Climatological Westward‐Propagating Semidiurnal Tides and Their Composite Response to Sudden Stratospheric Warmings in SuperDARN and SD‐WACCM‐X

Zhang, Jiarong; Limpasuvan, Varavut; Orsolini, Yvan; Espy, P. J.; Hibbins, R. E.

doi:10.1029/2020jd032895

Cited by 19 publications

(38 citation statements)

References 60 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Zhang et al. (2021) also found improved agreement between high latitude zonal winds simulated by SD‐WACCM‐X and observed by radars in the first 2 weeks following SSW onset. However, as these particular major SSWs persist, the model winds in the MLT turn easterly after about 10 days but remain westerly in the observations.…”

Section: Climatology Of Model‐measurement Zonal Wind Differencesmentioning

confidence: 78%

“…One of the most widely used models is the Whole Atmosphere Community Climate Model (WACCM) (Marsh et al., 2013). Unfortunately, there is a limitation to using WACCM as a tool to study these processes in the polar winter mesopause region because it has a well‐known easterly (westward) wind bias in the polar winter upper mesosphere (e.g., Eswaraiah et al., 2016; Harvey et al., 2019; Hindley et al., 2022; Lieberman et al., 2015; Liu, 2016; Marsh et al., 2013; Noble et al., 2022; Rüfenacht et al., 2018; Smith, 2012; Yuan et al., 2008; Zhang et al., 2021). This bias is not unique to WACCM, and other comprehensive high‐top general circulation models with parameterized GWs show the same deficiencies in simulating the observed zonal wind structure (e.g., Wilhelm et al., 2019) in the winter upper mesosphere (e.g., Griffith et al., 2021; McCormack et al., 2017, 2021; McLandress et al., 2006; Pedatella, Fuller‐Rowell, et al., 2014; Schmidt et al., 2006).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Evaluation of Polar Winter Mesopause Wind in WACCMX+DART

et al. 2022

View full text Add to dashboard Cite

This work evaluates zonal winds in both hemispheres near the polar winter mesopause in the Whole Atmosphere Community Climate Model (WACCM) with thermosphere‐ionosphere eXtension combined with data assimilation using the Data Assimilation Research Testbed (DART) (WACCMX+DART). We compare 14 years (2006–2019) of WACCMX+DART zonal mean zonal winds near 90 km to zonal mean zonal winds derived from Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) geopotential height measurements during Arctic mid‐winter. 10 years (2008–2017) of WACCMX+DART zonal mean zonal winds are compared to SABER in the Antarctic mid‐winter. It is well known that WACCM, and WACCM‐X, zonal winds at the polar winter mesopause exhibit a strong easterly (westward) bias. One explanation for this is that the models omit higher order gravity waves (GWs), and thus the eastward drag caused by these GWs. We show for the first time that the model winds near the polar winter mesopause are in closer agreement with SABER observations when the winds near the stratopause are weak or reversed. The model and observed mesosphere and lower thermosphere winds agree most during dynamically disturbed times often associated with minor or major sudden stratospheric warming events. Results show that the deceleration of the stratospheric and mesospheric polar night jet allows enough eastward GWs to propagate into the mesosphere, driving eastward zonal winds that are in agreement with the observations. Thus, in both hemispheres, the winter polar night jet speed and direction near the stratopause may be a useful proxy for model fidelity in the polar winter upper mesosphere.

show abstract

Section: Climatology Of Model‐measurement Zonal Wind Differencesmentioning

confidence: 78%

Section: Introductionmentioning

confidence: 99%

Evaluation of Polar Winter Mesopause Wind in WACCMX+DART

et al. 2022

View full text Add to dashboard Cite

show abstract

“…A similar conclusion was made by Tomikawa et al (2012) who showed that a model with a top at 85 km can be sufficient to model the dynamics of elevated stratopause events. In addition, even in models extending into the lower thermosphere, the stratopause reforms -on average-at lower altitudes than 80 km: near 75 km in the composite of 13 ESEs in SD-WACCM (extending up to 140 km) (Limpasuvan et al, 2016), or in the composite of 9 ESEs in SD-WACCM-X (extending up to 400 km) (Zhang et al, 2021).…”

Section: Model Data and Methodsmentioning

confidence: 99%

Elevated stratopause events in the current and a future climate: A chemistry-climate model study

Scheffler

Ayarzagüena

Orsolini

et al. 2022

Journal of Atmospheric and Solar-Terrestrial Physics

Self Cite

View full text Add to dashboard Cite

The characteristics and driving mechanisms of Elevated Stratopause Events (ESEs) are examined in simulations of the ECHAM/MESSy Atmospheric Chemistry (EMAC) chemistry-climate model under present and projected climate conditions. ESEs develop after sudden stratospheric warmings (SSWs) in boreal winter. While the stratopause descends during SSWs, it is reformed at higher altitudes after the SSWs, leading to ESEs in years with a particularly high new stratopause. EMAC reproduces well the frequency and main characteristics of observed ESEs. ESEs occur in 24% of the winters, mostly after major SSWs. They develop in stable polar vortices due to a persistent tropospheric wave forcing leading to a prolonged zonal wind reversal in the lower stratosphere. By wave filtering, this enables a faster re-establishment of the mesospheric westerly jet, polar downwelling and a higher stratopause. We find the presence of a westward-propagating wavenumber-1 planetary wave in the mesosphere following the onset, consistent with in-situ generation by large-scale instability. By the end of the 21st century, the number of ESEs is projected to increase, mainly due to a sinking of the original stratopause after strong tropospheric wave forcing and planetary wave dissipation at lower levels. Future ESEs develop preferably in more intense and cold polar vortices, and tend to be shorter. While in the current climate, planetary wavenumber-2 contributes to the forcing of ESEs, future wave forcing is dominated by wavenumber-1 activity as a result of climate change. Hence, a persistent wave forcing seems to be more relevant for the development of an ESE than the wavenumber decomposition of the forcing.

show abstract

“…The numerical study of the SW2 tide has a long history (e.g., Forbes & Garrett, 1979). Nevertheless, open questions remain about the mechanisms governing the tide's seasonal and short‐term variability (Conte et al., 2018; G. Liu et al., 2021; Pedatella et al., 2020; Zhang et al., 2021). Many recent studies are in part driven by the increasing availability of high‐altitude and tide‐resolving general circulation models.…”

Section: Introductionmentioning

confidence: 99%

The Mid‐ to High‐Latitude Migrating Semidiurnal Tide: Results From a Mechanistic Tide Model and SuperDARN Observations

et al. 2022

Self Cite

View full text Add to dashboard Cite

Atmospheric tides are global-scale waves whose periods are an integer fraction of a solar day (Chapman & Lindzen, 1970). The tides are forced primarily by radiative and latent heating effects in the lower atmosphere (Hagan, 1996), but obtain their largest amplitudes in the mesosphere-lower-thermosphere (MLT) region (80-120 km altitude). There they are expressed as pronounced oscillations in a broad range of atmospheric fields, such as density, pressure, and wind. The migrating tides are those tides which follow the apparent motion of the sun, having a longitudinal zonal wavenumber (S) and latitudinal spherical harmonic (Hough mode) structure. In the current work, the focus lies on the migrating semidiurnal (SW2; for Semidiurnal, Westward S = 2) tide. The SW2 tidal winds maximize in the mid-and high-latitude MLT (Manson et al., 2002;Wu et al., 2011), where they form a major source of day-to-day and inter-seasonal variability of the MLT-ionosphere system (Arras et al., 2009;G. Shepherd et al., 1998;Smith, 2012). The SW2 tide is recognized as an important vertical coupling mechanism (Forbes, 2009;Pedatella & Forbes, 2010), and as a contributing factor to the vertical mixing and energy budget of the upper atmosphere (Becker, 2017;Forbes et al., 1993).The numerical study of the SW2 tide has a long history (e.g., Forbes & Garrett, 1979). Nevertheless, open questions remain about the mechanisms governing the tide's seasonal and short-term variability (

show abstract

Climatological Westward‐Propagating Semidiurnal Tides and Their Composite Response to Sudden Stratospheric Warmings in SuperDARN and SD‐WACCM‐X

Cited by 19 publications

References 60 publications

Evaluation of Polar Winter Mesopause Wind in WACCMX+DART

Evaluation of Polar Winter Mesopause Wind in WACCMX+DART

Elevated stratopause events in the current and a future climate: A chemistry-climate model study

The Mid‐ to High‐Latitude Migrating Semidiurnal Tide: Results From a Mechanistic Tide Model and SuperDARN Observations

Contact Info

Product

Resources

About