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Oceanography and Atmospheric Sciences and Meteorology
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- Cyclones (7)
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- Madden-Julian oscillation (3)
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Articles 1 - 24 of 24
Full-Text Articles in Physical Sciences and Mathematics
Differences Between High Shear / Low Cape Environments In The Northeast Us Favoring Straight-Line Damaging Winds Versus Tornadoes, Michael E. Main, Ross A. Lazear, Lance F. Bosart
Differences Between High Shear / Low Cape Environments In The Northeast Us Favoring Straight-Line Damaging Winds Versus Tornadoes, Michael E. Main, Ross A. Lazear, Lance F. Bosart
Atmospheric & Environmental Sciences
High shear / low CAPE (HSLC) environments are common in the Northeast US and can occur at any time of year. Severe weather in HSLC environments is notoriously hard to predict, often catching both forecasters and the general public off-guard. The goal of this project is to help forecasters to identify HSLC environments favorable for severe weather in the Northeast US, and to discriminate between HSLC environments that are supportive of tornadoes versus those that favor straight-line damaging winds (SDW). A 10-year HSLC severe weather environmental climatology was created for the Northeast US (New England, New York, New Jersey, Pennsylvania). …
Understanding Microphysical Processes Occurring In Lake-Effect Snowbands Using Quasi-Vertical Profiles Of Wsr-88d Parameters, Marquette Rocque
Understanding Microphysical Processes Occurring In Lake-Effect Snowbands Using Quasi-Vertical Profiles Of Wsr-88d Parameters, Marquette Rocque
Atmospheric & Environmental Sciences
Knowing the composition and microphysical processes that occur in lake-effect precipitation systems is important in making sure models capture these processes accurately, and could aid forecasters in predicting snow totals and snow water equivalents. Many studies have shown that processes such as riming and dendritic growth can be seen in dual-polarization radar data through parameters such as equivalent radar reflectivity factor, differential reflectivity (ZDR), correlation coefficient, and differential phase. This research examines WSR-88D data from the KTYX (Montague, NY) radar located on the Tug Hill Plateau for several long-lake-axis-parallel lake-effect systems from the Ontario Winter Lake-effect Systems (OWLeS) field campaign …
Assessing Effective Rhetoric On Twitter In Relation To Forecast Uncertainty In Hurricane Tracks, Erin K. Lynch
Assessing Effective Rhetoric On Twitter In Relation To Forecast Uncertainty In Hurricane Tracks, Erin K. Lynch
Atmospheric & Environmental Sciences
A forecast is only as good as the way it is communicated. As the National Weather Service (NWS) transitions to an Impact-Based Communication style, the new public forecasts discuss how to effectively prepare and protect oneself from harm in the face of severe and significant weather. After severe events, meteorologists need to take the time to analyze the language and style of the rhetoric to assess how effective it was at getting people in harm’s way to take protective actions. It is even more important to understand how information was communicated when there is large uncertainty in the forecast. Uncertainty …
Whole-Canopy Net Ecosystem Exchange And Water Use Efficiency In An Intermittent-Light Environment -- Dynamic Approach, Sergey Nikolayevich Kivalov
Whole-Canopy Net Ecosystem Exchange And Water Use Efficiency In An Intermittent-Light Environment -- Dynamic Approach, Sergey Nikolayevich Kivalov
Legacy Theses & Dissertations (2009 - 2024)
An observed 20-30% increase in forest net ecosystem exchange (NEE) on partly cloudy days is often attributed to there being more uniform canopy illumination by diffuse radiation when clouds are present. However, the sky on such days is typically populated by fair-weather cumulus clouds, bringing dynamically changing shadow-to-light conditions on the order of minutes to the forest, with radiation alternating from 1000 W m^-2 in the clear sky to less than 400 W m^-2 in under-cloud shadows. These dynamically changing conditions cannot be investigated by the conventional time-averaged eddy-covariance flux method, which requires nearly steady-state turbulent conditions over much longer …
Extratropical Cyclones Leading To Extreme Weather Events Over Central And Eastern North America, Alicia Marie Bentley
Extratropical Cyclones Leading To Extreme Weather Events Over Central And Eastern North America, Alicia Marie Bentley
Legacy Theses & Dissertations (2009 - 2024)
Cool-season extreme weather events (EWEs) occurring over central and eastern North America are typically associated with strong extratropical cyclones (ECs) that are governed by varying combinations of baroclinic, diabatic, and barotropic processes. This dissertation investigates the climatology, evolution, and predictability of ECs leading to EWEs over central and eastern North America, and provides a foundation on which to compare ECs leading to EWEs to ordinary ECs forming over and traversing the same regions.
An Analysis Of The Linkages Between Large-Scale Flow Regime Transitions On The Spatiotemporal Distribution Of Clustered Extratropical Cyclone Events Over The Northern Hemisphere, Eric Merton John Bunker
An Analysis Of The Linkages Between Large-Scale Flow Regime Transitions On The Spatiotemporal Distribution Of Clustered Extratropical Cyclone Events Over The Northern Hemisphere, Eric Merton John Bunker
Legacy Theses & Dissertations (2009 - 2024)
An Analysis of the Linkages Between Large-Scale Flow Regime Transitions on the Spatiotemporal Distribution of Clustered Extratropical Cyclone Events over the Northern Hemisphere
Stratospheric And Tropospheric Contributions To The Poleward Energy Flux Across 70°N And 65°S In The Merra-2 And Cesm, Christopher Cardinale
Stratospheric And Tropospheric Contributions To The Poleward Energy Flux Across 70°N And 65°S In The Merra-2 And Cesm, Christopher Cardinale
Legacy Theses & Dissertations (2009 - 2024)
The flux of moist static energy (MSE) across 70°N and 65°S plays a key role in the energy budget and climate of the polar regions. This flux, which provides respectively 98 W m⁻² and 91 W m⁻² heating of the northern and southern polar caps, is usually studied from a vertically integrated perspective. Its vertical structure is examined using the NASA-MERRA-2 reanalysis to compute monthly fluxes of sensible, latent and potential energy across 70°N and 65°S for the period 1980-2016. The flux is bimodal, with peaks in the lower troposphere and in the middle stratosphere, and is near zero at …
The Upper-Level Turbulence, Static Stability And Tropopause Structure Of Tropical Cyclones, Patrick Duran
The Upper-Level Turbulence, Static Stability And Tropopause Structure Of Tropical Cyclones, Patrick Duran
Legacy Theses & Dissertations (2009 - 2024)
Upper-tropospheric thermodynamic processes can play an important role in tropical cyclone (TC) structure and evolution. Despite its importance, until recently few in-situ observations were available in the upper levels of TCs. Two recent field campaigns -- the National Aeronautics and Space Administration (NASA) Hurricane and Severe Storm Sentinel (HS3) and the Office of Naval Research Tropical Cyclone Intensity (TCI) experiment -- provided a wealth of high-altitude observations within TCs. These observations revealed that the upper-level static stability and tropopause structure of TCs can change dramatically with both space and time.
Dry Air, Midlevel Flow, And The Persistence Of Deep Convection In Atlantic Tropical Disturbances, Charles Helms
Dry Air, Midlevel Flow, And The Persistence Of Deep Convection In Atlantic Tropical Disturbances, Charles Helms
Legacy Theses & Dissertations (2009 - 2024)
An analysis of dropsonde-observed relative humidity in the Tropical Storm Gabrielle (2013) pregenesis disturbance suggests the presence of a layer of dry air that is being advected into the disturbance from the north. The focus of this study is on this and similar dry air layers, termed dry air inflow pathways (DAIPs), that are characterized by unidirectional disturbance-relative flow drawing dry air into a tropical disturbance. It is hypothesized that DAIPs act to prevent the establishment of persistent deep convection by importing midlevel
Changes In Extreme Precipitation In The Northeast United States : 1979-2014, Macy Howarth
Changes In Extreme Precipitation In The Northeast United States : 1979-2014, Macy Howarth
Legacy Theses & Dissertations (2009 - 2024)
Extreme precipitation can have significant adverse impacts on infrastructure and property, human health, and local economies. This thesis examines recent changes in extreme precipitation in the Northeast United States, which here includes the states of Maine, New Hampshire, Vermont, New York, Massachusetts, Connecticut, Rhode Island, Pennsylvania, and New Jersey. Daily station data from 58 stations missing less than 5% of days for the years 1979–2014 from the United States Historical Climatology Network was used to analyze both total and extreme precipitation, with the latter defined as the top 1% of days with precipitation.
Predictability Of African Easterly Waves In An Operational Ensemble Prediction System, Travis J. Elless
Predictability Of African Easterly Waves In An Operational Ensemble Prediction System, Travis J. Elless
Legacy Theses & Dissertations (2009 - 2024)
African easterly waves (AEWs) are the primary synoptic-scale weather feature found in sub-Saharan Africa during boreal summer. Many studies have used observations and idealized models to highlight processes associated with the movement and growth of AEWs, yet there have been few studies documenting the performance of operational ensemble prediction systems (EPSs) for these phenomena. Here, the predictability of AEWs in ECMWF EPS forecasts is assessed during two periods of enhanced AEW activity (July--September 2007--2009 and 2011--2013). Specifically, AEW predictability is analyzed through three main areas of focus: 1) verifying AEW position and intensity forecasts, and assessing their relation to convective …
The Relationship Between Tropospheric Synoptic-Scale Events, Vertical Wave Activity Flux, And Sudden Stratospheric Warmings In The Boreal Winter, Hannah Elizabeth Attard
The Relationship Between Tropospheric Synoptic-Scale Events, Vertical Wave Activity Flux, And Sudden Stratospheric Warmings In The Boreal Winter, Hannah Elizabeth Attard
Legacy Theses & Dissertations (2009 - 2024)
Rapid breakdowns of the climatological mid-winter stratospheric polar vortex [i.e., sudden stratospheric warmings (SSWs)] are often preceded by tropospheric blocks. While some studies suggest that blocks can induce the upward wave activity flux (WAF) through the tropopause region that is necessary to trigger an SSW, other studies show no statistical relationship between tropospheric blocks and SSWs. One objective of this dissertation is to elucidate the dynamical relationship between tropospheric blocks and SSWs by exploring the relationship between blocks and tropopause-level upward WAF. Along with analyzing blocks, this dissertation also explores rapidly deepening extratropical cyclones (i.e., bombs) and tropical cyclones that …
Global Response To The Madden-Julian Oscillation As A Function Of Phase Speed In Era-Interim Reanalysis And Miroc5 Model Data, Kaitlyn Krzyzaniak
Global Response To The Madden-Julian Oscillation As A Function Of Phase Speed In Era-Interim Reanalysis And Miroc5 Model Data, Kaitlyn Krzyzaniak
Legacy Theses & Dissertations (2009 - 2024)
Many authors state that the phase speed of the Madden–Julian oscillation (MJO) is near 5ms–1, but observations suggest it varies considerably. MJO propagation typically sets off Rossby wave trains that interact with and alter this extratropical pattern; however, differences in the MJO phase speed could alter the Rossby wave response, leading to a unique response in the extratropics. An understanding of the mechanisms and extratropical responses to variable MJO phase speeds would provide innovative and invaluable insight for subseasonal forecasting.
Projected Changes In Climate, Elevation-Dependent Warming, And Extreme Events Over Continental Ecuador For The Period 2041-2070, Oscar Chimborazo
Projected Changes In Climate, Elevation-Dependent Warming, And Extreme Events Over Continental Ecuador For The Period 2041-2070, Oscar Chimborazo
Legacy Theses & Dissertations (2009 - 2024)
The climate over Ecuador is complex due to several interacting factors, such as its location at the equator, the Andean topography, and several modes of internal variability, including the El Niño–Southern Oscillation (ENSO), affecting the region. In addition, the rapid increase in greenhouse gas concentrations will continue to affect both the mean state and climate variability in Ecuador over the coming decades. Hence, a thorough understanding of both natural and anthropogenic forcings and how they combine to influence Ecuadorian climate is a necessity for decision-making and implementation of adequate adaptation measures. However, the lack of observational data, both in space …
Understanding The Relationship Between Winter Hawaii Precipitation And North Pacific Climate Variability For Past And Present Climate Conditions, Siyu Li
Legacy Theses & Dissertations (2009 - 2024)
Kona lows (KLs) are a type of seasonal cut-off cyclones in the North Pacific around the Hawaiian Islands during the cold season month (Oct.-Apr.). KLs are important for the annual rainfall budget of the Hawaiian Islands. This study investigates what controls the winter precipitation variability over the Hawaiian Islands in the present-day climate and within a long-term paleoclimate simulation. ERA-interim data from 1979-2014 are used for the present-day analysis of the large-scale circulation. The potential vorticity is used as a measure of extratropical synoptic activity. The Hawaii Rainfall Index is from the Rainfall Atlas of Hawaii (seasonal means, 1920-2012). For …
Surface Air Temperature Biases And Other Associated Biases In Gfdl Am4.0 Model, Yilin Lu
Surface Air Temperature Biases And Other Associated Biases In Gfdl Am4.0 Model, Yilin Lu
Legacy Theses & Dissertations (2009 - 2024)
The Atmospheric Model version 4.0 (AM4) is the atmospheric component of the latest climate and Earth system models (CM4 and ESM4) developed by NOAA’s Geophysical Fluid Dynamics Laboratory (GFDL) in Princeton, New Jersey. The AM4 makes some improvements in its radiative flux simulations. As a new model, its performance needs to be evaluated. We analyzed the model’s historical simulations (ten-year simulations from 2001 to 2010), in order to evaluate the diurnal cycle of surface air temperature (Tas) simulated by the AM4 model and perform some diagnostic analyses of the surface energy fluxes to help understand the temperature biases. In comparison …
Field Evaluation Of Portable Air Quality Monitors And Evaluation Of Short-Lived Plume Events Of Atmospheric Pollutants, Joseph Peter Marto
Field Evaluation Of Portable Air Quality Monitors And Evaluation Of Short-Lived Plume Events Of Atmospheric Pollutants, Joseph Peter Marto
Legacy Theses & Dissertations (2009 - 2024)
Availability of low cost optical sensors has allowed for the supplementation of existing air quality infrastructure with portable, adaptive monitors. While these sensors generally cannot offer the same accuracy and precision as established analysis methods, they can still reliably detect changes in pollutant concentration. This study evaluates the performance of two portable air quality enclosures deployed at collocated research sites to determine their accuracy and usefulness in field deployments. One system deployed collocated sensors for measurement of particulate matter mass concentration (Thermo pDR 1500 and TSI DustTrak DRX for PM2.5) and the second system deployed sensors for measurement of black …
Tropical Cyclone Rapid Intensification In Environments Of Upper-Tropospheric Troughs : Environmental Influences And Convective Characteristics, Michael Fischer
Tropical Cyclone Rapid Intensification In Environments Of Upper-Tropospheric Troughs : Environmental Influences And Convective Characteristics, Michael Fischer
Legacy Theses & Dissertations (2009 - 2024)
Intensity forecasts for tropical cyclones that undergo a period of rapid intensification are particularly susceptible to large errors. For those storms that interact with an upper-tropospheric trough, tropical cyclone intensity forecasts are complicated, as upper-tropospheric troughs can provide unique intensification mechanisms, but are often associated with unfavorable environmental conditions. Although tropical cyclones in environments with nearby upper-tropospheric troughs are associated with lesser intensification rates than tropical cyclones in environments devoid of upper-tropospheric troughs, some tropical cyclone--trough interactions are associated with a period of rapid intensification. This dissertation utilizes reanalysis output, satellite observations, and ensemble modeling simulations to understand whether rapid …
On The Role Of Western North Pacific Tropical Cyclones In Shaping The Extratropical Circulation Response To The Madden-Julian Oscillation, Lawrence Christian Gloeckler
On The Role Of Western North Pacific Tropical Cyclones In Shaping The Extratropical Circulation Response To The Madden-Julian Oscillation, Lawrence Christian Gloeckler
Legacy Theses & Dissertations (2009 - 2024)
Relationships between the Madden–Julian oscillation (MJO) and the extratropical circulation have been leveraged extensively to improve subseasonal prediction. However, in certain situations, tropical cyclones (TCs), which often coincide with enhanced MJO activity, can constructively or destructively interfere with MJO organization and common pathways through which the extratropics responds to the MJO. To examine this potential interference, the first portion of this study leverages a statistical experiment to relate West Pacific TC presence in different parts of the basin during a given MJO phase to subsequent remote extratropical circulation outcomes. The results of this experiment demonstrate that significant, high amplitude remote …
What Affects The Phase Speed Of Madden-Julian Oscillation Convection, Robert Setzenfand
What Affects The Phase Speed Of Madden-Julian Oscillation Convection, Robert Setzenfand
Legacy Theses & Dissertations (2009 - 2024)
The Madden-Julian Oscillation (MJO) is the main source of convective and circulation variability on intraseasonal timescales and planetary spatial scales within the tropics. Although the phase speed of the MJO convective envelope is often stated as 5 m s–1, MJO events that occur over the Indo-Pacific warm pool can have a range of phase speeds. This study uses a wavelet to identify MJO convective events with specified phase speeds in a satellite-derived outgoing longwave radiation (OLR) dataset during boreal winter. The wavelet-filtered OLR index is then regressed against basic meteorological variables to extract information about MJO events or signals propagating …
Aerosol Direct Radiative And Cloud Adjustment Effects On Surface Climate Over The Eastern China : Analyses Of Wrf Model Simulations, Yangyang Song
Aerosol Direct Radiative And Cloud Adjustment Effects On Surface Climate Over The Eastern China : Analyses Of Wrf Model Simulations, Yangyang Song
Legacy Theses & Dissertations (2009 - 2024)
Aerosol climate effects consist of the initial forcing of atmospheric radiation perturbation through both the direct radiative effect and the modulation of radiatively-important cloud microphysics, and the subsequent changes in meteorology that also affect cloud macro- and micro-physics. The aerosol-induced cloud adjustment therefore involves many couplings and interactions, and its quantitative evaluation requires the use of model simulations. This study uses WRF model simulated changes in clouds and meteorology due to anthropogenic aerosol increases (versus 1970s) for 2002−2008 summers over the eastern China to address two relevant issues: direct radiative vs. cloud adjustment effects, and their roles in affecting surface …
Influence Of Lightning-Producing Convection On Tropical Cyclone Intensity Change, Stephanie Stevenson
Influence Of Lightning-Producing Convection On Tropical Cyclone Intensity Change, Stephanie Stevenson
Legacy Theses & Dissertations (2009 - 2024)
Lightning observations in tropical cyclones (TCs) over the ocean are a recent advance- ment, and while many studies have noted relationships between lightning and TC intensity change, the relationships are not consistent. This dissertation aims to understand the com- plexities of the relationships between lightning and TC intensity change, and associate the relationships to storm kinematic, thermodynamic, and microphysical processes.
Understanding Large Wind Farm Impacts On Regional Climate And Vegetation Growth From Observational And Modeling Perspectives, Geng Xia
Legacy Theses & Dissertations (2009 - 2024)
In the most recent decade, wind energy has experienced exponential growth worldwide and this rapid increase is expected to continue, particularly over farmlands in the United States. This poses an important question regarding whether the widespread deployment of wind turbines (WTs) will influence surface/near-surface microclimate and vegetation growth. In this dissertation, I investigate the potential wind farm (WF) impacts on regional climate and vegetation growth from both observational and modeling perspectives. High resolution satellite, radiosonde and field observations are used to determine the magnitude and variability of WF-induced changes on surface/near-surface temperatures while the Weather Research and Forecasting (WRF) model …
Climate Change On The Quelccaya Ice Cap, Central Andes, And Its Relationship With The Large-Scale Circulation, Christian Pedro Yarleque Galvez
Climate Change On The Quelccaya Ice Cap, Central Andes, And Its Relationship With The Large-Scale Circulation, Christian Pedro Yarleque Galvez
Legacy Theses & Dissertations (2009 - 2024)
Glaciated areas over the central Andes are highly sensitive to atmospheric forcings, as demonstrated by their current accelerated retreat in response to global warming. The present Thesis is focused on quantifying and assessing future climate change impacts over Quelccaya ice cap (QIC), the world-largest tropical ice body, which is considered as a representative case of the tropical Andean cryosphere. I focused my study on characterizing large-scale forcing and future changes of precipitation and temperature, since they represent the most important variables for accumulation and ablation processes in glaciated mountain regions. In my research I developed tools to overcome the lack …