Characteristics of gravity waves resolved by ECMWF

Characteristics of African Easterly Waves Depicted by ECMWF Reanalyses for 1991-2000

Global survey of concentric gravity waves in AIRSimages and ECMWF analysis

Concentric gravity waves (CGWs) are atmospheric phenomena with ring-shape perturbations originating in the troposphere. They can propagate up to the ionosphere and thermosphere and dynamically couple the lower and upper atmosphere. In this study we developed a novel ring detection algorithm to extract CGWs from the Atmosphere Infrared Sounder (AIRS) radiance data and the European Center for Med...

Bending of Light by Gravity Waves

We describe the statistical properties of light rays propagating though a random sea of gravity waves and compare with the case for scalar metric perturbations from density inhomogeneities. For scalar fluctuations the deflection angle grows as the square-root of the path length D in the manner of a random walk, and the rms displacement of a ray from the unperturbed trajectory grows as D. For gr...

Statistical Characteristics of Gravity Waves Observed by an All-Sky Imager at Darwin, Australia

An all-sky airglow imager with a cooled-CCD camera, in place at Darwin (12.4◦S, 131.0◦E), Australia, since October 2001, has been used to obtain two-dimensional gravity wave images in the mesopause region. Using airglow images of the OI (557.7 nm, emission altitude ∼96 km) and OH-band (720-910 nm, ∼86 km) emissions obtained for October 2001 to August 2002, we investigated the wavelengths, phase...

The seasonal cycle of Kelvin waves in the ECMWF analyses

Atmospheric dynamics in the tropical regions is dominated by unbalanced motions in response to convective processes, found to vary on many temporal scales from diurnal to inter-seasonal and inter-annual scales. The gravest wave excited by convection is the Kelvin wave and it is characteristics by eastward and upward propagation away from its convective source. As it propagates vertically, a pac...