We compare ground-based microwave observations of ozone in the upper stratosphere and mesosphere with daytime observations made from the SME (Solar Mesosphere Explorer) satellite, with nighttime data from the LIMS instrument, and with a diurnal photochemical model. The results suggest that the data are all in reasonable agreement and that the model-data discrepancy is much less than previously thought, particularly in the mesosphere. This appears to be due to the fact that the latest data are lower than earlier reports and the updated model predicts more ozone than older versions. The model and the data agree to within a factor of 1.5 at all altitudes and typically are within 20 percent

Connor, Brian J.

Eckman, Richard S.

Parrish, Alan

Remsberg, Ellis E.

Siskind, David E.

Tsou, J. J.

English

NASA Technical Reports Server

N95- 10660
MODEL/DATA COMPARISONS OF OZONE IN THE UPPER STRATOSPHERE AND
MESOSPHERE
David E. Siskind, 1 Ellis E. Remsberg, Richard S. EcDaan, Brian J. Connor
Atmospheric Sciences Division, NASA Langley Research Center, Mail Stop 401B, Hampton, Virginia
23665-5225
J. J. Tsou
Lockheed Engineering and Sdenc_s Company, Hampton, Virginia, 23666
Alan Parris_
University of Massachusetts, Amherst, M,_sa_husetts 01003
AbJtract. We compare ground-based microwave observa-
tions of ozone in the upper stratosphere and mesosphere
with daytime observations made from the SME satellite,
with nighttime data from the LIMS instrument, and with a
diurnal photochemical model. The results suggest that the
data are all in reasonable agreement and that the model-
data discrepancy is much less than previously thought, par-
ticularly in the mesosphere. This appears to be due to the
fact that the latest data are lower than earlier reports and
the updated model predicts more ozone than older ver-
sions. The model and the data agree to within a factor of
1.5 at all altitudes and typically are within 20%.
Introduction
A long standing problem in middle atmospheric sdence is
the fact that photochemical models of ozone from 40 to 80
km have historically predicted significantly less ozone than
is observed. In the review by Rusch and Clancy (1987),
they state that the discrepancy is on the order of 30-50% in
the upper stratosphere, increasing to a factor of 2-3 in the
upper mesosphere. There have been a number of proposals
advanced to try and reconcile the models and the obser-
vations. For example, it has been suggested that the cat-
alytic cycles, such as that due to HO, (Rusch and F.,ckman,
1985) which destroy ozone _e less efficient than currently
assumed. Others have suggested that larger O= photolysis
cross sections axe required (e.g Allen and Delitsky, 1991).
This would then increase the production of odd oxygen.
Finally, there has also been considerable effort to try and
identify a missing ozone source that is not included in the
current chemical scheme (e.g. Slanger et al., 1988).
Recently, Natarajan and CMiis (1989) have pointed out
that the discrepancy in the upper stratosphere can be
reduced somewhat if updated rate coefficients and solar
fluxes are used in their model along with the somewhat
lower total chlorine estimates obtained from the ATMOS
data. On the other hand, Alien and Delitsky (1991) ar-
gue that by combining the analysis of stratospheric and
mesospheric ozone from ATMOS, a consistent, significant
discrepancy still exists.
InowatNavaaResearchLaboratory,Code 4141, WMhington DC,
20375
_AlsoatM/llitechCorporation,Deerfield,MA, 01373
In this paper we pursue the question of the model-data
comparison using a variety of datasets including that from
the Solar Mesosphere F._plorer (SME) for the daytime
meaosphere, from the Limb Infrared Monitor of the Strato-
sphere (LIMS) for the nighttime upper stratolphere and
meso, phere and from ground-based microwave data which
span the altitude region from 40 to 70 km for both day and
night conditions.
Comparison of Observational Data
Figure 1 presents an overview of the ozone data used in
our study. The data are all mean profiles for the month
of March, at a latitude of 35N, and include both day and
night conditions. Although the measurement set spans 12
years (1979 for LIMS, 1982 for SME, mad 1991 for the mi-
crowave) these data were all obtained during comparable
solar activity conditions, near the maximum of either cy-
cles 21 or 22. The figure shows s consistent pattern in
that the nighttime data exceed the daytime data, by an
amount which increases with decreasing pressure. This
reflects the well known mesospheric diurnal variation of
ozone whereby atomic oxygen recombines after sunset to
increase the ozone density (Zommerfelds et al., 1989). Spe-
cific features of these profiles will be discussed below.
The LIMS data that we used were described by Ren_beag
et al. (1984) and consist of zonal mean ozone data up to
0.1 rob. We have exdrmively u_ed nighttime data in order
to avoid the non-LTE e_ects known to be present above
about 0.5 mb in the daytime data (Solomon et al., 1986).
SME measured ozone from 1982 to 1986 using an ultravi-
olet absorption (UVS) technique from 1.0 to 0.1 mb (Rusch
et aS., 1984) and a near infrared (NIR) emission technique
from 0.75 to 0.002 mb (Thomas et al., 1984). Both tech-
niques are vaJdd during daytime conditions only. The SME
dataset was reprocessed in 1988 (WMO, 1988) and we used
this dataset for our study.
The microwave data come from an instrument at the Ta-
bleMountain Observatory (34 deg N, 118 deg W). The in-
strument was developed at the Millitech Corporation and
the data is processedat NASA's Langley Research Cen-
ter. The data cover the altituderange from 20 to 70 km
(.05rob)and record an observationevery 20 minutes. A
complete descriptionofthe instrument,the observingtee.h-
294
https://ntrs.nasa.gov/search.jsp?R=19950004248 2020-06-16T11:27:06+00:00Z
Average March Ozone Profiles
,-,AE0.1 __
................. LI
.......... Microwave (ff_ght) _"
...... Microwave(day) _ %_
a. 1.0 __ SMEUVS(day) _*
.... SME NIR (day) .,_\
x
0.1 1.0 10.0
Mixing Ratio (ppmv)
Fig. 1. Summary of monthly mean ozone datasets for
35N latitude. The LIMS data are from March 1979, the
SME data from March 1982, and the microwave data from
March 1991.
nique and calibration method are described in Parrish et
al., (1992). The retrieval method is described by Con-
nor et aJ., (1991). Comparisons of these data with other
ground and satellite obsevations are given bY Parrish et
al., (1992, these proceedings). It is important to note that
the microwave experiment has much lower vertical resolu-
tion than the llmb scanning satellites (12-16 km for the
microwave, 3-4 km for LIMS and SME). Thus, in the dis-
cussion which follows we will convolve the high resolution
satellite data (as well as tile photochemical model) with
the microwave averaging kernels as described by Connor
et al. (1991).
Figure 2 shows March mean daytime ozone profiles from
the SME NIR instrument from 1982 and the ground based
microwave from 1991. Both the SME and the microwave
data are for 1500 hours local time. Also shown in the fig-
ure is the SME data after convolution with the microwave
averaging kernel. The effect of the convolution process is
most noticeable at the lowest pressure (.05 rob). The figure
shows that the convolved SME agrees with the microwave
to within the estimated errors of the two experiments (25%
for the microwave at .05 rob, 15-20% for SME). It should
be noted that the narrower pressure range covered by the
UVS instrument (1.0 to 0.1 mb) precludes a direct inter-
comparison with the low resolution microwave. On the
other hand, in the next sectionwe will compare allthree
daytime ozone profilesto a photochemical model.
Figure 3 shows the ratioof the nighttime LIMS to the
nighttimemicrowave. Because the LIMS data only extend
up to 0.1 rob,itisnecessaryto extrapolatethe data up to
0.01 mb in order to convolve with the microwave averag-
ing kernels.The threecurvesin Figure 3 show the results
for three differentextrapolations.The solidlineuses a
profiletaken from the photochemical model (discussedbe-
low),normalizesitto the LIMS data at 0.1 mb and then is
used to extend the data up to 0.01rob.Using thisextrap-
olation,we findthat the LIMS and the microwave data
agree to within 5% at allaltitudes.The leftdotted line
simply assumes a constant rni_ng ratiofrom 0.1 to 0.01
rob,whilethe rightdotted lineusesthe microwave a priori
profileabove 0.Irob.The purpose of the two dottedcurves
SME vs Microwave: March
0.01
* __ Microwave
+
_" * + SME NIR
....... Convoht_l
olO s.E.,,
(n
(n
n
1.00 .....
0.1 1.0 10.0
Mixing Ratio (ppmv)
Fig. 2. Daytime ozone data. The dotted line is the SME
NIR mean data for March 1982, the solidline is the mesa
microwave data for March 1991. The dashed curve is the
SME data after convolving with the microwave averaging
kernels.
is to show that although the agreement between LIMS and
microwave is excellent everywhere, there is a mathematl-
cal uncertainty of %/- 10% at the top of the profile which
results from the need to extrapolate the LIMS data.
Photochemical Model Calculations
The model we use is a one dimensional photochemical
model of the middle atmosphere from 40 to 80 kin. It has
evolved from the model used by Rusch and Eckman (1985)
to study daytime mesospheric ozone. For the present ap-
plication we have expanded its capabilities in three ways.
First, we now use complete spherical geometry to calculate
the attenuationofthe solarUV radiationby ozone and thus
improve the O= and Os photolysiscalculationsduring twi-
light. Second, while the previous model used the family
method to combine O and Os as O,, we now calculatethe
O and O_ densities eparatelyforaltitudesgreaterthan 60
km and forsolarzenithanglesgreaterthan 92°. Third, we
now account foraccount the enhanced photolysisof Os and
NO= at near UV and visiblewavelengths by inputtinga ts-
Microwave/Convolved LIMS: March
0.01
°'1° I
O0 I
U. 1.
lo.ooi
0.6 0.8 1.0 1.2
Ratio
1.4
Fig. 3. Ratio of microwave to convolved LIMS. Three
differentassumptions were used to extrapolatethe LIMS
data above 0.i mb when performing the convolution(see
text).
2t_5
hie d soatte_ng enhancement factors which depend upon
alt/tu_e and solar zenith angle.
The mode] uses fixed chlorine (Cl, = HCI + HOCI + ClO
+ CI),nitrogen (NO. = NO + NO2), sad water vapor in-
l_tl. For Cle, we used a constant value of 2.2 ppbv for
the compar/son with the LIMS data, 2.4 ppbv for the com-
psrkoa with SME, and 3.0 ppbv for the comparison with
the m/crowave data. These chlorine quantities are consis-
teat with that used by Natarajan and CaUis (1989) and are
than those used in earlier studies. For NO., we used
a Ixed value of 15 ppbv, except for the LIMS comparison
where we used the LIMS nighttime NO2 measurement as
an fladicator of the total NO,. Our assumed water vapor
prcdl]e is taken from the LIMS climatology (Remsberg et
s]., 1990) for the stratosphere and the microwave data of
Bev/lacqua et al. (1989) for the mesosphere. Finally, the
model uses different temperatures when comparing with
different datasets: for the LIMS comparison, simultane-
ously measured LIMS temperatures are used, for the nil-
crowave comparison, the temperatures are those used in
the data processing, and for SME, the reference cl/matol-
ogy of Cole and Kantor (1978) was adopted.
One limitat/on of the model is its neglect of vertical trans-
port. While this WIU not be important for altitudes where
the lifetime of ozone is short (< 75 kin), it could introduce
an uncertainty when comparing with the low resolution
microwave data at 70 kin. We therefore have limited our
comparison of the microwave data and the convolved model
to altitudes below 66 km (0.i rob).
Figure 4a compares the ratio of the two nighttime
datasets to either the model (in the case of LIMS) or the
convolved model (for the microwave). A similar compari-
son with the March LIMS data was presented by Natara-
jan and Calfis (1989); however, their analysis only went
up to 0.5 mb (52 kin). Here, we extend the comparison
up to 0.1 mb. The figure shows that the data exceeds the
model at all pressures, consistent with all previous studies
of the problem. The dete_led shape of the difference agrees
very well with that seen by Natarajan and CaJlis in the
pressure range where our two studies overlap, a minimum
from 1.0 to 0.5 mb with a maximum at 3 mb. In addi-
tion, our analysis suggests that the discrepancy increases
above 0.5 mb to reach a maximum of a factor of 1.3 at
0.1 rob. Also, the figure shows remarkable agreement be-
tween the LIMS and microwave comparisons, despite the
different inputs to the model (described above) and the 12
year separation in the observations. Given the lack of other
nighttime mesospheric ozone measurements, the combina-
tion of this comparison and that shown in Figure 3 serves
as the first reliable validation of the LIMS nighttime ozone
in the mesosphere.
Figure 4b presents a similar model-data comparison for
the three daytime data sets. It shows the ratio of the three
daytime datasets to either the model (in the case of SME)
or the convolved model (for the microwave). At 1.0 rob, the
UVS and the microwave data exceed the respective model
by a factor of 1.15-1.20. At pressures below 1.0 rob, the
discrepancy between the model and the UVS worsens to
reach a factor of 1.35 at 0.3 mb. The discrepancy between
the microwave and the SME NIR show somewhat different
behavior and seem to agree slightly better. Above 0.1 mb
March Nighttime Ozone
t'
o.1f• ./
Microwave/ConvolvedMod_
i , i , J , , i , , ,
1.0 1.2 1.4
Data/Model Ratios
J
I
1.6
March Daytime Ozone
I:........... N, Mo e,
0.1 _-
1.0
w'- J
, ...... I UVS/M_al i
,, +'
Microwave/Convolved Model
• ,,
t i h , , , J , , J
1.0 1.2 1.4 1.6
Data/Model Ratios
Fig. 4. (a) Ratio of March nighttime ozone to photo-
chemical model (in the case of LIMS data- solid line) and
eonvolved model (for the microwave- dotted line). (b) Ra-
tio of March daytime ozone to photochemical model (solid
line is for the SME UVS data, the dotted llne is for the
SME NIR data) and with convolved model (dashed line-
for the microwave data).
the model and the NIR data come into closer agreement.
The pattern here is not as consistent as that seen in Figure
4a. Part of this undoubtedly reflects the 2{3% disagreement
which exists between the two simultaneous SME measure-
ments at certain pressures (e.g 0.4 mb). In addition the
temperatures used in the comparison between the model
and the SME datasets, which are from the Cole and Kan-
tor (1978) climatology, may not be as realistic as those
used in analysing the microwave data (from the N_tional
MeteorologicalCenter analysis sad the MAP climatology).
Discussion
In both Figures 4a and 4b, the data-model ratiosaxe
lower than previouslyreported. For example, using SME
UVS data from 1983,Rusch mad Eckman (1985)reported
a discrepancyof 1.8 during March at 40 N, with a larger
discrepancy during winter. Here, however, the peak dis-
crepancy from all5 ozone observationsliesin the range
1.2 - 1.35. One reason for thischange isthat the model
now uses a fasterOH + HO2 ratecoefficient(seeJPLg0
fora disussion)and thuspredictslessHO. and about 1.15
times more ozone at 0.1 rob.Second,the reprocessedSME
296
data is genera£1y lower than the original version used by
Rusch and Eckman (1985). Some of this is discussed in
the WMO (1988) report and is attributed to a removal of
a calibration drift, corrections to the field of view and the
determination of tangent point altitude as well as a 12%
change in the absolute calibration of the NIR instrument
(R. Thomas, private communication, 1992). A example of
the difference is shown in Figure 5 which compares the new
SME NIR data for March 1982 with the version 1 data ms
given the MAP Handbook (1985). It can be seen that at
0.1 rob, the old data is more than 1.3 times greater than
the new. The combination of the newer, lower data (factor
of 1.2 - 1.4) and the higher model (factor of 1.10 - 1.15)
leads to a significantly reduced discrepancy between model
and data.
Summary
We have compared ground based microwave data with
satelliteobservationsfrom LIMS and SME. For both day
and night,the observationsagree to within 25%. When
compared to photochemical model calculations,the data
exceed the model at allaltitudes,but by an amount which
ismuch smallerthan earlierreports. This is because the
revisedmodel predictsmore ozone while the newer obser-
vationsreportless.
Acknowledgments. We acknowledge the National Space
Science Data Center and Charles A. Barth, PrincipalIn-
vestigator,forsupplying the SME data.We alsothank R.
Thomas and M. Callan for assistancein using thisdata.
References
Allen,M. and M. L. Delitsky,A testofodd-oxygen photo-
chemistryusingSpacclab 3 Atmospheric Trace Molecule
SpectroscopyObservations,J. Geophys. Res.,96, 12,883,
1991.
Bcvilacqua,R. M., J.J. Olivcro,and C. L. Croskey,MesoJ
spheric water vapor measurements from Penn State:
Monthly-mean observations (1984-1987), J. Geophys.
Res., 9_, 12807, 1989.
Connor, B. J. A. Parrish,and J. J. Tsou, Detection of
stratosphericozone trends by ground-based microwave
observations,Proc. of SPIE con].I._91,Remote Sensing
of Atmsopheric Chemistry, Soc.of Photo-Opt. Instrum.
Eng., Bellingham, Wash., 1991.
Cole, A. E. and A. J. Kantor, Air Force referenceat-
mospheres, Rep AFGL-TR-78-0051, Air Force Geophys.
Lab.,Cambridge, Mass., 1978.
NASA-JPL, Chemical kineticsand photochemical d.atafor
use in stratosphericmodeling, Evaluation No. 9, JPL
publication90-1,Jet Propulsion Laboratory,Pasadena,
California,1990.
Natarajan, M. and L. B. Callis,Examination of strato-
spheric ozone photochemistry in lightof recent data,
Geophys. Res. Lett, 473, 1989.
Parrish, A., B. J. Connor, J. J. Tsou, I.S. McDermid, W.
P. Chu, Ground-based microwave monitoring of strato-
spheric ozone, J. Geophys. Res., 97, 2541-2546, 1992.
A
fL
Version 1/Revised SME NIR Data
I March, 35N ' '1117-_
/
!
f
1.0 ............................... I
1.00 1.10 1.20 1.30 1.40 1.50
Ratio of Data
Fig. 5. A comparison of version 1 and the revised SME
NIR for March 1982. The older dataset (version 1) contmns
larger values.
Remsberg, E. E., J. M. Russell, III, J. C. Gille, L. L. Gord-
ley, P. L. Bailey, W. G. Planet, and J. E. Hurries, The
validation of Nimbus 7 LIMS measurements of ozone, J.
Geophys. Res., 89, 5161, 1984.
Remsberg, E. E., J. M. Russell III, and C. -Y. Wu, An
interim reference model for the variability of the middle
atmosphere water vapor distribution, Adv. Space Res.,
10, 51, 1990.
Rusch, D. W. and R. T. Clancy, Minor constituents in the
upper stratosphere and mesosphere, Rev. Geophys., _5,
479, 1987.
Rusch, D. W. and R. S. Eckman, Implications of the
comparison of ozone abundances measured by the Solar
Mesosphere Explorer to model calculations, J. Geophys.
Res., 90, 12991, 1985.
Rusch, D. W., G. ft. Mount, C. A. Barth, R. J. Thomas,
and M. T. Callan, Solar Mesosphere Explorer ultraviolet
spectrometer: Measurements of ozone in the 1.0 to 0.1
mb region, J. Geophys. Res,, 89, 11677, 1984.
Russell, J. M. III (Ed.), Handbook for MAP, $$, 302pp.,
University of Illinois, Urbana, 1986.
Slanger, T. G., L. E. Jusinski, G. Black, and G. E. Gadd,
A new laboratory source of ozone and its potential at-
mospheric implications, Science, _1, 945, 1988.
Solomon, S., J. T. Kiehl, B. J. Kerridge, E. E. Remsberg,
and J. M. Russell III, Evidence for non.local thermody-
namic equilibrium in the Us mode of mesospheric ozone,
J. Geophys. Res., 91, 9865, 1986.
Thomas, R. J., C. A. Barth, D. W. Rusch, and R. W.
Sanders, Solar Mesosphere Explorer near-infrared spec-
trometer: Measurements of 1.27pm radiances and the
inference of mesospheric ozone, J. Geophys. Res., 89,
9569, 1984.
WMO, Report of the international ozone trends panel
1988, WMO Global Ozone Research and Monitoring
Pro3ect Report No. 18, WMO, Geneva, 1988.
Zommerfelds, W. C., K. F. Kunzi, M. E. Summers, R.
M. Bevilacqlla, D. F. Strobel, M. Allen, and W. J.
Sawchuck, Diurnal variations of mesospberic ozone ob-
tained by ground based microwave radiometry, J. Geo-
phys. Res., 9._, 12,819-12,832, 1989.
297


Model/data comparisons of ozone in the upper stratosphere and mesosphere

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