Did Tsunami‐Launched Gravity Waves Trigger Ionospheric Turbulence over Arecibo?

[1] We report on measurements of ionospheric plasma dynamics conducted at the Arecibo Observatory between 20:00 and 24:00 local time (LT) on December 25 and 26, 2004 using the 430 MHz incoherent scatter radar (ISR). For interpretive purposes these measurements are supported by data from two nearby ionosondes and Global Positioning System (GPS) satellites. The ISR detected different ionospheric behaviors during the vertical-transmission periods on the consecutive, magnetically quiet nights. On the night of December 25 the ionosphere descended smoothly and spread F signatures faded. For about two hours on the following evening the bottomside ionosphere rose by ∼50 km, inducing plasma irregularities and intense spread F. Alternating cycles of bottom-side plasma rising and falling persisted through the remainder of the experiments. We postulate that this sinusoidal behavior is a response to gravity waves propagating above Puerto Rico. Nearly simultaneous data from two nearby stations show that GPS signals were modified by variations in total electron content (TEC) indicating the presence of traveling ionospheric disturbances (TIDs). The December 26 experiments were conducted about a day after an MW = 9.2 earthquake launched tsunami waves first across the Indian, then into the Atlantic and Pacific Oceans. We suggest that coupling at the tsunami sea-air interface launched gravity waves that propagated for great distances beneath the mesopause. GPS data recorded TEC variation in Asia, Europe, and the Caribbean, suggesting that TIDs were induced on a global scale at the wake of tsunami-launched gravity waves. Energy from imperfectly ducted gravity waves leaked into the ionosphere, partially over Puerto Rico. The wind-velocity field of these gravity waves caused local ionospheric plasma to rise, seeding bottomside irregularities via the generalized Rayleigh-Taylor instability.

[1]  M. Kelley,et al.  Collisional interchange instability 2. A comparison of the numerical simulations with the in situ experimental data , 1987 .

[2]  J. Meriwether,et al.  Evidence for orographic wave heating in the equatorial thermosphere at solar maximum , 1996 .

[3]  S. Francis.  Acoustic-gravity modes and large-scale traveling ionospheric disturbances of a realistic, dissipative atmosphere , 1973 .

[4]  Optically Pumped Silicon Lases in the Near-Infrared , 2005 .

[5]  J. H. Elder,et al.  High‐resolution studies of atmosphere‐ionosphere coupling at Arecibo Observatory, Puerto Rico , 1997 .

[6]  J. Holton,et al.  A Numerical Study of Three-Dimensional Gravity Waves Triggered by Deep Tropical Convection and Their Role in the Dynamics of the QBO , 2000 .

[7]  R. A. Behnke,et al.  F layer height bands in the nocturnal ionosphere over Arecibo , 1979 .

[8]  Philippe Lognonné,et al.  Acoustic waves generated from seismic surface waves: propagation properties determined from Doppler sounding observations and normal-mode modelling , 2004 .

[9]  M. Larsen,et al.  Arecibo observations of ionospheric perturbations associated with the passage of Tropical Storm Odette , 2006 .

[10]  R. Livingston,et al.  Equatorial plasma bubbles: vertically elongated wedges from the bottomside F layer. Technical report , 1981 .

[11]  E. Dewan,et al.  Simultaneous Observations of Mesospheric Gravity Waves and Sprites Generated by a Midwestern Thunderstorm , 2003 .

[12]  Takuji Nakamura,et al.  Convectively generated mesoscale gravity waves simulated throughout the middle atmosphere , 2002 .

[13]  Chien-Ping Lee,et al.  Ionospheric GPS total electron content (TEC) disturbances triggered by the 26 December 2004 Indian Ocean tsunami , 2006 .

[14]  H. Kanamori,et al.  Ionospheric detection of gravity waves induced by tsunamis , 2005 .

[15]  J. Klobuchar,et al.  Generation of kilometer scale irregularities during the midnight collapse at Arecibo , 1981 .

[16]  S. Ossakow.  Spread-F theories—a review , 1981 .

[17]  W. J. Burke,et al.  Ionospheric plasma bubble generated by Arecibo heater , 1998 .

[18]  T. Lane,et al.  Modelling the generation of gravity waves by a maritime continent thunderstorm , 2001 .

[19]  B. Basu.  Generalized Rayleigh‐Taylor instability in the presence of time‐dependent equilibrium , 1997 .

[20]  Harold A. B. Gardiner,et al.  MSX satellite observations of thunderstorm‐generated gravity waves in mid‐wave infrared images of the upper stratosphere , 1998 .

[21]  L. C. Gentile,et al.  DMSP observations of equatorial plasma bubbles in the topside ionosphere near solar maximum , 2001 .

[22]  Lawrence Weiskrantz,et al.  Discussions and conclusions , 1998 .

[23]  Hao YongQiang,et al.  Responses of the Ionosphere to the Great Sumatra Earthquake and Volcanic Eruption of Pinatubo , 2006 .

[24]  M. Larsen,et al.  Gravity wave initiation of equatorial spread F: A case study , 1981 .

[25]  F. S. Johnson,et al.  Occurrence of equatorial F region irregularities: Evidence for tropospheric seeding , 1998 .

[26]  Michael C. Kelley,et al.  Imaging the structure of a large‐scale TID using ISR and TEC data , 2004 .

[27]  Philippe Lognonné,et al.  Ionospheric remote sensing of the Denali Earthquake Rayleigh surface waves , 2003 .

[28]  Hiroo Kanamori,et al.  COMPUTATION OF SEISMOGRAMS AND ATMOSPHERIC OSCILLATIONS BY NORMAL-MODE SUMMATION FOR A SPHERICAL EARTH MODEL WITH REALISTIC ATMOSPHERE , 1998 .

[29]  E. Manzini,et al.  Middle Atmospheric Traveling Waves Forced by Latent and Convective Heating , 1993 .

[30]  Tsunamis and Earthquakes: What Physics Is Interesting? , 2005 .

[31]  Frederick J. Rich,et al.  Large-scale convection patterns observed by DMSP , 1994 .

[32]  S. Vadas,et al.  Influence of solar variability on gravity wave structure and dissipation in the thermosphere from tropospheric convection , 2006 .

[33]  T. Dunkerton,et al.  Generation of Inertia–Gravity Waves in a Simulated Life Cycle of Baroclinic Instability , 1995 .

[34]  J. Vincent Eccles,et al.  A simple model of low‐latitude electric fields , 1998 .

[35]  J. Testud,et al.  Medium scale gravity waves in the ionospheric F-region and their possible origin in weather disturbances , 1975 .

[36]  Eric Jeansou,et al.  Ground-based GPS imaging of ionospheric post-seismic signal , 2006 .

[37]  W. J. Burke,et al.  Augmentation of natural ionospheric plasma turbulence by HF heater waves , 1999 .

[38]  C. O. Hines,et al.  INTERNAL ATMOSPHERIC GRAVITY WAVES AT IONOSPHERIC HEIGHTS , 1960 .

[39]  Hélène Hébert,et al.  Three‐dimensional waveform modeling of ionospheric signature induced by the 2004 Sumatra tsunami , 2006 .

[40]  W. J. Burke,et al.  Polar observations of convection with northward interplanetary magnetic field at dayside high latitudes , 1998 .

[41]  W. J. Burke,et al.  Generation of large sheet‐like ionospheric plasma irregularities at Arecibo , 1998 .

[42]  Anthea J. Coster,et al.  Automated GPS processing for global total electron content data , 2006 .

[43]  Vasily Titov,et al.  The Global Reach of the 26 December 2004 Sumatra Tsunami , 2005, Science.

[44]  Mark Wilson.  Modeling the Sumatra–Andaman earthquake reveals a complex, nonuniform rupture , 2005 .

[45]  P. J. Sultan,et al.  Linear theory and modeling of the Rayleigh‐Taylor instability leading to the occurrence of equatorial spread F , 1996 .

[46]  Kaoru Sato,et al.  Gravity Waves Appearing in a High-Resolution GCM Simulation , 1999 .

[47]  F. S. Johnson,et al.  Gravity wave seeding of equatorial plasma bubbles , 1997 .

[48]  M. Nicolls,et al.  Strong evidence for gravity wave seeding of an ionospheric plasma instability , 2005 .

[49]  R. Walterscheid,et al.  A continuum of gravity waves in the Arecibo thermosphere? , 2003 .

[50]  Aditi Das,et al.  Ionospheric perturbations observed by the GPS following the December 26th, 2004 Sumatra-Andaman earthquake , 2006 .

[51]  M. J. Davis,et al.  Traveling ionospheric disturbances originating in the auroral oval during polar substorms , 1969 .

[52]  Raphaël F. Garcia,et al.  Tsunami detection in the ionosphere , 2005 .

[53]  P. Lognonné,et al.  Normal modes modelling of post‐seismic ionospheric oscillations , 2001 .

[54]  H. Booker,et al.  Scattering of radio waves by the F-region of the ionosphere , 1938 .