Satellite Instrument Calibration for Measuring Global Climate Change: Report of a Workshop

Ohring, George; Wielicki, Bruce A.; Spencer, Roy W.; Emery, Bill; Datla, Raju V.

doi:10.1175/bams-86-9-1303

Cited by 237 publications

(143 citation statements)

References 7 publications

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“…In spite of the enormous importance of detecting climate trends, before RO there were no global atmospheric observing systems that could meet the stringent climate monitoring requirements of 0.5 K accuracy and better than 0.10 K decade −1 stability (Ohring et al, 2005;Luntama et al, 2008). As shown above, RO observations meet these accuracy, stability and global sampling requirements.…”

Section: Climate Applicationsmentioning

confidence: 99%

Exploring Earth's atmosphere with radio occultation: contributions to weather, climate and space weather

2011

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Abstract. The launch of the proof-of-concept mission GPS/MET (Global Positioning System/Meteorology) in 1995 began a revolution in profiling Earth's atmosphere through radio occultation (RO). GPS/MET; subsequent single-satellite missions CHAMP (CHAllenging Minisatellite Payload), SAC-C (Satellite de Aplicaciones Cientificas-C), GRACE (Gravity Recovery and Climate Experiment), METOP-A, and TerraSAR-X (Beyerle et al., 2010); and the six-satellite constellation, FORMOSAT-3/COSMIC (Formosa Satellite mission #3/Constellation Observing System for Meteorology, Ionosphere, and Climate) have proven the theoretical capabilities of RO to provide accurate and precise profiles of electron density in the ionosphere and refractivity, containing information on temperature and water vapor, in the stratosphere and troposphere. This paper summarizes results from these RO missions and the applications of RO observations to atmospheric research and operational weather analysis and prediction.

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Section: Climate Applicationsmentioning

confidence: 99%

Exploring Earth's atmosphere with radio occultation: contributions to weather, climate and space weather

2011

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“…Many of the key indicators of climate change require the detection of subtle changes over decades. In the solar-reflective (SR) domain (<2500 nm), this can be at the level of less than 1 per cent per decade, and in the IR 0.2 K per decade [1,5]. Because no existing EO optical sensor comes close to achieving this level of accuracy, strategies have been devised that seek to monitor change by maintaining an overlapping time series of measurements, wherever possible using similar heritage instrumentation.…”

Section: (B) Earth Observation Data Qualitymentioning

confidence: 99%

Accurate radiometry from space: an essential tool for climate studies

Fox

Kaiser-Weiss

Schmutz

et al. 2011

Phil. Trans. R. Soc. A.

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The Earth's climate is undoubtedly changing; however, the time scale, consequences and causal attribution remain the subject of significant debate and uncertainty. Detection of subtle indicators from a background of natural variability requires measurements over a time base of decades. This places severe demands on the instrumentation used, requiring measurements of sufficient accuracy and sensitivity that can allow reliable judgements to be made decades apart. The International System of Units (SI) and the network of National Metrology Institutes were developed to address such requirements. However, ensuring and maintaining SI traceability of sufficient accuracy in instruments orbiting the Earth presents a significant new challenge to the metrology community. This paper highlights some key measurands and applications driving the uncertainty demand of the climate community in the solar reflective domain, e.g. solar irradiances and reflectances/radiances of the Earth. It discusses how meeting these uncertainties facilitate significant improvement in the forecasting abilities of climate models. After discussing the current state of the art, it describes a new satellite mission, called TRUTHS, which enables, for the first time, high-accuracy SI traceability to be established in orbit. The direct use of a 'primary standard' and replication of the terrestrial traceability chain extends the SI into space, in effect realizing a 'metrology laboratory in space'.

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“…In particular, observational data that is accurate, consistent, long-term, well characterised, and global in scope. The target requirements of these data are typically in the following ranges: spatial resolution of ∼ 50 km, temporal resolution of ∼ 3 h, cloud amount accuracy of between 0.01 and 0.05, cloud pressure accuracy of 15 and 50 hPa, cloud temperature accuracy of between 1 and 5 K, cloud water path accuracy of 25 %, and cloud effective radius accuracy of between 5 and 10 % (Ohring et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Synergy of stereo cloud top height and ORAC optimal estimation cloud retrieval: evaluation and application to AATSR

et al. 2016

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Abstract. In this paper we evaluate the impact on the cloud parameter retrievals of the ORAC (Optimal Retrieval of Aerosol and Cloud) algorithm following the inclusion of stereo-derived cloud top heights as a priori information. This is performed in a mathematically rigorous way using the ORAC optimal estimation retrieval framework, which includes the facility to use such independent a priori information. Key to the use of a priori information is a characterisation of their associated uncertainty. This paper demonstrates the improvements that are possible using this approach and also considers their impact on the microphysical cloud parameters retrieved. The Along-Track Scanning Radiometer (AATSR) instrument has two views and three thermal channels, so it is well placed to demonstrate the synergy of the two techniques. The stereo retrieval is able to improve the accuracy of the retrieved cloud top height when compared to collocated Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO), particularly in the presence of boundary layer inversions and high clouds. The impact of the stereo a priori information on the microphysical cloud properties of cloud optical thickness (COT) and effective radius (RE) was evaluated and generally found to be very small for single-layer clouds conditions over open water (mean RE differences of 2.2 (±5.9) microns and mean COD differences of 0.5 (±1.8) for single-layer ice clouds over open water at elevations of above 9 km, which are most strongly affected by the inclusion of the a priori).

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Satellite Instrument Calibration for Measuring Global Climate Change: Report of a Workshop

Cited by 237 publications

References 7 publications

Exploring Earth's atmosphere with radio occultation: contributions to weather, climate and space weather

Exploring Earth's atmosphere with radio occultation: contributions to weather, climate and space weather

Accurate radiometry from space: an essential tool for climate studies

Synergy of stereo cloud top height and ORAC optimal estimation cloud retrieval: evaluation and application to AATSR

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