scholarly journals Intercomparison of Assimilated Coastal Wave Data in the Northwestern Pacific Area

2020 ◽  
Vol 8 (8) ◽  
pp. 579 ◽  
Author(s):  
Yukiharu Hisaki

The assimilated coastal wave data are useful for wave climate study, coastal engineering, and design for marine disaster protection. However, the assimilated coastal wave data are few. Here, wave analysis data produced by the JMA (Japan Meteorological Agency) and ERA5 wave data were compared with GPS (Global Positioning System) buoy-measured wave data. In addition, the accuracy of ERA5 wave data for various conditions was investigated. The accuracy of JMA analysis wave height was better than that of ERA5 wave height. The ERA5 wave height was underestimated as the wave height increased. The accuracy of the ERA5 wave height was significantly different in fetch-unlimited and fetch-limited conditions. The difference of the skill metrics between fetch-unlimited and fetch-limited conditions was due to the overestimation of the fetch in the ERA5 grid. This result also applied to the wave period.

2020 ◽  
Author(s):  
Hongbin Wang ◽  
Zhiwei Zhang ◽  
Duanyang Liu

<p>Himawari-8 is the new geostationary satellite of the Japan Meteorological Agency (JMA) and carries the Advanced Himawari Imager (AHI), which is greatly improved over past imagers in terms of its number of bands and its temporal/spatial resolution. In this work, two different methods for the detection of the different levels of fog involving heavy pollutants by using the Himawari-8 were developed in China. The two different methods are the method of the difference between the 11.2 mm and 3.9 mm brightness temperatures (BTD<sub>3.9-11.2</sub>) and the method of 3.9 mm Pseudo-Emissivity (ems<sub>3.9</sub>).  The 3.9 mm Pseudo-Emissivity is the ratio of the observed 3.9 mm radiance and the 3.9 mm blackbody radiance calculated using the 11.2 mm brightness temperature. We identified the parameters optimal threshold at the 2400 stations and the grid points using the BTD<sub>3.9-11.2</sub> and ems<sub>3.9</sub> for different levels of fog involving heavy pollutants. Results on land and sea from the two methods were compared with surface observations from 2400 weather stations in China and CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) VFM (Vertical Feature Mask) products. The results show that both the method of BTD<sub>3.9-11.2</sub> and the method of ems<sub>3.9</sub> can accurately identify the different levels of fog involving heavy pollutants and the accuracy of ems<sub>3.9 </sub>method is slightly better than the BTD<sub>3.9-11.2</sub>. The accuracy of two methods has increased significantly and the false alarm rate has significantly decreased with the decrease of the visibility. When the visibility is less than 50 m, the HR, FAR and KSS of the BTD<sub>3.9-11.2</sub> method (the ems<sub>3.9 </sub>method) were 0.89 (0.90), 0.15 (0.15) and 0.74 (0.75), respectively. When mid- or high-level clouds were removed using surface temperature of the ground observations, the HR and KSS of two methods for the different levels of fog has increased significantly, and the FAR has significantly decreased. When the visibility is less than 1000 m, the HR of the BTD<sub>3.9-11.2</sub> method (the ems<sub>3.9 </sub>method) is increased to 0.81(0.85) from 0.71 (0.74), the FAR is decreased to 0.12 (0.13) from 0.27 (0.28), and the KSS is increased to 0.69 (0.72) from 0.44 (0.46). The KSS of two method increase by 0.23 and 0.26, respectively. Three cases analysis show that the fog area can be clearly identified by using the BTD<sub>3.9-11.2</sub>, ems<sub>3.9</sub> and RGB composite image. The results of the detection of sea fog by using Himawari-8 data and using CALIPSO VFM products have consistency.</p>


2015 ◽  
Vol 32 (6) ◽  
pp. 1257-1269 ◽  
Author(s):  
V. Sanil Kumar ◽  
T. Muhammed Naseef

AbstractBulk wave parameters, such as wave height and wave period, are required for engineering and environmental applications. In this study, measured wave data from six shallow-water locations in the data-sparse north Indian Ocean are used to assess the Interim European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis [ERA-Interim (ERA-I)] wave height and period data in the nearshore waters around India. The difference between the ERA-I significant wave height (SWH) and the buoy SWH varies from −1 to 1 m with an average value of −0.1 m for the three west coast locations. For the three east coast locations, the variation ranges from −2.2 to 1.7 m with an average value of −0.2 m. The ERA-I SWH data show positive biases, indicating an overall overestimation for all locations except for the northern location in the west coast of India, where underestimation is observed. During the tropical cyclone period, a large (~33%) underestimation of SWH in the ERA-I data is observed. Hence, the ERA-I SWH data cannot be used for design applications without site-specific validation. The difference between the wave period from ERA-I and the energy wave period from the buoy varies from −6 to 4 s with an average value of −0.3 s. The intercomparisons suggest that the ERA-I dataset shows encouraging agreement with the annual mean SWH and the energy wave period.


1986 ◽  
Vol 1 (20) ◽  
pp. 4 ◽  
Author(s):  
Richard Burrows ◽  
Barham A. Salih

The paper discusses the long-term statistical properties of ocean and coastal wave climates derived from the analysis of instrumental wave data. The aim of the work reported has been to determine the theoretical distributions, from those commonly used in analysis of wave data, which best describe the joint probability of significant wave height, Hs, and mean zero-upcrossing period, Tz. A method of modelling the wave climate in this manner has been developed utilizing parametric means of specification. The data base used in the study covers records from 18 sites around the British Isles.


Sensors ◽  
2019 ◽  
Vol 19 (13) ◽  
pp. 2914 ◽  
Author(s):  
Jungang Yang ◽  
Jie Zhang

The validation of significant wave height (SWH) data measured by the Sentinel-3A/3B SAR Altimeter (SRAL) is essential for the application of the data in ocean wave monitoring, forecasting and wave climate studies. Sentinel-3A/3B SWH data are validated by comparisons with U. S. National Data Buoy Center (NDBC) buoys, using a spatial scale of 25 km and a temporal scale of 30 min, and with Jason-3 data at their crossovers, using a time difference of less than 30 min. The comparisons with NDBC buoy data show that the root-mean-square error (RMSE) of Sentinel-3A SWH is 0.30 m, and that of Sentinel-3B is no more than 0.31 m. The pseudo-Low-Resolution Mode (PLRM) SWH is slightly better than that of the Synthetic Aperture Radar (SAR) mode. The statistical analysis of Sentinel-3A/3B SWH in the bin of 0.5 m wave height shows that the accuracy of Sentinel-3A/3B SWH data decreases with increasing wave height. The analysis of the monthly biases and RMSEs of Sentinel-3A SWH shows that Sentinel-3A SWH are stable and have a slight upward trend with time. The comparisons with Jason-3 data show that SWH of Sentinel-3A and Jason-3 are consistent in the global ocean. Finally, the piecewise calibration functions are given for the calibration of Sentinel-3A/3B SWH. The results of the study show that Sentinel-3A/3B SWH data have high accuracy and remain stable.


2017 ◽  
Vol 862 ◽  
pp. 67-71
Author(s):  
Muhammad Zikra ◽  
Noriaki Hashimoto ◽  
Kodama Mitsuyasu ◽  
Trika Pitana ◽  
Silvianita

The global ocean wave climate has long been of interest to the ocean engineering community because of the need for accurate operational wave data for applications such as vessel design, design of offshore and coastal structures or naval operations. Recently, there has been a major interest in wave climate changes as a result of global warming. Therefore, studies on predicting the effect of global warming on ocean wave climate are required. The objectives of this study are to analyze the accuracy and variability of global significant wave height hindcast for the 25 year period 1979-2003. This study describes the 25 year global significant wave height simulation derived from the Japan Meteorology Agency/Meteorology Research Institute (JMA/MRI)-AGCM3.2 wind climate data. The wind climate data were input into ocean wave model WAM with a global grid of spacing 1o in latitude by 1o in longitude. In situ wind and wave data sets from National Data Buoy Center (NDBC)-National Oceanic and Atmospheric Administration (NOAA) database were used to evaluate the hindcast accuracy. The validation showed good agreement both wind and waves data. The wave hindcast analysis show that the seasonal variability of significant wave height in the Northern Hemisphere is greater than in the Southern Hemisphere. Meanwhile, most of the equatorial regions are in calm condition all year.


Author(s):  
John P. Langmore ◽  
Brian D. Athey

Although electron diffraction indicates better than 0.3nm preservation of biological structure in vitreous ice, the imaging of molecules in ice is limited by low contrast. Thus, low-dose images of frozen-hydrated molecules have significantly more noise than images of air-dried or negatively-stained molecules. We have addressed the question of the origins of this loss of contrast. One unavoidable effect is the reduction in scattering contrast between a molecule and the background. In effect, the difference in scattering power between a molecule and its background is 2-5 times less in a layer of ice than in vacuum or negative stain. A second, previously unrecognized, effect is the large, incoherent background of inelastic scattering from the ice. This background reduces both scattering and phase contrast by an additional factor of about 3, as shown in this paper. We have used energy filtration on the Zeiss EM902 in order to eliminate this second effect, and also increase scattering contrast in bright-field and dark-field.


2018 ◽  
Vol 2 (5) ◽  
pp. 744
Author(s):  
Zainur Zainur

This research was motivated by the low learning outcomes of grade IX SMP Muhammadiyah Padang LuasKecamatan Tambang Kabupaten Kampar. This study aims to improve learning outcomes in mathematicslearning through STAD type cooperative learning with the RME approach in class IX SMP MuhammadiyahPadang Luas Kecamatan Tambang Kabupaten Kampar. The subjects of this study were all classes IX in SMPMuhammadiyah Padang Luas Kecamatan Tambang Kabupaten Kampar totaling 26 people. The form ofresearch is classroom action research. This research instrument consists of performance instruments and datacollection instruments in the form of teacher activity observation sheets and activities. The results of the studystated that there were significant differences between students' mathematics learning outcomes before applyingthe STAD type cooperative learning model with the RME approach with after applying the STAD typecooperative learning model with the RME approach. The difference shows student learning outcomes after theaction is better than before the action with completeness reaching 80.77% or 21 completed. Based on the resultsof the study and discussion it can be concluded that the application of STAD type learning model with RealisticMathematic Education (RME) approach can improve the learning outcomes of grade IX students of SMPMuhammadiyah Padang Luas Kecamatan Tambang Kabupaten Kampar on statistical material.


Jurnal KATA ◽  
2018 ◽  
Vol 2 (1) ◽  
pp. 50
Author(s):  
Krisna Aji Kusuma ◽  
Herman J Waluyo ◽  
Nugraheni Eko Wardani

<p><em>This study aims to describe the intertextuality relationship between the novel Pasung Jiwa by Okky Madasari and Calabai by Pepi Al-Bayqunie. The type of research is descriptive qualitative approach using content analysis. Data are collected by inventorying events that are similarities and differences, specifications on the characters, settings, plots, and themes of both text. The research results indicate that there are similar themes on the two novels, the theme of self actualization in addition with the theme of family and friendship. The same characterization are also used by both author, masculine figures with feminine soul characters. The difference between the two novels lies on the plot and setting. Pasung Jiwa uses progressive plot and Calabai uses a flash-back plot.. Okky Madasari takes Java Island as the background in the novel Pasung Jiwa, while the novel Calabai, Pepi Al-Bayqunie using the setting of Sulawesi Island. The basis of the similarity of theme and characterization supported by the similirity of events in the story shows the existence of intertextual relationship between the two novels. As a previously published work, the novel Pasung Jiwa by Okky Madasari is a hipogram and novel Calabai by Pepi A-Bayqunie as a transformational text. On the theme and characterization, the transformation of Calabai forward the hypogram, while in the plot and setting deviates his hypogram, Pasung Jiwa.</em></p><p>Penelitian ini bertujuan untuk mendeskripsikan hubungan intertekstualitas antara novel Pasung Jiwa karya Okky Madasari dan novel Calabai karya Pepi Al-Bayqunie. Jenis penelitian ini adalah deskriptif kualitatif dengan pendekatan konten analisis. Data dikumpulkan dengan menginventariskan peristiwa yang merupakan persamaan dan perbedaan, spesifikasi pada tokoh, latar, alur, dan tema dari kedua teks. Hasil penelitian ini menunjukkan bahwa terdapat kesamaan tema pada kedua novel, yaitu tema aktualisasi diri, ditambah dengan tema keluarga dan persahabatan. Penokohan yang sama juga digunakan oleh kedua penulis, yaitu tokoh maskulin dengan karakter jiwa feminin. Perbedaan kedua novel terletak pada alur dan latar. Pasung Jiwa menggunakan alur maju dan Calabai menggunakan alur campuran. Latar dalam novel Pasung Jiwa, Okky Madasari mengambil latar Pulau Jawa, sedangkan novel Calabai, Pepi Al-Bayqunie menggunakan latar Pulau Sulawesi. Dasar kesamaan tema dan penokohan didukung kesamaan peristiwa-peristiwa dalam cerita menunjukkan adanya hubungan intertekstual antara kedua novel. Sebagai karya yang terbit terlebih dahulu menjadikan novel Pasung Jiwa karya Okky Madasari adalah hipogram dan novel Calabai karya Pepi Al-Bayqunie sebagai teks transformasi. Pada tema dan penokohan, transformasi Calabai meneruskan hipogram, sedangkan pada alur dan latar menyimpangi hipogramnya, Pasung Jiwa.</p>


Author(s):  
Danila Azzolina ◽  
Giulia Lorenzoni ◽  
Luciano Silvestri ◽  
Ilaria Prosepe ◽  
Paola Berchialla ◽  
...  

Abstract Objective The COVID-19 outbreak started in Italy on February 20th, 2020, and has resulted in many deaths and intensive care unit (ICU) admissions. This study aimed to illustrate the epidemic COVID-19 growth pattern in Italy by considering the regional differences in disease diffusion during the first three months of the epidemic. Study design and methods Official COVID-19 data were obtained from the Italian Civil Protection Department of the Council of Ministers Presidency. The mortality and ICU admission rates per 100 000 inhabitants were calculated at the regional level and summarized via a Bayesian multilevel meta-analysis. Data were retrieved until April 21st, 2020. Results The highest cumulative mortality rates per 100 000 inhabitants were observed in northern Italy, particularly in Lombardia (85.3, 95% credibility intervals [CI] 75.7–94.7). The difference in the mortality rates between northern and southern Italy increased over time, reaching a difference of 67.72 (95% CI = 66–67) cases on April 2nd. Conclusions Northern Italy showed higher and increasing mortality rates during the first three months of the epidemic. The uncontrolled virus circulation preceding the infection spreading in southern Italy had a considerable impact on system burnout. This experience demonstrates that preparedness against the pandemic is of crucial importance to contain its disruptive effects.


2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
R Bosco ◽  
S Gambelli ◽  
V Urbano ◽  
G Cevenini ◽  
G Messina

Abstract Background Sanitizing the operating theatres (OT) is important to minimize risk of post-operative infections. Disinfection procedures between one operation and another is less aggressive than final cleaning procedures, at the end of the day. Aim was assessing the difference of contamination: i) between different levels of disinfection; ii) before and after the use of a UVC Device (UVC-D). Methods Between December 2019/February 2020 a cross sectional study was conducted in OT in a real clinical context. 94 Petri dishes (PD) were used in 3 OT. Three different sanitation levels (SL1-3) were compared pre- and post-use of UVC-D: i) No cleaning after surgery (SL1); ii) after in-between cleaning (SL2); iii) after terminal cleaning (SL3). UVC-D was employed for 6 minutes, 3 minutes per bed side. PD were incubated at 36 °C and colony forming unit (CFU) counted at 48h. Descriptive statistic, Wilcoxon and Mann-Whitney tests were performed to assess the contamination levels in total, pre/post use of UVC-D, and between different sanitation levels, respectively. Results In total we had a mean of 3.39 CFU/PD (C.I. 2.05 - 4.74) and a median of 1 CFU/PD (Min. 0 - Max. 39), after UVC-D use we had a mean of 2.20 CFU/PD (C.I. 0.69 - 5.09) and a median of 0 CFU/PD (Min. 0 - Max. 133). The UVC-D led to a significant reduction of CFU (p &lt; 0.001). Without UVC-D we had a significant CFU drop (p &lt; 0.05) between SL1 and SL3. Using UVC-D, we observed significant reductions of contamination (p &lt; 0.05) between SL3 and SL1. Comparing SL1 (median 0) post UVC-D use vs SL2 pre UVC-D use (median 0.5), and SL2 post UVC-D use (median 0) vs SL3 pre UVC-D use (median 1) we had a significant reduction of contamination (p &lt; 0.05). Conclusions UVC-D improved environmental contamination in any of the three sanitation levels. Furthermore, the use of UVC-D alone was better than in-between and terminal cleaning. Although these encouraging results, the cleaning procedures executed by dedicated staff has to be considered. Key messages UVC are efficient to decrease contamination in operating theatres regardless of sanitation levels. The additional use of UVC technology to standard cleaning procedures significantly improves sanitation levels.


Sign in / Sign up

Export Citation Format

Share Document