A5045877224- Planetary Science and Exploration
- Astro and Planetary Science
- Climate variability and models
- Meteorological Phenomena and Simulations
- Solar and Space Plasma Dynamics
- Oceanographic and Atmospheric Processes
- Tropical and Extratropical Cyclones Research
- Geology and Paleoclimatology Research
- High Temperature Alloys and Creep
- Microstructure and Mechanical Properties of Steels
- Atmospheric aerosols and clouds
- Geophysics and Gravity Measurements
- Geomagnetism and Paleomagnetism Studies
- Space Exploration and Technology
- Metal Alloys Wear and Properties
- Superconducting Materials and Applications
- Atmospheric and Environmental Gas Dynamics
- Metallurgy and Material Forming
- Atmospheric chemistry and aerosols
- Coagulation and Flocculation Studies
- Spaceflight effects on biology
- Superconductivity in MgB2 and Alloys
- Particle accelerators and beam dynamics
- Space Science and Extraterrestrial Life
- Solidification and crystal growth phenomena
International Superconductivity Technology Center
2023-2025
Kyushu University
2015-2024
Futaba (Japan)
2020-2023
Rikkyo University
2013
Wakayama University
2001-2006
Tokyo Metropolitan University
1977-2003
Fuji Machine (Japan)
2000
Yokohama National University
1995-1999
Nagoya University
1977-1998
Sumitomo Heavy Industries (Japan)
1990
AKATSUKI is the Japanese Venus Climate Orbiter that was designed to investigate climate system of Venus. The orbiter launched on May 21, 2010, and it reached December 7, 2010. Thrust applied by orbital maneuver engine in an attempt put into a westward equatorial orbit around with 30-h period. However, this operation failed because malfunction propulsion system. After failure, spacecraft orbited Sun for 5 years. On 2015, once again approached insertion successful, whereby apoapsis ~440,000 km...
Formation and maintenance of the fully developed superrotation in Venus atmosphere are investigated by using a Center for Climate System Research/National Institute Environmental Study (CCSR/NIES) Venus-like atmospheric general circulation model. Under condition that zonally uniform solar heating is used, meridional dominated single cell whole atmosphere, with velocities faster than 100 m s–1 formed near 60-km altitude. The effectively pumps up angular momentum from lower to middle...
The Akatsuki spacecraft of Japan was launched on May 21, 2010. planned to enter a Venus-encircling near-equatorial orbit in December 7, 2010; however, the Venus insertion maneuver has failed, and at present is orbiting Sun. There possibility conducting an again several years later. main goal mission understand Venusian atmospheric dynamics cloud physics, with explorations ground surface interplanetary dust also being themes. angular motion roughly synchronized zonal flow near base for 20...
Fully developed superrotation—60 times faster than the planetary rotation (243 days)—is simulated using a Venus-like atmospheric general circulation model (AGCM). The angular momentum of superrotation is pumped up by meridional with help waves, which accelerate equatorial zonal flow. waves generated solar heating and shear instability play crucial role in dynamics Venusian superrotation. Vertical horizontal transports thermal tides maintain middle atmosphere, while equatorward eddy flux due...
A 4‐day superrotation 60‐times faster than the planetary rotation (243 days) is observed in Venus' atmosphere. Although it has been difficult to reproduce extraordinary phenomenon GCMs, reproduced by meridional circulation and planetary‐scale waves with phase velocities slower 50 m s −1 our improved GCM. Thermally induced produce equatorward momentum fluxes middle atmosphere, while pattern of two different gravity Rossby same frequency found flux lower These processes play crucial roles...
The role of the extratropical ocean in climate remains unclear due to complexities air‐sea interaction processes. We have found robust evidence for Tsushima Warm Current (TWC) preceding western Pacific (WP) teleconnection pattern by conducting an analysis over past 30 years. WP index winter sharply succeeds volume transport TWC autumn, but rather smoothly connects with El Niño indices, indicating a considerable current system. Correlation patterns seasonal precipitation Japanese Islands are...
Superrotation of more than 100 m s −1 is formed at the cloud top (65–70 km) in a T21 Venus‐like atmospheric general circulation model (Venus‐like AGCM) driven by zonal‐mean thermal forcing. This maintained Gierasch mechanism, which meridional efficiently pumps up angular momentum and various waves produce equatorward eddy fluxes. In addition to above fast equatorial with wide frequency range (including famous 4‐day wave) enhance cloud‐top superrotation, since downward flux vertically...
It is difficult to estimate high‐resolution sea surface temperature (SST) distributions in coastal areas under cloudy and rainy weather conditions. This study makes use of dynamical estimates SST produced by combining satellite measurements into an eddy‐resolving ocean general circulation model (OGCM). The reanalyzed provides improved boundary condition for mesoscale atmospheric simulations. We examined a developing cyclone passing over the Japan Sea comparative experiments undertaken using...
The dynamics of Venus' lower‐atmospheric superrotation remain an open issue. In the present study, we investigate sensitivity to diabatic heating rate below cloud layer using a simplified GCM. A fully developed fails develop in lower atmosphere under condition with fairly low layer, as is thought be realistic. Additional radiative forcing and/or eddy momentum source should considered produce superrotation. controls formation multiple states (slow, fast, and extremely fast superrotations)....
Abstract Venusian cloud structure and variation are strongly linked to atmospheric dynamics. Past near‐infrared measurements have found such as zonal‐wavenumber‐1 marking discontinuity. However, their formation mechanism is still not well understood. To investigate the its variation, we developed a Venus GCM incorporating condensation, evaporation, sedimentation, simple chemistry represent H 2 SO 4 cycle. The takes into account particles with radii of 0.3, 1.0, 1.26, 3.13 μm (Modes 1, 2, 2',...
Solar-locked and geographical atmospheric structures of daily averaged wind temperature on Venus were investigated using an general circulation model with Venusian topography a two-stream radiative code compared fields obtained from the Akatsuki ultraviolet imager. The horizontal simulated around subsolar region are similar to observed ones at cloud top. Mid-latitude jets ∼120 m s–1 equatorial fast flow ∼90 formed A poleward >8 is above layer, where solar heating strong. Around top, ∼1...
The Venus 4-day circulation, with wind speeds 60 times greater than the surface rotation, is located at top of cloud layer (65–70 km) in middle atmosphere planet. This dramatic phenomenon related to combination two processes, meridional circulation induced by solar heating and its associated poleward momentum transport, additional from a wave originating equatorial lower atmosphere. Numerical simulations are conducted for cases forcing boundary If no forced, significant zonal-mean appears...
The present study examines the influence of an assimilation SST product on simulated monthly precipitation. high-resolution structures located close to oceanic front and coastal areas are important in regional atmospheric simulations over semienclosed marginal seas such as Japan Sea. Two conducted using interpolation products (experiments R N, respectively), for January 2005. surface heat fluxes PBL height experiment lower than those N cold tongue. A decrease 4 K leads decreases 120 W m −2...
[1] The surface conditions of a small semi-enclosed ocean (the Japan Sea), largely controlled by the volume transport warm current, influence monthly mean atmospheric circulation over northwestern Pacific via active cyclogenesis. new dynamical processes induced Sea are proposed in this letter. When temperature is lowered regional model, potential vorticity increased Japanese Islands, and Okhotsk Low intensified at 500-hPa level. In case an amplified Low, cyclonic flow transports cold air...
Recent studies have discovered an intriguing nonstationary relationship between El Ninõ-Southern Oscillation (ENSO) and the Western Pacific (WP) teleconnection pattern, one of most prominent winter atmospheric circulation patterns in North Pacific, with a regime-dependent interdecadal modulation significant insignificant correlations. However, physical process underlying observed ENSO-WP is puzzle remains to be elucidated, which also essential for clarifying still-debated nontrivial issue on...
Abstract Sea surface temperature (SST) assimilated using an ocean circulation model is used for the atmospheric simulation of a cold‐air outbreak over Japan Sea. The upward surface‐turbulent heat fluxes are significantly influenced by high‐resolution SST structure resulting from mesoscale oceanic eddies. A strong deceleration due to local convective activity arises in coastal area when data, good agreement with observations; however, this feature not observed interpolated SST. In general,...
Abstract The significance of twin extratropical cyclones (in contrast to tropical cyclones) has not yet been fully recognized in weather forecasting and analysis heavy precipitation. This study investigated successive sets over the Yellow East China Seas (YECS) Japan Sea South Coast areas Japanese Islands (JSSC) on 9–10 October 2001. Although these were strong, they led precipitation Japan. southern low YECS cyclones, which accompanied a moist tongue, rapidly merged with northern cold low,...
Equatorial Kelvin waves, which have been observed in planetary fluids, produce superrotation and climatological variability. Although the meridional flow component is zero on Earth's beta-plane absence of background basic flow, it cannot be neglected spheres some fluids when Lamb parameter small. For a vertically propagating Kelvin-like wave wind shear, flows equatorward heat transport, i.e., downward Eliassen-Palm flux. The vertical momentum transport caused by flux has theoretical upper...
On Venus, the upper haze layer (70–90 km) is observed above cloud (48–70 km). An aerosol transport model using a two‐moment microphysical parameterization for and developed applied to wide height range of 24–94 km. The latitudinal dependence SO 2 oxidation mainly leads equator‐pole contrast mass loading, meridional circulation weakens loading through poleward transport. number concentration enhanced by in middle atmosphere. due should be considered as an important process formation Venus structure.
Parametric experiments of superrotation on slowly rotating planets, such as Venus, were conducted. The oblique angle the planetary rotation axis is one most important parameters in dynamics superrotation. New relationships are found for maximum mean zonal flow, meridional and equator‐pole temperature difference. For low obliquity, dynamic state alternates between weak strong superrotations with a period about 10000 days phase space, small fluctuations 1000 also seen. Fully‐developed...
Short-period responses of moisture and precipitation to sea surface temperature (SST) are investigated in model simulations for the case heavy Tsushima Strait on 26 July 2020, where both atmospheric oceanic fronts were established SST was much lower than climatological normal (30-year average late July) vicinity strait. Compared with experiments using SST, latent heat flux water vapor (higher) cooler (warmer southern East China Sea) control experiment. The area-mean is lowered by reduced...