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 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 Observations of equatorial mesospheric winds over Cariri (7.4° S) by a meteor radar and comparison with existing models

2008 ◽  
Vol 26 (3) ◽  
pp. 485-497 ◽  
Author(s):  
R. A. Buriti ◽  
W. K. Hocking ◽  
P. P. Batista ◽  
A. F. Medeiros ◽  
B. R. Clemesha
Keyword(s):  
Annual Variation ◽  
Meridional Wind ◽  
The Other ◽  
Horizontal Wind ◽  
Meteor Radar ◽  
Wind Model ◽  
International Reference ◽  
Reference Atmosphere ◽  
One Year ◽  
Semiannual Oscillation

Abstract. Mesospheric winds observed with a meteor radar at Cariri (7.4° S, 36.5° W), Brazil, during the period of July 2004 to June 2005, show a clear semiannual oscillation known as the Mesospheric Semiannual Oscillation (MSAO), which maximizes in the zonal mean wind mainly at 82 km, with amplitude decreasing with height. Maximum westward winds for the MSAO occurred in March and September. The meridional wind, on the other hand, presented a clear annual variation maximizing in December. On average, the amplitude of the meridional MSAO was smaller than the zonal MSAO component. Comparison with models shows on occasions that there are significant differences between the observed winds and the CIRA (Cospar International Reference Atmosphere) and HWM93 (Horizontal Wind Model) models. In addition, diurnal and semidiurnal parameters were calculated and compared to the GSWM model. Other results observed during one year of data are presented in this work.

First studies of mesospheric momentum flux and wind fields using the SIMONe system over Patagonia

2020 ◽  
Author(s):  
Fede Conte ◽  
Jorge Chau ◽  
Brian Harding ◽  
Ralph Latteck ◽  
Jacobo Salvador
Keyword(s):  
Gravity Wave ◽  
Spread Spectrum ◽  
Momentum Flux ◽  
Active Regions ◽  
Meridional Wind ◽  
Wave Activity ◽  
Flux Analysis ◽  
Meteor Radar ◽  
Wind Fields ◽  
Southern Patagonia

<p>During September of 2019, a state-of-the-art multistatic meteor radar system called SIMONe (Spread Spectrum Interferometric Multistatic meteor radar Observing Network) was installed in southern Patagonia, Argentina. Its main goal being the study of mesospheric waves in one of the (theoretically predicted) most dynamically active regions of the world. SIMONe Patagonia consists of 5 linearly polarized Yagi antennas in a pentagon configuration on transmission, and 5 dual-polarization single Yagi antennas on reception, situated between 30 and 270 km from the transmitters, which locate at 49.6° S. Combining measurements from the 5 links allows for more accurate estimations of mean winds and horizontal momentum flux for altitudes between 75 and 105 km. Furthermore, given the significantly higher amount of meteor detections, one can determine wind fields within the limits of the illuminated volume every 1 hour and 1 km in time and height, respectively. Preliminary results indicate a dominant semidiurnal oscillation in both the zonal and meridional wind components, as well as an enhanced and sustained (in time) gravity wave activity, especially above 90 km of altitude. In addition, momentum flux analysis reveals that the gravity wave activity is stronger than in other parts of the Southern Hemisphere, confirming that Patagonia is indeed a very active region at mesospheric heights.  </p>

Validation of multi-static meteor radar analysis using realistic mesospheric dynamics from UA-ICON model: Reliability of gradients and vertical velocities

2021 ◽  
Author(s):  
Harikrishnan Charuvil Asokan ◽  
Jorge Luis Chau ◽  
Juan Federico Conte ◽  
Gerd Baumgarten ◽  
Juha Vierinen ◽  
...  
Keyword(s):  
Spread Spectrum ◽  
General Circulation ◽  
Lower Thermosphere ◽  
Circulation Model ◽  
Horizontal Wind ◽  
Meteor Radar ◽  
Wind Fields ◽  
Network Systems ◽  
Mlt Dynamics ◽  
Static Approach

<p>Specular meteor radars (SMRs) are a major ground-based instrument to study the mesosphere and the lower thermosphere (MLT) dynamics. The recently developed multi-static approach of SMRs allows maximising the number of measurements from different viewing angles, hence enabling the estimation of horizontal wind fields and their second-order statistics (power spectrum, momentum fluxes). We have installed the operational versions of these techniques in Germany, Peru and Argentina, called SIMONe (Spread-spectrum Interferometric Multistatic meteor radar Observing Network) systems. Here, we present a validation study of multi-static meteor radar analysis by using virtual radar systems on the upper-atmosphere extension of the ICOsahedral Non-hydrostatic (UA-ICON) general circulation model with a horizontal grid spacing of 5 km. This particular study is focusing on the estimates of gradients and vertical velocities with these multi-static systems.</p>

scholarly journals FPI observations of nighttime mesospheric and thermospheric winds in China and their comparisons with HWM07

2013 ◽  
Vol 31 (8) ◽  
pp. 1365-1378 ◽  
Author(s):  
W. Yuan ◽  
X. Liu ◽  
J. Xu ◽  
Q. Zhou ◽  
G. Jiang ◽  
...  
Keyword(s):  
Zonal Wind ◽  
Annual Variation ◽  
Middle Atmosphere ◽  
Geomagnetic Latitude ◽  
Meridional Wind ◽  
Central China ◽  
Horizontal Wind ◽  
Zonal Winds ◽  
Meridional Winds ◽  
First Time

Abstract. We analyzed the nighttime horizontal neutral winds in the middle atmosphere (~ 87 and ~ 98 km) and thermosphere (~ 250 km) derived from a Fabry–Perot interferometer (FPI), which was installed at Xinglong station (40.2° N, 117.4° E) in central China. The wind data covered the period from April 2010 to July 2012. We studied the annual, semiannual and terannual variations of the midnight winds at ~ 87 km, ~ 98 km and ~ 250 km for the first time and compared them with Horizontal Wind Model 2007 (HWM07). Our results show the following: (1) at ~ 87 km, both the observed and model zonal winds have similar phases in the annual and semiannual variations. However, the HWM07 amplitudes are much larger. (2) At ~ 98 km, the model shows strong eastward wind in the summer solstice, resulting in a large annual variation, while the observed strongest component is semiannual. The observation and model midnight meridional winds agree well. Both are equatorward throughout the year and have small amplitudes in the annual and semiannual variations. (3) There are large discrepancies between the observed and HWM07 winds at ~ 250 km. This discrepancy is largely due to the strong semiannual zonal wind in the model and the phase difference in the annual variation of the meridional wind. The FPI annual variation coincides with the results from Arecibo, which has similar geomagnetic latitude as Xinglong station. In General, the consistency of FPI winds with model winds is better at ~ 87 and ~ 98 km than that at ~ 250 km. We also studied the seasonally and monthly averaged nighttime winds. The most salient features include the following: (1) the seasonally averaged zonal winds at ~ 87 and ~ 98 km typically have small variations throughout the night. (2) The model zonal and meridional nighttime wind variations are typically much larger than those of observations at ~ 87 km and ~ 98 km. (3) At ~ 250 km, model zonal wind compares well with the observation in the winter. For spring and autumn, the model wind is more eastward before ~ 03:00 LT but more westward after. The observed nighttime zonal and meridional winds on average are close to zero in the summer and autumn, which indicates a lack of strong stable tides. The consistency of FPI zonal wind with model wind at ~ 250 km is better than the meridional wind.

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 Mesospheric winds measured by medium-frequency radar with full correlation analysis: error properties and impacts on studies of wind variance

2020 ◽  
Vol 9 (1) ◽  
pp. 223-238
Author(s):  
Maude Gibbins ◽  
Andrew J. Kavanagh
Keyword(s):  
Correlation Analysis ◽  
Gravity Waves ◽  
Horizontal Wind ◽  
Wind Fields ◽  
Medium Frequency ◽  
Wind Retrieval ◽  
Zonal Winds ◽  
Analysis Error ◽  
Full Correlation Analysis

Abstract. The mesosphere is one of the most difficult parts of the atmosphere to sample; it is too high for balloon measurements and too low for in situ satellites. Consequently, there is a reliance on remote sensing (either from the ground or from space) to diagnose this region. Ground-based radars have been used since the second half of the 20th century to probe the dynamics of the mesosphere; medium-frequency (MF) radars provide estimates of the horizontal wind fields and are still used to analyse tidal structures and planetary waves that modulate the meridional and zonal winds. The variance of the winds has traditionally been linked qualitatively to the occurrence of gravity waves. In this paper, the method of wind retrieval (full correlation analysis) employed by MF radars is considered with reference to two systems in Antarctica at different latitude (Halley at 76∘ S and Rothera at 67∘ S). It is shown that the width of the velocity distribution and occurrence of “outliers” is related to the measured levels of anisotropy in the received signal pattern. The magnitude of the error distribution, as represented by the wind variance, varies with both insolation levels and geomagnetic activity. Thus, it is demonstrated that for these two radars the influence of gravity waves may not be the primary mechanism that controls the overall variance.

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)

scholarly journals Retrieving horizontally resolved wind fields using multi-static meteor radar observations

2018 ◽  
Author(s):  
Gunter Stober ◽  
Jorge L. Chau ◽  
Juha Vierinen ◽  
Christoph Jacobi ◽  
Sven Wilhelm
Keyword(s):  
Continuous Wave ◽  
Lower Thermosphere ◽  
Horizontal Wind ◽  
Retrieval Algorithm ◽  
Meteor Radar ◽  
Wind Fields ◽  
Wind Retrieval ◽  
Radar Network ◽  
Frequency Agile ◽  
Kinematic Properties

Abstract. Recently, the MMARIA (Multi-static, multi-frequency Agile Radar for Investigations of the Atmosphere) concept of a multi-static VHF meteor radar network to derive horizontally resolved wind fields in the mesosphere/lower thermosphere was introduced. Here we present preliminary results of the MMARIA network above Eastern Germany using two transmitters located at Juliusruh and Collm, and 5 receiving links two monostatic and three multi-static). The observations are complemented during a one-week campaign, with a couple of addition continuous-wave coded transmitters, making a total of 7 multi-static links. In order to access the kinematic properties of non-homogenous wind fields we developed a wind retrieval algorithm that applies regularization to determine the non-linear wind field in the altitude range of 82–98 km. The derived horizontally resolved wind fields are compared to wind fields retrieved by a more established volume velocity processing that includes the horizontal gradients of the horizontal wind components. The potential of such observations and the new retrieval to investigate gravity waves with horizontal scales between 50–200 km is presented and discussed.

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