A global model of meteoric sodium

A global model of sodium in the mesosphere and lower thermosphere has been developed within the framework of the National Center for Atmospheric Research's Whole Atmosphere Community Climate Model (WACCM). The standard fully interactive WACCM chemistry module has been augmented with a chemistry scheme that includes nine neutral and ionized sodium species. Meteoric ablation provides the source of sodium in the model and is represented as a combination of a meteoroid input function (MIF) and a parameterized ablation model. The MIF provides the seasonally and latitudinally varying meteoric flux which is modeled taking into consideration the astronomical origins of sporadic meteors and considers variations in particle entry angle, velocity, mass, and the differential ablation of the chemical constituents. WACCM simulations show large variations in the sodium constituents over time scales from days to months. Seasonality of sodium constituents is strongly affected by variations in the MIF and transport via the mean meridional wind. In particular, the summer to winter hemisphere flow leads to the highest sodium species concentrations and loss rates occurring over the winter pole. In the Northern Hemisphere, this winter maximum can be dramatically affected by stratospheric sudden warmings. Simulations of the January 2009 major warming event show that it caused a short-term decrease in the sodium column over the polar cap that was followed by a factor of 3 increase in the following weeks. Overall, the modeled distribution of atomic sodium in WACCM agrees well with both ground-based and satellite observations. Given the strong sensitivity of the sodium layer to dynamical motions, reproducing its variability provides a stringent test of global models and should help to constrain key atmospheric variables in this poorly sampled region of the atmosphere. Key Points The first global model of mesospheric sodium has been developed Model includes new description of the meteoroid input function Meridional winds and stratospheric sudden warnings affect the sodium column.

[1]  Daniel R. Marsh,et al.  Climate change from 1850 to 2005 simulated in CESM1(WACCM) , 2013 .

[2]  Anne K. Smith,et al.  Signature of an overturning gravity wave in the mesospheric sodium layer: Comparison of a nonlinear photochemical‐dynamical model and lidar observations , 2006 .

[3]  E. Llewellyn,et al.  Retrieval of global mesospheric sodium densities from the Odin satellite , 2007 .

[4]  P. Batista,et al.  Negligible long‐term temperature trend in the upper atmosphere at 23°S , 2004 .

[5]  D. Fussen,et al.  A global climatology of the mesospheric sodium layer from GOMOS data during the 2002–2008 period , 2010 .

[6]  Jiyao Xu,et al.  Perturbations of the sodium layer: controlled by chemistry or dynamics? , 2003 .

[7]  Anne K. Smith,et al.  Global Dynamics of the MLT , 2012, Surveys in Geophysics.

[8]  G. Kopp,et al.  A new, lower value of total solar irradiance: Evidence and climate significance , 2011 .

[9]  J. Stegman,et al.  Satellite measurements of the global mesospheric sodium layer , 2007 .

[10]  G. Barrot,et al.  A global climatology of the mesospheric sodium layer from GOMOS data during the 2002-2008 period , 2010 .

[11]  C. Gardner,et al.  Seasonal variations of the Na and Fe layers at the South Pole and their implications for the chemistry and general circulation of the polar mesosphere , 2005 .

[12]  T. Diehl,et al.  Sensitivity of chemical tracers to meteorological parameters in the MOZART-3 chemical transport model , 2007 .

[13]  Rolando R. Garcia,et al.  Long‐term middle atmospheric influence of very large solar proton events , 2009 .

[14]  Ronald F. Woodman,et al.  Modeling the global micrometeor input function in the upper atmosphere observed by high power and large aperture radars , 2006 .

[15]  E. Kopp On the abundance of metal ions in the lower ionosphere , 1997 .

[16]  B. Thurairajah,et al.  Wind and temperature response of midlatitude mesopause region to the 2009 Sudden Stratospheric Warming , 2012 .

[17]  D. Janches,et al.  A comparison of detection sensitivity between ALTAIR and Arecibo meteor observations: Can high power and large aperture radars detect low velocity meteor head-echoes , 2008 .

[18]  Chester S. Gardner,et al.  Structure of the mesospheric Na layer at 40° N latitude: Seasonal and diurnal variations , 1999 .

[19]  R. Garcia,et al.  Mesospheric Na layer at 40°N: Modeling and observations , 1999 .

[20]  Greg Kopp,et al.  SORCE Contributions to New Understanding of Global Change and Solar Variability , 2005 .

[21]  Jonathan T. Fentzke,et al.  A semi‐empirical model of the contribution from sporadic meteoroid sources on the meteor input function in the MLT observed at Arecibo , 2008 .

[22]  D. Marsh,et al.  WACCM simulations of the mean circulation and trace species transport in the winter mesosphere , 2011 .

[23]  Y. Morton,et al.  Morphology of nighttime ion, potassium and sodium layers in the meteor zone above Arecibo , 2005 .

[24]  R. Neale,et al.  The Mean Climate of the Community Atmosphere Model (CAM4) in Forced SST and Fully Coupled Experiments , 2013 .

[25]  Fan Yi,et al.  A global atmospheric model of meteoric iron , 2013 .

[26]  S. Schubert,et al.  MERRA: NASA’s Modern-Era Retrospective Analysis for Research and Applications , 2011 .

[27]  John M. C. Plane,et al.  A chemical model of meteoric ablation , 2008 .

[28]  Jiyao Xu,et al.  Studies of gravity wave–induced fluctuations of the sodium layer using linear and nonlinear models , 2004 .

[29]  E. O. Hulburt,et al.  SORCE CONTRIBUTIONS TO NEW UNDERSTANDING OF GLOBAL CHANGE AND SOLAR VARIABILITY , 2005 .

[30]  Reconciling modeled and observed temperature trends over Antarctica , 2012 .

[31]  Xinzhao Chu,et al.  Removal of Meteoric Iron on Polar Mesospheric Clouds , 2004, Science.

[32]  Rolando R. Garcia,et al.  Modeling the whole atmosphere response to solar cycle changes in radiative and geomagnetic forcing , 2007 .

[33]  Dieter Bilitza,et al.  INTERNATIONAL REFERENCE IONOSPHERE 2000: EXAMPLES OF IMPROVEMENTS AND NEW FEATURES , 2003 .

[34]  Amy H. Butler,et al.  El Niño, La Niña, and stratospheric sudden warmings: A reevaluation in light of the observational record , 2011 .

[35]  D. Pancheva,et al.  Aeronomy of the earth's atmosphere and ionosphere , 2011 .

[36]  U. Zahn,et al.  Average properties of the sodium density distribution as observed at 69°N latitude in winter , 1988 .

[37]  J. D. Vance,et al.  Eight‐year climatology of nocturnal temperature and sodium density in the mesopause region (80 to 105 km) over Fort Collins, Co (41°N, 105°W) , 2000 .

[38]  J. Plane A time-resolved model of the mesospheric Na layer: constraints on the meteor input function , 2004 .

[39]  Douglas O. ReVelle,et al.  Meteor Phenomena and Bodies , 1998 .

[40]  J. Plane The role of sodium bicarbonate in the nucleation of noctilucent clouds , 2000 .

[41]  D. Marsh,et al.  Numerical simulations of the three-dimensional distribution of meteoric dust in the mesosphere and upper stratosphere , 2008 .

[42]  Fan Yi,et al.  Seasonal variations of the nocturnal mesospheric Na and Fe layers at 30°N , 2009 .

[43]  J. Plane Cosmic dust in the earth's atmosphere. , 2012, Chemical Society reviews.

[44]  P. Batista,et al.  The diurnal variation of atmospheric sodium , 1982 .

[45]  Takuji Nakamura,et al.  The Meteoroid Input Function and predictions of mid-latitude meteor observations by the MU radar , 2013 .

[46]  D. Marsh Chemical–Dynamical Coupling in the Mesosphere and Lower Thermosphere , 2011 .

[47]  M. Rapp,et al.  Meteoric smoke particle properties derived using dual-beam Arecibo UHF observations of D-region spectra during different seasons , 2009 .

[48]  D. Janches,et al.  First observation of micrometeoroid differential ablation in the atmosphere , 2009 .