Early results based on the stratospheric channels of TOVS on the TIROS-N series of operational satellites

Pick, D. R.; Brownscombe, J. L.

doi:10.1016/0273-1177(81)90067-3

Cited by 37 publications

(16 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…AMSU-A provides microwave temperature-sounding data with greater vertical resolution than MSU, but has been flown only since 1998. The operational raw-radiance assimilation scheme was thus extended for ERA-40 to process data from additional HIRS channels to provide extra tropospheric resolution, and from the SSU (Pick and Brownscombe 1981) to provide stratospheric coverage. This was the first time the SSU radiances had been used in multivariate data assimilation.…”

Section: (D) Surface Analysismentioning

confidence: 99%

The ERA‐40 re‐analysis

Uppala

Kållberg

Simmons

et al. 2005

Quart J Royal Meteoro Soc

6,567

4,691

View full text Add to dashboard Cite

SUMMARY ERA-40 is a re-analysis of meteorological observations from September 1957 to August 2002 produced by the European Centre for Medium-Range Weather Forecasts (ECMWF) in collaboration with many institutions. The observing system changed considerably over this re-analysis period, with assimilable data provided by a succession of satellite-borne instruments from the 1970s onwards, supplemented by increasing numbers of observations from aircraft, ocean-buoys and other surface platforms, but with a declining number of radiosonde ascents since the late 1980s. The observations used in ERA-40 were accumulated from many sources. The first part of this paper describes the data acquisition and the principal changes in data type and coverage over the period. It also describes the data assimilation system used for ERA-40. This benefited from many of the changes introduced into operational forecasting since the mid-1990s, when the systems used for the 15-year ECMWF re-analysis (ERA-15) and the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) re-analysis were implemented. Several of the improvements are discussed. General aspects of the production of the analyses are also summarized.A number of results indicative of the overall performance of the data assimilation system, and implicitly of the observing system, are presented and discussed. The comparison of background (short-range) forecasts and analyses with observations, the consistency of the global mass budget, the magnitude of differences between analysis and background fields and the accuracy of medium-range forecasts run from the ERA-40 analyses are illustrated. Several results demonstrate the marked improvement that was made to the observing system for the * Corresponding author: European Centre for Medium-Range Weather Forecasts, Shinfield Park, Reading RG2 9AX, UK. e-mail: adrian.simmons@ecmwf. southern hemisphere in the 1970s, particularly towards the end of the decade. In contrast, the synoptic quality of the analysis for the northern hemisphere is sufficient to provide forecasts that remain skilful well into the medium range for all years. Two particular problems are also examined: excessive precipitation over tropical oceans and a too strong Brewer-Dobson circulation, both of which are pronounced in later years. Several other aspects of the quality of the re-analyses revealed by monitoring and validation studies are summarized. Expectations that the 'second-generation' ERA-40 re-analysis would provide products that are better than those from the firstgeneration ERA-15 and NCEP/NCAR re-analyses are found to have been met in most cases.

show abstract

Section: (D) Surface Analysismentioning

confidence: 99%

The ERA‐40 re‐analysis

Uppala

Kållberg

Simmons

et al. 2005

Quart J Royal Meteoro Soc

6,567

4,691

View full text Add to dashboard Cite

show abstract

“…Zou (2014; personal communication). Without a space‐view anomaly correction, channel 1 of TIROS‐N had a warm bias of around 0.5 K for the Earth views, and similarly channel 1 of NOAA‐6 was too low by 0.7 K. With space‐view anomaly corrections applied, Pick and Brownscombe () found the average difference between TIROS‐N and NOAA‐6 channel 1 Earth views to be 0.12 K.…”

Section: Met Office Processing From Counts To Radiancesmentioning

confidence: 99%

A review of Stratospheric Sounding Unit radiance observations for climate trends and reanalyses

Nash

Saunders

2015

Quart J Royal Meteoro Soc

View full text Add to dashboard Cite

Stratospheric Sounding Units (SSU) on the NOAA polar‐orbiting satellites measured infrared radiances in the 15 μm CO2 band between late 1978 and mid‐2006. From these radiances a time series of layer‐mean stratospheric temperatures has been derived by several groups. Discrepancies in these temperature analyses have been highlighted recently and efforts are now underway to resolve the differences between them. This article is the Met Office response summarising the issues to be resolved in creating a climate data record from the different SSUs, including corrections for radiometric, spectroscopic and tidal differences. Calibration issues identified include the SSU space‐view anomaly and radiometric anomalies in the NOAA‐9 observations. The spectroscopic correction required for changing pressures in the pressure modulator cells is also outlined. The most important correction for the time series is for the solar diurnal and semi‐diurnal tides as the satellite overpass local times change. Comparisons with other stratospheric temperature trend analyses are made and the reasons for the differences discussed. The time series presented here show sustained drops in stratospheric temperatures at all levels after the El Chichon and Pinatubo eruptions but only small trends to lower temperatures between eruptions.

show abstract

“…Pick and Brownscome [] indicated that an electrical offset was introduced during the space view, associated with the switching of the blackbody PRT to a reference mode. This caused a constant bias in the uncorrected SSU radiances.…”

Section: Recalibration Of the Ssu Swath Level‐1c Radiancesmentioning

confidence: 99%

“…This caused a constant bias in the uncorrected SSU radiances. The space view corrections for TIROS‐N and NOAA‐6 were given in Pick and Brownscome [], although the sign of their values were incorrect and should be changed when being used (C. Z. Nash, personal communication, 2014). Except for these two satellites, the original records of the space view corrections for all other satellites were lost both at NOAA and the Met Office.…”

Section: Recalibration Of the Ssu Swath Level‐1c Radiancesmentioning

confidence: 99%

“…This is consistent with the UKMO approach. This selection was based on the fact that laboratory tests were made on NOAA‐6 for space view corrections for all three channels so its calibration errors were known to be small [ Pick and Brownscome , ]. The calibration offsets for all other satellites obtained from intersatellite biases were listed in Table .…”

Section: Recalibration Of the Ssu Swath Level‐1c Radiancesmentioning

confidence: 99%

See 1 more Smart Citation

Recalibration and merging of SSU observations for stratospheric temperature trend studies

et al. 2014

View full text Add to dashboard Cite

Long-term observations from the Stratospheric Sounding Unit (SSU) during 1979-2006 onboard NOAA historical polar orbiting satellites were recalibrated for climate change investigation. A two-point linear calibration equation, with cold space and an internal blackbody warm target as end-point references, was used to transfer SSU raw counts data into radiances. The warm target temperature was represented by measurements from the space side thermistor on the blackbody, and the cold space radiance was assumed to be zero. Space view corrections due to an electrical interference were applied. Intersatellite calibration was conducted simultaneously by applying calibration offsets determined from residual intersatellite biases. The recalibration reached an accuracy of 0.1-0.2 K for global means and thus is expected to improve the consistency in stratospheric temperature time series in climate reanalyses. The recalibrated SSU radiances were further adjusted to develop Version 2 of the NOAA stratospheric temperature time series. The effects being adjusted included those from changes in instrument cell pressure and atmospheric carbon dioxide concentration, viewing angle differences, and semidiurnal tides due to orbital drift. Intersatellite biases were carefully removed to ensure smooth transitions between satellite pairs. Differences from Version 1 included improved radiance calibration, improved adjusting schemes for diurnal drift and intersatellite biases, removal of time-varying cell pressure adjustment for NOAA-9 channel 1, and excluding NOAA-7 channel 2 in the time series. In addition to the final merged data set, intermediate synthetic time series corresponding to different adjustments were also created to quantify their impact on the final trend as well as its reliability and uncertainty. Excellent matching between satellite pairs, especially the 7 year overlaps between NOAA-11 and NOAA-14 during 1997-2004, in intermediate as well as the final time series provided strong evidence on the validity of adjustments and thus confidence on the resulting trends. The Version 2 global mean trends for 1979-2006 were À0.69 ± 0.18, À0.77 ± 0.15, and À0.85 ± 0.15 K/decade for SSU channels 1, 2, and 3, representing temperatures of middle stratosphere, upper stratosphere, and stratosphere-mesosphere, respectively. Among these, cooling of channel 2 was stronger and channel 3 weaker than those in UK Met Office (UKMO) data by about 1 K during the entire SSU period from 1979 to 2006. Finally, the average of the channel 1 and channel 3 anomalies in Version 2 was close to channel 2 anomalies to within 0.2 K for the entire 1979-2006 period with identical trends. This feature was found consistent with chemistry-climate model simulations.

show abstract

Early results based on the stratospheric channels of TOVS on the TIROS-N series of operational satellites

Cited by 37 publications

References 9 publications

The ERA‐40 re‐analysis

The ERA‐40 re‐analysis

A review of Stratospheric Sounding Unit radiance observations for climate trends and reanalyses

Recalibration and merging of SSU observations for stratospheric temperature trend studies

Contact Info

Product

Resources

About