Comparison Of Wind Measurements Research Articles

Comparison of wind measurements by means of industrially produced sodar and high-altitude meteorological mast in Obninsk

The real characteristics of the MFAS sodar industrially produced by Scintec AG (Germany) are given. The paper presents a wider range of altitudes as compared with the papers published before as a result of using the meteorological mast with the height of 310 m and longer duration of practically continuous testing embracing different weather conditions in the period from July to November 2008. During the comparison, the 10-min averaging time for the wind speed and direction is used. The comparison of the data of acoustic sounding and contact measurement methods indicates that the sodar provides reliable information on the vertical profiles of average wind speed within the considered altitude range up to 300 m except the cases of heavy rainfalls and low wind speed.

Comment on “Initial results from SKiYMET meteor radar at Thumba (8.5°N, 77°E): 1. Comparison of wind measurements with MF spaced antenna radar system” by Karanam Kishore Kumar et al.

Comment on “Initial results from SKiYMET meteor radar at Thumba (8.5°N, 77°E): 1. Comparison of wind measurements with MF spaced antenna radar system” by Karanam Kishore Kumar et al.

Reply to comment by R. Dhanya and S. Gurubaran on “Initial results from SKiYMET meteor radar at Thumba (8.5°N, 77°E): 1. Comparison of wind measurements with MF spaced antenna radar system”

Reply to comment by R. Dhanya and S. Gurubaran on “Initial results from SKiYMET meteor radar at Thumba (8.5°N, 77°E): 1. Comparison of wind measurements with MF spaced antenna radar system”

Comparison of wind measurements in the troposphere and mesosphere by VHF/MF radars and in-situ techniques

Abstract. Radar wind observations at frequencies between 1.98 and 53.5 MHz obtained at polar latitudes were compared to in-situ wind measurements by radiosondes at tropospheric altitudes and to winds from falling spheres at mesospheric altitudes. Comparisons are shown for several campaigns of radiosonde and falling sphere observations. The radar wind directions agree well to the radiosonde and falling sphere observations and are highly correlated. The winds estimated from radar measurements are less than the radiosonde data by about 15% for spaced antenna observations and by about 10% for the Doppler beam swinging experiment. At mesospheric altitudes the spaced antenna winds obtained from the wide-beam Andenes MF radar are underestimated in the order of 35% and winds from the narrow-beam Saura MF radar are underestimated by about 20% compared to falling sphere winds at altitudes between 70 and 80 km. Furthermore, the relation between wind measurements using narrow-beam and wide-beam antenna arrangements for the MF radars is discussed and VHF radar observations are compared to the wide-beam MF radar.

Initial results from SKiYMET meteor radar at Thumba (8.5°N, 77°E): 1. Comparison of wind measurements with MF spaced antenna radar system

In the present communication, initial results from the allSKy interferometric METeor (SKiYMET) radar installed at Thumba (8.5°N, 77°E) are presented. The meteor radar system provides hourly zonal and meridional winds in the mesosphere lower thermosphere (MLT) region. The meteor radar measured zonal and meridional winds are compared with nearby MF radar at Tirunalveli (8.7°N, 77.8°E). The present study provided an opportunity to compare the winds measured by the two different techniques, namely, interferometry and spaced antenna drift methods. Simultaneous wind measurements for a total number of 273 days during September 2004 to May 2005 are compared. The comparison showed a very good agreement between these two techniques in the height region 82–90 km and poor agreement above this height region. In general, the zonal winds compare very well as compared to the meridional winds. The observed discrepancies in the wind comparison above 90 km are discussed in the light of existing limitations of both the radars. The detailed analysis revealed the consistency of the measured winds by both the techniques. However, the discrepancies are observed at higher altitudes and are attributed to the contamination of MF radar neutral wind measurements with Equatorial Electro Jet (EEJ) induced inospheric drifts rather than the limitations of the spaced antenna technique. The comparison of diurnal variation of zonal winds above 90 km measured by both the radars is in reasonably good agreement in the absence of EEJ (during local nighttime). It is also been noted that the difference in the zonal wind measurements by both the radars is directly related to the strength of EEJ, which is a noteworthy result from the present study.

Validation of imaging Doppler interferometer winds using meteor radar

There has been some debate over the years concerning the accuracy of mesospheric wind observations made using the imaging Doppler interferometer (IDI) technique. The high potential and increasing use of IDI wind data in joint studies with spaced‐antenna MF and meteor radar systems make it important to quantify the IDI results. This paper presents a novel comparison of wind measurements between a dynasonde implementation of IDI and winds derived from an all‐sky meteor radar system, a widely‐accepted standard for such measurements. Both radars were located at the USU Bear Lake Observatory and operated almost continuously for a four‐month period. The winds and tides derived from IDI were found to closely match those measured by meteor radar, not only during the day but also at night, and at all overlapping heights from 80–95 km.

Comparison of wind measurements between Yamagawa MF Radar and the MU Radar

A new MF radar was installed at Yamagawa (31.20°N, 130.62°E), Japan in August, 1994 by the Communications Research Laboratory, and the first comparison of wind measurements taken with the Yamagawa MF radar and meteor wind measurements with the MU radar at Shigaraki (34.85°N, 136.10°E) are carried out. In spite of their spatial separation of approximately 650 km, reasonable agreement between wind velocities by the two radars at 80–92 km in altitude is confirmed, except for small scale perturbations that are probably due to gravity waves enhanced for the period from 17 h LT on September 13 to 7 h LT on September 14, 1994. It is found that the winds of the MF radar above 92 km tend to be smaller than the winds obtained with the MU radar. Receiver saturation and interference are possible causes of the reduced wind velocities observed with the MF radar. The height structures of semidiurnal tides are also compared. The amplitude and phase of zonal components agree at most heights between the two radars. For the meridional component the amplitudes fluctuate above 88 km with a significant difference and the phase from the MU radar leads that of the MF radar by less than several hours at 86 km to 92 km. An enhanced gravity wave seems to pass over the MU radar almost from north to south, resulting in a contamination of the meridional wind component of the semidiurnal variation.

Comparison of HRDI wind measurements with radar and rocket observations

Wind fields in the mesosphere and lower thermosphere are obtained with the High Resolution Doppler Imager (HRDI) on the Upper Atmosphere Research Satellite (UARS) by observing the Doppler shifts of emission lines in the O2 Atmospheric band. The validity of the measured winds depends on an accurate knowledge of the positions on the detector of the observed lines in the absence of a wind induced Doppler shift. These positions have been determined to an accuracy of approximately 5 ms−1 from the comparison of winds measured by HRDI with those obtained by MF radars. Excellent agreement is found between HRDI measured winds and winds observed with radars and rockets. In addition, the sensitivity of HRDI to migrating tides and other large scale waves is demonstrated.