Equatorial wave analysis from SABER and ECMWF temperatures

Ern, Manfred; Preusse, Peter; Krebsbach, M.; Mlynczak, Martin G.; Russell, J. M.

doi:10.5194/acp-8-845-2008

Cited by 105 publications

(132 citation statements)

References 67 publications

Supporting

Mentioning

120

Contrasting

Order By: Relevance

“…7a shows amplitude variations that are strongly modulated by the QBO, with enhanced wave activity in periods of transition from easterly to westerly stratospheric wind (westerly shear zones). Similar results have been found by Randel and Wu (2005); Ern et al (2008); Alexander and Ortland (2010); Flannaghan and Fueglistaler (2013). These peaks in Kelvinwave activity are expected since Kelvin-wave energy is accumulated below the critical level, which is located near the zero-wind line.…”

Section: Temporal Variations In Kelvin-wave Activitysupporting

confidence: 85%

“…They include contributions of slow and quasi-stationary variations such as the annual cycle and interannual variability (El Niño-Southern Oscillation (ENSO) and the QBO). Sub-seasonal variability (periods shorter than 100 days) essentially contains signals of the MJO and equatorial waves (e.g., Wheeler and Kiladis, 1999;Ern et al, 2008). We isolate Kelvin-wave activity by selecting wave numbers k = +1 to +6, periods from 4 to 30 days, and equivalent depths from 8 to 240 m. After filtering, reverse fast Fourier transformations (FFTs) are applied to reconstruct atmospheric variability associated with individual types of waves.…”

Section: Gridding and Spectral Analysismentioning

confidence: 99%

“…Later, satellite temperature measurements provided a more global view on atmospheric dynamics. Equatorial atmospheric waves have been investigated using satellite data from Nimbus-7 LIMS (Limb Infrared Monitor of the Stratosphere; Salby et al, 1984), the Microwave Limb Sounder (MLS; Mote et al, 2002), SABER (Sounding of the Atmosphere using Broadband Emission Radiometry; Ern et al, 2008;Ern and Preusse, 2009), and High Resolution Dynamics Limb Sounder (HIRDLS; Alexander and Ortland, 2010). Furthermore, several studies on atmospheric Kelvin waves are based on analysis or reanalysis data from numerical weather prediction (NWP) centers (Tindall et al, 2006;Suzuki and Shiotani, 2008;Suzuki et al, 2010;Fujiwara et al, 2012;Flannaghan and Fueglistaler, 2013).…”

mentioning

confidence: 99%

See 2 more Smart Citations

Tropical temperature variability and Kelvin-wave activity in the UTLS from GPS RO measurements

2017

View full text Add to dashboard Cite

Abstract. Tropical temperature variability over 10-30 km and associated Kelvin-wave activity are investigated using GPS radio occultation (RO) data from January 2002 to December 2014. RO data are a powerful tool for quantifying tropical temperature oscillations with short vertical wavelengths due to their high vertical resolution and high accuracy and precision. Gridded temperatures from GPS RO show the strongest variability in the tropical tropopause region (on average 3 K 2 ). Large-scale zonal variability is dominated by transient sub-seasonal waves (2 K 2 ), and about half of subseasonal variance is explained by eastward-traveling Kelvin waves with periods of 4 to 30 days (1 K 2 ). Quasi-stationary waves associated with the annual cycle and interannual variability contribute about a third (1 K 2 ) to total resolved zonal variance. Sub-seasonal waves, including Kelvin waves, are highly transient in time. Above 20 km, Kelvin waves are strongly modulated by the quasi-biennial oscillation (QBO) in stratospheric zonal winds, with enhanced wave activity during the westerly shear phase of the QBO. In the tropical tropopause region, however, peaks of Kelvin-wave activity are irregularly distributed in time. Several peaks coincide with maxima of zonal variance in tropospheric deep convection, but other episodes are not evidently related. Further investigations of convective forcing and atmospheric background conditions are needed to better understand variability near the tropopause.

show abstract

Section: Temporal Variations In Kelvin-wave Activitysupporting

confidence: 85%

Section: Gridding and Spectral Analysismentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Tropical temperature variability and Kelvin-wave activity in the UTLS from GPS RO measurements

2017

View full text Add to dashboard Cite

show abstract

“…See also Preusse et al (2006), Eq. (10) in Ern et al (2008), and the discussion in Ern et al (2015).…”

Section: Satellite Observations Of Gravity Wave Amplitudes Momentum mentioning

confidence: 95%

“…For this purpose, longitude-time spectra are estimated for a fixed set of altitudes and latitudes. This procedure is described in detail in Ern et al (2011), and it accounts also for fast traveling planetary waves, such as shortperiod Kelvin waves (e.g., Ern et al, 2008;Ern and Preusse, 2009; or quasi 2-day waves (e.g., Ern et al, 2013). Tides, however, are removed separately, as described in Ern et al (2013).…”

Section: Satellite Observations Of Gravity Wave Amplitudes Momentum mentioning

confidence: 99%

Satellite observations of middle atmosphere gravity wave absolute momentum flux and of its vertical gradient during recent stratospheric warmings

Ern¹,

Trinh²,

Kaufmann³

et al. 2016

Atmos. Chem. Phys.

View full text Add to dashboard Cite

Abstract. Sudden stratospheric warmings (SSWs) are circulation anomalies in the polar region during winter. They mostly occur in the Northern Hemisphere and affect also surface weather and climate. Both planetary waves and gravity waves contribute to the onset and evolution of SSWs. While the role of planetary waves for SSW evolution has been recognized, the effect of gravity waves is still not fully understood, and has not been comprehensively analyzed based on global observations. In particular, information on the gravity wave driving of the background winds during SSWs is still missing.

show abstract

Interaction of gravity waves with the QBO: A satellite perspective

et al. 2014

Self Cite

View full text Add to dashboard Cite

One of the most important dynamical processes in the tropical stratosphere is the quasi-biennial oscillation (QBO) of the zonal wind. Still, the QBO is not well represented in weather and climate models. To improve the representation of the QBO in the models, a better understanding of the driving of the QBO by atmospheric waves is required. In particular, the contribution of gravity waves is highly uncertain because of the small horizontal scales involved, and there is still no direct estimation based on global observations. We derive gravity wave momentum fluxes from temperature observations of the satellite instruments HIRDLS and SABER. Momentum flux spectra observed show that particularly gravity waves with intrinsic phase speeds <30 m/s (vertical wavelengths <10 km) interact with the QBO. Gravity wave drag is estimated from vertical gradients of observed momentum fluxes and compared to the missing drag in the tropical momentum budget of ERA-Interim. We find reasonably good agreement between their variations with time and in their approximate magnitudes. Absolute values of observed and ERA-Interim missing drag are about equal during QBO eastward wind shear. During westward wind shear, however, observations are about 2 times lower than ERA-Interim missing drag. This could hint at uncertainties in the advection terms in ERA-Interim. The strong intermittency of gravity waves we find in the tropics might play an important role for the formation of the QBO and may have important implications for the parameterization of gravity waves in global models.

show abstract

Equatorial wave analysis from SABER and ECMWF temperatures

Cited by 105 publications

References 67 publications

Tropical temperature variability and Kelvin-wave activity in the UTLS from GPS RO measurements

Tropical temperature variability and Kelvin-wave activity in the UTLS from GPS RO measurements

Satellite observations of middle atmosphere gravity wave absolute momentum flux and of its vertical gradient during recent stratospheric warmings

Interaction of gravity waves with the QBO: A satellite perspective

Contact Info

Product

Resources

About