Disrupted Stratospheric QBO signatures in the Diurnal Tides over the low‐latitude MLT region

2021 ◽  
Author(s):  
M. Pramitha ◽  
K. Kishore Kumar ◽  
M. Venkat Ratnam ◽  
M. Praveen ◽  
S. Vijaya Bhaskara Rao
Keyword(s):  
Low Latitude ◽  
Mlt Region ◽  
Diurnal Tides

Experimental evidence for solar cycle and long-term change in the low-latitude MLT region

2005 ◽  
Vol 67 (1-2) ◽  
pp. 191-196 ◽  
Author(s):  
Barclay Clemesha ◽  
Hisao Takahashi ◽  
Dale Simonich ◽  
Delano Gobbi ◽  
Paulo Batista
Keyword(s):  
Solar Cycle ◽  
Experimental Evidence ◽  
Low Latitude ◽  
Term Change ◽  
Mlt Region

scholarly journals Vertical propagation characteristics and seasonal variability of tidal wind oscillations in the MLT region over Trivandrum (8.5° N, 77° E): first results from SKiYMET Meteor Radar

2006 ◽  
Vol 24 (11) ◽  
pp. 2877-2889 ◽  
Author(s):  
V. Deepa ◽  
G. Ramkumar ◽  
M. Antonita ◽  
K. K. Kumar ◽  
M. N. Sasi
Keyword(s):  
Seasonal Variation ◽  
Seasonal Variability ◽  
Phase Structure ◽  
Atmospheric Tides ◽  
Meteor Radar ◽  
Propagation Characteristics ◽  
Vertical Wavelength ◽  
Vertical Propagation ◽  
Mlt Region ◽  
Diurnal Tides

Abstract. Tidal activity in the Mesospheric Lower Thermosphere (MLT) region over Trivandrum (8.5° N, 77° E) is investigated using the observations from newly installed SKiYMET Meteor Radar. The seasonal variability and vertical propagation characteristics of atmospheric tides in the MLT region are addressed in the present communication. The observations revealed that the diurnal tide is more prominent than the semi/terdiurnal components over this latitude. It is also observed that the amplitudes of meridional components are stronger than that of zonal ones. The amplitude and phase structure shows the vertical propagation of diurnal tides with vertical wavelength of ~25 km. However, the vertical wavelength of the semidiurnal tide showed considerable variations. The vertical propagation characteristics of the terdiurnal tide showed some indications of their generating mechanisms. The observed features of tidal components are compared with Global Scale Wave Model (GSWM02) values and they showed a similar amplitude and phase structure for diurnal tides. Month-to-month variations in the tidal amplitudes have shown significant seasonal variation. The observed seasonal variation is discussed in light of the variation in tidal forcing and dissipation.

scholarly journals First results from the CAWSES-India Tidal Campaign

2008 ◽  
Vol 26 (8) ◽  
pp. 2323-2331 ◽  
Author(s):  
S. Gurubaran ◽  
D. Narayana Rao ◽  
G. Ramkumar ◽  
T. K. Ramkumar ◽  
G. Dutta ◽  
...  
Keyword(s):  
Lower Thermosphere ◽  
Weather Data ◽  
Atmospheric Tides ◽  
Data Sets ◽  
Low Latitude ◽  
First Results ◽  
Mesosphere And Lower Thermosphere ◽  
Nonmigrating Tides ◽  
The Western Pacific ◽  
Mlt Region

Abstract. The first CAWSES-India Tidal Campaign was conducted by the Indian scientific community during March–April 2006. The objectives of this campaign were: (1) To determine the characteristics of tides in the troposphere and lower stratosphere (0–20 km) and mesosphere and lower thermosphere (MLT) region (80–100 km), (2) to explore and identify what lower atmospheric processes drive middle atmospheric tides in the Indian continental region and (3) to provide information on those short-term variabilities of MLT tides that are likely to have an impact on the ionospheric variabilities and contribute to the upper atmospheric weather. Data sets from experiments conducted at the three low latitude radar sites, namely, Trivandrum (8.5° N, 76.9° E), Tirunelveli (8.7° N, 77.8° E) and Gadanki (13.5° N, 79.2° E) and fortnightly rocket launches from Thumba were made use of in this study. An important observational finding reported in this work is that the radar observations at Tirunelveli/Trivandrum indicate the presence of 15–20 day modulation of diurnal tide activity at MLT heights during the February–March period. A similar variation in the OLR fields in the western Pacific (120–160° longitude region) suggests a possible link between the observed tidal variabilities and the variations in the deep tropical convection through the nonmigrating tides it generates.

scholarly journals Variability of MLT winds and waves over mid-latitude during the 2000/2001 and 2009/2010 winter stratospheric sudden warming

2012 ◽  
Vol 30 (6) ◽  
pp. 991-1001 ◽  
Author(s):  
X. Chen ◽  
X. Hu ◽  
C. Xiao
Keyword(s):  
Gravity Waves ◽  
Zonal Wind ◽  
Lower Thermosphere ◽  
Temporal Variations ◽  
Low Latitude ◽  
Stratospheric Sudden Warming ◽  
Stratospheric Temperature ◽  
Wind Structure ◽  
Polar Stratosphere ◽  
Mlt Region

Abstract. The mesosphere and lower thermosphere (MLT) wind structure over Wuhan (30° N, 114° E) in 2000/2001 winter and over Langfang (39.4° N, 116.6° E) in 2009/2010 winter are examined to reveal the effects of stratospheric sudden warming (SSW) in mid-low-latitude MLT region. The result shows that the MLT daily zonal wind over these two sites reversed from eastward wind to westward wind for several days during the SSW events. The reversals were almost coincident with the polar stratospheric temperature reaching its maximum at 10 hPa, 90° N and were about ten days prior to the reversal of high latitude stratospheric zonal wind at 10 hPa, 60° N. The temporal variations of tides, gravity waves and 2-day planetary waves in the mid-latitude MLT showed different behavior during the two SSW events. During the 2001 SSW event, MLT diurnal tide reached its maximum when the MLT zonal wind decreased rapidly and SSW event began in polar stratosphere; the activity of 2-day waves decreased after the onset of the 2001 SSW, while the gravity wave increased when the 2001 SSW developed into a major warming. However, in the 2009/2010 winter, the semidiurnal tide and 2-day wave in MLT over Langfang reached a peak about two days earlier than zonal wind reversal at 10 hPa, 60° N; no significant features were found in diurnal tides, terdiurnal tides and gravity waves related to the 2010 SSW event.

Progress report on 21-cm observations at low latitude between longitudes (l 11) 0° and 66°

1967 ◽  
Vol 31 ◽  
pp. 177-179
Author(s):  
W. W. Shane
Keyword(s):  
Preliminary Report ◽  
Progress Report ◽  
Galactic Centre ◽  
Low Latitude ◽  
The Third ◽  
Introductory Lecture ◽  
Centre Region

In the course of several 21-cm observing programmes being carried out by the Leiden Observatory with the 25-meter telescope at Dwingeloo, a fairly complete, though inhomogeneous, survey of the regionl11= 0° to 66° at low galactic latitudes is becoming available. The essential data on this survey are presented in Table 1. Oort (1967) has given a preliminary report on the first and third investigations. The third is discussed briefly by Kerr in his introductory lecture on the galactic centre region (Paper 42). Burton (1966) has published provisional results of the fifth investigation, and I have discussed the sixth in Paper 19. All of the observations listed in the table have been completed, but we plan to extend investigation 3 to a much finer grid of positions.

Low‐Latitude Whistler‐Mode and Higher‐Latitude Z‐mode Emission at Jupiter Observed by Juno

2020 ◽  
Author(s):  
J. D. Menietti ◽  
T. F. Averkamp ◽  
M. Imai ◽  
W. S. Kurth ◽  
G. B. Clark ◽  
...  
Keyword(s):  
Low Latitude ◽  
Whistler Mode
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