Correlation between foEs and zonal winds over Rome, Okinawa and Townsville using Horizontal Wind Model (HWM14) during solar cycle 22

2021 ◽  
Author(s):  
Bushra Gul ◽  
Muhammad Ayyaz Ameen ◽  
Tobias G.W. Verhulst
Keyword(s):  
Solar Cycle ◽  
Horizontal Wind ◽  
Wind Model ◽  
Zonal Winds

scholarly journals A Comparison of Meteor Radar Observation over China Region with Horizontal Wind Model (HWM14)

Atmosphere ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 98
Author(s):  
Qiong Tang ◽  
Yufeng Zhou ◽  
Zhitao Du ◽  
Chen Zhou ◽  
Jiandong Qiao ◽  
...  
Keyword(s):  
Model Prediction ◽  
Meridional Wind ◽  
Radar Observation ◽  
Horizontal Wind ◽  
Meteor Radar ◽  
Wind Fields ◽  
Wind Model ◽  
Zonal Winds ◽  
Radar Measurements ◽  
China Region

This paper compares the wind fields measured by the meteor radar at Mohe, Beijing, Wuhan, and Sanya stations and horizontal wind model (HWM14) predictions. HWM14 appears to successfully reproduce the height-time distribution of the monthly mean zonal winds, although large discrepancies occur in wind speed between the model and measurement, especially in the summer and winter months. For meridional wind, the consistency between model prediction and radar observation is worse than that of zonal wind. The consistency between radar measurements and model prediction at Sanya station is worse than other sites located at higher latitudes. Harmonic analysis reveals large discrepancies in diurnal, semidiurnal, and terdiurnal tides extracted from meteor radar observations and HWM14 predictions.

scholarly journals Climatology of thermospheric neutral winds over Oukaïmeden Observatory in Morocco

2017 ◽  
Vol 35 (1) ◽  
pp. 161-170 ◽  
Author(s):  
Mohamed Kaab ◽  
Zouhair Benkhaldoun ◽  
Daniel J. Fisher ◽  
Brian Harding ◽  
Aziza Bounhir ◽  
...  
Keyword(s):  
Dissociative Recombination ◽  
Horizontal Wind ◽  
Wind Model ◽  
Neutral Winds ◽  
Zonal Winds ◽  
Early Evening ◽  
Atlas Mountains ◽  
Fabry Perot ◽  
Meridional Winds ◽  
High Atlas Mountains

Abstract. In order to explore coupling between the thermosphere and ionosphere and to address the lack of data relating to thermospheric neutral winds and temperatures over the African sector, a new system of instruments was installed at the Oukaïmeden Observatory located in the high Atlas Mountains, 75 km south of Marrakesh, Morocco (31.206° N, 7.866° W, 22.84° N magnetic). In this work we present the first multi-year results of the climatology of meridional and zonal winds obtained during the period from January 2014 to February 2016, including observations from 648 nights. The measurements are obtained using an imaging Fabry–Pérot interferometer, which measures the 630.0 nm emissions caused by dissociative recombination of O2+. The basic climatology of the winds is as expected, showing zonal winds that are strongly eastward in the early evening just after sunset with a speed of 50 to 100 m s−1 decreasing in magnitude, and reversing directions in the local summer months, towards sunrise. The meridional winds are slightly poleward in the early evening during the local winter, before reversing directions around 21:00 LT. In the local summer months, the meridional winds are equatorward for the entire night, reaching a maximum equatorward speed of 75 m s−1. We compare the observed climatologies of neutral winds to that provided by the recently updated Horizontal Wind Model (HWM14) in order to validate that model's predictions of the thermospheric wind patterns over the eastern portion of Africa. The model captures much of the features in the observational climatologies. The most notable exception is for the zonal winds during local summer, when the maximum eastward wind in the observations occurs approximately 4 h later than seen in the model results.

scholarly journals Comparison of high-latitude thermospheric meridionalwinds I: optical and radar experimental comparisons

2004 ◽  
Vol 22 (3) ◽  
pp. 849-862 ◽  
Author(s):  
E. M. Griffin ◽  
I. C. F. Müller-Wodarg ◽  
A. Aruliah ◽  
A. Aylward
Keyword(s):  
Solar Cycle ◽  
High Latitude ◽  
Model Performance ◽  
Meridional Wind ◽  
Experimental Techniques ◽  
Horizontal Wind ◽  
Wind Model ◽  
Data Set ◽  
Neutral Winds ◽  
Eiscat Measurements

Abstract. Thermospheric neutral winds at Kiruna, Sweden (67.4°N, 20.4°E) are compared using both direct optical Fabry-Perot Interferometer (FPI) measurements and those derived from European incoherent scatter radar (EISCAT) measurements. This combination of experimental data sets, both covering well over a solar cycle of data, allows for a unique comparison of the thermospheric meridional component of the neutral wind as observed by different experimental techniques. Uniquely in this study the EISCAT measurements are used to provide winds for comparison using two separate techniques: the most popular method based on the work of Salah and Holt (1974) and the Meridional Wind Model (MWM) (Miller et al., 1997) application of servo theory. The balance of forces at this location that produces the observed diurnal pattern are investigated using output from the Coupled Thermosphere and Ionosphere (CTIM) numerical model. Along with detailed comparisons from short periods the climatological behaviour of the winds have been investigated for seasonal and solar cycle dependence using the experimental techniques. While there are features which are consistent between the 3 techniques, such as the evidence of the equinoctial asymmetry, there are also significant differences between the techniques both in terms of trends and absolute values. It is clear from this and previous studies that the high-latitude representation of the thermospheric neutral winds from the empirical Horizontal Wind Model (HWM), though improved from earlier versions, lacks accuracy in many conditions. The relative merits of each technique are discussed and while none of the techniques provides the perfect data set to address model performance at high-latitude, one or more needs to be included in future HWM reformulations. Key words. Meteorology and atmospheric dynamics (thermospheric dynamics), Ionosphere (ionosphere-atmosphere interactions, auroral ionosphere)

Horizontal wind model (HWM) (1990)

1992 ◽  
Vol 40 (4) ◽  
pp. 556-557 ◽  
Author(s):  
A.E. Hedin
Keyword(s):  
Horizontal Wind ◽  
Wind Model

scholarly journals Characteristics of Stratospheric Winds over Jiuquan (41.1°N, 100.2°E) Using Rocketsonde Data in 1967–2004

2017 ◽  
Vol 34 (3) ◽  
pp. 657-667 ◽  
Author(s):  
Z. Sheng ◽  
J. W. Li ◽  
Y. Jiang ◽  
S. D. Zhou ◽  
W. L. Shi
Keyword(s):  
Zonal Wind ◽  
Middle Atmosphere ◽  
Correlation Coefficients ◽  
Meridional Wind ◽  
Horizontal Wind ◽  
Cycle Period ◽  
Observation Data ◽  
Wind Fields ◽  
Zonal Winds ◽  
Model Research

AbstractStratospheric winds play a significant role in middle atmosphere dynamics, model research, and carrier rocket experiments. For the first time, 65 sets of rocket sounding experiments conducted at Jiuquan (41.1°N, 100.2°E), China, from 1967 to 2004 are presented to study horizontal wind fields in the stratosphere. At a fixed height, wind speed obeys the lognormal distribution. Seasonal mean winds are westerly in winter and easterly in summer. In spring and autumn, zonal wind directions change from the upper to the lower stratosphere. The monthly zonal mean winds have an annual cycle period with large amplitudes at high altitudes. The correlation coefficients for zonal winds between observations and the Horizontal Wind Model (HWM) with all datasets are 0.7. The MERRA reanalysis is in good agreement with rocketsonde data according to the zonal winds comparison with a coefficient of 0.98. The sudden stratospheric warming is an important contribution to biases in the HWM, because it changes the zonal wind direction in the midlatitudes. Both the model and the reanalysis show dramatic meridional wind differences with the observation data.

scholarly journals Monitoring observations of meteor echo at the EKB ISTP SB RAS radar: algorithms, validation, statistics

2021 ◽  
Vol 7 (1) ◽  
pp. 47-58
Author(s):  
Roman Fedorov ◽  
Oleg Berngardt
Keyword(s):  
Least Squares Method ◽  
Weighted Least Squares ◽  
Three Dimensional ◽  
Radar Data ◽  
Meteor Shower ◽  
Horizontal Wind ◽  
Doppler Velocity ◽  
Wind Model ◽  
Weighted Least Squares Method ◽  
Meteor Trails

The paper considers the implementation of algorithms for automatic search for signals scattered by meteor trails according to EKB ISTP SB RAS radar data. In general, the algorithm is similar to the algorithms adopted in specialized meteor systems. The algorithm is divided into two stages: detecting a meteor echo and determining its parameters. We show that on the day of the maximum Geminid shower, December 13, 2016, the scattered signals detected by the algorithm are foreshortening and correspond to scattering by irregularities extended in the direction of the meteor shower radiant. This confirms that the source of the signals detected by the algorithm is meteor trails. We implement an additional program for indirect trail height determination. It uses a decay time of echo and the NRLMSIS-00 atmosphere model to estimate the trail height. The dataset from 2017 to 2019 is used for further testing of the algorithm. We demonstrate a correlation in calculated Doppler velocity between the new algorithm and FitACF. We present a solution of the inverse problem of reconstructing the neutral wind velocity vector from the data obtained by the weighted least squares method. We compare calculated speeds and directions of horizontal neutral winds, obtained in the three-dimensional wind model, and the HWM-14 horizontal wind model. The algorithm allows real-time scattered signal processing and has been put into continuous operation at the EKB ISTP SB RAS radar.

scholarly journals Thermospheric winds and temperatures above Mawson, Antarctica, observed with an all-sky imaging, Fabry-Perot spectrometer

2009 ◽  
Vol 27 (5) ◽  
pp. 2225-2235 ◽  
Author(s):  
C. Anderson ◽  
M. Conde ◽  
P. Dyson ◽  
T. Davies ◽  
M. J. Kosch
Keyword(s):  
Large Scale ◽  
Atmospheric Model ◽  
Horizontal Wind ◽  
Data Set ◽  
Average Behavior ◽  
Wind Speeds ◽  
Zonal Winds ◽  
F Region ◽  
Fabry Perot ◽  
Thermospheric Winds

Abstract. A new all-sky imaging Fabry-Perot spectrometer has been installed at Mawson station (67°36' S, 62°52' E), Antarctica. This instrument is capable of recording independent spectra from many tens of locations across the sky simultaneously. Useful operation began in March 2007, with spectra recorded on a total of 186 nights. Initial analysis has focused on the large-scale daily and average behavior of winds and temperatures derived from observations of the 630.0 nm airglow line of atomic oxygen, originating from a broad layer centered around 240 km altitude, in the ionospheric F-region. The 1993 Horizontal Wind Model (HWM93), NRLMSISE-00 atmospheric model, and the Coupled Thermosphere/Ionosphere Plasmasphere (CTIP) model were used for comparison. During the geomagnetically quiet period studied, observed winds and temperatures were generally well modelled, although temperatures were consistently higher than NRLMSISE-00 predicted, by up to 100 K. CTIP temperatures better matched our data, particularly later in the night, but predicted zonal winds which were offset from those observed by 70–180 ms−1 westward. During periods of increased activity both winds and temperatures showed much greater variability over time-scales of less than an hour. For the active night presented here, a period of 45 min saw wind speeds decrease by around 180 ms−1, and temperatures increase by approximately 100 K. Active-period winds were poorly modelled by HWM93 and CTIP, although observed median temperatures were in better agreement with NRLMSISE-00 during such periods. Average behavior was found to be generally consistent with previous studies of thermospheric winds above Mawson. The collected data set was representative of quiet geomagnetic and solar conditions. Geographic eastward winds in the afternoon/evening generally continued until around local midnight, when winds turned equatorward. Geographic meridional and zonal winds in the afternoon were approximately 50 ms−1 weaker than expected from HWM93, as was the transition to equatorward flow around midnight. There was also a negligible geographic zonal component to the post-midnight wind where HWM93 predicted strong westward flow. Average temperatures between 19:00 and 04:00 local solar time were around 60 K higher than predicted by NRLMSISE-00.

scholarly journals Winds and tides in the mid-latitude Southern Hemisphere upper mesosphere recorded with the Falkland Islands SuperDARN radar

2011 ◽  
Vol 29 (11) ◽  
pp. 1985-1996 ◽  
Author(s):  
R. E. Hibbins ◽  
M. P. Freeman ◽  
S. E. Milan ◽  
J. M. Ruohoniemi
Keyword(s):  
Southern Hemisphere ◽  
Wind Data ◽  
Atmospheric Tides ◽  
Horizontal Wind ◽  
Falkland Islands ◽  
First Year ◽  
Wind Model ◽  
The North ◽  
Winter Time ◽  
Good Agreement

Abstract. Meteor wind data from the first year of operation of the Falkland Islands SuperDARN radar (52° S, 59° W) are used to characterize the atmospheric tides and background winds in the upper mesosphere above the South Atlantic. Strong (>40 m s−1) semidiurnal tides are observed in the winter time and large amplitude (>60 m s−1) bursts of quasi two-day wave activity are seen in January 2011. Data are in good agreement with those presented from the SAAMER meteor radar (54° S, 68° W). Comparison with SuperDARN meteor wind data from a geographically similar Northern Hemisphere site at Goose Bay (53° N 60° W) reveal clear interhemispheric differences especially in the semidiurnal and terdiurnal components of the tides. The winter time amplitudes of the tides are much stronger in the Southern Hemisphere than in the north. Background winds are observed to be significantly more polewards and westwards throughout the year than those predicted by the empirical horizontal wind model HWM07.

scholarly journals On the solar cycle dependence of winds and planetary waves as seen from mid-latitude D1 LF mesopause region wind measurements

1998 ◽  
Vol 16 (12) ◽  
pp. 1534-1543 ◽  
Author(s):  
C. Jacobi
Keyword(s):  
Regression Analysis ◽  
Solar Activity ◽  
Solar Cycle ◽  
Multiple Regression Analysis ◽  
Multiple Regression ◽  
Middle Atmosphere ◽  
Horizontal Wind ◽  
Prevailing Wind ◽  
Mean Values ◽  
Wind Measurements

Abstract. At the Collm Observatory of the University of Leipzig LF D1 low-frequency total reflection night-time wind measurements have been carried out continuously for more than two decades. Using a multiple regression analysis to derive prevailing winds, tides and the quasi-2-day wave from the half-hourly mean values of the horizontal wind components, monthly mean values of mesopause wind parameters are obtained that can be analysed with respect to long-term trends and influences of solar variability. The response of the prevailing wind to the 11-year solar cycle differs throughout the year. While in winter no significant correlation between the zonal prevailing wind and solar activity is found, in spring and summer a negative correlation between the TWC can be seen from the measurements. This is connected with stronger vertical gradients of the zonal prevailing wind during solar maximum than during solar minimum. Since the amplitude of the quasi-2-day wave is dependent on the zonal mean wind vertical gradient, this is connected with a positive correlation between solar activity and quasi-two-day wave activity.Key words. Meteorology and atmospheric dynamics · Middle atmosphere dynamics Multiple regression analysis Quasi-2-day wave

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