Derivation of gravity wave potential energy density from NDMC measurements

2016 ◽  
Vol 138-139 ◽  
pp. 32-46 ◽  
Author(s):  
Sabine Wüst ◽  
Verena Wendt ◽  
Carsten Schmidt ◽  
Sabrina Lichtenstern ◽  
Michael Bittner ◽  
...  
2021 ◽  
Author(s):  
Irina Strelnikova ◽  
Gerd Baumgarten ◽  
Kathrin Baumgarten ◽  
Manfred Ern ◽  
Michael Gerding ◽  
...  

<p><span>We present results of seven years of gravity waves (GW) observations between 2012 and 2018. The measurements were conducted by ground-based lidars in Kühlungsborn (54°N, 12°E) and at ALOMAR (69°N, 16°E). Our analysis technique includes different types of filtering which allow for selection of different ranges from the entire GW-spectrum. We studied </span><span>wave</span><span> properties as a function of altitude and location and summarized the results in monthly and seasonally mean profiles. </span><span>Complementary</span><span> data is taken from the satellite-based SABER instrument. Additionally, we consistently applied our analysis technique to the reanalyses data from MERRA-2 and ERA-5. </span></p><p>A<span> seasonal cycle of </span><span>gravity wave potential energy density </span><span>(</span><span>GWPED</span><span>)</span><span> with maximum values in winter is present at both stations in nearly all lidar/SABER measurements and in reanalysis data. For SABER and for lidar the winter </span><span>to </span><span>summer ratios are a factor of </span><span>about 3</span><span>. The winter </span><span>to </span><span>summer ratios are nearly identical at both stations. </span><span>GWPED</span><span>s</span><span> from reanalysis are smaller compared to lidar. The difference increases with altitude in winter and reaches almost two orders of magnitude around 70 km.</span></p><p><span>GWPEDs per volume</span><span> decrease</span><span>s</span><span> with height </span><span>differently for the winter and summer seasons,</span><span> irrespective of filtering method and location. </span><span>In summer for altitudes above roughly 5</span><span>0</span><span> km, GWPED is nearly constant or even increases with height. </span><span>T</span><span>his feature is very pronounced at ALOMAR and to a lesser extent also </span><span>at</span><span> Kühlungsborn. This behavior is seen </span><span>by both, lidar and SABER</span><span>. The observed variation of GWPED with height can not be explained by conservation of wave action alone. </span></p><p><span>The </span><span>GWPED at K</span><span>ü</span><span>hlungsborn is significantly larger compared to ALOMAR. This observation is opposite to simple scenarios which take into account the potential impact of background winds on GW filtering and Doppler shifts of vertical wavelengths and periods. </span></p><p><span>W</span><span>e present results of </span><span>observations and</span><span> analyses </span><span>and suggest geophysical explanations of our findings.</span></p><p> </p><p> </p>


2021 ◽  
Vol 78 (4) ◽  
pp. 1359-1386
Author(s):  
Irina Strelnikova ◽  
Marwa Almowafy ◽  
Gerd Baumgarten ◽  
Kathrin Baumgarten ◽  
Manfred Ern ◽  
...  

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.


2017 ◽  
Author(s):  
Sabine Wüst ◽  
Michael Bittner ◽  
Jeng-Hwa Yee ◽  
Martin G. Mlynczak ◽  
James M. Russell III

Abstract. In and near the Alpine region, the most dense sub-network of identical NDMC instruments (Network for the Detection of Mesospheric Change, http://wdc.dlr.de/ndmc) can be found: five stations are equipped with OH*-spectrometers which deliver a time series of mesopause temperature each cloudless or only partially cloudy night. These measurements are suitable for the derivation of the density of gravity wave potential energy—knowledge about the Brunt-Väisälä frequency provided. However, OH*-spectrometers do not deliver vertically-resolved temperature information, which are necessary for the calculation of the Brunt-Väisälä frequency. Co-located measurements or climatological values are needed. We use 14 years of satellite-based temperature data (TIMED-SABER, 2002–2015) to investigate the inter- and intra-annual variability of the Brunt-Väisälä frequency at the OH*-layer height between 43.93–48.09° N and 5.71–12.95° E and provide a climatology.


2022 ◽  
Vol 6 (0) ◽  
pp. 0-0
Author(s):  
Yue Wu ◽  
◽  
Zheng Sheng ◽  
and XinJie Zuo ◽  
◽  
...  

2020 ◽  
Vol 501 (1) ◽  
pp. 1072-1077
Author(s):  
G Manju ◽  
N Mridula

ABSTRACT First estimations of Gravity Wave Potential Energy (GWPE) for Martian thermosphere are reported herein using the height profile of CO2 density derived temperature fluctuations for different Martian seasons during the 33rd Martian year. Explicit diurnal evolution of GWPE (52⁰ to 73⁰ latitude bin) with a post sunset maximum is delineated for summer. The higher values of GWPE are observed during morning, compared to post-midnight (35⁰ to 55⁰ latitude bin) for summer. As latitude increases from 16⁰ to 45⁰, GWPE (1-4 LT bin) is found to be nearly doubled for summer. Further, GWPE estimates in autumn are 6 times higher during night compared to day (-45⁰ to -72⁰ latitude bin) and day time (-53⁰ to -72⁰ latitude bin) GWPE is much lower in autumn compared to spring for all longitudes. Overall, from the available data, southern autumn daytime periods appear better suited for aero-braking operations of Martian landing missions.


Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 311
Author(s):  
Shih-Sian Yang ◽  
Chen-Jeih Pan ◽  
Uma Das

Atmospheric gravity waves play a crucial role in affecting atmospheric circulation, energy transportation, thermal structure, and chemical composition. Using ERA5 temperature data, the present study investigates the tropospheric to the lower mesospheric gravity wave potential energy (EP) over the equatorial region to understand the vertical coupling of the atmosphere. EP is mainly controlled by two factors. The first is zonal wind through wave–mean flow interactions, and thus EP has periodic variations that are correlated to the zonal wind oscillations and enhances around the altitudes of zero-wind shears where the zonal wind reverses. The second is the convections caused by atmospheric circulations and warm oceans, resulting in longitudinal variability in EP. The lower stratospheric and the lower mesospheric EP are negatively correlated. However, warm oceanic conditions can break this wave energy coupling and further enhance the lower mesospheric EP.


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