Trends in Downwelling Longwave Radiance Over the Southern Great Plains

Liu, Lei; Huang, Yi; Gyakum, John R.; Turner, David D.; Gero, P. Jonathan

doi:10.1029/2021jd035949

Cited by 4 publications

(7 citation statements)

References 40 publications

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“…Our study shows that we can directly monitor the radiative impact (forcing + feedback) of greenhouse gas concentration changes (Figure 1b) just like the Keeling Curve for CO 2 concentrations (Keeling et al., 1976). Such long‐term monitoring was previously only possible at particular locations at the surface (Feldman et al., 2015; Liu et al., 2022) but now with AIRS we can produce an observational curve for top‐of‐atmosphere, global, heat changes. Furthermore, we show that there is a mix of IRF, adjustments, and feedback in nearly each part of the spectrum.…”

Section: Conclusion and Discussionmentioning

confidence: 99%

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Greenhouse Gas Forcing and Climate Feedback Signatures Identified in Hyperspectral Infrared Satellite Observations

Raghuraman,

Paynter,

Ramaswamy

et al. 2023

Geophysical Research Letters

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Global greenhouse gas forcing and feedbacks are the primary causes of climate change but have limited direct observations. Here we show that continuous, stable, global, hyperspectral infrared satellite measurements (2003–2021) display decreases in outgoing longwave radiation (OLR) in the CO2, CH4, and N2O absorption bands and increases in OLR in the window band and H2O absorption bands. By conducting global line‐by‐line radiative transfer simulations with 2003–2021 meteorological conditions, we show that increases in CO2, CH4, and N2O concentrations caused an instantaneous radiative forcing and stratospheric cooling adjustment that decreased OLR. The climate response, comprising surface and atmospheric feedbacks to radiative forcings and unforced variability, increased OLR. The spectral trends predicted by our climate change experiments using our general circulation model identify three bedrock principles of the physics of climate change in the satellite record: an increasing greenhouse effect, stratospheric cooling, and surface‐tropospheric warming.

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Section: Conclusion and Discussionmentioning

confidence: 99%

“…that contain internal variability uncertainty and observational uncertainty. The former, known to be the dominant uncertainty for such time series (Liu et al., 2022), is derived from the S.E. associated with linear fit through the anomalies time series, while the latter is accounted for by increasing the S.E.…”

Section: Observational Datamentioning

confidence: 99%

Greenhouse Gas Forcing and Climate Feedback Signatures Identified in Hyperspectral Infrared Satellite Observations

Raghuraman,

Paynter,

Ramaswamy

et al. 2023

Geophysical Research Letters

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“…1a, as determined in ref. 8 , can be accurately reconstructed by aggregating the contributions from the aforementioned variables (illustrated by the orange line in Fig. 1a), which indicates a high degree of closure of the radiance attribution based on the fingerprinting method.…”

Section: Clear-sky Dlr Change Attributionmentioning

confidence: 95%

“…AERI operates within a limited observational spectral range, inside of which it also suffers from contamination of water vapour inside the interferometer and relatively poor calibration accuracy at the edge of the detectors 8,30 . Consequently, AERI observations from 550 to 1400 cm -1 are employed to determine the scaling factors for various fingerprints, which in turn enable us to quantify the total contributions across the entire longwave spectral range (25 to 2000 cm -1 ).…”

Section: Methodsmentioning

confidence: 99%

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Ground radiative measurements reveal negative longwave cloud feedback

Liu,

Huang,

Gyakum

2024

Preprint

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Clouds profoundly influence Earth’s energy balance1-2. Observationally constraining cloud radiative feedback, a notably uncertain climate feedback mechanisms3-5, is crucial for improving predictions of climate change5-7. However, the quantification of cloud feedback faces challenges due to the complex effects of cloud changes on the energy balance, which are often entangled with the radiative impacts of other climate factors, and also due to the scarcity of long-term concurrent records of cloud properties and atmospheric radiation. In this work, we use an optimal spectral fingerprinting method designed to separate surface longwave cloud feedback from other surface forcings and feedbacks, by leveraging the unique spectral signatures of various meteorological variables in the long-term record of spectrally resolved downwelling longwave radiance at the Southern Great Plains site. We detect a prominent negative surface longwave cloud feedback, suggesting that cloud changes have a cooling effect on the surface and modulate the warming effect of increased greenhouse gas concentrations and atmospheric temperatures. Our findings establish a pivotal observational benchmark of radiative forcing and feedback needed for validating climate models.

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A Decomposition of the Atmospheric and Surface Contributions to the Outgoing Longwave Radiation

Huang

2022

JGR Atmospheres

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The outgoing longwave radiation (OLR), which consists of the thermal radiation from both the atmosphere and surface, is of critical importance to the Earth radiation energy budget. To understand the global OLR distribution, it is important to quantify the varying atmospheric and surface contributions. In this work, we present such a quantification using radiative transfer computations based on global reanalysis atmospheric data. By dissecting the OLR simulated following the radiative transfer equation, we quantitatively measure the layer‐wise atmospheric contributions to OLR and compare it to the surface contribution in different spectral bands. One focus of this study is on the OLR in the far‐infrared (FIR), for which new satellites are expected to provide unprecedented measurements. We find that around 45% of the global mean OLR is radiated in the FIR and in polar regions the FIR contribution can increase to 60%. Our vertical decomposition of OLR discloses that although the atmospheric contribution generally surpasses the surface contribution, the enhanced FIR contribution in the polar regions mainly results from a relatively stronger surface (as opposed to atmospheric) contribution. This is allowed by the opening of the atmospheric window in the FIR in these extremely dry regions. Our analysis also reveals that the tropopause layer makes a minimum contribution to the OLR, which may be a unique spectroscopic feature of the Earth atmosphere. Clouds are found to reduce the atmospheric contribution in the FIR while enhancing it in the mid‐infrared.

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Trends in Downwelling Longwave Radiance Over the Southern Great Plains

Cited by 4 publications

References 40 publications

Greenhouse Gas Forcing and Climate Feedback Signatures Identified in Hyperspectral Infrared Satellite Observations

Greenhouse Gas Forcing and Climate Feedback Signatures Identified in Hyperspectral Infrared Satellite Observations

Ground radiative measurements reveal negative longwave cloud feedback

A Decomposition of the Atmospheric and Surface Contributions to the Outgoing Longwave Radiation

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