Details

Autor(en) / Beteiligte

• Lear, Emily J.
• Wright, Corwin J.
• Hindley, Neil P.
• Polichtchouk, Inna
• Hoffmann, Lars

Titel

Comparing Gravity Waves in a Kilometer‐Scale Run of the IFS to AIRS Satellite Observations and ERA5

Ist Teil von

• Journal of geophysical research. Atmospheres, 2024-06, Vol.129 (11), p.n/a

Ort / Verlag

Washington: Blackwell Publishing Ltd

Erscheinungsjahr

2024

Link zum Volltext

Quelle

Wiley Online Library

Beschreibungen/Notizen

• Atmospheric gravity waves (GWs) impact the circulation and variability of the atmosphere. Sub‐grid scale GWs, which are too small to be resolved, are parameterized in weather and climate models. However, some models are now available at resolutions at which these waves become resolved and it is important to test whether these models do this correctly. In this study, a GW resolving run of the European Center for Medium‐Range Weather Forecasts (ECMWF) Integrated Forecasting System (IFS), run with a 1.4 km average grid spacing (TCo7999 resolution), is compared to observations from the Atmospheric Infrared Sounder (AIRS) instrument, on NASA's Aqua satellite, to test how well the model resolves GWs that AIRS can observe. In this analysis, nighttime data are used from the first 10 days of November 2018 over part of Asia and surrounding regions. The IFS run is resampled with AIRS's observational filter using two different methods for comparison. The ECMWF ERA5 reanalysis is also resampled as AIRS, to allow for comparison of how the high resolution IFS run resolves GWs compared to a lower resolution model that uses GW drag parametrizations. Wave properties are found in AIRS and the resampled models using a multi‐dimensional S‐Transform method. Orographic GWs can be seen in similar locations at similar times in all three data sets. However, wave amplitudes and momentum fluxes in the resampled IFS run are found to be significantly lower than in the observations. This could be a result of horizontal and vertical wavelengths in the IFS run being underestimated. Plain Language Summary Small‐scale atmospheric waves, known as gravity waves (GWs), transport energy and momentum and affect the dynamics of the atmosphere. GWs in a high resolution run of the European Center for Medium‐Range Weather Forecasts Integrated Forecasting System (IFS) weather model are compared to those in observations from the Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite, to test how well these waves are resolved in the model. Nighttime data are compared over part of Asia and surrounding regions, during the first 10 days of November 2018. Since the high resolution IFS run has a higher vertical resolution, and a significantly higher horizontal resolution than the satellite observations, the model is resampled as if the satellite was viewing the model atmosphere. This removes GWs with horizontal and vertical wavelengths outside of the ranges that can be seen in the observations, allowing the data sets to be compared. Gravity waves formed by wind flowing over mountain ranges can be seen at similar times and in similar locations in the IFS run and observations, but wave amplitudes in the resampled IFS run are found to be significantly lower. Key Points A kilometer‐scale Integrated Forecasting System (IFS) run is resampled as Atmospheric Infrared Sounder (AIRS) using two different methods to allow for comparison of gravity wave (GW) properties GWs can be seen in the resampled IFS run and AIRS at similar times and locations Mean amplitudes in the resampled IFS run are found to be significantly lower than in the observations by a factor of ∼2.77