scholarly journals SOME FEATURES OF OCEANOLOGICAL CONDITIONS OF THE MICROALGAE AUTUMN-FLOWERING NEAR THE SOUTHEAST SHORE OF KAMCHATKA

2020 ◽  
pp. 70-73
Author(s):  
М.К. Пичугин ◽  
И.А. Гурвич ◽  
Е.С. Хазанова ◽  
П.А. Салюк
Keyword(s):  
Sea Surface ◽  
Optical Observations ◽  
Observation System ◽  
Positive Anomaly ◽  
Composite Image ◽  
The Past ◽  
Current Trends ◽  
Autumn Flowering ◽  
Dark Green ◽  
Sentinel 2

В этой работе продемонстрированы возможности оптических наблюдений со спутников Sentinel-2, 3 для изучения связанных физических и биологических процессов в поверхностном слое океане во время интенсивного осеннего цветения фитопланктона у юго-восточного побережья Камчатки в сентябре 2020 г. В Авачинском заливе цветение водорослей проявлялось в виде областей с высокой концентрацией хлорофилла-а, придавая морской поверхности соответствующий темно-зеленый оттенок. На композитном изображении с разрешением 10 м из-за выраженных спектральных различий на морской поверхности выделялись скопления водорослей, организованные в сложные системы мезомасштабных и субмезомасштабных взаимодействующих вихревых структур. По данным реанализа ERA5 установлено, что среднемесячная температура поверхности океана (ТПО) акватории Авачинского залива в сентябре 2020 г. показала положительную аномалию с максимумом ТПО (12.0°С) за последние 42 года при климатической норме 10.4°С. Мы допускаем, что при сохранении тенденции роста в ближайшие годы этот максимум будет превышен. The paper demonstrates the possibilities of optical observations from the satellites Sentinel-2, 3 for studying linked physical and biological processes in the ocean's surface layer. The specific example of using an observation system for surveillance over intense autumn-flowering of phytoplankton near Kamchatka's southeast shore in September 2020 is considered. In Avachinsky Bay, the microalgae flowering manifested as areas with high chlorophyll-a concentration, coloring the sea surface into the corresponding dark green shade. On a composite image with a resolution of 10 m, significant spectral differences on the sea surface highlighted conglomerates of algae organized in complex systems of mesoscale and submesoscale interacting vortex structures. According to ERA5 reanalysis, it was found that the average monthly sea-surface temperature in Avachinsky Bay in September 2020 demonstrated a positive anomaly with a maximum (12,0° C) over the past 42 years with a climate normal of 10,4° C. It is assumed that this maximum will be surpassed if the current trends continue.

scholarly journals Mapping South Baltic Near-Shore Bathymetry Using Sentinel-2 Observations

2017 ◽  
Vol 24 (3) ◽  
pp. 15-25 ◽  
Author(s):  
Andrzej Chybicki
Keyword(s):  
European Space Agency ◽  
Satellite Observation ◽  
Optical Observations ◽  
Observation System ◽  
The South ◽  
Single Beam ◽  
Satellite Systems ◽  
In Situ Data ◽  
Near Shore ◽  
Sentinel 2

Abstract One of the most promising new applications of remote observation satellite systems (RO) is the near-shore bathymetry estimation based on spaceborn multispectral imageries. In recent years, many experiments aiming to estimate bathymetry in optically shallow water with the use of remote optical observations have been presented. In this paper, optimal models of satellite derived bathymetry (SDB) for relatively turbid waters of the South Baltic Sea were presented. The obtained results were analysed in terms of depth error estimation, spatial distribution, and overall quality. The models were calibrated based on sounding (in-situ) data obtained by a single-beam echo sounder, which was retrieved from the Maritime Office in Gdynia, Poland. The remote observations for this study were delivered by the recently deployed European Space Agency Sentinel-2 satellite observation system. A detailed analysis of the obtained results has shown that the tested methods can be successfully applied for the South Baltic region at depths of 12-18 meters. However, significant limitations were observed. The performed experiments have revealed that the error of model calibration, expressed in meters (RMSE), equals up to 10-20% of the real depth and is, generally, case dependent. To overcome this drawback, a novel indicator of determining the maximal SDB depth was proposed. What is important, the proposed SDB quality indicator is derived only on the basis of remotely registered data and therefore can be applied operationally.

scholarly journals Cloud Cover throughout All the Paddy Rice Fields in Guangdong, China: Impacts on Sentinel 2 MSI and Landsat 8 OLI Optical Observations

2021 ◽  
Vol 13 (15) ◽  
pp. 2961
Author(s):  
Rui Jiang ◽  
Arturo Sanchez-Azofeifa ◽  
Kati Laakso ◽  
Yan Xu ◽  
Zhiyan Zhou ◽  
...  
Keyword(s):  
Cloud Cover ◽  
Southern China ◽  
Vegetation Indices ◽  
Paddy Rice ◽  
Rice Fields ◽  
Optical Observations ◽  
Landsat 8 ◽  
Monthly Basis ◽  
Satellite Sensors ◽  
Sentinel 2

Cloud cover hinders the effective use of vegetation indices from optical satellite-acquired imagery in cloudy agricultural production areas, such as Guangdong, a subtropical province in southern China which supports two-season rice production. The number of cloud-free observations for the earth-orbiting optical satellite sensors must be determined to verify how much their observations are affected by clouds. This study determines the quantified wide-ranging impact of clouds on optical satellite observations by mapping the annual total observations (ATOs), annual cloud-free observations (ACFOs), monthly cloud-free observations (MCFOs) maps, and acquisition probability (AP) of ACFOs for the Sentinel 2 (2017–2019) and Landsat 8 (2014–2019) for all the paddy rice fields in Guangdong province (APRFG), China. The ATOs of Landsat 8 showed relatively stable observations compared to the Sentinel 2, and the per-field ACFOs of Sentinel 2 and Landsat 8 were unevenly distributed. The MCFOs varied on a monthly basis, but in general, the MCFOs were greater between August and December than between January and July. Additionally, the AP of usable ACFOs with 52.1% (Landsat 8) and 47.7% (Sentinel 2) indicated that these two satellite sensors provided markedly restricted observation capability for rice in the study area. Our findings are particularly important and useful in the tropics and subtropics, and the analysis has described cloud cover frequency and pervasiveness throughout different portions of the rice growing season, providing insight into how rice monitoring activities by using Sentinel 2 and Landsat 8 imagery in Guangdong would be impacted by cloud cover.

“Economics in Command?” Ideology and Policy Since the Third Plenum, 1978–1984

1984 ◽  
Vol 99 ◽  
pp. 417-461 ◽  
Author(s):  
Stuart R. Schram
Keyword(s):  
Policy Making ◽  
Question Mark ◽  
The Third ◽  
The Past ◽  
Great Leap ◽  
Current Trends

In this article, I shall attempt to give an overview of the most important political and ideological developments during the past six years, and in this context, to assess current trends in China. The three-word title is, of course, deliberately modelled on the Great Leap slogan “Politics in command”, and is intended to evoke the problem of whether or not policy-making since 1978 has been largely shaged by economic realities, and/or by the economic goals of the, leadership I have placed a question mark after it because, though I shall certainly express some opinions on this topic before I have done, I doubt that the issue can as yet be regarded as finally settled.

Composite image of chlorophyll and sea surface temperature (SST) using MODIS-AQUA

2005 ◽  
Vol 33 (2) ◽  
pp. 177-180
Author(s):  
Prakash Chauhan ◽  
P. V. Nagamani ◽  
H. U. Solanki ◽  
Shailesh Nayak
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Sea Surface ◽  
Composite Image

scholarly journals Current Trends in Dental Composites

1995 ◽  
Vol 6 (4) ◽  
pp. 302-318 ◽  
Author(s):  
J.L. Ferracane
Keyword(s):  
Wear Resistance ◽  
Clinical Performance ◽  
Color Stability ◽  
Dental Composites ◽  
Filler Materials ◽  
Posterior Teeth ◽  
The Past ◽  
Current Trends ◽  
Dentin Adhesives ◽  
High Concentrations

The clinical performance of dental composites has been significantly improved over the past decade through modifications in formulation that include: using more stable polymerization promoters for greater color stability; incorporating high concentrations of finely ground fillers to produce adequate strength and excellent wear resistance while retaining translucency ; adding radiopacifying agents for improved diagnostics; and utilizing dentin adhesives. However, there are problems which limit the use of composites, especially in posterior teeth. The materials remain very technique-sensitive, due to the extensive contraction which accompanies polymerization and negatively influences marginal sealing. In addition, the materials are generally considered to have inadequate mechanical properties and wear resistance in contact areas to serve as total replacements for amalgams. Current efforts are focusing on several areas, including the development of non- or minimally-shrinking dental composites containing spiro-orthocarbonates as additives to dimethacrylates or epoxy-base resins, and the production of alternative filler materials for ideal wear resistance and esthetics. This paper reviews the composition and characteristics of current dental composites, as well as recent areas of study.

scholarly journals Remote Sensing of Sea Surface Artificial Floating Plastic Targets with Sentinel-2 and Unmanned Aerial Systems (Plastic Litter Project 2019)

2020 ◽  
Vol 12 (12) ◽  
pp. 2013
Author(s):  
Konstantinos Topouzelis ◽  
Dimitris Papageorgiou ◽  
Alexandros Karagaitanakis ◽  
Apostolos Papakonstantinou ◽  
Manuel Arias Ballesteros
Keyword(s):  
Remote Sensing ◽  
Large Scale ◽  
Field Experiments ◽  
Spectral Unmixing ◽  
Sea Surface ◽  
Spectral Signature ◽  
Unmanned Aerial Systems ◽  
Real Environment ◽  
Promising Tool ◽  
Sentinel 2

Remote sensing is a promising tool for the detection of floating marine plastics offering extensive area coverage and frequent observations. While floating plastics are reported in high concentrations in many places around the globe, no referencing dataset exists either for understanding the spectral behavior of floating plastics in a real environment, or for calibrating remote sensing algorithms and validating their results. To tackle this problem, we initiated the Plastic Litter Projects (PLPs), where large artificial plastic targets were constructed and deployed on the sea surface. The first such experiment was realised in the summer of 2018 (PLP2018) with three large targets of 10 × 10 m. Hereafter, we present the second Plastic Litter Project (PLP2019), where smaller 5 × 5 m targets were constructed to better simulate near-real conditions and examine the limitations of the detection with Sentinel-2 images. The smaller targets and the multiple acquisition dates allowed for several observations, with the targets being connected in a modular way to create different configurations of various sizes, material composition and coverage. A spectral signature for the PET (polyethylene terephthalate) targets was produced through modifying the U.S. Geological Survey PET signature using an inverse spectral unmixing calculation, and the resulting signature was used to perform a matched filtering processing on the Sentinel-2 images. The results provide evidence that under suitable conditions, pixels with a PET abundance fraction of at least as low as 25% can be successfully detected, while pinpointing several factors that significantly impact the detection capabilities. To the best of our knowledge, the 2018 and 2019 Plastic Litter Projects are to date the only large-scale field experiments on the remote detection of floating marine litter in a near-real environment and can be used as a reference for more extensive validation/calibration campaigns.

scholarly journals Fluorescent Chemosensors for Ion and Molecule Recognition: The Next Chapter

2021 ◽  
Vol 2 ◽  
Author(s):  
Kai-Cheng Yan ◽  
Axel Steinbrueck ◽  
Adam C. Sedgwick ◽  
Tony D. James
Keyword(s):  
State Of The Art ◽  
Fluorescent Chemosensors ◽  
Distant Future ◽  
The Past ◽  
Current Trends ◽  
Current State ◽  
Future Challenges ◽  
Molecule Recognition

Over the past 30 years fluorescent chemosensors have evolved to incorporate many optical-based modalities and strategies. In this perspective we seek to highlight the current state of the art as well as provide our viewpoint on the most significant future challenges remaining in the area. To underscore current trends in the field and to facilitate understanding of the area, we provide the reader with appropriate contemporary examples. We then conclude with our thoughts on the most probable directions that chemosensor development will take in the not-too-distant future.

scholarly journals Military museums in Poland – between the past and the future

2020 ◽  
Vol 8 (3) ◽  
pp. 5-39
Author(s):  
Dagmara Chylińska ◽  
Łukasz Musiaka
Keyword(s):  
Collective Memory ◽  
Subject Matter ◽  
Cultural Tourism ◽  
The Past ◽  
Current Trends ◽  
The World ◽  
The Subject ◽  
Museum Practice ◽  
Further Development ◽  
Special Mirror

Museums are a constantly developing segment of cultural tourism. Poland is in line with current trends in museums, expanding its offer and adapting it to the requirements of the world of contemporary image culture and multisensory experiences, which is increasingly dominated by technology. The authors of the paper undertook to recognise the specificity of military museums, by conducting a survey of approximately a third of all such institutions in Poland. Due to the subject-matter of their exhibitions, military museums create a broad field of research both in terms of aesthetics and museum practice, as well as the issues of shaping and maintaining collective memory and the identity of the nation. They form a special mirror in which the country’s ideas and aspirations are reflected more often than any real characteristics. In reference to contemporary trends in museums, the article aims to place Polish military museums between locality and universality, education and entertainment, stability and dynamism, knowledge and experience. The results obtained allowed the authors to distinguish three groups of military museums in Poland, as well as indicate conditions conducive to the further development of such attractions in the country.

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