A round Earth for climate models

Prather, Michael J.; Hsu, Juno

doi:10.1073/pnas.1908198116

Cited by 8 publications

(8 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The plane‐parallel assumption treats atmospheric layers as flat slabs rather than spherical shells. A spherical atmosphere intercepts 2.5 W m −2 more radiation and heats the atmosphere by 1.5 W m −2 in the global‐annual mean relative to the plane parallel atmosphere commonly used in ESMs (Prather & Hsu, 2019). This effect is especially strong in polar latitudes where solar zenith angles are larger, where our study shows spectrally resolved albedo has the greatest impact.…”

Section: Discussionmentioning

confidence: 99%

Surface and Atmospheric Heating Responses to Spectrally Resolved Albedo of Frozen and Liquid Water Surfaces

Tolento,

Zender,

Whicker‐Clarke

2024

JGR Atmospheres

View full text Add to dashboard Cite

Multiple Earth system models (ESMs) discretize surface albedo into two semi‐broadbands comprising the UV/visible and near‐infrared (NIR) wavelengths. Here, we use an offline single‐column radiative transfer model to investigate the radiative effects of spectrally resolving the surface albedo. We use the Snow, Ice, and Aerosol Radiative model, extended to simulate liquid water, to calculate snow, ice, and liquid water albedo. We flux‐weight the hyperspectral albedo into the coarser spectral bands used by the atmospheric shortwave radiative transfer model. We establish representative atmospheric profiles for the three surface types and compare their shortwave fluxes and atmospheric warming rates with the spectrally resolved albedo to those calculated with the semi‐broadband approximation. Spectrally resolved surface albedo over snow and ice reduces atmospheric warming by darkening the albedo of NIR bands, correcting the too‐strong surface absorption in visible bands, and too‐weak surface absorption in shortwave infrared bands caused by the semi‐broadband approximation. We explore the effects on surface and atmospheric warming rates of varying solar zenith angle, cloud cover, relative humidity, and snow grain/air bubble radii. The semi‐broadband albedo biases can exceed 10% and 2% for the surface and atmospheric net flux respectively, being particularly strong under conditions which alter the distributions of surface insolation (i.e., cloud cover or increased atmospheric water vapor). These results show that transmitting a higher resolution spectral radiation field between the atmosphere and surface reduces biases in surface absorption and atmospheric heating present in ESMs that currently use the semi‐broadband approximation.

show abstract

Section: Discussionmentioning

confidence: 99%

Surface and Atmospheric Heating Responses to Spectrally Resolved Albedo of Frozen and Liquid Water Surfaces

Tolento,

Zender,

Whicker‐Clarke

2024

JGR Atmospheres

View full text Add to dashboard Cite

show abstract

“…Generally, the surface temperature has been assumed to be 15°C which is not the same as the measurement-based Es values of the Earth. Prather and Hsu [16] have found that the Earth receives 1.5 Wm -2 more insolation energy than in the climate models. This is since the Earth is a spherical object, but the climate models are based on the flat Earth model.…”

Section: Dependency Of Emitted and Absorbed Fluxesmentioning

confidence: 98%

The Greenhouse Effect Calculations by an Iteration Method and the Issue of Stratospheric Cooling

Ollila

2020

PSIJ

View full text Add to dashboard Cite

The anthropogenic global warming theory is based on the greenhouse effect (GH), which is due to the longwave (LW) absorption by GH gases and clouds according to the IPCC. This LW radiation downward is the imminent cause for the GH effect increasing the surface temperature by 33°C. It has been shown that latent and sensible heating are essential parts of downward LW radiation and the total GH effect. In this study, an iteration method utilizing this basic GH effect mechanism has been applied to simulate the warming impacts of enhanced GH effect changes. The results are compatible with the Transient Climate Response (TCR) of 0.6°C. The issue of stratospheric cooling due to increased CO2 concentration has been calculated and analyzed. The stratospheric cooling effect is real but its impact on the Effective Radiative Forcing (ERF) has been shown to be negative and not positive as generally implied. The reason is that the decreased absorption of LW radiation in the atmosphere always decreases the GH effect. This result challenges the new concept of the ERF that is the sum of Instantaneous RF (IRF) and rapid adjustments as applied in General Climate Models (GCMs). If the stratospheric adjustment has the opposite effect, then the IRF values would be also wrongly calculated in these models. Two independent validation methods were applied to test the temperature impacts of CO2 concentration increases.

show abstract

“…The solar heating module Solar‐J (Hsu et al., 2017; hence H2017) is embedded in our chemistry‐transport model (CTM) and used to integrate climate‐relevant heating rates using the European Center's Integrated Forecast System meteorological data that drives the CTM simulation of atmospheric chemistry (M. J. Prather et al., 2017; Szépszó et al., 2019). This CTM + Solar‐J model quantified the errors related to spherical geometry of the atmosphere (M. J. Prather & Hsu, 2019; hence P2019). Here, we use that code and diagnostic framework (i.e., January average of hourly global calculations at horizontal resolution of 1.1° including water vapor and ice‐/liquid‐water clouds) for an extensive set of case studies.…”

Section: Introductionmentioning

confidence: 99%

“…This CTM + Solar-J model quantified the errors related to spherical geometry of the atmosphere (M. J. Prather & Hsu, 2019; hence P2019). Here, we use that code and diagnostic framework (i.e., January average of hourly global calculations at horizontal resolution of 1.1° including water vapor and ice-/liquid-water clouds) for an extensive set of case studies.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Assessing Uncertainties and Approximations in Solar Heating of the Climate System

Hsu

Prather

2021

J Adv Model Earth Syst

Self Cite

View full text Add to dashboard Cite

The heat from sunlight drives the weather and climate system, the energy in solar photons drives atmospheric chemistry, and the photosynthetically active radiation drives life. For Earth system models (ESMs), one needs to calculate the scattering, absorption, and reflection of solar radiation throughout the atmosphere, ocean, cryosphere, and land surface. The idealized radiative transfer (RT) problem is well known and in many cases has near-exact, but costly solutions; whereas the atmospheric physics of the problem involving gases, clouds, aerosols and surface properties includes unknowns that cause a fundamental uncertainty in the solution. One motivation for this study is to evaluate the potential improvements in solar heating rates if more accurate physics or RT codes are used, but the overriding motivation is to assess a wide range of approximations and uncertainties within a single climate-relevant framework. Where more accurate physics or numerical solutions are known, we can estimate the error in current RT codes, and where there is fundamental uncertainty, we can estimate the potential for error using different methods for framing the problem. The solar heating module Solar-J (Hsu et al., 2017; hence H2017) is embedded in our chemistry-transport model (CTM) and used to integrate climate-relevant heating rates using the European Center's Integrated

show abstract

A round Earth for climate models

Cited by 8 publications

References 42 publications

Surface and Atmospheric Heating Responses to Spectrally Resolved Albedo of Frozen and Liquid Water Surfaces

Surface and Atmospheric Heating Responses to Spectrally Resolved Albedo of Frozen and Liquid Water Surfaces

The Greenhouse Effect Calculations by an Iteration Method and the Issue of Stratospheric Cooling

Assessing Uncertainties and Approximations in Solar Heating of the Climate System

Contact Info

Product

Resources

About