ALBERT

Description: The ecohydrological separation (EHS) paradigm, frequently compared with the translatory flow (HH), opens up a new understanding of the underlying processes of the terrestrial water cycles. However, the recent finding of deuterium offsets for cryogenic vacuum extraction (CVE) and suggested CVE-bias correction data no longer supports the EHS but goes back to HH. Here we revisited the EHS spurred by the CVE-bias correction with regard to accurate source/xylem water information. We found systematic similarities in the water line (ratio between δ〈sup〉18〈/sup〉O and δ〈sup〉2〈/sup〉H) of plant and soil for a global database, regardless of the suggested CVE-bias correction. This partial CVE-based data correcting from the whole dataset is only applied to correct a random error. Likewise, the correction will not change the slope of the plant water line but its intercept. Furthermore, we outline the key uncertainties that could be quantified for establishing a consistent and combined methodology to correct CVE-bias precisely, although a universal correction function might not exist. Our findings demonstrate a critical misunderstanding in the CVE-bias correction, and suggest a framework to reduce uncertainties for (dis)proving EHS and/or HH across a wide range of water isotope applications.

Description: The state-of-the-art climate models suffer from significant sea surface temperature (SST) bias, greatly damaging the climate prediction and projection. Using a dynamical approach, we investigate the multidecadal mean impacts of SST bias on the simulated atmospheric circulation and variability. A set of century long simulations forced with idealized constant SST perturbations (with the maximal amplitude of 1.5 K), which mimick SST biases in the coupled climate models, are first conducted with an intermediate complexity atmospheric model. The impact of SST bias is then evaluated using the normal-mode function decomposition which can differentiate between balanced and unbalanced flow regimes. The results show that the SST-bias impact depends on the background SST. SST bias in regions with background SSTs ≥ 25°C can result in strong atmospheric circulation bias worldwide, which have the Matsuno-Gill-type pattern in the tropics and Rossby wavetrain distribution in the extratropics. As a result, the simulated spatial and temporal variabilities are strongly affected, and the impacts show distinct geographical dependence. Basically, SST bias in the tropical Indo-west Pacific region (elsewhere) weakens (strengthens) the unbalanced and the tropical (25°S-25°N) balanced spatial variance (energy), and that in the west Pacific (elsewhere) strengthens (weakens) the extratropical balanced spatial variance. As for the temporal variance, it is generally weakened (strengthened) when SST bias is in the tropical Indian Ocean (Pacific), regardless of the flow regime. Finally, the physical causes of the geographic dependence are discussed.

Description: Gravity waves (GW) transport energy and momentum from troposphere upwards into the mesosphere, playing an important role connecting the tropospheric weather with the space weather. The NASA Aeronomy of Ice in the Mesosphere (AIM) satellite was launched in 2007 and provided important GW information within PMC near the mesopause region. The newly developed Rayleigh Albedo Abnormally (RAA) data from The Cloud Imaging and Particle Size (CIPS) instrument measure GWs globally outside the PMC region, at the bottom of the mesosphere (~55 km). As part of the international Antarctica Gravity Wave Instrument Network (ANGWIN) project, Utah State University has been running OH All-Sky Imagers (ASI) for more than 10 years at the Australian Davis station (69°S, 78°E) and the British Rothera Station (68°S, 68°W). High quality night time GW images in OH (3,1) intensity are obtained at the top of the mesosphere (~87 km) during each austral winter seasons. In this study, we will utilize GW data obtained from AIM CIPS and ASI to study the temporal and spatial variation of GWs at these two altitudes and to investigate the small-scale GW propagation characteristics in the high latitude mesosphere.

Description: The Atmospheric Waves Experiment (AWE) is a NASA Mission of Opportunity designed to investigate the near-global properties and effects of gravity waves as they propagate into the Earth’s upper atmosphere. In particular, AWE will measure the spectrum of small-scale (~30-300 km) gravity waves (GWs) generated by strong weather disturbances, e.g., convection and sustained flow over mountains, that impact the ionosphere and thermosphere via the mesosphere. An IR 4-channel imaging system built by the Space Dynamic Lab (SDL) at Utah State University (USU) will be deployed on the International Space Station (ISS) in December 2023. During two years, the AWE instrument will map the nighttime hydroxyl (OH) layer (~87 km), providing 2D gravity wave (GW) fields in mesospheric temperature and OH band intensity over a 600 km field-of-view, every second. The AWE orbit will cover ~85 % of the earth, between ± 55°. The AWE data will be combined with four state-of-the-art models to achieve the AWE science objectives: · Quantify the seasonal and regional variabilities and influences of GWs near the mesopause, · Identify the dominant dynamical processes controlling GWs observed near the mesopause, · Estimate the wider role of GWs in the Ionosphere-Thermosphere-Mesosphere (ITM). This presentation will give an overview of the AWE mission, update current mission status and describe the AWE data levels using synthetic images.

Description: Solute isotopes, such as 〈sup〉87〈/sup〉Sr〈sup〉/86〈/sup〉Sr, δ〈sup〉11〈/sup〉B, δ〈sup〉7〈/sup〉Li and δ〈sup〉44/40〈/sup〉Ca, have been widely used to trace the sources of dissolved solutes in water, because of the large isotopic variation of the potential sources. Sorption–desorption and ion exchange commonly occur in a water–rock system that contains clay. However, the contribution or the impact of sorption–desorption and ion exchange on isotopic composition of water have not been well identified. Shale is enriched in clay and comprehensive sorption–desorption and ion exchange occurs within a short time. Accordingly, the flowback water following hydraulic fracturing of shale gas reservoirs is a unique material for studying the mechanism affecting the specific isotopic composition (〈sup〉87〈/sup〉Sr/〈sup〉86〈/sup〉Sr, δ〈sup〉11〈/sup〉B, δ〈sup〉7〈/sup〉Li and δ〈sup〉44/40〈/sup〉Ca). This study also determined all potential endmembers (concentration and isotopic composition/ratio for water-soluble fraction, exchangeable fraction, and carbonate minerals). The results showed that desorption of B and Li from shale rock, isotopic re-equilibrium between the dissolved Sr and exchangeable Sr, and isotopic fractionation during cation exchange (〈sup〉40〈/sup〉Ca was favored over 〈sup〉44〈/sup〉Ca) mainly controlled the specific isotopic composition of flowback water beyond mixing between fracturing fluids and local formation water. However, the increases in 87Sr/86Sr ratios were previously interpreted as the dissolution of silicates with a high 87Sr/86Sr ratio. While clay minerals are commonly distributed in most water–rock systems and the findings of this study are important and useful for tracing water–rock interactions and sources of specific solutes in water systems that could be impacted by asorption-desorption and ion exchange.

Description: Growth in satellite observations and modelling capabilities has transformed drought monitoring, offering near-real-time information. However, current monitoring efforts focus on hazards rather than impacts, and are further disconnected from drought-related compound or cascading hazards such as heatwaves, wildfires, floods and debris flows. In this Perspective, we advocate for impact-based drought monitoring and integration with broader drought-related hazards. Impact-based monitoring will go beyond top-down hazard information, linking drought to physical or societal impacts such as crop yield, food availability, energy generation or unemployment. This approach, specifically forecasts of drought event impacts, would accordingly benefit multiple stakeholders involved in drought planning, and risk and response management, with clear benefits for food and water security. Yet adoption and implementation is hindered by the absence of consistent drought impact data, limited information on local factors affecting water availability (including water demand, transfer and withdrawal), and impact assessment models being disconnected from drought monitoring tools. Implementation of impact-based drought monitoring thus requires the use of newly available remote sensors, the availability of large volumes of standardized data across drought-related fields, and the adoption of artificial intelligence to extract and synthesize physical and societal drought impacts.

Description: Intramolecular carbon isotope profiles (13C/12C) of mid- and long-chain saturated fatty acids represent a potentially rich source of pathway and flux information on fatty lipid biosynthesis. Accessing the PSIC-13C (position-specific carbon isotope composition) of saturated long chain fatty acids, however, proves a challenge as neither 13C NMR, nor online pyrolysis, can measure all carbons successfully. We have developed a wet chemistry procedure (α-bromination, α-hydrolysis and decarboxylation) to stepwise shorten the targeted saturated fatty acid, followed by GC/C/IRMS (gas chromatography/combustion/isotope ratio mass spectrometry) measurement of the 13C/12C ratios of fatty acids, with minimal purification. Isotope mass balance was then applied to calculate the 13C/12C ratios of individual carbons. The triplicated PSIA precision varies from position to position in the range 3.95–5.25 mUr (averaging 4.44 mUr, equivalent to ‰). Applying this method to a commercial C16:0 fatty acid of C3 botanical origin revealed an intramolecular odd-over-even 13C enrichment pattern, consistent with that obtained with 13C NMR. Although PSIA-13C was attempted only on a single fatty acid, the method can potentially be applied to obtain PISC-13C for all fatty acids in a mixture simultaneously, and to long chain saturated alkanes after proper functionalization. The method should prove useful in studies of lipid metabolism and biogeochemistry as both saturated long chain fatty acids and alkanes are the dominant organic archives of climate in petroleum deposits, sediments and soils.

Description: Qongjiagang pegmatite-type Li deposit in Tibet is the first discovered pegmatite-type deposit with economic value in the Himalayan region, which confirms that the Himalayan region has the potential to become a strategic base of rare metal in China, and provide indications to find pegmatite-type Li deposit in the Himalayan region. In this study, we use SEM to identify the type, frequency and occurrence (relationship with cracks) of mineral inclusions in the three main accessory minerals, monazite, apatite and zircon from granite and pegmatite of Qongjiagang Li deposit, combining with the EPMA analysis of feldspar inclusions in apatite to comprehensively trace the property and evolution of the melts and fluids. Our study indicates that: (1) the main mineral inclusions in monazite, apatite and zircon from Qongjiagang Li deposit include silicate, oxide, phosphates and a small amount of sulfide, not only the REE-rich monazite and apatite filling or intersecting cracks are formed by hydrothermal alteration, but also the uraninite and thorianite isolated from cracks occur in the self-irradiation region of zircon are related to fluids; (2) the appearances of columbite and pyrochlore inclusions in the apatite from tourmaline-muscovite granite demonstrate that the initial melt is enriched in Nb and Ta, the amount and type of rare metal mineral inclusions can be used as an indicator for rare metal mineralization in highly evolved granite and pegmatite; (3) the plagioclase inclusions with high and a large range of An values in apatite from spodumene pegmatite represent the capture of less-differentiated melt and continuously fractional crystallization. Our results indicate that the types and compositions of mineral inclusions in accessory minerals can be good tracers for the characteristics and evolution of melts and fluids in the highly evolved granite-pegmatite system

Description: Carbon-13 position-specific isotope analysis of fatty acids from vegetable oils was performed using Nuclear Magnetic Resonance in the present study. The measured 13C patterns are not totally in accordance with the conventional view of the relative 13C-depletion of acetogenic lipids and their alternation of 13C-enriched and 13C-depleted carbon positions. The results presented here provide a new evaluation of the isotopic fractionation associated with fatty acids biosynthesis. Whereas it is commonly acknowledged that the pyruvate dehydrogenase (PDH) is responsible for the 13C distribution within fatty acids, data from the present work demonstrate that the conversion of acetyl-CoA to malonyl-CoA catalyzed by acetyl-CoA carboxylase (ACC) needs to be considered while explaining the measured non-stochastic 13C pattern within fatty acids. These data combined with steady-state calculations give a new description of metabolic steps responsible for the typical 13C intramolecular distribution of acetogenic lipids. In addition, the non-stochastic pattern measured in these plant fatty acids is similar to those previously detected within long-chain n-alkanes suggesting a preservation through geological time and demonstrating the interest of position-specific isotope analysis for studying the evolution of metabolic pathways.

Description: In this study, based on the cloud-top height (CTH) data and lightning detector (LMI) data acquired by the AGRI detector on board the FY-4A geostationary satellite, the LMI data were processed using the cluster analysis method, and the cloud-top height data of thunderstorms were quality controlled based on CALIPSO data. Convective systems in different regions over land and adjacent seas in China were identified, datasets of thunderstorms and penetrating convection were obtained, and the characteristics of cloud-top height and lightning activity of thunderstorms (TS) and overshooting convection (OC) and their relationships were analyzed. The results show that the ratio of the number of OCs to the number of TSs is 12.3% on average in different regions on land, while the ratio is 24.85% in oceanic regions, indicating that thunderstorms in the ocean are more likely to evolve into penetrating convection; most thunderstorms with CAPE〈sup〉1/2〈/sup〉 and CTH are mainly concentrated in the regions with 15 ms〈sup〉-1〈/sup〉 〈 CAPE〈sup〉1/2〈/sup〉 〈 50 ms〈sup〉-1〈/sup〉 and 11 km 〈 CTH 〈 17.5 km. region, and most of the updraft velocities and CTHs in OC were mainly concentrated in the region of 20 ms〈sup〉-1〈/sup〉 〈 CAPE〈sup〉1/2〈/sup〉 〈 50 ms〈sup〉-1〈/sup〉 and 15 km 〈 CTH 〈 19 km. For both thunderstorms and overshooting convection, lower updrafts produce lower lightning rates (characterization by flash extent density, FED) and larger lightning horizontal scales (characterization by minimum flash area, MFA); conversely, larger updrafts produce higher lightning rates and smaller lightning horizontal scales.