scholarly journals Spectrum and atmosphere models of irradiated transiting giant planets

2008 ◽  
Vol 4 (S253) ◽  
pp. 239-245
Author(s):  
Ivan Hubeny ◽  
Adam Burrows
Keyword(s):  
Temperature Inversion ◽  
Giant Planets ◽  
Upper Atmosphere ◽  
Planetary Orbit ◽  
Exact Nature ◽  
Thermal Inversion ◽  
Transiting Planets ◽  
Night Flux ◽  
Temperature Inversions

AbstractWe show that a consistent fit to observed secondary eclipse data for several strongly irradiated transiting planets demands a temperature inversion (stratosphere) at altitude. Such a thermal inversion significantly influences the planet/star contrast ratios at the secondary eclipse, their wavelength dependences, and, importantly, the day-night flux contrast during a planetary orbit. The presence of the thermal inversion/stratosphere seems to roughly correlate with the stellar flux at the planet. Such temperature inversions might be caused by an upper-atmosphere absorber whose exact nature is still uncertain.

scholarly journals Methodology for determining multilayered temperature inversions

2015 ◽  
Vol 8 (5) ◽  
pp. 2051-2060 ◽  
Author(s):  
G. J. Fochesatto
Keyword(s):  
Temperature Profile ◽  
Large Scale ◽  
Error Function ◽  
Inversion Layer ◽  
Lower Troposphere ◽  
Temperature Inversion ◽  
Linear Interpolation ◽  
Pollution Dispersion ◽  
Thermal Inversion ◽  
Temperature Inversions

Abstract. Temperature sounding of the atmospheric boundary layer (ABL) and lower troposphere exhibits multilayered temperature inversions specially in high latitudes during extreme winters. These temperature inversion layers are originated based on the combined forcing of local- and large-scale synoptic meteorology. At the local scale, the thermal inversion layer forms near the surface and plays a central role in controlling the surface radiative cooling and air pollution dispersion; however, depending upon the large-scale synoptic meteorological forcing, an upper level thermal inversion can also exist topping the local ABL. In this article a numerical methodology is reported to determine thermal inversion layers present in a given temperature profile and deduce some of their thermodynamic properties. The algorithm extracts from the temperature profile the most important temperature variations defining thermal inversion layers. This is accomplished by a linear interpolation function of variable length that minimizes an error function. The algorithm functionality is demonstrated on actual radiosonde profiles to deduce the multilayered temperature inversion structure with an error fraction set independently.

scholarly journals Atmospheric composition and structure of HD209458b

2008 ◽  
Vol 4 (S253) ◽  
pp. 524-527
Author(s):  
J.-M. Désert ◽  
A. Vidal-Madjar ◽  
A. Lecavelier des Etangs ◽  
D. Sing ◽  
D. Ehrenreich ◽  
...  
Keyword(s):  
Rayleigh Scattering ◽  
Broad Band ◽  
Temperature Inversion ◽  
Upper Atmosphere ◽  
Atmospheric Composition ◽  
Transmission Spectra ◽  
Transiting Planets ◽  
Atmospheric Composition And Structure ◽  
Composition And Structure ◽  
Sodium Abundance

AbstractTransiting planets like HD209458b offer a unique opportunity to scrutinize their atmospheric composition and structure. Transit spectroscopy probes the transition region between the day and night sides, called the limb. We present a re-analysis of existing HST/STIS transmission spectra of HD209458b's atmosphere. From these observations we identify H2 Rayleigh scattering, derive the absolute Sodium abundance and quantify its depletion in the upper atmosphere, extract a stratospheric T-P profile and find a temperature inversion and explain broad band absorptions with the presence of TiO and VO molecules.

scholarly journals Methodology for determining multilayered temperature inversions

2014 ◽  
Vol 7 (10) ◽  
pp. 10559-10583 ◽  
Author(s):  
G. J. Fochesatto
Keyword(s):  
Temperature Profile ◽  
Large Scale ◽  
Thermal Structure ◽  
Error Function ◽  
Inversion Layer ◽  
Meteorological Forcing ◽  
Temperature Variations ◽  
Thermal Inversion ◽  
Upper Level ◽  
Temperature Inversions

Abstract. The atmospheric boundary layer (ABL) exhibit multilayered thermal structure especially in polar atmosphere during extreme winters. These thermal inversions are originated based on the combined forcing of local and large scale synoptic meteorology. At the local scale the thermal inversion layer forms near the surface and plays a central role in controlling the surface radiative cooling; however, depending upon the large scale synoptic meteorological forcing, an upper level thermal inversion can also exist topping the local ABL. In this article a numerical methodology is developed to determine all-thermal inversion layers present in a given temperature profile and deduce some of their thermodynamic properties. The algorithm extract from the temperature profile the most important temperature variations defining thermal layers. This is accomplished by a inear interpolation function of variable length that minimizes an error function. The algorithm functionality is demonstrated on actual radiosonde profiles to deduce all-present inversion layers with an error fraction set independently.

scholarly journals Non-detection of TiO and VO in the atmosphere of WASP-121b using high-resolution spectroscopy

2020 ◽  
Vol 636 ◽  
pp. A117 ◽  
Author(s):  
S. R. Merritt ◽  
N. P. Gibson ◽  
S. K. Nugroho ◽  
E. J. W. de Mooij ◽  
M. J. Hooton ◽  
...  
Keyword(s):  
Correlation Method ◽  
Detection Limits ◽  
Temperature Inversion ◽  
High Resolution Spectroscopy ◽  
Echelle Spectrograph ◽  
Thermal Inversion ◽  
Hot Jupiters ◽  
Very Large Telescope ◽  
Excess Absorption ◽  
Rule Out

Thermal inversions have long been predicted to exist in the atmospheres of ultra-hot Jupiters. However, the detection of two species thought to be responsible – titanium oxide and vanadium oxide – remains elusive. We present a search for TiO and VO in the atmosphere of the ultra-hot Jupiter WASP-121b (Teq ≳ 2400 K), an exoplanet with evidence of VO in its atmosphere at low resolution which also exhibits water emission features in its dayside spectrum characteristic of a temperature inversion. We observed its transmission spectrum with the UV-Visual Echelle Spectrograph at the Very Large Telescope and used the cross-correlation method – a powerful tool for the unambiguous identification of the presence of atomic and molecular species – in an effort to detect whether TiO or VO were responsible for the observed temperature inversion. No evidence for the presence of TiO or VO was found at the terminator of WASP-121b. By injecting signals into our data at varying abundance levels, we set rough detection limits of [VO] ≲−7.9 and [TiO] ≲−9.3. However, these detection limits are largely degenerate with scattering properties and the position of the cloud deck. Our results may suggest that neither TiO or VO are the main drivers of the thermal inversion in WASP-121b; however, until a more accurate line list is developed for VO, we cannot conclusively rule out its presence. Future works will consist of a search for other strong optically-absorbing species that may be responsible for the excess absorption in the red-optical.

Impact of photochemical hazes on the thermal structure of exoplanet atmospheres

2020 ◽  
Author(s):  
Panayotis Lavvas ◽  
Anthony Arfaux
Keyword(s):  
Chemical Composition ◽  
Gas Phase ◽  
Thermal Structure ◽  
Temperature Inversion ◽  
Upper Atmosphere ◽  
Lower Atmosphere ◽  
Cloud Formation ◽  
Electromagnetic Spectrum ◽  
Heating Efficiency ◽  
The Impact

<p>Transit observations reveal that a significant population of the detected exoplanets has hazy atmospheres (Sing et al. 2016). Although the relative contribution of clouds and photochemical aerosols is not yet fully clarified, the impact of haze particles on the thermal structure could be significant, as such particles can efficiently scatter and absorb radiation over a large part of the electromagnetic spectrum. Particularly, photochemical aerosols are anticipated to be present at pressures lower than those of cloud formation. The transit observations of HD 189733 b indicate that the haze opacity responsible for the UV-Visible slope is located at pressures between 1μbar and 1 mbar. As such low pressures, the presence of hazes could allow for strong temperature inversions due to the low atmospheric density. We investigate here the implications of such hazes on the exoplanet atmospheric thermal structure.</p> <p>We simulate the atmospheric thermal structure using a 1D radiative-convective model. The model utilizes non-equilibrium chemical composition results (Lavvas et al. 2014) for the gas phase composition, and haze particle size distributions calculated from an aerosol microphysical growth model (Lavvas & Koskinen 2017, Lavvas et al. 2019). We do not yet consider the non-LTE effects for the gases, but we do take into account the impact of temperature disequilibrium between the particles and the gas envelope that can strongly affect the heating efficiency of the particles. We consider various gas phase opacities from atomic and molecular contributions calculated through correlated-k coefficients.</p> <p>Our results demonstrate that in the lower atmosphere the simulated temperature profiles provide emission spectra that are in good agreement with the eclipse observations for the simulated targets (HD 209458 b and HD 189733 b). In the upper atmosphere of the hazy HD 189733 b the simulated haze distribution, which fits the transit observations, results in a strong temperature inversion. On the contrary, the upper atmosphere of the clear HD 209458 b, is significantly colder compared to previous evaluations based on equilibrium chemistry assumption. The implications of these results on the chemical composition will be discussed, as well as results from other exoplanet cases.</p> <p> </p>

scholarly journals Two Classes of Hot Jupiter Atmospheres

2008 ◽  
Vol 4 (S253) ◽  
pp. 247-253
Author(s):  
Jonathan J. Fortney
Keyword(s):  
Optical Spectra ◽  
Giant Planets ◽  
Potential Importance ◽  
Night Temperature ◽  
Solar Composition ◽  
The Difference ◽  
Temperature Inversions ◽  
Hot Jupiter

AbstractWe highlight the potential importance of gaseous TiO and VO opacity on the highly irradiated close-in giant planets. The day-side atmospheres of these planets may naturally fall into two classes that are somewhat analogous to the M- and L-type dwarfs. Those that are warm enough to have appreciable opacity due to TiO and VO gases we term the “pM Class” planets, and those that are cooler, such that Ti and V are predominantly in solid condensates, we term “pL Class” planets. The optical spectra of pL Class planets are dominated by neutral atomic Na and K absorption. We discuss a connection between temperature inversions and large day/night temperature contrasts for the pM Class planets. Around a Sun-like primary, for solar composition, this boundary likely occurs at ~0.04-0.05 AU, but we discuss important uncertainties. The difference in the observed day/night contrast between υ And b (pM Class) and HD 189733b (pL Class) is naturally explained in this scenario.

scholarly journals Antarctic Low-Tropospheric Humidity Inversions: 10-Yr Climatology

2013 ◽  
Vol 26 (14) ◽  
pp. 5205-5219 ◽  
Author(s):  
Tiina Nygård ◽  
Teresa Valkonen ◽  
Timo Vihma
Keyword(s):  
Water Vapor ◽  
Climate Models ◽  
Weather Prediction ◽  
Temperature Inversion ◽  
Statistical Characteristics ◽  
The Arctic ◽  
Radiosonde Data ◽  
Atmospheric Moisture Budget ◽  
Temperature Inversions ◽  
The Antarctic

Abstract Humidity inversions are nearly permanently present in the coastal Antarctic atmosphere. This is shown based on an investigation of statistical characteristics of humidity inversions at 11 Antarctic coastal stations using radiosonde data from the Integrated Global Radiosonde Archive (IGRA) from 2000 to 2009. The humidity inversion occurrence was highest in winter and spring, and high atmospheric pressure and cloud-free conditions generally increased the occurrence. A typical humidity inversion was less than 200 m deep and 0.2 g kg−1 strong, and a typical humidity profile contained several separate inversion layers. The inversion base height had notable seasonal variations, but generally the humidity inversions were located at higher altitudes than temperature inversions. Roughly half of the humidity inversions were associated with temperature inversions, especially near the surface, and humidity and temperature inversion strengths as well as depths correlated at several stations. On the other hand, approximately 60% of the humidity inversions were accompanied by horizontal advection of water vapor increasing with height, which is also a probable factor supporting humidity inversions. The spatial variability of humidity inversions was linked to the topography and the water vapor content of the air. Compared to previous results for the Arctic, the most striking differences in humidity inversions in the Antarctic were a much higher frequency of occurrence in summer, at least under clear skies, and a reverse seasonal cycle of the inversion height. The results can be used as a baseline for validation of weather prediction and climate models and for studies addressing changes in atmospheric moisture budget in the Antarctic.

scholarly journals Thermosphere and exosphere of hot Jupiters

2008 ◽  
Vol 4 (S253) ◽  
pp. 281-287
Author(s):  
Alain Lecavelier des Etangs
Keyword(s):  
High Altitude ◽  
Theoretical Modeling ◽  
Giant Planets ◽  
Upper Atmosphere ◽  
Escape Rate ◽  
Energy Diagram ◽  
Lyman Alpha ◽  
Hot Jupiters ◽  
First Time ◽  
Very High

AbstractHere we describe the observations and the resulting constraints on the upper atmosphere (thermosphere and exosphere) of hot Jupiters. In particular, observations and theoretical modeling of hot-Jupiter evaporation are described. The observations allowed the discovery that the planet orbiting HD209458 has an extended atmosphere of escaping hydrogen and showed the presence of oxygen and carbon at very high altitude. These observations give unique constraints on the escape rate and mechanism in the atmosphere of these planets. The most recent Lyman-alpha HST observations of HD189733b allow for the first time to compare the evaporation from two different planets in different environments. We present models to quantify the escape rate from the measured occultation depths, and an energy diagram to describe the evaporation state of hot Jupiters. Using this diagram, it is shown that few already known planets could be remnants of former giant planets.

scholarly journals The Climatology of Lower Tropospheric Temperature Inversions in China from Radiosonde Measurements: Roles of Black Carbon, Local Meteorology, and Large-Scale Subsidence

2020 ◽  
Vol 33 (21) ◽  
pp. 9327-9350 ◽  
Author(s):  
Jianping Guo ◽  
Xinyan Chen ◽  
Tianning Su ◽  
Lin Liu ◽  
Youtong Zheng ◽  
...  
Keyword(s):  
Black Carbon ◽  
Large Scale ◽  
North China Plain ◽  
North China ◽  
Temperature Inversion ◽  
Tropospheric Temperature ◽  
The North ◽  
Local Meteorology ◽  
Underlying Mechanisms ◽  
Temperature Inversions

AbstractThe variability of the lower tropospheric temperature inversion (TI) across China remains poorly understood. Using seven years’ worth of high-resolution radiosonde measurements at 120 sites, we compile the climatology of lower tropospheric TI in terms of frequency, intensity, and depth during the period from 2011 to 2017. The TI generally exhibits strong seasonal and geographic dependencies. Particularly, the TI frequency is found to be high in winter and low in summer, likely due to the strong aerosol radiative effect in winter. The frequency of the surface-based inversion (SBI) exhibits a “west low, east high” pattern at 0800 Beijing time (BJT), which then switches to “west high, east low” at 2000 BJT. Both the summertime SBI and elevated inversion (EI) reach a peak at 0800 BJT and a trough at 1400 BJT. Interestingly, the maximum wintertime EI frequency occurs over Southeast China (SEC) rather than over the North China Plain (NCP), likely attributable to the combination of the heating effect of black carbon (BC) originating from the NCP, along with the strong subsidence and trade inversion in SEC. Correlation analyses between local meteorology and TI indicate that larger lower tropospheric stability (LTS) favors more frequent and stronger TIs, whereas the stronger EI under smaller LTS conditions (unstable atmosphere) is more associated with subsidence rather than BC. Overall, the spatial pattern of the lower tropospheric TI and its variability in China are mainly controlled by three factors: local meteorology, large-scale subsidence, and BC-induced heating. These findings help shed some light on the magnitude, spatial distribution, and underlying mechanisms of the lower tropospheric TI variation in China.

scholarly journals Analysis of temperature inversions during periods of adverse weather conditions in Krasnoyarsk in the winter period of 2019-2020

2020 ◽  
Vol 223 ◽  
pp. 03021
Author(s):  
Alexander Dergunov ◽  
Oleg Yakubailik
Keyword(s):  
Particulate Matter ◽  
Weather Conditions ◽  
Temperature Inversion ◽  
Reanalysis Data ◽  
Winter Period ◽  
Meteorological Model ◽  
Adverse Weather Conditions ◽  
Adverse Weather ◽  
Temperature Inversions ◽  
High Degree

The work is devoted to the search for relationships between the pollution of the atmosphere of Krasnoyarsk by particulate matter and temperature inversion – an increase in temperature with height in the surface layer of the atmosphere. The research is based on reanalysis data of the NASA GFS meteorological model for air temperature at different altitudes of the atmosphere and the results of measurements of concentrations of particulate matter in the air monitoring system of the FRC KSC SB RAS, as well as information about officially declared periods of adverse weather conditions. The results obtained allow us to conclude that there is a high degree of correlation between these values, and that it is possible to use the GFS model data to predict the environmental situation.

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