Lidar observations of the middle-atmosphere thermal tides at Mauna Loa (19.5°N): comparison with HRDI and GSWM

1998 ◽  
Author(s):  
Thierry Leblanc ◽  
I. S. McDermid ◽  
David A. Ortland
Keyword(s):  
Middle Atmosphere ◽  
Mauna Loa ◽  
Thermal Tides ◽  
Lidar Observations

scholarly journals Seasonal Cycle of Gravity Wave Potential Energy Densities from Lidar and Satellite Observations at 54° and 69°N

2021 ◽  
Vol 78 (4) ◽  
pp. 1359-1386
Author(s):  
Irina Strelnikova ◽  
Marwa Almowafy ◽  
Gerd Baumgarten ◽  
Kathrin Baumgarten ◽  
Manfred Ern ◽  
...  
Keyword(s):  
Potential Energy ◽  
Gravity Wave ◽  
Seasonal Cycle ◽  
Middle Atmosphere ◽  
Reanalysis Data ◽  
Vertical Wavelength ◽  
Wave Potential ◽  
Broadband Emission ◽  
The Difference ◽  
Lidar Observations

AbstractWe present gravity wave climatologies based on 7 years (2012–18) of lidar and Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) temperatures and reanalysis data at 54° and 69°N in the altitude range 30–70 km. We use 9452 (5044) h of lidar observations at Kühlungsborn [Arctic Lidar Observatory for Middle Atmosphere Research (ALOMAR)]. Filtering according to vertical wavelength (λz < 15 km) or period (τ < 8 h) is applied. Gravity wave potential energy densities (GWPED) per unit volume (EpV) and per unit mass (Epm) are derived. GWPED from reanalysis are smaller compared to lidar. The difference increases with altitude in winter and reaches almost two orders of magnitude around 70 km. A seasonal cycle of EpV with maximum values in winter is present at both stations in nearly all lidar and SABER measurements and in reanalysis data. For SABER and for lidar (with λ < 15 km) the winter/summer ratios are a factor of ~2–4, but are significantly smaller for lidar with τ < 8 h. The winter/summer ratios are nearly identical at both stations and are significantly larger for Epm compared to EpV. Lidar and SABER observations show that EpV is larger by a factor of ~2 at Kühlungsborn compared to ALOMAR, independent of season and altitude. Comparison with mean background winds shows that simple scenarios regarding GW filtering, etc., cannot explain the Kühlungsborn–ALOMAR differences. The value of EpV decreases with altitude in nearly all cases. Corresponding EpV-scale heights from lidar are generally larger in winter compared to summer. Above ~55 km, EpV in summer is almost constant with altitude at both stations. The winter–summer difference of EpV scale heights is much smaller or absent in SABER and in reanalysis data.

scholarly journals Winds and temperatures of the Arctic middle atmosphere during January measured by Doppler lidar

2017 ◽  
Author(s):  
Jens Hildebrand ◽  
Gerd Baumgarten ◽  
Jens Fiedler ◽  
Franz-Josef Lübken
Keyword(s):  
Energy Density ◽  
Large Scale ◽  
Middle Atmosphere ◽  
Polar Vortex ◽  
Unit Mass ◽  
The Arctic ◽  
Horizontal Wind ◽  
Data Set ◽  
Medium Range Weather Forecast ◽  
Lidar Observations

Abstract. We present an extensive data set of simultaneous temperature and wind measurements in the Arctic middle atmosphere. It consists of more than 300 h of Doppler Rayleigh lidar observations obtained during three January seasons 2012, 2014, and 2015, and covers the altitude range from 30 km up to about 85 km. The data set reveals large year-to-year variations of month-mean temperatures and winds, which in 2012 are caused by a sudden stratospheric warming. The temporal evolution of winds and temperatures after that warming are studied over a period of two weeks, showing an elevated stratopause and the reformation of the polar vortex. The month-mean temperatures and winds are compared to data extracted from the Integrated Forecast System of the European Centre for Medium-Range Weather Forecast (ECMWF) and the Horizontal Wind Model (HWM07). We find mean temperature, zonal wind, and meridional wind differences of up to 20 K, 20 m s−1, and 5 m s−1, respectively, between lidar observations and ECMWF data and of up to 30 m s−1 between lidar observations and HWM07 data. From the fluctuations of temperatures and winds within single nights we extract the potential and kinetic gravity wave energy density (GWED) per unit mass. It shows that the kinetic GWED is typically 5 to 10 times larger than the potential GWED, the total GWED increases with altitude with a scale height of ≈ 16 km. Since temporal fluctuations of winds and temperatures are underestimated in ECMWF, the total GWED is underestimated as well by a factor of 3 to 10 above 50 km altitude. Similarly we estimate the energy density per unit mass for large-scale waves LWED) from the fluctuations of night-mean temperatures and winds. The total LWED. The ratio of kinetic to potential LWED varies with altitude over two orders of magnitude. LWEDs from ECWMF data show similar results as the lidar data. From the comparison of GWED and LWED follows that large-scale waves carry about 2 to 6 times more energy than gravity waves.

scholarly journals Lidar observations of middle atmosphere temperature variability

1995 ◽  
Vol 13 (6) ◽  
pp. 648-655 ◽  
Author(s):  
G. P. Gobbi ◽  
C. Souprayen ◽  
F. Congeduti ◽  
G. Di Donfrancesco ◽  
A. Adriani ◽  
...  
Keyword(s):  
Solar Cycle ◽  
Middle Atmosphere ◽  
Atmospheric Temperature ◽  
Temperature Variability ◽  
Quasi Biennial Oscillation ◽  
Temperature Trends ◽  
Atmosphere Temperature ◽  
Reference Atmosphere ◽  
Lidar Observations ◽  
Biennial Oscillation

Abstract. We discuss 223 middle atmosphere lidar temperature observations. The record was collected at Frascati (42°N–13°E), during the 41-month period January 1989-May 1992, corresponding to the maximum of solar cycle 22. The choice of this interval was aimed at minimizing the temperature variability induced by the 11-year solar cycle. The average climatology over the 41-month period and comparison with a reference atmosphere (CIRA86) are presented. Monthly temperature variability over the full period, during opposite quasi-biennial oscillation phases and on a short-term scale (0.5–4 h), is analyzed. Results indicate the 50–55-km region as less affected by variability caused by the natural phenomena considered in the analysis. Due to this minimum in natural noise characterizing the atmospheric temperature just above the stratopause, observations of that region are well suited to the detection of possible temperature trends induced by industrial activities.

scholarly journals Statistical analysis of the mesospheric inversion layers over two symmetrical tropical sites: Réunion (20.8° S, 55.5° E) and Mauna Loa (19.5° N, 155.6° W)

2017 ◽  
Vol 35 (6) ◽  
pp. 1177-1194 ◽  
Author(s):  
Nelson Bègue ◽  
Nkanyiso Mbatha ◽  
Hassan Bencherif ◽  
René Tato Loua ◽  
Venkataraman Sivakumar ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Mean Amplitude ◽  
Temperature Inversion ◽  
Tropical Region ◽  
Height Range ◽  
Tropical Regions ◽  
Mauna Loa ◽  
Annual Component ◽  
Rayleigh Lidar ◽  
Lidar Observations

Abstract. In this investigation a statistical analysis of the characteristics of mesospheric inversion layers (MILs) over tropical regions is presented. This study involves the analysis of 16 years of lidar observations recorded at Réunion (20.8° S, 55.5° E) and 21 years of lidar observations recorded at Mauna Loa (19.5° N, 155.6° W) together with SABER observations at these two locations. MILs appear in 10 and 9.3 % of the observed temperature profiles recorded by Rayleigh lidar at Réunion and Mauna Loa, respectively. The parameters defining MILs show a semi-annual cycle over the two selected sites with maxima occurring near the equinoxes and minima occurring during the solstices. Over both sites, the maximum mean amplitude is observed in April and October, and this corresponds to a value greater than 35 K. According to lidar observations, the maximum and minimum mean of the base height ranged from 79 to 80.5 km and from 76 to 77.5 km, respectively. The MILs at Réunion appear on average ∼ 1 km thinner and ∼ 1 km lower, with an amplitude of ∼ 2 K higher than Mauna Loa. Generally, the statistical results for these two tropical locations as presented in this investigation are in fairly good agreement with previous studies. When compared to lidar measurements, on average SABER observations show MILs with greater amplitude, thickness and base altitudes of 4 K, 0.75 and 1.1 km, respectively. Taking into account the temperature error by SABER in the mesosphere, it can therefore be concluded that the measurements obtained from lidar and SABER observations are in significant agreement. The frequency spectrum analysis based on the lidar profiles and the 60-day averaged profile from SABER confirms the presence of the semi-annual oscillation where the magnitude maximum is found to coincide with the height range of the temperature inversion zone. This connection between increases in the semi-annual component close to the inversion zone is in agreement with most previously reported studies over tropics based on satellite observations. Results presented in this study confirm through the use of the ground-based Rayleigh lidar at Réunion and Mauna Loa that the semi-annual oscillation contributes to the formation of MILs over the tropical region.

Maintenance of Strong Rotational Winds in Venus' Middle Atmosphere by Thermal Tides

Science ◽  
1992 ◽  
Vol 257 (5070) ◽  
pp. 647-650 ◽  
Author(s):  
M. Newman ◽  
C. Leovy
Keyword(s):  
Middle Atmosphere ◽  
Thermal Tides

Rayleigh lidar observations of quasi-sinusoidal waves in the tropical middle atmosphere

2003 ◽  
Vol 108 (D24) ◽  
pp. n/a-n/a ◽  
Author(s):  
K. Rajeev ◽  
K. Parameswaran ◽  
M. N. Sasi ◽  
Geetha Ramkumar ◽  
B. V. Krishna Murthy
Keyword(s):  
Middle Atmosphere ◽  
Rayleigh Lidar ◽  
Lidar Observations
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