An absolute cavity pyrgeometer to measure the absolute outdoor longwave irradiance with traceability to international system of units, SI

Reda, Ibrahim; Zeng, Jinan; Scheuch, Jonathan; Hanssen, Leonard M.; Wilthan, Boris; Myers, D.; Stoffel, T.

doi:10.1016/j.jastp.2011.12.011

Cited by 18 publications

(49 citation statements)

References 7 publications

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“…This result needs to be confirmed by further independent measurements, for example by the absolute cavity radiometer [4].…”

Section: Resultsmentioning

confidence: 83%

Longwave irradiance measurements using IRIS radiometers at the PMOD/WRC-IRS

Gröbner¹,

Wacker²

2013

AIP Conference Proceedings

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Abstract. Measurements between a newly developed windowless longwave irradiance radiometer IRIS at PMOD/WRC and commercially available pyrgeometers based on thermopile detectors show seasonal variations of up to 6 Wm -2 between different instrument groups which are likely due to the spectral mismatch of the dome transmissions of the respective pyrgeometers. The measurements at PMOD/WRC suggest that Eppley PIR and PRE2003 CG4 (Kipp & Zonen CG4 Pyrgeometers manufactured before 2003) require a longwave irradiance correction of about -0.5 Wm -2 mm -1 IWV when the atmospheric integrated precipitable water vapor (IWV) falls below 10 mm, while POST2003 CG4 do not show these discrepancies and give consistent results with respect to the IRIS Radiometers. The IRIS radiometers measure on average 4.6±2.5 Wm -2 higher longwave irradiances than the WISG (for IWV>10 mm), which needs to be confirmed by independent measurements.

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“…This result needs to be confirmed by further independent measurements, for example by the absolute cavity radiometer [4].…”

Section: Resultsmentioning

confidence: 83%

Longwave irradiance measurements using IRIS radiometers at the PMOD/WRC-IRS

Gröbner¹,

Wacker²

2013

AIP Conference Proceedings

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“…Although not the focus of this study, the observed offset of the WISG and IRIS/ACP reference scales should be further investigated by more independent and comprehensive inter-comparison measurements as previously suggested (Reda et al, 2012;Gröbner et al, 2014;Philipona, 2015). In this regard, several IRIS radiometers will be characterised in the immediate future, and their traceability to SI units determined within the European Metrology Programme for Innovation and Research (EMPIR), together with partners from the metrology community.…”

Section: Discussionmentioning

confidence: 88%

“…The realisation of a more accurate standard group to determine irradiance (Reda et al, 2012) and a revision of the WISG scale have been ongoing issues in recent years (e.g. Gröbner et al, 2014Philipona, 2015).…”

Section: Evidence For a Revision Of The Wisg Reference Scalementioning

confidence: 99%

“…However, a replacement of the WISG as a transfer standard is not foreseen due to its all-weather and hence continuous measurement capabilities. Current state-of-the-art research radiometers such as the Infrared Integrating Sphere radiometer (IRIS; Gröbner, 2012) and the Absolute Cavity Pyrgeometer (ACP; Reda et al, 2012) are windowless and are thus not suitable for continuous all-weather operation. The evidence for a reference scale revision comes from concurrent operation of the WISG alongside IRIS during night-time clear-sky conditions since 2008 which yielded an underestimation of the WISG clear-sky longwave irradiance by 2-6 W m −2 , depending on the amount of integrated water vapour (IWV) (Gröbner et al, 2014) in the atmosphere.…”

Section: Evidence For a Revision Of The Wisg Reference Scalementioning

confidence: 99%

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Revising shortwave and longwave radiation archives in view of possible revisions of the WSG and WISG reference scales: methods and implications

et al. 2017

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Abstract. A large number of radiometers are traceable to the World Standard Group (WSG) for shortwave radiation and the interim World Infrared Standard Group (WISG) for longwave radiation, hosted by the PhysikalischMeteorologisches Observatorium Davos/World Radiation Centre (PMOD/WRC, Davos, Switzerland). The WSG and WISG have recently been found to over-and underestimate radiation values, respectively (Fehlmann et al., 2012; Gröb-ner et al., 2014), although research is still ongoing. In view of a possible revision of the reference scales of both standard groups, this study discusses the methods involved and the implications on existing archives of radiation time series, such as the Baseline Surface Radiation Network (BSRN). Based on PMOD/WRC calibration archives and BSRN data archives, the downward longwave radiation (DLR) time series over the 2006-2015 period were analysed at four stations (polar and mid-latitude locations). DLR was found to increase by up to 3.5 and 5.4 W m −2 for all-sky and clearsky conditions, respectively, after applying a WISG reference scale correction and a minor correction for the dependence of pyrgeometer sensitivity on atmospheric integrated water vapour content. Similar increases in DLR may be expected at other BSRN stations. Based on our analysis, a number of recommendations are made for future studies.

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“…This poor performance led to the development of reference pyrgeometers to measure absolute values of L d and the establishment of WISG references at PMOD/WRC. Many efforts have been made to develop reference pyrgeometers [ Philipona et al ., ; Reda et al ., ; Reda et al ., ]. At PMOD/WRC, a pyrgeometer is first calibrated with a laboratory blackbody, and then it is deployed in the field and compared to a reference group of pyrgeometers to adjust the laboratory calibration factors [ Gröbner and Los , ; Meloni et al ., ].…”

Section: Review Of Existing Estimates Of Global Ldmentioning

confidence: 99%

Global atmospheric downward longwave radiation at the surface from ground‐based observations, satellite retrievals, and reanalyses

Wang

Dickinson

2013

Reviews of Geophysics

155

141

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[1] Atmospheric downward longwave radiation at the surface (L d ) varies with increasing CO 2 and other greenhouse gases. This study quantifies the uncertainties of current estimates of global L d at monthly to decadal timescales and its global climatology and trends during the past decades by a synthesis of the existing observations, reanalyses, and satellite products. We find that current L d observations have a standard deviation error of~3.5 W m À2 on a monthly scale. Citation: Wang, K., and R. E. Dickinson (2013), Global atmospheric downward longwave radiation at the surface from ground-based observations, satellite retrievals, and reanalyses, Rev. Geophys., 51, 150-185,

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An absolute cavity pyrgeometer to measure the absolute outdoor longwave irradiance with traceability to international system of units, SI

Cited by 18 publications

References 7 publications

Longwave irradiance measurements using IRIS radiometers at the PMOD/WRC-IRS

Longwave irradiance measurements using IRIS radiometers at the PMOD/WRC-IRS

Revising shortwave and longwave radiation archives in view of possible revisions of the WSG and WISG reference scales: methods and implications

Global atmospheric downward longwave radiation at the surface from ground‐based observations, satellite retrievals, and reanalyses

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