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Atmospheric pressure tides

General information:

Atmospheric surface pressure exhibits small but ubiquitous oscillations of magnitudes < 200 Pa at diurnal (S1) and semidiurnal (S2) periods. These well-known manifestations of solar tides are forced primarily by cyclic tropospheric water vapor and stratospheric ozone absorption, as well as  radiative and convective heating of the atmosphere from the Earth's surface. S2 tidal signals, dominated by Sun-locked, westward-travelling waves, appear with a marked zonal symmetry, whereas the diurnal pressure tide S1 has pronounced geographical modulations; cf. the figure below. By contrast, gravitationally driven tides dominate the short period dynamics in the oceans but are much smaller in the atmosphere due to the comperatively low density of air. Yet, surface pressure variations at lunar periods have received attention, particularly the semidiurnal L2 (or M2) oscillation, which represents the only wave in the atmosphere for which the forcing is, in principle, perfectly known. Hence, the tide has the potential to reveal details about the structure of the atmosphere itself, by comparing theory with observations as well as by numerical modeling.

Solar Tides

Mean annual diurnal (left panel) and semidiurnal (right panel) surface pressure tide amplitudes in units of (Pa) as deduced from globally distributed S1/S2 station tide estimates (updated version of Schindelegger and Ray, 2014).

 

Dataset description and download:

Schindelegger and Ray (2014) compiled more than 7100 mean annual S1/S2 in situ estimates from 20 years of station and marine pressure observations as archived within version 2 of the quality-controlled International Surface Pressure Databank. Building on this analysis, Schindelegger and Dobslaw (2016) inferred, through automated means, the lunar L2 tide and its seasonal variability from barometric time series at 2315 stations as contained in various international archives. Both solar and luanr tides were mapped to a global domain using multiquadric interpolation. In situ determinations and gridded variants are provided through the following links:

S1/S2 data and documentation

L2 data and documentation

 

References:

Schindelegger, M., Ray, R.D. (2014), Surface pressure tide climatologies deduced from a quality-controlled network of barometric observations. Monthly Weather Review, 142, 4872–4889, doi: 10.1175/MWR-D14-00217.1.

Schindelegger, M., Dobslaw, H. (2016), A global ground truth view of the lunar air pressure tide L2, Journal of Geophysical Research Atmospheres, 121, 95–110, doi: 10.1002/2015JD024243.
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