Estimation of Mesospheric Densities at Low Latitudes Using the Kunming Meteor Radar Together With SABER Temperatures

2018 ◽  
Vol 123 (4) ◽  
pp. 3183-3195 ◽  
Author(s):  
Wen Yi ◽  
Xianghui Xue ◽  
Iain M. Reid ◽  
Joel P. Younger ◽  
Jinsong Chen ◽  
...  
Keyword(s):  
Meteor Radar ◽  
Low Latitudes

scholarly journals Climatology of the mesopause density using a global distribution of meteor radars

2018 ◽  
Author(s):  
Wen Yi ◽  
Xianghui Xue ◽  
Iain M. Reid ◽  
Damian J. Murphy ◽  
Chris M. Hall ◽  
...  
Keyword(s):  
Northern Hemisphere ◽  
High Latitudes ◽  
Meteor Radar ◽  
Low Latitude ◽  
Wave Forcing ◽  
Spring Equinox ◽  
Spatial Coverage ◽  
Low Latitudes ◽  
Variation Characteristics ◽  
Temporal And Spatial

Abstract. The existing distribution of meteor radars located from high- to low-latitude regions provides a favourable temporal and spatial coverage for investigating the climatology of the global mesopause density. In this study, we report the climatology of the mesopause density estimated using multiyear observations from nine meteor radars, namely, the Davis Station (68.6° S, 77.9° E), Svalbard (78.3° N, 16° E) and Tromsø (69.6° N, 19.2° E) meteor radars located at high latitudes, the Mohe (53.5° N, 122.3° E), Beijing (40.3° N, 116.2° E), Mengcheng (33.4° N, 116.6° E) and Wuhan (30.5° N, 114.6° E) meteor radars located in the mid-latitudes, and the Kunming (25.6° N, 103.8° E) and Darwin (12.3° S, 130.8° E) meteor radars located at low latitudes. The daily mean density was estimated using ambipolar diffusion coefficients derived from the meteor radars and temperatures from the Microwave Limb Sounder (MLS) on board the Aura satellite. The seasonal variations in the Davis Station meteor radar densities in the southern polar mesopause are mainly dominated by an annual oscillation (AO). The mesopause densities observed by the Svalbard and Tromsø meteor radars at high latitudes and the Mohe and Beijing meteor radars at high mid-latitudes in the Northern Hemisphere show mainly an AO and a relatively weak semiannual oscillation (SAO). The mesopause densities observed by the Mengcheng and Wuhan meteor radars at lower mid-latitudes and the Kunming and Darwin meteor radars at low latitudes show mainly an AO. The SAO is evident in the Northern Hemisphere, especially at high latitudes, and its largest amplitude, which is detected at the Tromsø meteor radar, is comparable to the AO amplitudes. These observations indicate that the mesopause densities over the southern and northern high latitudes exhibit a clear seasonal asymmetry. The maxima of the yearly variations in the mesopause densities display a clear temporal variation across the spring equinox as the latitude decreases; these latitudinal variation characteristics may be related to latitudinal changes influenced by gravity wave forcing. In addition to an AO, the mesopause densities over low latitudes also clearly show a variation with a periodicity of 30–60 days related to the Madden-Julian oscillation in the subtropical troposphere.

scholarly journals Estimation of mesopause temperatures at low latitudes using the Kunming meteor radar

Radio Science ◽  
2016 ◽  
Vol 51 (3) ◽  
pp. 130-141 ◽  
Author(s):  
Wen Yi ◽  
Xianghui Xue ◽  
Jinsong Chen ◽  
Xiankang Dou ◽  
Tingdi Chen ◽  
...  
Keyword(s):  
Meteor Radar ◽  
Low Latitudes

scholarly journals Climatology of the mesopause relative density using a global distribution of meteor radars

2019 ◽  
Vol 19 (11) ◽  
pp. 7567-7581 ◽  
Author(s):  
Wen Yi ◽  
Xianghui Xue ◽  
Iain M. Reid ◽  
Damian J. Murphy ◽  
Chris M. Hall ◽  
...  
Keyword(s):  
Relative Density ◽  
Northern Hemisphere ◽  
Latitudinal Variation ◽  
High Latitudes ◽  
Meteor Radar ◽  
Intraseasonal Variation ◽  
Spring Equinox ◽  
Spatial Coverage ◽  
Low Latitudes ◽  
Variation Characteristics

Abstract. The existing distribution of meteor radars located from high- to low-latitude regions provides a favorable temporal and spatial coverage for investigating the climatology of the global mesopause density. In this study, we report the climatology of the mesopause relative density estimated using multiyear observations from nine meteor radars, namely, the Davis Station (68.6∘ S, 77.9∘ E), Svalbard (78.3∘ N, 16∘ E) and Tromsø (69.6∘ N, 19.2∘ E) meteor radars located at high latitudes; the Mohe (53.5∘ N, 122.3∘ E), Beijing (40.3∘ N, 116.2∘ E), Mengcheng (33.4∘ N, 116.6∘ E) and Wuhan (30.5∘ N, 114.6∘ E) meteor radars located in the midlatitudes; and the Kunming (25.6∘ N, 103.8∘ E) and Darwin (12.3∘ S, 130.8∘ E) meteor radars located at low latitudes. The daily mean relative density was estimated using ambipolar diffusion coefficients derived from the meteor radars and temperatures from the Microwave Limb Sounder (MLS) on board the Aura satellite. The seasonal variations in the Davis Station meteor radar relative densities in the southern polar mesopause are mainly dominated by an annual oscillation (AO). The mesopause relative densities observed by the Svalbard and Tromsø meteor radars at high latitudes and the Mohe and Beijing meteor radars at high midlatitudes in the Northern Hemisphere show mainly an AO and a relatively weak semiannual oscillation (SAO). The mesopause relative densities observed by the Mengcheng and Wuhan meteor radars at lower midlatitudes and the Kunming and Darwin meteor radars at low latitudes show mainly an AO. The SAO is evident in the Northern Hemisphere, especially at high latitudes, and its largest amplitude, which is detected at the Tromsø meteor radar, is comparable to the AO amplitudes. These observations indicate that the mesopause relative densities over the southern and northern high latitudes exhibit a clear seasonal asymmetry. The maxima of the yearly variations in the mesopause relative densities display a clear latitudinal variation across the spring equinox as the latitude decreases; these latitudinal variation characteristics may be related to latitudinal changes influenced by gravity wave forcing. In addition to an AO, the mesopause relative densities over low latitudes also clearly show an intraseasonal variation with a periodicity of 30–60 d.

scholarly journals Mesospheric Anomalous Diffusion During Noctilucent Clouds

2018 ◽  
Author(s):  
Fazlul I. Laskar ◽  
Gunter Stober ◽  
Jens Fiedler ◽  
Meers M. Oppenheim ◽  
Jorge L. Chau ◽  
...  
Keyword(s):  
Noctilucent Clouds ◽  
Meteor Radar ◽  
Density Profiles ◽  
Leading Role ◽  
Mesospheric Temperature ◽  
Low Latitudes ◽  
Meteor Trail ◽  
Latitude Effect ◽  
Diffusion Rates ◽  
Thermal Tides

Abstract. The Andenes specular meteor radar shows meteor-trail diffusion rates increasing on average by ~ 20 % at times and locations where a lidar observes noctilucent clouds (NLCs). This high-latitude effect has been attributed to the presence of charged NLC but this study shows that such behaviors result predominantly from thermal tides. To make this claim, the current study evaluates data from three stations, at high-, mid-, and low-latitudes, for the years 2012 to 2016, comparing diffusion to show that thermal tides correlate strongly with the presence of NLCs. This data also shows that the connection between meteor-trail diffusion and thermal tide occurs at all altitudes in the mesosphere, while the NLC influence exists only at high-latitudes and at around peak of NLC layer. This paper discusses a number of possible explanations for changes in the regions with NLCs and leans towards the hypothesis that relative abundance of background electron density plays the leading role. A more accurate model of the meteor trail diffusion around NLC particles would help researchers determine mesospheric temperature and neutral density profiles from meteor radars.

scholarly journals Quasi-90-day oscillation observed in the MLT region at low latitudes from the Kunming meteor radar and SABER

2019 ◽  
Vol 3 (2) ◽  
pp. 1-11 ◽  
Author(s):  
Wen Yi ◽  
◽  
XiangHui Xue ◽  
JinSong Chen ◽  
TingDi Chen ◽  
...  
Keyword(s):  
Meteor Radar ◽  
Low Latitudes ◽  
Mlt Region

The characteristics of transforming coordinates from the geocentric system WGS-84 for the Mercator projection under low latitudes conditions

2018 ◽  
Vol 940 (10) ◽  
pp. 2-6
Author(s):  
J.A. Younes ◽  
M.G. Mustafin
Keyword(s):  
Coordinate System ◽  
Satellite System ◽  
Programming Algorithm ◽  
Low Latitude ◽  
Model Calculations ◽  
Mercator Projection ◽  
Low Latitudes ◽  
Rectangular Coordinates ◽  
Global Navigation Satellite ◽  
Coordination Methods

The issue of calculating the plane rectangular coordinates using the data obtained by the satellite observations during the creation of the geodetic networks is discussed in the article. The peculiarity of these works is in conversion of the coordinates into the Mercator projection, while the plane coordinate system on the base of Gauss-Kruger projection is used in Russia. When using the technology of global navigation satellite system, this task is relevant for any point (area) of the Earth due to a fundamentally different approach in determining the coordinates. The fact is that satellite determinations are much more precise than the ground coordination methods (triangulation and others). In addition, the conversion to the zonal coordinate system is associated with errors; the value at present can prove to be completely critical. The expediency of using the Mercator projection in the topographic and geodetic works production at low latitudes is shown numerically on the basis of model calculations. To convert the coordinates from the geocentric system with the Mercator projection, a programming algorithm which is widely used in Russia was chosen. For its application under low-latitude conditions, the modification of known formulas to be used in Saudi Arabia is implemented.

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