2007 Fiscal Year Final Research Report Summary
Precise measurement of the atmospheric transparency for the cosmic ray energy calibration in the TA experiment
| Project/Area Number |
18403004
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 海外学術 |
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| Research Field |
Particle/Nuclear/Cosmic ray/Astro physics
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| Research Institution | Kinki University |
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Principal Investigator |
CHIKAWA Michiyuki Kinki University, Physics, Professor (50179941)
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| Co-Investigator(Kenkyū-buntansha) |
HAYASHIDA Naoaki University of Tokyo, Institute for Cosmic Ray Research, Assistant (50114616)
OGIO Shouichi Osaka City University, Physics, lecturer (20242258)
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| Project Period (FY) |
2006 – 2007
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| Keywords | cosmic rays / atmospheric fluorescence / Transparency of atmosphere / LIDAR method |
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| Research Abstract |
1. There are many experiments to measure the atmospheric properties, especially its transparency, in the field of meteolology, planet science, earth science, environmental science, biological and so on. The purposes of their experiments are really manifold and there are many theoretical models to explain. The atmosphere is consist of molecules of some chemical components and various aerosol, and has very important role for the weather condition and the thermal balance due to circulation in the troposphere.
An atmospheric monitoring system has installed at Utah desert in the USA, to study the properties of atmosphere using a laser LIDAR(Light Detection And Ranging) system and an infra-red(IR) camera. Its original aim is to measure the atmospheric transparency for a cosmic rays experiment, the Telescope Array Experiment, which has many fluorescent light detectors. For this aim, the atmospheric extinction coefficient and the cloudiness should be determined precisely as possible, e.g. spati
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al resolution of less than 15m.
2. What have done are ;
(1) The LIDAR system consisits of a laser emitter and a light receiver with a photo multiplier tube(PMT) mounting on a steerable base. The laser emits pulse lights successively into the atmosphere and the receiver detects scattered faint lights by the PMT. To determine the atmospheric extinction coefficient, a large amount of data has been acquired using LIDAR system at the Utah desert commencing from July 2005. There are over 310,000 events data at the end of FY2007 and is analyzed by means of so-called the slope method and/or the Klett's method after due consideration of atmospheric pressure effect. A consistent result with a calculation of the Rayleigh scattering is obtained for the vertical extinction coefficient above an altitude of about ten kilometres in a calm weather. It is also found that the one-dimentional atmospheric density model is reasonable assumption within the accuracy of few percent uncertainty on a limitative condition in the Utah desert.
(2) The LIDAR for LR site is still continued an R&D and shall expect to install in FY2008.
(3) We can also suggests to distinguish the Rayleigh scattering (air molecular) component and the Mie(aerosol) scattering componet from the data analysis within several percents resolution comparing with a theoretical prediction.
Also we have installed an infra-red camera at BRM site in March 2008 to measure cloud and/or water vapour component in the atmosphere. Less
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Research Products
(19 results)
