The Water Vapour Continuum: Brief History and Recent Developments

Shine, Keith P.; Ptashnik, Igor V.; Rädel, G.

doi:10.1007/s10712-011-9170-y

Cited by 120 publications

(63 citation statements)

References 109 publications

(136 reference statements)

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“…7 Next, we calculated the OLR and albedo versus surface temperature for a range of CO 2 dry volume mixing ratios. Figure 3 shows (1) the OLR and (2) and (3) albedo for G-and M-star spectra, respectively, assuming Earth's gravity 7 Note that in Kopparapu et al (2013), it is stated that differences between the BPS and CKD continua (Shine et al 2012;Clough et al 1989) can cause up to 12 W m −2 difference in the OLR in the runaway limit. However, these authors later claim that their results closely correspond to Figure 4.37 in Pierrehumbert (2010), which was itself calculated using a continuum parameterization based on CKD.…”

Section: Variation Of Olr and Albedo With Surface Temperature And Co mentioning

confidence: 99%

WATER LOSS FROM TERRESTRIAL PLANETS WITH CO₂-RICH ATMOSPHERES

Wordsworth

Pierrehumbert

2013

ApJ

199

169

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Water photolysis and hydrogen loss from the upper atmospheres of terrestrial planets is of fundamental importance to climate evolution but remains poorly understood in general. Here we present a range of calculations we performed to study the dependence of water loss rates from terrestrial planets on a range of atmospheric and external parameters. We show that CO 2 can only cause significant water loss by increasing surface temperatures over a narrow range of conditions, with cooling of the middle and upper atmosphere acting as a bottleneck on escape in other circumstances. Around G-stars, efficient loss only occurs on planets with intermediate CO 2 atmospheric partial pressures (0.1-1 bar) that receive a net flux close to the critical runaway greenhouse limit. Because G-star total luminosity increases with time but X-ray and ultraviolet/ultravoilet luminosity decreases, this places strong limits on water loss for planets like Earth. In contrast, for a CO 2 -rich early Venus, diffusion limits on water loss are only important if clouds caused strong cooling, implying that scenarios where the planet never had surface liquid water are indeed plausible. Around M-stars, water loss is primarily a function of orbital distance, with planets that absorb less flux than ∼270 W m −2 (global mean) unlikely to lose more than one Earth ocean of H 2 O over their lifetimes unless they lose all their atmospheric N 2 /CO 2 early on. Because of the variability of H 2 O delivery during accretion, our results suggest that many "Earth-like" exoplanets in the habitable zone may have ocean-covered surfaces, stable CO 2 /H 2 O-rich atmospheres, and high mean surface temperatures.

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Section: Variation Of Olr and Albedo With Surface Temperature And Co mentioning

confidence: 99%

WATER LOSS FROM TERRESTRIAL PLANETS WITH CO₂-RICH ATMOSPHERES

Wordsworth

Pierrehumbert

2013

ApJ

199

169

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“…Although the continuum absorption in these windows, and its dependence on pressure and temperature, is now much better observed and characterised, there remains a lively debate on the underlying physical causes of this continuum. The historical perspective underpinning the development of a theory of water vapour continuum absorption has led to recent developments and experimental campaigns leading to new insights into this uncertain aspect of how water vapour influences the flows of radiative energy through the atmosphere (Shine et al 2012). Although improved representation of the water vapour continuum is likely to reduce uncertainty in Earth's radiative energy budget only marginally, it may have implications for the retrieval of physical quantities from space and therefore how we observe Earth's climate system.…”

Section: Radiative Effects Of Water Vapourmentioning

confidence: 99%

The Role of Water Vapour in Earth’s Energy Flows

Allan

2011

Surv Geophys

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Water vapour modulates energy flows in Earth's climate system through transfer of latent heat by evaporation and condensation and by modifying the flows of radiative energy both in the longwave and shortwave portions of the electromagnetic spectrum. This article summarizes the role of water vapour in Earth's energy flows with particular emphasis on (1) the powerful thermodynamic constraint of the Clausius Clapeyron equation, (2) dynamical controls on humidity above the boundary layer (or freetroposphere), (3) uncertainty in continuum absorption in the relatively transparent ''window'' regions of the radiative spectrum and (4) implications for changes in the atmospheric hydrological cycle.

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“…Another source of uncertainty is the so-called continuum absorption, especially due to water vapor. It is a spectrally less structured contribution dominating in window regions (e.g., Shine et al, 2012) which comprises two components: the self-continuum (attributed to H 2 O-H 2 O interactions) and the foreign continuum (attributed to H 2 O-air interactions). Although a definite continuum theory still does not exist, it seems that a consensus has been reached on the existence of the two possible physical processes contributing, namely (i) monomer contributions resulting from perturbations of the line shape due to (self-and foreign) pair interactions during molecular collisions and (ii) dimer contributions, i.e., absorption due to stable and/or metastable dimers.…”

Section: Introductionmentioning

confidence: 99%

“…Finally, a drawback of laboratory measurements is that they are typically performed at least at room temperature or even heated, in order to detect the weak continuum absorption in the limited optical path length of the cells. Therefore, for climate and remote sensing applications an extrapolation of continuum coefficients to the lower atmospheric temperatures is required, which may lead to significant inaccuracies due to the uncertainty of the selfcontinuum temperature dependence (e.g., Shine et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

The Zugspitze radiative closure experiment for quantifying water vapor absorption over the terrestrial and solar infrared – Part 1: Setup, uncertainty analysis, and assessment of far-infrared water vapor continuum

2016

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Abstract. Quantitative knowledge of water vapor radiative processes in the atmosphere throughout the terrestrial and solar infrared spectrum is still incomplete even though this is crucial input to the radiation codes forming the core of both remote sensing methods and climate simulations. Beside laboratory spectroscopy, ground-based remote sensing field studies in the context of so-called radiative closure experiments are a powerful approach because this is the only way to quantify water absorption under cold atmospheric conditions. For this purpose, we have set up at the Zugspitze (47.42 • N, 10.98 • E; 2964 m a.s.l.) a long-term radiative closure experiment designed to cover the infrared spectrum between 400 and 7800 cm −1 (1.28-25 µm). As a benefit for such experiments, the atmospheric states at the Zugspitze frequently comprise very low integrated water vapor (IWV; minimum = 0.1 mm, median = 2.3 mm) and very low aerosol optical depth (AOD = 0.0024-0.0032 at 7800 cm −1 at air mass 1). All instruments for radiance measurements and atmospheric-state measurements are described along with their measurement uncertainties. Based on all parameter uncertainties and the corresponding radiance Jacobians, a systematic residual radiance uncertainty budget has been set up to characterize the sensitivity of the radiative closure over the whole infrared spectral range. The dominant uncertainty contribution in the spectral windows used for far-infrared (FIR) continuum quantification is from IWV uncertainties, while T profile uncertainties dominate in the mid-infrared (MIR). Uncertainty contributions to near-infrared (NIR) radiance residuals are dominated by water vapor line parameters in the vicinity of the strong water vapor bands. The window regions in between these bands are dominated by solar Fourier transform infrared (FTIR) calibration uncertainties at low NIR wavenumbers, while uncertainties due to AOD become an increasing and dominant contribution towards higher NIR wavenumbers. Exceptions are methane or nitrous oxide bands in the NIR, where the associated line parameter uncertainties dominate the overall uncertainty.As a first demonstration of the Zugspitze closure experiment, a water vapor continuum quantification in the FIR spectral region (400-580 cm −1 ) has been performed. The resulting FIR foreign-continuum coefficients are consistent with the MT_CKD 2.5.2 continuum model and also agree with the most recent atmospheric closure study carried out in Antarctica. Results from the first determination of the NIR water vapor continuum in a field experiment are detailed in a companion paper (Reichert and Sussmann, 2016) while a novel NIR calibration scheme for the underlying FTIR measurements of incoming solar radiance is presented in another companion paper .

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The Water Vapour Continuum: Brief History and Recent Developments

Abstract: International audienc

Cited by 120 publications

References 109 publications

WATER LOSS FROM TERRESTRIAL PLANETS WITH CO₂-RICH ATMOSPHERES

WATER LOSS FROM TERRESTRIAL PLANETS WITH CO₂-RICH ATMOSPHERES

The Role of Water Vapour in Earth’s Energy Flows

The Zugspitze radiative closure experiment for quantifying water vapor absorption over the terrestrial and solar infrared – Part 1: Setup, uncertainty analysis, and assessment of far-infrared water vapor continuum

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The Water Vapour Continuum: Brief History and Recent Developments

Abstract: International audienc

Cited by 120 publications

References 109 publications

WATER LOSS FROM TERRESTRIAL PLANETS WITH CO2-RICH ATMOSPHERES

WATER LOSS FROM TERRESTRIAL PLANETS WITH CO2-RICH ATMOSPHERES

The Role of Water Vapour in Earth’s Energy Flows

The Zugspitze radiative closure experiment for quantifying water vapor absorption over the terrestrial and solar infrared – Part 1: Setup, uncertainty analysis, and assessment of far-infrared water vapor continuum

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Product

Resources

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WATER LOSS FROM TERRESTRIAL PLANETS WITH CO₂-RICH ATMOSPHERES

WATER LOSS FROM TERRESTRIAL PLANETS WITH CO₂-RICH ATMOSPHERES