Browsing by Author "Saavedra Huanca, Miguel"
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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 Restricted Assessing precipitation concentration in the Amazon basin from different satellite‐based data sets(Royal Meteorological Society, 2019-06-15) Zubieta Barragán, Ricardo; Saavedra Huanca, Miguel; Espinoza, Jhan Carlo; Ronchail, Josyane; Sulca Jota, Juan Carlos; Drapeau, Guillaume; Martin‐Vide, JavierDaily precipitation concentration in the Amazon basin (AB) is characterized using concentration index (CI), which is computed from HYBAM Observed Precipitation (HOP) data set, for 1980–2009 period. The ability of four satellite precipitation data sets (TMPA V7, TMPA RT, CMORPH and PERSIANN) to estimate CI is evaluated for 2001–2009 period. Our findings provide new information about the spatial irregularity of daily rainfall distribution over the AB. In addition, the spatial distribution of CI values is not completely explained by rainfall seasonality, which highlights the influence of different weather systems over the AB. The results of rainfall concentration indicate that the distribution of daily rainfall is more regular over northwest (northern Peru) and central Andes. Conversely, Roraima region and a large area of Bolivian Amazon register the highest irregularity in the daily rainfall. Bolivian Amazon also represents regions where the large percentage of total rainfall arises from extreme events (>90th percentile). Heavy rainfall episodes over Roraima region are induced by humidity influx come from Caribbean region, while heavy rainfall events over Bolivian Amazon and Andes region are induced by the northwards propagation of cold and dry air along both sides of Andes Mountains, but only propagate in all tropospheric levels for the Andes. The results also show that PERSIANN and TMPA7 data sets better estimates the daily precipitation concentration for whole AB, but with a relative error 8%. CI estimated from satellites does not agree well with HOP over the Andes and northern Peruvian Amazon. On the other hand, the temporal variability of CI can partly be detected using CMORPH and TMPAV7 data sets over the Peruvian Andes, and central and southern Brazil. Errors in CI estimating might be related to inaccurate estimation of daily rainfall. Finally, we conclude that satellite‐based precipitation data sets are useful for analysing rainfall concentration in some regions of AB.Item Open Access Cambios de la precipitación en el centro del Perú por efectos de la deforestación amazónica(Instituto Geofísico del Perú, 2023-07) Saavedra Huanca, Miguel; Junquas, Clementine; Espinoza, Jhan-Carlo; Silva Vidal, YaminaEste trabajo analiza el impacto de la deforestación amazónica en la precipitación de los Andes centrales del Perú durante la temporada húmeda, haciendo uso del modelo atmosférico Weather Research and Forecasting Model (WRF, por sus siglas en inglés). La región de estudio abarca la ciudad de Lima y localidades ubicadas en la cuenca del río Mantaro, de suma importancia debido a su elevada densidad poblacional. En tal sentido, se configuró el modelo WRF para la región de estudio bajo dos escenarios: uno con la Amazonía sin deforestación y otro con un 40 % de deforestación. Debido a la compleja topografía de la región se utilizaron múltiples dominios de alta resolución en el modelo. Los resultados preliminares muestran que, como consecuencia de la deforestación del 40 % en la Amazonía, se prevén cambios relativos netos en la precipitación en la cuenca del río Mantaro y en las zonas altas de la pendiente oeste de los Andes que podrían alcanzar una reducción de 5 % y un aumento de 5 %, respectivamente. En el futuro, estos cambios podrían tener relevancia para la gestión del agua en la región.Item Open Access Caracterización física de heladas radiativas en el valle del Mantaro(Universidad Nacional Mayor de San Marcos, 2013) Saavedra Huanca, Miguel; Lagos Enríquez, Pablo; Takahashi, Ken; Trasmonte Soto, Grace LiliamEl objetivo de este trabajo de investigación es caracterizar las heladas radiativas que ocurren en el valle del Mantaro mediante el análisis de datos observados y registrados mediante estaciones meteorológicas y de datos de satélite. Para ello se realizaron dos trabajos de campo dentro del observatorio de Huancayo del Instituto Geofísico del Perú. Para la obtención de los datos se instalaron termómetros, geotermómetros y un pirgeómetro; con estos se obtuvieron las temperaturas del aire cercana a la superficie, de la temperatura del suelo hasta los 50 cm de profundidad y cantidad de radiación de onda larga que incide sobre la superficie de la tierra (LW↓). Posteriormente se utilizaron un modelo numérico de transferencia radiativa (SBDART) y un modelo numérico de difusión de calor. El primero de ellos se utilizó para determinar la influencia de la humedad, temperatura y nubosidad de la atmósfera sobre LW↓; el segundo fue elaborado usando las ecuaciones de básicas de balance de energía y de difusión de calor, mediante este modelo se determina la sensibilidad de diferentes factores tales como LW↓, humedad, emisividad, temperatura inicial, etc. Adicionalmente también se validaron algunos modelos empíricos usado para determinar LW↓, para esto se usaron las diferentes funciones en las que por lo general interviene la temperatura de caseta y el vapor de agua ademas de algunas constantes. Finalmente se determina que el factor mas importante que modula la temperatura en la superficie es LW↓, el cual es más influenciada por la humedad del aire en la capa límite y la nubosidad presente. De los modelos empíricos, el modelo de Brunt y Brutsaert son los que mejor estiman la radiación cuando la atmósfera no presenta nubes estratocumulus.Item Open Access Concentración de lluvia diaria y su asociación con eventos hidroclimáticos extremos en la cuenca amazónica(Instituto Geofísico del Perú, 2020-02) Zubieta Barragán, Ricardo; Saavedra Huanca, Miguel; Espinoza, Jhan Carlo; Ronchail, Josyane; Sulca Jota, Juan Carlos; Drapeau, Guillaume; Martin-Vide, JavierEl análisis de datos anuales, estacionales o mensuales de precipitación puede conducir a una interpretación limitada de la distribución espacial y temporal de la lluvia diaria debido a que grandes porcentajes del total anual pueden ocurrir en pocos días. Esta alta concentración de lluvia diaria puede causar erosión de suelos, deslizamientos o inundaciones. La concentración de lluvia diaria para toda la cuenca amazónica (CA) es caracterizada empleando un “Índice de Concentración”, el cual es estimado a partir de un producto grillado de precipitación observada para el periodo 1980-2009. Nuestros hallazgos proveen nueva información acerca de la distribución espacial de la lluvia diaria sobre la CA. Los resultados indican que la concentración de lluvia diaria es relativamente baja en Colombia, Ecuador, norte de Perú y los Andes sobre los 1500 m s. n. m., no obstante, es muy alta en regiones del estado de Roraima en el norte de Brasil y la Amazonía boliviana. Esto explica el por qué algunas regiones de Brasil y Bolivia son más frecuentemente afectadas por eventos de lluvia extrema que conllevan a inundaciones. Asimismo, a pesar de la baja concentración de lluvia estimada en los Andes, ello puede contribuir a incrementar la erosión de suelos o deslizamientos, debido a la interrelación con factores como la heterogeneidad de la lluvia, geología, orografía y vegetación andina.Item Open Access Dataset on the first weather radar campaign over Lima, Perú(Elsevier, 2021-04) Valdivia Prado, Jairo Michael; Scipión, Danny; Milla, Marco; Prado, Josep J.; Espinoza, Juan C.; Cordova, Darwin; Saavedra Huanca, Miguel; Villalobos Puma, Elver Edmundo; Callañaupa Gutierrez, Stephany Magaly; Silva Vidal, YaminaThe first weather radar campaign over Lima, the capital of Peru, a desertic area on the western side of the Peruvian Andes, was carried out to study the occurrence of rain events in summer 2018. The weather radar was installed strategically and was able to overlook three river basins: Rimac, Chillón, and Lurin. An X-band radar (PX-1000) was used, which operates at 9.55 GHz. PX-1000 was built by the Advanced Radar Research Center (ARRC) at the University of Oklahoma (U.S.A.). The radar operated from January 26th to April 1st, 2018, at Cerro Suche located 2910 m ASL and 55 km from the city of Lima. The PX-1000 performed plan-position indicators (PPI) for elevations starting at 0° up to 20°. The data presented here were obtained using a three-dimensional constant-altitude plan position-indicator (3D CAPPI), which was generated by high resolution (250 m) nearest point algorithm.Item Open Access Diurnal cycle of raindrops size distribution in a valley of the Peruvian central andes(MDPI, 2020) Villalobos Puma, Elver Edmundo; Martínez Castro, Daniel; Flores Rojas, José Luis; Saavedra Huanca, Miguel; Silva Vidal, YaminaIn the Central Andes of Peru, convective and stratiform rainfall occurs, frequently associated with convective storms. The raindrop size distributions (RSD), measured by a Parsivel-2 optical disdrometer, were characterized by the variation of their normalized parameters. The RSD dataset includes measurements corresponding to 18 months between 2017 and 2019. As a result, it was found that the mass-weighted mean diameter Dm and the Nw parameter present respectively high and low values, in the interval of 15–20 LST (local standard time), wherein deeper and more active clouds appear. The events including convective rainfall contribute 67.5% of the accumulated total, wherein 92% corresponds to the 15–20 LST interval. It is concluded that the spectral variability of the RSD is strongly controlled by the cloudiness configuration field developing over the west (convection over highlands) and east (convection over Amazon) sides of the valley. In the afternoon, clouds develop and drift to the east, over the Andean valleys and towards the Amazon, intensified by local orographic circulation. The opposite happens at night, when the stratiform rainfall is dominant and it is controlled by clouds, located in the Inter-Andean valley, generated by the convection fields formed over the Amazon forest.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 Impacto del cambio de topografía y cobertura de superficie sobre precipitación y temperatura superficial del aire en la zona central del Perú(Universidad Nacional Mayor de San Marcos, 2019) Saavedra Huanca, Miguel; Moya Álvarez, Aldo SaturninoEstudia la representación de la precipitación y la temperatura superficial del aire mediante el modelamiento numérico con el modelo Weather Research and Forecasting Model (WRF) en la zona central del Perú (entre 10 y 14◦S, alrededor de la cuenca del río Mantaro). El periodo de estudio considera cinco meses de enero, desde el año 2004 hasta el 2008. Para este periodo se cuenta con datos observados de precipitación diaria, temperatura máxima y mínima de 57 estaciones meteorológicas, así como temperatura del aire y precipitación horaria de 7 estaciones automáticas. También tiene en cuenta tres experimentos o simulaciones que usan diferentes fuentes de datos de topografía y uso de suelos (land-use): (1) topografía y land-use de la base de datos de United States Geological Survey (USGS); (2) topografía de la misión Shuttle Radar topography Mission (SRTM) y land-use de USGS, y (3) topografía SRTM y land-use obtenido de Eva et al. (2004). Se encuentra que las dos bases de datos de topografía pueden presentar diferencias por encima de 500 m. Esto se da principalmente en la parte este de la cuenca del Mantaro, y en la región de transición Andes-Amazonía. Sin embargo, como en trabajos previos realizados en otras partes del mundo, el producto SRTM representa mejor las altitudes reales de las estaciones meteorológicas. Así, en la zona de estudio, la tasa de modificación de la temperatura mínima y máxima al cambiar de base de datos topográfico es de -5.7 y -6.6 ◦C.km−1, respectivamente.Item Restricted Impacts of topography and land use changes on the air surface temperature and precipitation over the central Peruvian Andes(Elsevier, 2020-04) Saavedra Huanca, Miguel; Junquas, Clementine; Espinoza, Jhan-Carlo; Silva Vidal, YaminaThis paper focuses on the representation of the air surface temperature and precipitation using high spatiotemporal simulations (3 km–1 h) of the WRF3.7.1 model in the central Peruvian area. It covers, from east to west, the coastal zone, the western slope of the Andes, the Andean Mantaro basin (500–5000 masl), and the Andes-Amazon transition region in the eastern Andes. The study covers the January months from 2004 to 2008. Three experiments were conducted using different topography and land use data sources: (1) a control simulation using the default WRF topography and land use datasets from the United States Geological Survey (USGS); (2) a simulation changing only the topography by using the SRTM topography dataset; and (3) a simulation changing the land use data of (2) by a new dataset adapted from Eva et al. (2004). SRTM topography performed better than the control simulation for representing the actual altitudes of 57 meteorological stations that were used for precipitation and surface air temperature data. As a result, the simulations of experiments (2) and (3) produced lower bias values than that of (1). Topography change (experiment (2)) showed improvements in temperature bias that were directly associated with linear modifications of -5.6 and -6.7 °C∙km⁻¹ in minimum and maximum temperature, respectively. Increasing (decreasing) precipitation with topography or land use change was clearly controlled by changes in the moisture flux patterns and its convergence (divergence) in the Andes-Amazon transition. On the western slope, precipitation increase could be associated with the increase in easterly flow by the smaller altitudes of the Andes mountains in SRTM topography and by increasing evaporation with new land use. Inside the Mantaro Basin, low level moisture flux seems to control the rainfall changes. Overall, relative changes (positive or negative) in precipitation due to topography or land use change could reach values above 25%.Item Open Access Importancia de la representación del uso de suelos en la simulación de la precipitación en los Andes centrales del Perú(Instituto Geofísico del Perú, 2019-11) Saavedra Huanca, Miguel; Silva Vidal, YaminaUna de las herramientas importantes para el estudio del tiempo y clima son los modelos numéricos. Aunque una red de estaciones meteorológicas es determinante en la validación de estos, su ventaja radica en abarcar mayor cobertura espacial, inclusive temporal. Aun así, los modelos son sensibles a otros parámetros tales como la representación de la orografía y el uso de suelos (UdS) de una región específica. Por ejemplo, la orografía puede inducir la generación de precipitación tras facilitar la formación de nubes por enfriamiento de la humedad que asciende por las pendientes. Por otro lado, el UdS también juega un papel importante, ya que además de regular la temperatura del aire según el tipo de cobertura (p.e., asfalto → mayor temperatura; grass → menor temperatura), también puede controlar el flujo de humedad y calor entre la biosfera y la atmósfera (Mahmood y Hubbard, 2003; Zhang et al., 2001). Esto puede ser determinante en la generación de precipitación, ya que las zonas con abundante cobertura vegetal suelen generar climas capaces de reciclar la humedad (Van Der Ent & Savenije, 2011; Keys, 2016)…Item Restricted Physical controls on frost events in the Central Andes of Peru using in situ observations and energy flux models(Elsevier Masson, 2017-05-28) Saavedra Huanca, Miguel; Takahashi, Ken;Radiative frosts are a major hazard to agriculture in the tropical Andes of Peru, but there are very few studies of their physical controls. In this study we focus on identifying and approximately estimating the effect that physical variables have on both the downward surface longwave flux (LW↓) and the minimum temperature (Tmin). Through a combination of case studies and statistical analysis of in situ data in the IGP Huancayo Observatory, we found that low cloud cover (CC), surface specific humidity (q), and soil moisture are key factors controlling the day-to-day variability of Tmin, which is more pronounced in the dry/cool season. We found that all frost days had q < 7 g/kg in the dry season and q < 5 g/kg in the wet season, although it should be emphasized that q covaries with CC and soil moisture. We successfully validated a numerical soil heat diffusion model with data from a field campaign in July 2010 and we used it, together with a radiative transfer model, to estimate the sensitivities of Tmin and LW↓ to atmospheric and soil variables. With these results we estimated the partial contributions of these variables to the overall day-to-day variability in Tmin and LW↓. We found that low cloud cover is the dominant factor, although specific humidity has a comparable role in the wet season. Lack of information on the cloud liquid water path is an important source of uncertainty. Enhanced soil moisture has a strong mitigating effect on frosts, although strong variability of soil moisture in the wet season could contribute substantially to the development of frosts.Item Restricted Potential conditions for fire occurrence in vegetation in the Peruvian Andes(CSIRO Publishing, 2021-10-12) Zubieta Barragán, Ricardo; Prudencio, Fernando; Ccanchi, Yerson; Saavedra Huanca, Miguel; Sulca Jota, Juan Carlos; Reupo, Jorge; Alarco, GloryFire activity in the Peruvian Andes has increased significantly in recent decades, but climatic parameters associated with drought, which may indirectly contribute to the occurrence of severe forest fires, have not yet been investigated. Because fire prevention tools are scarce, strategies for deterring burning are necessary in order to reduce impacts in regions where forest fires usually result from human activity. This study explores the conditions conducive to forest fire in the Andes of Peru. Daily precipitation and temperature observed data from the PISCO gridded dataset for the 2002–2016 period were used. In addition, MODIS satellite images (MOD09A1 product) were collected to characterise Andean vegetation using spectral indices. Analysis of daily temperature and rainfall indicates that climatic parameters such as cumulative precipitation, dry-day frequency and hot-day frequency are statistically associated with conditions that could contribute to increased forest fire occurrence. Our findings suggest that a decrease in the water content of vegetation, estimated by the Global Vegetation Moisture Index during the dry period and wet period onset, can be used to identify potential conditions for forest fire occurrence. This study suggests that forest managers should consider implementing prevention strategies that include continuous monitoring of climate and vegetation parameters.Item Open Access Retraso en el inicio de la temporada de lluvias e incremento de la ocurrencia de incendios(Instituto Geofísico del Perú, 2023-07) Zubieta Barragán, Ricardo; Ccanchi, Yerson; Martínez Grimaldo, Alejandra; Saavedra Huanca, Miguel; Norabuena Ortiz, Edmundo; Alvarez, Sigrid; Ilbay, MercyAl ocurrir un incendio forestal en los Andes, se suele pensar que la causa de este fuego que se propaga surge de la quema agrícola realizada por la propia población. Durante el año 2020, el periodo de la pandemia de la COVID-19, se registró la ocurrencia sin precedentes de incendios forestales en los Andes peruanos. Este estudio evalúa las condiciones climáticas y vegetativas propicias para la ocurrencia de dichos eventos haciendo uso de los datos de precipitación, reflectividad y el registro nacional de incendios (MINAM). El análisis de la precipitación estacional del año 2020 indica que este periodo no está estadísticamente asociado con un periodo de sequía; no obstante, el alto incremento de la frecuencia acumulada de días secos entre agosto y noviembre de 2020, durante el periodo de inicio de lluvias (al igual que los periodos de sequía de 2005, 2010 y 2016), habría desempeñado un rol importante en el aumento de condiciones favorables para la propagación de quemas y, por tanto, de incendios forestales. A ello se añade el contexto de la pandemia de la COVID-19, situación que propició el retorno por parte de la población a la actividad agrícola, lo cual habría favorecido la práctica de quemas con la finalidad de limpiar el terreno previo al cultivo.Item Restricted Seasonal variability of daily evapotranspiration and energy fluxes in the Central Andes of Peru using eddy covariance techniques and empirical methods(Elsevier, 2021-10-15) Callañaupa Gutierrez, Stephany Magaly; Segura Cajachagua, Hans; Saavedra Huanca, Miguel; Flores Rojas, José Luis; Silva Vidal, Yamina; Cuxart, JoanIn this study, we analyze the mechanisms associated to evapotranspiration over the high central Peruvian Andes, a place where evapotranspiration has been poorly characterized. We made use of the eddy covariance system (sonic anemometer and a krypton hygrometer) installed at the Huancayo Observatory (12.04° S, 75.32°, 3330 m.a.s.l.) to document for the first time the hourly, daily and monthly variability of surface energy fluxes from July 2016 to June 2017. The relationship between evapotranspiration and meteorological variables is also examined. Furthermore, we evaluated the performance of three empirical equations that estimate the potential evapotranspiration to explore their adequacy in the central Peruvian Andes. These are the FAO Penman-Monteith (PM), Priestley-Taylor (PT) and Hargreaves. Likewise, the accuracy of the MODIS16A2 evapotranspiration product was also examined...Item Restricted Spatial analysis and temporal trends of daily precipitation concentration in the Mantaro River basin: central Andes of Peru(Springer, 2017-08) Zubieta Barragán, Ricardo; Saavedra Huanca, Miguel; Silva Vidal, Yamina; Giráldez, LucyThe analysis of annual or seasonal data can lead to misinterpretation of spatio-temporal rainfall distribution. A high percentage of total annual precipitation can fall in just a few days, causing floods or landslides. Large economic losses from these events are particularly common in Peru, where the daily precipitation has been poorly investigated. This study presents a spatio-temporal analysis of concentration index over the Mantaro River basin in the central Peruvian Andes. Daily rainfall data recorded at 46 rainfall stations between 1974 and 2004 were selected in this study. In terms of average values, the analysis of daily rainfall indicates that low-intensity events account for 38 % of rainy days but only approximately 9 % of the total rain amount. In contrast, high- and very high-intensity events account for 35 % of rainy days and approximately 71 % of the total rain amount. The results also indicate higher concentration and lower intensity over the Northern and Central regions, compared to Southern region of the basin. Rainfall concentration gives evidence of why some of these places are more likely to be affected by extreme weather events; spatial distribution of event intensity can be partly explained by daily rainfall heterogeneity and orography. Moreover, Mann–Kendall test mostly shows a significant change toward a weaker seasonality of daily precipitation distribution over high-mountain regions.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.Item Restricted The role of drought conditions on the recent increase in wildfire occurrence in the high Andean regions of Peru(CSIRO Publishing, 2023-01-24) Zubieta Barragán, Ricardo; Ccanchi, Yerson; Martínez Grimaldo, Alejandra; Saavedra Huanca, Miguel; Norabuena Ortiz, Edmundo; Alvarez, Sigrid; Ilbay, MercyWildfire occurrence has increased sharply in the last two decades in the Peruvian Andes. There is, however, little research on wildfires and their impacts. This study explores the conditions conducive to wildfire during 2020. MODIS images were collected to estimate the development of vegetation. In addition, ground-based monthly and satellite-based daily precipitation data were collected. Daily precipitation regularity was evaluated using a concentration index (CI), while monthly precipitation was used to estimate the Standard Precipitation Index (SPI). We used also the Global Vegetation Moisture Index (GVMI), which is a useful indicator of vegetation dynamics based on vegetation moisture. Our results do not indicate a direct link between rainfall regularity (lowest CI values) and development of vegetation. Although the SPI drought analysis using seasonal rainfall indicated nearly normal conditions during 2019–2020, analysis of dry-day frequency (DDF) suggests that the dry period played an important role between September and November 2020, producing conditions similar to the droughts of 2005, 2010 and 2016. GVMI also showed below-average values from April to November. We corroborate the usefulness of DDF for monitoring the potential increase in wildfire conditions. A controlled burn policy could offer a more useful way to reduce the impacts of wildfire.Item Restricted Variación estacional de la radiación infrarroja, humedad del suelo y su efecto sobre la temperatura mínima superficial en el Observatorio de Huancayo, Junín(Universidad Nacional Mayor de San Marcos, 2017) Galdos Segura, Andreé William; Ocola Aquise, Leonidas; Silva Vidal, Yamina; Saavedra Huanca, MiguelEl objetivo de este trabajo es evaluar la radiación infrarroja y la humedad del suelo y su efecto sobre la temperatura mínima superficial en el Observatorio de Huancayo, Junín, para ello se ha utilizado datos observados y un modelo de difusión de calor en el suelo, el intervalo de tiempo estudiado va desde agosto del 2014 a agosto del 2016. En la primera parte de los resultados se muestra la caracterización del ciclo diurno y del ciclo estacional de las principales variables que están relacionadas con los cambios de temperatura superficial, como la precipitación, la radiación infrarroja, radiación Solar, humedad específica del aire, temperatura del aire y finalmente la misma temperatura superficial. Así mismo, se calcula el coeficiente de correlación entre estas variables y la temperatura superficial, de ello se resalta que las temperaturas superficiales por debajo de 0◦C están relacionadas con valores de radiación infrarroja menores a 250 W/m2 y humedad especifica del aire menores a 4.3 g/Kg. Con ayuda del modelo se ha encontrado que el enfriamiento de la superficie del suelo se da mayormente por un déficit radiactivo en invierno, mientras que en verano, además de ello, puede darse por flujos de calor latente y/o sensible. Así mismo, los resultados del modelo a diferentes humedades del suelo sugieren que el aumento de la humedad provoca un incremento de la temperatura superficial, aunque las bajas correlaciones (< 0,56) entre los datos observados de ambas variables sugieren que la respuesta de la temperatura superficial con el aumento de la humedad no es necesariamente inmediata. Finalmente, los resultados del balance de energía superficial durante las noches indican que aun cuando la velocidad del viento sea de ∼1m/s, el flujo de calor sensible y/o latente juega un rol importante en el balance de energía, sobre todo en los meses de primavera, verano e inicio de otoño.