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

Nash, John F.; Saunders, Roger

doi:10.1002/qj.2505

Cited by 25 publications

(38 citation statements)

References 24 publications

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“…Although Zou et al did not compare their results to models, visual inspection of their version 2 temperatures indicates much closer agreement with the model results shown in Thompson et al (2012). There has also been a subsequent revision of the Met Office data set (Nash and Saunders, 2015).…”

Section: Mclandress Et Al: a Methods For Merging Nadir-sounding CLmentioning

confidence: 87%

“…Note that the vertically resolved temperature data from global positioning system (GPS) radio occultation only begin in the current century (Wickert et al, 2001), and do not reach into the upper stratosphere, where the strongest cooling is found. The nadir-sounding measurements were never designed for climate monitoring, and homogenizing the data from different operational satellites, with rapidly drifting orbits, is a challenge (Wang et al, 2012;Zou et al, 2014;Nash and Saunders, 2015).…”

Section: Mclandress Et Al: a Methods For Merging Nadir-sounding CLmentioning

confidence: 99%

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A method for merging nadir-sounding climate records, with an application to the global-mean stratospheric temperature data sets from SSU and AMSU

et al. 2015

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Abstract.A method is proposed for merging different nadirsounding climate data records using measurements from high-resolution limb sounders to provide a transfer function between the different nadir measurements. The two nadirsounding records need not be overlapping so long as the limb-sounding record bridges between them. The method is applied to global-mean stratospheric temperatures from the NOAA Climate Data Records based on the Stratospheric Sounding Unit (SSU) and the Advanced Microwave Sounding Unit-A (AMSU), extending the SSU record forward in time to yield a continuous data set from 1979 to present, and providing a simple framework for extending the SSU record into the future using AMSU. SSU and AMSU are bridged using temperature measurements from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS), which is of high enough vertical resolution to accurately represent the weighting functions of both SSU and AMSU. For this application, a purely statistical approach is not viable since the different nadir channels are not sufficiently linearly independent, statistically speaking. The near-global-mean linear temperature trends for extended SSU for 1980-2012 are −0.63 ± 0.13, −0.71 ± 0.15 and −0.80 ± 0.17 K decade −1 (95 % confidence) for channels 1, 2 and 3, respectively. The extended SSU temperature changes are in good agreement with those from the Microwave Limb Sounder (MLS) on the Aura satellite, with both exhibiting a cooling trend of ∼ 0.6 ± 0.3 K decade −1 in the upper stratosphere from 2004 to 2012. The extended SSU record is found to be in agreement with high-top coupled atmosphere-ocean models over the 1980-2012 period, including the continued cooling over the first decade of the 21st century.

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Section: Mclandress Et Al: a Methods For Merging Nadir-sounding CLmentioning

confidence: 87%

Section: Mclandress Et Al: a Methods For Merging Nadir-sounding CLmentioning

confidence: 99%

A method for merging nadir-sounding climate records, with an application to the global-mean stratospheric temperature data sets from SSU and AMSU

et al. 2015

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“…Unless their relative contributions are clarified, it is difficult to make further comments on reliability of any of these trends. From the viewpoint of reanalysis, the reliability of stratospheric temperature variations could be improved by taking account of the missing factors in the forecast model, correcting known problems in calibration (Nash and Saunders 2013) and improving radiative transfer modeling for upper stratospheric temperature channels (Kobayashi et al 2009), thereby reducing the dependence on VarBC.…”

Section: Middle To Top Stratospherementioning

confidence: 99%

The JRA-55 Reanalysis: General Specifications and Basic Characteristics

Kobayashi

Ota

Harada

et al. 2015

Journal of the Meteorological Society of Japan

3,779

2,524

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The Japan Meteorological Agency (JMA) conducted the second Japanese global atmospheric reanalysis, called the Japanese 55-year Reanalysis or JRA-55. It covers the period from 1958, when regular radiosonde observations began on a global basis. JRA-55 is the first comprehensive reanalysis that has covered the last half-century since the European Centre for Medium-Range Weather Forecasts 45-year Reanalysis (ERA-40), and is the first one to apply four-dimensional variational analysis to this period. The main objectives of JRA-55 were to address issues found in previous reanalyses and to produce a comprehensive atmospheric dataset suitable for studying multidecadal variability and climate change. This paper describes the observations, data assimilation system, and forecast model used to produce JRA-55 as well as the basic characteristics of the JRA-55 product.JRA-55 has been produced with the TL319 version of JMA's operational data assimilation system as of December 2009, which was extensively improved since the Japanese 25-year Reanalysis (JRA-25). It also uses several newly available and improved past observations. The resulting reanalysis products are considerably better than the JRA-25 product. Two major problems of JRA-25 were a cold bias in the lower stratosphere, which has been diminished, and a dry bias in the Amazon basin, which has been mitigated. The temporal consistency of temperature analysis has also been considerably improved compared to previous reanalysis products. Our initial quality evaluation revealed problems such as a warm bias in the upper troposphere, large upward imbalance in the global mean net energy fluxes at the top of the atmosphere and at the surface, excessive precipitation over the tropics, and unrealistic trends in analyzed tropical cyclone strength. This paper also assesses the impacts of model biases and changes in the observing system, and mentions efforts to further investigate the representation of low-frequency variability and trends in JRA-55.

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“…See, e.g. Christy et al (2003), Wang et al (2012), Wang and Zou (2014), Zou et al (2014), and Nash and Saunders (2015) for these satellite temperature measurements.…”

Section: Introductionmentioning

confidence: 99%

Global temperature response to the major volcanic eruptions in multiple reanalysis data sets

et al. 2015

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Abstract. The global temperature responses to the eruptions of Mount Agung in 1963, El Chichón in 1982, and Mount Pinatubo in 1991 are investigated using nine currently available reanalysis data sets (JRA-55, MERRA, ERA-Interim, NCEP-CFSR, JRA-25, ERA-40, NCEP-1, NCEP-2, and 20CR). Multiple linear regression is applied to the zonal and monthly mean time series of temperature for two periods, 1979-2009 (for eight reanalysis data sets) and 1958-2001 (for four reanalysis data sets), by considering explanatory factors of seasonal harmonics, linear trends, QuasiBiennial Oscillation, solar cycle, and El Niño Southern Oscillation. The residuals are used to define the volcanic signals for the three eruptions separately, and common and different responses among the older and newer reanalysis data sets are highlighted for each eruption. In response to the Mount Pinatubo eruption, most reanalysis data sets show strong warming signals (up to 2-3 K for 1-year average) in the tropical lower stratosphere and weak cooling signals (down to −1 K) in the subtropical upper troposphere. For the El Chichón eruption, warming signals in the tropical lower stratosphere are somewhat smaller than those for the Mount Pinatubo eruption. The response to the Mount Agung eruption is asymmetric about the equator with strong warming in the Southern Hemisphere midlatitude upper troposphere to lower stratosphere. Comparison of the results from several different reanalysis data sets confirms the atmospheric temperature response to these major eruptions qualitatively, but also shows quantitative differences even among the most recent reanalysis data sets. The consistencies and differences among different reanalysis data sets provide a measure of the confidence and uncertainty in our current understanding of the volcanic response. The results of this intercomparison study may be useful for validation of climate model responses to volcanic forcing and for assessing proposed geoengineering by stratospheric aerosol injection, as well as to link studies using only a single reanalysis data set to other studies using a different reanalysis data set.

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

Cited by 25 publications

References 24 publications

A method for merging nadir-sounding climate records, with an application to the global-mean stratospheric temperature data sets from SSU and AMSU

A method for merging nadir-sounding climate records, with an application to the global-mean stratospheric temperature data sets from SSU and AMSU

The JRA-55 Reanalysis: General Specifications and Basic Characteristics

Global temperature response to the major volcanic eruptions in multiple reanalysis data sets

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