Session
Technical Session VII: Advanced Technologies II
Abstract
The Earth’s lower thermosphere is an important interface region between the neutral atmosphere and the “space weather” environment. The NSF-sponsored Optical Profiling of the Atmospheric Limb (OPAL) mission is designed to map global thermospheric temperature variability at mid- and low-latitudes over the critical “thermospheric gap” region (~100-140 km altitude) where prior data are sparse. OPAL will profile the thermosphere temperature from 90 to 140 km altitude by observing the daytime O2 A-band emission. OPAL measures the thermosphere neutral temperature by spectroscopic analysis of molecular oxygen Aband emission (758 – 768 nm). This paper presents the OPAL mission science, instrument design, and measurement capabilities. OPAL is expected to launch in late 2016 with a mission duration > 9 months. The OPAL instrument is a grating-based imaging spectrometer with refractive optics and a high-efficiency volume holographic grating (VHG). The scene is sampled by 7 parallel slits that form non-overlapping spectral profiles at the focal plane with resolution of 0.5 nm (spectral), 1.5 km (limb profiling), and 60 km (horizontal sampling). A CCD camera at the instrument focal plane delivers low noise and high sensitivity. The instrument is designed to strongly reject stray light from daylight regions of the earth.
Presentation
Hyperspectral Limb Scanner for the OPAL Mission
The Earth’s lower thermosphere is an important interface region between the neutral atmosphere and the “space weather” environment. The NSF-sponsored Optical Profiling of the Atmospheric Limb (OPAL) mission is designed to map global thermospheric temperature variability at mid- and low-latitudes over the critical “thermospheric gap” region (~100-140 km altitude) where prior data are sparse. OPAL will profile the thermosphere temperature from 90 to 140 km altitude by observing the daytime O2 A-band emission. OPAL measures the thermosphere neutral temperature by spectroscopic analysis of molecular oxygen Aband emission (758 – 768 nm). This paper presents the OPAL mission science, instrument design, and measurement capabilities. OPAL is expected to launch in late 2016 with a mission duration > 9 months. The OPAL instrument is a grating-based imaging spectrometer with refractive optics and a high-efficiency volume holographic grating (VHG). The scene is sampled by 7 parallel slits that form non-overlapping spectral profiles at the focal plane with resolution of 0.5 nm (spectral), 1.5 km (limb profiling), and 60 km (horizontal sampling). A CCD camera at the instrument focal plane delivers low noise and high sensitivity. The instrument is designed to strongly reject stray light from daylight regions of the earth.
