Steven Lazarus

Steven Lazarus
Florida Institute of Technology · Department of Marine and Environmental Systems

Ph.D Meteorolgy U. Oklahoma

About

83
Publications
8,679
Reads
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1,237
Citations
Additional affiliations
August 2013 - present
Florida Institute of Technology
Position
  • Professor (Full)
July 2013 - June 2014
University of Utah
Position
  • Professor
Description
  • Sabbatical 2013-2014
June 2007 - May 2013
Florida Institute of Technology
Position
  • Professor (Associate)
Education
August 1991 - December 1996
University of Oklahoma
Field of study
  • Meteorology
August 1986 - July 1991
University of Oklahoma
Field of study
  • Meteorology
August 1983 - December 1985
Florida State University
Field of study
  • Meteorology

Publications

Publications (83)
Article
Wave measurements, such as height and period, are important in understanding estuarine and coastal processes as well as air-sea interactions, which are important in the validation of hydrodynamic models and improvements in the parameterizations needed for atmospheric models. This paper presents and evaluates a relatively inexpensive and portable vi...
Poster
Full-text available
A joint University of New Hampshire and Florida Institute of Technology project has successfully launched balloon-borne instruments into thunderstorms over the last three summers. For the summer 2019 campaign, we have made both instrumental and procedural improvements for launching into thunderstorms in central Florida. These enhancements are in ad...
Article
Full-text available
Here we report the first observations of gigantic jets (GJ) by the Geostationary Lightning Mapper (GLM) on board the Geostationary Operational Environmental Satellite − R series (GOES −R). Fourteen GJs produced by Tropical Storm Harvey on 19 August 2017 were observed by both GLM and a ground‐based low‐light‐level camera system. The majority of the...
Article
Full-text available
Gigantic jets are atmospheric electrical discharges that propagate from the top of thunderclouds to the lower ionosphere. They begin as lightning leaders inside the thundercloud, and the thundercloud charge structure primarily determines if the leader is able to escape upward and form a gigantic jet. No observationally verified studies have been re...
Article
High resolution hydrodynamic models are computationally expensive to run – especially if ensemble forecasts are desired. This can be problematic within coastal estuaries which are not well resolved by today's operational meteorological forecast models. As an alternative, this paper evaluates the wind forcing for three setup parameterizations (based...
Article
Full-text available
A computationally efficient method is developed that performs gridded postprocessing of ensemble 10-m wind vector forecasts. An expansive set of idealized WRF Model simulations are generated to provide physically consistent, high-resolution winds over a coastal domain characterized by an intricate land/water mask. The ensemble model output statisti...
Poster
Full-text available
Gamma-ray glows are emissions of gamma rays that last from seconds to minutes and are produced by runaway electrons in high-field regions of thunderclouds. The lightning group at the University of New Hampshire in collaboration with the Florida Institute of Technology has designed balloon-based instrumentation for flying into thunderstorms with the...
Article
This paper presents a method to bias correct and downscale wind speed over water bodies that are unresolved by numerical weather prediction (NWP) models and analyses. The dependency of wind speeds over water bodies to fetch length is investigated as a predictor of model wind speed error. Because model bias is found to be related to the forecast win...
Article
In this study, a four member ensemble of meteorological forcing is generated using the Weather Research and Forecasting (WRF) model in order to simulate a frontal passage event that impacted the Indian River Lagoon (IRL) during March, 2015. The WRF model is run to provide high and low, spatial (0.005° and 0.1°) and temporal (30 min and 6 h) input w...
Article
Full-text available
In this study we analyze the discharge morphologies of five confirmed negative sprite-parent discharges and the associated charge structures of the thunderstorms that produced them. The negative sprite-parent lightning took place in two thunderstorms that were associated with a tropical disturbance in east-central and south Florida. The first thund...
Article
Full-text available
Cold-water conditions have excluded durophagous (skeleton-breaking) predators from the Antarctic seafloor for millions of years. Rapidly warming seas off the western Antarctic Peninsula could now facilitate their return to the continental shelf, with profound consequences for the endemic fauna. Among the likely first arrivals are king crabs (Lithod...
Article
Full-text available
Gamma-ray ‘glows’ are long duration (seconds to tens of minutes) X-ray and gamma-ray emission coming from thunderclouds. Measurements suggest the presence of relativistic runaway electron avalanches (RREA), the same process underlying terrestrial gamma-ray flashes. Here we demonstrate that glows are relatively a common phenomena near the tops of th...
Article
This paper presents a meteorological analysis of a storm that produced two jets, four gigantic jets (GJ), and a starter, which were observed by two radars as well as the Kennedy Space Center 4-Dimensional Lightning Surveillance System on 3 August 2013 in Central Florida. The work is the first application of dual polarization data to a jet-producing...
Article
The Terrestrial Gamma-ray Flash (TGF) is an emission of highly energetic radiation produced by or at least in close association with lightning. Previous investigations attempted to isolate the production mechanisms and production altitude(s) of TGFs as well as macro physical characteristics, while thunderstorm microphysical characteristics were lar...
Article
Full-text available
Probabilistic wind speed forecasts for tropical cyclones from Monte Carlo–type simulations are assessed within a theoretical framework for a simple unbiased Gaussian system that is based on feature size and location error that mimic tropical cyclone wind fields. Aspects of the wind speed probability data distribution, including maximum expected pro...
Data
A computationally efficient method of producing tropical cyclone (TC) wind analyses is developed and tested, using a hindcast methodology, for 12 Gulf of Mexico storms. The analyses are created by blending synthetic data, generated from a simple parametric model constructed using extended best-track data and climatology, with a first-guess field ob...
Article
Full-text available
A computationally efficient method of producing tropical cyclone (TC) wind analyses is developed and tested, using a hindcast methodology, for 12 Gulf of Mexico storms. The analyses are created by blending synthetic data, generated from a simple parametric model constructed using extended best-track data and climatology, with a first-guess field ob...
Article
Full-text available
A wind-wave forecast system, designed with the intention of generating unbiased ensemble wave forecasts for extreme wind events, is assessed. Wave hindcasts for 12 tropical cyclones (TCs) are forced using a wind analysis produced from a combination of the North American Regional Reanalysis (NARR) and a para-metric wind model. The default drag param...
Article
Full-text available
The Unidata Program Center (UPC) worked with the Unidata Users Committee to organize triennial summer workshops on topics of interest to the Unidata community. The 2012 workshop theme, entitled 'navigating Earth system science data', was designed in part to address a two-pronged challenge. The challenge involve how could Unidata best serve the data...
Article
Gamma-ray glows are continuous, long duration gamma- and x-ray emission seen coming from thunderclouds. The Airborne for Energetic Lightning Emissions (ADELE) observed 12 gamma-ray glows during its summer 2009 flight campaign over the areas of Colorado and Florida in the United States. For these glows we shall present their spectra, relationship to...
Article
The Airborne Detector for Energetic Lightning Emissions (ADELE) observed 12 γ-ray glows from thunderstorms near Montana and Florida during its Summer 2009 campaign. These glows have been observed from both the ground and air but this is the first evidence that they are a common, long duration occurrence at the tops of thunderclouds. Glows could be...
Article
Full-text available
On 21 August 2009, the Airborne Detector for Energetic Lightning Emissions (ADELE), an array of six gamma-ray detectors, detected a brief burst of gamma rays while flying aboard a Gulfstream V jet near two active thunderstorm cells. The duration and spectral characteristics of the event are consistent with the terrestrial gamma ray flashes (TGFs) s...
Article
Full-text available
We report on the first search for Terrestrial Gamma-ray Flashes (TGFs) from altitudes where they are thought to be produced. The Airborne Detector for Energetic Lightning Emissions (ADELE), an array of gamma-ray detectors, was flown near the tops of Florida thunderstorms in August/September 2009. The plane passed within 10 km horizontal distance of...
Article
While the Airborne Detector for Energetic Lightning Emissions (ADELE) was designed primarily to study high-energy radiation associated with thunderstorms at aircraft altitude, it can also be used as a mobile ground-based instrument when mounted in a van. ADELE contains scintillation detectors optimized for faint and bright events and a flat-plate a...
Article
Full-text available
The characteristics of thunderstorms that produce terrestrial gamma-ray flashes (TGFs) observed by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) are determined using climatological and meteorological data. RHESSI observed TGFs follow diurnal, seasonal, and geographic patterns that are very similar to those of thunderstorms confi...
Article
Full-text available
Data reduction tools are developed and evaluated using a data analysis framework. Simple (nonadaptive) and intelligent (adaptive) thinning algorithms are applied to both synthetic and real data and the thinned datasets are ingested into an analysis system. The approach is motivated by the desire to better represent high-impact weather features (e.g...
Article
Full-text available
A tropical cyclone (TC) wind speed probability forecast product developed at the Cooperative Institute for Research in the Atmosphere (CIRA) and adopted by the National Hurricane Center (NHC) is evaluated for U.S. land-threatening and landfalling events over four hurricane seasons from 2004 to 2007. A key element of this work is the discernment of...
Article
Terrestrial Gamma-ray Flashes (TGFs) are intense bursts of gamma-rays first observed from space using the BATSE instrument onboard the Compton Gamma Ray Observatory. Recent measurements from the RHESSI spacecraft, along with modeling, show that these flashes most likely originate from altitudes between 15 and 21 km, making it difficult to detect su...
Article
The Airborne Detector for Energetic Lightning Emissions (ADELE) had its first flights in August and September 2009 on the NSF/NCAR Gulfstream GV research aircraft. It flew over and around thunderstorm cells, mostly in Florida, at 13-14 km altitude to search for signatures of relativistic runaway on all timescales. ADELE is designed for extremely hi...
Article
Thunderstorms associated with RHESSI-identified terrestrial gamma-ray flashes (TGFs) tend to be tall tropical thunderstorms in regions of significant lower tropospheric convergence. Yet despite the frequent occurrence of thunderstorms with these attributes within the RHESSI footprint, TGF detection is relatively rare. Tropical Rainfall Measuring Mi...
Article
One of the great mysteries in the atmospheric sciences is the source of terrestrial gamma-ray flashes (TGFs). TGFs are short bursts of gamma-rays observed by satellites in low Earth orbit that come from the atmosphere with energies extending up to several tens of MeV. The Gamma-ray Burst Monitor (GBM) on board the Fermi spacecraft has detected more...
Article
Recent spacecraft observations of terrestrial gamma-ray flashes (TGFs) by Fermi/GBM and aircraft observations of the gamma-ray emissions from thunderclouds by ADELE have shown prominent 511 keV positron annihilation lines, demonstrating large enhancements in the positron populations. These observations show that significant pair-production must be...
Article
Full-text available
In this study we report on issues related to the use of color as a third dimension on graphical representations provided to students. We find that a majority of the students sampled have a preconceived color map regarding temperature, with blue indicating low temperatures and red indicating high temperatures. Attempts to transfer this particular co...
Article
Full-text available
Projected temperature and precipitation trends in Florida appear to be quasi-neutral-with precipitation forecasts more uncertain. These uncertainties are, in part, related to climate models and their inability to resolve aspects of the global circulation and internal oscillations. These problems can be exaggerated at the regional scale due to model...
Article
Recent RHESSI observations suggest that thunderstorms may be the source of terrestrial gamma-ray flashes (TGFs). However, precisely where a TGF occurs within or above the thunderclouds is not know. Furthermore, it is not understood what conditions result in the production of TGFs. In this presentation, we investigate the properties of the thunderst...
Article
Full-text available
High- and low-resolution sea surface temperature (SST) analysis products are used to initialize the Weather Research and Forecasting (WRF) Model for May 2004 for short-term forecasts over Florida and surrounding waters. Initial and boundary conditions for the simulations were provided by a combination of observations, large-scale model output, and...
Conference Paper
Full-text available
This paper presents a study on intelligent data thinning for satellite data. In particular, the focus is on the thinning of the Atmospheric Infrared Sounder (AIRS) profiles. A direct thinning method is first applied to a synthetic data set in order to identify optimal data selection strategies. Experiments on synthetic data suggest that a thinned d...
Article
The Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) has detected over 750 Terrestrial Gamma-ray Flashes (TGFs). The RHESSI data provide a large database for statistical studies of TGF characteristics and production environments, such as location and storm type and evolution. We present a statistical comparison of the spectral characte...
Article
Full-text available
This study investigated student understanding of the use of to represent height and temperature. Fifty-four undergraduates were surveyed. Eight students were chosen interviewed to investigate in more detail the responses provided on the surveys. We found that students have an embedded color scheme for temperatures, with red representing hot and blu...
Article
Full-text available
A sea surface temperature (SST) analysis system designed to initialize short-term atmospheric model forecasts is evaluated for a month-long, relatively clear period in May 2004. System inputs include retrieved SSTs from the Geostationary Operational Environmental Satellite (GOES)-East and the Moderate Reso-lution Imaging Spectroradiometer (MODIS)....
Article
The meteorology associated with two TGF events observed both by the Los Alamos Sferic Array (LASA) in Florida and the RHESSI platform is examined. The events, which occurred on 18 June 2004 and 11 August 2005, were identified to have source altitudes in the upper troposphere - which is substantially lower than what once was originally thought. Prev...
Article
Association of terrestrial gamma-ray flashes (TGFs) with thunderstorm systems has been demonstrated in recent studies. Seasonal frequencies of TGF events observed with the RHESSI spacecraft over the past 4 years show patterns that are highly correlated with regional zones of convergence, such as the intertropical convergence zone (ITCZ). The TGF ge...
Article
As far as we know, nearly all Terrestrial Gamma-Ray Flashes (TGFs) are associated with thunderstorms or at least thunderstorm-rich regions, and many have been shown to be associated with individual lightning flashes via observations of radio atmospherics. More than half of all known TGFs have been observed by the Reuven Ramaty High Energy Solar Spe...
Article
Full-text available
A thorough examination of a parameterization and its potential biases is both very relevant and important. There are numerous, examples in the meteorological literature that address the global application issue. (For example, GCMs often parameterize their subgrid-scale stratiform clouds based on a simple relative humidity relationship whereby the c...
Article
Full-text available
An SST analysis system has been constructed at FIT as part of a COMET funded project to produce near real-time SST analyses for the ARPS/ADAS assimilation and forecast cycle at the Melbourne National Weather Service Forecast Office. The analysis system is fully configured except for some outstanding data quality issues - in particular with respect...
Article
Over the last three years, the RHESSI spacecraft has made a large number of terrestrial gamma-ray flashes (TGFs) observations, resulting in a data set with over five hundred events that cover a wide range of times and geographic positions. Recent studies of the spectral shape of the TGFs and studies on the correlation of TGFs with lightning flashes...
Article
Author Posting. © American Meteorological Society, 2005. This is the author's version of the work. It is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Bulletin of the American Meteorological Society 86 (2005): 1733-1737, doi:10.1175/BAMS-86-12-1733. A g...
Article
Full-text available
The spatial and temporal components of a published wind power parameterization method are evaluated using observed winds (9 m to 90 m) from 7 years of data collected at four towers in the Kennedy Space Center/Cape Canaveral Air Force Station network. The temporal component is governed by two parameterization inputs which represent the amplitude and...
Article
Full-text available
The terrain between grid points is used to modify locally the background error correlation matrix in an objective analysis system. This modification helps to reduce the influence across mountain barriers of corrections to the background field that are derived from surface observations. This change to the background error correlation matrix is teste...