▶ Gathers original articles on topics in earth and planetary sciences ▶ Coverage includes geomagnetism, aeronomy, space science, seismology, volcanology, geodesy and planetary science ▶ Official journal of the Society of Geomagnetism and Earth, Planetary and Space Sciences, The Seismological Society of Japan, The Volcanological Society of Japan, The Geodetic Society of Japan, and The Japanese Society for Planetary Sciences

「Earth,Planets and Space」のオープンアクセス出版

Abstract HUmic-LIke Substances (HULIS) comprise a significant fraction of the water-soluble organic aerosol mass and influence the water uptake properties of aerosols in the atmosphere. In this work, the abundance and size distributions of HULIS in ambient aerosols were measured in a rural location in South China at a time with a visible presence of crop residue burning. PM 2.5 samples of fresh smoke from burning rice straw and sugar cane leaves were also collected and analyzed for HULIS and major aerosol constituents. HULIS were abundant in both ambient samples and in fresh biomass burning emissions, accounting for ∼60% of the water-soluble organic carbon in the ambient aerosols and ∼30% in the fresh biomass burning aerosols. In the particles in the range of 0.32–1.8 μm, the abundance of HULIS was 40–90% of the combined abundance of sulfate and ammonium, suggesting that HULIS should be considered when quantifying the role of sulfate aerosols serving as cloud condensation nuclei. The size distribution of HULIS was characterized by a dominant droplet mode with a mass median aerodynamic diameter (MMAD) in the range of 0.63–0.87 μm, accounting for 81% of the total HULIS mass, a minor condensation mode (12%, MMAD: 0.23–0.28 μm) and a coarse mode (7%, MMAD: 4.0–5.7 μm). The small amount of HULIS in the coarse mode indicated that soil-derived HULIS was a very minor source. On the basis of the size distribution characteristics, HULIS were postulated to have multiple sources, including secondary formation in cloud droplets, secondary formation through heterogeneous reactions or aerosol-phase reactions, and primary emissions from biomass burning.

Size Distribution of HULIS in Ambient Aerosols at a Rural Site in South China

Fugitive road dust (FRD) particles emitted by traffic-generated turbulence are an important contributor to urban ambient fine particulate matter (PM2.5). Especially in urban areas of developing countries, FRD PM2.5 emissions are a serious environmental threat to air quality and public health. FRD PM2.5 emissions have been neglected or substantially underestimated in previous study, resulting in the underestimation of modeling PM concentrations and estimating their health impacts. This study constructed the FRD PM2.5 emissions inventory in a major inland city in China (Lanzhou) in 2017 at high-resolution (500 × 500 m2), investigated the spatiotemporal characteristics of the FRD emissions in different urban function zones, and quantified their health impacts. The FRD PM2.5 emission was approximately 1141 ± 71 kg d-1, accounting for 24.6% of total PM2.5 emission in urban Lanzhou. Spatially, high emissions exceeding 3 × 104 μg m-2 d-1 occurred over areas with smaller particle sizes, larger traffic intensities, and more frequent construction activities. The estimated premature mortality burden induced by FRD PM2.5 exposure was 234.5 deaths in Lanzhou in 2017. Reducing FRD emissions are an important step forward to protect public health in many developing urban regions.

Fugitive Road Dust PM2.5 Emissions and Their Potential Health Impacts.

This study reports on heterogeneous ice nucleation activity of predominantly organic (or coated with organic material) anthropogenic particles sampled within and around the polluted environment of Mexico City. The onset of heterogeneous ice nucleation was observed as a function of particle temperature (Tp), relative humidity (RH), nucleation mode, and particle chemical composition which is influenced by photochemical atmospheric aging. Particle analyses included computer controlled scanning electron microscopy with energy dispersive analysis of X-rays (CCSEM/EDX) and scanning transmission X-ray microscopy with near edge X-ray absorption fine structure spectroscopy (STXM/NEXAFS). In contrast to most laboratory studies employing proxies of organic aerosol, we show that anthropogenic organic particles collected in Mexico City can potentially induce ice nucleation at experimental conditions relevant to cirrus formation. The results suggest a new precedent for the potential impact of organic particles on ice cloud formation and climate.

Heterogeneous nucleation of ice on anthropogenic organic particles collected in Mexico City

Clinical experience suggests increased incidences of neonatal jaundice when air quality worsens, yet no studies have quantified this relationship. Here we reports investigations in 25,782 newborns showing an increase in newborn’s bilirubin levels, the indicator of neonatal jaundice risk, by 0.076 (95% CI: 0.027–0.125), 0.029 (0.014–0.044) and 0.009 (95% CI: 0.002–0.016) mg/dL per μg/m3 for PM2.5 exposure in the concentration ranges of 10–35, 35–75 and 75–200 μg/m3, respectively. The response is 0.094 (0.077–0.111) and 0.161 (0.07–0.252) mg/dL per μg/m3 for SO2 exposure at 10–15 and above 15 μg/m3, respectively, and 0.351 (0.314–0.388) mg/dL per mg/m3 for CO exposure. Bilirubin levels increase linearly with exposure time between 0 and 48 h. Positive relationship between maternal exposure and newborn bilirubin level is also quantitated. The jaundice−pollution relationship is not affected by top-of-atmosphere incident solar irradiance and atmospheric visibility. Improving air quality may therefore be key to lowering the neonatal jaundice risk. Air pollution has become a major health risk in China. Here Zhang et al. report that maternal and neonatal exposure to particulate matter increases the risk of neonatal jaundice based on the study of 25,782 newborns born in China between 2014 and 2017.

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Air pollution exposure associates with increased risk of neonatal jaundice.

Ultrasound examination is widely used in the clinical diagnosis of thyroid nodules (benign/malignant). However, the accuracy relies heavily on radiologist experience. Although deep learning techniques have been investigated for thyroid nodules recognition. Current solutions are mainly based on static ultrasound images, with limited temporal information used and inconsistent with clinical diagnosis. This paper proposes a novel method for the automated recognition of thyroid nodules through an exhaustive exploration of ultrasound videos and key-frames. We first propose a detection-localization framework to automatically identify the clinical key-frame with a typical nodule in each ultrasound video. Based on the localized key-frame, we develop a key-frame guided video classification model for thyroid nodule recognition. Besides, we introduce a motion attention module to help the network focus on significant frames in an ultrasound video, which is consistent with clinical diagnosis. The proposed thyroid nodule recognition framework is validated on clinically collected ultrasound videos, demonstrating superior performance compared with other state-of-the-art methods.

Key-frame Guided Network for Thyroid Nodule Recognition using Ultrasound Videos

Optimal deployment of seafloor observation network for tsunami data assimilation in the South China Sea

. On 4 March 2021, two tsunamigenic earthquakes ( M w 7.4 and M w 8.1) occurred successively within 2 h in the Kermadec Islands, offshore New Zealand. We ex-amined sea level records at tide gauges located at ∼ 100 to ∼ 2000 km from the epicenters, conducted Fourier and wavelet analyses as well as numerical modeling of both tsunamis. Fourier analyses indicated that the energy of the ﬁrst tsunami is mainly distributed over the period range of 5–17 min, whereas it is 8–32 min for the second tsunami. Wavelet plots showed that the oscillations of the ﬁrst tsunami continued even after the arrival of the second tsunami. As the epicenters of two earthquakes are close to each other ( ∼ 55 km), we reconstructed the source spectrum of the second tsunami by using the ﬁrst

Characteristics of two tsunamis generated by successive M w 7.4 and M w 8.1 earthquakes in the Kermadec Islands on 4 March 2021

Determining the cooling magnitude in the east of China during the Last Glacial Maximum using a degree-day model

Melting and evolution of Arctic Ocean sea ice in summer are one of the main factors affecting sea ice albedo and climate. At present, remote sensing images of sea ice are mainly acquired with the help of payload platforms, such as aircraft or satellites. The above methods have a large measurement scale and a short period. Sea ice research also requires suitable equipment for fine-scale, visualized long-term tracking observations of target sea ice regions. This article investigates the feasibility of measuring interannual variability in sea ice morphology in the Arctic sea ice environment using a low-power gimbal camera automated by satellite communications. Year-round observational data from the arctic field were used. The sea ice images were defogged and edge-enhanced by a newly developed algorithm with the help of human visual enhancement principles. During the 11th Chinese National Arctic Science Expedition, the system was placed on perennial ice in the northern Beaufort Basin to monitor sea ice appearance changes and the external state of the ice mass balance buoy. The system fuses visually enhanced sea ice images with ice balance buoy data from the same ice floe in a multi-scale environmental sequence to obtain sea ice observations with image sequences. The data complement the need for long-duration, fixed-ice, and short-visual-range observations in sea-ice studies. The equipment design methods and image processing algorithms involved in the experimental process have accumulated engineering experience for this application area. The research methodology provides a new framework for long-term, and visualized sea ice observation methods.

Yuchen Wang

Papers

Key-frame Guided Network for Thyroid Nodule Recognition using Ultrasound Videos

Optimal deployment of seafloor observation network for tsunami data assimilation in the South China Sea

Characteristics of two tsunamis generated by successive M w 7.4 and M w 8.1 earthquakes in the Kermadec Islands on 4 March 2021

Determining the cooling magnitude in the east of China during the Last Glacial Maximum using a degree-day model

Feasibility Study for an Ice-Based Image Monitoring System for Polar Regions Using Improved Visual Enhancement Algorithms