Roberto Rondanelli

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Verified

Roberto verified their affiliation via an institutional email.

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• PhD
• Professor (Associate) at University of Chile

Cutoff lows are upper level cold-core cyclones that become detached from the mid-latitude westerlies, drifting slowly toward lower latitudes. In southwestern South America, they frequently appear near 30°S and play a significant role in driving rainfall, sometimes bringing intense precipitation to areas that are normally very dry. Because these sys...

Plain Language Summary Before the 2019 tornado outbreak in central Chile, there was very little knowledge about the occurrence of this type of event in the country, despite the large amount of evidence and testimonies. A closer examination of the tornado and waterspout records shows that these phenomena follow a seasonal pattern, with a maximum fre...

During austral winter under neutral ENSO conditions, positive precipitation anomalies in Southwestern South America from 30° ${}^{\circ}$ to 45° ${}^{\circ}$S coincide with strong real‐time multivariate MJO (RMM) Phase 1 events. Using ERA5 composites arranged according to active RMM phases, we found that a three‐part mechanism, traced approximately...

Plain Language Summary Imagine atmospheric rivers (ARs) as massive, flowing rivers in the sky, but instead of water, they carry vapor from the ocean. When these “sky rivers” travel and hit the Andes Mountains in South America, they can cause a lot of rain and snow to fall. This precipitation is often good because it helps fill reservoirs and water...

In late May 2019, at least seven tornadoes were reported within a 24-h period in southern Chile (western South America, 36°–38°S), including EF1 and EF2 events causing substantial damage to infrastructure, dozens of injuries, and one fatality. Despite anecdotal evidence and chronicles of similar historical events, the threat from tornadoes in Chile...

Water scarcity is a pressing global issue driven by increasing water demands and changing climate conditions. Based on novel estimates of water availability and water use in Chile, we examine the challenges and risks associated with groundwater (GW) withdrawals in the country's central-north region (27–35° S), where extreme water stress conditions...

Despite Southern South America being recognized as a hotspot for deep convective storms, little is known about the socio-environmental impacts of high impact weather (HIW) events. Although there have been past efforts to collect severe weather reports in the region, they have been highly fragmented among and within countries, sharing no common prot...

Atmospheric rivers (ARs) are known to produce both beneficial and extreme rainfall, leading to natural hazards in Chile. Motivated to understand moisture transport during AR events, this study performs a moisture budget analysis along 50 zonally elongated ARs reaching the western coast of South America. We identify the convergence of moist air mass...

We provide a dataset of tornadoes and waterspouts in Chile from 1554 to present based in chronicles, newspaper articles, social media, scientific literature and books. The database includes only those events that have been qualified as more than likely a tornado or waterspout based on a subjective qualification by the researchers. For each tornado...

We characterize trends in maximum seasonal daily precipitation (seasonal Rx1day), minimum (Tn), and maximum (Tx) daily temperatures during days with precipitation over continental Chile for the period 1979–2017, using surface stations and the AgERA5 gridded product derived from the ERA5 reanalysis dataset. We also examine seasonal trends of Sea Sur...

Total solar eclipses (TSEs) are impressive astronomical events which have attracted people’s curiosity since ancient times. Their abrupt alterations to the radiation balance have stimulated studies on “Eclipse Meteorology,” most of them documenting events in the Northern Hemisphere while only one TSE (23 November 2003) has been described over Antar...

Water scarcity is a pressing global issue driven by increasing water demands and changing climatic conditions. Based on novel estimates of water availability and water use, we examine the challenges and risks associated with groundwater (GW) withdrawals, focusing on the case of central-north Chile (27−35º S), where extreme water stress conditions p...

The purpose of the present study is to explore the synoptic-scale atmospheric circulation and water vapor transport that contribute to triggering landslides in the mid-Elqui basin (30 • S, 70.5 • W) since the early 20th century. A total of 12 storms during the modern period (1957-2017) were identified from various sources and analyzed using ERA5 Re...

Plain Language Summary Changes in the amount of rain Central Chile gets from year to year is often related to how the atmosphere behaves over the Southern Pacific Ocean. Specifically, it is connected to the interaction between storm tracks and certain wind patterns that respond to changes in the amount of rainfall in tropical areas. Our research sh...

We characterize trends in maximum seasonal daily precipitation (seasonal Rx1day), and minimum (Tn), and maximum (Tx) daily temperatures during days with precipitation over continental Chile for the period 1970-2017, using surface stations and the AgERA5 gridded product derived from the ERA5 reanalysis dataset. We also examine seasonal trends of Sea...

Interannual variability of precipitation in Central Chile has long been associated with changes in the Southern Pacific dry atmospheric dynamics, due to the interaction of the extratropical storm track with the polar anticyclonic circulations established by the Pacific South American (PSA) teleconnection mode, which results from changes in tropical...

Chile es uno de los cuatro focos mundiales que tienden a desarrollar episodios catastróficos de floraciones algales nocivas (FAN) conocidas comúnmente como marea roja. Las FAN han tenido un incremento en las últimas décadas en nuestro país y se han concentrado en la zona sur-austral, en fiordos y canales de las regiones de Los Lagos, Aysén y Magall...

A major storm impacted the subtropical Andes during 28–31 January 2021 producing 4-days accumulated precipitation up to 100 mm over central-south Chile. These are high accumulations even for winter events but the storm occurred in the middle of the summer when precipitation in virtually absent, conferring it an extraordinary character. Similar stor...

This study delves into the photochemical atmospheric changes reported globally during the pandemic by analyzing the change in emissions from mobile sources and the contribution of local meteorology to ozone (O3) and particle formation in Bogotá (Colombia), Santiago (Chile), and Sao Paulo (Brazil). The impact of mobility reductions (50%–80%) produce...

The ozone mixing ratio spatiotemporal variability in the pristine South Pacific Ocean is studied, for the first time, using 21-year-long ozone (O3) records from the entire southern tropical and subtropical Pacific between 1994 and 2014. The analysis considered regional O3 vertical observations from ozonesondes, surface carbon monoxide (CO) observat...

A major storm impacted the subtropical Andes during 28-31 January 2021 producing 4-days accumulated precipitation up to 100 mm over central-south Chile. These are high accumulations even for winter events but the storm occurred in the middle of the summer when precipitation in virtually absent, conferring it an extraordinary character. Similar stor...

We propose a monochromatic low-cost automatic sun photometer (LoCo-ASP) to perform distributed aerosol optical depth (AOD) measurements at the city scale. This kind of network could fill the gap between current automatic ground instruments—with good temporal resolution and accuracy, but few devices per city and satellite products—with global covera...

Durante las últimas décadas, la megasequía (2010-2021), ha impactado fuertemente la disponibilidad de recursos hídricos en gran parte del territorio nacional. Las evidencias observacionales de calentamiento junto al secamiento generalizado han centrado gran parte de los estudios científicos buscando atribuciones tanto en componentes antropogénicas...

The ozone mixing ratio spatio-temporal variability in the pristine southern Pacific Ocean is studied, for the first time, using 21-year long ozone (O3) records from the entire southern tropical and subtropical Pacific, between 1994 and 2014. The analysis considered regional O3 vertical observations from ozonesondes, surface carbon monoxide (CO) obs...

The chemical composition of snow provides insights on atmospheric transport of anthropogenic contaminants at different spatial scales. In this study, we assess how human activities influence the concentration of elements in the Andean mountain snow along a latitudinal transect throughout Chile. The concentration of seven elements (Al, Cu, Fe, Li, M...

This study presents near future (2020–2044) temperature and precipitation changes over the Antarctic Peninsula under the high-emission scenario (RCP8.5). We make use of historical and projected simulations from 19 global climate models (GCMs) participating in Coupled Model Intercomparison Project phase 5 (CMIP5). We compare and contrast GCMs projec...

El comportamiento térmico de la atmósfera en su estructura vertical permite construir forzantes en modelos hidrológicos, estimar la línea de nieves e isoterma cero, así como condiciones de inestabilidad atmosférica relacionadas con la ocurrencia de precipitación convectiva y estudios de contaminación atmosférica. La precipitación, por su lado, es e...

Main physical mechanisms controlling weather and climate in the continental domain of Chile are addressed in this chapter, with particular emphasis on those that are more pertinent to the precipitation regime. In particular, most relevant factors that modulate the rainfall variability, from the intraseasonal time-scale to long-term changes, are dis...

Radars are used to retrieve physical parameters related to clouds and fog. With these measurements, models can be developed for several application fields such as climate, agriculture, aviation, energy, and astronomy. In Chile, coastal fog and low marine stratus intersect the coastal topography, forming a thick fog essential to sustain coastal ecos...

The chemical composition of snow provides insights on atmospheric transport of anthropogenic contaminants at different spatial scales. In this study, we assess how human activities influence the concentration of elements in the Andean mountain snow along a latitudinal transect throughout Chile. The concentration of seven elements (Al, Cu, Fe, Li, M...

In this study, we explored the connection between anomalies in springtime Antarctic ozone and all-year precipitation in the Southern Hemisphere by using observations from 1960–2018 and coupled simulations for 1960–2050. The observations showed that this correlation was enhanced during the last several decades, when a simultaneously increased coupli...

This study investigates the recent near-surface temperature trends over the Antarctic Peninsula. We make use of available surface observations, ECMWF’s ERA5 and its predecessor ERA-Interim, as well as numerical simulations, allowing us to contrast different data sources. We use hindcast simulations performed with Polar-WRF over the Antarctic Penins...

Los resultados presentados en este informe son parte del trabajo interdisciplinario que realiza el Centro de Ciencia del Clima y la Resiliencia (CR)2. El (CR)2 es un centro de excelencia financiado por el programa FONDAP de CONICYT (Proyecto 15110009) en el cual participan cerca de 60 científicos asociados a la Universidad de Chile, la Universidad...

This study evaluates hindcast simulations performed with a regional climate model (RCM, RegCM4) driven by reanalysis data (ERA-Interim) over the Pacific coast and Andes Cordillera of extratropical South America. A nested domain configuration at 0.44∘ ( ∼ 50 km) and 0.09∘ ( ∼ 10 km) spatial resolutions is used for the simulations. RegCM4 is also dri...

Santiago de Chile frequently suffers from atmospheric pollution that contributes to the decrease of solar irradiance on the surface, leading to losses in the energy output of photovoltaic systems. In this study, a simple model is used to estimate the effect of aerosols on the solar irradiance over the city throughout the year, using as input AERONE...

Central Chile, home to more than 10 million inhabitants, has experienced an uninterrupted sequence of dry years since 2010 with mean rainfall deficits of 20–40%. The so‐called Mega Drought (MD) is the longest event on record and with few analogues in the last millennia. It encompasses a broad area, with detrimental effects on water availability, ve...

Central Chile, along the subtropical west coast of South America, has experienced an uninterrupted sequence of dry winters (annual rainfall deficit 20-40%) since 2010. The so called Mega Drought (MD) is the longest event on record and encompasses a broad area, with detrimental effects on water availability, vegetation and forest fires. Local record...

Plain Language Summary Large atmospheric waves can travel from the tropical regions after being excited by deep convective systems over the oceans. Sometimes this tropical rainfall occurs associated to tropical waves that take from 30 to 60 days to travel around the planet, known as the Madden‐Julian Oscillations. The strongest of such Madden‐Julia...

Vertical profiles of black carbon (BC) and other light-absorbing impurities were measured in seasonal snow and permanent snowfields in the Chilean Andes during Austral winters 2015 and 2016, at 22 sites between latitudes 18°S and 41°S. The samples were analyzed for spectrally-resolved visible light absorption. For surface snow, the average mass mix...

En el siglo XXI, el desarrollo de Chile está en juego debido a las amenazas planteadas por el Antropoceno. Esta época se caracteriza por la influencia humana sobre el sistema terrestre. Sin embargo, si se enfrenta con audacia, ofrece una oportunidad para un desarrollo sostenible. Independientemente de si hemos entrado en una nueva era geológica, el...

¿Qué necesita saber una comunidad que ha vivido un desastre socionatural para poder transformarlo en una oportunidad para vivir mejor? El 25 de marzo de 2015 (25M) la fuerza de voluntad de las comunidades de Atacama fue puesta a prueba una vez más cuando severos aluviones, provocados por un evento de intensas lluvias, bajaron por las quebradas afec...

The socio-ecological sensitivity to water deficits makes Chile highly vulnerable to global change. New evidence of a multi-decadal drying trend and the impacts of a persistent drought that since 2010 has affected several regions of the country, reinforce the need for clear diagnoses of the hydro-climate changes in Chile. Based on the analysis of lo...

The role played by tropical teleconnections in the precipitation of Central Chile through Rossby waves propagating over the Pacific basin has been long recognized in studies since the early 1980s. The main source of internannual variability is connected to ENSO through the teleconnections along the Pacific South American sector. The vision we have...

A record-setting temperature of 17.5°C occurred on 24 March 2015 at the Esperanza station located near the northern tip of the Antarctic Peninsula (AP). We studied the event using surface station data, satellite imagery, reanalysis data, and numerical simulations. The MODIS Antarctic Ice Shelf Image Archive provides clear evidence for disintegratio...

We propose a new application of inexpensive LED-based Sun photometers, consisting of measuring the Aerosol Optical Thickness (AOT) with high resolution within metropolitan scales. Previously, these instruments have been used at continental scales by the GLOBE program, but this extension is already covered by more expensive and higher precision inst...

Aqui se busca mejorar la comprensión de los mecanismos dinámicos y termodinámicos que controlan la precipitación en Patagonia, y su posible respuesta ante escenarios futuros de cambio climático.

Geological records reveal a number of ancient, large and rapid negative excursions of the carbon-13 isotope. Such excursions can only be explained by massive injections of depleted carbon to the Earth system over a short duration. These injections may have forced strong global warming events, sometimes accompanied by mass extinctions such as the Tr...

El papel que desempeñan las teleconexiones tropicales en la precipitación de Chile Central ha sido reconocido en estudios desde principios de los 1980s. La visión que se tiene de esta teleconexión involucra, la existencia de un bloqueo, en latitudes altas, y una difluencia que desviaría el flujo de latitudes medias hacia latitudes más bajas durante...

Chile hosts some of the sunniest places on earth, which has led to a growing solar energy industry in recent years. However, the lack of high resolution measurements of solar irradiance becomes a critical obstacle for both financing and design of solar installations. Besides the Atacama Desert, Chile displays a large array of “solar climates” due t...

Se presenta la metodología elaborada para actualizar el balance hídrico en Chile y se muestran los desafíos de la modelación en las cuencas pilotos seleccionadas en el estudio.

Geological records reveal a number of ancient, large and rapid negative excursions of carbon-13 isotope. Such excursions can only be explained by massive injections of depleted carbon to the Earth System over a short duration. These injections may have forced strong global warming events, sometimes accompanied by mass extinctions, for example the T...

To better forecast streamflow and water resource availability, it is important to have an understanding of the meteorological drivers of the orographic precipitation gradient (OPG), especially critical in semiarid mountainous areas. Although forced ascent over topography typically results in precipitation increasing with altitude (positive OPGs), m...

Ozone (O3) soundings have been performed on Easter Island or Rapa Nui (27 8S, 109 8W, 51 m a.s.l.) since 1994 as part of the Global Atmospheric Watch Programme of the World Meteorological Organization. In this work, we analyse 260 soundings compiled over the period 1994�2014, and make the data available for the international community. We character...

Ozone (O3) soundings have been performed on Easter Island or Rapa Nui (27ºS, 109ºW, 51 m a.s.l.) since 1994 as part of the Global Atmospheric Watch (GAW) Programme of the World Meteorological Organization (WMO). In this work, we analyze 260 soundings compiled over the period 1994-2014, and make the data available for the international community. We...

Northern Chile hosts the driest place on Earth in the Atacama Desert. Nonetheless, an extreme precipitation event affected the region on 24-26 March 2015 with 1-day accumulated precipitation exceeding 40 mm in several locations and hourly mean rainfall rates higher than 10 mm h⁻¹, producing floods and resulting in casualties and significant damage....

Future global warming from anthropogenic greenhouse gas emissions will depend on climate feedbacks, the effect of which is expressed by climate sensitivity, the warming for a doubling of atmospheric CO2 content. It is not clear how feedbacks, sensitivity and temperature will evolve in our warming world but past warming events may provide insight. H...

From 18 to 27 March 2015, northern, central, and southern Chile experienced a series of extreme hydrometeorological events. First, the highest surface air temperature ever recorded in Santiago (with reliable records dating to 1877), 36.8°C at Quinta Normal, was measured at 15:47 local time on 20 March 2015. Immediately following this high heat even...

The Atacama Desert has been pointed out as one of the places on earth where the highest surface irradiance may occur. This area is characterized by its high altitude, prevalent cloudless conditions and relatively low columns of ozone and water vapor. Aimed at the characterization of the solar spectrum in the Atacama Desert, we carried out in Februa...

Within large uncertainties in the precipitation response to greenhouse gas forcing, the Southeast Pacific drying stand out as a robust signature within climate models. A precipitation decline, of consistent direction but of larger amplitude than obtained in simulations with historical climate forcing, has been observed in central Chile since the la...

Urban pollution can often impact surrounding, non-urban regions, through advection and dispersal of pollutants by the prevailing winds. Urban regions located upstream of high mountains, such as the Andes, can potentially impact the cryosphere by deposition of particles onto the surface of the snowpack and glaciers. Santiago, the capital of Chile, h...

During the second half of March 2015, a sequence of atmospheric anomalies caused both record temperatures and precipitation in Chile. In only six days, there was both an intense heat wave in the central and southern sections of Chile, and strong precipitation in the northern sections of the country, including in the arid and semiarid regions of the...

Solar radiation reaching Earth’s surface is one of the major drivers of climate dynamics. By setting the surface energy balance, downwelling solar radiation indirectly heats the atmosphere and controls the hydrological cycle. Besides its critical importance as a physical mechanism for driving climate and weather, solar radiation has attracted inter...

We report on an episode of extremely low precipitable water vapour (PWV) of approximately 0.1 mm with a duration of more than 12 h at European Southern Observatory's Paranal observatory [2635 m above sea level (asl)]. Such conditions are more commonly expected at sites at much higher altitude such as ALMA on the Chajnantor plateau (5000 m asl) or o...

Observations were performed in 12 communities of central Chile in order to determine the horizontal gradients of ozone in the Santiago Basin and surrounding valleys. Higher ozone mixing ratios were found northeast of the Santiago Basin and included east of the Aconcagua Valley (~70 km from Santiago) suggesting that photochemical pollution produced...

We explore the relationship between satellite retrievals of aerosol optical depth (AOD) and surface aerosol mass concentrations over a subtropical urban area, namely, Santiago, Chile (33.5°S, 70.6°W, 500 m.a.s.l.). We compare 11 years of AOD from the MODerate resolution Imaging Spectroradiometer (MODIS) with in situ particulate matter mass concentr...

Our group has designed, sourced and constructed a radiosonde/ground-station pair using inexpensive opensource hardware. Based on the Arduino platform, the easy to build radiosonde allows the atmospheric science community to test and deploy instrumentation packages that can be fully customized to their individual sensing requirements. This sensing/t...

The development of scientific instruments was, only a few years ago, confined to universities and electronics companies having highly specialized human and/or technical resources. With the advent of open hardware initiatives, engineers, scientists, hobbyists, and even people with limited electronic skills have been able to tinker with complex elect...

Goldblatt and Zahnle (2011) raise a number of issues related to the possibility that cirrus clouds can pro-vide a solution to the faint young sun paradox. Here, we argue that: (1) climates having a lower than present mean surface temperature cannot be discarded as solutions to the faint young sun paradox, (2) the detrainment from deep con-vective c...

The time that it takes for precipitation to form in warm clouds is an important parameter in cloud physics. An interesting question is whether rainfall occurs faster over warmer regions of the planet or in a warmer climate. As temperature increases, the cloud liquid water content increases in accordance to the saturation along a moist adiabatic tem...

The Elqui valley around 30°S in Chile is located within a semi-arid region in which the mean annual precipitation (80-180 mm) accumulates in austral winter in connection with mid-latitude weather disturbances: fronts and cut-off lows. Given the steep topography of the Andes in this region (0 - 5000 m in ~ 200 km) the flow and precipitation are stro...

Goldblatt and Zahnle (2011) raise a number of issues related to the possibility that cirrus clouds can provide a solution to the faint young sun paradox. Here we argue that some of the criticism is not warranted. In particular, the criticism related to cirrus clouds being an "end member" case of possible clouds depends heavily on models that may ha...

In this thesis, we study observationally the variation of upper level cloud fraction with sea surface temperature in tropical oceanic regions. We also explore the consequences of a cloud feedback, arising from variations in the coverage of thin upper level clouds, in the climate of the Archean using a simple radiative-convective model that includes...

Using TRMM VIRS data, we attempt to replicate the analysis made by Su et al. (2008) to quantify the effect of methodological choices on the magnitude of the observed correlations between upper-level cloud cover and SST. Using brightness temperature thresholds to identify upper-level cloud, we recover a relatively small change in the normalized area...

In this paper we present radiative-convective simulations to test the idea that tropical cirrus clouds, acting as a negative feedback on climate, can provide a solution to the faint young Sun paradox. We find that global mean surface temperatures above freezing can indeed be found for luminosities larger than about 0.8 (corresponding to ~2.9 Ga and...

This paper focuses on the relation between local sea surface temperature (SST) and convective precipitation fraction and stratiform rainfall area from radar observations of precipitation, using data from the Kwajalein atoll ground-based radar as well as the precipitation radar on board the TRMM satellite. We find that the fraction of convective pre...