Engineering Papers⌕ Search

Engineering topics

David Flittner

Publications and source records attributed to David Flittner.

At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2022

SAGE III/ISS Ozone and NO2 Validation Using Diurnal Scaling Factors

We developed a set of solar zenith angle, latitude- and altitude-dependent scaling factors to account for the diurnal variability in ozone (O3) and nitrogen dioxide (NO2) when comparing Stratospheric Aerosol and Gas Experiment (SAGE) III/ISS observations to observations from other times of day. The scaling factors are calculated as a function of solar zenith angle from the four-dimensional output of a global atmospheric chemistry model simulation of 2017–2020 that shows good agreement with observed vertical profiles. Using a global atmospheric chemistry model allows us to account for both chemically and dynamically driven variability. Both year-specific scale factors and a multi-year monthly climatology are available to decrease the uncertainty in inter-instrument comparisons and allow consistent comparisons between observations from different times of day. We describe the variability in the diurnal scale factors as a function of space and time. The quasi-biennial oscillation (QBO) appears to be a contributing factor to interannual variability in the NO2 scaling factors, leading to differences between years that switch sign with altitude. We show that application of these scaling factors improves the comparison between SAGE III/ISS and OSIRIS NO2 and between SAGE III/ISS and OMPS LP, OSIRIS, and ACE-FTS O3 observations. The comparisons between SAGE III/ISS O3 for sunrise or sunset vs. Microwave Limb Sounder (MLS) daytime or nighttime observations are also more consistent when we apply the diurnal scaling factors. There is good agreement between SAGE III/ISS V5.2 ozone and correlative measurements, with differences within 5 % between 20 and 50 km when corrected for diurnal variability. Similarly, the SAGE III/ISS V5.2 NO2 agreement with correlative measurement is mostly within 10 %. While the scale factors were designed for use with SAGE III/ISS observations, they can easily be applied to other observation intercomparisons as well.

Sarah A. Strode↗
NASA NTRS2020

Validation of SAGE III/ISS Solar Ozone Data with Correlative Satellite and Ground Based Measurements

The Stratospheric Aerosol and Gas Experiment III on the International Space Station (SAGE III/ISS) was launched on February 19, 2017 and began routine operation in June 2017. The first two years of SAGE III/ISS (v5.1) solar ozone data were evaluated by using correlative satellite and ground-based measurements. Among the three (MES, AO3, and MLR) SAGE III/ISS solar ozone products, AO3 ozone shows the best accuracy and precision, with mean biases less than 5% for altitudes ~15–55 km in the mid-latitudes and ~20–55 km in the tropics. In the lower stratosphere and upper troposphere, AO3 ozone shows high biases that increase with decreasing altitudes and reach ~10% near the tropopause. Preliminary studies indicate that those high biases primarily result from the contributions of the oxygen dimer (O4) not being appropriately removed within the ozone channel. The precision of AO3 ozone is estimated to be ~3% for altitudes between 20 and 40 km. It degrades to ~10–15% in the lower mesosphere (~55 km), and ~20–30% near the tropopause. There could be an altitude registration error of ~100 meter in the SAGE III/ISS auxiliary temperature and pressure profiles. This, however, does not affect retrieved ozone profiles in native number density on geometric altitude coordinates. In the upper stratosphere and lower mesosphere (~40–55 km) the SAGE III/ISS (and SAGE II) sunset ozone values are systematically higher than sunrise data by ~5–8% which are almost twice larger than what observed by other satellites or model predictions. This feature needs further study.

H J Wang↗
NASA NTRS2019

TPSAS-NF1676L-32936-DND

The Stratospheric Aerosol and Gas Experiment III (SAGE III) instrument, installed on the International Space Station (ISS), has completed over a year of data collection and production of science data products. The SAGE III/ISS is a solar and lunar occultation instrument, scanning the light from the sun and moon, through the limb of the Earth’s atmosphere. It was launched in February 2017 and provides data from June 2017 to the present. It continues SAGE's legacy of ozone, aerosol and water vapor profile measurements and extends the lengthy records for monitoring constituents important for understanding stratospheric ozone trends. This presentation shows the preliminary validation results of comparing SAGE III/ISS ozone and water vapor vertical profiles with those of NOAA ESRL/GMD and NIWA mission-funded ozonesondes and frost point hygrometers, and comparisons with other correlative data.

Susan Kizer↗
NASA NTRS2018

TPSAS-NF1676L-30150-DND

Validation of science data products from the Stratospheric Aerosol and Gas Experiment (SAGE) III, installed on the International Space Station (ISS) in March 2017, requires intercomparison with validated data sources. The SAGE III/ISS mission is actively utilizing in-situ profile measurements from balloon packages, consisting of a standard meteorological radiosonde, ozonesonde, and frost-point hygrometer, that were launched coincident with SAGE III/ISS overpass opportunities. Some packages have included an aerosol sonde. This provides regional correlations of ozone, water vapor and aerosol extinction between the in-situ measurement data and the SAGE III/ISS profile products. In addition, ground-based LIDAR measurements and aircraft-based measurements of ozone, water vapor, aerosol extinction and nitrogen dioxide will provide additional validation data for correlation with the SAGE III/ISS data products. Initial results of the mission directed validation program will be presented. When possible, operation and launch times were modified to improve the temporal and spatial coincidence between the measurements. Results and progress utilizing LIDAR and balloon-borne aerosol observations are discussed herein, while intercomparisons that make use of ozone sondes is are presented in the companion poster by Kizer et al.

Travis Knepp↗
NASA NTRSDate not supplied

TPSAS-NF1676L-32505-DND

The Stratospheric Aerosol and Gas Experiment III (SAGE III) instrument, installed on the International Space Station (ISS), has completed over a year of data collection and production of science data products, including the newly released version 5.1 data product. The SAGE III/ISS is a solar and lunar occultation instrument, scanning the light from the sun and moon, through the limb (edge) of the Earth's atmosphere. It was launched in February 2017 and provides data from June 2017 to the present. It continues SAGE's legacy of ozone, aerosol and water vapor profile measurements and extends the lengthy records for monitoring constituents important for understanding stratospheric ozone trends. This presentation shows the preliminary validation results of comparing SAGE III/ISS ozone vertical profiles with those of mission funded ozone sondes, associated lidar, and comparisons with other correlative data.

Susan Kizer↗
NASA NTRSDate not supplied

TPSAS-NF1676L-29194-DND

The Stratospheric Aerosol and Gas Experiment (SAGE) III instrument was deployed on the International Space Station (ISS) in early March 2017. SAGE III/ISS is the latest in the NASA lineage of solar occultation satellite instruments designed to monitor the vertical distribution of aerosol, ozone and other trace gases in the upper atmosphere. Originally built in the early 2000s, the SAGE III/ISS instrument required extensive testing and refurbishment prior to deliver to ISS, including the replacement of the neutral density filter that has been associated with some instrument response issues during the METEOR/3M mission. In particular, METEOR/3M measurements of the oxygen A-band absorption feature near 762 nm that were to be utilized to retrieve profiles of temperature and pressure were adversely affected by this instrument issue. Preliminary examination of the SAGE III/ISS oxygen A-band spectra indicate that the measurements are of higher fidelity than from the METEOR/3M instrument, which may permit successful retrieval of science quality temperature and pressure products. In this paper, we will provide an overview of the temperature and pressure retrieval algorithm, present preliminary analyses of the SAGE III/ISS oxygen A-band measurements, and an initial assessment of the quality of the temperature and pressure retrievals.

Michael Pitts↗
NASA NTRSDate not supplied

Stratospheric Aerosol and Gas Experiment III on the International Space Station(SAGE III/ISS) Validation of Three Years of Ozone and Water Vapor Data

The Stratospheric Aerosol and Gas Experiment III (SAGE III) instrument installed on the International Space Station (ISS) has completed three years of data collection and production of science data products. The SAGE III/ISS is a solar and lunar occultation instrument that scans the light from the Sun and Moon through the limb of the Earth’s atmosphere to produce vertical profiles of aerosol, ozone, water vapor, and other trace gases. It continues the legacy of previous SAGE instruments dating back to the 1970s to provide data continuity of stratospheric constituents critical for assessing trends in the ozone layer. This presentation shows the validation results of comparing SAGE III/ISS ozone and water vapor vertical profiles with those of in situ and satellite data.

SAGE III ISS ozone water vapor validation↗
NASA NTRSDate not supplied

Stratospheric Aerosol and Gas Experiment III on the International Space Station (SAGE III/ISS) Validation of Ozone and Water Vapor Data

The Stratospheric Aerosol and Gas Experiment III (SAGE III) instrument installed on the International Space Station (ISS) has completed four years of data collection and production of science data products. The SAGE III/ISS is a solar and lunar occultation instrument that scans the light from the Sun and Moon through the limb of the Earth’s atmosphere to produce vertical profiles of aerosol, ozone, water vapor, and other trace gases. It continues the legacy of previous SAGE instruments dating back to the 1970s to provide data continuity of stratospheric constituents critical for assessing trends in the ozone layer. Recently, the latest version 5.2 data product has been released to the public. This presentation shows the validation results of comparing v5.2 SAGE III/ISS ozone and water vapor vertical profiles with those of in situ and satellite data.

SAGE Stratosphere Stratospheric Mesospheric Ozone ↗
NASA NTRSDate not supplied

Stratospheric Aerosol and Gas Experiment on the International Space Station (SAGE III/ISS): Continuing the Legacy of SAGE Data Products

The Stratospheric Aerosol and Gas Experiment III (SAGE III) instrument installed on the International Space Station (ISS) has completed almost half of a decade of data collection and production of science data products. The SAGE III/ISS is a solar and lunar occultation instrument that scans the light from the Sun and Moon through the limb of the Earth’s atmosphere to produce vertical profiles of aerosol, ozone, water vapor, and other trace gases. It continues the legacy of previous SAGE instruments dating back to the 1970s to provide data continuity of stratospheric constituents critical for assessing trends in the ozone layer. This presentation shows how SAGE III/ISS aerosol and gas vertical profiles continue to benefit a worldwide database of in situ and satellite data for climate observation.

Susan Kizer↗
NASA NTRSDate not supplied

SAGE III/ISS v5.3 Level 2 Data Product Changes and Improvements

The Stratospheric Aerosol and Gas Experiment on the International Space Station (SAGE III/ISS) is an occultation instrument that acquires measurements of aerosols and gases within the Earth’s stratosphere and upper troposphere. SAGE III/ISS provides level 2 solar species products for aerosol extinction (9 channels), nitrogen dioxide (NO2), ozone (O3), and water vapor (H2O). The level 2 products currently provide three O3 profiles based on differing retrievals. The first O3 profile is based on measurements at short wavelengths within the Hartley-Huggins band (MesO3), the second O3 profile is based on measurements made at visible wavelengths within the Chappius band (MLR O3), and the final profile is found using a more SAGE II like approach (AO3). The SAGE III/ISS also provides level 2 lunar species products for ozone (O3), nitrogen dioxide (NO2), and nitrogen trioxide (NO3). Version 5.3 of the SAGE III/ISS retrieval algorithm introduces improvements that affect the level 2 data products. The largest change to the solar algorithm is the implementation of disturbance monitoring package (DMP) corrections to improve pointing accuracy. The DMP is comprised of a miniature inertial measurement unit that measures rotation in inertial space using ring laser gyroscopes oriented about three orthogonal axes which can be used to correct pointing errors caused by mechanical disturbances. A major change common to solar and lunar algorithms is meteorological input from the coarser 42 level Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) model data to the 72 level MERRA-2 model data. The final major change involves improving the automated quality assurance (QA) algorithm to recover events that were withheld from the public release because differences between the AO3 and MLR O3 for some events after the eruption of Tonga–Hunga Haʻapai. Other changes for v5.3 include minor bug fixes as well as restoration of some data quality flags that were removed in v5.21. This presentation presents the impacts of these changes as well as overall observations of interest from v5.3 level 2 data products.

Carter Hulsey↗
NASA NTRSDate not supplied

Stratospheric Water Vapor Observations From the International Space Station By the Stratospheric Aerosol and Gas Experiment III (Sage III/ISS)

The Stratospheric Aerosol and Gas Experiment III has routinely observed the upper atmosphere from the International Space Station (SAGE III/ISS) since June 2017. An important greenhouse gas and molecule affecting chemistry cycles, water vapor is among the vertical profiles of trace gases measured by SAGE III/ISS. This makes SAGE III/ISS the youngest of the current fleet of space-based instruments capable of measuring the vertical distribution of stratospheric water vapor (SWV). The SWV record is mature, a candidate for multi-instrument datasets, e.g. Stratospheric Water and Ozone Satellite Homogenized (SWOOSH) dataset, and shows promise within the GEOS Constituent Data Assimilation System. This presentation reviews the variations in SWV observed by SAGE III/ISS over the past half-decade. Variations highlighted include phase changes of the Quasi-biennial Oscillation (QBO), seasonal and monsoonal moisture patterns, and terrestrial events such as the recent January 2022 Hunga Tonga eruption that perturbed the SWV in spectacular fashion.

stratospheric water vapor↗
NASA NTRSDate not supplied

SAGE III/ISS v5.3 Level 2 Data Product Changes and Improvements

The Stratospheric Aerosol and Gas Experiment on the International Space Station (SAGE III/ISS) is an occultation instrument that acquires measurements of aerosols and gases within the Earth’s stratosphere and upper troposphere. SAGE III/ISS provides level 2 solar species products for aerosol extinction (9 channels), nitrogen dioxide (NO2), ozone (O3), and water vapor (H2O). The level 2 products currently provide three O3 profiles based on differing retrievals. The first O3 profile is based on measurements at short wavelengths within the Hartley-Huggins band (MesO3), the second O3 profile is based on measurements made at visible wavelengths within the Chappius band (MLR O3), and the final profile is found using a more SAGE II like approach (AO3). The SAGE III/ISS also provides level 2 lunar species products for ozone (O3), nitrogen dioxide (NO2), and nitrogen trioxide (NO3). Version 5.3 of the SAGE III/ISS retrieval algorithm introduces improvements that affect the level 2 data products. The largest change to the solar algorithm is the implementation of disturbance monitoring package (DMP) corrections to improve pointing accuracy. The DMP is comprised of a miniature inertial measurement unit that measures rotation in inertial space using ring laser gyroscopes oriented about three orthogonal axes which can be used to correct pointing errors caused by mechanical disturbances. A major change common to solar and lunar algorithms is meteorological input from the coarser 42 level Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) model data to the 72 level MERRA-2 model data. The final major change involves improving the automated quality assurance (QA) algorithm to recover events that were withheld from the public release because differences between the AO3 and MLR O3 for some events after the eruption of Tonga–Hunga Haʻapai. Other changes for v5.3 include minor bug fixes as well as restoration of some data quality flags that were removed in v5.21. This presentation presents the impacts of these changes as well as overall observations of interest from v5.3 level 2 data products.

Carter Hulsey↗