Engineering topics

Robert P Damadeo

Publications and source records attributed to Robert P Damadeo.

4 records

NASA NTRS2021

Near-Global Variability of Stratospheric Water Vapor Observed by SAGE III/ISS

The Stratospheric Aerosol and Gas Experiment III instrument on the International Space Station (SAGE III/ISS) has been making high quality solar occultation measurements of stratospheric water vapor since June 2017. Here we evaluate the large-scale geophysical variability of the SAGE III/ISS water vapor measurements for the first 3 years of observations (2017–2020) as part of data validation for retrieval version 5.1 (v5.1). Detailed comparisons of SAGE III/ISS v5.1 with the Aura Microwave Limb Sounder (MLS) version 5 retrievals show overall excellent agreement in terms of seasonal mean structure and large-scale variability. SAGE III/ISS data capture the well-known seasonal variations in water vapor including the vertically propagating “tape recorder” in the tropics and lower stratospheric maxima linked to the NH summer monsoons. The high vertical resolution (∼2 km) measurements from SAGE III/ISS demonstrate contributions of the monsoons to the wet phase of “tape recorder” during the Northern Hemisphere (NH) summer. Interannual variations over the short data record are also consistent between SAGE III/ISS and MLS in the stratosphere between 16 and 30 km. We furthermore evaluate large-scale variations in relative humidity (RH) derived from the high vertical resolution SAGE III/ISS water vapor measurements, highlighting the detailed seasonal behavior and links to thermal structure near the tropical tropopause. Spatial distributions of RH at the cold point tropopause (CPT) show a close link between high RH and the minimum CPT temperature in both the NH winter and summer, consistent with temperature control of water vapor near the tropopause.

water vapor↗

NASA NTRSDate not supplied

TPSAS-NF1676L-17943-DND

SAGE II used the solar occultation technique to measure atmospheric ozone for 21 years between 1984 and 2005 and has continued to play a key role in numerous international assessments. Traditionally, the determination of trends in ozone using SAGE II data has been done via time series analysis of monthly mean data within specific latitude bands. However, given the sparse sampling of SAGE II data, this will introduce temporal and/or spatial biases, particularly in the period after late 2000 when the instrument operated at half-duty cycle. Herein we present a new method for performing time series analysis of unevenly sampled data (in particular SAGE II); namely, we utilize the daily mean data and perform a simultaneous temporal and spatial analysis, making use of a Fourier series to constrain latitudinal variation. This methodology is applied to both the previous (v6.2) and current (v7.0) versions of the SAGE II data. Results are discussed that show the improvements to the data between versions 6.2 and 7.0 that make time series analysis produce reduced residuals as well as the preliminary results of the time series itself, which reveal some of the limitations in currently used proxies for the regression.

Robert P Damadeo↗

NASA NTRSDate not supplied

SAGE III on ISS: Mission Update and Science Milestone Results and Future Plans

The Stratospheric Aerosol and Gas Experiment III on the International Space Station (SAGE III/ISS) has been collecting data on the stratosphere almost continuously for 4 years since the first light milestone was achieved on March 17, 2017. In that time, the SAGE III/ISS data products have withstood robust assessments both internal and external, using comparisons to data sets both in-situ and spaceborne, and incorporated improvements into the retrieval algorithm and the science data products themselves. With the new v5.2 release of the SAGE III/ISS science data product algorithm, improvements made to the aerosol and water vapor products have produced better correlations with both MLS and balloonsonde data. At this 4-year milestone, we will look back on the last 4 years of data collection highlighting SAGE III/ISS ozone and aerosol data from 2017-2020 in a 6-minute video highlighting the SAGE III mission. An overview of mission operations and the challenges of operating a science mission on the ISS will highlight lessons learned and the mission science objectives completed during the first three years of the mission. The future goals for the SAGE III/ISS mission, as we continue operations and science collection, will round out the presentation.

Marilee M Roell↗

NASA NTRSDate not supplied

SAGE III/ISS Data Product Improvements

In 2024 the Stratospheric Aerosol and Gas Experiment on the International Space Station (SAGE III/ISS) entered its eighth year of operations. Using a CCD spectrometer to observe solar and lunar occultations through Earth’s limb, the mission has retrieved tens of thousands of vertical profiles for ozone, aerosol, water vapor, and nitrogen dioxide. Retrieval algorithms are constantly under development to enhance these products. The next product version will improve upon previous versions by addressing problems with the aerosol extinction spectrum and recovering hundreds of profiles impeded by the recent proliferation of sunspots. Users of SAGE III/ISS data can also expect improvements to uncertainty estimates and a continued expansion of ancillary products.

Robert Manion↗