The 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 “Bol...

Con el objetivo de implementar una red de monitoreo de partículas (PM10) en Perú, se realiza una investigación con ayuda del modelo de pronóstico e investigaciones sobre el tiempo, acoplado con el modelo de química atmosférica (WRF-CHEM, por sus siglas en inglés) para determinar el transporte y dispersión de dichas partículas, producidas por la quema de biomasa, ya sea en Perú o en regiones aledañas. Se tomaron los datos de emisiones del inventario de incendios del Centro Nacional de Investigaciones Atmosféricas de Estados Unidos (NCAR, por sus siglas en inglés) y como base meteorológica, los datos de salida del modelo meteorológico “Sistema Global de Predicción” (GFS, por sus siglas en inglés). Se seleccionó el periodo junio-agosto de 2015. Se determinó que ocurrió un incremento progresivo del número de focos en la región, que originó un aumento, también prog...

The 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...

A 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.

This study assesses the influence of PM10 on the optical thickness of aerosols in the central Andes of Peru, in addition to analyzing and establishing their circulation patterns from July to October 2017. This particular period is considered herein because the largest biomass burning events are usually recorded during these months. The regional meteorological-chemistry transport model WRF-Chem (version 3.7) was used with the Fire Inventory from NCAR (FINN) fire emissions dataset and aerosol optical depth (AOD) data from the Aerosol Robotic Network monitoring network (AERONET), which has a CIMEL sun photometer located at the Huancayo Observatory, the most important city in the central highlands of Peru. The simulation used a single domain with a grid size of 18 km and 32 vertical levels. Results showed an increase in PM10 concentrations with an increase in the number of fire outbreaks and...

The present study presents a detailed analysis of the diurnal and monthly cycles the surface boundary layer and of surface energy balance in a sparse natural vegetation canopy on Huancayo observatory (12.04° S, 75.32° W, 3313 m ASL), which is located in the central Andes of Peru (Mantaro Valley) during an entire year (May 2018-April 2019). We used a set of meteorological sensors (temperature, relative humidity, wind) installed in a gradient tower 30 m high, a set of radiative sensors to measure all irradiance components, and a set of tensiometers and heat flux plate to measure soil moisture, soil temperatures and soil heat flux. To estimate turbulent energy fluxes (sensible and latent), two flux-gradient methods: the aerodynamic method and the Bowen-ratio energy-balance method were used. The ground heat flux at surface was estimated using a molecular heat transfer equation. The results...

The life cycle of clouds consists of mainly into three phases, namely developing, mature, and dissipating phases. The information about the vertical structure of the precipitation during different phases of development will improve their representation in the cloud models. Whether specific regimes over Peru favor the formation or decay of the cloud systems and how their intensity varies during different phases of development will provide the insight into the precipitation structure over Peru. We used two satellite-based data, namely from Global Precipitation Measurement dual Precipitation Radar (GPM-DPR) and GOES (Geostationary Operational Environmental Satellite) to expose the vertical structure of precipitation during different phases of the precipitating cloud systems (PCSs). A PCS is defined using the GPM based near surface rainfall data and then GOES-based brightness temperature (BT...

The present study comes under the project “MAGNET-IGP: Strengthening the research line in physics and microphysics of the atmosphere (Agreement No 010-2017-FONDECYT)”. Yamina Silva-Vidal, Jose Luis Flores-Rojas and Jairo Valdivia-Prado would like to acknowledge the Peruvian PPR068 programme "Reducción de vulnerabilidad y atención de emergencias por desastres" for financial support of their work. This work was done using computational resources, HPC-Linux -Cluster, from Laboratorio de Dinámica de Fluidos Geofísicos Computacionales at Instituto Geofísico del Perú (Grants 101-2014-FONDECYT, SPIRALES2012, IRD-IGP, Manglares IGP-IDRC, PP068 program).