Oceanography and Atmospheric Sciences and Meteorology Commons^™

An Advanced Mesospheric Temperature Mapper For High-Latitude Airglow Studies, Pierre-Dominique Pautet, Michael J. Taylor, William R. Pendleton Jr., Yucheng Zhao, Tao Yuan, R. Esplin, D. Mclain

Publications

Over the past 60 years, ground-based remote sensing measurements of the Earth’s mesospheric temperature have been performed using the nighttime hydroxyl (OH) emission, which originates at an altitude of ∼87  km∼87  km. Several types of instruments have been employed to date: spectrometers, Fabry–Perot or Michelson interferometers, scanning-radiometers, and more recently temperature mappers. Most of them measure the mesospheric temperature in a few sample directions and/or with a limited temporal resolution, restricting their research capabilities to the investigation of larger-scale perturbations such as inertial waves, tides, or planetary waves. The Advanced Mesospheric Temperature Mapper (AMTM) is a novel infrared digital imaging …

Adjusted Tornado Probabilities, Holly M. Widen, James B. Elsner, Cameron Amrine, Rizalino B. Cruz, Erik Fraza, Laura Michaels, Loury Migliorelli, Brendan Mulholland, Michael Patterson, Sarah Strazzo, Guang Xing

Publications

Tornado occurrence rates computed from the available reports are biased low relative to the unknown true rates. To correct for this low bias, the authors demonstrate a method to estimate the annual probability of being struck by a tornado that uses the average report density estimated as a function of distance from nearest city/town center. The method is demonstrated on Kansas and then applied to 15 other tornado-prone states from Nebraska to Tennessee. States are ranked according to their adjusted tornado rate and comparisons are made with raw rates published elsewhere. The adjusted rates, expressed as return periods, arestates, including …

Wave Heating And Jeans Escape In The Martian Upper Atmosphere, R. L. Walterscheid, Michael P. Hickey Ph.D., G. Schubert

Publications

Gusty flow over rough terrain is likely to be a significant source of fast gravity waves and acoustic waves in the atmosphere of Mars, as it is in Earth’s atmosphere. Accordingly, we have used a numerical model to study the dissipation in the thermosphere and exosphere of Mars of upward-propagating fast gravity waves and acoustic waves. Model simulations are performed for a range of wave periods and horizontal wavelengths. Wave amplitudes are constrained by the Mars Global Surveyor and Mars Odyssey aerobraking data, and gravity wave phase velocities are limited by occultation data. Dissipating gravity waves heat some regions of …

Observed Versus Gcm-Generated Local Tropical Cyclone Frequency: Comparisons Using A Spatial Lattice, Sarah Strazzo, Daniel J. Halperin, James Elsner, Tim Larow, Ming Zhao

Publications

Of broad scientific and public interest is the reliability of global climate models (GCMs) to simulate future regional and local tropical cyclone (TC) occurrences. Atmospheric GCMs are now able to generate vortices resembling actual TCs, but questions remain about their fidelity to observed TCs. Here the authors demonstrate a spatial lattice approach for comparing actual with simulated TC occurrences regionally using observed TCs from the International Best Track Archive for Climate Stewardship (IBTrACS) dataset and GCM-generated TCs from the Geophysical Fluid Dynamics Laboratory (GFDL) High Resolution Atmospheric Model (HiRAM) and Florida State University (FSU) Center for Ocean–Atmospheric Prediction Studies (COAPS) …

Ionospheric Signatures Of Acoustic Waves Generated By Transient Tropospheric Forcing, M. D. Zettergren, J. B. Snively

Publications

Acoustic waves generated by tropospheric sources may attain significant amplitudes in the thermosphere and overlying ionosphere. Although they are weak precursors to gravity waves in the mesosphere below, acoustic waves may achieve temperature and vertical wind perturbations on the order of approximately tens of Kelvin and m/s throughout the E and F regions. Their perturbations to total electron content are predicted to be detectable by groundbased radar and GPS receivers; they also drive field-aligned currents that may be detectable in situ via magnetometers. Although transient and short lived, ionospheric signatures of acoustic waves may provide new and quantitative insight into …

A Meteorological Analysis Of Important Contributions To The 1999-2005 Canadian Prairie Drought, Lisa M. Hryciw, Eyad H. Atallah, Shawn M. Milrad, John R. Gyakum

Publications

Drought is a complex natural hazard that is endemic to the Canadian prairies. The 1999–2005 Canadian prairie drought, which had great socioeconomic impacts, was meteorologically unique in that it did not conform to the traditional persistent positive Pacific–North American (PNA) pattern and west coast ridging paradigm normally associated with prairie drought. The purpose of this study is to diagnose the unique synoptic-scale mechanisms responsible for modulating subsidence during this drought. Using 30-day running means of the percent of normal precipitation from station data, key severe dry periods during 1999–2005 are identified. Analysis of the mean fields from reanalysis data shows …

Numerical And Statistical Evidence For Long-Range Ducted Gravity Wave Propagation Over Halley, Antarctica, J. B. Snively, K. Nielsen, M. P. Hickey, C. J. Heale, M. J. Taylor, T. Moffat-Griffin

Publications

Abundant short-period, small-scale gravity waves have been identified in the mesosphere and lower thermosphere over Halley, Antarctica, via ground-based airglow image data. Although many are observed as freely propagating at the heights of the airglow layers, new results under modeled conditions reveal that a significant fraction of these waves may be subject to reflections at altitudes above and below.The waves may at times be trapped within broad thermal ducts, spanning from the tropopause or stratopause to the base of the thermosphere (~140 km), which may facilitate long-range propagation (~1000s of km) under favorable wind conditions.

Mesospheric Hydroxyl Airglow Signatures Of Acoustic And Gravity Waves Generated By Transient Tropospheric Forcing, J. B. Snively

Publications

"Numerical model results demonstrate that acoustic waves generated by tropospheric sources may produce cylindrical “concentric ring” signatures in the mesospheric hydroxyl airglow layer. They may arrive as precursors to upward propagating gravity waves, generated simultaneously by the same sources, and produce strong temperature perturbations in the thermosphere above. Transient and short-lived, the acoustic wave airglow intensity and temperature signatures are predicted to be detectable by ground-based airglow imaging systems and may provide new insight into the forcing of the upper atmosphere from below."--From publisher's website.

Synoptic-Scale Precursors, Characteristics And Typing Of Nocturnal Mesoscale Convective Complexes In The Great Plains, Shawn M. Milrad, Cailee M. Kelly

Publications

Mesoscale convective complexes (MCCs) occur frequently during the warm season in the central U.S. and can produce flooding rains, hail and tornadoes. Previous work has found that the synoptic-scale environment can greatly affect, and be affected by, the development and maintenance of MCCs. Ninetytwo MCC cases from 2006–2011 are manually identified using infrared satellite imagery and partitioned into three types (upstream trough, zonal and ridge) using a unique manual synoptic typing based on 500- hPa height patterns. Upstream trough cases feature an amplified longwave 500-hPa trough upstream of the MCC genesis region (GR), while the 500-hPa flow is relatively flat …

Sensitivity Of Limiting Hurricane Intensity To Sst In The Atlantic From Observations And Gcms, James Elsner, Sarah Strazzo, Thomas H. Jagger, Timothy Larow, Ming Zhao

Publications

No abstract provided.

Frequency, Intensity, And Sensitivity To Sea Surface Temperature Of North Atlantic Tropical Cyclones In Best-Track And Simulated Data, Sarah Strazzo, James B. Elsner, Jill C. Trepanier, Kerry A. Emanuel

Publications

Synthetic hurricane track data generated from a downscaling approach are compared to best-track (observed) data to analyze differences in regional frequency, intensity, and sensitivity of limiting intensity to sea surface temperature (SST). Overall, the spatial distributions of observed and simulated hurricane counts match well, although there are relatively fewer synthetic storms in the eastern quarter of the basin. Additionally, regions of intense synthetic hurricanes tend to coincide with regions of intense observed hurricanes. The sensitivity of limiting hurricane intensity to SST computed from synthetic data is slightly lower than sensitivity computed from observed data (5.561.31 m s21 (standard error, SE) …

The Optical Manifestation Of Dispersive Field‐Aligned Bursts In Auroral Breakup Arcs, H. Dahlgren, J. L. Semeter, R. A. Marshall, M. Zettergren

Publications

High‐resolution optical observations of a substorm expansion show dynamic auroral rays with surges of luminosity traveling up the magnetic field lines. Observed in ground‐based imagers, this phenomenon has been termed auroral flames, whereas the rocket signatures of the corresponding energy dispersions are more commonly known as field‐aligned bursts. In this paper, observations of auroral flames obtained at 50 frames/s with a scientific‐grade Complementary Metal Oxide Semiconductor (CMOS) sensor (30° × 30° field of view, 30 m resolution at 120 km) are used to provide insight into the nature of the precipitating electrons similar to high‐resolution particle detectors. Thanks to the …

Tips From The Board Of Broadcast Meteorology For Gaining The Certified Broadcast Meteorologist (Cbm) Designation, Rob Eicher

Publications

These notes are intended to maximize the likelihood that you will pass the AMS CBM evaluation on your first attempt. Typically half of first-time applicants pass the evaluation.

Precipitation Modulation By The Saint Lawrence River Valley In Association With Transitioning Tropical Cyclones, Shawn M. Milrad, Eyad H. Atallah, John R. Gyakum

Publications

The St. Lawrence River valley (SLRV) is an important orographic feature in eastern Canada that can affect surface wind patterns and contribute to locally higher amounts of precipitation. The impact of the SLRV on precipitation distributions associated with transitioning, or transitioned, tropical cyclones that approached the region is assessed. Such cases can result in heavy precipitation during the warm season, as during the transition of Hurricane Ike (2008). Thirty-eight tropical cyclones tracked within 500 km of the SLRV from 1979 to 2011. Utilizing the National Centers for Environmental Prediction (NCEP) North American Regional Reanalysis (NARR), 19 of the 38 cases …

A Thermodynamic Analysis Of An Intense North American Arctic Air Mass, Jessica K. Turner, John Gyakum, Shawn M. Milrad

Publications

Northwestern Canada is a genesis region of arctic air masses often considered to be formed primarily through radiative processes. However, the details of their life cycle are poorly understood. This paper examines the formation, maintenance, and dissipation of an intense and long-lived arctic air mass, using a thermodynamic budget analysis.

The airmass formation is characterized by a deep-layer, multistage process that begins with snow falling into a nascent air mass. Radiative cooling from cloud tops begins the process. After the snow abates and clear skies are observed, the surface temperature drops rapidly, aided by the high emissivity of fresh snow …

Multi-Instrument Comparisons Of D-Region Plasma Measurements, M. Friedrich, K. M. Torkar, U. P. Hoppe, T. A. Bekkeng, A. Barjatya, M. Rapp

Publications

The ECOMA (Existence and Charge state Of Meteoric dust grains in the middle Atmosphere) series of sounding rocket flights consisted of nine flights with almost identical payload design and flight characteristics. All flights carried a radio wave propagation experiment together with a variety of plasma probes. Three of these measured electron densities, two ion densities. The rockets were all launched from the Andøya Rocket Range, Norway, in four campaigns between 2006 and 2010. Emphasis is on the final three flights from 2010 where the payloads were equipped with four instruments capable of measuring plasma densities in situ, among them a …

Elevated Electron Temperatures Around Twin Sporadic E Layers At Low Latitude: Observations And The Case For A Plausible Link To Currents Parallel To The Geomagnetic Field, A. Barjatya, J. P. St. Maurice, C. M. Swenson

Publications

We present data from nighttime sounding rocket flights in the low latitude E region. The payloads carried a sweeping Langmuir probe, a plasma impedance probe, and electric field probes. A detailed examination of the plasma density, temperature, and electric field measurements show two strong sporadic E (Es) layers with very high electron temperatures (∼1000 K) on each side of the upper layer. The lower layer was consistent with the presence of a strong zonal neutral wind shear. The upper layer was strongly influenced by the presence of a strongly negative vertical electric field, with zonal winds and …

Histological Changes In The Target Organs Of Channa Punctatus After Exposure To Anthraquinone Vat Dyes, Rajee Olaganathan, Jamila Patterson

Publications

The present study is an attempt on histopathology of gill, liver, kidney and intestine of Channa punctatus after exposure to sublethal concentrations of anthraquinone vat dyes viz., vat blue 4 and vat green 1. The dyes has been found to produce several damages in the vital organs of C. punctatus leading to various lesions like extensive lamellar hypertrophy with some proliferation at the base of secondary lamellae and hyperplasia of intercellular epithelial cells in the gill; fat accumulation, hepatic necrosis, aggregation of polymorphonuclear leucocytes, hepatocellular degeneration and aggregation of hepatocytes in liver; while in kidney it caused hyperplastic of the …

An Intense Traveling Airglow Front In The Upper Mesosphere–Lower Thermosphere With Characteristics Of A Bore Observed Over Alice Springs, Australia, During A Strong 2 Day Wave Episode, R. L. Walterscheid, J. H. Hecht, L. J. Galinas, Michael P. Hickey Ph.D., I. M. Reid

Publications

The Aerospace Corporation’s Nightglow Imager observed a large step function change in airglow in the form of a traveling front in the OH Meinel (OHM) and O2 atmospheric (O2A) airglow emissions over Alice Springs, Australia, on 2 February 2003. The front exhibited nearly a factor of 2 stepwise increase in the OHM brightness and a stepwise decrease in the O2A brightness. There was significant (~25 K) cooling behind the airglow fronts. The OHM airglow brightness behind the front was among the brightest for Alice Springs that we have measured in 7 years of observations. The event was associated with a …

Sensitivity Of Limiting Hurricane Intensity To Ocean Warmth, James B. Elsner, Sarah Strazzo, Jill C. Trepanier, Thomas H. Jagger

Publications

No abstract provided.

Biodegradation Of Textile Dye Anthraquinone Vat Blue 4 By Pseudomonas Aeruginosa, Rajee Olaganathan, Jamila Patterson

Publications

Uncontaminated and Vat blue 4 contaminated soil were screened for heterotrophic bacterial population and the bacterial density were found to be 19.3 X 104 and 5.5 X 104 CFU/gm respectively. The bacterial genera of dye contaminated soil was dominated by Pseudomonas sp. (32.5 %) followed by Bacillus sp. (27.5 %), Aeromonas sp. (15.0 %), Micrococcus sp. (12.5 %) and Achromobacter sp. (12.5 %). The optimum inoculums load, pH and temperature were found to be 5%, 7 and 35oC respectively. The initial pH of the effluent prepared using Vat Blue 4 was 8.5. The free cells of P. aeruginosa reduced the …

Ionospheric Signatures Of Tohoku-Oki Tsunami Of March 11, 2011: Model Comparisons Near The Epicenter, David A. Galvan, Attila Komjathy, Michael P. Hickey, Philip Stephens, Jonathan Snively, Y. Tony Song, Mark D. Butala, Anthony J. Mannucci

Publications

We observe ionospheric perturbations caused by the Tohoku earthquake and tsunami of March 11, 2011. Perturbations near the epicenter were found in measurements of ionospheric total electron content (TEC) from 1198 GPS receivers in the Japanese GEONET network. For the first time for this event, we compare these observations with the estimated magnitude and speed of a tsunami-driven atmospheric gravity wave, using an atmosphere-ionosphere-coupling model and a tsunami model of sea-surface height, respectively. Traveling ionospheric disturbances (TIDs) were observed moving away from the epicenter at approximate speeds of 3400 m/s, 1000 m/s and 200–300 m/s, consistent with Rayleigh waves, acoustic …

Ionospheric Plasma Transport And Loss In Auroral Downward Current Regions, M. Zettergren, J. L. Semeter

Publications

A detailed study of the effects of auroral current systems on thermal ionospheric plasma transport and loss is conducted using a new ionospheric model. The mathematical formulation of the model is a variation on the 5‐moment approximation which describes the temporal evolution of density, drift, and temperature for five different ion species in two spatial dimensions. The fluid system is closed through a 2‐D electrostatic treatment of the auroral currents. This model is used to examine the interplay between ion heating, perpendicular transport, molecular ion generation, and type‐1 ion upflows in a self‐consistent way for the first time. Simulations confirm …

Gravity Wave Propagation In A Diffusively Separated Gas: Effects On The Total Gas, Michael P. Hickey Ph.D., R. L. Walterscheid

Publications

We present a full-wave model that simulates acoustic-gravity wave propagation in a binary-gas mixture of atomic oxygen and molecular nitrogen, including molecular viscosity and thermal conductivity appropriately partitioned between the two gases. Compositional effects include the collisional transfer of heat and momentum by mutual diffusion between the two gases. An important result of compositional effects is that the velocity and temperature summed over species can be significantly different from the results of one-gas models with the same height dependent mean molecular weight (M(z)). We compare the results of our binary-gas model to two one-gas full-wave models: one where M is …

Synoptic-Scale Analysis Of Freezing Rain Events In Montreal, Quebec, Canada, Gina M. Ressler, Shawn M. Milrad, Eyad H. Atallah, John R. Gyakum

Publications

Freezing rain is a major environmental hazard that is especially common along the St. Lawrence River valley (SLRV) in southern Quebec, Canada. For large cities such as Montreal, severe events can have a devastating effect on people, property, and commerce. In this study, a composite analysis of 46 long-duration events for the period 1979–2008 is presented to identify key synoptic-scale structures and precursors of Montreal freezing rain events. Based on the observed structures of the 500-hPa heights, these events are manually partitioned into three types—west, central, and east—depending on the location and tilt of the 500-hPa trough axis. West events …

Synoptic-Scale Environments Conducive To Orographic Impacts On Cold-Season Surface Wind Regimes At Montreal, Quebec, Alissa Razy, Shawn M. Milrad, Eyad H, Atallah, John R. Gyakum

Publications

Orographic wind channeling, defined as dynamically and thermally induced processes that force wind to blow along the axis of a valley, is a common occurrence along the St. Lawrence River Valley (SLRV) in Quebec, Canada, and produces substantial observed weather impacts at stations along the valley, including Montreal (CYUL). Cold-season observed north-northeast (n = 55) and south-southeast (n = 16) surface wind events at CYUL are identified from 1979 to 2002. The authors partition the north-northeast wind events into four groups using manual synoptic typing. Types A and D (“inland cyclone” and “northwestern cyclone”) are associated with strong lower-tropospheric geostrophic …

Gravity-Wave-Induced Variations In Exothermic Heating In The Low-Latitude, Equinox Mesophere And Lower Thermosphere Region, Michael P. Hickey Ph.D., Tai-Yin Huang

Publications

We investigate gravity-wave-induced variations in exothermic heating in the OH nightglow region at a latitude of 18° in the Northern and Southern Hemispheres during March. An OH nightglow chemistry model with gravity wavefields from a spectral full-wave model is used for the investigation. Our simulation results show that the wave packet induces a large secular increase in the number densities of the minor species involved in the OH chemistry, a 50% increase in O3, 42% in O, and 29% in OH (v= 8), and the ultimate driver for these increases is the wave-driven downward transport of O. We find that …

Disparities In Weather Education Across Professional Flight Baccalaureate Degree Programs, Thomas A. Guinn, Krista M. Rader, Thomas A. Guinn

Publications

The required meteorology coursework for 22 accredited professional flight baccalaureate degree programs was examined and compared. Significant differences were noted in both the number of required meteorology courses as well as the number of required meteorology credit hours. While all programs required at least one three-credit meteorology course, not all programs required an aviation-specific meteorology course. In addition to the required number of meteorology courses and credit hours, topics within the aviation-specific meteorology courses were also examined. The study showed the topics of “flight hazards” and “aviation weather reports and charts” were identified most frequently in course descriptions, followed third …

Gravity Wave Heating And Cooling Of The Thermosphere: Sensible Heat Flux And Viscous Flux Of Kinetic Energy, Michael P. Hickey Ph.D., R. L. Walterscheid, G. Schubert

Publications

Total wave heating is the sum of the convergence of the sensible heat flux and the divergence of the viscous flux of wave kinetic energy. Numerical simulations, using a full-wave model of the viscous damping of atmospheric gravity waves propagating in a nonisothermal atmosphere, are carried out to explore the relative contributions of these sources of wave heating as a function of wave properties and altitude. It is shown that the sensible heat flux always dominates in the lower thermosphere, giving a lower region of heating and an upper stronger region of cooling. The heating due to the divergence of …

Particle‐In‐Cell Simulation Of Incoherent Scatter Radar Spectral Distortions Related To Beam‐Plasma Interactions In The Auroral Ionosphere, M. A. Diaz, M. Oppenheim, J. L. Semeter, M. Zettergren

Publications

An electrostatic parallel particle‐in‐cell (EPPIC) code that allows for particle beam injections and multiple boundary conditions is used to investigate the beam‐plasma interaction and its manifestations in the incoherent scatter (IS) spectrum. Specifically, the code is used to investigate anomalous enhancements in the ion acoustic line through the destabilization of the plasma by injection (or precipitation) of low‐energy electron beams. This enhancement of the ion acoustic line is a form of IS distortion commonly observed in the vicinity of auroral arcs called the naturally enhanced ion‐acoustic line (NEIAL). Simulations confirm the parametric decay of Langmuir waves as a plausible mechanism, …