Clouds Archives

Conceptual model of shallow cumulus cloud evolution during a solar eclipse The time progresses in the horizontal direction to the right. Background color shading indicates the virtual potential temperature of the atmosphere and land surface in our simulation. The red and blue arrows are the sensible and latent heat fluxes, respectively, which depend strongly on the temperature difference between the surface and the atmosphere just above the surface. The yellow arrows represent the amount of incoming solar radiation, which is largest around noon but is reduced during a solar eclipse as illustrated by the lunar disk covering the solar disk. When the growing atmospheric boundary layer height (dotted line) intersects with the lifting condensation level (dashed line), clouds are formed, but they are diminished when the updrafts are slowed down during a solar eclipse, as indicated by the smaller inclination of the black arrow. -- astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Gaia - Planetary Perspectives, Space Weather & Heliophysics, Status Report, Terraforming & Geoengineering

Terraforming / Geoengineering: Clouds Dissipate Quickly During Solar Eclipses As The Land Surface Cools

by Keith CowingJune 1, 2024

Clouds affected by solar eclipses could influence the reflection of sunlight back into space and might change local precipitation patterns.

Polarization of planetary phase functions for the cases of two cloud cap configurations and for a cloud-free atmosphere to illustrate the effect of locally obscured limb polarization on the net phase function at wavelengths of 𝜆 = 550 nm. The three panels show the spatially resolved normalized Stokes parameters 𝑞(𝛼) and 𝑢(𝛼) for selected phase angles 𝛼 of spatially resolved planetary disks. -- astro-ph.EP

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Mapping, Geodesy, Cartography, Bathymetry, Status Report, Stellar Cartography

Feasibility Study on Retrieving Exoplanetary Cloud Cover Distributions Using Polarimetry

by Keith CowingMay 22, 2024May 22, 2024

Context. As a new growing field, exocartography aims to map the surface features of exoplanets that are beyond the resolution of traditional observing techniques. While photometric approaches have been discussed […]

Curated JWST ERS transmission data of WASP-39b from the following four instruments: NIRCam (blue), NIRISS (red), NIRSpec G395H (green), and NIRSpec PRISM (yellow). The data were originally published by Ahrer et al. (2023b), Feinstein et al. (2023), Rustamkulov et al. (2023), and Alderson et al. (2023), respectively. -- astro-ph.EP

Astrochemistry, Astrogeology, Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

Information Content of JWST Spectra of WASP-39b

by Keith CowingMay 7, 2024May 7, 2024

WASP-39b was observed using several different JWST instrument modes and the spectra were published in a series of papers by the ERS team.

Terminal velocity of liquid droplets as a function of particle size and altitude for terrestrial conditions of gravity, temperature, and air composition. The red solid line indicates a Reynolds Number of 0.1. The black dashed lines indicate the time to fall through one of our 200 m–thick vertical levels: τ = 5 s, τ = 4000 s, and τ = 106 s. -- astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biophysics, Habitable Zones, Status Report, Water/Hycean Worlds & Oceanography

Impact of Planetary Parameters on Water Clouds Microphysics

by Keith CowingMay 7, 2024May 7, 2024

Potentially habitable exoplanets are targets of great interest for the James Webb Space Telescope and upcoming mission concepts such as the Habitable Worlds Observatory. Clouds strongly affect climate and habitability, […]

SVD/PCA based detrending process and the effect of model reprocessing for order number 11 of Night 1 of CARMENES observation. (a) Data after calibration through CARACAL, (b) After SVD/PCA based detrending and strong residual masking - the orange line shows the cross-section along which the spectra for (e) is drawn, (c) Nominal exoplanet model signal that is to be injected into noiseless data matrix before reprocessing - the black line represents the cross-section for drawing the spectrum in (f), (d) Reprocessed model signal showing the model signal + artefacts in the out-of-transit phases - blue is the cross-section for drawing (g) and reddish brown for (h), (e) Cross-section at mid-transit time (Phase = 0) for the processed and normalised data in (b) showing variations around 1.0, (f) Same as (e) but for the nominal model signal in (c), (g) Same as (e) but for the reprocessed model signal in (d). The differences between (f) and (g) notably in the line depths and wing shapes illustrate the effect of the SVD/PCA based detrending procedure on the the model signal and by definition any actual signal that would be present in the data, (h) Cross-section at an out-of-transit time (Phase ≈ 0.02) showcasing the nature of the artefacts caused due to model reprocessing with a similar scale as in (g). -- astro-ph.EP

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

Constraints On Atmospheric Water Abundance and Cloud Deck Pressure in the Warm Neptune GJ 3470 b via CARMENES Transmission Spectroscopy

by Keith CowingApril 11, 2024April 11, 2024

Observations of cooler atmospheres of super-Earths and Neptune sized objects often show flat transmission spectra.

Comparison of 12CH4 cross-sections at 296 K in the far and mid-infrared regions for different databases: MeCaSDa (Ba et al. 2013), TheoReTs (Rey et al. 2016b), the ExoMol MM line list (Yurchenko et al. 2024a), HITRAN2020 (Gordon et al. 2022) and HITEMP (Hargreaves et al. 2020). -- astro-ph.IM

AI - Data - Apps - Cybernetics, Ariel Mission, Astronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

Data Availability And Requirements Relevant For The Ariel Space Mission And Other Exoplanet Atmosphere Applications

by Keith CowingApril 3, 2024October 16, 2024

The goal of this white paper is to provide a snapshot of the data availability and data needs primarily for the Ariel space mission, but also for related atmospheric studies […]

Color time series comparison to composite Y + J + H + K light curve (gray). Shaded regions are 1σ uncertainty. Vertical dashed lines denote color series and light curve minima. Qualitatively, it can be seen that composite light curve minima correspond to reddening (i.e. low flux in Y − J, J − H, and H − K corresponds to redder color indices). This provides evidence for cloud scattering (see §5.3). Light curve maxima correspond to bluer, presumably relatively cloud-free regions. The Y − J and J − H color series are approximately in phase but the H − K solution is ∼90◦ out of phase with the remaining color series, offering evidence of SIMP0136’s complex vertical cloud structure. -- astro-ph.EP

Atmospheres, Climate, Weather, Brown Dwarfs, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

Atmospheric Waves Driving Variability and Cloud Modulation on a Planetary-Mass Object

by Keith CowingMarch 11, 2024March 11, 2024

Planetary-mass objects and brown dwarfs at the transition from relatively red L dwarfs to bluer mid-T dwarfs (Teff∼1300 K) show enhanced spectrophotometric variability.

Left: seasonal variation of the temperature, which is defined by the difference between the Northern Hemisphere (NH) averaged surface temperature and the global annual mean surface temperature. Middle: the maximum streamfunction in NH. Right: The latitude of the maximum zonal mean precipitation (ITCZ). The filled shaded contours represent the results from no-cloud simulations and the values are shown in the colourbars, while the open contours represent the results from cloud simulations and the values are shown in inline labels. For comparison, the contours are plotted at the same levels for no-clouds and clouds simulations. To highlight the difference in seasonal transition, the zero contour lines are bold black (clouds) and gray (no-clouds) for the left and right panels. The contours of streamfunction and ITCZ latitude are smoothed by a Gaussian filter with a standard deviation of σ = 3 days. The horizontal lines represent day of vernal equinox (day 90), northern summer solstice (day 180), and autumnal equinox (day 270), and day 0 is northern winter solstice. The vertical lines represent rotation rates of Ω∗ = 1/8 and 1. -- physics.ao-ph

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Status Report, Water/Hycean Worlds & Oceanography

Clouds And Seasonality On Terrestrial Planets With Varying Rotation Rates

by Keith CowingFebruary 12, 2024February 11, 2024

Using an idealised climate model incorporating seasonal forcing, we investigate the impact of rotation rate on the abundance of clouds on an Earth-like aquaplanet, and the resulting impacts upon albedo […]

An artist's concept of the exoplanet GJ 9827d, the smallest exoplanet where water vapor has been detected in the atmosphere. CREDIT NASA/ESA/Leah Hustak, Ralf Crawford, Space Telescope Science Institute

Astronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Neptune, Press Release, Uranus

Neptune-like Exoplanets Can Be Cloudy Or Clear — New Findings Suggest The Reason Why

by Keith CowingFebruary 2, 2024

The study of “exoplanets,” the sci-fi-sounding name for all planets in the cosmos beyond our own solar system, is a pretty new field. Mainly, exoplanet researchers like those in the […]

Comparative gene expression during cloudy and clear conditions: (A) RNA-to-DNA concentration ratio for clouds and clear atmospheric conditions; dots indicate individual samples, and boxplots display medians, 25th and 75th percentiles, and whiskers 1.5 interquartile ranges; ** indicates highly significant difference, highlighting the relatively higher total RNA concentration in clouds (Mann-Whitney test, p-value=0.004); (B) Non-Metric Multidimensional Scaling (NMDS) polygons based on the 21,046 functional gene entries in MGs and MTs, illustrating the distinction between MGs and MTs, and the differences between MTs during cloudy and clear conditions; (C) volcano plot representing differential gene expression between atmospheric conditions, with genes significantly overexpressed in and outside clouds in blue and red, respectively; grey dots represent genes whose expression level is not affected; dashed lines represent significance thresholds; DEA coefficient: Differential Expression Analysis (DEA) coefficient, from the MTXmodel R package (78); this illustrates that overexpression of distinct genes depends on the atmospheric condition; (D) numbers of overrepresented Gene Ontology terms (GOs) derived from gene annotations during cloudy and clear conditions, in blue and red, respectively, referring to their classification as Biological Processes (BP), Cellular Components (CC) and Molecular Functions (MF). A number of biological functions are overexpressed in clouds compared with clear conditions. -- biorxiv.org

Atmospheres, Climate, Weather, Biophysics, Genomics, Proteomics, Bioinformatics, Microbiology & Virology, Status Report, Venus

Clouds, Oases For Airborne Microbes – Differential Metagenomics/ Metatranscriptomics Analyses Of Cloudy And Clear Atmospheric Situations

by Keith CowingJanuary 10, 2024January 10, 2024

Editor’s note: with recent speculation about the potential habitability of the clouds of Venus and the long-hypothesized notion of airborne life forms on Saturn and Jupiter these studies from Earth […]

Clouds

Terraforming / Geoengineering: Clouds Dissipate Quickly During Solar Eclipses As The Land Surface Cools

Feasibility Study on Retrieving Exoplanetary Cloud Cover Distributions Using Polarimetry

Information Content of JWST Spectra of WASP-39b

Constraints On Atmospheric Water Abundance and Cloud Deck Pressure in the Warm Neptune GJ 3470 b via CARMENES Transmission Spectroscopy

Data Availability And Requirements Relevant For The Ariel Space Mission And Other Exoplanet Atmosphere Applications

Atmospheric Waves Driving Variability and Cloud Modulation on a Planetary-Mass Object

Clouds And Seasonality On Terrestrial Planets With Varying Rotation Rates

Neptune-like Exoplanets Can Be Cloudy Or Clear — New Findings Suggest The Reason Why

Clouds, Oases For Airborne Microbes – Differential Metagenomics/ Metatranscriptomics Analyses Of Cloudy And Clear Atmospheric Situations

Opportunity to Contribute to NASA DARES Community White Paper on Phototrophic Biosignatures

NASA Establishes Mars Forward Operational Risk and Contamination Evaluation (M-FORCE) Tiger Team to Shape Mars Planetary Protection Protocols

Miraflores Butte On Mars

Ocean World Exploration: 2026 American Samoa ROV + Mapping Exploration

Development Of An Adaptive Optics Testbed At MPIA For The ELT/Planetary Camera And Spectrograph (PCS)