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Wrf Forecasts Of Great Plains Nocturnal Low-Level Jet-Driven Mcss. Part Ii: Differences Between Strongly And Weakly Forced Low-Level Jet Environments, Brian J. Squitieri, William A. Gallus Jr. 2018 Iowa State University

Wrf Forecasts Of Great Plains Nocturnal Low-Level Jet-Driven Mcss. Part Ii: Differences Between Strongly And Weakly Forced Low-Level Jet Environments, Brian J. Squitieri, William A. Gallus Jr.

William A. Gallus Jr.

The classic Great Plains southerly low-level jet (LLJ) is a primary factor in sustaining nocturnal convection. This study compares convection-allowing WRF forecasts of LLJ events associated with MCSs in strongly and weakly forced synoptic environments. The depth of the LLJs and magnitude, altitude, and times of the LLJ peak wind were evaluated in observations and WRF forecasts for 31 cases as well as for case subsets of strongly and weakly forced synoptic regimes. LLJs in strongly forced regimes were stronger, deeper, and peaked at higher altitudes and at earlier times compared to weakly forced cases. Mean error MCS-centered composites of ...


The 2015 Plains Elevated Convection At Night Field Project, Bart Geerts, David Parsons, Tammy M. Weckwerth, Michael I. Biggerstaff, Richard D. Clark, Michael C. Coniglio, Belay B. Demoz, Richard A. Ferrare, William A. Gallus Jr., Kevin Haghi, John M. Hanesiak, Petra M. Klein, Kevin R. Knupp, Karen Kosiba, Greg M. McFarquhar, James A. Moore, Amin R. Nehrir, Matthew D. Parker, James O. Pinto, Robert M. Rauber, Russ S. Schumacher, David D. Turner, Qing Wang, Xuguang Wang, Zhien Wang, Joshua Wurman 2018 University of Wyoming

The 2015 Plains Elevated Convection At Night Field Project, Bart Geerts, David Parsons, Tammy M. Weckwerth, Michael I. Biggerstaff, Richard D. Clark, Michael C. Coniglio, Belay B. Demoz, Richard A. Ferrare, William A. Gallus Jr., Kevin Haghi, John M. Hanesiak, Petra M. Klein, Kevin R. Knupp, Karen Kosiba, Greg M. Mcfarquhar, James A. Moore, Amin R. Nehrir, Matthew D. Parker, James O. Pinto, Robert M. Rauber, Russ S. Schumacher, David D. Turner, Qing Wang, Xuguang Wang, Zhien Wang, Joshua Wurman

William A. Gallus Jr.

The central Great Plains region in North America has a nocturnal maximum in warm-season precipitation. Much of this precipitation comes from organized mesoscale convective systems (MCSs). This nocturnal maximum is counterintuitive in the sense that convective activity over the Great Plains is out of phase with the local generation of CAPE by solar heating of the surface. The lower troposphere in this nocturnal environment is typically characterized by a low-level jet (LLJ) just above a stable boundary layer (SBL), and convective available potential energy (CAPE) values that peak above the SBL, resulting in convection that may be elevated, with source ...


Wrf Forecasts Of Great Plains Nocturnal Low-Level Jet-Driven Mcss. Part I: Correlation Between Low-Level Jet Forecast Accuracy And Mcs Precipitation Forecast Skill, Brian J. Squitieri, William A. Gallus Jr. 2018 Iowa State University

Wrf Forecasts Of Great Plains Nocturnal Low-Level Jet-Driven Mcss. Part I: Correlation Between Low-Level Jet Forecast Accuracy And Mcs Precipitation Forecast Skill, Brian J. Squitieri, William A. Gallus Jr.

William A. Gallus Jr.

The Great Plains low-level jet (LLJ) fosters an environment that supports nocturnal mesoscale convective systems (MCSs) across the central United States during the summer months. The current study examines if LLJ forecast accuracy correlates with MCS precipitation forecast skill in 4-km WRF runs. LLJs were classified based on their synoptic background as either strongly forced, cyclonic flow (type C) or weakly forced, anticyclonic flow inertial oscillation driven (type A). Large-scale variables associated with the LLJ were examined. For all LLJs inclusive and the subset of type C LLJs alone, the forecast accuracy of the LLJ total wind direction significantly correlated ...


An Evaluation Of Qpf From The Wrf, Nam, And Gfs Models Using Multiple Verification Methods Over A Small Domain, Haifan Yan, William A. Gallus Jr. 2018 Iowa State University

An Evaluation Of Qpf From The Wrf, Nam, And Gfs Models Using Multiple Verification Methods Over A Small Domain, Haifan Yan, William A. Gallus Jr.

William A. Gallus Jr.

The ARW model was run over a small domain centered on Iowa for 9 months with 4-km grid spacing to better understand the limits of predictability of short-term (12 h) quantitative precipitation forecasts (QPFs) that might be used in hydrology models. Radar data assimilation was performed to reduce spinup problems. Three grid-to-grid verification methods, as well as two spatial techniques, neighborhood and object based, were used to compare the QPFs from the high-resolution runs with coarser operational GFS and NAM QPFs to verify QPFs for various precipitation accumulation intervals and on two grid configurations with different resolutions. In general, NAM ...


Adapting The Sal Method To Evaluate Reflectivity Forecasts Of Summer Precipitation In The Central United States, John R. Lawson, William A. Gallus Jr. 2018 Iowa State University

Adapting The Sal Method To Evaluate Reflectivity Forecasts Of Summer Precipitation In The Central United States, John R. Lawson, William A. Gallus Jr.

William A. Gallus Jr.

The Structure Amplitude Location (SAL)methodwas originally developed to evaluate forecast accumulated-precipitation fields through identification and comparison of objects in both the forecast and the observed fields. This study describes a small modification for use with instantaneous composite-reflectivity forecasts, where objects’ minimum size and reflectivity thresholds are prescribed. Both the original and modified SAL methods are used to evaluate daily 0000UTC 12-km North American Model (NAM) forecasts, against NCEP/EMC 4-km Stage IV accumulated-precipitation estimates, during the summer of 2015 for a central US domain. Results show substantial sensitivity to the reflectivity threshold. This is likely related to sampling more ...


An Initial Assessment Of Radar Data Assimilation On Warm Season Rainfall Forecasts For Use In Hydrologic Models, Ben A. Moser, William A. Gallus Jr., Ricardo Mantilla 2018 Iowa State University

An Initial Assessment Of Radar Data Assimilation On Warm Season Rainfall Forecasts For Use In Hydrologic Models, Ben A. Moser, William A. Gallus Jr., Ricardo Mantilla

William A. Gallus Jr.

The effect of introducing radar data assimilation into the WRF Model to improve high-resolution rainfall forecasts that are used for flash flood forecasting is analyzed. The authors selected 12 heavy rainfall events and performed two WRF 24-h simulations that produced quantitative precipitation forecasts (QPFs) for each, one using the standard configuration in forecast mode (QPF-Cold) and one using radar data assimilated at initialization (QPF-Hot). Simulation outputs are compared with NWS stage IV QPEs for storm placement, area over threshold coverage, and equitable threat scores. The two QPF products and stage IV data are used to force the distributed hydrological model ...


On Contrasting Ensemble Simulations Of Two Great Plains Bow Echoes, John Lawson, William A. Gallus Jr. 2018 Iowa State University

On Contrasting Ensemble Simulations Of Two Great Plains Bow Echoes, John Lawson, William A. Gallus Jr.

William A. Gallus Jr.

Bow echo structures, a subset of mesoscale convective systems (MCSs), are often poorly forecast within deterministic numerical weather prediction model simulations. Among other things, this may be due to the inherent low predictability associated with bow echoes, deficient initial conditions (ICs), and inadequate parameterization schemes. Four different ensemble configurations assessed the sensitivity of the MCSs’ simulated reflectivity and radius of curvature to the following: perturbations in initial and lateral boundary conditions using a global dataset, different microphysical schemes, a stochastic kinetic energy backscatter (SKEB) scheme, and a mix of the previous two. One case is poorly simulated no matter which ...


Ensemble Cloud-Resolving Modelling Of A Historic Back-Building Mesoscale Convective System Over Liguria: The San Fruttuoso Case Of 1915, Antonio Parodi, Luca Ferraris, William A. Gallus Jr., Maurizio Maugeri, Luca Molini, Franco Siccardi, Giorgio Boni 2018 CIMA Research Foundation

Ensemble Cloud-Resolving Modelling Of A Historic Back-Building Mesoscale Convective System Over Liguria: The San Fruttuoso Case Of 1915, Antonio Parodi, Luca Ferraris, William A. Gallus Jr., Maurizio Maugeri, Luca Molini, Franco Siccardi, Giorgio Boni

William A. Gallus Jr.

Highly localized and persistent back-building mesoscale convective systems represent one of the most dangerous flash-flood-producing storms in the north-western Mediterranean area. Substantial warming of the Mediterranean Sea in recent decades raises concerns over possible increases in frequency or intensity of these types of events as increased atmospheric temperatures generally support increases in water vapour content. However, analyses of the historical record do not provide a univocal answer, but these are likely affected by a lack of detailed observations for older events. In the present study, 20th Century Reanalysis Project initial and boundary condition data in ensemble mode are used to ...


Wrf Summer Extreme Daily Precipitation Over The Cordex Arctic, Justin M. Glisan, William J. Gutowski Jr. 2017 glisanj@iastate.edu

Wrf Summer Extreme Daily Precipitation Over The Cordex Arctic, Justin M. Glisan, William J. Gutowski Jr.

William J. Gutowski, Jr.

We analyze daily precipitation extremes produced by a six-member ensemble of the Pan-Arctic Weather Research and Forecasting (WRF) that simulated 19 years on the Coordinated Regional Climate Downscaling Experiment (CORDEX) Arctic domain for the Arctic summer. Attention focuses on four North American analysis regions defined using climatological records, regional weather patterns, and geographical/topographical features. We compare simulated extremes with those occurring at corresponding observing stations in the U.S. National Climate Data Center's Global Summary of the Day. Our analysis focuses on variations in features of the extremes such as magnitudes, spatial scales, and temporal regimes between regions ...


Temperature-Dependent Daily Variability Of Precipitable Water In Special Sensor Microwave/Imager Observations, William J. Gutowski Jr., Elizabeth A. Lindemulder, Kari Jovaag 2017 Iowa State University

Temperature-Dependent Daily Variability Of Precipitable Water In Special Sensor Microwave/Imager Observations, William J. Gutowski Jr., Elizabeth A. Lindemulder, Kari Jovaag

William J. Gutowski, Jr.

We use retrievals of atmospheric precipitable water from satellite microwave observations and analyses of near-surface temperature to examine the relationship between these two fields on daily and longer timescales. The retrieval technique producing the data used here is most effective over the open ocean, so the analysis focuses on the southern hemisphere's extratropics, which have an extensive ocean surface. For both the total and the eddy precipitable water fields, there is a close correspondence between local variations in the precipitable water and near-surface temperature. The correspondence appears particularly strong for synoptic and planetary scale transient eddies. More specifically, the ...


Effects Of Spectral Nudging In Wrf On Arctic Temperature And Precipitation Simulations, Justin M. Glisan, William J. Gutowski Jr., John J. Cassino, Matthew E. Higgins 2017 Iowa State University

Effects Of Spectral Nudging In Wrf On Arctic Temperature And Precipitation Simulations, Justin M. Glisan, William J. Gutowski Jr., John J. Cassino, Matthew E. Higgins

William J. Gutowski, Jr.

Spectral (interior) nudging is a way of constraining a model to be more consistent with observed behavior. However, such control over model behavior raises concerns over how much nudging may affect unforced variability and extremes. Strong nudging may reduce or filter out extreme events since nudging pushes the model toward a relatively smooth, large-scale state. The question then becomes: what is the minimum spectral nudging needed to correct biases while not limiting the simulation of extreme events? To determine this, case studies were performed using a six-member ensemble of the Pan-Arctic Weather Research and Forecasting model (WRF) with varying spectral ...


Meeting Summary: Project To Intercompare Regional Climate Simulations, William J. Gutowski Jr., Eugene S. Takle, Raymond W. Arritt 2017 Iowa State University

Meeting Summary: Project To Intercompare Regional Climate Simulations, William J. Gutowski Jr., Eugene S. Takle, Raymond W. Arritt

William J. Gutowski, Jr.

The Project to Intercompare Regional Climate Simulations (PIRCS) modelers workshop proceedings are discussed. An underlying theme of the discussions was the goal of the PIRCS.


Gcm Simulations Of The Three-Dimensional Propagation Of Stationary Waves, Song Yang, William J. Gutowski Jr. 2017 Atmospheric and Environmental Research, Inc.

Gcm Simulations Of The Three-Dimensional Propagation Of Stationary Waves, Song Yang, William J. Gutowski Jr.

William J. Gutowski, Jr.

Plumb's formulation of the stationary wave activity flux is used to determine how well versions of the GFDL and NCAR general circulation models simulate the sources, sinks, and horizontal propagation of atmospheric stationary waves, which play an important role in determining regional climate. The wave activity flux provides insight into the simulation of nondynamic as well as dynamic processes in these models. Model performances for current climate simulations are evaluated with respect to NMC analyses averaged over 1978–1990. The models fare best when the stationary wave forcing is strongest, that is, in the wintertime Northern Hemisphere, where they ...


Exploring Energy, Comfort, And Building Health Impacts Of Deep Setback And Normal Occupancy Smart Thermostat Implementation, Zachary Ethan Alderman 2017 University of Arkansas, Fayetteville

Exploring Energy, Comfort, And Building Health Impacts Of Deep Setback And Normal Occupancy Smart Thermostat Implementation, Zachary Ethan Alderman

Theses and Dissertations

As smart thermostat adoption rates continue to increase, it becomes worthwhile to explore what unanticipated outcomes may result in their use. Specific attention was paid to smart thermostat impacts to deep setback and normal occupancy states in a variety of conditions while complying with the ventilation and temperature requirements of ASHRAE 90.2-2013. Custom weather models and occupancy schedules were generated to efficiently explore a combination of weather conditions, building constructions, and occupancy states. The custom modeling approach was combined with previous experimental data within the Openstudio graphics interface to the EnergyPlus building modeling engine. Results indicate smart thermostats add ...


An Observational And Modeling Study Of Mesoscale Airmasses With High Theta-E, Lawrence Wolfgang Hanft 2017 University of Nebraska-Lincoln

An Observational And Modeling Study Of Mesoscale Airmasses With High Theta-E, Lawrence Wolfgang Hanft

Dissertations & Theses in Earth and Atmospheric Sciences

Typically, the cool side of an airmass boundary is stable to vertical motions due to its associated negative buoyancy. However, under certain conditions, the air on the cool side of the boundary can undergo a transition wherein it assumes an equivalent potential temperature and surface-based convective available potential energy that is higher than that of the airmass on the warm side of the boundary. The resultant airmass is herein referred to as a mesoscale airmass with high theta-e (MAHTE).

Results are presented from an observational and mesoscale modeling study designed to examine MAHTE characteristics and the processes responsible for MATHE ...


Use Of Long Term Weather Data And Spatially Delineated Field Attributes To Predict Water And Energy Conservation From Variable Rate Irrigation, Sahil Sharma 2017 University of Nebraska - Lincoln

Use Of Long Term Weather Data And Spatially Delineated Field Attributes To Predict Water And Energy Conservation From Variable Rate Irrigation, Sahil Sharma

Biological Systems Engineering--Dissertations, Theses, and Student Research

The declining levels of the Ogallala aquifer calls for more judicious use of water. Studies have shown that VRI has the potential for water savings. But adoption of VRI is still very low. The major reason is lack of information on the returns from the VRI systems and its feasibility in different fields. Also, a quantification of the required reduction in prices of VRI is necessary. So, an economic return analysis of VRI strategies was done to compare it to uniform irrigation management (UIM) using a water balance model based on long term weather data and field properties for a ...


Embroidered Meteorology, Bettina L. Matzkuhn 2017 artist, independent

Embroidered Meteorology, Bettina L. Matzkuhn

Artizein: Arts and Teaching Journal

Weathering is a series of embroidered works that explore the symbolic and cartographic language of meteorology. Through research, mentorship and the physical work, my understanding and anxiety around weather has grown. Making art is a learning process for me: the haptic is a means for understanding. From embroidered world maps to animation to painted laundry, I conflate the intricacy of textiles with the complicated nature of the atmosphere.


Informing Responders Using Gis And Gps, Deidre McCarthy 2017 Cultural Resources GIS Facility, National Park Service

Informing Responders Using Gis And Gps, Deidre Mccarthy

CHAR

Hurricane Katrina devastated the Gulf Coast in August 2005 and created the single largest disaster for cultural resources that the United States has witnessed since the inception of the National Historic Preservation Act (NHPA) in 1966. Notably, the NHPA created the National Register of Historic Places, our nation’s catalog of important cultural resources. The NHPA also stipulates that any federal undertaking which may adversely affect National Register eligible resources be mitigated. For the Federal Emergency Management Agency (FEMA), Katrina created the largest compliance project ever under Section 106 of the NHPA.

Although causing a great deal of damage, Katrina ...


Physoon - Radiation Detection In Various High Altitude Environments, Christopher Helmerich 2017 DePaul University

Physoon - Radiation Detection In Various High Altitude Environments, Christopher Helmerich

2017 Academic High Altitude Conference

Physoon is a high altitude ballooning payload designed and built by members of the Space Hardware Club for the purpose of comparing cosmic and terrestrial radiation from a variety of environmental conditions, including clear days, night times, solar events (eclipses, solar flares, coronal mass ejections), and thunderstorms. Over three design iterations, Physoon has flown eleven times with various combinations of Geiger counters sensors: a low energy Alpha-Beta-Gamma detector, an unshielded high-energy Beta-Gamma detector, and a shielded high-energy Beta-Gamma detector. One of these iterations successfully recovered data from high altitude during totality of the Great American Solar Eclipse. Another iteration was ...


Additional Data Via Autonomous Systems To Supplement Traditional Sparse Sources For Weather Forecasting And Atmospheric Science, Suzanne Weaver Smith 2017 University of Kentucky

Additional Data Via Autonomous Systems To Supplement Traditional Sparse Sources For Weather Forecasting And Atmospheric Science, Suzanne Weaver Smith

Commonwealth Computational Summit

No abstract provided.


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