Advanced meteor radar installed at Tirupati: System details and comparison with different radars

Abstract

An advanced meteor radar, viz, Sri Venkateswara University (SVU) meteor radar (SVU MR) operating at 35.25 MHz, was installed at Sri Venkateswara University (SVU), Tirupati (13.63°N, 79.4°E), India, in August 2013 for continuous observations of horizontal winds in the mesosphere and lower thermosphere (MLT). This manuscript describes the purpose of the meteor radar, system configuration, measurement techniques, its data products, and operating parameters, as well as a comparison of measured mean winds in the MLT with contemporary radars over the Indian region. It is installed close to the Gadanki (13.5°N, 79.2°E) mesosphere-stratosphere-troposphere (MST) radar to fill the region between 85 and 100 km where this radar does not measure winds. The present radar provides additional information due to its high meteor detection rate, which results in accurate wind information from 70 to 110 km. As a first step, we made a comparison of SVU MR-derived horizontal winds in the MLT region with those measured by similar and different (MST and MF radars) techniques over the Indian region, as well as model (horizontal wind model 2007) data sets. The comparison showed an exquisite agreement between the overlapping altitudes (82-98 km) of different radars. Zonal winds compared very well, as did the meridional winds. The observed discrepancies and limitations in the wind measurement are discussed in the light of different measuring techniques and the effects of small-scale processes like gravity waves. This new radar is expected to play an important role in our understanding of the vertical and lateral coupling of different regions of the atmosphere that will be possible when measurements from nearby locations are combined.

Mesospheric signatures observed during 2010 minor stratospheric warming at King Sejong Station (62°S, 59°W)

“…The background wind contains both gravity waves and tides. It is clear from the figures that both zonal and meridional winds at these two locations show strong similarities, except that the Rothera winds are weaker than those from KSS MR at higher altitudes as expected (Rao et al, 2014). Since, the two radars are separated only by 8 o latitude, significant difference in winds is not expected (Dowdy et al, 2004), which is confirmed in these figures.…”

“…The radar operates with a transmitting power of 25 kW at a frequency of 1.98 MHz (Hibbins et al, 2007) and provides winds in the mesosphere and lower thermosphere at 4 km altitude resolution every hour and these data were re-sampled to 2 km height resolution. The winds measured by a MF radar are usually in agreement with those measured by a meteor radar up to an altitude of ~94 km, above which a MF radar tends to underestimate the winds compared to those observed by a meteor radar (Manson et al, 2004;Portnyagin et al, 2004;Rao et al, 2014). In the present study we made use of winds at 82 km to characterize the mesosphere response to the 2010 minor SSW.…”

“…The difference in wind magnitude can be attributed partly to the difference in wind measuring techniques. Usually MF radars tend to underestimate the winds than meteor radars (Rao et al, 2014). In the case of SD-WACCM the wind weakening at 82 km started along with radar observations of wind reversal, and became negative just a few days before the associated warming in the stratosphere.…”

Wuhan MST radar: Technical features and Validation of wind observations

“…8(b), the data acquisition rate of the high mode is mainly concentrated at heights of 66-86 km with a maximum up to 17%, which is lower than that of the low and middle mod. It is because the winds in the mesosphere are only available during the daytime (8 LT-16 LT) in the D region (due to insufficient D region ionization during nighttime) (Rao et al, 2014). Actually, if the time range is limited in the daytime, the maximum data acquisition of the high mode is more than 50%.…”

“…Two reasons might be resulting in the discrepancies between the observations of the two radars. The first one is the localized gravity waves, tides or planetary waves could make the differences between them (Rao et al, 2014;Ratnam et al, 2001). The second is that the low data acquisition rate of the Wuhan MST radar in the mesosphere could lead to the fluctuations of the daily mean data, which shows the sudden changes of the MST radar measurements at some heights.…”