scholarly journals Saturn's Atmospheric Temperature Structure and Heat Budget

2014 ◽  
pp. 5871-5881
Author(s):  
Glenn S. Orton ◽  
Andrew P. Ingersoll
Keyword(s):  
Heat Budget ◽  
Atmospheric Temperature ◽  
Temperature Structure

scholarly journals Observing the climate impact of large wildfires on stratospheric temperature

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Matthias Stocker ◽  
Florian Ladstädter ◽  
Andrea K. Steiner
Keyword(s):  
Lower Stratosphere ◽  
Volcanic Eruptions ◽  
Satellite Observation ◽  
Atmospheric Temperature ◽  
Climate Impact ◽  
Atmospheric Composition ◽  
Temperature Structure ◽  
Climate Trends ◽  
Short Term ◽  
Climate Signal

AbstractWildfires are expected to become more frequent and intense in the future. They not only pose a serious threat to humans and ecosystems, but also affect Earth’s atmosphere. Wildfire plumes can reach into the stratosphere, but little is known about their climate impact. Here, we reveal observational evidence that major wildfires can have a severe impact on the atmospheric temperature structure and short-term climate in the stratosphere. Using advanced satellite observation, we find substantial warming of up to 10 K of the lower stratosphere within the wildfire plumes during their early development. The short-term climate signal in the lower stratosphere lasts several months and amounts to 1 K for the Northern American wildfires in 2017, and up to striking 3.5 K for the Australian wildfires in 2020. This is stronger than any signal from recent volcanic eruptions. Such extreme events affect atmospheric composition and climate trends, underpinning their importance for future climate.

scholarly journals A Coupled Cloud Physics–Radiation Parameterization of the Bulk Optical Properties of Cirrus and Its Impact on the Met Office Unified Model Global Atmosphere 5.0 Configuration

2014 ◽  
Vol 27 (20) ◽  
pp. 7725-7752 ◽  
Author(s):  
Anthony J. Baran ◽  
Peter Hill ◽  
Kalli Furtado ◽  
Paul Field ◽  
James Manners
Keyword(s):  
Optical Properties ◽  
Atmospheric Temperature ◽  
Unified Model ◽  
Crystal Habit ◽  
Temperature Structure ◽  
Ice Crystal ◽  
Cloud Physics ◽  
Shape Distribution ◽  
Temperature Bias ◽  
Ice Water

Abstract A new coupled cloud physics–radiation parameterization of the bulk optical properties of ice clouds is presented. The parameterization is consistent with assumptions in the cloud physics scheme regarding particle size distributions (PSDs) and mass–dimensional relationships. The parameterization is based on a weighted ice crystal habit mixture model, and its bulk optical properties are parameterized as simple functions of wavelength and ice water content (IWC). This approach directly couples IWC to the bulk optical properties, negating the need for diagnosed variables, such as the ice crystal effective dimension. The parameterization is implemented into the Met Office Unified Model Global Atmosphere 5.0 (GA5) configuration. The GA5 configuration is used to simulate the annual 20-yr shortwave (SW) and longwave (LW) fluxes at the top of the atmosphere (TOA), as well as the temperature structure of the atmosphere, under various microphysical assumptions. The coupled parameterization is directly compared against the current operational radiation parameterization, while maintaining the same cloud physics assumptions. In this experiment, the impacts of the two parameterizations on the SW and LW radiative effects at TOA are also investigated and compared against observations. The 20-yr simulations are compared against the latest observations of the atmospheric temperature and radiative fluxes at TOA. The comparisons demonstrate that the choice of PSD and the assumed ice crystal shape distribution are as important as each other. Moreover, the consistent radiation parameterization removes a long-standing tropical troposphere cold temperature bias but slightly warms the southern midlatitudes by about 0.5 K.

scholarly journals An Alternative Bias Correction Scheme for CrIS Data Assimilation in a Regional Model

2019 ◽  
Vol 147 (3) ◽  
pp. 809-839 ◽  
Author(s):  
Xin Li ◽  
Xiaolei Zou ◽  
Mingjian Zeng
Keyword(s):  
Data Assimilation ◽  
Bias Correction ◽  
Moving Average ◽  
Atmospheric Temperature ◽  
Lapse Rate ◽  
Specific Humidity ◽  
Convective Precipitation ◽  
Temperature Structure ◽  
The Impact ◽  
Mean Square Errors

Bias correction (BC) is a crucial step for satellite radiance data assimilation (DA). In this study, the traditional airmass BC scheme in the National Centers for Environmental Prediction (NCEP) Gridpoint Statistical Interpolation (GSI) is investigated for Cross-track Infrared Sounder (CrIS) DA. The ability of the airmass predictors to model CrIS biases is diagnosed. Correlations between CrIS observation-minus-background ( O − B) samples and the two lapse rate–related airmass predictors employed by GSI are found to be very weak, indicating that the bias correction contributed by the airmass BC scheme is small. A modified BC scheme, which directly calculates the moving average of O − B departures from data of the previous 2 weeks with respect to scan position and latitudinal band, is proposed and tested. The impact of the modified BC scheme on CrIS radiance DA is compared with the variational airmass BC scheme. Results from 1-month analysis/forecast experiments show that the modified BC scheme removes nearly all scan-dependent and latitude-dependent biases, while residual biases are still found in some channels when the airmass BC scheme is applied. Smaller predicted root-mean-square errors of temperature and specific humidity and higher equivalent threat scores are obtained by the DA experiment using the modified BC scheme. If O − B samples are replaced by observation-minus-analysis ( O − A) samples for bias estimates in the modified BC scheme, the forecast impacts are reduced but remain positive. A convective precipitation case that occurred on 21 August 2016 is investigated. Using the modified BC scheme, the atmospheric temperature structure and the geopotential height structures near trough/ridge areas are better resolved, resulting in better precipitation forecasts.

scholarly journals ATMOSPHERIC STRUCTURE OF THE OUTER PLANETS FROM THERMAL EMISSION DATA

1981 ◽  
Vol 96 ◽  
pp. 35-56
Author(s):  
Glenn S. Orton
Keyword(s):  
Chemical Composition ◽  
Thermal Emission ◽  
Atmospheric Temperature ◽  
Temperature Structure ◽  
Emission Data ◽  
Outer Planets ◽  
Atmospheric Structure ◽  
Stratospheric Temperature ◽  
Aerosol Absorption ◽  
Show Evidence

Determination of atmospheric temperature structure is of paramount importance to the understanding of planetary atmospheric structure. The most powerful methods for determining atmospheric structure exploit the opacities provided by the collision induced H2 dipole and the ν4 fundamental of CH4. In addition to earth-based observations, useful measurements of thermal emission from Jupiter and Saturn have been or soon will be made by several spacecraft, with results cross-checked with independent radio occultation results. For Uranus and Neptune, only a limited set of whole-disk earth-based data exists. All the outer planets show evidence for stratospheric temperature inversions; temperature minima range from about 105 K for Jupiter and 87 K for Saturn, to roughly 55 K for Uranus and Neptune. In addition to better data, remaining problems may be resolved by better quantitative understanding of gas and aerosol absorption and scattering properties, chemical composition, and non-LTE source functions. Ultimately, temperature structure results must be supplemented by quantitative energy equilibrium models which will allow some meaning to be given to the relationships between such characteristics as temperature, clouds, incident solar and planetary radiation, and chemical composition.

scholarly journals A new set of atmosphere and evolution models for cool T–Y brown dwarfs and giant exoplanets

2020 ◽  
Vol 637 ◽  
pp. A38 ◽  
Author(s):  
M. W. Phillips ◽  
P. Tremblin ◽  
I. Baraffe ◽  
G. Chabrier ◽  
N. F. Allard ◽  
...  
Keyword(s):  
Near Infrared ◽  
Vertical Mixing ◽  
Emission Spectra ◽  
Brown Dwarfs ◽  
Atmospheric Temperature ◽  
Temperature Structure ◽  
Surface Boundary ◽  
Quantum Molecular Dynamics ◽  
Solar Metallicity ◽  
The Impact

We present a new set of solar metallicity atmosphere and evolutionary models for very cool brown dwarfs and self-luminous giant exoplanets, which we term ATMO 2020. Atmosphere models are generated with our state-of-the-art 1D radiative-convective equilibrium code ATMO, and are used as surface boundary conditions to calculate the interior structure and evolution of 0.001–0.075 M⊙ objects. Our models include several key improvements to the input physics used in previous models available in the literature. Most notably, the use of a new H–He equation of state including ab initio quantum molecular dynamics calculations has raised the mass by ~1−2% at the stellar–substellar boundary and has altered the cooling tracks around the hydrogen and deuterium burning minimum masses. A second key improvement concerns updated molecular opacities in our atmosphere model ATMO, which now contains significantly more line transitions required to accurately capture the opacity in these hot atmospheres. This leads to warmer atmospheric temperature structures, further changing the cooling curves and predicted emission spectra of substellar objects. We present significant improvement for the treatment of the collisionally broadened potassium resonance doublet, and highlight the importance of these lines in shaping the red-optical and near-infrared spectrum of brown dwarfs. We generate three different grids of model simulations, one using equilibrium chemistry and two using non-equilibrium chemistry due to vertical mixing, all three computed self-consistently with the pressure-temperature structure of the atmosphere. We show the impact of vertical mixing on emission spectra and in colour-magnitude diagrams, highlighting how the 3.5−5.5 μm flux window can be used to calibrate vertical mixing in cool T–Y spectral type objects.

Satellite measurements of middle atmosphere temperature structure

1980 ◽  
Vol 296 (1418) ◽  
pp. 41-57 ◽  
Keyword(s):  
Lower Stratosphere ◽  
Middle Atmosphere ◽  
Atmospheric Temperature ◽  
Temperature Structure ◽  
Satellite Measurements ◽  
Strong Negative Correlation ◽  
Mesospheric Temperature ◽  
Wide Range ◽  
Atmosphere Temperature ◽  
Instruments And Techniques

Sixteen years have elapsed since the first satellite measurements of atmospheric temperature. These were observations of the lower stratosphere. Techniques have developed rapidly, and observations now extend from the surface to the mesopause. The instruments and techniques are briefly described and a review is given of the wide range of middle atmosphere research that has been based upon these measurements. The Nimbus 6 pressure modulator radiometer has made over 3 years’ observations of upper stratospheric and mesospheric temperature, with weighting functions peaking at up to 80 km. The main results from this instrument and their relation to variations at lower levels are discussed. Temperature variations are generally smaller in the upper mesosphere than in the stratosphere. Planetary waves penetrate to this level in winter. There is a strong negative correlation between zonal mean temperature near the mesopause and in the upper stratosphere on both long and short timescales.

Middle atmospheric temperature structure over two tropical locations, Chung Li (25°N,121°E) and Gadanki (13.5°N,79.2°E)

2002 ◽  
Vol 64 (12-14) ◽  
pp. 1311-1319 ◽  
Author(s):  
J.B Nee ◽  
S Thulasiraman ◽  
W.N Chen ◽  
M Venkat Ratnam ◽  
D Narayana Rao
Keyword(s):  
Atmospheric Temperature ◽  
Temperature Structure

scholarly journals Declining Aerosols in CMIP5 Projections: Effects on Atmospheric Temperature Structure and Midlatitude Jets

2014 ◽  
Vol 27 (18) ◽  
pp. 6960-6977 ◽  
Author(s):  
Leon D. Rotstayn ◽  
Emily L. Plymin ◽  
Mark A. Collier ◽  
Olivier Boucher ◽  
Jean-Louis Dufresne ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
Temperature Response ◽  
Coupled Model ◽  
Atmospheric Temperature ◽  
Temperature Structure ◽  
Tropospheric Temperature ◽  
Anthropogenic Aerosols ◽  
Aerosol Radiative Forcing ◽  
The Tropics ◽  
Aerosol Radiative

Abstract The effects of declining anthropogenic aerosols in representative concentration pathway 4.5 (RCP4.5) are assessed in four models from phase 5 the Coupled Model Intercomparison Project (CMIP5), with a focus on annual, zonal-mean atmospheric temperature structure and zonal winds. For each model, the effect of declining aerosols is diagnosed from the difference between a projection forced by RCP4.5 for 2006–2100 and another that has identical forcing, except that anthropogenic aerosols are fixed at early twenty-first-century levels. The response to declining aerosols is interpreted in terms of the meridional structure of aerosol radiative forcing, which peaks near 40°N and vanishes at the South Pole. Increasing greenhouse gases cause amplified warming in the tropical upper troposphere and strengthening midlatitude jets in both hemispheres. However, for declining aerosols the vertically averaged tropospheric temperature response peaks near 40°N, rather than in the tropics. This implies that for declining aerosols the tropospheric meridional temperature gradient generally increases in the Southern Hemisphere (SH), but in the Northern Hemisphere (NH) it decreases in the tropics and subtropics. Consistent with thermal wind balance, the NH jet then strengthens on its poleward side and weakens on its equatorward side, whereas the SH jet strengthens more than the NH jet. The asymmetric response of the jets is thus consistent with the meridional structure of aerosol radiative forcing and the associated tropospheric warming: in the NH the latitude of maximum warming is roughly collocated with the jet, whereas in the SH warming is strongest in the tropics and weakest at high latitudes.

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