Leila M. V. Carvalho

Leila M. V. Carvalho
University of California, Santa Barbara | UCSB · Department of Geography

PhD

About

135
Publications
33,140
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
5,651
Citations
Additional affiliations
January 2009 - present
January 2009 - June 2016
University of California, Santa Barbara
Position
  • Professor (Full)
Description
  • CLIVAC is dedicated to further understand the Earth's present and future climates on different temporal and spatial scales. With this goal in mind, CLIVAC focuses on observational and modeling analyses in atmospheric and climate sciences
October 1988 - April 2011
Independent Researcher
Position
  • Universidade de São Paulo

Publications

Publications (135)
Article
Full-text available
Fuel break effectiveness in wildland-urban interface (WUI) is not well understood during downslope wind-driven fires even though various fuel treatments are conducted across the western United States. The aim of this paper is to examine the efficacy of WUI fuel breaks under the influence of strong winds and dry fuels, using the 2018 Camp Fire as a...
Article
Full-text available
Previous studies have shown that the Atlantic Multidecadal Oscillation (AMO) and Pacific Decadal Oscillation (PDO) have combined effects on the precipitation (PRP) variability over South America. The combined impacts have been assessed considering four mean states as the averages of the variable anomalies during sub-periods overlapping time interva...
Article
Troposphere to stratosphere exchange is generally driven by deep convection capable of overshooting tropospheric materials contributing to stratospheric chemistry. The La Plata Basin region in South America is known for organized deep convection and mesoscale convective systems. This study employs the Weather Research and Forecasting model to simul...
Article
Full-text available
Previous studies have shown evidence of atmospheric extratropical wave trains modulating sea ice area in the Weddell and Amundsen/Bellingshausen seas on intraseasonal timescales (20-100 d). Here we investigate mechanisms relating intraseasonal extreme sea ice extent and Ekman layer dynamics with emphasis on the Weddell Sea. This study extends from...
Article
Full-text available
Atmospheric rivers (ARs) that reach the complex terrain of High Mountain Asia (HMA) cause significant hydrological impacts for millions of people. While ARs are often associated with precipitation extremes and can cause floods and debris flows affecting populated communities, little is known about ARs that reach as far inland as HMA. This paper cha...
Article
Full-text available
Communities like Santa Barbara, California appear to have it all – beaches, mountains, sunshine, moderate temperatures, small urban population, and close proximity to the large metropolis of Los Angeles. What is not to love? Climate change, drought, flammable vegetation, and naturally prevailing weather conditions make a significant portion of the...
Article
Full-text available
Drought conditions significantly impact human and natural systems in the Tropics. Here, multiple observational and reanalysis products and ensembles of simulations from the Coupled Model Intercomparison Project Phase 5 (CMIP5) are analyzed with respect to drought areal extent over tropical land regions and its past and future relationships to the E...
Chapter
VulnerabilityVulnerability to fire and floodsFlood is ever increasing, placing people and communities at great risk. Climate changeClimate change, drought, overgrown vegetation, and naturally prevailing weather conditions make coastal regions in southern California a prime example of this susceptibility, particularly at or near the urban-wildland i...
Preprint
Full-text available
Atmospheric Rivers (ARs) that reach the complex terrain of High Mountain Asia (HMA) cause significant hydrological impacts for millions of people. While ARs are often associated with precipitation extremes and can cause floods and debris flows affecting populated communities, little is known about ARs that reach as far inland as HMA. This paper cha...
Article
Full-text available
Coastal Santa Barbara (SB) County in Southern California, characterized by a Mediterranean climate and complex topography, is a region prone to downslope windstorms that create critical fire weather conditions and rapidly spread wildfires. The Santa Ynez Mountains, oriented from east to west, rise abruptly from the coast, separating air masses from...
Article
Full-text available
The impact of upstream terrain on the diurnal variability of downslope windstorms on the south‐facing slopes of the Santa Ynez Mountains (SYM) is investigated using numerical simulations. These windstorms, called Sundowners due to their typical onset around sunset, have intensified all major wildfires in the area. This study investigates the role o...
Preprint
Full-text available
Drought conditions significantly impact human and natural systems in the Tropics. Here, multiple observational and reanalysis products and ensembles of simulations from the Coupled Model Intercomparison Project Phase 5 (CMIP5) are analyzed with respect to drought areal extent over tropical land regions and its past and future relationships to the E...
Article
Sundowner winds are a type of downslope windstorms observed on the southern slopes of the Santa Ynez Mountains (SYM) in Santa Barbara, southern California. The name “Sundowner” is due to the onset of strong winds near sunset. Sundowner winds can reach gale force and are extremely dangerous during wildfires. This study presents a climatology of Sund...
Article
Full-text available
Observational studies demonstrate a poleward shift in the South Atlantic Convergence Zone (SACZ) in recent decades with regional impacts on extreme precipitation. However, the relative contribution of anthropogenic forcing and natural variability to the observed trends is presently unknown. To evaluate the main forcings associated with the recent t...
Article
Full-text available
In the past 40 years, the global annual mean surface temperature has experienced a non-uniform warming, differing from the spatially uniform warming simulated by the forced responses of large multi-model ensembles to anthropogenic forcing. Rather, it exhibits significant asymmetry between the Arctic and Antarctic, intermittent and spatially varying...
Article
Full-text available
Climatic changes over the central Himalaya are critical for water resources in downstream regions where hundreds of millions of people live. Warming and drying in this region have both occurred in recent decades, but the associated meteorological factors are difficult to diagnose based on observations from unevenly distributed weather stations, rea...
Article
Full-text available
Ozone in the upper troposphere–lower stratosphere (UTLS) is primarily regulated by tropospheric dynamics. Understanding mechanisms driving ozone variability at the UTLS is crucial to evaluate the transport of mass to and from the lower stratosphere. The El Niño-Southern Oscillation (ENSO) is the primary coupled mode acting on interannual timescales...
Article
Full-text available
Extreme, downslope mountain winds often generate dangerous wildfire conditions. We used the wildfire spread model Fire Area Simulator (FARSITE) to simulate two wildfires influenced by strong wind events in Santa Barbara, CA. High spatial-resolution imagery for fuel maps and hourly wind downscaled to 100 m were used as model inputs, and sensitivity...
Article
Full-text available
On 5 March 2019 12:00 UTC, an atmospheric river (AR) made landfall in Santa Barbara, CA, and lasted approximately 30 h. While ARs are typical winter storms in the area, the extraordinary number of lightning strikes observed near coastal Santa Barbara made this event unique. The Earth Networks Global Lightning Network (ENGLN) detected 8811 lightning...
Article
Full-text available
North, Central, and South America (collectively referred to as the Americas) extend across two hemispheres, and together cover approximately 28% of Earth's land area and are home to about 13% of the world's population. Unique ecosystems, diversified cultures, and communities that inhabit the region rely on precipitation delivered yearly by multiple...
Article
Full-text available
Sundowner winds are downslope gusty winds often observed on the southern slopes of the Santa Ynez Mountains (SYM) in coastal Santa Barbara (SB), California. They typically peak near sunset and exhibit characteristics of downslope windstorms through the evening. They are SB’s most critical fire weather in all seasons and represent a major hazard for...
Article
Full-text available
This study examines the influence of the Atlantic Multidecadal Oscillation (AMO) on the Choco Low-level Jet (CJ) variations during the 1983-2016 period. Considering the September-November (SON) 925 hPa zonal wind index in the CJ core, a significant breakpoint occurs in 1997 with larger values after 1997. The changes in the CJ and Caribbean Low-Leve...
Chapter
Full-text available
The hydrological cycle in High Mountain Asia is of critical importance for water security, agriculture and power generation for one of the most densely populated regions in the world. Glaciers over the central Himalaya have retreated at particularly rapid rates in recent decades, while glacier mass in the Karakoram appears stable. This chapter focu...
Preprint
Full-text available
Abstract. On 5 March 2019 12 UTC, an Atmospheric River (AR) made landfall in Santa Barbara, CA and lasted approximately 30 hours. This AR was one of many that occurred during the winter season in Santa Barbara. However, during this AR, a massive number of lightning pulses were detected by Earth Networks Global Lightning Network (ENGLN) near and off...
Article
Full-text available
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Article
Full-text available
Essential for directing conservation resources is to identify threatened vertebrate regions and diagnose the underlying causalities. Through relating vertebrates and threatened vertebrates to the rainfall-runoff chain, to the food chain, and to the human impact of urbanization, the following relationships are noticed: (i) The Earth’s vertebrates ge...
Article
Full-text available
Purpose of Review Understanding the details of the impact of global warming on the North and South America monsoons is of key importance for the well-being of a great number of inhabitants of the Americas. This review deals with the latest research on this topic. Recent Findings Combined multiple datasets, high-resolution global climate models and...
Article
Full-text available
This study investigates the influence of planetary boundary layer (PBL) schemes and land surface models (LSMs) on the performance of the Weather Research & Forecasting model in simulating the development of downslope windstorms in the lee of the Santa Ynez Mountains in Santa Barbara, California (known as Sundowner winds). Using surface stations, a...
Article
Full-text available
During austral summer (December–January–February or DJF), intense precipitation over central-eastern Brazil is modulated by the South American Monsoon System and the South Atlantic Convergence Zone (SACZ). Previous studies identified spatial variability in precipitation trends over this region, suggestive of a poleward shift of the SACZ in recent y...
Article
Full-text available
The South American low-level jet (SALLJ) east of the Andes plays an important role in regional weather and hydrology by transporting large amounts of moisture from the Amazon to the subtropics. A new methodology is introduced for detecting SALLJ events based on seasonal-percentile thresholds of wind speed and wind shear. Direct comparisons are made...
Article
Full-text available
Glaciers over the central Himalaya have retreated at particularly rapid rates in recent decades, while glacier mass in the Karakoram appears stable. To address the meteorological factors associated with this contrast, 36 years of Climate Forecast System Reanalyses (CFSR) are dynamically downscaled from 1979 to 2015 with the Weather Research and For...
Article
Full-text available
The South America low-level jet (SALLJ) on the eastern slopes of the Andes is a unique climatological feature in the continent. TheSALLJ transports large amounts of moisture and controls the spatiotemporal variability of precipitation in southeast South America.This study shows a remarkable influence of the Atlantic Multidecadal Oscillation (AMO) o...
Article
This study investigates the variability of the seasonal cycle of convection in the Brazilian Amazon basin during the last decades, and examines physical mechanisms that potentially trigger these modifications. A new methodology to evaluate the onset and length of the rainy season using long-term cloud fraction observations from geostationary satell...
Poster
Full-text available
The North and South American Monsoon Systems (NAMS and SAMS, respectively) encompass rainfall patterns produced by similar dynamical mechanisms that involve ocean-land-atmosphere processes at multiple timescales. It has even been proposed that there is a cross-equatorial link between both monsoon systems, that is part of the seasonal transition of...
Article
Full-text available
Atmospheric rivers (ARs) are channels of high water vapor flux that transport moisture from low to higher latitudes on synoptic timescales. In areas of topographical variability, ARs may lead to high-intensity precipitation due to orographic forcing. ARs landfalling along North America’s west coast are linked to extreme events including those leadi...
Article
Full-text available
Understanding the spatio-temporal variability of rainfall over mountainous regions such as the Andes is crucial for the maintenance of water resources and ecosystems. This study provided a comprehensive analysis of the signal, statistical significance and spatial pattern of rainfall trends in central and southern Peruvian Andes (CSPA) from 1965 to...
Article
Full-text available
The Weather Research and Forecasting (WRF) model is used to simulate the spatiotemporal distribution of precipitation over central Asia over the year April 2005 through March 2006. Experiments are performed at 6.7 km horizontal grid spacing, with an emphasis on winter and summer precipitation over the Himalaya. The model and the Tropical Rainfall M...
Article
Full-text available
Resumo Muitos estudos meteorológicos e climatológicos utilizam metodologias que superestimam ou até subestimam a significância estatística dos resultados. Análises que subestimam o papel de tendências e dependência temporal e espacial nos dados podem levar a conclusões errôneas. Por outro lado, análises desnecessariamente rigorosas podem enfraquece...
Article
The National Weather Service (NWS) considers frequent gusty downslope winds, accompanied by rapid warming and decreased relative humidity, among the most significant weather events affecting southern California coastal areas in the vicinity of Santa Barbara (SB). These extreme conditions, commonly known as " sundowners " , have affected the evoluti...
Chapter
The multiscale nature of the South American Monsoon System is presented here in a review of the interannual to decadal variability, intraseasonal variability and regional and mesoscale features of the clouds systems associated with the break and active phases. Although the lack of long records in the Amazon and surrounding areas limits multidecadal...
Article
Numerous studies have projected future changes in High Mountain Asia water resources based on temperature and precipitation from global circulation models (GCMs) under future climate scenarios. Although the potential benefit of such studies is immense, coarse grid-scale GCMs are unable to resolve High Mountain Asia's complex topography and thus hav...
Article
Full-text available
Within the Karakoram and western Himalaya (KH), snowfall from winter westerly disturbances (WD) maintains the region’s snowpack and glaciers, which melt seasonally to sustain water resources for downstream populations. WD activity and subsequent precipitation are influenced by global atmospheric variability and tropical-extratropical interactions....
Chapter
Monsoon systems are unique features of the climate of the Earth and the reality of global warming has important implications for the environment and human society. This chapter provides a brief overview of this important topic.
Article
Full-text available
The Atlantic Intertropical Convergence Zone (A-ITCZ) exhibits variations on several time-scales and plays a crucial role in precipitation regimes of northern South America and western Africa. Here we investigate the variability of the A-ITCZ on intraseasonal time-scales during austral summer (November–March) and winter (May–September) based on a mu...
Article
Based on the daily rainfall data since 1889 in Curitiba, one of the largest cities in southern Brazil, a trend towards increased precipitation and more intense rainfall can be seen. The annual and seasonal volume of rainfall has increased, amounts greater than 10, 20 and 40 mm being observed more often, but with a reduction in the number of rainy d...
Article
Southeast Brazil (SE Brazil) is the most densely populated region in Brazil. Previous studies have shown evidence of positive trends in average precipitation and extreme events in a few locations, suggesting the increase in rainfall-related hazards with potential impacts to urbanized areas of SE Brazil. This study provides a comprehensive analysis...
Article
The impacts of the Madden-Julian oscillation (MJO) on precipitation over Northeast Brazil (NEB, also known as Nordeste) are evaluated based on daily raingauge data from 492 stations over 30-year period (1981–2010). Composites of precipitation, outgoing longwave radiation and moisture- ux anomalies are performed for each phase of the MJO, and over a...
Article
Full-text available
Climate change and its effects on the hydrologic regime of the Amazon basin can impact biogeochemical processes, transportation, flood vulnerability, fisheries and hydropower generation. We examined projections of climate change on discharge and inundation extent in the Amazon basin using the regional hydrological model MGB-IPH with 1-dimensional r...
Article
The Indian monsoon system (IMS) is among the most complex and important climatic features on land. This study proposes a simple and robust method to investigate large-scale variations and changes in the IMS that accounts for fluctuations in amplitude, onset and duration of the summer monsoon, including active and break phases, and the post-monsoon...
Article
Full-text available
The presence of low-lying stratocumulus clouds and fog hasbeen known to modify biophysical and ecological properties in coastal Cal-ifornia where forests are frequently shaded by low-lying clouds or immersed infog during otherwise warm and dry summer months. Summer fog and stratuscan ameliorate summer drought stress and enhance soil water budgets a...
Chapter
Full-text available
The South American Monsoon System (SAMS) is the most important climatic feature of the continent. It provides water resources for millions of people living in rural and urban areas, and is a dominant control on both agriculture and on hydroelectric power generation, which is the primary source of electricity in South America. SAMS exhibits variatio...
Book
This book presents a global overview examining monsoon variability in South Asia, Australian, South America and North American, as well as a focus on glaciers and monsoon systems. Monsoon systems are important components of the Earth's climate and play fundamental roles in water and energy balances. The variability and changes in the monsoons affec...
Poster
Full-text available
This study investigated the impacts of the MJO on station rainfall over the Seridó microregion of Rio Grande do Norte (RN), Northeast Brazil (NEB). The Seridó is one of the driest regions in NEB and has been recognized as particularly vulnerable to desertification by the United Nations Convention to Combat Desertification.
Article
Full-text available
Remotely sensed data are often used as proxies for indirect precipitation measures over data-scarce and complex-terrain areas such as the Peruvian Andes. Although this information might be appropriate for some research requirements , the extent at which local sites could be related to such information is very limited because of the resolution of th...
Book
Full-text available
Tendo em vista as dimensões continentais do Brasil assim como a diversidade de seus regimes cli-máticos e das influências sobre seu clima, é necessário ressaltar a necessidade de estudos observacionais para bem conhecê-lo, em termos de características, mecanismos e variabilidade. O conhecimento do clima presente é o primeiro passo para se conhecer...
Article
Full-text available
The Madden–Julian oscillation (MJO) is the main mode of tropical intraseasonal variations and bridges weather and climate. Because the MJO has a slow eastward propagation and longer time scale relative to synoptic variability, significant interest exists in exploring the predictability of the MJO and its influence on extended-range weather forecast...
Article
Full-text available
Extratropical cyclones, including winter westerly disturbances (WWD) over central Asia, are fundamental features of the atmosphere that maintain energy, momentum, and moisture at global scales while intimately linking large-scale circulation to regional-scale meteorology. Within high mountain Asia, WWD are the primary contributor to regional precip...