Airborne lidar observations of wind, water vapor, and aerosol profiles during the NASA Aeolus calibration and validation (Cal/Val) test flight campaign

Lidars are uniquely capable of collecting high-precision and high spatiotemporal resolution observations that have been used for atmospheric process studies from the ground, aircraft, and space for many years. The Aeolus mission, the first space-borne Doppler wind lidar, was developed by the European Space Agency (ESA) and launched in August 2018. Its novel Atmospheric LAser Doppler INstrument (ALADIN) observes profiles of the component of the wind vector and aerosol/cloud optical properties along the instrument's line-of-sight (LOS) direction on a global scale. A total of two airborne lidar systems have been developed at NASA Langley Research Center in recent years that collect measurements in support of several NASA Earth Science Division focus areas. The coherent Doppler Aerosol WiNd (DAWN) lidar measures vertical profiles of LOS velocity along selected azimuth angles that are combined to derive profiles of horizontal wind speed and direction. The High Altitude Lidar Observatory (HALO) measures high resolution profiles of atmospheric water vapor (WV) and aerosol and cloud optical properties. Because there are limitations in terms of spatial and vertical detail and measurement precision that can be accomplished from space, airborne remote sensing observations like those from DAWN and HALO are required to fill these observational gaps and to calibrate and validate space-borne measurements. Over a 2-week period in April 2019, during their Aeolus Cal/Val Test Flight campaign, NASA conducted five research flights over the eastern Pacific Ocean with the DC-8 aircraft. The purpose was to demonstrate the following: (1) DAWN and HALO measurement capabilities across a range of atmospheric conditions, (2) Aeolus Cal/Val flight strategies and comparisons of DAWN and HALO measurements with Aeolus, to gain an initial perspective of Aeolus performance, and (3) ways in which atmospheric dynamic processes can be resolved and better understood through simultaneous observations of wind, WV, and aerosol profile observations, coupled with numerical model and other remote sensing observations. This paper provides a brief description of the DAWN and HALO instruments, discusses the synergistic observations collected across a wide range of atmospheric conditions sampled during the DC-8 flights, and gives a brief summary of the validation of DAWN, HALO, and Aeolus observations and comparisons.</p

Atmospheric Carbon and Transport - America (ACT-America) Data Sets: Description, Management, and Delivery

Abstract The ACT‐America project is a NASA Earth Venture Suborbital‐2 mission designed to study the transport and fluxes of greenhouse gases. The open and freely available ACT‐America data sets provide airborne in situ measurements of atmospheric carbon dioxide, methane, trace gases, aerosols, clouds, and meteorological properties, airborne remote sensing measurements of aerosol backscatter, atmospheric boundary layer height and columnar content of atmospheric carbon dioxide, tower‐based measurements, and modeled atmospheric mole fractions and regional carbon fluxes of greenhouse gases over the Central and Eastern United States. We conducted 121 research flights during five campaigns in four seasons during 2016–2019 over three regions of the US (Mid‐Atlantic, Midwest and South) using two NASA research aircraft (B‐200 and C‐130). We performed three flight patterns (fair weather, frontal crossings, and OCO‐2 underflights) and collected more than 1,140 h of airborne measurements via level‐leg flights in the atmospheric boundary layer, lower, and upper free troposphere and vertical profiles spanning these altitudes. We also merged various airborne in situ measurements onto a common standard sampling interval, which brings coherence to the data, creates geolocated data products, and makes it much easier for the users to perform holistic analysis of the ACT‐America data products. Here, we report on detailed information of data sets collected, the workflow for data sets including storage and processing of the quality controlled and quality assured harmonized observations, and their archival and formatting for users. Finally, we provide some important information on the dissemination of data products including metadata and highlights of applications of ACT‐America data sets

Glycoengineering HIV-1 Env creates ‘supercharged’ and ‘hybrid’ glycans to increase neutralizing antibody potency, breadth and saturation

<div><p>The extensive glycosylation of HIV-1 envelope (Env) glycoprotein leaves few glycan-free holes large enough to admit broadly neutralizing antibodies (bnAb). Consequently, most bnAbs must inevitably make <i>some</i> glycan contacts and avoid clashes with others. To investigate how Env glycan maturation regulates HIV sensitivity to bnAbs, we modified HIV-1 pseudovirus (PV) using various glycoengineering (GE) tools. Promoting the maturation of α-2,6 sialic acid (SA) glycan termini increased PV sensitivity to two bnAbs that target the V2 apex and one to the interface between Env surface gp120 and transmembrane gp41 subunits, typically by up to 30-fold. These effects were reversible by incubating PV with neuraminidase. The same bnAbs were unusually potent against PBMC-produced HIV-1, suggesting similar α-2,6 hypersialylated glycan termini may occur naturally. Overexpressing β-galactosyltransferase during PV production replaced complex glycans with hybrid glycans, effectively 'thinning' trimer glycan coverage. This increased PV sensitivity to some bnAbs but ablated sensitivity to one bnAb that depends on complex glycans. Other bnAbs preferred small glycans or galactose termini. For some bnAbs, the effects of GE were strain-specific, suggesting that GE had context-dependent effects on glycan clashes. GE was also able to increase the percent maximum neutralization (i.e. saturation) by some bnAbs. Indeed, some bnAb-resistant strains became highly sensitive with GE—thus uncovering previously unknown bnAb breadth. As might be expected, the activities of bnAbs that recognize glycan-deficient or invariant oligomannose epitopes were largely unaffected by GE. Non-neutralizing antibodies were also unaffected by GE, suggesting that trimers remain compact. Unlike mature bnAbs, germline-reverted bnAbs avoided or were indifferent to glycans, suggesting that glycan contacts are acquired as bnAbs mature. Together, our results suggest that glycovariation can greatly impact neutralization and that knowledge of the optimal Env glycoforms recognized by bnAbs may assist rational vaccine design.</p></div

Comparison of the effects of B4GALT1+ST6GAL1 and PBMC passage on PV and IMC sensitivities.

<p>Viruses from 5 HIV-1 strains were produced as PVs or infectious molecular clones (IMCs). Some 293T cell-derived PVs were modified by B4GALT1+ST6GAL1, as indicated. Some IMCs were passaged through PBMCs as indicated. Neutralization assays were performed with the addition of indinavir to assays using IMCs to limit infection to a single round. Results are representative of at least two repeats performed in duplicate.</p

Atmospheric carbon and transport – America (ACT-America) data sets: description, management, and delivery

The ACT-America project is a NASA Earth Venture Suborbital-2 mission designed to study the transport and fluxes of greenhouse gases. The open and freely available ACT-America data sets provide airborne in situ measurements of atmospheric carbon dioxide, methane, trace gases, aerosols, clouds, and meteorological properties, airborne remote sensing measurements of aerosol backscatter, atmospheric boundary layer height and columnar content of atmospheric carbon dioxide, tower-based measurements, and modeled atmospheric mole fractions and regional carbon fluxes of greenhouse gases over the Central and Eastern United States. We conducted 121 research flights during five campaigns in four seasons during 2016–2019 over three regions of the US (Mid-Atlantic, Midwest and South) using two NASA research aircraft (B-200 and C-130). We performed three flight patterns (fair weather, frontal crossings, and OCO-2 underflights) and collected more than 1,140 h of airborne measurements via level-leg flights in the atmospheric boundary layer, lower, and upper free troposphere and vertical profiles spanning these altitudes. We also merged various airborne in situ measurements onto a common standard sampling interval, which brings coherence to the data, creates geolocated data products, and makes it much easier for the users to perform holistic analysis of the ACT-America data products. Here, we report on detailed information of data sets collected, the workflow for data sets including storage and processing of the quality controlled and quality assured harmonized observations, and their archival and formatting for users. Finally, we provide some important information on the dissemination of data products including metadata and highlights of applications of ACT-America data sets

Glycan contacts of mature bnAbs are not germline-encoded.

<p>A) GE PVs from donor CAP256 [<a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1007024#ppat.1007024.ref035" target="_blank">35</a>] at week 34 were tested for neutralization sensitivity to bnAbs CAP256.09, CAP256.25, intermediate I1 and the inferred unmutated common ancestor (UCA). B) GE-modified 16055 and Q23.17 PVs were tested for sensitivity to PG9 with a reverted heavy chain (gH) mixed with the mature light chain (mL) and fully mature PG9. Results are representative of two replicates; error bars represent SD. C) Nine V2-sensitive strains [<a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1007024#ppat.1007024.ref034" target="_blank">34</a>, <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1007024#ppat.1007024.ref036" target="_blank">36</a>, <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1007024#ppat.1007024.ref045" target="_blank">45</a>] produced in control, B4GALT1+ST6GAL1 and GNT1- formats were tested for sensitivity to V2 bnAbs and their germline revertants, as indicated. The CH04 UCA (RUA/RUA) was the same as that used in ref [<a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1007024#ppat.1007024.ref033" target="_blank">33</a>]. Mixed mHgL versions of PGT145 and VRC38.01 were used that previously showed the most reactivity of the ancestors tested [<a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1007024#ppat.1007024.ref034" target="_blank">34</a>, <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1007024#ppat.1007024.ref042" target="_blank">42</a>]. Results are representative of at least two repeats performed in duplicate. Wilcoxon Signed Rank tests were performed on data for each mAb-PV pair, organized into two columns to compare IC50s for control and GE-modified formats. Significant p values are shown.</p

Effects of GE on bnAb neutralization IC50s.

<p>Neutralizing IC50s for each control and GE-modified A) JR-FL and B) BG505 PVs are shown in μg/ml. The most sensitive glycoform for each nAb is boxed. JR-FL neutralization assays for mAb 3BC176 used the N88A mutant. Each assay was performed at least in duplicate. In many cases, BG505 neutralization by mAb 35O22 was insufficiently saturating to reach an IC50 and is denoted by a "+". Geometric mean IC50s per treatment are shown, omitting data for 14e, F105 and instances of 35O22 "+". This Fig is linked to <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1007024#ppat.1007024.g003" target="_blank">Fig 3</a>, <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1007024#ppat.1007024.s002" target="_blank">S2</a> and <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1007024#ppat.1007024.s006" target="_blank">S6</a> Figs. Abbreviations: B4G = B4GALT1, ST3 = ST3GAL4, ST6 = ST6GAL1, ST8 = ST8SIA4.</p

BN-PAGE-Western blot analysis of the effects of GE on particulate Env.

<p>Equal volumes (500x concentration) of GE-modified JR-FL SOS E168K gp160ΔCT VLPs (produced using MuLV Gag and Rev) and human PBMC-propagated replicating JR-FL virus were lysed and analyzed by BN PAGE-Western blot. Env was detected using an anti-HIV primary cocktail (39F, 4E10 and 2F5). Trimer and monomer bands are indicated by cartoons along with ferritin markers. Lanes 20 and 21 are enhanced versions of lanes 18 and 19 to better visualize PBMC Env (lane 21). Abbreviations: B4G = B4GALT1, ST6 = ST6GAL1, ST3 = ST3GAL4, ST8 = ST8SIA4.</p