Raúl Valenzuela ● Profesor Asistente

Water vapor is a key component of the hydrological cycle since it is directly involved in the production of precipitation (rain, snow, hail). The transport of water vapor from the tropics (20ºN-20ºS) is fundamental to produce precipitation in midlatitudes (30ºS-50ºS) were local amounts atmospheric moisture are lower than the water column precipitated during a typical storm. This is especially evident during extreme precipitation events, where precipitation accumulation can surpass 2 or 3 times the local atmospheric water vapor available. Extreme precipitation events (EPEs) are expected to increase due to the anthropogenic climate change, and therefore studies addressing the dynamics and forcing factors of these events are increasingly important. Current research examining the relationship between water vapor transport and precipitation in central-southern Chile have advanced in this direction. However, there is a lack of research aiming to understand water-vapor-precipitation process at the mesoscale, where changes in the order of hours associated to convection are important. Even more, despite many storms in central-southern Chile show convective characteristics (e.g. precipitation rates of 10 mm/h or larger), studies looking at the mesoscale processes has not been addressed so far, partially due to the lack of ground-based weather radars. As a result, this research proposal takes the challenge of studying the transport of water vapor and link it with precipitation processes (stratiform and convective) at the mesoscale level in central and southern Chile by using a suit of observations and numerical modeling. To determine the water vapor mechanisms involved in the precipitation processes, the study will employ an atmospheric moisture budget, which involves the balance between a storage term (precipitation in this case) and the linear interaction between local changes, advection, and convergence of water vapor following an air parcel. The budget will be computed using gridded data from a state-of-the-art atmospheric reanalysis (ERA5), numerical simulations with the Weather Research and Forecasting (WRF) model, and mathematical techniques such as finite differences and the trapezoidal integration rule. In addition, a relatively dense network of GPS deployed in central-southern Chile will provide direct estimates of local changes of the column water vapor, allowing us to perform a thorough validation of both ERA5 and WRF. Precipitation processes will be examined using several sources. The polar orbiting Global Precipitation Measurement (GPM) satellite mission provides global swaths of radar reflectivity using a dual-frequency radar (Ku and Ka bands) in a swath-width of 245 km with 5 km resolution at nadir, and vertical beams spaced at 250 m. Along with radar reflectivity, GPM provides estimates of precipitation rates and a classification of the precipitation type, facilitating the identification of precipitation processes. A vertically pointing precipitation radar (Micro Rain Radar, MRR) is currently installed at Universidad de Concepción and will provide time-height sections of radar reflectivity that will complement GPM observations. In addition, a second MRR is planned to be installed in central Chile to provide further meridional context of precipitation processes. Finally, a couple of optical disdrometers and meteorological stations will deliver surface estimates of precipitation at hourly (and higher) rates. In parallel, ERA5 will provide precipitation estimations and classification (stratiform, convective), while WRF will allow to examine precipitation in detail for selected case studies. At the end of this project, it will be clear what component(s) of the moisture budget are dominating precipitation during EPE storms, clarify the relative importance of stratiform and convective precipitation during EPEs, and elucidate if EPEs with strong convective precipitation are forced by atmospheric instabilities, advection of moisture being lifted by the complex terrain, or moisture convergence occurring over the ocean and moving inland. These results will provide the basis for future efforts looking to improve precipitation forecasting tools.

Chile se ha visto cada vez más afectado por múltiples eventos extremos climáticos que ocurren simultáneamente, como eventos compuestos, o consecutivamente, como eventos en cascada. Los eventos climáticos se consideran compuestos cuando ocurren al mismo tiempo. Por ejemplo, el centro de Chile (la región más poblada del país) se ha visto afectada por sequías frecuentes y severas, agravadas por el aumento de las olas de calor (HWs) que a su vez han favorecido persistentes incendios forestales. Estos eventos extremos han afectado la economía al dañar cultivos y provocar escasez de alimentos para el ganado. Los eventos en cascada actúan como una serie de fichas de dominó que se derrumban. Por ejemplo, en el sur de Chile, las fuertes lluvias orográficas asociadas con potentes ríos atmosféricos (ARs) han provocado graves inundaciones que, al arrastrar sedimentos ricos en nutrientes a lagos y fiordos, a menudo han favorecido floraciones de algas nocivas (HABs). En la misma región, el rápido derretimiento de los campos de hielo patagónicos no solo está canalizando hierro hacia lagos y fiordos (favoreciendo más floraciones de algas), sino que también ha formado cientos de nuevos lagos. El vaciamiento repentino de lagos glaciales (GLOFs) han provocado deslizamientos de tierra e inundaciones que han borrado del mapa pequeños poblados en la Patagonia.

Sistema Articulado de Investigación en Cambio Climático y Sustentabilidad de Zonas Costeras de Chile CUECH/RISUE RED21992

“Volando en El Tiempo” es un cuento para niños y niñas (de 3 a 9 años) que se presenta en un novedoso formato: calendario con cuento de pared. La historia narra el viaje de una lora Tricahue desde la Región de O’Higgins a 12 lugares del país, donde conoce e interactúa con diferentes fenómenos meteorológicos y climatológicos. El producto unirá relatos cortos junto a ilustraciones y tendrá una página para cada mes, la identificación de las cuatro estaciones del año y actividades/preguntas para fomentar la observación de las niñas y niños del tiempo meteorológico. La creación de este producto contempla un equipo multidisciplinario con experiencia en divulgación de la ciencia, ciencias atmosféricas y en divulgación con niños y niñas. Se repartirán 1.500 unidades de los calendarios y además se propone crear un formato digital descargable del calendario y otro del cuento (junto con un audio-cuento) para poder difundir en otros públicos. Esperamos despertar la curiosidad de las niñas y niños que viven en Chile sobre las Ciencias Atmosféricas y Cambio Climático una manera simple: mirando un calendario y pudiendo observar por la ventana o saliendo a ver el cielo y así conocer sobre el tiempo a través del vuelo que hace la lora.

The Chilean Coastal Orographic Precipitation Experiment (CCOPE) was conducted during the austral winter of 2015 (May–August) in the Nahuelbuta Mountains (peak elevation 1.3 km MSL) of southern Chile (38ºS). CCOPE used soundings, two profiling Micro Rain Radars, a Parsivel disdrometer, and a rain gauge network to characterize warm and ice-initiated rain regimes and explore their consequences for orographic precipitation