Rapid calculation of radiative heating rates and photodissociation rates in inhomogeneous multiple scattering atmospheres

Toon, O. B.; McKay, C. P.; Ackerman, Thomas P.; Santhanam, Keshav

doi:10.1029/jd094id13p16287

Cited by 909 publications

(852 citation statements)

References 30 publications

Supporting

Mentioning

837

Contrasting

Unclassified

Order By: Relevance

“…[4] Snowpack heating and reflectance are predicted with our two-stream, multi-layer SNow, ICe, and Aerosol Radiation model (SNICAR), based on Wiscombe and Warren [1980] and Toon et al [1989]. The present study neglects aerosol effects.…”

Section: Methodsmentioning

confidence: 99%

Snowpack radiative heating: Influence on Tibetan Plateau climate

Flanner

Zender

2005

Geophysical Research Letters

171

169

View full text Add to dashboard Cite

[1] Solar absorption decays exponentially with depth in snowpacks. However, most climate models constrain all snowpack absorption to occur uniformly in the top-most snow layer. We show that 20-45% of solar absorption by deep snowpacks occurs more than 2 cm beneath the surface. Accounting for vertically-resolved solar heating alters steady-state snow mass without changing bulk snow albedo, and ice-albedo feedback amplifies this effect. Vertically-resolved snowpack heating reduces winter snow mass on the Tibetan Plateau by 80% in one GCM, and significantly increases 2 m air temperature. These changes significantly reduce model-measurement discrepancies. Our results demonstrate that snowpack radiative heating plays a significant role in regulating surface climate and hydrology. More accurate snowpack radiation has the potential to improve predictions of related climate processes, such as spring runoff and the Asian Monsoon.

show abstract

Section: Methodsmentioning

confidence: 99%

Snowpack radiative heating: Influence on Tibetan Plateau climate

Flanner

Zender

2005

Geophysical Research Letters

171

169

View full text Add to dashboard Cite

show abstract

“…It was significantly revised to model the atmospheres of brown dwarfs (Marley et al, 1996;Burrows et al, 1997;Marley et al, 2002), Uranus (Marley & McKay, 1999), cool EGPs (Marley, 1998), and "Hot Jupiters" (Fortney et al, 2005). The basic radiative transfer solving scheme was developed by Toon et al (1989).…”

Section: Atmosphere Modelsmentioning

confidence: 99%

“…They also tested various initial conditions on their own models and find that the cooling tracks differ significantly at young ages (less than ∼5 Myr), which could lead to very different mass or age estimates, based on the luminosity of a given object, or group of objects. Wuchterl & Tscharnuter (2003) have published formation models of stars and brown dwarfs down to 50 M J . These models follow the collapse of an initial cloud all the way to the main sequence, while making the minimum number of a priori assumptions.…”

Section: Introductionmentioning

confidence: 99%

Young Jupiters are faint: new models of the early evolution of giant planets

Fortney¹,

Marley

Hubickyj

et al. 2005

Astron Nachr

View full text Add to dashboard Cite

Abstract.Here we show preliminary calculations of the cooling and contraction of a 2 MJ planet. These calculations, which are being extended to 1-10 MJ, differ from other published "cooling tracks" in that they include a core accretion-gas capture formation scenario, the leading theory for the formation of gas giant planets. We find that the initial post-accretionary intrinsic luminosity of the planet is ∼3 times less than previously published models which use arbitrary initial conditions. These differences last a few tens of millions of years. Young giant planets are intrinsically fainter than has been previously appreciated. We also discuss how uncertainties in atmospheric chemistry and the duration of the formation time of giant planets lead to challenges in deriving planetary physical properties from comparison with tabulated model values.

show abstract

“…Longwave and shortwave radiative fluxes and heating rates are calculated with a two-stream code [Toon et al, 1989b] coupled to the model. Ice crystal singlescattering properties are calculated with a Mie scattering code.…”

Section: Simulations Of Freeze-drying Drivenmentioning

confidence: 99%

A conceptual model of the dehydration of air due to freeze‐drying by optically thin, laminar cirrus rising slowly across the tropical tropopause

Jensen¹,

Pfister²,

Ackerman³

et al. 2001

J. Geophys. Res.

Self Cite

111

106

View full text Add to dashboard Cite

Abstract.In this study, we use a cloud model to simulate dehydration which occurs due to formation of optically thin, laminar cirrus as air rises slowly across the tropopause. The slow ascent and adiabatic cooling, which balances the radiative heating near the tropopause, drives nucleation of a very small number of ice crystals (< 1 L -•).These crystals grow rapidly and sediment out within a few hours. The clouds never become optically thick enough to be visible from the ground. The ice crystal nucleation and growth prevents the relative humidity with respect to ice (RHI) from rising more than a few percent above the threshold for ice nucleation (RHI•uc m110-160%, depending upon the aerosol composition); hence, laminar cirrus can limit the mixing ratio of water vapor entering the stratosphere. However, the ice number densities are too low and their sedimentation is too rapid to allow dehydration of the air from RHI•c down to saturation (RHI = 100%). The net result is that air crosses the tropopause with water vapor mixing ratios about 1.1 to 1.6 times the ice saturation mixing ratio corresponding to the tropopause temperature, depending on the threshold of ice nucleation on aerosols in the tropopause region. If the cross-tropopause ascent rate is larger than that calculated to balance radiative heating (0.2 cm s -1), then larger ice crystal number densities are generated, and more effective dehydration is possible (assuming a fixed temperature). The water vapor mixing ratio entering the stratosphere decreases with increasing ascent rate (approaching the tropopause ice saturation mixing ratio) until the vertical wind speed exceeds the ice crystal terminal velocity (about 10 cm s-L). More effective dehydration can also be provided by temperature oscillations associated with wave motions. The water vapor mixing ratio entering the stratosphere is essentially controlled by the tropopause temperature at the coldest point in the wave. Hence, the efiSciency of dehydration at the tropopause depends upon both the effectiveness of upper tropospheric aerosols as ice nuclei and the occurrence of wave motions in the tropopause region. In situ humidity observations from tropical aircraft campaigns and balloon launches over the past several years have provided a few examples of ice-supersaturated air near the tropopause. However, given the scarcity of date[ and the uncertainties in water vapor measurements, we lack definitive evidence that air entering the stratosphere is supersaturated with respect to ice.

show abstract

Rapid calculation of radiative heating rates and photodissociation rates in inhomogeneous multiple scattering atmospheres

Cited by 909 publications

References 30 publications

Snowpack radiative heating: Influence on Tibetan Plateau climate

Snowpack radiative heating: Influence on Tibetan Plateau climate

Young Jupiters are faint: new models of the early evolution of giant planets

A conceptual model of the dehydration of air due to freeze‐drying by optically thin, laminar cirrus rising slowly across the tropical tropopause

Contact Info

Product

Resources

About