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All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Springtime SEA Air Is Consistently Both Smoky and Humid, but This Relationship (and Its Radiative Effects) Varies Spatially and Seasonally

The atmosphere over the southeast Atlantic Ocean (SEA) sees a consistent springtime biomass burning (BB) smoke from widespread agricultural fires on the African continent. This smoke layer is initially lofted high in a continental mixed layer (~5-6km) and is then transported westward in the free troposphere, where it overlies and ultimately mixes into the SEA stratocumulus-topped oceanic boundary layer. Coincident with this smoke is an elevated humidity signal which is present from the time a given airmass is over the continental source region. ORACLES (ObseRvations of Aerosols above CLouds and their intEractionS) was a NASA Earth Venture Suborbital mission with the goal of measuring aerosol, cloud, and atmospheric properties over this region during three deployments in September 2016, August 2017, and October 2018. A previous study discussed the spatial characteristics of the water vapor-BB plume observations in the September 2016 flight data and their degree of agreement with several atmospheric reanalyses and models. In the present work, we first discuss atmospheric chemistry, structure, and aerosol results from all three ORACLES deployments to place these results in a broader seasonal context. Despite the differing locations and season of each deployment, we show that there continues to be good agreement between the airborne ORACLES dataset and large-scale reanalyses, specifically the ECMWF ERA5 and CAMS reanalyses. Other reanalyses (specifically NASA's MERRA-2) preserved the observed correlation between meteorology and biomass burning conditions, but, as was seen for 2016, was frequently displaced spatially relative to the observations. The CAMS reanalysis performs better with water vapor than with CO. Results comparing CAMS column AOD to the field measurements show slight overestimates, consistent with previous analysis, but the good relationship observed between AOD and inlet-based aerosol extinction demonstrates this metric's utility to broader studies. The good ERA5/CAMS/ORACLES agreement allows us to next examine the multi-year seasonal patterns and trends beyond the three ORACLES deployment periods. Looking at seven years of reanalysis data for the BB season, we find distinct variations between each month/deployment in terms of vertical smoke distribution and correlation to atmospheric specific humidity, due to changing conditions through the BB season. Using k-means clustering of these climatological reanalysis, we identify six canonical atmospheric profile types of varying total atmospheric humidity and vertical structure and describe their changing incidence spatially and throughout the season, and six analogous profile types for carbon monoxide, allowing us to characterize the atmospheric structure of both vapor and BB over time throughout the SEA region. This classification will allow for a more complete analysis of the broader radiative and dynamical effects of humid aerosols overlying stratocumulus clouds.

Kristina Marie Myers Pistone↗
NASA NTRSDate not supplied

The Seasonal Evolution of Atmospheric Vertical Structure of Smoke and Humidity Over the Southeast Atlantic Biomass Burning Region

The atmosphere over the southeast Atlantic Ocean (SEA) sees a consistent springtime biomass burning (BB) smoke from widespread agricultural fires on the African continent. This smoke layer is initially lofted high in a continental mixed layer (~5-6km) and is then transported westward in the free troposphere, where it overlies and ultimately mixes into the SEA stratocumulus-topped oceanic boundary layer. Coincident with this smoke is an elevated humidity signal which is present from the time a given airmass is over the continental source region; this correlation is persistent through the biomass burning season, although varying through the course of the season. ORACLES (ObseRvations of Aerosols above CLouds and their intEractionS) was a NASA Earth Venture Suborbital mission with the goal of measuring aerosol, cloud, and atmospheric properties over this region during three deployments in September 2016, August 2017, and October 2018. We use the ORACLES observations to assess this smoke-vapor relationship. First, we discuss the good agreement between the airborne ORACLES dataset and the ECMWF ERA5 and CAMS reanalyses, as well as results from NASA’s MERRA-2, as seen over the three deployment years. We then use the reanalyses to develop a framework in which to understand more broadly the radiative and dynamical interactions between the elevated smoke and water vapor over the SEA through the biomass burning season, beyond the three ORACLES observation periods. Looking at seven years of reanalysis data for the BB season, we find distinct variations between each month/deployment in terms of vertical smoke distribution and correlation to atmospheric specific humidity, due to changing conditions through the BB season. Using k-means clustering of these climatological reanalyses, we identify six canonical atmospheric profile types of varying total atmospheric humidity and vertical structure and describe their changing incidence spatially and throughout the season, and six analogous profile types for carbon monoxide, allowing us to characterize the atmospheric structure of both vapor and BB over time throughout the SEA region. The radiative heating of both aerosol and water vapor has potential to influence the cloud-top entrainment and atmospheric turbulence, thus modifying the underlying stratocumulus cloud properties. We next discuss how these smoke-humidity variations influence both the low-cloud fraction (as observed by MODIS and VIIRS, and output by ERA5) and the boundary layer height in the region. This classification will ultimately allow for a more complete analysis of the broader radiative and dynamical effects of humid aerosols overlying stratocumulus clouds.

Kristina Marie Myers Pistone↗
NASA NTRSDate not supplied

Cloud Condensation Nuclei in the Early Martian Atmosphere

Explanations for how early Mars supported warmer and wetter conditions 3.5 to 4 billion years ago have long been debated. A water cloud greenhouse has been proposed as a mechanism of warming early Mars, but modeling studies of these environments produce mixed results. Studies show that both H 2 O and CO 2 clouds are capable of influencing atmospheric and surface temperatures, but the amount of warming induced is very sensitive to the cloud physics assumptions made. Producing a strong water cloud greenhouse effect is dependent on forming clouds as high in the atmosphere as possible to maximize warming. However, the majority of studies of H 2 O and CO 2 clouds on early Mars assume that a constant number of seed nuclei are available at all altitudes for clouds to condense onto. Here we test the validity of this assumption in massive CO 2 atmospheres. Explaining how dust is lofted into the middle atmosphere to serve as seed nuclei for cloud formation is a challenge even for present day Mars. This problem may change in an early Mars environment where having a more massive atmosphere could result in differences in the general circulation, vertical transport, and settling time scales of dust. Here, we begin a first-ever study of the early Mars dust cycle and how it might couple to the water cycle. We present early Mars simulations in which dust is injected at the surface and can be transported throughout the atmosphere. We explore the resulting vertical and horizontal distributions of dust particles and their sizes with an emphasis on the maximum height of the dust. We aim to investigate what the distribution of cloud condensation nuclei may have been on early Mars and how this might impact cloud formation.

Kathryn Steakley↗
NASA NTRSDate not supplied

Martian B Storm Evolution: Modeling Dust Activity over the Receding South Polar CO 2 Ice Cap at Southern Hemisphere Summer Solstice

Observations of annually recurring, elevated (25 km) atmospheric warming and associated dust concentrations over the south polar cap near Southern Hemisphere (SH) summer solstice are the defining features of the regional dust storm known as the B storm [1]. Our observational analysis of MCS and TES temperature and dust retrievals include all Mars Years (MY) lacking a global dust storm (GDS) between MY 26 and MY 33 (Figure 1). The data indicate the B storm is initiated around perihelion (L s =252°) in the southern midlatitudes and reaches maximum height and intensity over the south pole near SH summer solstice at L s ~267°. At peak intensity, mid-level atmospheric temperatures are elevated by as much as 30 K and mid-level atmospheric dust mixing ratios are more than triple pre-B storm levels (1.5-2 ppm to 7-8 ppm). Cap edge lifting may contribute significantly to initial dust mobilization in the B storm since surface wind stress along the receding cap edge is likely strengthened by the combined effects of the sea breeze circulation and katabatic winds at this time of year [2, 3, 4]. We are investigating dust lifting and lofting near the south pole of Mars during SH summer using the NASA Ames Mars Global Climate Model (MGCM). The NASA Ames MGCM is a finite-volume numerical model with a cubed sphere grid ideal for modeling processes at high latitudes. Initial simulations at low resolution (4x4 degrees) capture some elevated dust and associated warming at the south pole around L s =265°, but the model fails to capture the intensity of the B storm. We will examine and present the model-predicted surface stress and vertical velocities near the receding seasonal CO 2 cap edge and at the south pole during solstice. Finally, we will present higher resolution simulations to better capture small-scale dynamics and features at the pole.

Courtney M. L. Batterson↗
NASA NTRSDate not supplied

The B Regional Dust Storm in the New NASA Ames Mars GCM

Introduction The Thermal Emission Spectrometer (TES) and the Mars Climate Sounder (MCS) instruments have been ob- serving global dust and temperature on Mars twice daily for a combined ∼12 Mars Years (MYs). Analysis of these data by [5] reveal three highly repeatable, regional scale dust events occurring annually during years lack- ing a global dust storm (GDS). Named the "A," "B," and "C" storms in seasonal order, these recurring dust storms develop in the southern hemisphere of Mars during the perihelion season(Ls =180°–360°)when Mars is closest to the sun and the southern hemisphere experiences sum- mer [5]. The "A" and "C" storms occur in the southern midlatitudes where they amplify the Hadley circulation causing dynamical warming in the northern hemisphere. In contrast, the "B" storm (hereafter, B storm) and its ef- fects are entirely confined to the south pole [5]. All three storms are large enough to inject dust above the boundary layer [8]. As a result, the annually-recurring regional storms produce significant temperature perturbations in the middle atmosphere, raising zonal mean 50 Pa ( 25 km) temperatures above 200 K (Figure 1) [5]. In this work, we seek to identify the mechanisms responsible for lofting dust into the middle atmosphere during the B storm by simulating the storm with the new NASA Ames Mars Global Climate Model (MGCM). We find that the simulated B storm is driven by a series of dust plumes that form in the high southern latitudes during southern summer solstice. We also find that radiative-dynamic feedbacks between airborne dust and incoming shortwave radiation are crucial for the pluming mechanism.

C M L Batterson↗
NASA NTRS2024

Inverse Modeling of the Initial Stage of the 1991 Pinatubo Volcanic Cloud Accounting for Radiative Feedback of Volcanic Ash

The way volcanic clouds evolve is very sensitive to the initial spatial 3D distributions of volcanic materials, which are often unknown. In this study, we conducted inverse modeling of the Mt. Pinatubo cloud using TOMS 2D mapping of Aerosol Index and SO 2 loading during the first three post-eruption days to estimate the time-dependent emissions profiles and initial 3D spatial distributions of volcanic ash and SO 2 . We account for aerosol radiative feedback and dynamic lofting of volcanic ash in the inversion calculations for the first time. This resulted in a lower ash injection height (by 1.5 km for ash) than without ash radiative feedback. The Pinatubo eruption ejected ≈77% of fine ash at 12 to 23 km, ≈65% of SO 2 at 18–25 km. In contrast with previous studies, which suggested that all volcanic materials were emitted above the tropopause, a significant fraction of SO 2 (5.1 of 15.5 Mt) and fine ash (37.2 of 66.5 Mt) were ejected in the troposphere, where SO 2 quickly oxidized into sulfate aerosol that is short-lived in the troposphere. This explains the early presence of sulfate aerosols in the plume and why the models can reproduce the observed volcanic aerosols' optical depth (AOD), assuming lower-than-observed SO 2 emission in the stratosphere. Despite the quicker than in observations build-up of sulfate AOD, in a month after the eruption, the evolution of the Pinatubo AOD simulated using the obtained ash and SO 2 initial distributions converges with the available stratospheric aerosol and gas experiment (SAGE) observations.

Pinatubo volcanic ash and SO2 emissions↗
NASA NTRSDate not supplied

Convective Transport to the Upper Troposphere and Lower Stratosphere Over the Asian Summer Monsoon as Observed During the 2022 ACCLIP Airborne Campaign

Deep convection in the Asian summer monsoon (ASM) rapidly transports boundary layer pollutants including ozone-depleting substances into the upper troposphere and lower stratosphere (UTLS). The confinement of the seasonal anticyclonic circulation in the UTLS over Asia initially traps the pollutants near the tropopause level, but air masses are subsequently transported throughout the global stratosphere and impact Earth’s climate. Characterizing the transport pathways and processes of these pollutants are critical for identifying source regions and quantifying regional contributions to global stratospheric concentrations. The Asian summer monsoon Chemical and Climate Impact Project (ACCLIP) was conducted in summer 2022 using two high-altitude aircraft (NSF NCAR Gulfstream V and the NASA WB-57) to obtain UTLS chemical composition and aerosol distribution for characterizing the impact of the ASM on global chemistry and climate. Backward trajectories from ACCLIP flight tracks were traced through time-varying, satellite-derived global convective cloud top altitude fields to investigate the convective air mass origins of the sampled air parcels. Analyses reveal that air masses lofted by convection within the ASM (South Asian summer monsoon) and near the edge of the of the ASM anticyclone (East Asian summer monsoon) contributed to the airborne observations. In this study, we present a summary of the transport statistics of UTLS air masses sampled during ACCLIP and discuss the implications of these results on our understanding of the role of ASM in global constituent transport.

Convective↗
NASA NTRS2026

Ice in Convective Storm Environments: Assessing Impacts of Microphysics on Simulated Reflectivities

Satellite radar retrievals of clouds and precipitation rely on assumptions about the microphysical properties of hydrometeors such as particle size distributions (PSDs) and massdimensional relationships, which have been shown to vary in distinct environments. A deeper understanding of linkages between mass-dimensional relationships, ice crystal shape, and radar reflectivities across cloud and precipitation regimes is necessary for developing new retrievals for upcoming satellite radar missions, including the INvestigation of Convective UpdraftS (INCUS), as well as future missions that will feature space-borne radars observing clouds, convection, and precipitation. This study investigates ice microphysical characteristics through aircraft in-situ and remote sensing observations from two convective events during the Mid-latitude Continental Convective Clouds Experiment (MC3E) in the Southern Great Plains, and tests implications for ice particle habit in forward modeled radar observations. During MC3E, the Ka/Ku- band High Altitude Imaging Wind and Rain Airborne Profiler (HIWRAP) was onboard the NASA ER-2 aircraft, while in-situ measurements were taken onboard the University of North Dakota Citation. In-situ PSDs and particle shape information from optical array probe data are used to forward model radar reflectivities from particle scattering databases and are compared against HIWRAP reflectivities. Various particle combinations can be used to find agreement with HIWRAP observations, and the forward modeled reflectivities were sensitive to particle type. Varying the riming on the aggregate and graupel particles resulted in larger than 10 dB differences in reflectivities. The in-situ and radar observations imply the occurrence of aggregation, size sorting and lofting particles.

Julia A. Shates↗
DOE OSTI2020

System and method for thermally adaptive materials

An adaptive sheet that includes a first layer defining a first length, the first layer configured to assume a base configuration in response to a first environmental condition and assume a lofted configuration in response to a second environmental condition with the first layer being curled along the first length compared the base configuration. The first fabric layer includes a first material defining a second length and having a first expansion coefficient, and wherein the first material is configured to increasingly change length along the second length in response to the second environmental condition, and a second material defining a third length and having a second expansion coefficient that is different than the first expansion coefficient.

36 MATERIALS SCIENCE↗
NASA NTRS2012

X-Hab Challenge: Students in the Critical Path

The eXploration Habitat (X-Hab) Academic Innovation Challenge follows a non-typical format for university student competitions. Rather than provide a realistic simulated mission for the students to perform, the X-Hab Challenge puts the student teams in the critical path of NASA's human space flight Exploration systems research and development, and expects them to deliver a product that will likely become heritage for eventual flight systems in the years to come. The added responsibility has two major benefits: the university teams are given real ownership in the NASA vision; students are given Principal Investigator (PI) status for their contribution and are looked upon as peers in the development process. This paper introduces the X-Hab Challenge and discusses the successes behind the program.

X-Loft↗
NASA NTRS2020

Perspectives on Data Reproducibility and Replicability in Paleoclimate and Climate Science

This paper summarizes the current state of reproducibility and replicability in the fields of climate and paleoclimate science, including brief histories of their development and applications in climate science, new and recent approaches towards improvement of reproducibility and replicability, and challenges. Recommendations for addressing those challenges include: development of searchable, auto-updated, interlinked, multi-archive public paleoclimate repositories for raw and processed digital datasets; cross-center standardized code base cases, improved data storage techniques, and a focus on replicability for climate simulation storage and access; and support of the development and community awareness of findable, accessible, interoperable and reusable (FAIR) principles by funding agencies and publishers. This paper is largely based on the May 2018 presentations of a panel of researchers to the Committee on Reproducibility and Replicability in Science, part of the National Academies of Science, Engineering, and Medicine. The commentary and recommendations made here are in alignment with those of its Consensus Study Report on Reproducibility and Replicability in Science (2019).

data repositories↗