K. Shibasaki

Submillimeter Limb-emission Sounder JEM/SMILES aboard the Space Station

A submillimeter limb-emission sounder, that is to be aboard the Japanese Experiment Module (JEM, dubbed as KIBO) at the International Space Station, has been designed. This payload, Superconducting Submillimeter-wave Limb-emission Sounder (SMILES), is aimed at global mappings of stratospheric trace gases by means of the most sensitive submillimeter receiver ever operated in space. Such sensitivity is ascribed to a Superconductor-Insulator- Superconductor (SIS) mixer, which is operated at 4.5 K in a dedicated cryostat combined with a mechanical cooler. SMILES will observe ozone-depletion-related molecules such as ClO, Hcl, HO2, HNO3, BrO and O3 in the frequency bands at 624.32-626.32 GHz and 649.12-650.32 GHz. A scanning antenna will cover tangent altitudes from 10 to 60 km in every 53 seconds, while tracing the latitudes form 38 S to 65 N along its orbit. This global coverage makes SMILES a useful tool of observing the low- and mid- latitudinal areas as well as the Arctic peripheral region. The molecular emissions will be detected by two units of acousto-optic spectrometers (AOS), each of which has coverage of 1.2 GHz with a resolution of 1.8 MHz. This high-resolution spectroscopy will allow us to detect weak emission lines attributing to less-abundant species.

Overview of GCOM-A1 science program

The Ozone Dynamics Ultraviolet Spectrometer (ODUS) is a satellite-borne, nadir-looking ultraviolet spectrometer for measuring total ozone amount. It will be launched in 2005 onboard Japanese earth observation satellite GCOM-A1 (GCOM: Global Change Observation Mission) satellite, which was formerly called Advanced Earth Observation Satellite-3A, ADEOS-3A. The ODUS instrument measures continuous spectrum from 306 to 420 nm with 0.5 nm spectral resolution and 20 km spatial resolution, using an Ebert-type specyrograph and a one-dimensional silicon array detector, which will improve the accuracy of the retrieved total ozone amount. This paper presents an overview of the GCOM-A1 and ODUS instrument, the summary of the evaluation results of the laboratory models.

Ozone dynamics ultraviolet spectrometer (ODUS)

The Ozone Dynamics Ultraviolet Spectrometer (ODUS) is a satellite-borne, nadir-looking ultraviolet spectrometer for measuring total ozone amount. It will be launched in 2005 onboard Japanese earth observation satellite GCOM-A1. The ODUS instrument measures continuous spectrum from 306 to 420 nm with 0.5 nm spectral resolution and 20 km spatial resolution, using an Ebert-type polychromator and a one-dimensional silicon CMOS array detector, which will improve the accuracy of the retrieved total ozone amount. We have completed the conceptual design of system, and manufactured and tested the laboratory model of the detector and the optical assembly. We have succeeded in developing a detector with sufficient sensitivity and a polychromator with little stray light. We have also confirmed the optical performance and evaluated the detailed wavelength structure of the instrument function. This paper presents an overview of the ODUS instrument, the summary of the evaluation results of the laboratory models.

Ozone mapping and expected products by ODUS

The Ozone Dynamics Ultraviolet Spectrometer (ODUS) will be on board the GCOM (Global Change Observation Mission)-A1 satellite. The main objectives of the ODUS mission are global mapping of total ozone field, monitoring of volcanic sulfur dioxide (SO/sub 2/), surface UV-B, and surface albedo. The total ozone will be derived in high accuracy of about 2% with a spatial resolution of 20 km /spl times/20 km at nadir view. By combining data obtained by ODUS and other instruments (SOFIS and SWIFT) on board GCOM-A1, the dynamical features of stratosphere will be revealed using ozone as a tracer. The tropospheric ozone field will also be derived. Spectroscopic measurement of solar scattered UV from the Earths atmosphere by ODUS also makes it possible to derive SO/sub 2/ and NO/sub 2/ over polluted atmospheric conditions. Other minor constituents such as BrO, OClO, and HCHO will also be measured. Information on aerosol amount and their types over land area are also research targets of the ODUS instrument. As for the system design of ODUS, investigations are extensively made from many aspects to construct a light and low power consumption sensor with high performance for measuring the UV spectra. The algorithm development is also important and started.

Polar thermosphere-stratosphere photochemical coupling experiment: Two rocket measurements in polar winter at 69°N

Two rocket experiments were carried out just before and after the polar night at Andoya (69°N), Norway to investigate transport of nitric oxide produced by auroral processes into the middle atmosphere and its influence on the ozone chemistry. Nitric oxide densities of (2−5) × 108 cm−3 found in the 70–90 km region are one to two orders of magnitude larger than those at middle latitudes. The measured density profiles appear to agree semi-quantitatively with model simulations which includes auroral processes. The influence on ozone densities in the 70–90 km region due to such enhanced nitric oxide abundance is found to be still insignificant as compared to that due to transport in the middle of February, one month after the end of polar night and one month before the spring equinox. The larger ozone densities found in February (in spite of longer sunlit duration) than in November in the 40–60 km region again support predominance of transport over photochemical destruction.

Sensitivity study for mapping the sulfur dioxide distributions with Ozone and Pollution measuring Ultraviolet Spectrometer (OPUS)

NASDA has been conducting an extended phase-A study on the Ozone and Pollution measuring Ultraviolet Spectrometer (OPUS), which is a nadir-looking, cross-track scanning ultraviolet spectrograph. OPUS was formerly named Ozone Dynamics Ultraviolet Spectrometer (ODUS). OPUS measures the backscattered solar radiation for the region between 306 and 420 nm with sampling step of 0.5 nm. It observes distributions of atmospheric ozone, sulfur dioxide (SO/sub 2/) and other parameters including aerosols. In this paper, (1) a feasibility of the retrieval of total column SO/sub 2/ is examined, and (2) a preliminary result on SO/sub 2/ measurement using airborne spectrograph is demonstrated.

GCOM-A1 program I. - program overview

The Ozone and Pollution measuring Ultraviolet Spectrometer (OPUS) is a satellite-borne, nadir-looking ultraviolet spectrometer for measuring total column ozone, SO/sub 2/, aerosols, NO/sub 2/, HCHO, BrO, and OClO. It will be a NASDAs core instrument of GCOM-A1 (GCOM: Global Change Observation Mission) satellite to be launched in 2007. The GCOM program is designed to determine the climate trends. The GCOM-A1 will carry the SOFIS (Solar-occultation FTS for Inclined-orbit Satellite, developed by Environment Agency of Japan), and SWIFT, which measures stratospheric wind, provided by ESA/CSA.

Instrument design of Ozone and Pollution measuring Ultraviolet Spectrometer (OPUS)

OPUS is a nadir-looking, cross-track scanning ultraviolet spectrograph, which will be boarded on NASDAs GCOM-A1 satellite (one of the first generation satellites of Global Change Observation Mission), which is proposed to be launched in the year 2007. OPUS was formerly named Ozone Dynamics Ultraviolet Spectrometer (ODUS). Recently, we have come to place importance on observation of polluted atmospheric condition as well as continuous monitoring of ozone from NASAs Total Ozone Mapping Spectrometer (TOMS) series. Consequently, we have started to study about modification of instrument specifications. Currently, OPUS takes over the specification of ODUS as it is, but according to the result of the study, OPUS might be equipped with some new features. In this paper, the latest outcomes of the study are presented.

GCOM-A1 science plan [Global Change Observation Mission]

GCOM-A1 is one of the satellite programs as follow-on of ADEOS and ADEOS-II. GCOM-A1 is under planning, which is targeting for the launch in 2007 (January-March). GCOM (Global Change Observation Mission) is a Japans new concept for systematic and long-term observation global environment and climate system from space. The mission concept of GCOM covers 15 years starting from ADEOS-II (February 2002 to 2007), GCOM-A1 and -B1 (2007-2012), and GCOM-A2 and -B2 (2012-17). Within this mission period, key geophysical parameters necessary to document and understand global changes and climate variability will be measured continuously, but it does not mean the same instruments will be deployed over 10 or 15 years. GCOM-A1 will be a satellite dedicated to measure parameters related to atmospheric chemistry and dynamics. It will carry three instruments, ODUS (Ozone Dynamics Ultraviolet Spectrometer) by NASDA, SOFIS (Solar Occultation FTS for Inclined orbit Satellite) by the Ministry of Environment of Japan, and SWIFT (Stratospheric Wind Interferometer For Transport studies) by ESA and CSA. ODUS is a satellite-borne, nadir-looking ultraviolet spectrometer for measuring total column ozone, SO/sub 2/, aerosols, NO/sub 2/, HCHO, BrO, and OClO. It will be NASDAs core instrument for GCOM-A1. SOFIS is a successor of ADEOS/ILAS and ADEOS-II/ILAS-II by using the solar occultation technique in the infrared region. SWIFT is a successor of UARS/WINDII but using the 9 /spl mu/m ozone emission line to measure the stratospheric winds (<5 m/sec from 20 to 45 km). The GCOM-A1 satellite will have a 650 km and 65 to 70 degree inclination orbit to enable good global coverage for SOFIS.

Overview of GCOM-A1 satellite program

The Ozone Dynamics Ultraviolet Spectrometer (ODUS) is a satellite-borne, nadir-looking ultraviolet spectrometer for measuring total column ozone, SO/sub 2/, aerosols, NO/sub 2/, HCHO, BrO, and OClO. It will be a NASDAs core instrument of GCOM-A1 (GCOM: Global Change Observation Mission) satellite to be launched in February 2006. The GCOM program is designed to determine the climate trends. The GCOM-A1 will carry the SOFIS (Solar-occultation FTS for Inclined-orbit Satellite, developed by Environment Agency of Japan), and other instruments to be provided by foreign space agencies.