Raul Valenzuela

• PhD in Atmospheric Sciences
• Professor (Assistant) at University of O’Higgins

This study documents orographic precipitation forcing along the coastal mountains of northern California during the landfall of a significant winter storm over the period 16-18 February 2004. The primary observing asset is a scanning X-band Doppler radar deployed on the coast at Fort Ross, California, which provides low-level (e.g. below 1 km MSL)...

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...

This study quantifies the impact of atmospheric rivers (AR) on precipitation in southern South America. An AR detection algorithm was developed based on integrated water vapor transport (IVT) from six-hourly CFSR reanalysis data over a 16-year period (2001-2016). AR landfalls were linked to precipitation using a comprehensive observing network that...

South America is experiencing severe impacts from climate change. Although the warming of the subcontinent closely follows the global path, the rise of temperatures has been more pronounced in some regions, which have also seen a parallel increment in the occurrence of droughts and weather conditions associated with enhanced fire risk. Here, we use...

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...

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...

Entre el 21 y 26 de junio del 2023, la Zona Central de Chile experimentó un evento meteorológico extremo caracterizado por la ocurrencia de un intenso río atmosférico zonal (RAZ) con características cálidas. Este último produjo precipitación con isoterma 0ºC cerca de los 3000-m snm, acumulando 750-mm de lluvia en la Cordillera y montos entre 100 y...

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...

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 chapter explores the global and regional footprints of ARs, which are just beginning to be recognized. This chapter begins by highlighting the global climatology of ARs using metrics such as frequency, duration, seasonality, and the fraction of precipitation that can be attributed to ARs. It then highlights regional climatologies of ARs, the u...

Extreme rainfall events are thought to be one of the major threats of climate change given an increase of water vapor available in the atmosphere. However, before projecting future changes in extreme rainfall events, it is mandatory to know current patterns. In this study we explore extreme daily rainfall events along central-southern Chile with em...

This study documents the mean properties and variability of kinematic and precipitation structures associated with orographic precipitation along the coast of Northern California in the context of terrain-trapped airflows (TTAs). TTAs are defined as relatively narrow air masses that consistently flow in close proximity and approximately parallel to...

The Chilean Coastal Orographic Precipitation Experiment (CCOPE) was conducted during the Austral winter of 2015 (May-August) in the Nahuelbuta Mountains (peak elevation 1.3km MSL) of Southern Chile (38° S). CCOPE used soundings, two profiling Micro Rain Radars, a Parsivel disdrometer, and a rain gauge network to characterize warm and ice-initiated...

This study develops an objective method to identify terrain-trapped airflows (TTAs) along the coast of northern California and document their impact on orographic rainfall. TTAs are defined as relatively narrow air masses that consistently flow in close proximity and approximately parallel to an orographic barrier. A 13-winter-seasons dataset is em...

Set of equations described in Weber (1991, JAM) to estimate the standard deviation of wind direction.

Similar to mountainous west coast of North America, the west coast of South America (SA) is strongly affected by heavy orographic precipitation events that result from the landfalling Atmospheric Rivers (AR). When the pre-cold-frontal moisture transport enhances and concentrates over the ocean in the form of a narrow and long corridor heading to th...

Allows to store soundings in HDF5 files. It can download a single date, range of dates, and year.

The Nahuelbuta Mountains are a coastal range of modest height (peak elevation 1.3km ASL) in Southern Chile (38 deg. S). Rain gauge observations reveal a strong orographic enhancement of rainfall over the Nahuelbuta. The interior of the mountains receives about 3.5 m annual rainfall, in contrast to nearby lowland locations that receive about 1 m. Th...

Time-height section using the NOAA 915-Mhz wind profiler. Data collected at Bodega Bay, California during PACJET 2001. Time is from right to left.

Thermodyn is a python module with a collection of thermodynamic functions. The module is hosted on Github: https://github.com/rvalenzuelar/thermodyn Thermodynamic functions included: - saturation vapor pressure (Lowe 1980) - saturation vapor pressure (Bohren and Albrecht 1998) - saturation mixing ratio (Bohren and Albrecht 1998) - dew point (Lawre...

This is not a Dataset but I have it here because ResearchGate does not offer an option for applications development. VITAS is build to create plots that support the analysis of dual-Doppler radar synthesis derived from airborne platforms. The code is being developed and therefore is changing constantly. The current version is a python script worki...

Several past studies have addressed the role of terrain-blocked airflow on orographic precipitation (OP) over relatively large-scale mountain ranges, such as the Cascade Mountains of Oregon, the Sierra Nevada of California, and the European Alps, to name a few. In a broad sense, terrain-blocked flow acts as a virtual barrier, lifting an incoming ai...

Animation made in Matlab and based on Wood and Brown (1986): Single Doppler Velocity Signature Interpretation of Nondivergent Evironmental Winds