The polar ozone and aerosol measurement experiment (POAM II) was launched on the SPOT 3 satellite on 25 September 1993. POAM II is designed to measure the vertical profiles of the polar ozone, aerosols, water vapor, nitrogen dioxide, atmospheric density and temperature in the stratosphere and upper troposphere. It makes solar occultation measurements in nine channels defined by narrow-band filters. The field of view is 0.01 by 1.2 degrees, with an instantaneous vertical resolution of 0.6 km at the tangent point in the earth's atmosphere. The SPOT 3 satellite is in a 98.7-degree inclined sun-synchronous orbit at an altitude of 833 km. From the measured transmissions, it is possible to determine the density profiles of aerosols, O3, H2O, and NO2. Using the assumption of uniformly mixed oxygen, we are also able to determine the temperature. We present details of the POAM II instrument design, including the optical configuration, electronics and measurement accuracy. We also present preliminary results from the occultation measurements made to date.
|