Comparison of mesospheric winds from a high-altitude meteorological analysis system and meteor radar observations during the boreal winters of 2009–2010 and 2012–2013

McCormack, J. P.; Hoppel, K. W.; Kuhl, David D.; Wit, Rosmarie de; Stober, Gunter; Espy, P. J.; Baker, Nancy L.; Brown, Peter; Fritts, David C.; Jacobi, Ch.; Janches, Diego; Mitchell, N. J.; Ruston, Benjamin; Swadley, Steven D.; Viner, Kevin C.; Whitcomb, T.; Hibbins, R. E.

doi:10.1016/j.jastp.2016.12.007

Cited by 77 publications

(135 citation statements)

References 58 publications

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“…Over 3 million observations in each 6-hr window from radiosondes, pibals, dropsondes, driftsondes, land and ship surface observations, fixed and drifting buoys, aircraft observations, and several middle and lower atmospheric satellite mission-based winds, temperatures, and compositional data are used for the assimilation. Horizontal winds from NAVGEM-HA analyses were reported to compare well with the middle-, low-, and high-latitude SMR observations from both Northern and Southern hemispheres (McCormack et al, 2017). Additional technical details and validation of NAVGEM-HA wind analyses can be found in McCormack et al (2017).…”

Section: Navgem-hamentioning

confidence: 83%

Interhemispheric Meridional Circulation During Sudden Stratospheric Warming

Laskar

McCormack²,

Chau

et al. 2019

JGR Space Physics

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Although sudden stratospheric warming (SSW) is mainly a northern high‐latitude phenomena, there are several reports of a concomitant global dynamical response throughout the mesosphere and lower thermosphere. Published reports based on model simulations so far attributed such variabilities to changes in global circulation; however, there is no clear explanation of how all these regions are physically connected during SSW events. The present investigation uses wind observations from two ground‐based specular meteor radars over northern high latitudes and midlatitudes and global winds from a high‐altitude meteorological analysis system to characterize global mesospheric circulation anomalies for major SSW events during 2010 and 2013. During these events radar observations and the reanalysis winds exhibited strong southward winds over the two northern midlatitude and high‐latitude stations. By removing seasonal variability from the high‐altitude meteorological analyses, we show that these southward wind anomalies are indeed part of a larger global‐scale circulation, which gets set up during SSW and extend from the Northern pole to low‐latitude regions of Southern Hemisphere in the mesosphere and lower thermosphere altitudes. These results also offer a possible explanation of how low‐latitude ionospheric electrodynamics are influenced by the changes in the circulation set in during SSW at high latitudes.

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Section: Navgem-hamentioning

confidence: 83%

Interhemispheric Meridional Circulation During Sudden Stratospheric Warming

Laskar

McCormack²,

Chau

et al. 2019

JGR Space Physics

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“…Unlike the earlier NOGAPS‐ALPHA system, which used a three‐dimensional variational (3DVAR) DA algorithm that consolidates observations within a 6‐hr window and used static model covariance estimates, the hybrid 4DVAR NAVDAS‐AR in NAVGEM‐HA accounts for time‐varying observations within the 6‐hr window through a linear combination of climatological covariances and ensemble‐based model covariances to obtain more realistic estimates of forecast model uncertainties within the DA algorithm. The NAVGEM‐HA system was recently validated by McCormack et al () with multiple independent ground‐based medium frequency radar wind observations over the 2009–2010 and 2012–2013 Northern Hemisphere winters.…”

Section: Model Simulations Data Sets and Methodologymentioning

confidence: 99%

“…In this report we evaluate in detail the impact that SD nudging and the Stauffer and Seaman (, ) nudging technique (hereafter referred to as 4D Tendency nudging, where the 4D denotes three dimensions in space and one in time) have on short‐term TI variability. For this purpose, we performed a set of numerical experiments with the TIME‐GCM that constrain the meteorological fields in the stratosphere and mesosphere using NAVGEM‐HA (Navy Global Environmental Model a high‐altitude version; McCormack et al, ), during the 2010 boreal winter months that covers the 2010 SSW period from mid‐January to mid‐February. TIME‐GCM simulations constrained by NAVGEM‐HA winds and temperatures based on the SD nudging methodologies described by Maute et al (; hereafter referred to as SD zm ) and J. C. Wang et al (; hereafter referred to as SD full ) are presented and compared with those that employed the 4D Tendency nudging technique (hereafter referred to as 4D Tend ).…”

Section: Introductionmentioning

confidence: 99%

Evaluating Different Techniques for Constraining Lower Atmospheric Variability in an Upper Atmosphere General Circulation Model: A Case Study During the 2010 Sudden Stratospheric Warming

Jones

Drob

Siskind

et al. 2018

J Adv Model Earth Syst

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We analyze the effects specified dynamics (SD) and 4D Tendency nudging have on accurately reproducing the middle and upper atmospheric variability induced by the 2010 sudden stratospheric warming (SSW) event in the National Center for Atmospheric Research thermosphere‐ionosphere‐mesosphere‐electrodynamics general circulation model (TIME‐GCM). TIME‐GCM numerical experiments were performed using constrained middle atmospheric winds and temperatures from a high‐altitude version of the Navy Global Environmental Model to compare the previously implemented SD scheme, with the newly implemented 4D Tendency scheme. Model comparisons focused on zonal mean winds, composition, planetary waves, and tides in the thermosphere‐ionosphere system. Through 4D Tendency nudging we reveal that coupling coefficients of the one‐way SD coupling approach between the TIME‐GCM and observed SSW conditions were too strong. Prior implementations produced unusually strong vertical shears in the zonal mean winds in the mesosphere and lower thermosphere (MLT), where the model is free running. Differences in zonal mean MLT winds between SD and 4D Tendency nudging simulations resulted in migrating diurnal (DW1) and semidiurnal (SW2) tidal amplitude differences at lower thermospheric altitudes. The consequences of simulating different MLT dynamics using SD and 4D Tendency nudging in the overlaying ionosphere are reported and validated using electron density data from the Constellation Observing System for Meteorology, Ionosphere, and Climate satellites. Although we demonstrate that SD and 4D Tendency nudging techniques are approximately equivalent, results presented herein establish that 4D Tendency nudging has the added potential to identify physical model parameters that contribute to data‐model differences during the 2010 SSW.

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“…In general the statistical uncertainties tend to become larger when fewer meteors are included in the wind fit. A more detailed comparison of the obtained MR winds with the Navy Global Environmental Model (NAVGEM) is given in McCormack et al (2016).…”

Section: Meteor Radar Observation and Wind Analysismentioning

confidence: 99%

Exceptionally strong summer-like zonal wind reversal in the upper mesosphere during winter 2015/16

et al. 2017

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Abstract. The 2015/16 Northern Hemisphere winter season was marked by peculiarities in the circulation pattern in the high-latitude mesopause region. Wind measurements from the Andenes (69 • N, 13 • E) meteor radar show westward winds below 84 km and eastward winds above. This wind pattern in the zonal wind was observable between the end of December 2015 and the end of January 2016, i.e., conditions that are typical for the summer were found during winter. Additional meteor radar measurements at midlatitude stations did not show such a zonal wind reversal but indicate, together with the polar latitude stations, a reversal of the horizontal temperature gradient. This is confirmed by global satellite measurements. Therefore, it is plausible that the polar latitude summer-like zonal wind reversal in DecemberJanuary is in accordance with the reversed horizontal temperature gradient assuming a thermal wind balance between mid-and polar latitudes. The reversed horizontal temperature gradient itself is induced by stationary planetary waves at lower and midlatitudes in the mesosphere, leading to a weakening of the residual circulation above the European sector.

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Comparison of mesospheric winds from a high-altitude meteorological analysis system and meteor radar observations during the boreal winters of 2009–2010 and 2012–2013

Cited by 77 publications

References 58 publications

Interhemispheric Meridional Circulation During Sudden Stratospheric Warming

Interhemispheric Meridional Circulation During Sudden Stratospheric Warming

Evaluating Different Techniques for Constraining Lower Atmospheric Variability in an Upper Atmosphere General Circulation Model: A Case Study During the 2010 Sudden Stratospheric Warming

Exceptionally strong summer-like zonal wind reversal in the upper mesosphere during winter 2015/16

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