scholarly journals Comment on "Investigation of Arctic middle-atmospheric dynamics using 3 years of H2O and O3 measurements from microwave radiometers at Ny-Ålesund"

2019 ◽  
Author(s):  
Anonymous
Keyword(s):  
Atmospheric Dynamics ◽  
Middle Atmospheric Dynamics ◽  
Microwave Radiometers

scholarly journals Investigation of Arctic middle-atmospheric dynamics using 3 years of H<sub>2</sub>O and O<sub>3</sub> measurements from microwave radiometers at Ny-Ålesund

2019 ◽  
Author(s):  
Franziska Schranz ◽  
Brigitte Tschanz ◽  
Rolf Rüfenacht ◽  
Klemens Hocke ◽  
Mathias Palm ◽  
...  
Keyword(s):  
Water Vapour ◽  
Middle Atmosphere ◽  
Microwave Radiometer ◽  
Polar Vortex ◽  
The Arctic ◽  
High Time Resolution ◽  
Middle Atmospheric Dynamics ◽  
Wind Profiles ◽  
Microwave Radiometers

Abstract. We use 3 years of water vapour and ozone measurements to analyse dynamical events in the polar middle atmosphere such as sudden stratospheric warmings (SSW), polar vortex shifts, water vapour descent rates and periodicities. The measurements were performed with the two ground-based microwave radiometers MIAWARA-C and GROMOS-C which are co-located at the AWIPEV research base at Ny-Ålesund, Svalbard (79° N, 12° E) since September 2015. The almost continuous datasets of water vapour and ozone are characterised by a high time resolution in the order of hours. A thorough intercomparison of these datasets with models and measurements from satellite, ground-based and in-situ instruments was performed. In the upper stratosphere and lower mesosphere the MIAWARA-C profiles agree within 5 % with SD-WACCM simulations and ACE-FTS measurements whereas AuraMLS measurements show an average offset of 10–15 % depending on altitude but constant in time. Stratospheric GROMOS-C profiles are within 5 % of the satellite instruments AuraMLS and ACE-FTS and the ground-based microwave radiometer OZORAM which is also located at Ny-Ålesund. During these first three years of the measurement campaign typical phenomena of the Arctic middle atmosphere took place and we analysed their signatures in the water vapour and ozone datasets. Inside of the polar vortex in autumn we found the descent rate of mesospheric water vapour to be 435 m/day on average. In early 2017 distinct increases in mesospheric water vapour of about 2 ppm were observed when the polar vortex was displaced and midlatitude air was brought to Ny-Ålesund. Two major sudden stratospheric warmings took place in March 2016 and February 2018 where ozone enhancements of up to 4 ppm were observed. The zonal wind reversals accompanying a major SSW were captured in the GROMOS-C wind profiles which are retrieved from the ozone spectra. After the SSW in February 2018 the polar vortex re-established and the water vapour descent rate in the mesosphere was 355 m/day. In the water vapour and ozone time series signatures of atmospheric waves with periods close to 2, 5, 10 and 16 days were found.

scholarly journals Toward an Improved Representation of Middle Atmospheric Dynamics Thanks to the ARISE Project

2017 ◽  
Vol 39 (2) ◽  
pp. 171-225 ◽  
Author(s):  
E. Blanc ◽  
L. Ceranna ◽  
A. Hauchecorne ◽  
A. Charlton-Perez ◽  
E. Marchetti ◽  
...  
Keyword(s):  
Atmospheric Dynamics ◽  
Middle Atmospheric Dynamics

scholarly journals A D-region conductivity model from EISCAT VHF measurements

2002 ◽  
Vol 20 (9) ◽  
pp. 1439-1445
Author(s):  
K. Schlegel ◽  
M. Füllekrug
Keyword(s):  
Atmospheric Model ◽  
Atmospheric Dynamics ◽  
Vhf Radar ◽  
Height Range ◽  
Schumann Resonances ◽  
Middle Latitudes ◽  
Modeling And Forecasting ◽  
D Region ◽  
Middle Atmospheric Dynamics ◽  
Electron Density Profiles

Abstract. An easy-to-use model to evaluate conductivities at high and middle latitudes in the height range 70–100 km is presented. It is based on electron density profiles obtained with the EISCAT VHF radar during 11 years and on the neutral atmospheric model MSIS95. The model uses solar zenith angle, geomagnetic activity and season as input parameters. It was mainly constructed to study the properties of Schumann resonances that depend on such conductivity profiles.Key words. Meteorology and atmospheric dynamics (middle atmospheric dynamics) – Ionosphere (modeling and forecasting; ionosphere-atmosphere interaction)

scholarly journals <i>Letter to the Editor:</i> A strange cloud in the Arctic summer stratosphere 1998 above Esrange (68°N), Sweden

2000 ◽  
Vol 18 (4) ◽  
pp. 505-509 ◽  
Author(s):  
J. Siebert ◽  
C. Timmis ◽  
G. Vaughan ◽  
K. H. Fricke
Keyword(s):  
Potential Temperature ◽  
Atmospheric Dynamics ◽  
Atmospheric Composition ◽  
The Arctic ◽  
Back Trajectory ◽  
Eastern Canada ◽  
Composition And Structure ◽  
Middle Atmospheric Dynamics ◽  
Thin Cloud ◽  
The University

Abstract. When the University of Bonn lidar on the Esrange (68°N, 21°E), Sweden, was switched on in the evening of July 18, 1998, a geometrically and optically thin cloud layer was present near 14 km altitude or 400 K potential temperature, where it persisted for two hours. The tropopause altitude was 4 km below the cloud altitude. The cloud particles depolarized the lidar returns, thus must they have been aspherical and hence solid. Atmospheric temperatures near 230 K were approximately 40 K too high to support ice particles at stratospheric water vapour pressures of a few ppmv. The isentropic back trajectory on 400 K showed the air parcels to have stayed clear of active major rocket launch sites. The air parcels at 400 K had traveled from the Aleutians across Canada and the Atlantic Ocean arriving above central Europe and then turned northward to pass over above the lidar station. Parcels at levels at ±25 K from 400 K had come from the pole and joined the 400 K trajectory path above eastern Canada. Apparently the cloud existed in a filament of air with an origin different from those filaments both above and below. Possibly the 400 K level air parcels had carried soot particles from forest wild fires in northern Canada or volcanic ash from the eruption of the Korovin Volcano in the Aleutian Islands.Key words: Atmospheric composition and structure (aerosols and particles; biosphere-atmosphere interactions) · Meteorology and atmospheric dynamics (middle atmospheric dynamics)

scholarly journals Mean winds of the mesosphere and lower thermosphere at 52° N in the period 1988–2000

2002 ◽  
Vol 20 (1) ◽  
pp. 81-91 ◽  
Author(s):  
H. R. Middleton ◽  
N. J. Mitchell ◽  
H. G. Muller
Keyword(s):  
General Circulation ◽  
Lower Thermosphere ◽  
Correlation Coefficients ◽  
Atmospheric Dynamics ◽  
Meridional Component ◽  
Zonal Winds ◽  
Meridional Winds ◽  
Middle Atmospheric Dynamics ◽  
The Uk ◽  
Mlt Region

Abstract. A meteor radar in the UK (near 52° N) has been used to measure the mean winds of the mesosphere/lower-thermosphere (MLT) region over the period 1988–2000. The seasonal course and interannual variability is characterised and comparisons are made with a number of models. Annual mean wind trends were found to be + 0.37 ms-1 yr-1 for the zonal component and + 0.157 ms-1 yr-1 for the meridional component. Seasonal means revealed significant trends in the case of meridional winds in spring ( + 0.38 ms-1 yr-1) and autumn ( + 0.29 ms-1 yr-1), and zonal winds in summer ( + 0.48 ms-1 yr-1) and autumn ( + 0.38 ms-1 yr-1). Significant correlation coefficients, R, between the sunspot number and seasonal mean wind are found in four instances. In the case of the summer zonal winds, R = + 0.732; for the winter meridional winds, R = - 0.677; for the winter zonal winds, R = - 0.472; and for the autumn zonal winds R = + 0.508.Key words. Meteorology and atmospheric dynamics (climatology; general circulation; middle atmospheric dynamics)

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