This study presents time variability of metastable orthohelium, He(23S), in polar region associated with a geomagnetic storm for the first time. Continuous 17-nights dataset of He(23S) airglow brightness at 1083 nm was obtained from a short-wavelength infrared imaging spectrograph (NIRAS-2) at the KHO, Svalbard (78.1°N, 16.0°E). The observed He(23S) airglow brightness clearly displayed responses to the geomagnetic storm in different time scales. The He(23S) airglow brightness has began to decrease sharply within an hour of sudden commencement of the storm, and it was gradually decreased over the next few days and then recovered slowly. It agreed to helium density variations at 500-km altitude calculated by MSIS. The depletion of He(23S) was mainly caused by enhanced Penning ionization due to upwelling N2 from the lower atmosphere; this was consistent with decreased O/N2 ratio in MSIS and TIMED/GUVI measurements, and electron density depletion in F region observed by EISCAT Svalbard Radar (ESR). Additionally, sudden increases in He(23S) airglow brightness were clearly found associated with intermittent electron precipitations observed by the ESR. Therefore, direct impact by precipitating electron injected from the space to the polar upper atmosphere can play significant roles in production of He(23S). The NIRAS-2 measurements have successfully demonstrated that column density of He(23S) from the upper thermosphere to the exosphere was drastically changed by forcing both from the lower atmosphere and from the space. He(23S) measurements will definitely improve our understanding of thermosphere-ionosphere coupling system and extend the coverage of space weather forecasting up to the exobase.

A document by Frederic Allegrini. Click on the document to view its contents.

Shaifullah1 and Indra Sekhar Sen11Department of Earth Sciences, Indian Institute of Technology Kanpur, UP 208016, India

A document by Qusai Al Shidi. Click on the document to view its contents.

As well as strong upward propagation of planetary waves from the troposphere, the state of the stratospheric mean flow has been recognized as a key factor for the occurrence of stratospheric sudden warmings (SSWs). The modification of the mean flow to a suitable state for an SSW occurrence is called “vortex preconditioning”. Recently, increasing attention has been paid to the role of gravity waves (GWs) in the preconditioning mechanism. However, because of the limited availability of datasets covering the whole neutral atmosphere, much uncertainty still exists in the role of GWs in the preconditioning. The aim of this study is to investigate the mechanism of modification of the mean flow in the stratosphere and mesosphere before SSWs from a climatological viewpoint and elucidate the role of GWs in it. We use two state-of-the-art datasets covering the whole neutral atmosphere: a 17-year medium-resolution reanalysis dataset and the output data from hindcast simulations performed with a GW-permitting general circulation model. It is shown that the second principal component of the zonal-mean zonal wind in the stratosphere and mesosphere tends to show a maximum prior to an SSW, characterizing preconditioning. GW forcing alters the structure of the upper part of the jet and contributes to the preconditioning along with planetary waves. Comparison of GW forcing between the reanalysis and GW-permitting model suggests that the magnitude of parameterized GW forcing is approximately half that of the GW forcing in the polar upper stratosphere where the forcing is responsible for the preconditioning.

The Terminal Tracking Camera (TTCam) imaging system on the NASA Lucy Discovery mission consists of a pair of cameras that will be used mainly as a navigation and target acquisition system for the mission’s asteroid encounters. However, a secondary science-focused function of the TTCam system is to provide wide-angle broadband images over a large range of phase angles around close approach during each asteroid flyby. The scientific data acquired by TTCam can be used for shape modeling and topographic and geologic analyses. This paper describes the pre-flight and initial in-flight calibration and characterization of the TTCams, including the development of a radiometric calibration pipeline to convert raw TTCam images into radiance and radiance factor (I/F) images, along with their uncertainties. Details are also provided here on the specific calibration algorithms, the origin and archived location of the required ancillary calibration files, and the archived sources of the raw calibration and flight data used in this analysis.

Ocean waves interact with the solid Earth, generating two dominant signals called microseisms, which carry information about energy exchange between different Earth systems. Here, we show that 6C (three-component translation and three-component rotation) observations are able to resolve their seasonal azimuthal variations. We employ the rotational motions retrieved by a small seismic array at the Pinon Flat Observatory (PFO) to investigate the two dominant microseismic sources: primary (10-20s) and secondary (3-10s) microseisms. The primary microseismic Rayleigh waves show strong seasonal variations as expected, whereas the secondary microseismic Rayleigh waves show slight seasonal changes. In contrast, we find that secondary microseismic Love waves exhibit considerable seasonality. This discrepancy from the secondary microseismic Rayleigh waves provides us with new insights into the generation mechanism of Love waves. In addition, the results suggest that rotational motions of primary microseisms retrieved by the seismic array are more sensitive to atmospheric pressure-induced ground deformation.

\sout\sout The sedimentary successions of several basins of Europe show evidence of widespread Late Jurassic aridification that is considered a long-standing conundrum in paleoclimate modeling. The distinctive feature of this event is that it appears concentrated in a discrete time interval between the Kimmeridgian (Late Jurassic) and the Berriasian (Early Cretaceous), and that it extended to eastern and southern-central Asia for a total of ~10Mkm2 in roughly the same time interval. Climate modeling has not provided a convincing explanation for this event. We compiled and reviewed paleomagnetic data from several continents including Adria, the African promontory, showing that this large-scale aridification was produced by an abrupt and transient southward migration of Eurasia towards arid tropical latitudes, while its demise coincided with a ‘retromotion’ to more humid northern latitudes in the Early Cretaceous. This movement is part of a global plate motion event, most likely due to True Polar Wander, that profoundly affected the depositional environments, the ecosystems, and the architecture of sedimentary basins worldwide.

A document by Dong Chen. Click on the document to view its contents.

The threat to human health posed by Volatile Organic Compounds-carcinogenic substances for which the EPA has set no safe threshold exposure levels-is profound 1. Despite international 2 , national and state air quality standards, and greatly improved air quality monitoring, exposure remains a health hazard. Open panel adsorption, an open-source technical solution to mitigate ambient VOCs, uses small screened panels of commodity granulated activated carbon placed in locations polluted with VOC aerosols. After pollutants are adsorbed, the panels are desorbed by pyrolysis or thermal oxidation and contaminants incinerated, and the material is reactivated. Alternative methods such as electrochemical treatment or microwave desorption are under development. A simple adsorption system for ambient air is faced with atmospheric humidity, the erratic mixing ratio of ambient air, and diffusion in the low partial pressure of pollutants in ambient air. Adsorption systems use closed reactor beds and a closely controlled and specified cubic feet per minute inlet to hasten mass transfer to breakthrough (saturation and dynamic equilibrium). OPA relies on 1) repeated flows to the adsorbent material, achieving saturation over a much longer duration; 2) deployment locations carefully chosen in order to maximize persistent and episodic acute air pollutant concentrations; and 3) increasing the adsorbent surface area by designing panels open to the air. Adsorption panels should be placed in locations where pollutants are dense, preferably where air flow is laminar with low friction (because of impermeable adjacent vertical walls, for instance) to facilitate adsorption. This design thus alternately utilizes the relatively passive diffusion of batch adsorption systems, and effusion under pressure used by the more prevalent tubular or plug flow or column reactor adsorption system. Timed jar tests utilize AC sorbent material in VOC-saturated air, with a handheld Ion Science Cub Photo-Ionization Detector unit placed into a 2.3 cubic Liter Rubbermaid Brilliance container. These tests have indicated favorable adsorption with repeated introductions of TVOC (nail polish remover), as well as rapid adsorbance under varying light, RH, and air turbulence conditions. Another initial experiment used screened panels of 4x8 mesh coconut-shell AC, adjacent to a six-lane arterial urban route. Tested by TD-GC-MS analysis using a modified EPA Method TO-17 protocol, the panels evidenced significant hydrocarbon species. Crucially, the AC was not blinded by PM 2.5, nor did competition from adsorbed H20 hinder adsorption of VOCs. Panels attached to buildings and hardscape, regularly desorbed, could offer public health co-benefits in an environmental justice context.

The increasing incidence and severity of biomass burning (BB) events pose a multidimensional threat impacting economic resilience, national security, and public health. Consequently, growing attention has been devoted to the radiative and chemical effects of BB gas and aerosol emission into the atmosphere, as well as the accompanying effects on human health. The emphasis of the work reported here concerns the efficacy of airborne spectral imaging in the longwave-infrared (LWIR) regime for visualizing and tracking trace gas content of the outflow from BB events, explicitly addressing the need for spatially resolved measurements.

Thermal structures at the sea surface are known to affect the overlying atmospheric dynamics over various spatio-temporal scales, from hourly and sub-kilometric to annual and O(1000 km). The relevant mechanisms at play are generally identified by means of correlation coefficients (in space or time) or by linear regression analysis using appropriate couples of variables. For fine spatial scales, where SST gradients get stronger, the advection might disrupt these correlations and, thus, mask the action of such mechanisms, just because of the chosen metrics. For example, at the oceanic sub-mesoscale, around 1-10 km and hourly time scales, the standard metrics used to identify the pressure adjustment mechanism (that involves sea surface temperature, SST, Laplacian and wind divergence) may suffer from this issue, even for weak wind conditions. By exploiting high-resolution realistic numerical simulations with ad hoc SST forcing fields, we introduce some new metrics to evaluate the action of the pressure adjustment atmospheric response to the surface oceanic thermal structures. It is found that the most skillful metrics is based on the wind divergence and SST second spatial derivative evaluated in the across direction of a locally defined background wind field.

Statistical characterization of oceanic flows has been a long standing issue; such information is invaluable for formulating hypotheses and testing them. Another motivation stems from the fact that it allows us to understand the energy pathways within the ocean, which is highly turbulent. Here, we apply the wavelet approach to wavenumber spectral analysis, which has recently been proved to be beneficial in quantifying its spatially heterogeneous and anisotropic nature. We utilize an eddy-rich ensemble simulation of the North Atlantic and examine the spectral transfers of eddy kinetic energy (EKE) and effect of potential energy, here defined via dynamic enthalpy, on the EKE spectral budget. We find that vertical advection of EKE modulates the up- and down-scale direction and strength of EKE spectral flux throughout the North Atlantic domain. The vertical eddy buoyancy flux tends to be small below the mixed layer, suggesting that the flow is largely adiabatic. In maintaining this adiabatic nature, the eddy advection of dynamic enthalpy and practical salinity tend to partially compensate for the eddy advection of potential temperature, a phenomenon similar to the thermodynamic spice variable.

A document by Nina Nesterova. Click on the document to view its contents.

A document by Sara S. Fouad. Click on the document to view its contents.

A document by sebastien_barthelemy. Click on the document to view its contents.

This paper presents an adaptive real-time spectrum data compression and recovery method for radio monitoring, its purpose is to reduce the data storage space and the network bandwidth occupied by transmission without affecting the subsequent analysis and application. Considering the similarity between spectrum data, we use correlation coefficients and bitmap similarity to measure them, and then replace all the original spectrum with a small amount of typical spectrum to achieve the purpose of compressing the original spectrum for storage and compression. The experimental conclusions show that the method can automatically adapt to various radio frequency bands and achieve better compression effects.

Redlining, a historically discriminatory mortgage lending practice, has recently gained attention as a potential cause of public health disparities. However, no study has attempted to synthesize the growing body of research linking redlining to present-day inequalities in access to green space and corresponding environmental health risks. This scoping review aims to provide a comprehensive summary that identifies key characteristics (data, methods, outcomes) and knowledge gaps of current studies exploring the impact of redlining on disproportionate exposure to environmental goods and harms. Using PRISMA guidelines, 21 peer-reviewed articles published between 2020 and 2023 met inclusion criteria. Across included studies, we identified a variety of different study designs (e.g., cross-sectional, longitudinal), outcomes (green space disparity, environmental health inequalities), measures of greenspace (e.g., tree canopy, tree size, NDVI), and environmental health risks (air pollution, extreme heat). The results of this scoping review show that historically redlined neighborhoods have less green space and face greater environmental health risks compared to non-redlined neighborhoods. Although green space and large or mature trees remains scarce in redlined neighborhoods compared to non-redlined neighborhoods, studies show that redlined neighborhoods exhibit a more noticeable increase in tree canopy over time and a higher presence of smaller trees. Disproportionate exposure to air pollution and heat underscores the need for green space planning in redlined neighborhoods that addresses these environmental burdens. Future redlining studies should incorporate additional dimensions of environmental justice, including procedural and recognition justice, to understand the underlying factors perpetuating distributive injustices and identify potential solutions to these health challenges.