In:
Journal of the Atmospheric Sciences, American Meteorological Society, Vol. 78, No. 4 ( 2021-04), p. 1359-1386
Abstract:
We 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 ( λ z 〈 15 km) or period ( τ 〈 8 h) is applied. Gravity wave potential energy densities (GWPED) per unit volume ( E pV ) and per unit mass ( E pm ) 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 E pV 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 E pm compared to E pV . Lidar and SABER observations show that E pV 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 E pV decreases with altitude in nearly all cases. Corresponding E pV -scale heights from lidar are generally larger in winter compared to summer. Above ~55 km, E pV in summer is almost constant with altitude at both stations. The winter–summer difference of E pV scale heights is much smaller or absent in SABER and in reanalysis data.
Type of Medium:
Online Resource
ISSN:
0022-4928
,
1520-0469
DOI:
10.1175/JAS-D-20-0247.1
Language:
Unknown
Publisher:
American Meteorological Society
Publication Date:
2021
detail.hit.zdb_id:
218351-1
detail.hit.zdb_id:
2025890-2
SSG:
16,13
Bookmarklink
