Diurnal variations of stratospheric / mesospheric trace species , ClO , BrO , and HO 2 derived from 4 K cooled submm limb sounder ISS / JEM / SMILES
Diurnal variations of stratospheric / mesospheric trace species , ClO , BrO , and HO 2 derived from 4 K cooled submm limb sounder ISS / JEM / SMILES
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来自4K冷却亚毫米临边探测器ISS / JEM / SMILES的平流层/中层微量物质、ClO、BrO和HO 2 的日变化
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发表时间：
2011
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通讯作者：
M. Shiotani
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作者：
Makoto Suzuki;C. Mitsuda;C. Takahashi;N. Manago;Y. Iwata;T. Sano;K. Kikuchi;S. Mizobuchi;T. Nishibori;K. Imai;H. Hayashi;E. Nishimoto;Y. Naito;M. Shiotani
超导亚毫米波LimbEmission探测器（SMILES） （Kikuchi et al., 2010）是国际空间站（ISS）日本实验舱/暴露设施（JEM/EF）上的早期科学项目之一。SMILES由JAXA和NICT联合开发。smile采用4 K冷却的超导体-绝缘体-超导体（SIS）结装置测量625650 GHz频率区域的地球临边，结果Tsys ~ 400K， NEDT ~ 0.4 K，即比以前在mm/亚mm波长区域的临边大气测量(如AURA/MLS （Waters et al., 2006）和ODIN/SMR（Frisk et al., 2003）高10倍。smile可以测量与O3层化学相关的几种关键物质；O3 (O3， OOO， OOO， OOO， OOO), HCl (HCl和HCl), ClO, HO2, HOCl， BrO和CH3CN。在350 ~ 400 km和52°倾斜的ISS轨道上，smile的岁差周期为88 ~ 90天，这意味着smile可以在45天的观测时间内测量ClO、HOCl、HO2、BrO和中间层O3的日变化。smile的高灵敏度（Tsys~ 400k）和日变化为研究平流层和中间层的光化学细节提供了机会。由于SMILES仪器具有更好的Tsys （~400K）和NEΔT (~0.4 K)，因此与以前的卫星测量相比，SMILES数据（O3， HCl等）即2级（L2）数据的剖面预计具有更高的精度（更小的误差条）。由于许多原因，SMILES L2数据的准确性可能不如其精度；如切线高度的确定（Verdes, 2002; Takahashi et al., 2010）、对仪器特性的不了解、光谱误差的不确定性（Verdes et al.， 2005A和2005B）、算法的近似等。众所周知，微量物质ClO、BrO、HOCl、HO2控制着平流层和中间层的光化学变化，且具有日变化特征。由于种种原因，对这些物种的观察一直很困难；1)微弱的信号需要卫星观测的整合，2)太阳同步卫星的当地时间有限，和/或3)具有足够灵敏度的气球仪器的空间/时间覆盖有限。SMILES的灵敏度可以为获得ClO、BrO、HOCl和HO2的单次扫描检索提供机会。通过绘制这些物种在30-45天内的分布图，就有可能得出这些物种在平流层和/或中间层的日变化。本文介绍了SMILES ClO、BrO、HO2检索的现状、验证及其日变化特征。
The Superconducting Submillimeter-Wave LimbEmission Sounder (SMILES) (Kikuchi et al., 2010) is one of the early science program onboard Japanese Experimental Module/Exposed Facility (JEM/EF) of the International Space Station (ISS). SMILES has been developed jointly by JAXA and NICT. SMILES measures Earthʼs limb in the 625650 GHz frequency region by using 4-K cooled Superconductor-Insulator-Superconductor (SIS) junction device, which results Tsys ~ 400K and NEDT ~ 0.4 K, i.e. 10 times higher sensitivity compared to previous limb atmospheric measurements in the mm/submm wavelength region, such as AURA/MLS (Waters et al., 2006) and ODIN/SMR(Frisk et al., 2003). SMILES can measure several key species related to chemistry of O3 layer; O3 (O3, OOO, OOO, OOO, and OOO), HCl (HCl and HCl), ClO, HO2, HOCl, BrO, and CH3CN. The 350-400 km and 52° inclined ISS orbit shows 88-90 days precession period, which means that SMILES can measure diurnal variation of ClO, HOCl, HO2, BrO and mesospheric O3 within 45 days observation. The high sensitivity (Tsys~400 K) and diurnal variation of the SMILES should open opportunity to investigate details of photochemistry of stratosphere and mesosphere which have not been investigated well before. Profiles of SMILES data (O3, HCl, etc), i.e. Level 2 (L2) data, are expected to have better precision (smaller error bar) compared to previous satellite measurements, because of better Tsys (~400K) and NEΔT (~0.4 K) of the SMILES instrument. Accuracy of SMILES L2 data may not be as good as its precision, due to many reasons; such tangent height determination (Verdes, 2002; Takahashi et al., 2010), poor knowledge on instrument characteristics, uncertainty of spectroscopic errors (Verdes et al., 2005A and 2005B), approximations of algorithms, etc. It is well known that the trace species, such as ClO, BrO, HOCl, HO2, are controlling the photochemistry of stratosphere and mesosphere with diurnal variation. Observations of these species have been difficult due to reasons; 1) weak signals require integration for satellite observations, 2) limited local time from sunsynchronous satellites, and/or 3) limited space/time coverage from balloon instruments with enough sensitivity. The sensitivity of SMILES can provide opportunity to derive single scan retrieval of ClO, BrO, HOCl, and HO2. By plotting these species over 30-45 days, it is possible to derive diurnal variation of these species in the stratosphere and/or mesosphere. This paper describes current status of SMILES ClO, BrO, HO2 retrieval, their validation, features in diurnal variation.