Level 2 Product Ver. 2.0 (007-08-0300) Release Notes
October 3, 2011
SMILES Office, Japan Aerospace Exploration Agency
We request that the version 2.0 data (hereafter refered to as “v2.0”) should be used very
cautiously for scientific purposes, under the condition that you know characteristics ofthe data well. This product will be released to the general users (not limited within
SMILES RA researchers) soon.
1.

SMILES observation

SMILES observes 624-650 GHz in three bands defined as bands A, B, and C. Since
the SMILES instrument consists of two receivers, emission in band A can bemeasured by different receivers according to the combination of observed bands.

The period of coverage is from October 12, 2009 to April 21, 2010.
From November 30 to December 15, 2009, the ISS solar paddle stopped just in
front of the SMILES IFOV due to the maintenance of the Port Solar Alpha
Rotary Joint elements of the ISS.



From February 25 to March 5, 2010, the number of L1B data is only around
10% of ordinary condition, due to trouble of communication system of ISS/JEM(not according to SMILES itself).

2.

Two types of L2 Products

There are two types of products.
L2Product_G_RA (0.8 MB/file, 1 file/day/molecule)This product has minimum information such as retrieved profiles,precisions and a simple status flag.

The profile data derived from single observation band are contained in theproduct, according to the priority (see Table 1) and the number of available
profiles day by day. Therefore, it should be noted that the observation bandmay not be continuous, though the data series itself continuous.

L2Product (8MB/file, 1 file/day/molecule/band)This product has detailed information, such as a detailed status flag, apriori profiles and averaging kernels. Refer to the Product Guide fordetails.

The profile data derived from all observation bands are contained in thisproduct.
‐ 1 ‐Table 1 standard products and ban priority
ProductPriority

ProductPriority

ProductPriority

O3

A, B(, C)

HCl

B, AClOC

HNO3C(, A)

HOClA

CH3CN

A

BrO

C(, A)HO2

B, C

Temperature

A, B

17C

O17OO

B

18

B, COOO

OOO

3.

Data screening for scanThis version of the L2 product includes all the processed profiles, so some of them
are inadequate for scientific use. In using these profiles, it is strongly recommended
to pick up usable ones according to the following screening conditions (see Table 2,Figure 1, and Figure 2); also please look at 4. Data screening for Altitude as to theusable altitude range for each species.
Quick method: Users check only a Status field and can reject inadequate scans.
A Status field has a value 0 only in case that all of FOV interference,
observation altitude range, and convergence status are qualified (see Table3). This criterion gives priority to the data quality over the number ofavailable data, therefore about 30 to 60% (depend on the observation band)of scan data will be removedAdvanced methods: Users check individual fields that show error status.
The 1st bit of Status field shows the error flag of FOV interference. Whenthe interference is predicted (the FOVInterference field > 0) or forecast
information is lost (FOVInterference = -1), this flag is set. (see Table 4) .
About 20% of the profile data will be removed with this criterion. However,this constraint is very “conservative”, therefore about 70% of removed data
may be adequate to use. If you want to utilize as more data as possible, you
may ignore this flag.

The 2nd bit shows the error flag of observation altitude range. You may notignore this flag.

The 3rd bit shows the error flag of convergence of the retrieval process.
When the convergence is not well (the Convergence field > 1), this flag isset. However, in case of the species which has strong spectral line (such as
O3, HCl, and ClO), you may ignore this flag and apply “looser” constraint
such as Convergence < 10, because the retrieved profiles of those species
are relatively good even the retrieval process was not well converged.
‐ 2 ‐Especially in case of band C, if you apply the constraint Convergence < 10,
you can obtain 30% more available data than those by the screening resultwith this flag.
Table 2Sam ples of screening condition

Useful condition

Quick

Status = 0

Advanced 1(except for
O 3 , HCl, ClO)
Advanced 2(for O 3 , HCl, ClO)

Convergence = 1or 3rd bit of Status = 0nd
2 bit of Status ＝ 0Convergence < 10
2nd bit of Status ＝ 0

Usable products
typeL2Product
L2Product_G_RA
L2Product
L2Product_G_RA
L2Product only

Table 3 Status field
Value0>0124Explanation
No error status
ERROR status, Do not use this profiles
FOV interference error ( FOVInterference ≠ 0)
Observation altitude error
Convergence status error ( Convegences > 1)

Table 4 FOVInterference field
Value-10>01
24Explanation
No interference forecast information
No FOV interference
Do not use this profile
Information: FOV interference by Sun
Information: FOV interference by Moon
Information: FOV interference by ISS Solar paddle‐ 3 ‐Usefuldata(%)
ABC685938837545929072

Figure 1: The num ber of screened scan data. Green: screened with “Quick”
condition, Blue: additionally screened with “Advance1” condition, Light
blue: additionally screened with “Advance2” condition, Red: without
any conditions, Gray: not contained within L2 products.

‐ 4 ‐a) Quickb) Advanced 1c) Advanced 2d) No screening

Figure 2: Exam ples of screening results projected on the latitude-tim ecross-section. Observation data from Novem ber 1 to 10, 2009, at thealtitude of 28km (only from ascending orbits). Left: O 3 , from Band A,.
Right: BrO, from Band C.

‐ 5 ‐	  4.

Data screening for Altitude

The L2 products include data for altitude range not usable to validation and/orscience. If the L2Precision is more than 50% compared to the AprioriError, it isprobable that L2 algorithm is just answering a priori. In this case, the value ofL2Precision was turned into negative. (L2Precision and AprioriError are defined as
HDF EOS5 names in the SMILES L2 products.)
5.

Improvements in v2.0 updates

L1B data have been updated from version 006 to 007.
Gain nonlinearity correction has been applied to observed spectra (Ochiai et al.,2011). In the middle stratosphere, retrieved temperatures become closer tothose of Goddard Earth Observing System-5 assimilated data. Nonlinearity
effects influence not only temperature but also other molecules. For thosespecies such as O3, HCl and ClO with strong lines the retrieved values decreaseby 5 – 7% in 25 – 45 km. For those species such as HOCl and BrO with weaklines located at the wing of strong lines the retrieved values change about 50 –100 %. In v1.3, the retrieved profiles of HOCl contained negative values around
30km, but it is now improved.

New AOS response function has been introduced. This function is modeled by new
on-orbit measurement data for AOS response function in January of 2011 (Ozeki etal., 2011).
Temperature field in the mesosphere is very sensitive to the retrieval results, butthe retrieved temperature profiles above 40- 50 km were not so good. Thus MLS
temperature products (v2.2) with applying migrating tidal model (Global Scale
Wave Model) was referred as the mesospheric temperature field.

Preliminary correction in observed frequency grids has been introduced. By
removing residue of frequency fitting in L1B data, the residue is decreased from100 kHz to 50 kHz.

Some line parameters have been updated (see Table 5).

Bugs in frequency grids around O17OO (Band B) and 18OOO (Band C) have beenfixed. This update reduces systematic error above 50km.

‐ 6 ‐Table 5 updated line param etersParameters
O3(MHz/hPa)-H 35 ClLine position(MHz)(MHz/hPa)
H 37 ClLine position(MHz)(MHz/hPa)
ClOLine position(MHz)
18 OOOLine position(MHz)

L2 v1.3

v2.0

Reference

624371.112

624371.223

2.258
0.77

2.30780.78

Ozeki private communication(preliminary results)
HITRAN2008
HITRAN2008

625901.603
625918.756
625932.007
2.57
0.73

625901.6584
625918.6975
625932.0081
2.541
0.723

Colmont et al., 2005

624964.374
624977.821
624988.334
2.57
0.73

624964.3694
624977.8013
624988.2821
2.541
0.723

Colmont et al., 2005

649445.040
649451.170

649445.250
649451.072

Oh and Cohen, 1994

649137.611
649137.611
649149.603
649152.601

649137.132
649137.132
649152.038
649152.038

Ozeki private communication(preliminary results)

MLS Forward model ATBD (v1.0)
MLS Forward model ATBD (v1.0)

MLS Forward model ATBD (v1.0)
MLS Forward model ATBD (v1.0)

6.

Newly Found Issue in ver. 2.0

In 30-40km, the retrieved values of HOCl may still have large positive bias. We
found that line parameters of O3(v1,3) are key factors since HOCl spectral lines arelocated at the shoulder of this line, and we have already performed several test
runs to check this. In the next version, it will be improved.

Convergence state in band C is not good. Only 40 – 50% of scans satisfy convergencecondition, while 70-80% of scans satisfy in case of band A and B. We try to improve
this by taking into account results from Band A or B.

Dicke narrowing effect was not considered and the profiles in upper mesosphere
may have negative bias. However, we have found this effect is actually small.

Zeeman splitting is not implemented to ClO, BrO, and HO2 in forward model
calculation, which may affect these products above 60km.

Frequency calibration in the L1 processing has a long-term drift.

7.

Remaining Issues

HOCl, HNO3 (in band A) and BrO data (in band A) look not usable. [Continuing‐ 7 ‐from v1.0]
We recommend zonal mean processing on using CH3CN, BrO (in band C), HNO3 (inband C) and HO2 data.

Checking of O3 isotope products have not been sufficiently done yet. [Continuingfrom v1.0]

According to the change of retrieval altitude grid, altitude grids of the species insingle product are not uniform. In the future, we consider to apply the pressuregrids uniformly among the species. In addition, we are studying some
improvements of L2 retrieval algorithm. [Continuing from v1.3]

References
Ochiai, S., Kikuchi, K., Nishibori, T., Mizobuchi, S., Manabe, T., Mitsuda, C., and Baron,P., 2011, "Gain nonlinearity calibration of the SMILES receiver," IEEEInternational Geoscience and Remote Sensing Symposium, Vancouver, 3610
Ozeki, H., Tamaki. K., Mizobuchi, S., Mitsuda, C., Sano, T., Suzuki. M., Kikuchi, K.,and Shiotani, M., 2011, "Response characteristics of radio spectrometers of theSuperconducting Submillimeter-Wave Limb-Emission Sounder (JEM/SMILES),"IEEE International Geoscience and Remote Sensing Symposium, Vancouver,
3619

‐ 8 ‐

AppendixesDescription in v1.0


The tangent altitude (geometrical) is calculated by using a) SMILES StarSensors, b) SMILES scan mirror angle, and c) ISS position. SMILES starsensor shows unexpected large scattered output. We smoothed out the SMILES
tangent altitude by second order fitting in this version. The tangent altitude
precision should be 100 m (1 sigma) in rms by the specification, which is now
under verification.

The two SMILES star sensors are pointing somewhat close direction each other,thus there is possibility that the SMILES tangent point cannot be calculated
when both the sensors are within 45° to the Sun. In this situation, no L2
product is processed.

The tangent altitude for L2 data is retrieved as an altitude offset.

Condition of vertical correlation is not introduced in the retrieval of all species
except temperature, according to the result of vertical correlation study.

Improvements at v1.1 updateThe pointing direction for determining tangent altitudes (geometrical) is
calculated by using SMILES scan mirror angle and ISS position. However,since the pointing accuracy heavily would affect to error of tangent altitude
determination, an average altitude within single scan is retrieved with using
the Star Sensor of SMILES in L2 processing. In case that sunlight or
moonbeam enters in the FOV of SMILES Star Sensor, positioning information
cannot be obtained, so it will be estimated from the information of 50 scansaround the scan in such cases.

Improvements at v1.2 updateIllegal value in longitude in case the longitude of tangent point is around 180
degree, has been corrected.

Altitude offset of Star Trackers (STT) has been reduced to +/- 1km, according to
implementation of compensation formula of time from STT.

Rate of convergence in the retrieval process has been improved, by smoothing
vibrations in the ISS altitude data which do not seem to represent actualvibrations.

Description of line shape has been refined with introducing the coefficient
‐ 9 ‐

.


Line parameters of O3, HNO3, HO2 and ozone isotopes have been changed fromthe JPL catalog to HITRAN2008.

Profiles of temperature and HCl around 50km have been improved, withcompensation of an effect from the Doppler shift.

Consistency between retrieval results from band A in Setting 2 (band A/C) andSetting 3 (band B/A) have been improved, by taking compensation between theresponse function of AU1 and AU2 (2 units in AOS).

Hydrostatic assumption has been introduced as a constraint in the calculationof pressure and temperature.

Retrieval results of HOCl have been improved, by ignoring ozone isotopes
whose absorption lines overlap that of HOCl in band A.

Information contents of ozone isotopes, HNO3, ClO and CH3CN have been
increased, by adjusting the error value in a priori profile.

Rate of convergence in the retrieval process has been increased, by ignoring
temperature retrieval in band C.

Rate of convergence in the retrieval process has been increased, by raising
upper limit of iteration trials in the retrieval process from 5 to 8.

Improvements at v1.3 update

L1B data have been updated from version 005 to 006. The retrieved profiles
from the scans near “FOV interference” were improved by referring “the flagsindicating FOV disturbance.” For details of L1B data update, see the document“Level 1 Product Release Notes (Ver.006)”.

Standard temperatures for Lorentz width of absorption lines of O3, HNO3, HO2and ozone isotopes have been corrected from 300K to 296K. The effect for thiscorrection is around a few percent.

In correcting the tangent height on the observation point, it is introduced thatthe antenna elevation offset is retrieved from the average of altitude offset
within one scan. According to this change, O3 and HCl above 50km increase afew percent.

Antenna movement within the time to acquire a spectrum for single height istaken into account with the antenna pattern. This improvement causes a few
percent increase of ozone at the peak height (lower stratosphere).

In order to make better fitting of the curved baseline of brightness temperature,
the uncertainty of absorption coefficient is fitted with 2-dimensional function‐ 10 ‐

instead of 1-dimensional. As a result, residue of the baseline has been
decreased to about a half in comparison with the previous version.
Regularization of status vectors in the inversion model with a priori error havebeen introduced. According to this improvement, 2-dimensional term of theabsorption coefficients with small number of digits can be retrieved.

The grids of retrieval altitude have been adjusted 2, 3 or 4 km depending onspecies, band and altitude, instead of uniformly 3km in the previous version. Inadjusting the altitude grid, the information of altitude resolution is referred. Asa result of this modification, the species with high sensitivity (such as O3 andHCl) can be retrieved with more precise altitude grid, and the one with low
sensitivity (such as BrO and HO2) can be retrieved with wider altitude range.

The altitude correlation of 10km has been introduced for all products except O3
from band A and B.

The information of convergence, FOV interference and observation altitude arestored in the status field. For details, see the format sheet in the Product Guideof v1.3.

In order to evaluate the residue of spectrum, the cost function for all species
and all altitudes are stored in the CostFunctionY and CostFunctionYAll fields
in the products.

Bugs in the AveragingKernel, InformationValue and VerticalResolution fields
have been fixed.

Preliminary “status flag” has been newly added from this version.

For the retrieval of Band C, a priori value of the tangent altitude is provided
from Band A or B. (There are operational modes with Band A+C and Band
B+C.)

‐ 11 ‐