Analysis of Observed Contamination Through SAGE III's First Year on Orbit

SAGE III is a payload on the International Space Station that conducts measurements of ozone and other atmospheric constituents through the use of a moderate resolution spectrometer with an operating wavelength range of 290 nm to 1550 nm. Because of the optically sensitive nature of the payload, a suite of eight Thermoelectric Quartz Crystal Microbalances (TQCMs) were included to monitor the operating environment. During the rst year of operation, the SAGE III TQCMs were instrumental in detecting several periods of higher contamination and localizing their sources. A clear window made from quartz crystal covers the instrument assembly's aperture. Under nominal operating conditions, this window is only open during science gathering activities. However, if the rates of contamination accumulation are detected to be above the background rate, the window will be kept closed during science gathering to protect the optically sensitive instrument mirror. An analysis of the signal transmissions through the window for the wavelengths of 290 nm to 1550 nm has been conducted to determine any possible degradation of the window and potential in uence on science data collected to date, and established a baseline for future analysis

Earth Science With the Stratospheric Aerosol and Gas Experiment III (SAGE III) on the International Space Station

The Stratospheric Aerosol and Gas Experiment (SAGE) III is the fourth generation of solar occultation instruments operated by NASA, the first coming under a different acronym, to investigate the Earth's upper atmosphere. Three flight-ready SAGE III instruments were built by Ball Aerospace in the late 1990s, with one launched aboard the former Russian Aviation and Space Agency (now known as Roskosmos) Meteor-3M platform on 10 December 2001 (continuing until the platform lost power in 2006). Another of the original instruments was manifested for the ISS in the 2004 time frame, but was delayed because of budgetary considerations. Fortunately, that SAGE III/ISS mission was restarted in 2009 with a major focus upon filling an anticipated gap in ozone and aerosol observation in the second half of this decade. Here we discuss the mission architecture, its implementation, and data that will be produced by SAGE III/ISS, including their expected accuracy and coverage. The 52-degree inclined orbit of the ISS is well-suited for solar occultation and provides near-global observations on a monthly basis with excellent coverage of low and mid-latitudes. This is similar to that of the SAGE II mission (1985-2005), whose data set has served the international atmospheric science community as a standard for stratospheric ozone and aerosol measurements. The nominal science products include vertical profiles of trace gases, such as ozone, nitrogen dioxide and water vapor, along with multi-wavelength aerosol extinction. Though in the visible portion of the spectrum the brightness of the Sun is one million times that of the full Moon, the SAGE III instrument is designed to cover this large dynamic range and also perform lunar occultations on a routine basis to augment the solar products. The standard lunar products were demonstrated during the SAGE III/M3M mission and include ozone, nitrogen dioxide & nitrogen trioxide. The operational flexibility of the SAGE III spectrometer accomplishes the main goal of producing ozone and aerosol extinction profiles, while allowing exploration of new possibilities for the occultation technique, such as night-time aerosol extinction profiles or other trace gases not measured by SAGE in the past

Atmospheric ozone and sulfur dioxide from satellite measurements of backscattered ultraviolet light.

An iterative method of estimating total atmospheric O₃ and SO₂ is developed for currently available satellite measurements of backscattered ultraviolet (uv) radiation. This method utilizes a direct inversion of the equation of radiative transfer by using a first order Taylor expansion of this equation with respect to a guessed combination of total O₃ and total SO₂. A new guess is made so as to minimize the difference between the measurements and theoretically calculated values. This method is able to model an atmosphere with molecular scattering or one with scattering by both molecules and particulates. A sensitivity analysis is presented and, in the case of a molecular atmosphere, the errors in retrieved total O₃ are on the order of 20% and for total SO₂ are 25%. Estimates can be performed for an atmosphere containing both molecular scatters and particulate scatters for scattering angles of 110°-150°. In the case of volcanic ash and SO₂ mixed within the stratospheric eruption cloud, retrieval errors for these angles are within the same range as those of the molecular only atmosphere if: the index of refraction of the ash is known to within a factor of 1.5 and the mean radius is also known to within a factor of 2. Application of this method to total ozone measuring spectrometer (TOMS) Nimbus 7 data for scans of a volcanic cloud show the total O₃ amount within the cloud to be noticeably lower than those of positions out of the cloud. This is consistent with the results of others

Deriving Vertical Profiles of Aerosol Sizes from TES

International audienc

Early validation of SAGEIII/ISS ozone and aerosol products by lidar and sondes measurements at Haute-Provence Observatory, France

International audienceVarious measurement techniques have been deployed for the monitoring of ozone and aerosols vertical distribution at Haute-Provence Observatory (OHP - 44°N, 6°E) within the Network for the Detection of Atmospheric Composition Changes (NDACC) since the 1980s. These techniques include two Differential Absorption (DIAL) lidars and balloon soundings for the measurements of tropospheric and stratospheric ozone profiles, and a backscatter lidar for the measurement of aerosols and temperature profiles. Aerosol extinction profiles are obtained at 532 nm. They can also be retrieved from the DIAL lidar signals at 355 nm. These measurements have been widely used in the past for trend studies and validation of satellite measurements, e.g. Hubert et al. (2016) and Khaykin et al. (2017). They are used in this study to evaluate the various ozone and aerosol extinction products of SAGEIII/ISS obtained in the vicinity of OHP since the beginning of instrument operation. References: Hubert Daan, et al., Ground-based assessment of the bias and long-term stability of fourteen limb and occultation ozone profile data records, Atmos. Meas. Tech., 9, 2497-2534, 2016 Khaykin Sergey, et al., Variability and evolution of the midlatitude stratospheric aerosol budget from 22 years of ground-based lidar and satellite observations. Atmospheric Chemistry and Physics, European Geosciences Union, 2017, 17 (3), pp.1829-184

Deriving Vertical Profiles of Aerosol Sizes from TES

International audienc

Deriving Vertical Profiles of Aerosol Sizes from TES

International audienc