The Submillimeter-wave and Infrared Ice Cloud Experiment (SIRICE) concept would provide global measurements of ice water path (IWP - the vertically integrated mass of ice particles per unit area), and weighted mean mass particle diameter (D<sub>me</sub>). The SIRICE payload consists of two instruments, the Sub-millimeter/Millimeter (SM4) Radiometer, and the Infrared Cloud Ice Radiometer (IRCIR). IRCIR is a compact, low-cost, multi-spectral, wide field of view pushbroom infrared imaging radiometer. IRCIR will employ four IR sensor assemblies to produce 90° cross-track (contiguous along-track) coverage in three spectral bands with a spatial resolution of 0.6 km at nadir. Each IR sensor assembly consists of an uncooled microbolometer focal plane array (FPA), associated sensor core electronics, a stripe filter fixed at the FPA, and an IR lens assembly. A single scene mirror is used to provide two Earth view angles, as well as calibration views of space and the on-board calibration blackbody. The two Earth view angles will be used for stereo cloud height retrievals.
Space-based observations of tropospheric trace species have been identified as high-priority atmospheric science measurements to be included in Earth science missions of the 21st century. Critical to such measurements are tropospheric ozone (O<SUB>3</SUB>) concentrations, which have been increasing and will continue to do so as levels of the precursor gases (oxides of nitrogen, methane and other hydrocarbons) necessary for the photochemical production of tropospheric O<SUB>3</SUB> remain rising; such a global monitoring capability is crucial to enhance scientific understanding as well as to potentially lessen the ill-health impacts associated with exposure to elevated concentrations in the lower atmosphere. An instrument concept to enable such a measurement capability for tropospheric (and total) O<SUB>3</SUB> utilizing Fabry-Perot interferometry has been developed and reported in earlier work. It involves a double-etalon series configuration Fabry- Perot interferometer (FPI) along with an ultra-narrow bandpass filter to achieve single-order operation with an overall spectral resolution of approximately .068 cm<SUP>-1</SUP>, sampling a narrow spectral region within the strong 9.6 micrometer ozone infrared band from a nadir-viewing satellite configuration. Current research efforts are focusing on technology development and demonstration activities to address technology drivers and other design considerations associated with this measurement concept. Most importantly, we have developed a small-scale, modular, double-etalon prototype FPI for laboratory characterization and testing. This presentation will focus on advancements made pertaining to our laboratory prototype, specifically, toward the analysis and interpretation of measured solar absorption spectra. Topics will include processing of 'measured' spectra (i.e., spectral registration and drift correction) and simulation of 'true' spectra (i.e., atmospheric assumptions and instrument transfer function modeling), as well as subsequent comparisons and findings. Future developments will focus on incorporating other key elements into the prototype instrument, performing relevant laboratory and atmospheric testing, and developing methods for calibration. These activities along with concurrent scientific studies and atmospheric field testing will serve to demonstrate overall feasibility and provide technique validation for this instrumentation and may lead to a future space-based implementation.
To take advantage of the large luminosity-resolution product of the Fabry-Pérot interferometer used in tandem with modest-aperture telescopes, a Fabry-Pérot interferometer has been developed that is widely adaptable to a variety of extended source observations. The instrument is designed for adaptability across a range of optical and near-IR (NIR) spectral lines from 550 to 1100 nm, which are characterized by a wide range of velocity distributions of the emitting species. The system features a twin-étalon configuration to provide an extended free spectral range and to enhance contrast when observations include bright reflected solar or twilight backgrounds. Although the optical path and all the optical elements of the system are readily accessible, the instrument is ruggedized for transportability and extended remote field operation once it is optically configured. State-of-the-art, modularly adaptable, proven detectors (GaAs photomultipliers, large CCDs, and germanium integrating detectors) are featured to optimize instrument sensitivity. Recently, a series of NIR observations were made at the Millstone Hill Incoherent Scatter Radar Facility, Westford, Massachusetts, in a single-étalon mode.
To take advantage of the large luminosity-resolution product of the Fabry-Perot interferometer used in tandem with modest aperture telescopes, a Fabry-Perot interferometer has been developed that is widely adaptable to a variety of extended source observations. The instrument is designed for adaptability across a range of optical and near infrared spectral lines from 550 nm to 1,100 nm, which are characterized by a wide range of velocity distributions of the emitting species. The system features twin etalon configuration to provide extended free spectral range and to enhance contrast when observations include bright reflected solar or twilight backgrounds. Although the optical path and all optical elements of the system are readily accessible, the instrument is ruggedized for transportability and extended remote field operation once optically configured. State-of-the-art, but proven detectors (GaAs photomultipliers, large charge coupled devices, and Ge-Nitride integrating detectors) are featured to optimize instrument sensitivity, and are modularly adaptable.