Engineering topics

Flynn, Larry

Publications and source records attributed to Flynn, Larry.

4 records

NASA NTRS2014

Evaluation of the Sensor Data Record from the Nadir Instruments of the Ozone Mapping Profiler Suite (OMPS)

This paper evaluates the first 15 months of the Ozone Mapping and Profiler Suite (OMPS) Sensor Data Record (SDR) acquired by the nadir sensors and processed by the National Oceanic and Atmospheric Administration Interface Data Processing Segment. The evaluation consists of an inter-comparison with a similar satellite instrument, an analysis using a radiative transfer model, and an assessment of product stability. This is in addition to the evaluation of sensor calibration and the Environment Data Record product that are also reported in this Special Issue. All these are parts of synergetic effort to provide comprehensive assessment at every level of the products to ensure its quality. It is found that the OMPS nadir SDR quality is satisfactory for the current Provisional maturity. Methods used in the evaluation are being further refined, developed, and expanded, in collaboration with international community through the Global Space-based Inter-Calibration System, to support the upcoming long-term monitoring.

validation↗

NASA NTRS2013

The Version 8.6 SBUV Ozone Data Record: An Overview

Under a NASA program to produce long-term data records from instruments on multiple satellites, data from a series of nine Solar Backscatter Ultraviolet (SBUV and SBUV2) instruments have been re-processed to create a coherent ozone time series. Data from the BUV instrument on Nimbus 4, SBUV on Nimbus 7, and SBUV2 instruments on NOAA 9, 11, 14, 16, 17, 18, and 19 covering the period 1970-1972 and 1979-2011 were used to create a long-term data set. The goal is an ozone Earth Science Data Record - a consistent, calibrated ozone time series that can be used for trend analyses and other studies. In order to create this ozone data set, the radiances were adjusted and used to re-process the entire data records for each of the nine instruments. Inter-instrument comparisons during periods of overlap as well as comparisons with data from other satellite and ground-based instruments were used to evaluate the consistency of the record and make calibration adjustments as needed. Additional improvements in this version 8.6 processing included the use of the Brion, Daumont, and Malicet ozone cross sections, and a cloud-height climatology derived from Aura OMI measurements. Validation of the re-processed ozone shows that total column ozone is consistent with the Brewer Dobson network to within about 1 for the new time series. Comparisons with MLS, SAGE, sondes, and lidar show that ozone at individual levels in the stratosphere is generally consistent to within 5 percent.

ozone↗

NASA NTRS2000

On the Long-Term Calibration of the TOMS Total Ozone Record

Comparison of Total Ozone Mapping Spectrometer (TOMS) data to the network of ground-based Dobson/Brewer measurements reveals difference in the time dependence of the calibration of the two systems. We have been searching for a method to determine the time dependence of the TOMS calibrations that is independent of the Dobson/Brewer network. In a separate paper by DeLand et al., calibrations of the Solar Backscatter UV Spectrometer (SBUV) instruments have been rederived using the D-pair (306/313 nm wavelengths) data at the equator. These calibrations have been applied to the data from the Nimbus 7 SBUV and the NOAA 9 and 11 SBUV/2 data to derive a new version 7 data set for each instrument. We have used these data to do a detailed comparison to the Nimbus 7 and Earth Probe TOMS data. Assuming that the D-pair establishes the correct calibration, these comparisons reveal some small calibration drifts (approximately 1%) in the TOMS data. They also reveal an offset in the D-pair calibration with respect to the Dobson network of approximately 8 Dobson units with the Dobson being lower than the D-pair. The D-pair calibration offsets have been used to create a merged ozone data set from TOMS with a calibration that has been determined independent of the Dobson/Brewer network. Trend analyses of these data will be presented and compared to trend analyses using the ground-based data.

Stolarski, Richard S.↗

NASA NTRS2000

Merged Long-Term Data Sets from TOMS and SBUV Total Ozone Measurements

Total ozone has been measured by a series of nadir-viewing satellite instruments. These measurements begin with the Total Ozone Mapping Spectrometer (TOMS) and Solar Backscatter UltraViolet (SBUV) instruments on Nimbus 7, launched in late 1978. The measurements have continued with the Meteor 3 TOMS, Earth Probe TOMS, and NOAA 9,11,14 SBUV/2 instruments. The problem for producing a long-term data set is establishing the relative calibration of the various instruments to better than 1%. There was a nearly two year gap between the Meteor 3 TOMS and the Earth Probe TOMS. This gap is filled by the NOAA 9 and 11 SBUV/2 instruments, but they were in drifting orbits that result in effective gaps in the record when the equator crossing time occurs at large solar zenith angle. We have used recently re-derived calibrations of the SBUV instruments using the D-pair (306/313 nm wavelengths) data at the equator. These equatorial D-pair measurements should maintain the internal calibration of each instrument better than previous approaches. We then use the comparisons between instruments during their overlap periods to establish a consistent calibration over the entire data set. The resulting merged ozone data set is independent of the ground-based Dobson/Brewer network.

Stolarski, Richard↗