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Your search keyword '"Damadeo, R. P."' showing total 8 results
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8 results on '"Damadeo, R. P."'

1. Reevaluation of Stratospheric Ozone Trends From SAGE II Data Using a Simultaneous Temporal and Spatial Analysis

Author

Damadeo, R. P, Zawodny, J. M, and Thomason, L. W

Subjects
Geophysics, Earth Resources And Remote Sensing
Abstract

This paper details a new method of regression for sparsely sampled data sets for use with time-series analysis, in particular the Stratospheric Aerosol and Gas Experiment (SAGE) II ozone data set. Non-uniform spatial, temporal, and diurnal sampling present in the data set result in biased values for the long-term trend if not accounted for. This new method is performed close to the native resolution of measurements and is a simultaneous temporal and spatial analysis that accounts for potential diurnal ozone variation. Results show biases, introduced by the way data is prepared for use with traditional methods, can be as high as 10%. Derived long-term changes show declines in ozone similar to other studies but very different trends in the presumed recovery period, with differences up to 2% per decade. The regression model allows for a variable turnaround time and reveals a hemispheric asymmetry in derived trends in the middle to upper stratosphere. Similar methodology is also applied to SAGE II aerosol optical depth data to create a new volcanic proxy that covers the SAGE II mission period. Ultimately this technique may be extensible towards the inclusion of multiple data sets without the need for homogenization.

Published
2014

2. SAGE Version 7.0 Algorithm: Application to SAGE II

Author

Damadeo, R. P, Zawodny, J. M, Thomason, L. W, and Iyer, N

Subjects
Computer Programming And Software, Earth Resources And Remote Sensing
Abstract

This paper details the Stratospheric Aerosol and Gas Experiments (SAGE) version 7.0 algorithm and how it is applied to SAGE II. Changes made between the previous (v6.2) and current (v7.0) versions are described and their impacts on the data products explained for both coincident event comparisons and time-series analysis. Users of the data will notice a general improvement in all of the SAGE II data products, which are now in better agreement with more modern data sets (e.g. SAGE III) and more robust for use with trend studies.

Published
2013
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3. On the ambiguous nature of the 11 year solar cycle signal in upper stratospheric ozone

Author

Dhomse, S. S., Chipperfield, M. P., Damadeo, R. P., Zawodny, J. M., Ball, W. T., Feng, W., Hossaini, R., Mann, G. W., and Haigh, J. D.

Subjects
SAGE II, Science & Technology, QUASI-BIENNIAL OSCILLATION, solar signal, MT. PINATUBO ERUPTION, CLIMATE MODEL, CIRCULATION, Geology, modeling, SIMULATIONS, VARIABILITY, CHEMICAL-TRANSPORT MODEL, SPECTRAL IRRADIANCE, Physical Sciences, stratosphere, MD Multidisciplinary, Meteorology & Atmospheric Sciences, Geosciences, Multidisciplinary, VERSION
Abstract

Up to now our understanding of the 11 year ozone solar cycle signal (SCS) in the upper stratosphere has been largely based on the Stratospheric Aerosol and Gas Experiment (SAGE) II (v6.2) data record, which indicated a large positive signal which could not be reproduced by models, calling into question our understanding of the chemistry of the upper stratosphere. Here we present an analysis of new v7.0 SAGE II data which shows a smaller upper stratosphere ozone SCS, due to a more realistic ozone-temperature anticorrelation. New simulations from a state-of-art 3-D chemical transport model show a small SCS in the upper stratosphere, which is in agreement with SAGE v7.0 data and the shorter Halogen Occultation Experiment and Microwave Limb Sounder records. However, despite these improvements in the SAGE II data, there are still large uncertainties in current observational and meteorological reanalysis data sets, so accurate quantification of the influence of solar flux variability on the climate system remains an open scientific question.

Published
2016

4. On the ambiguous nature of the 11year solar cycle signal in upper stratospheric ozone

Author

Dhomse, S. S., Chipperfield, M. P., Damadeo, R. P., Zawodny, J. M., Ball, W. T., Feng, W., Hossaini, R., Mann, G. W., Haigh, J. D., Dhomse, S. S., Chipperfield, M. P., Damadeo, R. P., Zawodny, J. M., Ball, W. T., Feng, W., Hossaini, R., Mann, G. W., and Haigh, J. D.

Abstract

Up to now our understanding of the 11year ozone solar cycle signal (SCS) in the upper stratosphere has been largely based on the Stratospheric Aerosol and Gas Experiment (SAGE) II (v6.2) data record, which indicated a large positive signal which could not be reproduced by models, calling into question our understanding of the chemistry of the upper stratosphere. Here we present an analysis of new v7.0 SAGE II data which shows a smaller upper stratosphere ozone SCS, due to a more realistic ozone-temperature anticorrelation. New simulations from a state-of-art 3-D chemical transport model show a small SCS in the upper stratosphere, which is in agreement with SAGE v7.0 data and the shorter Halogen Occultation Experiment and Microwave Limb Sounder records. However, despite these improvements in the SAGE II data, there are still large uncertainties in current observational and meteorological reanalysis data sets, so accurate quantification of the influence of solar flux variability on the climate system remains an open scientific question.

Published
2016

8. Validation of SAGE III/ISS Solar Water Vapor Data With Correlative Satellite and Balloon‐Borne Measurements

Author

Davis, S. M., Damadeo, R., Flittner, D., Rosenlof, K. H., Park, M., Randel, W. J., Hall, E. G., Huber, D., Hurst, D. F., Jordan, A. F., Kizer, S., Millan, L. F., Selkirk, H., Taha, G., Walker, K. A., and Vömel, H.

Abstract

Since June 2017, the Stratospheric Aerosol and Gas Experiment III instrument on the International Space Station (SAGE III/ISS) has been providing vertical profiles of upper tropospheric to stratospheric water vapor (SWV) retrieved from solar occultation transmission measurements. The goal of this study is to evaluate the publicly released SAGE III/ISS beta version 5.1 WV retrieval through intercomparison with independent satellite‐ and balloon‐based measurements, and to present recommendations for SAGE III/ISS data quality screening criteria. Overall, we find that SAGE III/ISS provides high quality water vapor measurements. Low quality profiles are predominately due to retrieval instabilities in the upper stratosphere that cause step‐like changes in the profile, and aerosol/cloud‐related interferences (below ∼20 km). Above 35 km, the retrieved uncertainty and noise in the data rapidly grow with increasing altitude due to relatively low extinction signal from water vapor. Below the tropopause, retrieved uncertainty increases with decreasing altitude due to enhanced molecular scattering and aerosol extinction. After screening low‐quality data using the procedures described herein, SAGE III/ISS WV is shown to be in good agreement with independent satellite and balloon‐based measurements. From 20 to 40 km, SAGE III/ISS WV v5.1 data exhibit a bias of 0.0 to −0.5 ppmv (∼10%) relative to the independent data, depending on the instrument and altitude. Despite its status as a beta version, the level of SAGE III/ISS WV agreement with independent data is similar to previous SAGE instruments, and therefore the data are suitable for scientific studies of SWV. Measurements of water vapor (WV) in the stratosphere are important for understanding climate change. This study presents new measurements of SWV from an instrument aboard the International Space Station, and describes methods for filtering the data to retain only the highest quality profiles for scientific analysis. The new measurements compare well to existing satellite and scientific balloon measurements of SWV, and therefore will be of use for studying year‐to‐year and longer‐term changes in SWV. Water vapor data from the Stratospheric Aerosol and Gas Experiment on the International Space Station are assessedData screening procedures are described for removing anomalous data and data impacted by cloud interferenceWith appropriate filtering, the new data agree with other correlative measurements within ∼10% in the stratosphere Water vapor data from the Stratospheric Aerosol and Gas Experiment on the International Space Station are assessed Data screening procedures are described for removing anomalous data and data impacted by cloud interference With appropriate filtering, the new data agree with other correlative measurements within ∼10% in the stratosphere

Published
2021
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