A5081574665- Ionosphere and magnetosphere dynamics
- Atmospheric Ozone and Climate
- Planetary Science and Exploration
- Solar and Space Plasma Dynamics
- Astro and Planetary Science
- Earthquake Detection and Analysis
- Geophysics and Gravity Measurements
- GNSS positioning and interference
- Geomagnetism and Paleomagnetism Studies
- Meteorological Phenomena and Simulations
- Seismic Waves and Analysis
- Atmospheric aerosols and clouds
- Atmospheric chemistry and aerosols
- Space Exploration and Technology
- Methane Hydrates and Related Phenomena
- Scientific Research and Discoveries
- Ocean Waves and Remote Sensing
- Electromagnetic Simulation and Numerical Methods
- Electromagnetic Compatibility and Measurements
- Radio Wave Propagation Studies
- Microwave Imaging and Scattering Analysis
- Cultural Differences and Values
- Aeolian processes and effects
- Social and Intergroup Psychology
- Space Satellite Systems and Control
Boston University
2012-2023
Lawrence Livermore National Laboratory
2013
University of Utah
2011
University of Canterbury
1991
Scripps Institution of Oceanography
1979
United States Army Medical Command
1968
Abstract The Deep Propagating Gravity Wave Experiment (DEEPWAVE) was designed to quantify gravity wave (GW) dynamics and effects from orographic other sources regions of dissipation at high altitudes. core DEEPWAVE field phase took place May through July 2014 using a comprehensive suite airborne ground-based instruments providing measurements Earth’s surface ∼100 km. Austral winter chosen observe deep GW propagation based on South Island, New Zealand, provide access the Zealand Tasmanian...
Significance As an unforeseen windfall of its high sensitivity, the Day/Night Band (DNB) low-light visible sensor carried on Suomi satellite enables global detection gravity waves in upper atmosphere at unprecedented subkilometric detail. On moonless nights, observations provide all-weather viewing as they modulate nightglow layer located near mesopause. These are launched by a variety mechanisms ranging from orography to convection, intensifying fronts, and seismic volcanic events. Wave...
This paper describes a new stochastic finite difference time domain (S-FDTD) method for calculating the variance in electromagnetic fields caused by variability or uncertainty electrical properties of materials model. Details 1D derivation using truncated Taylor series approximations are given. The S-FDTD analysis is then compared to Monte Carlo bioelectromagnetic example. accuracy controlled cross correlations and properties. In this paper, we able bound 1 (overestimate) reflection...
On-orbit firings of both liquid and solid rocket motors provide localized disturbances to the plasma in upper atmosphere. Large amounts energy are deposited ionosphere form expanding exhaust vapors which change composition flow velocity. Charge exchange between neutral molecules background ions (mainly O <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> ) yields energetic ion beams. The rapidly moving pickup excite instabilities yield...
Imaging measurements of a bright wave event in the nighttime mesosphere were made on 14 November 1999 at two sites separated by over 500 km southwestern United States. The was characterized sharp onset series extensive wavefronts that propagated across entire sky. waves easily visible to naked eye, and observed for least 5 hours. using three wide‐angle imaging systems located Boston University field station McDonald Observatory (MDO), Fort Davis, Texas, Starfire Optical Range (SOR),...
We report on the first imaging observations of stationary mesospheric gravity‐waves in three nightglow emissions OH (695–1050 nm), Na (589.3 nm) and O( 1 S) (557.7 nm). The waves were observed all‐sky images at El Leoncito Observatory (ELO), Argentina (31.8°S, 69.3°W), during period 1–8 July 2008. Over course each night, band‐like wave features exhibited a zero or near‐zero horizontal phase speed had lifetimes several hours. These factors, coupled with winds measured locally, orientation to...
Night‐time measurements using a bare CCD all‐sky imaging system have detected the presence of an extensive region neutral sodium emission (589.1 nm) in direction anti‐solar/lunar points. The was observed to occur during nights 21–22 August and 18–20 November, 1998 UT, centered on new Moon period. is most likely source sodium, making this first detection lunar tail out distance hundreds radii. greater brightness feature 19 November attributed Leonid meteor shower which peaked 17 1998, less...
Ionospheric physics deals with the basic structure and variability of plasma within upper atmospheres Earth planets. Comparative studies foster both exploration synthesis diverse settings. In this paper we examine observations ionospheric profiles on Mars obtained 9–27 March 1999 by radio science experiment onboard Global Surveyor satellite, compare their day‐to‐day same‐day Earth. Using photochemical‐equilibrium arguments applicable to peak electron density layer E‐layer Earth, find...
Wave‐like disturbances in electron density n e have been observed the thermosphere above Arecibo Observatory, Puerto Rico throughout its 45 year history. However, only recently has it become evident that these waves are continuously present thermosphere. The wave characteristics fairly constant between day and night from season to season. High‐resolution measurements obtained by applying coded long‐pulse radar technique photoelectron‐enhanced Langmuir presented. These new observations...
Abstract All‐sky images obtained with the Boston University all‐sky imaging system located at Mount John Observatory, New Zealand (43.98°S, 170.42°E) show clear evidence of dynamic coupling between mesosphere and thermosphere. Gravity wave (GW) breaking events in upper altitudes (z) 80 to 100 km were observed 557.7 nm emission on evening 4 March 2009 from 08:40 13:50 UT. During this time, unusual oppositely propagating weak northwestward (NW‐ward) strong southeastward (SE‐ward) GWs...
Abstract Observations of a pair mesospheric bore disturbances that propagated through the nighttime mesosphere over Europe are presented. The observations were made at Padua Observatory, Asiago (45.9°N, 11.5°E), by Boston University all‐sky imager on 11 March 2013. bores appeared northwest horizon, approximately 30 min apart, and toward southeast. Using additional satellite radar data, we present evidence indicating originated in from single, larger‐scale disturbance propagating mesopause...
During June and July 2002, a 30‐MHz imaging coherent scatter radar was installed operated on the island of St. Croix, to view E region ionosphere above Arecibo, Puerto Rico. observing period, 10 events with discernible quasiperiodic echo structure were observed radar. In six those events, simultaneous measurements made Arecibo 430‐MHz incoherent The allows us locate track structures within volume illuminated by transmitter, which shows that are generally aligned along wavefronts. A slight...
Abstract Although mountain waves (MWs) are thought to be a ubiquitous feature of the wintertime southern Andes stratosphere, it was not known whether these propagated up mesopause region until Smith et al. (2009) confirmed their presence via airglow observations. The new Lidar Observatory at Cerro Pachon in Chile provided opportunity for further study waves. Since MWs have near‐zero phase speed, and zero wind lines often occur winter upper mesosphere (80 100 km altitude) due reversal zonal...
Abstract A remarkable, large‐amplitude, mountain wave (MW) breaking event was observed on the night of 21 June 2014 by ground‐based optical instruments operated New Zealand South Island during Deep Propagating Gravity Wave Experiment (DEEPWAVE). Concurrent measurements MW structures, amplitudes, and background environment were made using an Advanced Mesospheric Temperature Mapper, a Rayleigh Lidar, All‐Sky Imager, Fabry‐Perot Interferometer. The primarily in OH airglow emission layer at...
Optical detections of short‐period quasi‐monochromatic gravity waves in the mesospheric nightglow emissions OH (695–950 nm), O (557.7 and Na (589.3 nm) have been obtained for first time from Millstone Hill, Massachusetts (42.6°N, 71.5°W). Using a new all‐sky bare charge‐coupled device (CCD) imaging system at this subauroral site, we 12 nights observations during period February 1 to July 21, 1998. Wave structure was observed ∼55% total observing time, 35 events were identified analyzed. Two...
Abstract. Thermospheric and mesospheric structures are studied using an all-sky imager located at El Leoncito, Argentina (31.8° S, 69.3° W, –18° mag lat). This site has relatively high geographic latitude for a location under the crest of equatorial ionization anomaly (EIA), thus observations can be used to study intrusion several processes into midlatitude domain. In addition, it conjugate point close field view our companion Arecibo, PR, allowing inter-hemispheric effects. Four types...
Abstract We report on imaging measurements of thermospheric gravity wave signatures in 630 nm and 557.7 nightglow that suggest an association with the M = 9 Tohoku (Japan) earthquake 11 March 2011. The propagating waves were recorded all‐sky images at El Leoncito Observatory, Argentina (31.8°S, 69.3°W), which is located 17,080 km from epicenter, almost global antipodal point.
A region of non‐terrestrial sodium emission seen in the sky on nights November 18–20, 1998, has been interpreted as Moon's distant tail, possibly enhanced by micrometeor impact vaporization lunar regolith Leonid meteor shower. We show that location and morphology spot can be explained standard steady‐state models atmosphere. Moreover, using a new time‐dependent simulation atmosphere, we find Na escape rate from Moon increased to 2 or 3 times its normal level during most intense period 1998...
Major geomagnetic storms produce dramatic gradients in the ionosphere's total electron content (TEC) that cause errors GPS‐dependent navigation systems, such as those used by U. S. Coast Guard and Federal Aviation Administration. Here we describe first use of GPS signals to detect large‐scale TEC very similar found during ionospheric but produced instead exhaust gases a large Titan rocket launched from Kennedy Space Center. The severe perturbations 30 April 2005, observed simultaneously...
Trans‐ionospheric radio propagation effects resulting in ranging errors are examined for a potential orbital network of communications and navigational satellites at Mars. Using recent results from the science experiment on board Mars Global Surveyor (MGS) spacecraft photochemical model Mars' ionosphere, we study total electron content (TEC) to investigate how its latitude, local time, solar cycle patterns would contribute positioning planet. In addition, examine relationship between TEC...