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.

Predicting solid particle transport in the lowest parts of the atmosphere is a major issue for man-made obstacles in semi-arid regions. Here, we investigate the effects on solid particle saltation, of rectangular obstacles on the ground with different spacings. The aerodynamic field is determined by large eddy simulations coupled with an immersed boundary method for the obstacles. Solid particles are tracked by a Lagrangian approach. Take-off and rebound models are introduced for the interaction of particles with the wall. Without particles, fluid velocity profiles are first compared with experiments showing good agreement. Special focus is put on the recirculation zone that plays an important role in solid particle entrapment. Particle concentration fields are presented. Accumulation zones are studied regarding the different obstacle spacings as an extension of the aerodynamic scheme by Oke (1988) to solid particle transport. A deposition peak appears before the first obstacle. When the spacing between the two obstacles is large enough, some particles are trapped within the recirculation and a second deposition peak arises. The streamwise evolution of the horizontal saltation flux shows that the lowest flux downstream of the obstacles is obtained for the highest separation. The deposition rate or the streamwise saltation flux are estimated globally as a function of obstacle spacing. These results illustrate how the numerical tool developed here can be used for assessing air quality in terms of solid particle concentration.

A document by Manon Gévaudan. Click on the document to view its contents.

Iron hydrides are a potentially dominant component of the metallic cores of planets, primarily because of hydrogen’s ubiquity in the universe and affinity with iron. Using ab initio molecular dynamics, we examine iron hydrides with 0.1, 0.33, 0.5, and 0.6 mole fraction hydrogen up to 100 GPa between 3000-5000 K to describe how hydrogen content affects the melt structure, hydrogen speciation, equation of state, atomic diffusivity, and melt viscosity. We find that the addition of hydrogen decreases the average Fe-Fe coordination number and lengthens Fe-Fe bonds, while Fe-H coordination number increases. The pair distribution function of hydrogen at low pressure indicates the presence of molecular hydrogen. By tracking chemical speciation, we show that the amount of molecular hydrogen increases and the number of iron in Hx≥1Fey≥0 clusters decreases as hydrogen concentration increases. We parameterize a pressure, volume, temperature, and composition equation of state and show that the molar volume and Grüneisen parameter of the melts decrease while the compressibility and thermal expansivity increase as a function of hydrogen concentration. We find that hydrogen acts as a lubricant in the melts as the iron and hydrogen become more diffusive and the melts become more inviscid as hydrogen concentration increases. We estimate 2.7 wt% hydrogen in the Martian core and 0.49-1.1 wt% hydrogen in Earth’s outer core based on comparisons to seismic models, with the assumption that the cores are pure liquid iron-hydrogen alloy, and we compare the small exoplanet population with mass-radius curves of iron hydride planets.

Differences in slab dehydration and fluid transport influence the distribution of magmatism and seismicity in subduction zones. Southwest Japan, particularly Kyushu and Shikoku/Chugoku, exhibits significant along-arc variation in the spatial distribution of Quaternary arc volcanoes and adakites as well as sub-arc tectonic tremors. Using two-dimensional numerical modeling, we quantitatively evaluate melting and fluid transport via a weak hydrous layer on the slab interface since the subduction initiation to clarify the observed key differences. In Kyushu, our model shows that dehydration of the colder subducting slab is mostly completed at sub-arc depths of 80–120 km, triggering intense flux melting in the mantle wedge without slab melting for adakite and an absence of sub-forearc fluid percolation for tremors. Whereas, the model for Shikoku/Chugoku shows shallower sub-forearc dehydration of the warmer slab (<80 km), allowing less flux melting, slab melting for adakite, and sub-forearc fluid percolation for tremors.

A document by Suleiman Baraka. Click on the document to view its contents.

Radiative heating of clouds, particularly those in the upper troposphere, alters temperature gradients in the atmosphere, affecting circulation and precipitation in today's and future climates. However, the response of cloud radiative heating to global warming remains largely unknown. We study changes to high cloud radiative heating in a warmer climate, identify physical mechanisms responsible for these changes, and develop a theory based on well-understood physics to predict them. Our approach involves a stepwise procedure that builds upon a simple hypothesis of an upward shift in cloud radiative heating at constant temperature and gradually incorporates additional physics. We find that cloud radiative heating intensifies as clouds move upward, suggesting that the role of high clouds in controlling atmospheric circulations increases in a warmer climate.

A document by Jicheng Gu . Click on the document to view its contents.

A document by Natalie Nelson. Click on the document to view its contents.

Abstract All earthquakes over 5th magnitude since 1962 were recorded on Sumatra and surroundings, marking their depths and distinguished whether they were triggered by maximum westward or north-southward tidal torques. Greatest differences were found in period 2003-2009 where earthquakes triggered by north-southward torque were situated on rim of Sumatra continental area on Mentawai Fault. Period 2009-2023 is characteristic by large number of westward tidally triggered earthquakes, situated westward from Sumatra coast reaching sometimes as far as into oceanic lithosphere. As far as the great earthquake M 9.1, 26.12.2004 was triggered by the beat of close tidal frequencies: 19 years Metonic cycle and Moon’s nodal 18.61 years variations and if the beat were symmetric with maximum amplitude 26.12.2004, then because Full Moon will be 27.12.2023 and New Moon 11.1.2024, (Moon’ declinations large +28.1º and -27.6º respectively), the earthquake will occur of 6.5 5th magnitude as similar earthquake 27.12.1985. This prediction has not been fulfilled because the beat has not been symmetric, but asymmetrically shifted by westward tidal torque as proved by absolutely missing earthquakes 25. and 26.12. 2023, documented by very sensitive earthquakes detection up to 2.5 magnitude.

Dotson Ice Shelf has resisted acceleration and ice-front retreat despite high basal-melt rates and rapid disaggregation of the neighboring Crosson Ice Shelf. Because of this lack of acceleration, previous studies have assumed that Dotson is durable. Here we show clear evidence of Dotson's vulnerability as it decelerates, contrary to the common assumption that ice-flow deceleration is synonymous with increased ice-shelf buttressing. Ungrounding of a series of pinning points initiated acceleration in the Upper Dotson in the early 2000s, which subsequently plugged ice flow in the Lower Dotson. Discharge from the tributary Kohler Glacier into Crosson increased, but non-proportionally. Given current surface-lowering rates, we estimate that several remaining pinning points in the Upper Dotson could unground within one to three decades.

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

A document by Chao Song. 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.

Soil moisture is an important factor that affects terrestrial vegetation ecosystems and biological growth and development, and water deficit is one of the major environmental factors threatening vegetation restoration in the Loess Plateau. To determine the change in the soil water deficit characteristics from farmland to forestland on the Loess Plateau, in this study, we measured the soil water storage and deficit in abandoned grassland, shrubland, pioneer forestland and climax forestland along with vegetation succession. The results showed that the soil water content and the soil water storage with natural vegetation recovery from the abandoned grassland to shrubland and forestland showed a gradual declining trend, while on the contrary, the soil water deficit was increasing during succession, it was more severe in the deep soil than in the shallow soil layers, and the soil water deficit in July and September of the rainy season as well as that the vigorous growing period of plants was more serious than that in May and November, which are in the non-rainy season of the Chinese Loess Plateau. The vegetation types, soil texture and soil depth were the key factors affecting the soil water deficiency status in the process of vegetation succession. The results could have great potential in the sustainable development of forestry and provide a theoretical basis for effective water management and reasonable vegetation restoration in arid and semiarid loess regions.

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

Quantification of the magnitude and long-term changes of ozone concentrations transported into the US is important for effective air quality policy development. We synthesize multiple published trend analyses of western US baseline ozone, and show that all results are consistent with an overall, non-linear change – rapid increase during the 1980s that slowed in the 1990s, maximized in the mid-2000s, and was followed by a slow decrease thereafter. This non-linear change accounts for ~2/3 of the variance in the published linear trend analyses; we attribute the other 1/3 to unquantified autocorrelation in the analyzed data sets. Recent systematic changes in baseline ozone at the US West Coast have been relatively small - the standard deviation of the 2-year means over the 1990-2017 period is 1.5 ppb. International efforts to reduce anthropogenic precursor emissions from all northern mid-latitude sources could possibly reduce baseline ozone concentrations, thereby improving US ozone air quality.

Ozonesonde data collected over the western Pacific in the boreal summer of 2021, which is the first continuous, direct ozone observation over the region, were used to investigate the material transport and dynamical variations associated with the summer monsoon and western Pacific convection. The data revealed ozone transport under convectively calm conditions over the western Pacific during the development phase of the Asian summer monsoon. Combining atmospheric reanalysis data and satellite cloud data, the transport process of a high-ozone air mass is described. Near the date line, the air mass intruded from the midlatitude stratosphere into the tropical upper troposphere due to Rossby wave breakings, then moved westward over the Pacific Ocean along 20°N, experiencing nearly adiabatic transport. Subsequently, as it approached the convectively active region of Southeast Asia, it underwent non-conservative mixing with the tropospheric air due to convective processes. The climatological situation in the summer Asia-Pacific region can facilitate frequent occurrences of this type of transport, which may play a role in determining ozone concentration in the tropical upper troposphere.