A5037674291- Ionosphere and magnetosphere dynamics
- Atmospheric Ozone and Climate
- Solar and Space Plasma Dynamics
- Geophysics and Gravity Measurements
- Meteorological Phenomena and Simulations
- Climate variability and models
- Geomagnetism and Paleomagnetism Studies
- Astrophysics and Star Formation Studies
- Earthquake Detection and Analysis
- Spectroscopy and Laser Applications
- Ocean Waves and Remote Sensing
- Atmospheric chemistry and aerosols
- GNSS positioning and interference
- Seismic Waves and Analysis
- Astro and Planetary Science
- Atmospheric and Environmental Gas Dynamics
- Stellar, planetary, and galactic studies
- Methane Hydrates and Related Phenomena
- Planetary Science and Exploration
- Astronomy and Astrophysical Research
- Tropical and Extratropical Cyclones Research
- Molecular Spectroscopy and Structure
- Seismology and Earthquake Studies
- Atomic and Subatomic Physics Research
- Atmospheric aerosols and clouds
Br. Birkeland (Norway)
2014-2023
Norwegian University of Science and Technology
2014-2023
University of Bergen
2016-2020
University of Nottingham
1994-2017
British Antarctic Survey
2003-2012
Bureau of Meteorology
2011-2012
Northwest Research Associates
2011
Natural Environment Research Council
2003-2005
Abstract Studies of vertical and interhemispheric coupling during Sudden Stratospheric Warmings (SSWs) suggest that gravity wave (GW) momentum flux divergence plays a key role in forcing the middle atmosphere, although observational validation GW is limited. We present whole atmosphere view zonal winds from surface to 100 km January 2013 major SSW, together with observed fluxes mesopause region derived uninterrupted high‐resolution meteor radar observations an All‐Sky Interferometric Meteor...
This paper reviews recent progress toward understanding the dynamics of middle atmosphere in framework Atmospheric Dynamics Research InfraStructure Europe (ARISE) initiative. The atmosphere, integrating stratosphere and mesosphere, is a crucial region which influences tropospheric weather climate. Enhancing requires improved measurement propagation breaking planetary gravity waves originating lowest levels atmosphere. Inter-comparison studies have shown large discrepancies between...
[1] This paper describes the use of EOS Microwave Limb Sounder (MLS) data to observe field traveling planetary waves with quasi 16 day periods. This study utilizes MLS v2.2 temperature and geopotential between 1 January 2005 31 December 2008 in range 316 hPa 0.001 (approximately 8 97 km) examine these waves. Analysis demonstrates that wavefield is made up a number components westward eastward propagating s = 2 generally dominant. In Northern Hemisphere have similar magnitudes are larger than...
Using simulations with a whole-atmosphere chemistry-climate model nudged by meteorological analyses, global satellite observations of nitrogen oxide (NO) and water vapour the Sub-Millimetre Radiometer instrument (SMR), temperature Microwave Limb Sounder (MLS), as well local radar observations, this study examines recent major stratospheric sudden warming accompanied an elevated stratopause event (ESE) that occurred in January 2013. We examine dynamical processes during ESE, including role...
Using meteor wind data from the Super Dual Auroral Radar Network (SuperDARN) in Northern Hemisphere, we (1) demonstrate that migrating (Sun-synchronous) tides can be separated nonmigrating components mesosphere and lower thermosphere (MLT) region (2) use this to determine response of different semidiurnal tide (SDT) sudden stratospheric warming (SSW) conditions. The radars span a limited range latitudes around 60$^{\circ}$ N are located over nearly 180$^{\circ}$ longitude. is extracted...
Abstract. Ground-based remote sensing of atmospheric parameters is often limited to single station observations by vertical profiles at a certain geographic location. This limiting factor for investigating gravity wave dynamics as the spatial information missing, e.g., horizontal wavelength, propagation direction or intrinsic frequency. In this study, we present new retrieval algorithm multistatic meteor radar networks obtain tomographic 3-D wind fields within pre-defined domain area. The...
Abstract. The Microwave Limb Sounder (MLS) on the Aura satellite has been used to measure temperatures in stratosphere, mesosphere and lower thermosphere. data here are from August 2004 December 2010 latitudes 75° N S. temperature reveal regular presence of a westward-propagating 16-day planetary wave with zonal wavenumber 1. amplitudes maximise winter at middle high latitudes, where monthly-mean can be as large ~8 K. Significant also observed summer-time thermosphere (MLT) stratospheric...
Abstract. Zonal and meridional winds have been measured in the upper mesosphere lower thermosphere at polar latitudes using two ground-based meteor radars. One radar is located Rothera (68° S, 68° W) Antarctic has operational since February 2005. The second Esrange N, 21° E) Arctic October 1999. Both radars produced relatively continuous measurements. Here we consider measurements made up to end of 2009. are similar design conjugate geographical latitudes, making results directly comparable...
Abstract. This study investigates the effect of stratospheric sudden warmings (SSWs) on planetary wave (PW) activity in mesosphere–lower thermosphere (MLT). PW near 95 km is derived from meteor wind data using a chain eight SuperDARN radars at high northern latitudes that span longitudes 150° W to 25° E and 51 66° N. Zonal number 1 2 components were extracted meridional for years 2000–2008. The observed wintertime shows common features associated with reversals accompanying warming events....
The first application of molecular rotational contour fitting to the analysis high-resolution profiles λλ6614 and 5797 diffuse interstellar absorption bands is described. A range selected molecular, electronic transition dipole symmetries considered. It found that profile λ6614 well reproduced by a Coriolis-induced perpendicular planar oblate symmetric top molecule. Based on this result other considerations, large carbon ring molecules emerge as good candidates for carriers (possibly) λ5797...
High-resolution and high-S/N observations of the strong relatively narrow λ5797 diffuse interstellar absorption band, recorded with Ultra-High-Resolution Facility at 3.9 m Anglo-Australian Telescope 0.9 coudé feed Kitt Peak National Observatory, are reported. For selected lines sight using resolving powers up to 600,000, a remarkable degree intrinsic ultrafine structure is found within band. There exists an almost exact correspondence between in spectra toward μ Sgr, ζ Per, Oph, including...
Abstract. The coupling processes in the middle atmosphere have been a subject of intense research activity because their effects on atmospheric circulation, structure, variability, and distribution chemical constituents. In this study, day-to-day variability Aura-MLS (Microwave Limb Sounder) temperature data are used to reveal vertical interhemispheric stratosphere-mesosphere during four Northern Hemisphere winters (2004/2005–2007/2008). UKMO (United Kingdom Meteorological Office)...
Long‐period planetary wave data derived from meteor wind observations recorded over a 12‐year period with the SuperDARN radar at Halley, Antarctica, are presented and compared phase of quasi‐biennial oscillation (QBO) throughout equatorial stratosphere. Enhanced activity in Antarctic upper mesosphere is found during summer months, when QBO stratosphere westerly, late winter, easterly. These enhancements coincide reduction strength, by up to 30%, late‐winter eastward winds mesosphere. In...
An 8 year series of 965 high-resolution radiosonde soundings over Rothera (67 degrees S, 68 W) on the Antarctic Peninsula are used to study gravity wave characteristics in lower stratosphere. The energy is shown have a seasonal variation with peaks at equinoxes; largest peak around spring equinox. During winter months and extending into spring, there both an enhancement downward propagating activity reduction amount critical-level filtering upward mountain waves. horizontal propagation...
Abstract. A mesospheric front was observed with an all-sky airglow imager on the night of 9–10 July 2007 at Ferraz Station (62° S, 58° W), located King George island Antarctic Peninsula. The wave propagated from southwest to northeast a well defined and series crests behind main front. parameters were obtained via 2-D Fourier transform data providing horizontal wavelength 33 km, period 6 min, phase speed 92 m s−1. Simultaneous winds measured medium frequency (MF) radar Rothera (68° 68° W)...
As part of a collaborative program between British Antarctic Survey and Utah State University, measurements were made using an all‐sky airglow imager located at the U.K. Halley Station (76°S, 27°W) during 2000 2001 austral winter seasons from April through to early September. A co‐located imaging Doppler interferometer was utilized obtain coincident wind for total 171 wave events. This study comprises first detailed climatological investigation propagation nature (freely propagating, ducted,...
Abstract. The previously reported observation of anomalous eastward gravity wave forcing at mesopause heights around the onset January 2013 major sudden stratospheric warming (SSW) over Trondheim, Norway (63° N, 10° E), is placed in a global perspective using Microwave Limb Sounder (MLS) temperature observations from Aura satellite. It shown that this results clear cooling Trondheim about 10 km below heights. Conversely, near itself, where was measured, with meteor radar, OH airglow and MLS...
Abstract The interannual variability of the mesosphere and lower thermosphere (MLT) gravity wave momentum flux over southern midlatitudes (53.7°S) has been studied using more than 7 years meteor radar observations at Río Grande, Argentina. A modulation, with periods similar to that equatorial stratospheric quasi‐biennial oscillation (QBO), is observed in vertical zonal as well meridional momentum. QBO signal largest component during summer phase 50 hPa (∼21 km). relation between modulation...
Mesospheric temperatures derived from spectroscopic measurements of the hydroxyl (OH) nightglow have been observed Rothera (67.6°S, 68.1°W) and Halley (75.6°S, 26.6°W) stations in Antarctica during 2002 austral winter season. In addition to normal seasonal changes, at both sites, separated by 1658 km, showed several simultaneous shifts temperature between 10 20 K. These changes abruptly occurred space 2–3 days lasted for days. rapid variations were associated with large swings meridional...
Abstract. Images of mesospheric airglow and radar-wind measurements have been combined to estimate the difference in vertical flux horizontal momentum carried by high-frequency gravity waves over two dissimilar Antarctic stations. Rothera (67° S, 68° W) is situated mountains Peninsula near edge wintertime polar vortex. In contrast, Halley (76° 27° W), some 1658 km southeast, located on an ice sheet at Plateau deep within vortex during winter. The cross-correlation coefficients between wind...