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Hot flow anomalies (HFAs) and foreshock bubbles (FBs) are two types of transient phenomena characterized by flow deflected and hot cores bounded by one or two compressional boundaries in the foreshock. Using conjunction observations by the Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission, we present an MHD HFA with a core filled with magnetosheath material around the bow shock and a typical kinetic FB associated with foreshock ions upstream of the bow shock, occurring simultaneously under the same solar wind/interplanetary magnetic field (IMF) conditions. The displacements of the bow shock moving back and forth along the sun-earth line are observed. Electron energy shows enhancements from ∼50 keV in the FB to ∼100 keV in the HFA core, suggesting additional acceleration process across the bow shock within the transient structure. The magnetosheath response of an HFA core-like structure with particle heating and electron acceleration is observed by the Magnetospheric Multiscale (MMS) mission. Ultralow frequency waves in the magnetosphere modulating cold ion energy are identified by THEMIS, driven by these transient structures. Our study improves our understanding of foreshock transients and suggests that single spacecraft observations are insufficient to reveal the whole picture of foreshock transients, leading to an underestimation of their impacts (e.g., particle acceleration energy and spatial scale of disturbances). 

ABSTRACT China's pursuit of carbon neutrality targets hinges on a profound shift towards low-carbon energy, primarily reliant on intermittent and variable, yet crucial, solar and wind power sources. In particular, low-solar-low-wind (LSLW) compound extremes present a critical yet largely ignored threat to the reliability of renewable electricity generation. While existing studies have largely evaluated the impacts of average climate-induced changes in renewable energy resources, comprehensive analyses of the compound extremes and, particularly, the underpinning dynamic mechanisms remain scarce. Here we show the dynamic evolution of compound LSLW extremes and their underlying mechanisms across China via coupling multi-model simulations with diagnostic analysis. Our results unveil a strong topographic dependence in the frequency of compound LSLW extremes, with a national average frequency of 16.4 (10th–90th percentile interval ranges from 5.3 to 32.6) days/yr, when renewable energy resources in eastern China are particularly compromised (∼80% lower than that under an average climate). We reveal a striking increase in the frequency of LSLW extremes, ranging from 12.4% under SSP126 to 60.2% under SSP370, primarily driven by both renewable energy resource declines and increasingly heavily-tailed distributions, resulting from weakened meridional temperature (pressure) gradient, increased frequency of extremely dense cloud cover and additional distinctive influence of increased aerosols under SSP370. Our study underscores the urgency of preparing for significantly heightened occurrences of LSLW events in a warmer future, emphasizing that such climate-induced compound LSLW extreme changes are not simply by chance, but rather projectable, thereby underscoring the need for proactive adaptation strategies. Such insights are crucial for countries navigating a similar transition towards renewable energy. 

Abstract Multidecadal variability of the Indonesian Throughflow (ITF) is crucial for the Indo-Pacific and global climate due to significant interbasin exchanges of heat and freshwater. Previous studies suggest that both wind and buoyancy forcing may drive ITF variability, but the role of precipitation and salinity effect in the variability of ITF on multidecadal time scales remains largely unexplored. Here, we investigate the multidecadal changes and long-term trend of the ITF transport during the past six decades, with a focus on the role of precipitation and salinity effect. The diverse datasets consistently indicate a substantial upward trend in the halosteric component of geostrophic transport of ITF in the outflow region at 114°E during the six decades. We find that the meridional differences of the salinity trend in the outflow region explain the increasing trend of the halosteric component of ITF transport. On a larger scale, the tropical western Pacific Ocean and Indonesian seas have experienced significant freshening, which has strengthened the Indo-Pacific pressure gradient and thus enhanced the ITF. In contrast, the equatorial trade wind in the western Pacific Ocean has weakened over recent decades, implying that changes in wind forcing have contributed to weakening the ITF. The combined effect of strengthened halosteric and weakened thermosteric components has resulted in a weak strengthening for the total ITF with large uncertainties. Although both the thermosteric and halosteric components are associated with natural climate modes, our results suggest that the importance of salinity effect is likely increasing given the enhanced water cycle under global warming. 

Pregnancy brings physical, emotional, and economic challenges for expectant parent(s), close relatives, and friends. Existing technology support, including tracking technology, largely targets pregnant people and ignores other stakeholders. We therefore lack an understanding of how to approach designing collaborative pregnancy tracking technology. To understand how people collaborate around pregnancy tracking and wish to do so, we interviewed 13 pregnant people and 11 non-pregnant stakeholders in the U.S., including partners, friends, and grandparents-to-be. We find that people collaborate for goals like social bonding and jointly managing various pregnancy data. Stakeholders collaborated by either dividing up data types or collectively monitoring the same information. We also identify tensions and challenges, such as pregnant people’s privacy concerns and stakeholders’ varied levels of interest in tracking. In light of socio-cultural norms and stakeholders’ distinctive roles around pregnancy, we point to opportunities for designing collaborative technology that aligns with as well as challenges socio-cultural practices around pregnancy tracking. 

Pregnancy is a significant but stressful life transition, requiring effort from multiple stakeholders including expectant parents, family members, and friends to navigate. Existing work has primarily focused on understanding and supporting the technology use of pregnant people, neglecting other stakeholders' needs and participation. We therefore consider how pregnancy tracking apps both improve and interfere with the reconfiguration of social relationships caused by pregnancy, drawing on insights from family sociology to examine how these relationships evolve over pregnancy and the transition to parenthood. We reviewed the features of 20 pregnancy tracking apps, and analyzed 4,709 public reviews of them, finding that stakeholders used apps to bond with one another around the excitement of pregnancy, build a prenatal relationship with the fetus, and co-manage pregnancy-related logistical tasks. We find that not accounting for fetal demographics and users' identities, along with socio-cultural norms around gender and parenting roles, often inhibit these collaborative practices. We therefore suggest designing collaborative pregnancy tracking technology that considers both inclusiveness and specificity regarding stakeholders' different roles and relationships to pregnancy. 

Abstract The Makassar Strait throughflow (MST) constitutes a significant component of the Indonesian throughflow (ITF) and plays a pivotal role in the interbasin exchange between the Indian and Pacific Oceans. While previous studies have suggested that the buoyancy forcing plays a role in influencing the seasonality of the MST, the quantitative contribution of salinity effect on MST seasonality remains unclear. Here we use the measurements from the Monitoring ITF program and the Global Ocean Physics Reanalysis product to investigate the seasonality of MST and quantify the impact of the salinity effect. We find that the halosteric variability due to the salinity effect contributes to approximately (69.6 ± 11.7) % of the total seasonal variability of surface dynamic height gradient along the Makassar Strait, and dominates the seasonality of the upper layer MST. The primary drivers for freshwater forcing are horizontal advection through the Karimata Strait and precipitation in the Java Sea. 

The respective benefits and drawbacks of manual food journaling and automated dietary monitoring (ADM) suggest the value of semi-automated journaling systems combining the approaches. However, the current understanding of how people anticipate strategies for implementing semi-automated food journaling systems is limited. We therefore conduct a speculative survey study with 600 responses, examining how people anticipate approaches to automatic capture and prompting for details. Participants feel the location and detection capability of ADM sensors influences anticipated physical, social, and privacy burdens. People more positively anticipate prompts which contain information relevant to their journaling goals, help them recall what they ate, and are quick to respond to. Our work suggests a tradeoff between ADM systems' detection performance and anticipated acceptability, with sensors on facial areas having higher performance but lower acceptability than sensors in other areas and more usable prompting methods like those containing specific foods being more challenging to produce than manual reminders. We suggest opportunities to improve higher-acceptability, lower-accuracy ADM sensors, select approaches based on individual and practitioner journaling needs, and better describe capabilities to potential users. 

The moderate DI13C isotope enrichment (MoDIE) method by Powers et al. (2017) is a promising method to precisely measure the photochemical mineralization of dissolved organic carbon (DOC) in water samples without dramatically altering a sample's pH or organic carbon pool. Here, we evaluated the analytical uncertainties of the MoDIE method and used Monte Carlo simulations to optimize the experimental design for the most precise measurements of dissolved inorganic carbon (DIC) that is produced photochemically (DIChν). Analytically, we recommend calculating yields of DIChv with an exact expression of conservation of mass that intrinsically reduces error and uncertainty. Methodologically, the overall uncertainty and detection limit of the MoDIE method can be significantly reduced by partially stripping away the original DIC pool, enriching the residual DIC with more DI13C, and increasing the yields of DIChv via longer irradiation. Instrumentally, more precise measurements of enriched δ13C values before and after irradiation are needed to further improve the precision of DIChν concentration determinations. Higher precision DIChv measurements via the optimized MoDIE method can improve our understanding of the photochemical mineralization of DOC and thus the budget of marine DOC. The optimizations and detection limits reported here will become more refined as measurements and associated uncertainties from future MoDIE experiments become available.