We acknowledge financial support from the International Foundation for Science, Sweden, Concejo Nacional de Ciencia y Tecnologia CONCYTEC, Peru, and the Wellcome Trust, U.K

El desarrollo de áreas urbanas produce una gran modificación de la superficie de la tierra y los climas locales pueden ser modificados por estos cambios (Changnon, 1978; Lemonsu et al., 2010; Vimal Mishra et al., 2015). En general, los microclimas urbanos son más cálidos que sus alrededores en cualquier momento del día en las ciudades de latitudes medias. Este fenómeno se conoce como isla de calor urbano (UHI) (Oke, 1987; Dimoudia et al., 2013; Seem et al., 2015). La forma y el tamaño de la UHI varía con el tiempo, el clima y los patrones de la superficie urbana (Oke, 1987). Se pueden distinguir dos tipos de UHI: la isla de calor de la capa de dosel urbano (UCL) y la isla de calor de la capa límite urbana (UBL). En general, el UCL se encuentra por debajo del nivel medio del techo y consta de varios microclimas generados por la naturaleza heterogénea de los elementos individuale...

El desarrollo de áreas urbanas produce una gran modificación de la superficie de la tierra y los climas locales pueden ser modificados por estos cambios (Changnon, 1978; Lemonsu et al., 2010; Vimal Mishra et al., 2015). En general, los microclimas urbanos son más cálidos que sus alrededores en cualquier momento del día en las ciudades de latitudes medias. Este fenómeno se conoce como isla de calor urbano (UHI) (Oke, 1987; Dimoudia et al., 2013; Seem et al., 2015). La forma y el tamaño de la UHI varía con el tiempo, el clima y los patrones de la superficie urbana (Oke, 1987). Se pueden distinguir dos tipos de UHI: la isla de calor de la capa de dosel urbano (UCL) y la isla de calor de la capa límite urbana (UBL). En general, el UCL se encuentra por debajo del nivel medio del techo y consta de varios microclimas generados por la naturaleza heterogénea de los elementos individuale...

Hailstorms, while fascinating from a meteorological perspective, pose significant risks to communities, agriculture, and infrastructure. In regions such as the Central Andes of Peru, the characteristics and frequency of these extreme weather events remain largely uncharted. This study fills this gap by investigating the historical frequency and vertical structure of hailstorms in this region. We analyzed historical hailstorm records dating back to 1958 alongside 4 years of observations (2017-2021) from the Parsivel2 disdrometer and a cloud-profiling radar MIRA35c. Our findings indicate a trend of decreasing hail frequency (-0.5 events per decade). However, the p value of 0.07 suggests the need for further investigation, particularly in relation to environmental changes and reporting methods. The results show that hailstorms predominantly occur during the austral summer months, with peak ...

Although climatologically dry, the western slopes of the southern Andes of Peru (WSA) can experience precipitation extremes (PEs) during the summer (December–February) resulting in great economic and human losses. Generally, WSA has a positive upslope gradient in precipitation, meaning more rain falls at higher elevations, but observations have shown this gradient can become negative with higher rainfall near the coastal cities. In this study we analyse 2000–2019 regional atmospheric patterns associated with different upslope precipitation gradients and PEs in WSA using principal component analysis methods and surface station observations. Results show important changes in the atmospheric circulation patterns during the occurrence of PE events. A prevailing pattern of negative southerly wind anomalies and regional warming of the southeastern Pacific Ocean leads to significant increas...

The present study explores the cloud microphysics (MPs) impact on the simulation of two convective rainfall events (CREs) over the complex topography of Andes mountains, using the Weather Research and Forecasting- Advanced Research (WRF-ARW) model. The events occurred on December 29 2015 (CRE1) and January 7 2016 (CRE2). Six microphysical parameterizations (MPPs) (Thompson, WSM6, Morrison, Goddard, Milbrandt and Lin) were tested, which had been previously applied in complex orography areas. The one-way nesting technique was applied to four domains, with horizontal resolutions of 18, 6, and 3 km for the outer ones, in which cumulus and MP parameterizations were applied, while for the innermost domain, with a resolution of 0.75 km, only MP parameterization was used. It was integrated for 36 h with National Centers for Environmental Prediction (NCEP Final Operational Global Analysis (NFL) i...

This work presents results of Aerosol Optical Depth (AOD) and Direct Radiative Force (DRF) at the top of the atmosphere (TOA), obtained during monitoring campaigns carried out at the Huancayo Observatory of the Geophysical Institute of Peru (OH-IGP ) in April and August 2022. In these campaigns, a Sun CIMEL photometer was used to measure the microphysical and optical properties of aerosols at wavelengths ranging from 340 to 1020 nm, and a low-cost Purple-air sensor to quantify the concentration of material particulate (PM), in fine and coarse modes. The AOD results indicated values in the range 0.06-0.22. The daily averages of PM2.5 and PM10 did not exceed Peru’s current Environmental Quality Standards (50 μg/m3 and 100 μg/m3). The air quality index (AQI) calculated for PM2.5 and PM10 was classified as good. On some days during the campaigns, the air quality was classified as moderat...

We describe the results of the study of aerosol optical depth (AOD) and Direct Radiative Forcing (DRF) in Top Of Atmosphere (TOA), obtained from the measurement and monitoring campaign carried out during the XXI Antarctic Peruvian Expedition in the months of January and February 2013 and in the Metropolitan Huancayo Area in the months of June and July 2019. In the Scientific Peruvian Station at Antarctic “Machu Picchu” our used a SP02-L sun photometer, which is within the instrumental framework of the International Polar Year. This instrument has 4 channels: 412 nm, 500 nm, 675 nm and 862 nm, thus allowing direct radiation spectra measurements. And in the MHA we used the BF5 sensor. This instrument measured Direct, Diffuse and Global Radiation in low wavelength. The results calculated of AOD in polar latitudes varied between 0.0646 to 0.1061, in relation to AOD in MHA, presents the v...