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ILAS-2 Image


Improved Limb Atmospheric Spectrometer-II (ILAS-II) developed by the Environment Agency of Japan (The present Ministry of Environment) is a sensor to monitor the high-latitude stratospheric ozone. The objectives of ILAS-II are to monitor and study changes in the stratosphere which are triggered by emissions of chlorofluorocarbons (CFC), and to evaluate the effectiveness of world-wide emission controls of CFCs. ILAS-II is a spectrometer which observes the atmospheric limb absorption spectrum from the upper troposphere to the stratosphere using sunlight as a light source (solar occultation technique).

The spectrometer covers the infrared region (2-13ƒÊm) and the near visible region (753 to 784nm). ILAS-II was designed to improve observation accuracy and cover wider spectral ranges than ILAS (aboard ADEOS planned for 1996 launch by NASDA) which was based on LAS aboard EXOS-C (Ohzora, ISAS, 1984). ILAS's observations are focused in the high latitude regions because of the geometrical relation of the solar occultation events with the sun-synchronous orbit. From these spectral observations, ILAS-II can measure the vertical profiles of species related to ozone hole phenomena:ozone (O3), nitrogen dioxide (NO2), aerosols, water vapor (H2O), CFC11, methane (CH4), nitrous oxide (N2O), chlorine nitrate (CIO NO2), temperature, and pressure.


Spectral Coverage CH:1 : 6.21 - 11.76mm(1610 - 850cm - 1)
CH:2 : 3.0 - 5.7mm(3333 - 1754cm - 1)
CH:3 : 12.78 - 12.85mm(782 - 778cm - 1)
CH:4 : 753 - 784nm
Spatial Coverage(Height) 10 - 60km
Vertical Resolution 1km
Observation Region N57 - 73deg / S64 - 90deg
Spectrometer CH:1 : Grating Spectrometer
CH:2 : Grating Spectrometer
CH:3 : Grating Spectrometer
CH:4 : Concave Grating Spectrometer
Observation Parameters O3,HNO3,NO2,N2O,CH4,H2O
CIONO2,Aerosols,Pressure and Temperature,CO2

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