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Comparison of ozone profiles between Superconducting Submillimeter‐Wave Limb‐Emission Sounder and worldwide ozonesonde measurements
Author(s) -
Imai Koji,
Fujiwara Masatomo,
Inai Yoichi,
Manago Naohiro,
Suzuki Makoto,
Sano Takuki,
Mitsuda Chihiro,
Naito Yoko,
Hasebe Fumio,
Koide Takashi,
Shiotani Masato
Publication year - 2013
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2013jd021094
Subject(s) - radiosonde , latitude , environmental science , ozone , submillimeter wave , atmospheric sciences , meteorology , physics , geology , geodesy , optics , millimeter
We compared ozone profiles measured by the Superconducting Submillimeter‐Wave Limb‐Emission Sounder (SMILES) with those taken at worldwide ozonesonde stations. To assess the quality of the SMILES version 2.3 ozone data for 16–30 km, 601 ozonesonde profiles were compared with the coincident SMILES ozone profiles. The agreement between SMILES and ozonesonde measurements was generally good within 5%–7% for 18–30 km at middle and high latitudes but degraded below 18 km. At low latitudes, however, the SMILES ozone data showed larger values (~6%–15% for 20–26 km) than those at middle and high latitudes. To explain this bias, we explored some possible issues in the ozonesonde measurement system. One possibility is due to a pressure bias in radiosonde measurements with a pressure sensor, but it would be within a few percent. We also examined an issue of the ozonesonde's response time. The response time was estimated from ozonesonde measurements with ascending and descending profiles showing clear difference, by using the time lag correction method to minimize the difference between them. Our estimation shows 28 s on average which is a similar value derived by prelaunch preparation. By applying this correction to the original profiles, we found a negative bias of the ascending ozonesonde measurement more than 7% at 20 km in the equatorial latitude where the vertical gradient of ozone is steep. The corrected ozonesonde profiles showed better agreement with the SMILES data. We suggest that the response time of ozonesondes could create a negative bias, particularly in the lower stratosphere at equatorial latitudes.