A critical analysis of Stratospheric Aerosol and Gas Experiment ozone trends

1996 ◽  
Vol 101 (D7) ◽  
pp. 12495-12514 ◽  
Author(s):  
H. J. Wang ◽  
D. M. Cunnold ◽  
X. Bao
Keyword(s):  
Critical Analysis ◽  
Stratospheric Aerosol ◽  
Ozone Trends

scholarly journals Characterization of Odin-OSIRIS ozone profiles with the SAGE II dataset

2013 ◽  
Vol 6 (5) ◽  
pp. 1447-1459 ◽  
Author(s):  
C. Adams ◽  
A. E. Bourassa ◽  
A. F. Bathgate ◽  
C. A. McLinden ◽  
N. D. Lloyd ◽  
...  
Keyword(s):  
Infrared Imaging ◽  
Imaging System ◽  
Correlation Coefficients ◽  
Relative Difference ◽  
Stratospheric Aerosol ◽  
High Latitudes ◽  
Crossing Time ◽  
Ozone Trends ◽  
Relative Differences

Abstract. The Optical Spectrograph and InfraRed Imaging System (OSIRIS) on board the Odin spacecraft has been taking limb-scattered measurements of ozone number density profiles from 2001–present. The Stratospheric Aerosol and Gas Experiment II (SAGE II) took solar occultation measurements of ozone number densities from 1984–2005 and has been used in many studies of long-term ozone trends. We present the characterization of OSIRIS SaskMART v5.0× against the new SAGE II v7.00 ozone profiles for 2001–2005, the period over which these two missions had overlap. This information can be used to merge OSIRIS with SAGE II into a single ozone record from 1984 to the present, if other satellite ozone measurements are included to account for gaps in the OSIRIS dataset in the winter hemisphere. Coincident measurement pairs were selected for ±1 h, ±1° latitude, and ±500 km. The absolute value of the resulting mean relative difference profile is <5% for 13.5–54.5 km and <3% for 24.5–53.5 km. Correlation coefficients R > 0.9 were calculated for 13.5–49.5 km, demonstrating excellent overall agreement between the two datasets. Coincidence criteria were relaxed to maximize the number of measurement pairs and the conditions under which measurements were taken. With the broad coincidence criteria, good agreement (< 5%) was observed under most conditions for 20.5–40.5 km. However, mean relative differences do exceed 5% for several cases. Above 50 km, differences between OSIRIS and SAGE II are partly attributed to the diurnal variation of ozone. OSIRIS data are biased high compared with SAGE II at 22.5 km, particularly at high latitudes. Dynamical coincidence criteria, using derived meteorological products, were also tested and yielded similar overall results, with slight improvements to the correlation at high latitudes. The OSIRIS optics temperature is low (<16 °C) during May–July, when the satellite enters the Earth's shadow for part of its orbit. During this period, OSIRIS measurements are biased low by 5–12% for 27.5–38.5 km. Biases between OSIRIS ascending node (northward equatorial crossing time ~18:00 LT – local time) and descending node (southward equatorial crossing time ~06:00 LT) measurements are also noted under some conditions. This work demonstrates that OSIRIS and SAGE II have excellent overall agreement and characterizes the biases between these datasets.

scholarly journals Drift corrected Odin-OSIRIS ozone product: algorithm and updated stratospheric ozone trends

2017 ◽  
Author(s):  
Adam E. Bourassa ◽  
Chris Z. Roth ◽  
Daniel J. Zawada ◽  
Landon A. Rieger ◽  
Chris A. McLinden ◽  
...  
Keyword(s):  
Stratospheric Ozone ◽  
Stratospheric Aerosol ◽  
Retrieval Algorithm ◽  
Number Density ◽  
Short Term ◽  
Time Period ◽  
Infrared Imager ◽  
Ozone Profile ◽  
Ozone Trends

Abstract. A small, long-term drift in the Optical Spectrograph and Infrared Imager System (OSIRIS) stratospheric ozone product, manifested mostly since 2012, is quantified and attributed to a changing bias in the limb pointing knowledge of the instrument. A correction to this pointing drift using a predictable shape in the measured limb radiance profile is implemented and applied within the OSIRIS retrieval algorithm. This new data product, version 5.10, displays substantially better both long- and short-term agreement with MLS ozone throughout the stratosphere due to the pointing correction. Previously reported stratospheric ozone trends over the time period 1984–2013, which were derived by merging the altitude/number density ozone profile measurements from the Stratospheric Aerosol and Gas Experiment (SAGE) II satellite instrument (1984–2005) and from OSIRIS (2002–2013) are recalculated using the new OSIRIS version 5.10 product, and extended to 2017. These results still show statistically significant positive trends throughout the upper stratosphere since 1997, but at weaker levels that are more closely in line with estimates from other data records.

scholarly journals Characterization of Odin-OSIRIS ozone profiles with the SAGE II dataset

2013 ◽  
Vol 6 (1) ◽  
pp. 1033-1065 ◽  
Author(s):  
C. Adams ◽  
A. E. Bourassa ◽  
A. F. Bathgate ◽  
C. A. McLinden ◽  
N. D. Lloyd ◽  
...  
Keyword(s):  
Infrared Imaging ◽  
Imaging System ◽  
Correlation Coefficients ◽  
Relative Difference ◽  
Stratospheric Aerosol ◽  
Density Profiles ◽  
Crossing Time ◽  
Ozone Trends ◽  
Relative Differences

Abstract. The Optical Spectrograph and InfraRed Imaging System (OSIRIS) on board the Odin spacecraft has been taking limb-scattered measurements of ozone number density profiles from 2001–present. The Stratospheric Aerosol and Gas Experiment II (SAGE II) took solar occultation measurements of ozone number densities from 1984–2005 and has been used in many studies of long-term ozone trends. We present the characterization of OSIRIS SaskMART v5.0x against the new SAGE II v7.00 ozone profiles for 2001–2005, the period over which these two missions had overlap. This information can be used to merge OSIRIS and other satellite ozone measurements with SAGE II into a single ozone record from 1984 to the present. Coincident measurement pairs were selected for &amp;pm;1 h, &amp;pm;1° latitude, and &amp;pm;500 km. The absolute value of the resulting mean relative difference profile was < 5% for 13.5–54.5km and < 3% for 24.5–53.5 km. Correlation coefficients R > 0.9 were calculated for 13.5–49.5 km, demonstrating excellent overall agreement between the two datasets. Coincidence criteria were relaxed to maximize the number of measurement pairs and the conditions under which measurements were taken. With the broad coincidence criteria, good agreement (< 5%) was observed under most conditions for 20.5–40.5 km. However, mean relative differences do exceed 5% under several cases. Above 50 km, differences between OSIRIS and SAGE II are partly attributed to the diurnal variation of ozone. OSIRIS data are biased high compared with SAGE II at 22.5 km, particularly at high latitudes. The OSIRIS optics temperature is low (< 16 °C) during May–July, when the satellite enters the Earth's shadow for part of its orbit. During this period, OSIRIS measurements are biased low by 5–12% for 27.5–38.5 km. Biases between OSIRIS ascending node (northward equatorial crossing time ~ 18:00 LT) and descending node (southward equatorial crossing time ~ 06:00 LT) measurements are also noted under some conditions. This work demonstrates that OSIRIS and SAGE II have excellent overall agreement and characterizes the biases between these datasets.

scholarly journals Further analyses of the decadal-scale responses and trends in middle and upper stratospheric ozone from SAGE II and HALOE

2011 ◽  
Vol 11 (9) ◽  
pp. 25011-25036
Author(s):  
E. E. Remsberg
Keyword(s):  
Linear Trend ◽  
Stratospheric Ozone ◽  
Stratospheric Aerosol ◽  
Model Fit ◽  
Number Density ◽  
Temperature Trends ◽  
Decadal Scale ◽  
Ozone Trends ◽  
Solar Uv ◽  
Middle Stratosphere

Abstract. Stratospheric Aerosol and Gas Experiment (SAGE II) Version 6.2 ozone profiles are analyzed for their decadal-scale responses and linear trends in the middle and upper stratosphere from 1984 through 1998. The results are compared with those of SAGE II and of the Halogen Occultation Experiment (HALOE) for 1991–2005, reported previously by Remsberg and Lingenfelser (2010). The regression model fit to the data includes a periodic 11- term, and it is in-phase with that of the 11-yr solar uv-flux throughout most of the latitude/altitude domain of the middle and upper stratosphere. Max minus min responses for the upper stratosphere are of order 2% from the HALOE time series that are in terms of mixing ratio versus pressure. Max minus min responses are of order 4% from SAGE II in terms of number density versus altitude and for both 1984–1998 and 1991–2005, even though the concurrent linear trend term coefficients are much different for the two time spans. However, the analyzed 11-yr response from the SAGE II data of 1984–1998 lags that of the uv-flux by 1 to 2 yr in the tropical middle stratosphere, most likely due to the effects of ENSO forcings that are not represented in the regression models. The linear ozone trends in the upper stratosphere for 1991 to 2005 are of the order of −2 to −3%/decade from SAGE II and 0 to −1%/decade from HALOE. Those differences in the ozone trends must be principally due to the associated temperature trends for the analyzed data.

scholarly journals Decadal-scale responses in middle and upper stratospheric ozone from SAGE II Version 7 data

2013 ◽  
Vol 13 (8) ◽  
pp. 20239-20274
Author(s):  
E. E. Remsberg
Keyword(s):  
Time Series ◽  
Linear Trend ◽  
Stratospheric Ozone ◽  
Stratospheric Aerosol ◽  
Number Density ◽  
Middle Latitudes ◽  
Decadal Scale ◽  
Ozone Trends ◽  
Solar Uv ◽  
Response Profiles

Abstract. Stratospheric Aerosol and Gas Experiment (SAGE II) version 7 (v7) ozone profiles are analyzed for their decadal-scale responses and linear trends in the middle and upper stratosphere for the two periods of 1984 to 1998 and 1991 to 2005. Multiple linear regression (MLR) analysis is applied to time series of the v7 ozone number density vs. altitude data for a range of latitudes and altitudes. The MLR models that are fit to the data include a periodic 11 yr term, and it is in-phase with that of the 11-yr, solar uv-flux throughout most of the latitude/altitude domain of the middle and upper stratosphere. Max minus min, solar cycle (SC-like) responses for the SAGE II ozone at those altitudes and for the low to middle latitudes are similar for 1984–1998 and for 1991–2005 and of the order of 5 to 2.5% from 35 to 50 km. This finding is important because the associated linear trend terms are clearly different from the MLR models of those two time spans. The SAGE II results for the upper stratosphere are also compared with those of the Halogen Occultation Experiment (HALOE) in terms of mixing ratio vs. pressure. The shapes of their respective, SC-like response profiles agree well for a time series from late 1992–2005, or after excluding the first 14 months of data following the Pinatubo eruption. Max minus min, SC-like responses from the SAGE II and HALOE time series vary from 2 to 4% and from 0 to 2%, respectively, and their differences in the upper stratosphere can be accounted for using the analyzed, SC-like response of the HALOE temperatures. The linear ozone trends of the upper stratosphere for 1992–2005 vary from about 0 to −4% decade−1 from the Southern to the Northern Hemisphere from SAGE II, while they vary from 0 to −2% decade−1 and are more nearly symmetric about the Equator from HALOE.

scholarly journals Drift-corrected Odin-OSIRIS ozone product: algorithm and updated stratospheric ozone trends

2018 ◽  
Vol 11 (1) ◽  
pp. 489-498 ◽  
Author(s):  
Adam E. Bourassa ◽  
Chris Z. Roth ◽  
Daniel J. Zawada ◽  
Landon A. Rieger ◽  
Chris A. McLinden ◽  
...  
Keyword(s):  
Stratospheric Ozone ◽  
Stratospheric Aerosol ◽  
Retrieval Algorithm ◽  
Number Density ◽  
Short Term ◽  
Time Period ◽  
Infrared Imager ◽  
Ozone Profile ◽  
Ozone Trends

Abstract. A small long-term drift in the Optical Spectrograph and Infrared Imager System (OSIRIS) stratospheric ozone product, manifested mostly since 2012, is quantified and attributed to a changing bias in the limb pointing knowledge of the instrument. A correction to this pointing drift using a predictable shape in the measured limb radiance profile is implemented and applied within the OSIRIS retrieval algorithm. This new data product, version 5.10, displays substantially better both long- and short-term agreement with Microwave Limb Sounder (MLS) ozone throughout the stratosphere due to the pointing correction. Previously reported stratospheric ozone trends over the time period 1984–2013, which were derived by merging the altitude–number density ozone profile measurements from the Stratospheric Aerosol and Gas Experiment (SAGE) II satellite instrument (1984–2005) and from OSIRIS (2002–2013), are recalculated using the new OSIRIS version 5.10 product and extended to 2017. These results still show statistically significant positive trends throughout the upper stratosphere since 1997, but at weaker levels that are more closely in line with estimates from other data records.

379: A Critical Analysis of the Interpretation of Biochemical Recurrence in Surgically Treated Patients using the Revised ASTRO Criterion–"NADIR +2"

2007 ◽  
Vol 177 (4S) ◽  
pp. 126-126
Author(s):  
Matthew E. Nielsen ◽  
Danil V. Makarov ◽  
Elizabeth B. Humphreys ◽  
Leslie A. Mangold ◽  
Alan W. Partin ◽  
...  
Keyword(s):  
Biochemical Recurrence ◽  
Critical Analysis
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