model on short - range precipitation's forecasts in the complex orography of Peruvian Central Andes(Elsevier, 2020-03-01) Moya Álvarez, Aldo Saturnino; Estevan, René; Kumar, Shailendra; Flores Rojas, José Luis; Ticse, Joel J.; Martínez Castro, Daniel; Silva Vidal, YaminaThe study evaluated the sensitivity of the precipitation forecast in the central Andes of Peru of Weather Research and Forecasting (WRF) model to change the planetary boundary layer (PBL) schemes. In that region is located the Mantaro basin, which is one of the most important in the region. Here, the rainfall is very important to the agriculture and to the reserves of drinking water. The simulations were carried out with ten PBL schemes for 19 days in January, February, and March, between 2009 and 2012. Based on the statistical analysis (model vs. observation), the more efficient schemes were determined and analyses of the vertical profiles of some variables are shown. As a result, the schemes that most helped the model in rainfall forecasting were MYNN3 (general and north sector of the basin), Bou-Lac (central sector) and Bretherton-Park (southern sector). The model generally overestimated rainfall in the northern basin, underestimated in the center, and in the south some schemes overestimated and others underestimated. In addition, it was concluded that the boundary layer is more stable in the model than in the observations. The schemes that generated the most rainfall were those that generated a more unstable boundary layer with weaker wind speeds, at least with easterly winds. Another conclusion is that the height of the boundary layer for rainy days in the region at 18 UTC oscillates around 1000 m and that, generally, the wind's velocity changes very little or decreases within the boundary layer and increases above it.Item Open Access Observaciones para la investigación en física atmosférica en los Andes centrales del Perú: Laboratorio de Microfísica Atmosférica y Radiación (LAMAR)(Instituto Geofísico del Perú, 2024-02) Silva Vidal, Yamina; Saavedra Huanca, Miguel; Suárez Salas, Luis; Estevan, René; Flores Rojas, José Luis; Guizado, David; Giráldez, LucyEl Laboratorio de Microfísica Atmosférica y Radiación (LAMAR), implementado en el Observatorio Geofísico de Huancayo del Instituto Geofísico del Perú (IGP) y ubicado en los Andes centrales peruanos, es un recurso esencial para la investigación, monitoreo y generación de capacidades en temas relacionados con la atmósfera y su interacción con la superficie terrestre en los Andes peruanos. LAMAR, establecido con el propósito de generar información que permita comprender los procesos físicos asociados a los eventos meteorológicos extremos, cuenta con una variedad de instrumentos, desde los convencionales hasta los sofisticados, como los radares meteorológicos, los sensores de radiación, precipitación y aerosoles. Los datos generados por LAMAR han contribuido a mejorar el conocimiento sobre los procesos físicos de la atmósfera en los Andes, lo cual ayuda a mejorar los modelos de predicción del tiempo en el Perú, así como el conocimiento sobre los aerosoles atmosféricos y su impacto en la radiación solar. Sin duda, la información recopilada en LAMAR representa un recurso único en el contexto peruano y pronto estará al alcance de la comunidad científica y académica. En este artículo presentamos los instrumentos más relevantes de LAMAR, así como las publicaciones que se generaron en torno a ellos, con el propósito de incentivar futuras investigaciones y colaboraciones científicas.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 Restricted Spatial and Temporal Distribution of Black Carbon in Peru from the Analysis of Biomass Burning Sources and the Use of Numerical Models(Springer, 2023-06) Moya-Álvarez, Aldo S.; Estevan, René; Martínez Castro, Daniel; Silva Vidal, YaminaThe spatial and temporal distribution of biomass burning in Peru and neighboring countries was analyzed during the 2018–2020 period, with emphasis on 2019. To determine the glaciers most affected by BC as a consequence of vegetation burning, simulations were carried out with the WRF-CHEM model, and to diagnose the origin of BC particles received by the Huaytapallana glacier, backward trajectories were built with the HYSPLIT model. It was found that, during the studied period, the burning of biomass emitted large amounts of BC into the atmosphere, while the number of fires in Peru began its most notable increase in the month of July, with maxima between August and September. Comparisons of the number of outbreaks with the Aerosol Optical Depth (AOD) measured at the Huancayo observatory showed a significant correlation. The Ucayali region is the one that contributes the greatest number of outbreaks and the greatest emissions are produced in the south of Loreto. The WRF model showed that the concentrations in July are still low in relation to the August–October period. The mountain ranges that received the greatest impact from BC emissions were Huaytapallana, Huagoruncho, and Vilcabamba. BC transport is mainly oriented from north to south, moving the particles from the areas of greatest burning to the glaciers located in the center and south of the country. BC concentrations over the Cordillera Blanca were lower. The diagnosis of the backward trajectories corroborated the results of WRF-CHEM and showed trajectories mostly from the north.Item Restricted Statistical characterization of vertical meteorological profiles obtained with the WRF-ARW model on the central Andes of Peru and its relationship with the occurrence of precipitation on the region(Elsevier, 2020-07-15) Moya Álvarez, Aldo Saturnino; Martínez Castro, Daniel; Kumar, Shailendra; Flores Rojas, José Luis; Estevan, René; Saavedra Huanca, Miguel; Silva Vidal, YaminaThe work carried out a characterization of tropospheric vertical profiles in rainy and dry seasons by behavior of thermodynamic indices obtained with the WRF model for the period January 2018–March 2019 on the central Andes of Peru and its relationship with rainfall in the region. A case study was also analyzed using sounding observation data. The precipitation observed were taken from 8 meteorological stations located in the Mantaro basin belonging to the National Meteorological Service of Peru. As a results, it was found that the behavior of the thermodynamic parameters responds to the general characteristics of each period. The level of condensation was always higher in the dry period, in which the lower troposphere was also more stable. The KI, TT, Sweat and CAPE indices were always higher in the rainy season, as was water vapor mixing ratio. The vertical shear was mostly higher in the dry period. The parameters that were most informative to precipitation forecasting in rainy period were the precipitation predicted by the model WRF, the average relative humidity of the 600–400 hPa layer and the water vapor mixing ratio in the layer itself. The shear in the 650–500 hPa and 550–400 hPa layer was also informative for two locations. In general, the indices were not very informative for the forecast of extreme rains. For the dry season, the relationship between thermodynamic indices and rainfall was not analyzed because it is very scarce at this time of year. The case study showed that in general, the thermodynamic parameters analyzed for each day, responded to the fact of a rainy day in relation to another dry day.