Inter-annual variation of gravity waves in the Arctic and Antarctic winter middle atmosphere

Jiang, Jonathan H.; Eckermann, Stephen D.; Wu, Dong L.; Wang, Ding Yi

doi:10.1016/j.asr.2005.09.036

Cited by 20 publications

(33 citation statements)

References 24 publications

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“…[58] These well-known orographic features have been analyzed in a large number of observational and modeling studies [Bacmeister et al, 1990;Wu and Jiang, 2002;Jiang et al, 2005Jiang et al, , 2006Wu et al, 2006;Alexander and Teitelbaum, 2007;Baumgaertner and McDonald, 2007;Vincent et al, 2007;Hertzog et al, 2008;Alexander et al, 2009b;de la Torre et al, 2012]. In particular, Plougonven et al [2008] reported occurrence frequency estimates of gravity wave events over the Antarctic Peninsula that compare well with those reported here.…”

Section: Antarcticasupporting

confidence: 63%

A global view of stratospheric gravity wave hotspots located with Atmospheric Infrared Sounder observations

2013

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[1] The main aim of this study is to find and classify hotspots of stratospheric gravity waves on a global scale. The analysis is based on a 9 year record (2003 to 2011) of radiance measurements by the Atmospheric Infrared Sounder (AIRS) aboard NASA's Aqua satellite. We detect gravity waves based on 4.3 mm brightness temperature variances. Our method focuses on peak events, i.e., strong gravity wave events for which the local variance considerably exceeds background levels. We estimate the occurrence frequencies of these peak events for different seasons and time of day and use the results to find local maxima or "hotspots." In addition, we use AIRS radiances at 8.1 mm to simultaneously detect convective events, including deep convection in the tropics and mesoscale convective systems at middle latitudes. We classify the gravity wave sources based on seasonal occurrence frequencies for convection, but also by means of time series analyses and topographic data. Our study reproduces well-known hotspots of gravity waves, e.g., the Andes and the Antarctic Peninsula. However, the high horizontal resolution of the AIRS observations also allows us to locate numerous mesoscale hotspots, which are partly unknown or poorly studied so far. Most of these mesoscale hotspots are found near orographic features like mountain ranges, coasts, lakes, deserts, or isolated islands. This study will help to select promising regions and seasons for future case studies of gravity waves.Citation: Hoffmann, L., X. Xue, and M. J. Alexander (2013), A global view of stratospheric gravity wave hotspots located with Atmospheric Infrared Sounder observations,

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Section: Antarcticasupporting

confidence: 63%

A global view of stratospheric gravity wave hotspots located with Atmospheric Infrared Sounder observations

2013

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“…It is generally accepted that the GWs in the stratosphere and mesosphere are related to the GW sources (orography, convection, jet/front systems, and planetary wave breaking) and propagation conditions (background winds and atmospheric stabilities) [ Nappo , ; Fritts and Alexander , ; Hertzog et al ., ; Jiang et al ., , ; John and Kumar , ; X. Liu et al ., ; Plougonven and Zhang , ; Thurairajah et al ., ; Ern et al ., ]. At the southern higher latitudes, the GWs generated by orography are comparable to the nonorographic GWs on zonal average, as revealed by Hertzog et al .…”

Section: Discussionmentioning

confidence: 99%

Variations of global gravity waves derived from 14 years of SABER temperature observations

Xiao

Yue

et al. 2017

JGR Atmospheres

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The global gravity wave (GW) potential energy (PE) per unit mass is derived from SABER (Sounding of the Atmosphere using Broadband Emission Radiometry) temperature profiles over the past 14 years (2002–2015). Since the SABER data cover longer than one solar cycle, multivariate linear regression is applied to calculate the trend (means linear trend from 2002 to 2015) of global GW PE and the responses of global GW PE to solar activity, to QBO (quasi‐biennial oscillation) and to ENSO (El Niño–Southern Oscillation). We find a significant positive trend of GW PE at around 50°N during July from 2002 to 2015, in agreement with ground‐based radar observations at a similar latitude but from 1990 to 2010. Both the monthly and the deseasonalized trends of GW PE are significant near 50°S. Specifically, the deseasonalized trend of GW PE has a positive peak of 12–15% per decade at 40°S–50°S and below 60 km, which suggests that eddy diffusion is increasing in some places. A significant positive trend of GW PE near 50°S could be due to the strengthening of the polar stratospheric jets, as documented from Modern Era Retrospective‐analysis for Research and Applications wind data. The response of GW PE to solar activity is negative in the lower and middle latitudes. The response of GW PE to QBO (as indicated by 30 hPa zonal winds over the equator) is negative in the tropical upper stratosphere and extends to higher latitudes at higher altitudes. The response of GW PE to ENSO (as indicated by the Multivariate ENSO Index) is positive in the tropical upper stratosphere.

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“…Even excluding the mean momentum flux estimates at 94.5 km (where meteor counts are high, but tidal modulation is very strong), these results suggest that strong forcing of GWs that penetrate into the MLT continues within the “hot spot” centered over the Drake Passage into September. Additional support for this is provided by the continuing strength of the stratospheric jet, with even stronger winds at ∼30 km in September than in June (see Figure 11) and high GW variances seen in MLS data in the upper stratosphere and mesosphere often extending into September [see Wu and Jiang , 2002; Jiang et al , 2006].…”

Section: Monthly Mean and Composite‐day Winds Tides And Gw Momentummentioning

confidence: 99%

“…[37] These results might be expected, however, given the location of SAAMER within the northern edge of the region spanning the southern Andes, the Drake Passage, and the Antarctic Peninsula [McLandress et al, 2000;Jiang et al, 2002Jiang et al, , 2006Wu and Jiang, 2002;Wu, 2004;Ern et al, 2004] which exhibits one of the, if not the, largest enhancement of GW amplitudes and implied momentum fluxes extending into the MLT under winter conditions of any site on Earth. These enhancements are apparently due to very strong GW excitation by sources in the lower atmosphere.…”

Section: June 2008 Datamentioning

confidence: 99%

Southern Argentina Agile Meteor Radar: Initial assessment of gravity wave momentum fluxes

2010

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[1] The Southern Argentina Agile Meteor Radar (SAAMER) was installed on Tierra del Fuego (53.8°S) in May 2008 and has been operational since that time. This paper describes tests of the SAAMER ability to measure gravity wave momentum fluxes and applications of this capability during different seasons. Test results for specified mean, tidal, and gravity wavefields, including tidal amplitudes and gravity wave momentum fluxes varying strongly with altitude and/or time, suggest that the distribution of meteors throughout the diurnal cycle and averaged over a month allows characterization of both monthly mean profiles and diurnal variations of the gravity wave momentum fluxes. Applications of the same methods for real data suggest confidence in the monthly mean profiles and the composite day diurnal variations of gravity wave momentum fluxes at altitudes where meteor counts are sufficient to yield good statistical fits to the data. Monthly mean zonal winds and gravity wave momentum fluxes exhibit anticorrelations consistent with those seen at other midlatitude and high-latitude radars during austral spring and summer, when no strong local gravity wave sources are apparent. When stratospheric variances are significantly enhanced over the Drake Passage "hot spot" during austral winter, however, MLT winds and momentum fluxes over SAAMER exhibit very different correlations that suggest that MLT dynamics are strongly influenced by strong local gravity wave sources within this "hot spot." SAAMER measurements of mean zonal and meridional winds at these times and their differences from measurements at a conjugate site provide further support for the unusual momentum flux measurements.

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Inter-annual variation of gravity waves in the Arctic and Antarctic winter middle atmosphere

Cited by 20 publications

References 24 publications

A global view of stratospheric gravity wave hotspots located with Atmospheric Infrared Sounder observations

A global view of stratospheric gravity wave hotspots located with Atmospheric Infrared Sounder observations

Variations of global gravity waves derived from 14 years of SABER temperature observations

Southern Argentina Agile Meteor Radar: Initial assessment of gravity wave momentum fluxes

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