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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Investigation on cloud vertical structures based on Ka-band cloud radar observations at Wuhan in Central China

Based on vertically pointing observations of Ka-band frequency-modulated continuous millimeter wave cloud radar (MMCR) in 2020, we investigate cloud vertical structures at Wuhan in central China. Case comparison indicates that the cloud top locations in the MMCR observation are largely consistent with those in satellite data. The precipitation has the occurrence frequency of 9.5% over the year, with the maximum value of 16.3% in July and the submaximal value of 14.7% in January, showing the significant influences of monsoons on precipitation at Wuhan. As the humid, cloudy and rainy climate, the probability of precipitation and non-precipitation clouds increases gradually from 53.9% in January to a large value of 71.5% in July. The non-precipitation clouds have the probability of 44.5% in the year, with two prominent peaks at the reflectivities of -35 to -30 dBZ around 12 km in summer and - 37– -32 dBZ around 10 km in spring. The cloud top can reach the heights of 14.49, 16.62, 13.38 and 11.73 km from spring to winter, respectively. The monthly mean cloud layer thickness is the largest (2.18 km) in May and September, and the smallest (1.36 km) in November. The seasonally averaged base and top heights and thickness of clouds have small diurnal variations. The high cloud is predominant in the warm months from May to September, and in the other cool months, the middle cloud has the most fraction. The quantitative investigation of clouds is helpful in improving the cloud parameterization in climate models.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

A global gridded dataset for cloud vertical structure from combined CloudSat and CALIPSO observations

Abstract. The vertical structure of clouds has a profound effect on the global energy budget, the global circulation, and the atmospheric hydrological cycle. The CloudSat and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) missions have taken complementary, colocated observations of cloud vertical structure for over a decade. However, no globally gridded dataset is available to the public for the full length of this unique combined data record. Here we present the 3S-GEOPROF-COMB product (Bertrand et al. 2023, https://doi.org/10.5281/zenodo.8057791), a globally gridded (level 3S) community data product summarizing geometrical profiles (GEOPROF) of hydrometeor occurrence from combined (COMB) CloudSat and CALIPSO data. Our product is calculated from the latest release (R05) of per-orbit (level-2) combined cloud mask profiles. We process a set of cloud cover, vertical cloud fraction, and sampling variables at 2.5, 5, and 10° spatial resolutions and monthly and seasonal temporal resolutions. We address the 2011 reduction in CloudSat data collection with Daylight-Only Operations (DO-Op) mode by subsampling pre-2011 data to mimic DO-Op collection patterns, thereby allowing users to evaluate the impact of the reduced sampling on their analyses. We evaluate our data product against CloudSat-only and CALIPSO-only global-gridded data products as well as four comparable surface-based sites, underscoring the added value of the combined product. Interest in the product is anticipated for the study of cloud processes, cloud–climate interactions, and as a candidate baseline climate data record for comparison to follow-up satellite missions, among other uses.

Bertrand, Leah (ORCID:0009000001607558)↗
NASA NTRS2020

An Evaluation of Clouds and Radiation in a Large-Scale Atmospheric Model Using a Cloud Vertical Structure Classification

We revisit the concept of the cloud vertical structure (CVS) classes we have previously employed to classify the planet's cloudiness (Oreopoulos et al., 2017). The CVS classification reflects simple combinations of simultaneous cloud occurrence in the three standard layers traditionally used to separate low, middle, and high clouds and was applied to a dataset derived from active lidar and cloud radar observations. This classification is now introduced in an atmospheric global climate model, specifically a version of NASA's GEOS-5, in order to evaluate the realism of its cloudiness and of the radiative effects associated with the various CVS classes. Such classes can be defined in GEOS-5 thanks to a sub column cloud generator paired with the model's radiative transfer algorithm, and their associated radiative effects can be evaluated against observations. We find that the model produces 50% more clear skies than observations in relative terms and produces isolated high clouds that are slightly less frequent than in observations, but optically thicker, yielding excessive planetary and surface cooling. Low clouds are also brighter than in observations, but underestimates of the frequency of occurrence (by ~20% in relative terms) help restore radiative agreement with observations. Overall the model better reproduces the longwave radiative effects of the various CVS classes because cloud vertical location is substantially constrained in the CVS framework.

Lee, Dongmin↗
NASA NTRS1990

Precipitating cloud vertical structure derived from passive microwave radiometry

A procedure for the retrieval of cloud vertical structure from passive microwave radiometry is demonstrated by using passive microwave radiometry observations made during the Tropical Rainfall Measuring Mission. The procedure uses a set of cloud radiative models, with each model consisting of five vertical layers, specifying a distinct cloud vertical structure in terms of the near-surface parameters. The retrieval procedure is separated into two tasks (1) retrieving a set of geophysical parameters for each cloud radiative model and (2) finding which of the cloud radiative models and its associated retrieved parameters best fit the observed geophysical conditions. It is shown that this retrieval technique can detect differences and similarities between precipitating systems.

Kummerow, Christian D.↗
NASA NTRS2024

Regimes of Cloud Vertical Structure From Active Observations

We introduce a new type of cloud class, which we call “active cloud regime” (ACR), owing to its provenance from active (lidar and cloud radar) spaceborne cloud observations. ACRs intend to provide a climatological description based on cloud vertical structure (CVS) of the most prevalent monthly CVS mixtures encountered at large spatial scales of ~400 km. ACRs are thus a way to create a gridded dataset of a vertically-resolved cloud mask that can facilitate joint analysis with other gridded datasets. The detailed 2D cloud mask comes from the 2B-CLDCLASS-LIDAR CloudSat dataset fusing CALIPSO (lidar) and CloudSat (cloud radar) cloud detections. We show that the global classification of cloudiness under the ACR framework provides valuable insights on how the world’s dominant cloud systems regulate the two major components of atmospheric energetics, precipitation and radiative cooling. NASA’s GEOS model allows us to demonstrate the feasibility of applying the ACR concept in Earth System Models that have the capability to produce subgrid cloudiness obeying pre-specified vertical overlap rules. Comparison of observed and simulated ACRs provides thus another means to assess the realism of modeled clouds.

cloud vertical structure↗
NASA NTRS1985

Vertical cloud structure of Jupiter's equatorial plumes

Multiple-scattering radiative transfer calculations were used to deduce the vertical cloud structure (VCS) of Jupiter's equatorial region. The VCS model of the equatorial plumes is obtained through an analysis of Voyager images of the 6190-A methane band and the 6000-A continuum, and ground-based 8900-A methane band images. The VCS of the equatorial plumes is found to be consistent with the hypothesis that the plumes are caused by upwelling at the ammonia condensation level produced by buoyancy due to latent heat release from the condensation of water clouds nearly three scale heights below the plumes.

Stoker, C. R.↗
NASA NTRS1995

Radar For Measuring Vertical Cloud Structure

Proposed radar system views clouds from above and measures their vertical structures with resolution of 500 m. Two versions of system; initial developmental version to be flown aboard aircraft and final version flown aboard spacecraft in circular orbit around Earth at altitude of 400 km.

Im, Eastwood↗
DOE OSTI2020

Cloud Atlas: Unraveling the Vertical Cloud Structure with the Time-series Spectrophotometry of an Unusually Red Brown Dwarf

Rotational modulations of emission spectra in brown dwarf and exoplanet atmospheres show that clouds are often distributed non-uniformly in these ultracool atmospheres. The spatial heterogeneity in cloud distribution demonstrates the impact of atmospheric dynamics on cloud formation and evolution. In this study, we update the Hubble Space Telescope (HST) time-series data analysis of the previously reported rotational modulations of WISEP J004701+680352—an unusually red late-L brown dwarf with a spectrum similar to that of the directly imaged planet HR 8799e. We construct a self-consistent spatially heterogeneous cloud model to explain the HST and the Spitzer time-series observations, as well as the time-averaged spectra of WISE 0047. Additionally, in the heterogeneous cloud model, a cloud thickness variation of around one pressure scale height explains the wavelength dependence in the HST near-IR spectral variability. By including disequilibrium CO/CH 4 chemistry, our models also reproduce the redder $J-{K}_{{\rm{s}}}$ color of WISE 0047 compared to that of field brown dwarfs. We discuss the impact of vertical cloud structure on atmospheric profile and estimate the minimum eddy diffusivity coefficient for other objects with redder colors. Our data analysis and forward modeling results demonstrate that time-series spectrophotometry with a broad wavelength coverage is a powerful tool for constraining heterogeneous atmospheric structure.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1986

Vertical cloud structure models for the NTRZ EQZ, SEB and STRZ of Jupiter

Latitude-dependent models of the vertically inhomogeneous Jovian cloud structure are presented. The models assume an atmospheric composition with (CH4)/(H2) = 2.0 x .003, (He)/(H2) = 0.11 and (NH3)/(H2) = 2.0 x .0004 consistent with the Voyager IRIS measurements and employ refractive indices appropriate for ammonia ice particles and a photochemical stratospheric aerosol layer. The free parameters of the models are determined by fitting the results of multiple, scratching calculations to the near-infrared center and limb spectra of Clark and McCord and the center-to-limb 6190, 6350, 7250, 7500, 8900 and 9500 A photometric measurements of West. The resulting synthetic center-to-limb profiles are in excellent agreement with the observations. Of the regions studied the tropical zones are the most similar, with the observed differences explained by variations in the vertical extent of the cloudy layers. The Equatorial Zone is a unique region with denser NH3 clouds than either of the tropical zones. At visible and near-infrared wavelengths the belt-zone contrasts can be explained by opacity differences. The optical depth of the stratospheric aerosol layer is larger in a belt, while the tropospheric clouds are deeper and thinner.

Carlson, B. E.↗
DOE OSTI2026

High-Resolution LiDAR Observations for Coupled Effects of Dry-Air Entrainment and Haze-Cloud Interactions on Cloud Vertical Structure

This study demonstrates the high-resolution profiling of cloud microphysics in a laboratory chamber using Time-Correlated Single Photon Counting (TCSPC) LiDAR. We present a novel retrieval method to derive vertical extinction (𝜎) profiles, constrained by in situ measurements, to diagnose responses to dry-air entrainment. In clean clouds, the LiDAR signals and retrieved 𝜎 remain relatively uniform, with entrainment effects confined to the upper layer. In contrast, polluted clouds exhibit strong vertical variability and a transition to a water-vapor-limited state. Entrainment significantly enhances the haze number concentration (𝑁ℎ), particularly near the bottom, creating highly height-dependent extinction profiles for polluted clouds. Our results highlight the capability of high-resolution LiDAR in capturing fine-scale vertical inhomogeneities. This approach provides a robust framework for quantifying how aerosol loading modulates entrainment sensitivity, offering new insights into the transition between buffered and water-vapor-limited regimes.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2023

Insights into the relation between vertical cloud structure and dynamics of three polar lows: Observations from COMBLE

The vertical structure of three polar lows is described using profiling radar, lidar, and passive remote sensors deployed at a coastal site in northern Norway. The data were collected as part of the Cold-air Outbreaks in the Marine Boundary Layer Experiment (COMBLE). These data are examined in the context of satellite imagery, operational weather radar reflectivity imagery, and output from the AROME-Arctic model. A comparison to satellite images shows that AROME-Arctic captured the polar lows well. All three polar lows form in marine cold-air outbreaks and are surrounded by open-cellular convection typical of such outbreaks. Two of the lows form in a forward shear environment, and one under reverse shear. Initially, the three polar lows are comma-shaped; two of them transition to be more spirali-form at their mature stage and have mostly cloud-free warm cores. The warm cores are the result of a warm-seclusion process. All three lows have stratiform precipitation bands, marked by little cloud liquid water, and rather high surface precipitation rate. The vertical drafts and turbulence in these stratiform clouds are generally weak. In conclusion, all three lows also have convective clouds, which have stronger vertical drafts, stronger turbulence, and pockets of high liquid water content.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1980

Spatially resolved methane band photometry of Jupiter. III - Cloud vertical structures for several axisymmetric bands and the Great Red Spot

The paper presents cloud structure models for Jupiter's Great Red Spot, Equatorial and North Tropical Zones, North and South Temperate Zones, and North and South Polar Regions. The models are based on images of Jupiter in three methane bands and nearby continuum; radiative transfer calculations include multiple scattering and absorption from three aerosol layers. The model results include the transition in the upper-cloud altitude to 3 km lower altitude from the tropical zones to temperate zones and polar regions, a N/S asymmetry in cloud thickness in the tropical and temperature zones, and the presence of aerosols up to about 0.3 bar in the Great Red Spot and Equatorial Zone. It is concluded that polarization data are sensitive to aerosols in and above the upper cloud layer but insensitive to deeper cloud structure.

West, R. A.↗
NASA NTRS1977

The vertical cloud structure of Jupiter from 5 micron measurements

From 5-micron high-spatial-resolution images of Jupiter, flux-frequency histograms of the equatorial region show a trimodal distribution of brightness temperatures. Combined with limb-darkening measurements, a three-layer cloud model for Jupiter is developed. The highest, coldest clouds, apparently homogeneous and displaying relatively little limb darkening, cover the zones. These clouds are not present over the belts, allowing observational access to deeper regions. The belts appear heterogeneous: small, localized hot areas show enhanced limb darkening, while much of the belt is distinctly cooler and exhibits shallower limb darkening. These belt properties can be explained by a cool emitting layer superposed upon a hot, dense cloud deck.

Terrile, R. J.↗
NASA NTRS1988

Determining microwave brightness temperatures from precipitating horizontally finite and vertically structured clouds

Microwave radiances that may be measured from satellite-borne radiometers operating at 37 GHz have been computed as a function of rainfall rates from horizontally finite precipitating clouds that contain both ice and liquid hydrometeors. It is found that precipitating ice at the top of the cloud depresses brightness temperatures significantly. Detailed comparison between finite clouds and the equivalent sections of plane-parallel clouds are made. Footprint averaged brightness temperatures from finite clouds are found to deviate considerably from the sectioned plane-parallel approximation, especially for large rain rates. Better agreement is achieved if a plane-parallel source function is used in the finite cloud model. The effect of shape and orientation of the precipitating cells with respect to the satellite has also been considered. It is found that the largest errors introduced by plane-parallel theory besides the footprint-filling errors are encountered when precipitating cells have large fractions of their surface below the freezing level or contain large amounts of ice.

Kummerow, C.↗