Public Release of Observation Data of the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) aboard Japanese Experiment Module “KIBO” on the International Space Station

The Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) implemented Earth’s atmosphere observation mission with unprecedented high-precision, owing to the superconducting detector cooled down to 4K (-269 deg C). SMILES was developed under cooperation between National Institute of Information and Communications Technology (NICT) and Japan Aerospace Exploration Agency (JAXA), and it had been attached to the Japanese Experiment Module “KIBO” onboard the International Space Station.

JAXA and NICT have been carrying on improvement of retrieval of atmospheric minor constituents in order to demonstrate high performance of SMILES instrument and have been distributing level-2 observation data limited to the selected research groups among all applicants to the SMILES Research Announcement in August of 2009.

This time, we would like to release the SMILES observation data to the public, as we confirmed the high precision of these data. The data released to the public are the altitude distribution of 11 types of atmospheric minor constituents including ozone and chlorine compounds, retrieved from brightness temperature of 625-650 GHz electromagnetic emission measured by SMILES instrument. These data explain chemical phenomena of atmospheric minor constituents in stratosphere and lower mesosphere, therefore they contribute to the comprehensive analysis of Earth’s climate change including stratospheric ozone variation (such as “Ozone hole problem”) and global warming issues.

[SMILES website for data release]
http://smiles.isas.jaxa.jp/access/indexj.shtml

*	To whom wish to download these data, we request to register on this website. Please send e-mail towith description of your name, affiliation and objectives for utilizing those data (around 50 words). We will reply to your application with some information how to download the data.

This profile shows an observation sample over latitude 32 degree north and longitude 140 degree east. H-shaped horizontal lines mean errors of concentration at each altitude. (Short lines mean low errors, that is high precision.) A blue line (SMILES data) shows lower errors than a red dashed line (observation data near this point with the American earth observation satellite). Looking at distribution itself, the blue line shows mound-shaped distribution compared with the zigzag red line, so SMILES seems to capture the chemical process of atmosphere with higher precision.

This figure shows a sample of observation from over east coast of Canada to China via northern Europe (upper right panel). Remaining three panels show the vertical distribution of concentration of ozone, ClO and HCl respectively.

SMILES is an atmospheric observation sensor for measuring weak sub-millimeter wave emitted from atmospheric minor constituents with cryogenically-cooled superconducting detector. The superconducting detector can suppress its thermal noise to ultimate low levels, which improves its measurement performance. Compared with the existing spaceborne instruments without using superconducting detectors, SMILES revealed as one-digit higher performance than that of those instruments. As a result, SMILES carried out precise observation of minor constituents which were difficult to detect using previous instruments. SMILES was attached to the Exposed Facility of “KIBO” module in September 2009, and soon its operation started. SMILES acquired 6-month observation data of Earth’s atmosphere till its malfunction of the oscillator component inside the instrument in April 2010.