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NASA NTRS2017

Atmospheric Ozone Response to the Disrupted 2015-2016 Quasi-Biennial Oscillation

The quasi-biennial oscillation (QBO) - a quasi-periodic alternation between easterly and westerly zonal winds in the tropical stratosphere - is a main driver of inter-annual ozone variability in the stratosphere. During the late-2015 through 2016 time period, the QBO experienced a major disruption unlike any observed since wind measurements began in 1953. We examined the ozone response to this QBO disruption using profile ozone measurements from the Aura Microwave Limb Sounder (MLS) and Ozone Mapping and Profiler Suite Limb Profiler and total column measurements from the Solar Backscatter Ultraviolet (SBUV) Merged Ozone Data Set (MOD). Positive anomalies in stratospheric equatorial O3 developed between 50 and 30 hPa in May-September of 2016, and negative ozone anomalies were observed in the subtropics of both hemispheres. As a consequence of this QBO disruption, extratropical total ozone values during the spring-summer 2016 were at or near seasonal record lows over the more than 40 years of the total ozone record, resulting in an increase of surface UV index during northern hemisphere summer. We found very consistent responses in all considered ozone observations in terms of time, amplitude and spatial patterns. We will show the ozone changes associated with this disrupted QBO throughout the winter and spring 2017.

Kramarova, N. A.↗
NASA NTRS2008

Lidar Measurements of Stratospheric Ozone, Aerosols and Temperature during the SAUNA Campaign at Sodankyla, Finland

The Sodankyla Total Column Ozone Intercomparison (SAUNA) campaign took place at the Finnish Meteorological Institute Arctic Research Center (FMI-ARC) at Sodankyla, Finland (67.37 N) in two separate phases during early spring 2006, and winter 2007. These campaigns has several goals: to determine and improve the accuracy of total column ozone measurements during periods of low solar zenith angle and high total column ozone; to determine the effect of ozone profile shape on the total column retrieval; and to make validate satellite ozone measurements under these same conditions. The GSFC Stratospheric Ozone Lidar (STROZ), which makes profile measurements of ozone temperature, aerosols and water vapor participated in both phases of the campaign. During the deployments, more than 30 profile measurements were made by the lidar instrument, along with Dobson, Brewer, DOAS, ozonesonde, and satellite measurements. The presentation will concentrate on STROZ lidar results from the second phase of the campaign and comparisons with other instruments will be discussed. This will include both ground-based and satellite comparisons.

McGee, T.↗
NASA NTRS2007

An Ozone Increase in the Antarctic Summer Stratosphere: A Dynamical Response to the Ozone Hole

Profiles of ozone concentration retrieved from the SBUV series of satellites show an increase between 1979 and 1997 in the summertime Antarctic middle stratosphere (approx. 25-10 hPa). Data over the South Pole from ozone sondes confirm the increase. A similar ozone increase is produced in a chemistry climate model that allows feedback between constituent changes and the stratospheric circulation through radiative heating. A simulation that excludes the radiative coupling between predicted ozone and the circulation does not capture this ozone increase. We show that the ozone increase in our model simulations is caused by a dynamical feedback in response to the changes in the stratospheric wind fields forced by the radiative perturbation associated with the Antarctic ozone hole.

Stolarski, R. S.↗
NASA NTRS1984

The validation of Nimbus 7 LIMS measurements of ozone

Approximately seven and one half months of stratospheric ozone profiles have been processed from the LIMS (Limb Infrared Monitor of the Stratosphere) experiment on the Nimbus 7 satellite. Data profiles cover the stratosphere and mesosphere from 100 to 0.1 mbar and from 84 degrees N to 64 degrees S latitude. Topics covered include the ozone channel characteristics, precision, systematic uncertainties, and comparisons with data from balloon and rocket underflights, Umkehr soundings, and Dobson measurements. Comparisons with Dobson total ozone are made by integrating combined LIMS plus balloon profiles. The estimated on-orbit precision is 0.02-0.16 ppmv. Simulations of the experiment indicate potential systematic uncertainties ranging from 15 percent in the 1-mbar region to an upper limit of 40 percent at 100 mbar and 0.1 mbar. Results are well within the uncertainties for the correlative sensors themselves. LIMS detects significant vertical structure in the ozone profile even below the ozone mixing ratio peak. Several other comparisons showing good agreement are noted.

Remsberg, E. E.↗
NASA NTRS2006

Exploration of OMI Products for Air Quality Applications Through Comparisons with Models and Observations

The Ozone Monitoring Instrument (OMI) on board NASA s Aura satellite was launched in July 2004, and is now providing daily global observations of total column ozone, NO2, and SO2, as well as aerosol information. Algorithms have also been developed to produce daily tropospheric ozone and NO2 products. The tropospheric ozone product reported here is a tropospheric residual computed through use of Aura Microwave Limb Sounder (MLS) ozone profile data to quantify stratospheric ozone. We are investigating the applicability of OMI products for use in air quality modeling, forecasting, and analysis. These investigations include comparison of the OMI tropospheric O3 and NO2 products with global and regional models and with lower tropospheric aircraft observations. Large-scale transport of pollution seen in the OM1 tropospheric O3 data is compared with output from NASA's Global Modeling Initiative global chemistry and transport model. On the regional scale we compare the OMI tropospheric O3 and NO2 with fields from the National Oceanic and Atmospheric Administration and Environmental Protection Agency (NOAA/EPA) operational Eta/CMAQ air quality forecasting model over the eastern United States. This 12-km horizontal resolution model output is roughly of equivalent resolution to the OMI pixel data. Correlation analysis between lower tropospheric aircraft O3 profile data taken by the University of Maryland over the Mid-Atlantic States and OMI tropospheric column mean volume mixing ratio for O3 will be presented. These aircraft data are representative of the lowest 3 kilometers of the atmosphere, the region in which much of the locally-generated and regionally-transported ozone exists.

Pickering, K. E.↗
NASA NTRS1994

Characterization and analysis of the Nimbus-7 SBUV data in the non-sync period (February 1987 - June 1990)

The SBUV instrument, on Nimbus-7, measures the backscatter ultraviolet radiance at 12 wavelengths. The radiance data from these wavelengths was used to deduce the ozone profile and the total column ozone. In February 1987, there was an instrument malfunction. The purpose of this paper is to describe the malfunction, to determine the effect of the malfunction on the data quality, and if possible, to correct for the effects of the malfunction on the data from the SBUV instrument.

Gleason, James F.↗
NASA NTRS2004

Discoveries about Tropospheric Ozone Pollution from Satellite and Sounding

We have been producing near-real time tropospheric ozone satellite maps from the TOMS (Total Ozone Mapping Spectrometer) sensor since 1997. This is most readily done for the tropics, where the stratospheric and tropospheric ozone column amounts can be discriminated readily. Maps for 1996-2000 for the operational Earth-Probe instrument reside at: chttp://www.atmos.umd.edu/-trope>. Pollution in the tropics is influenced by biomass burning and by transport patterns that favor recirculation and in other cases reflect climate variability like the El-Nino-Southern Oscillation [Thompson et al., 2001]. Time permitting, examples of mid-latitude, intercontinental transport of ozone pollution sensed by TOMS will be shown. The satellite view of chemical-dynamical interactions in tropospheric ozone is not adequate to capture vertical variability. Thus, in 1998, NASA's Goddard Space Flight Center and a team of international sponsors established the SHADOZ (Southern Hemisphere ADditional OZonesondes) project to address the gap in tropical ozone soundings. SHADOZ augments launches and provides a public archive of ozonesonde data from twelve tropical stations at http://croc.gsfc.nasa.gov/shadoz. Further insights into the role of chemical and dynamical influences have emerged from the first 4-5 years of SHADOZ data (less than 2000 ozone profiles): (a) highly variable tropospheric ozone; (b) a zonal wave-one pattern in tropospheric column ozone; (c) convective variability affects tropospheric ozone over the Indian and Pacific Ocean; (d) a "tropical Atlantic Paradox" appears in December-January-February.

Thompson, Anne M.↗
NASA NTRS1989

Satellite/rocket ozone comparisons at Natal, Brazil

Comparisons are presented of satellite, rocket, and balloon ozone profiles near Natal, Brazil (5.9 deg S, 35.2 deg W). The low variability of stratospheric ozone at Natal during March and April of 1985 has allowed intercomparisons of reasonably large data sets, rather than a small number of paired satellite/in situ comparisons. There are sharp differences between the profile from the SBUV instrument on Nimbus 7 and the in situ measurements. These results support the conclusions of the NASA Ozone Trends Panel that there is an instrumental cause for the very large changes in upper stratospheric ozone seen by SBUV. Along with other comparisons, these results are being used in a reassessment of the SBUV instrument and its data reduction procedures. The agreement between the ozone profiles from the SAGE II instrument on the ERBS satellite and the rocket values is excellent over the full range of comparisons. Both SAGE II and ROCOZ-A must convert from altitude to pressure for intercomparisons with SME and with SBUV-type instruments. The conversion between pressure and altitude is as important as the ozone measurements, especially in the upper stratosphere where the scale height for ozone is approximately half that for pressure.

Barnes, Robert A.↗
NASA NTRS2019

Long-Term Ozone Variability and Trends from Reanalyses: Can It Be Done?

Stratospheric ozone concentrations have begun to show early signs of recovery following the implementation of the Montreal Protocol and its amendments as well as in response to decreasing upper-stratospheric temperatures. Secular trends in stratospheric ozone are modulated by considerable interannual variability and systematic changes in transport patterns that are expected under increasing concentrations of greenhouse gases, especially in the lower stratosphere. These factors necessitate the continued close monitoring of stratospheric ozone in upcoming decades, with a special focus on the lower stratosphere.As highly resolved data sets combining a plethora of observations with model simulations atmospheric reanalyses are, in principle, well suited for the task. All major reanalyses generate ozone output. However, significant spurious discontinuities that arise from step changes in the observing systems prevent a straightforward analysis of ozone trends and long-term variability. Building on our recent work, in this presentation we will demonstrate that trend detection is nonetheless possible using the ozone record from NASA's MERRA-2 (Modern-Era Retrospective Analysis for Research and Applications, Version 2) reanalysis bias-corrected using a chemistry model simulation as a transfer function. Next, we will outline several strategies to reduce artificial discontinuities in the ozone record in future NASA reanalyses. This discussion will be illustrated by an example of joint assimilation of bias-corrected ozone profiles from the Microwave Limb Sounder (MLS) on the Aura satellite (2004 to present) and the Ozone Mapping Profiler Suite Limb Profiler (OMPS-LP) sensors that are expected to operate on future NOAA platforms.

Wargan, Krzysztof↗
NASA NTRS2001

ECC Ozonesonde Reliability, Observations, and Comparisons with Satellite Ozone Instruments

Electrochemical Concentration Cell (ECC) ozone instruments depend on the quality of care exercised in their pre-flight preparation. The ozone-measuring project conducted at Goddard Space Flight Center's Wallops Flight Facility uses a number of mechanisms designed to inspect the ECC for anomalies that may interfere with the reception of valid ozone profiles. Complete electronic testing of the instrument, individually and when coupled to its radiosonde has led to exceptional monitoring of ozone for detecting long-term atmospheric changes. A number of factors are considered when preparing an ECC instrument for flight. These basically are specific calibrations of pump efficiency, volumetric flow rate, temperature of the air entering the pump, and background current. The concentration of the potassium iodide solution is also important. Wallops is the only site using a UV photometer (Dasibi) to compare ECC ozone output at various concentrations of ozone that allows adjustment to be made to offsets that may appear in the balloon-borne instrument prior to release. All of the above procedures allow identification of potential problems before release of the ECC instrument. Procedures followed at Wallops also are employed in Brazil, and Ascension Island where NASA has cooperative agreements in place to obtain ozonesondes data. All ECC instruments are prepared 3-4 weeks prior to the day of observation. We will briefly describe the instrumental tests employed. These tests have included simultaneous dual observations to compare the effect of different solution concentrations, comparison of sensors of different manufacturers, and comparisons with surface- and space-based instrumentation such as the Dobson Spectrophotometer and satellites. Vertical profiles of ozone from Arctic, mid-latitudes, and Antarctica will be discussed. Although not unusual, the data reveals ozone structure that correlate well with typical atmospheric temperatures and possibly relative humidity. Finally, vertical ozone distribution, compared with remotely measured ozone from lidar and satellite, will be discussed. Specific comparisons between ECC and HALOE measurements, integrated ECC total ozone overburden with the EP-TOMS and the Dobson, as well as comparisons with lidar are discussed. Results show agreement and some disagreement between the in situ measurements of the ECC and the remote instruments. We postulate reasons for the differences, or biases, which in spite of the excellent ECC quality control during pre-flight preparation and data analysis processes, may be due to uncertainties in both measuring systems.

Schmidlin, F. J.↗
NASA NTRS1981

Quadrennial International Ozone Symposium, Boulder, CO, August 4-9, 1980, Proceedings. Volumes 1 & 2

Recent developments in observational techniques are examined, taking into account a review of some unresolved problems in the measurement/estimation of total ozone and the vertical ozone profile, the sensitivity of Dobson total ozone estimations to wavelength band calibration uncertainties, errors in Dobson total measurements arising from aerosol attenuation, and optical stop and focussing effects in the Dobson instrument. Other subjects considered are related to total ozone observations, tropospheric ozone, upper air ozone observations, observations of trace gases in the atmosphere, ozone photochemistry and directly related photochemical models, the interaction of ozone and atmospheric circulation, ozone effects on climate, and solar activity and ozone variations. Programs and recommendations involving ozone theory and observations are also discussed, giving attention to current problems of ozone chemistry, the upper atmosphere research satellite program, a French contribution to ozone related studies, and ozone and the middle atmosphere program.

London, J.↗
NASA NTRS1982

Space observations of aerosols and ozone; Proceedings of the Topical Meeting, Ottawa, Canada, May 16-June 2, 1982

The measurement of aerosols from space is discussed, taking into account the role of aerosols in climate, instrumentation and further measurement systems, retrieval procedures, measurements and observations, ground truth measurements, and effects on remote sensing and on climate. Aspects of ozone variability in the middle atmosphere are explored, giving attention to the quasi-biennial oscillation in equatorial stratospheric temperatures and total ozone, global pictures on the ozone field from high altitudes from DE-1, measurements of atmospheric ozone from aircraft and from balloons, a mesospheric ozone profile at sunset, periodic and aperiodic ozone variations in the middle and upper stratosphere, solar eclipse induced variations in mesospheric ozone concentrations, and solar UV and ozone balloon measurements. The determination of aerosol optical depth is considered along with a method for estimating cross radiance.

Mccormick, M. P.↗
NASA NTRS2005

Assimilation of MLS and OMI Ozone Data

Ozone data from Aura Microwave Limb Sounder (MLS) and Ozone Monitoring Instrument (OMI) were assimilated into the ozone model at NASA's Global Modeling and Assimilation Office (GMAO). This assimilation produces ozone fields that are superior to those from the operational GMAO assimilation of Solar Backscatter Ultraviolet (SBUV/2) instrument data. Assimilation of Aura data improves the representation of the "ozone hole" and the agreement with independent Stratospheric Aerosol and Gas Experiment (SAGE) III and ozone sonde data. Ozone in the lower stratosphere is captured better: mean state, vertical gradients, spatial and temporal variability are all improved. Inclusion of OMI and MLS data together, or separately, in the assimilation system provides a way of checking how consistent OMI and MLS data are with each other, and with the ozone model. We found that differences between OMI total ozone column data and model forecasts decrease after MLS data are assimilated. This indicates that MLS stratospheric ozone profiles are consistent with OMI total ozone columns. The evaluation of error characteristics of OMI and MLS ozone will continue as data from newer versions of retrievals becomes available. We report on the initial step in obtaining global assimilated ozone fields that combine measurements from different Aura instruments, the ozone model at the GMAO, and their respective error characteristics. We plan to use assimilated ozone fields in estimation of tropospheric ozone. We also plan to investigate impacts of assimilated ozone fields on numerical weather prediction through their use in radiative models and in the assimilation of infrared nadir radiance data from NASA's Advanced Infrared Sounder (AIRS).

Stajner, I.↗
NASA NTRS2006

Tropospheric and stratospheric ozone from assimilation of Aura data

Ozone is an atmospheric trace gas with multiple impacts on the environment. Global ozone fields are needed for air quality predictions, estimation of the ultraviolet radiation reaching the surface, climate-radiation studies, and may also have an impact on longer-term weather predictions. We estimate global ozone fields in the stratosphere and troposphere by combining the data from EOS Aura satellite with an ozone model using data assimilation. Ozone exhibits a large temporal variability in the lower stratosphere. Our previous work showed that assimilation of satellite data from limb-sounding geometry helps constrain ozone profiles in that region. We assimilated ozone data from the Aura Microwave Limb Sounder (MLS) and the Ozone Monitoring Instrument (OMI) into the ozone system at NASA's Global Modeling and Assimilation Office (GMAO). Ozone is transported within a general circulation model (GCM) which includes parameterizations for stratospheric photochemistry, tropospheric chemistry, and a simple scheme for heterogeneous ozone loss. The focus of this study is on the representation of ozone in the lower stratosphere and tropospheric ozone columns. We plan to extend studies of tropospheric ozone distribution through assimilation of ozone data from the Tropospheric Emission Spectrometer (TES). Comparisons with ozone sondes and occultation data show that assimilation of Aura data reproduces ozone gradients and variability in the lower stratosphere well. We proceed by separating the contributions to temporal changes in the ozone field into those that are due to the model and those that are due to the assimilation of Aura data. The impacts of Aura data are illustrated and their role in the representation of ozone variability in the lower stratosphere and troposphere is shown.

Stajner, I.↗
NASA NTRS2014

Postlaunch Performance of the Suomi National Polar-Orbiting Partnership Ozone Mapping and Profiler Suite (OMPS) Nadir Sensors

The prelaunch specifications for nadir sensors of the Ozone Mapping and Profiler Suite (OMPS) were designed to ensure that measurements from them could be used to retrieve total column ozone and nadir ozone profile information both for operational use and for use in long-term ozone data records. In this paper, we will show results from our extensive analysis of the performance of the nadir mapper (NM) and nadir profiler (NP) sensors during the first year and a half of OMPS nadir operations. In most cases, we determined that both sensors meet or exceed their prelaunch specifications. Normalized radiance (radiance divided by irradiance) measurements have been determined to be well within their 2% specification for both sensors. In the case of stray light, the NM sensor is within its 2% specification for all but the shortest wavelengths, while the NP sensor is within its 2% specification for all but the longest wavelengths. Artifacts that negatively impacted the sensor calibration due to diffuser features were reduced to less than 1% through changes made in the solar calibration sequence. Preliminary analysis of the disagreement between measurements made by the NM and NP sensors in the region where their wavelengths overlap indicates that it is due to shifts in the shared dichroic filter after launch and that it can be corrected. In general, our analysis indicates that both the NM and NP sensors are performing well, that they are stable, and that any deviations from nominal performance can be well characterized and corrected.

ozone↗
NASA NTRS2019

Trend Quality Ozone from NPP OMPS: The Version 2 Processing

A version 2 processing of data from two ozone monitoring instruments on Suomi NPP, the OMPS nadir ozone mapper and the OMPS nadir ozone profiler, has now been completed. The previously released data were useful for many purposes but were not suitable for use in ozone trend analysis. In this processing, instrument artifacts have been identified and corrected, an improved scattered light correction and wavelength registration have been applied, and soft calibration techniques were implemented to produce a calibration consistent with data from the series of SBUV/2 instruments. The result is a high-quality ozone time series suitable for trend analysis. Total column ozone data from the OMPS nadir mapper now agree with data from the SBUV/2 instrument on NOAA 19 with a zonal average bias of −0.2 % over the 60° S to 60° N latitude zone. Differences are somewhat larger between OMPS nadir profiler and N19 total column ozone, with an average difference of −1.1 % over the 60° S to 60° N latitude zone and a residual seasonal variation of about 2 % at latitudes higher than about 50°. For the profile retrieval, zonal average ozone in the upper stratosphere (between 2.5 and 4 hPa) agrees with that from NOAA 19 within ±3 % and an average bias of −1.1 %. In the lower stratosphere (between 25 and 40 hPa) agreement is within ±3 % with an average bias of +1.1 %. Tropospheric ozone produced by subtracting stratospheric ozone measured by the OMPS limb profiler from total column ozone measured by the nadir mapper is consistent with tropospheric ozone produced by subtracting stratospheric ozone from MLS from total ozone from the OMI instrument on Aura. The agreement of tropospheric ozone is within 10 % in most locations.

OMPS nadir ozone mapper↗
NASA NTRS1994

Estimated SAGE II ozone mixing ratios in early 1993 and comparisons with Stratospheric Photochemistry, Aerosols and Dynamic Expedition measurements

An empirical time-series model for estimating ozone mixing ratios based on Stratospheric Aerosols and Gas Experiment II (SAGE II) monthly mean ozone data for the period October 1984 through June 1991 has been developed. The modeling results for ozone mixing ratios in the 10- to 30- km region in early months of 1993 are presented. In situ ozone profiles obtained by a dual-beam UV-absorption ozone photometer during the Stratospheric Photochemistry, Aerosols and Dynamics Expedition (SPADE) campaign, May 1-14, 1993, are compared with the model results. With the exception of two profiles at altitudes below 16 km, ozone mixing ratios derived by the model and measured by the ozone photometer are in relatively good agreement within their individual uncertainties. The identified discrepancies in the two profiles are discussed.

Yue, G. K.↗
NASA NTRS1994

Ozone, aerosols and polar stratospheric clouds measurements during the EASOE Campaign

Preliminary results are presented of observations obtained during the EASOE campaign, with an airborne backscatter lidar and a ground-based DIAL ozone lidar system. Although the main signature observed on the lidar signals was due to the Pinatubo cloud which erupted in June 1991, distinct PSC events were detected on several occasions by the airborne lidar often in relation with orographic wave activity over the norvegian mountains. The ozone profiles obtained in Sodankyla with the ground based lidar are locally perturbed by the presence of the volcanic cloud. After a first correction of the aerosols effect, they present however a reasonably good agreement with the ozone sondes profiles performed on the same site.

Godin, S.↗