Auroral Research Articles

The response of photosynthesis to temperature and irradiance in a green alga, Ryuguphycus kuaweuweu (Ulvales) reveals adaptation to a subtidal environment in the northern Ryukyu Islands

We investigated the photosynthetic response of Ryuguphycus kuaweuweu (=Umbraulva kuaweuweu, Ulvales), a subtidal green alga from the northern Ryukyu Islands (35–40 m deep), Kagoshima, Japan, to temperature, irradiance, and light spectral limitation using a pulse amplitude modulation (PAM)-chlorophyll fluorometer and dissolved oxygen sensors. The photochemical efficiency in photosystem II (maximum quantum yield, Fv/Fm and effective quantum yield, ΔF/Fm′) response during 3-day temperature exposure (8–40 °C) revealed that Fv/Fm, measured in darkness, was not significantly affected by temperatures below 32 °C. In contrast, ΔF/Fm′ measured at 50 μmol photons m−2 s−1 was sensitive to temperature and showed an optimum temperature of 26.1 °C. The gross photosynthesis (GP rate, 8–40 °C) at 200 μmol photons m−2 s−1 showed that the maximum GP rate occurred at 29.5 °C. The photosynthesis–irradiance (P–E) responses (0–1000 μmol photons m−2 s−1) measured at 12, 20, and 28 °C showed that the net photosynthesis quickly saturated at low irradiance levels. However, as temperature increased, the irradiances required for photosynthetic saturation also increased. Additionally, the P–E curves obtained under blue (450 nm), green (525 nm), red (660 nm), and white (metal halide lamp) lights indicated that this alga exhibited higher levels of maximum photosynthetic output under blue and green lights. We further observed that during continuous 6-h exposure to irradiance levels of 100, 200, 500, and 1000 μmol photons m−2 s−1 at 20 °C, ΔF/Fm′ decreased progressively as the irradiance levels increased. At 100 μmol photons m−2 s−1 and 12, 20, and 28 °C, the ΔF/Fm′ was stable at 20 and 28 °C but declined at 12 °C, suggesting the occurrence of low temperature-light stress. In conclusion, the results suggest that R. kuaweuweu is adapted to the study site's subtidal temperature and light environments where green and blue wavelengths can effectively penetrate.

Scientific echosounder data provide a predator’s view of Antarctic krill (Euphausia superba)

Raw acoustic data were collected in East Antarctica from the RSV Aurora Australis during two surveys: the Krill Availability, Community Trophodynamics and AMISOR Surveys (KACTAS) and the Krill Acoustics and Oceanography Survey (KAOS) in the East Antarctic (centre coordinate 66.5° S, 63° E). The KACTAS survey was conducted between 14th to 21st January and 2001, and the KAOS survey was conducted between 16 January and 1 February 2003. We examine the Antarctic krill (Euphausia superba) component of these surveys and provide scientific echosounder (EK500 and EK60) data collected at 38, 120 and 200 kHz, cold water (−1 °C) echosounder calibration parameters and accompanying krill length frequency distributions obtained from trawl data. We processed the acoustic data to apply calibration values and remove noise. The processed data were used to isolate echoes arising from swarms of krill and to estimate metrics for each krill swarm, including internal density and individual swarm biomass. The krill swarm data provide insights to a predators’ views of krill distribution and density.

Aurora Classification in All-Sky Images via CNN–Transformer

An aurora is a unique geophysical phenomenon with polar characteristics that can be directly observed with the naked eye. It is the most concentrated manifestation of solar–terrestrial physical processes (especially magnetospheric–ionospheric interactions) in polar regions and is also the best window for studying solar storms. Due to the rich morphological information in aurora images, people are paying more and more attention to studying aurora phenomena from the perspective of images. Recently, some machine learning and deep learning methods have been applied to this field and have achieved preliminary results. However, due to the limitations of these learning models, they still need to meet the requirements for the classification and prediction of auroral images regarding recognition accuracy. In order to solve this problem, this study introduces a convolutional neural network transformer solution based on vision transformers. Comparative experiments show that the proposed method can effectively improve the accuracy of aurora image classification, and its performance has exceeded that of state-of-the-art deep learning methods. The experimental results show that the algorithm presented in this study is an effective instrument for classifying auroral images and can provide practical assistance for related research.

Aurora Borealis over Tarbat Ness lighthouse

WeatherVolume 78, Issue 5 p. E1-E1 Inside Cover Photograph Aurora Borealis over Tarbat Ness lighthouse First published: 16 May 2023 https://doi.org/10.1002/wea.4405Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL No abstract is available for this article. Volume78, Issue5May 2023Pages E1-E1 RelatedInformation

Aurora Borealis over Wester Ross, Highland

WeatherVolume 78, Issue 5 p. E2-E2 Inside Cover Photograph Aurora Borealis over Wester Ross, Highland First published: 16 May 2023 https://doi.org/10.1002/wea.4406Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL No abstract is available for this article. Volume78, Issue5May 2023Pages E2-E2 RelatedInformation

A High Parameter Flow Cytometric Assay to Identify Human Myeloid Derived Suppressive Cells

Abstract The concept of myeloid derived suppressive cells (MDSCs) has emerged in recent years as a group of myeloid cells that pocess potent immunosuppressive activity. These cells expand under pathologic conditions and suppress the immune functions of T cells, dendritic cells, macrophages, and natural killer cells. They have been shown to be involved in the pathological states of cancer, autoimmune diseases, and infections, such as COVID-19. MDSCs are subset into PMN (polymorphonuclear)- and M (monocytic)-MDSCs. Phenotypic markers of MDSCs have been elucidated in recent years. Here Cytek® developed a 14-color, 16-marker, single-tube flow cytometric assay to analyzed MDSCs. The panel includes markers to exclude lymphoid lineage cells, and markers to identify PMN-MDSC and M-MDSC populations, such as CD15, CD14, CD16, CD66b, CD11b and HLA-DR. In addition, PMN- and M-MDSC specific expression markers such as Lox-1, CXCR-1, DR5 are also included. Fresh whole blood samples were stained with erythrocyte lyse wash method and the samples were analyzed on a Cytek® Aurora or 3-laser Northern Light TMinstrument. The panel performance was evaluated on blood samples collected in EDTA, Heparin, ACD, and Cytochex blood tubes as well as peripheral blood mononuclear cell (PBMC) samples. Assay precision was assessed by testing on 12 donor samples in triplicates on three consecutive days. Targeted cell populations are well identified in peripheral blood and PBMC samples with good resolution and assay precision with %CV less than 25% for all cell populations of interests. This 14-color 16-marker preoptimized flow cytometric assay can be used in clinical research and drug discovery in cancer, autoimmune diseases, infections and other inflammatory diseases.

Extracts from Acta Literaria et Scientiarum Sveciæ, Volumen Quartum (1735–1739)

The file is a facsimile of extracts from the fourth volume of the Acta Literaria et Scientiarum Sveciae, comprising all articles on the aurora borealis in issues of the journal covering the years 1735 to 1739. For a detailed summary of contents, see the introduction by Per Pippin Aspaas.

Introduction

The sixteenth volume in the series presents all articles on the aurora borealis that were published in the journal of the Swedish Societas Regia Literaria et Scientiarum (now Kungl. Vetenskaps-Societeten i Uppsala) from 1730 to 1739. The articles are by the society’s secretary, the professor of astronomy in Uppsala, Anders (in Latin: Andreas) Celsius and by several other Swedish professionals and amateurs of science. In the introduction to this volume, neo-Latinist and historian of science Per Pippin Aspaas summarizes the contents of all articles dealing with the aurora and presents extracts of these texts in English translation. He also provides a short history of the society in the period and gives brief presentations of Anders Celsius, Herman Spöring, Sven Hof, Johan Göstaf Hallman, Johan Sparschuch and Nils Wallerius as auroral researchers.

Extracts from Acta Literaria et Scientiarum Sveciæ, Volumen Tertium (1730–1734)

The file is a facsimile of extracts from the third volume of the Acta Literaria et Scientiarum Sveciae, comprising all articles on the aurora borealis in issues of the journal covering the years 1730 to 1734. For a detailed summary of contents, see the introduction by Per Pippin Aspaas.

Illuminating dinosaurs under the aurora borealis-A commentary on the creation of the Arctic cover for Dinosaurs: New Ideas from Old Bones.

Illuminating dinosaurs under the aurora borealis-A commentary on the creation of the Arctic cover for Dinosaurs: New Ideas from Old Bones.

Front Cover: Ruthenium‐Assisted Tellurium Abstraction in Bis(thiophen‐2‐yl) Ditelluride (Eur. J. Inorg. Chem. 14/2023)

The Front Cover shows the reaction of [RuCl2(CO)3]2 and Te2Tpn2 (Tpn=thiophen-2-yl) in dichloromethane. The dark winter night in the North, which is dimly illuminated by northern lights, illustrates that [RuCl2(CO)3]2 catalyzes the decomposition of Te2Tpn2 to TeTpn2 and elemental tellurium even in the absence of light, as shown on the right side of the picture. [RuCl2(CO)3]2 is a bifunctional reagent and reacts concurrently with the monotelluride, forming the cct-[RuCl2(CO)2(TeTpn2)2] [cis(Cl)-cis(CO)-trans(TeTpn2)] complex, as shown on the left side of the picture. The reactions were followed by NMR spectroscopy and modeled with the help of theoretical calculations. More information can be found in the Research Article by R. Oilunkaniemi, R. S. Laitinen and co-workers.

Reducing Southern Ocean Shortwave Radiation Errors in the ERA5 Reanalysis with Machine Learning and 25 Years of Surface Observations

Abstract Earth system models struggle to simulate clouds and their radiative effects over the Southern Ocean, partly due to a lack of measurements and targeted cloud microphysics knowledge. We have evaluated biases of downwelling shortwave radiation in the ERA5 climate reanalysis using 25 years (1995–2019) of summertime surface measurements, collected on the Research and Supply Vessel (RSV) Aurora Australis, the Research Vessel (R/V) Investigator, and at Macquarie Island. During October–March daylight hours, the ERA5 simulation of SWdown exhibited large errors (mean bias = 54 W m−2, mean absolute error = 82 W m−2, root-mean-square error = 132 W m−2, and R2 = 0.71). To determine whether we could improve these statistics, we bypassed ERA5’s radiative transfer model for SWdown with machine learning–based models using a number of ERA5’s gridscale meteorological variables as predictors. These models were trained and tested with the surface measurements of SWdown using a 10-fold shuffle split. An extreme gradient boosting (XGBoost) and a random forest–based model setup had the best performance relative to ERA5, both with a near complete reduction of the mean bias error, a decrease in the mean absolute error and root-mean-square error by 25% ± 3%, and an increase in the R2 value of 5% ± 1% over the 10 splits. Large improvements occurred at higher latitudes and cyclone cold sectors, where ERA5 performed most poorly. We further interpret our methods using Shapley additive explanations. Our results indicate that data-driven techniques could have an important role in simulating surface radiation fluxes and in improving reanalysis products. Significance Statement Simulating the amount of sunlight reaching Earth’s surface is difficult because it relies on a good understanding of how much clouds absorb and scatter sunlight. Relative to summertime surface observations, the ERA5 reanalysis still overestimates the amount of sunlight entering the Southern Ocean. We taught some models how to predict the amount of sunlight entering the Southern Ocean using 25 years of surface observations and a small set of meteorological variables from ERA5. By bypassing the ERA5’s internal simulation of the absorption and scattering of sunlight, we can drastically reduce biases in the predicted surface shortwave radiation. Large improvements in cold sectors of cyclones and closer to Antarctica were observed in regions where many numerical models struggle to simulate the amount of incoming sunlight correctly.

Measurement report: Understanding the seasonal cycle of Southern Ocean aerosols

Abstract. The remoteness and extreme conditions of the Southern Ocean and Antarctic region have meant that observations in this region are rare, and typically restricted to summertime during research or resupply voyages. Observations of aerosols outside of the summer season are typically limited to long-term stations, such as Kennaook / Cape Grim (KCG; 40.7∘ S, 144.7∘ E), which is situated in the northern latitudes of the Southern Ocean, and Antarctic research stations, such as the Japanese operated Syowa (SYO; 69.0∘ S, 39.6∘ E). Measurements in the midlatitudes of the Southern Ocean are important, particularly in light of recent observations that highlighted the latitudinal gradient that exists across the region in summertime. Here we present 2 years (March 2016–March 2018) of observations from Macquarie Island (MQI; 54.5∘ S, 159.0∘ E) of aerosol (condensation nuclei larger than 10 nm, CN10) and cloud condensation nuclei (CCN at various supersaturations) concentrations. This important multi-year data set is characterised, and its features are compared with the long-term data sets from KCG and SYO together with those from recent, regionally relevant voyages. CN10 concentrations were the highest at KCG by a factor of ∼50 % across all non-winter seasons compared to the other two stations, which were similar (summer medians of 530, 426 and 468 cm−3 at KCG, MQI and SYO, respectively). In wintertime, seasonal minima at KCG and MQI were similar (142 and 152 cm−3, respectively), with SYO being distinctly lower (87 cm−3), likely the result of the reduction in sea spray aerosol generation due to the sea ice ocean cover around the site. CN10 seasonal maxima were observed at the stations at different times of year, with KCG and MQI exhibiting January maxima and SYO having a distinct February high. Comparison of CCN0.5 data between KCG and MQI showed similar overall trends with summertime maxima and wintertime minima; however, KCG exhibited slightly (∼10 %) higher concentrations in summer (medians of 158 and 145 cm−3, respectively), whereas KCG showed ∼40 % lower concentrations than MQI in winter (medians of 57 and 92 cm−3, respectively). Spatial and temporal trends in the data were analysed further by contrasting data to coincident observations that occurred aboard several voyages of the RSV Aurora Australis and the RV Investigator. Results from this study are important for validating and improving our models and highlight the heterogeneity of this pristine region and the need for further long-term observations that capture the seasonal cycles.

CCCXVI. Observationes de lumine Boreali, ab a. MDCCXVI. ad a. MDCCXXXII. partim a se, partim ab aliis, in Svecia habitas

This file is a digitized version of Anders Celsius' 1733 monograph on the aurora borealis, in the form of a PDF with fulltext-search functionality embedded. For a detailed summary of contents, see the Introduction by Per Pippin Aspaas.

Biographical Introduction and Summary of Contents

The fifteenth volume in the series presents a monograph by the famous meteorologist and astronomer Anders (in Latin: Andreas) Celsius (1701–1744), founder of the Centigrade temperature scale known as °C. From a young age, Celsius collected observations of the aurora borealis from Swedish territories. He participated in the editing of the Acta Literaria Sveciæ, the journal of the Royal Swedish Society of Learning and Sciences in Uppsala, in which a substantial number of observations were published. The journal articles in question were often quite short, with the aurora often inserted in lists of meteorological observations with little space for descriptions. By contrast, Celsius’ monograph contains a ten pages long historical intro­duction discussing the periodicity of the phenomenon, arguing that one should differentiate between minor and major aurorae: only the latter were visible on the European Continent and British Isles. There follows a 48-page chronological account of 316 observations made in Sweden, including Finland, during the period from 1716 to 1732. A network of observers established by the Uppsala society provided the basis for this impressive display of Swedish science. Celsius himself had made 67 of the 316 observations; the rest had been reported by sixteen other amateur and professional practitioners of science. The introduction, written by neo-Latinist and historian of science Per Pippin Aspaas, contains biographical information on each of the various observers as well as extracts of Celsius’ text in English translation.

Biographical Introduction, Summary of Contents and Appendix with bibliography of references

The fourteenth volume in the series presents a dissertation by Conradus (Conrad) Quensel (1676–1732), professor at Lund University in Sweden, and his student, Johannes (Hans) Eurodius (1703–1756). In the text, detailed descriptions of two northern lights seen in Lund in the autumn of 1726 are accompanied by ample discussion of observations made ten years earlier in both Sweden and on the Continent, where an exceptionally strong auroral outbreak was seen in March 1716. The theoretical deliberations of Quensel/Eurodius largely follow theories presented by Friedrich Wolff and Johann Friedrich Weidler in the aftermath of the 1716 event. As praeses, Quensel was responsible for the contents, whereas Eurodius acted as respondens, meaning that it was his task to defend the dissertation orally in a public defence. It is unclear who actually wrote the dissertation text. The introduction, written by neo-Latinist and historian of science Per Pippin Aspaas, contains biographical information about the authors as well as a summary with ample extracts of the Latin text in English translation. A list explaining the references in Quensel/Eurodius’ text rounds off the introduction.

Recombination in Polar InGaN/GaN LED Structures with Wide Quantum Wells

The analysis of the photoluminescence of polar light emitting diode (LED) structures with a 25 nm In0.17Ga0.83N quantum well is reported. The observed emission most likely originates from a set of energetically close excited states (ES), while the ground state decays only extremely slowly on a μs‐to‐ms timescale, that is, long‐living charge accumulates there. However, this population can also be quantified spectroscopically by applying short reverse voltage pulses. The emission from ES is effective and nearly exponential with decay time constants of 1.5 and 8 ns at 6 and 300 K, respectively, and is likely dominated by radiative processes. These findings point to a possible route to improved polar device architectures.

Tromsø Study: Northern Lights of Sex-specific Time Trends in Incident Atrial Fibrillation.

We have read the research paper entitled ‘Sex-specific time trends in incident atrial fibrillation and the contribution of risk factors: the Tromsø Study 1994–2016’ by Sharashova E. et al.1 Here, we would like to draw your attention to a few points of the study. In the Tromsø Study, it has been indicated that atrial fibrillation (AF) incidence decreased in women and increased following a reverse U-shape in men between 1994 and 2016. Reduction in blood pressure had the largest contribution to the decrease in AF incidence in women, and increase in body mass index (BMI) had the largest contribution to the increase in AF incidence in men. Body mass index increase in women had almost no effect on the AF incidence trend. On the other hand, increase in BMI in men doubled AF incidence rate and obesity is recognized as an independent risk factor for the incidence and progression of AF. The study named ‘Obesity and the risk of new-onset atrial fibrillation’ revealed that in multivariable models adjusted for cardiovascular risk factors, a 4% increase in AF risk per 1-unit increase in BMI was observed both in men and in women.2 In the study, the maximum difference between the mean BMI in males was 1.2 kg/m2. So, it is doubtful to explain the two-fold increase in AF incidence in males by associating it with increase in BMI alone. The Women’s Health Study, which included 34 309 women, revealed that for each 1 kg/m2 increase in BMI, there is a 4.7% increase in the risk of developing AF.3 However, in the Tromsø Study, BMI increase in women had almost no effect on the AF incidence trend. The fact that the increase in BMI led to different results between male and female groups suggests that other factors may be effective.

Martian Proton Aurora Brightening Reveals Atmospheric Ion Loss Intensifying

AbstractThe Martian proton aurora is a distinct aurora phenomenon resulting from the direct deposition of solar wind energy into Mars' dayside atmosphere. What solar wind parameters influence the aurora activity in the short term is yet unknown, as are the associated repercussions in the Martian atmospheric ion loss. Here we present observational evidence of synchronized proton aurora brightening and atmospheric ion loss intensifying on Mars, controlled by solar wind dynamic pressure, using observations by the Mars Atmosphere and Volatile Evolution spacecraft. The solar wind dynamic pressure possibly has a saturation effect on brightening proton aurora. Significant erosion of the Martian ionosphere during periods of high dynamic pressure indicates at least five‐to‐tenfold increase in atmospheric ion loss. An empirical relationship between ion escape rate and auroral emission enhancement is established, providing a new proxy of Mars' atmospheric ion loss with optical imaging that may be used remotely and with greater flexibility.

Investigation of low-temperature plasmas formed in low-density gases surrounding laser-produced plasmas

Abstract Low-temperature plasma production is possible as a result of photoionization using high-intensity extreme ultraviolet (EUV) and soft X-ray (SXR) pulses. Plasma of this type is also present in outer space, e.g., aurora borealis. It also occurs when high-velocity objects enter the atmosphere, during which period high temperatures can be produced locally by friction. Low-temperature plasma is also formed in an ambient gas surrounding the hot laser-produced plasma (LPP). In this work, a special system has been prepared for investigation of this type of plasma. The LPP was created inside a chamber filled with a gas under a low pressure, of the order of 1–50 mbar, by a laser pulse (3–9 J, 1–8 ns) focused onto a gas puff target. In such a case, the SXR/EUV radiation emitted from the LPP was partially absorbed in the low-density gas. In this case, high- and low-temperature plasmas (T e ~100 eV and ~1 eV, respectively) were created locally in the chamber. Investigation of the EUV-induced plasmas was performed mainly using spectral methods in ultraviolet/visible (UV/VIS) light. The measurements were performed using an echelle spectrometer, and additionally, spatial–temporal measurements were performed using an optical streak camera. Spectral analysis was supported by the PGOPHER numerical code.