Activity Report of Commission G report         November 1,2002/11/1

 

                                                     K.-I.Oyama and T.Maruyama

 

1. Sounding rocket experiment

SEEK-2 (Sporadic-E Experiment over Kyushu 2) is a project to observe sporadic-E layers and E-region ionospheric irregularities with two sounding rockets and many ground-based instruments in Japan.  Institute of Space and Aeronautical Sciences (ISAS), Kyoto University, Nagoya University, Tohoku University, University of Tokyo, Tokai University, and Communications Research Laboratory participate in SEEK-2.  From USA, Clemson University, University of Texas (USA), NASA, and SRI International, from Taiwan, National Central University join the project.  The experiment was successfully conducted in August 2002.  The sounding rockets S-310-31 and S-310-32 were launched from Kagoshima Space Center (KSC), ISAS on 23:24 JST and 23:39 JST on August 3, 2002, respectively.  Radio Science Center for Space and Atmosphere (RASC), Kyoto University conducted 31.57MHz-radar measurement from Tanegashima Space Center (TNSC), National Space Development Agency (NASDA), and could find very good launch timing when intense quasi-periodic structures appeared in the E-region irregularities.  All instruments on both rockets, and all ground observations were successful.

 

2. Ground  based observations

The MU radar continues ionospheric IS observations according to the international observation schedule of Incoherent Scatter Coordinate Observation Day.  We study behavior of mid-latitude ionosphere based on the MU radar data.  Lower Thermosphere Profiler Radar (LTPR) is continuously operated in Shigaraki MU Observatory.  In addition to the E-region irregularity echoes, LTPR now simultaneously observes meteor echoes to measure neutral winds in 80-100km altitudes.  Results from these observations are valuable to reveal complicated dynamics of the ionosphere-therosphere coupling.

  The Solar-Terrestrial Environment Laboratory, Nagoya University have conducted all-sky airglow measurement at Tanegashima, Kagoshima (southern edge of Japan) during the SEEK2 rocket campaign.  Several interesting features were observed.  They are, gravity waves associated with E-region illegularities, intense medium-scale traveling ionospheric disturbances, and artificial aurora due to a chemical release from the rocket. 

   Radio Science Center for Space and Atmosphere (RASC), Kyoto University established Equatorial Atmosphere Radar (EAR) in 2001 over the geographic equator in West Sumatra, Indonesia (100.32E, 0.20S).  It is a giant 47MHz atmospheric radar with an active phased-array antenna system with a diameter of 110m.  EAR can steer its antenna beam from pulse to pulse basis, and survey three-dimensional structure of the atmosphere.  Since the geomagnetic latitude of EAR is about 10 degrees South, EAR is suitable to study low-latitude ionosphere in the southern hemisphere.  EAR observations of echoes from Spread-F and E-region irregularity are conducted in a campaign basis.  Eastward motion of Spread-F echoes are often observed.  In 2001-2007 Scientific Research of Priority Areas "Coupling Processes in the Equatorial Atmosphere (CPEA)" is conducted to enhance atmospheric dynamics around the EAR site.  According to the project airglow imagers will soon be installed in the EAR site by Solar-Terrestrial Environment Laboratory, Nagoya University, which add more capability of studying low-latitude ionosphere.

    Rapid ionosonde observations were made each minute during the Perseid meteor shower event from August 10 to 15 at four stations, Wakkanai,Kokubunji/Tokyo, Yamagawa, and Ogimi/Okinawa. Also, in accord with the SEEK-2 rocket and radar campaign for sporadic E

study, ionograms were obtained each minute at Yamagawa from July 26 toAugust 31.

   GPS data which have been acquired by Geophysial Survey Institute of Japan are being analysed at Kyoto University,Nagoya University and the Institute of Space and Astronautical Science on the different topics.

3.Workshop and Symposium

3.1 34^th COSPAR Scientific Assembly  was held 11-20 October 2002 in Houston Texas.

3.2 German National URSI meeting,Sep30-Oct2,2003 at Kleinheubach Tagung Germany.

Special one day session is planned  in honor of  Professor Karl Rawer's 90^th Birthday.

Title is " Three decades of　International Reference Ionosphere"

3.3 IRI Workshop 2003

The IRI WG accepted the　invitation　by A.Poole and L.-A.McKinnel and will hold  its 2003 workshop at the Rhodes University in Grahamstown,South Africa,　in the week of October 6-10,2003.

 

4. Publications and Symposium presentations

4.1 IRI News September Issue was distributed to the IRI scientists in the world. Maqnuscripts for the December issue  is now being collected.

 

1. Maeda.S..Nozawa, M. Sugino, H. Fujiwara, M. Suzuki, Ion and neutral temperature distributions in the dayside E-region observed by  the EISCAT Tromsoe and Svalbard radars,Annales Geophysicae,.20, 1415, 2002.

2. Oyama,k.-I.,P.Marinov,and I.Kutiev,Model of electron temperature variations at 600km in low latitude based on Hinotori data,COSPAR ,Houston,Oct,2002

3.Kutiev,I.,K.-I.Oyama,and T.Abe,Plasmasphere electron temperature model based on Akebono data,COSPAR,Houston,Oct.2002.

4.Pavlov,A.V.,T.Abe,and K.-I.Oyama,Anomalous electron thermal conductivity of the plasmasphere and topside ionosphere obtained from model/data comparison,COSPAR ,Houston,2002

5 Navatov,A.S.,K.-I.Oyama,N.A.Savich,and K.Noguchi,Application of  SELENE radio communication system to occultation measurement,COSPAR Houston,2002

6. Rawer K.,D.Bilitza,B.Reinish,L.Triskova,and K.-I.Oyama,The URSI/COSPAR standard for the ionosphere:International Reference Ionosphere,COSPAR,Houston,2002.