System design and examination of spaceborne microwave rain-scatterometer

The remote sensing of precipitation, especially rain by the spaceborne weather radar is an important subject which has not been realized. The system design and examination of the spaceborne weather radar which is called as the spaceborne microwave rain-scatterometer are performed by considering user's requirements to observe rain, the restrictions derived from the interface with satellite and the state of the art and the possibility of spaceborne microwave technology. Characteristic parameters for spaceborne microwave rain-scatterometer are determined based on the user's requirements for the system. Functions and performances of each subsystem (antenna, transmitters, receivers and data transmission processor) with the detailed block diagram of the total system of spaceborne microwave rain-scatterometer are shown. All of the critical items of hardware in the development of spaceborne microwave rain-scatterometer are also discussed.     

Feedback Transmission of Binary Data with Automaton Receiver

Feedback transmission of binary data over a discrete-time additive Gaussian white noise channel is considered. The effect of some specific finite memory structure at the receiver is investigated. The whole communication scheme is the discrete analog of the one previously analyzed by Khas'minskii. The resulting average transmission time is increased by only about 20 percent of the theoretical limit in the low signal-to-noise ratio region. Numerical results are also shown.     

An observation of snow melting process from remotely sensed data

Observations of satellite images have shown that the snow melting in mountainous area proceeds more repidly in the east-facing slope of the valley than in the west-facing one. The energy for melting snow consists of the total from the atmosphere and from the solar rays. The diurnal variation of the solar energy into the snow in the east-facing slope differs from that in the west-facing slope. This causes the heighest value of the instantaneous energy for melting snow to occur in the west-facing surface. As one of the reasons for the above tendency, the difference of the heighest value to melt snow may be taken into account.     

Physics of ion acceleration in the solar flare on 2005 September 7 determines γ-ray and neutron production

Relativistic neutrons were observed by the neutron monitors at Mt. Chacaltaya and Mexico City and by the solar neutron telescopes at Chacaltaya and Mt. Sierra Negra in association with an X17.0 flare on 2005 September 7. The neutron signal continued for more than 20 min with high statistical significance. Intense emissions of γ-rays were also registered by INTEGRAL, and during the decay phase by RHESSI. We analyzed these data using the solar-flare magnetic-loop transport and interaction model of Hua et al. [Hua, X.-M., Kozlovsky, B., Lingenfelter, R.E. et al. Angular and energy-dependent neutron emission from solar flare magnetic loops, Astrophys. J. Suppl. Ser. 140, 563–579, 2002], and found that the model could successfully fit the data with intermediate values of loop magnetic convergence and pitch-angle scattering parameters. These results indicate that solar neutrons were produced at the same time as the γ-ray line emission and that ions were continuously accelerated at the emission site.     

Search for primordial antiparticles with BESS

The Balloon-borne Experiment with a Superconducting Spectrometer (BESS) has been carried out to search for primordial antiparticles in cosmic rays. In ten flights from 1993 to 2004, it measured the cosmic-ray antiproton spectrum in the energy range 0.1–4.2 GeV at various solar activity conditions. It also searched for antideuterons and antihelium nuclei, and it made precise measurement of cosmic-ray particle spectra. The BESS program has been extended to long duration balloon (LDB) flights in Antarctica (BESS-Polar) with the goal of achieving unprecedented sensitivity in the search for primordial antiparticles. This report describes recent results from BESS and progress of the BESS-Polar program.