Article
Environmental Sciences
Bruna Monallize Duarte Moura Guimaraes, Iran Eduardo Lima Neto
Summary: The study aimed to determine spatiotemporal variations in chlorophyll-a (Chl-a) concentration using hydroclimatic and nutrient variables in tropical reservoirs in Brazil. A model for Chl-a prediction was proposed based on the product of nitrogen, phosphorus, volume, and precipitation. The results showed that nutrients had a better predictability for Chl-a than hydroclimatic variables. Chl-a blooms were more frequent in periods of high precipitation and low volume, and their response to the parameters varied.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2023)
Article
Biodiversity Conservation
C. E. Binding, L. Pizzolato, C. Zeng
Summary: Early detection and comprehensive monitoring of inland water algal blooms are crucial for effective management and mitigation of potential impacts. Satellite Earth Observation technology has greatly enhanced algal bloom monitoring capabilities. Studies on three Canadian lakes have shown widespread blooms with varying intensity and duration, emphasizing the importance of utilizing multiple bloom indices for accurate assessment.
ECOLOGICAL INDICATORS
(2021)
Review
Environmental Sciences
Rabia Munsaf Khan, Bahram Salehi, Masoud Mahdianpari, Fariba Mohammadimanesh, Giorgos Mountrakis, Lindi J. Quackenbush
Summary: This study analyzed a large number of journal articles to explore spatiotemporal trends in harmful algal bloom (HAB) monitoring, identified research gaps and future directions, and suggested the need for standardized reporting methods and potential technological advancements and data fusion for HAB detection and monitoring.
Article
Environmental Sciences
Xiao Sun, Yunlin Zhang, Kun Shi, Yibo Zhang, Na Li, Weijia Wang, Xin Huang, Boqiang Qin
Summary: Proximal remote sensing combined with machine learning algorithms showed great potential in monitoring water quality in inland waters with high accuracy. Developed and validated models led to effective and continuous monitoring of various water bodies.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Review
Environmental Sciences
Farzane Mohseni, Fatemeh Saba, S. Mohammad Mirmazloumi, Meisam Amani, Mehdi Mokhtarzade, Sadegh Jamali, Sahel Mahdavi
Summary: This paper reviews the application of remote sensing techniques in ocean water quality (OWQ) monitoring, introducing common OWQ parameters and monitoring techniques. The study finds that chlorophyll-a and colored dissolved organic matter are the dominant parameters for OWQ monitoring, and data from optical and passive microwave sensors are effective in estimating OWQ parameters.
MARINE ENVIRONMENTAL RESEARCH
(2022)
Article
Engineering, Electrical & Electronic
Yue Ma, Kaishan Song, Zhidan Wen, Ge Liu, Yingxin Shang, Lili Lyu, Jia Du, Qian Yang, Sijia Li, Hui Tao, Junbin Hou
Summary: This study aimed to find an optimal regression model to predict water turbidity accurately using remote sensing data, identifying gradient boosting decision tree as the best choice. Feature selection technique improved model performance, with B2, B3, B4, and B5 identified as important variables.
IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING
(2021)
Article
Environmental Sciences
Malgorzata Godlewska, Helge Balk, Katarzyna Izydorczyk, Zbigniew Kaczkowski, Joanna Mankiewicz-Boczek, Shaowen Ye
Summary: Cyanobacterial blooms are increasing globally due to eutrophication and climate change. However, there is a lack of high-resolution data for the spatial structure and dynamics of these blooms in real time. In this study, a high-frequency fishery echosounder was used to detect and estimate the distribution and biomass of Microcystis blooms in a shallow lake. The acoustic estimates were compared with fluorometric measurements and chlorophyll a concentrations, showing significant positive correlations. Traditional point samples did not agree as well with the acoustic estimates, particularly in vertical measurements.
SCIENCE OF THE TOTAL ENVIRONMENT
(2023)
Article
Engineering, Environmental
Gizem Tuna Tuygun, Serra Salgut, Alper Elci
Summary: This study applies remote sensing to monitor long-term chlorophyll-a (Chl-a) concentrations and the trophic state index (TSI) in Lake Burdur, Turkey. Surface reflectances from Landsat satellite images are analyzed to estimate a 38-year time series of Chl-a concentrations. The results show variations in Chl-a concentrations over time, with higher concentrations in 2010 and 2021 and lower concentrations between 1991 and 1993. The TSI values suggest Lake Burdur has been mostly hypertrophic throughout the study period.
WATER SCIENCE AND TECHNOLOGY
(2023)
Article
Green & Sustainable Science & Technology
Shengyuan Zhu, Yinglei Wu, Xiaoshuang Ma
Summary: This paper proposes a dual U-Net model based on remote sensing images, which achieves rapid and accurate identification of algal blooms by analyzing the features of algae in different seasons. Experimental results show that the proposed model has an interpretation accuracy of over 90% in most cases and a processing time of less than 10 seconds, outperforming traditional supervised classification methods and single U-Net models trained with data of the entire year.
Article
Remote Sensing
Menghua Wang, Lide Jiang, Karlis Mikelsons, Xiaoming Liu
Summary: This study presents the production of the first-ever near-real-time global daily chlorophyll-a anomaly products, which can detect and identify algae blooms using satellite ocean color measurements. The anomalies represent abnormal chlorophyll-a conditions in global oceans and coastal areas and can be used for various applications, with detailed algorithms and global data processing procedures provided. Several examples demonstrate the detection of algae blooms, including harmful algal blooms, and quantitative evaluations of chlorophyll-a anomalies over global oceans and coastal/inland waters are discussed.
INTERNATIONAL JOURNAL OF APPLIED EARTH OBSERVATION AND GEOINFORMATION
(2021)
Review
Environmental Sciences
Chunyan Cheng, Fei Zhang, Jingchao Shi, Hsiang-Te Kung
Summary: Good surface water quality is crucial for human health and ecology, and land use plays a significant role in its degradation. Agricultural and construction land use negatively impact surface water quality, while woodland use has a positive effect. Statistical methods such as correlation analysis and regression analysis are commonly used in related research, and remote sensing monitoring technology has become an effective tool for comprehensive water quality assessment and management. However, the increase in spatial resolution of remote sensing data presents challenges in data interpretation.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2022)
Review
Environmental Sciences
Yuanrui Li, Qichao Zhou, Yun Zhang, Jingyi Li, Kun Shi
Summary: This study comprehensively reviewed the research trends in remote sensing of phytoplankton blooms through bibliometrics, revealing a substantial increase in research on the use of remote-sensing technology in this field over the past 30 years. Oceanography, Environmental Sciences, and Remote Sensing were the most popular subject categories, with the Chinese Academy of Sciences publishing the largest number of papers. Researchers are increasingly focusing on the phenological response of phytoplankton under climate change conditions and the application of new remote-sensing methods.
Article
Environmental Sciences
Huan Zhao, Junsheng Li, Xiang Yan, Shengzhong Fang, Yichen Du, Bin Xue, Kai Yu, Chen Wang
Summary: The study demonstrates that ground-based imaging remote sensing is an effective method for dynamically monitoring cyanobacterial blooms, accurately reflecting their spatiotemporal distribution characteristics. This method can provide timely and accurate data for salvage treatment and early warnings of cyanobacterial blooms.
Article
Engineering, Environmental
Shunsuke Watanabe, Naoki Matsunami, Ikki Okuma, Podiapen Tannen Naythen, Megumu Fujibayashi, Yasushi Iseri, Aimin Hao, Takahiro Kuba
Summary: This study evaluated the effects of blue light irradiation on the abundance of Nitzschia palea (N. palea). The relative abundance of N. palea increased when co-cultured with Microcystis aeruginosa (M. aeruginosa) and irradiated with blue light.
WATER ENVIRONMENT RESEARCH
(2022)
Review
Environmental Sciences
Haibo Yang, Jialin Kong, Huihui Hu, Yao Du, Meiyan Gao, Fei Chen
Summary: Water pollution is a serious problem affecting water environments, resources, and human health. Remote sensing technology provides temporal and spatial advantages for water quality monitoring, but faces challenges in atmospheric correction, data resolution, and retrieval models.
Article
Geosciences, Multidisciplinary
Vitor Ribeiro deSa, Katsuaki Koike, Tada-nori Goto, Tatsuo Nozaki, Yutaro Takaya, Toru Yamasaki
Summary: The study aims to identify and characterize mineralized zones in seafloor hydrothermal areas using limited metal content data, employing principal component analysis and three geostatistical methods. Results from a case study in the Okinawa Trough show two types of high metal content zones, contributing to a better understanding of SMS deposit formation mechanism and guiding submarine metal reserves and mining.
NATURAL RESOURCES RESEARCH
(2021)
Article
Geosciences, Multidisciplinary
Mohamad Nur Heriawan, Ahmad Ali Syafi'i, Asep Saepuloh, Taiki Kubo, Katsuaki Koike
Summary: This study developed a methodology for the regional detection of permeable zones in geothermal fields using multivariate geostatistical modeling of Radon-222 concentrations. By combining Radon concentrations with lineament density mapping and a fuzzy logic approach, the study successfully detected permeable zones that were confirmed by new drill hole data.
NATURAL RESOURCES RESEARCH
(2021)
Article
Geology
Hiroshi Takahashi, Shohei Albert Tomita, Katsuaki Koike, Hiroo Yoshiyama
Summary: This study focused on constructing a genetic ore deposition model for the Fuji vein in the Hosokura deposit, a low-sulfidation epithermal deposit in northern Japan. The model proposed that early stage mineralization was caused by mixing of neutral hydrothermal fluids with cold groundwater, leading to the formation of a hydrothermal alteration halo around the vein. Numerical simulation confirmed the processes of early stage cooling, middle stage vapor development, and late-stage hydrothermal brecciation in the formation of low-sulfidation epithermal deposits.
ORE GEOLOGY REVIEWS
(2021)
Article
Geosciences, Multidisciplinary
Koki Aizawa, Shinichi Takakura, Hisafumi Asaue, Katsuaki Koike, Ryokei Yoshimura, Ken'ichi Yamazaki, Shintaro Komatsu, Mitsuru Utsugi, Hiroyuki Inoue, Kaori Tsukamoto, Makoto Uyeshima, Takao Koyama, Wataru Kanda, Tohru Yoshinaga, Nobuo Matsushima, Kazunari Uchida, Yuko Tsukashima, Takeshi Matsushima, Hiroshi Ichihara, Dan Muramatsu, Yoshiko Teguri, Azusa Shito, Satoshi Matsumoto, Hiroshi Shimizu
Summary: Crustal earthquake ruptures tend to occur near fluid-rich zones, with ruptures initiated along the outer edge of low-resistivity fluid-rich zones leading to larger earthquakes. High-temperature fluid-rich zones arrest ruptures, while shallower low-temperature zones can either promote or arrest them. The distribution of mid-crustal fluids plays a role in the initiation, growth, and arrest of crustal earthquakes.
EARTH PLANETS AND SPACE
(2021)
Article
Geochemistry & Geophysics
Susumu Shibutani, Weiren Lin, Koichiro Sado, Akihiro Aizawa, Katsuaki Koike
Summary: This study reveals the fault characteristics and surrounding lithological units of the 2016 Kumamoto earthquake mainshock triggered by the Futagawa fault through a multiple-borehole drilling. It is found that there is more than 200 meters of normal faulting displacement along the Futagawa fault, and the 461 damage zone is identified as the primary candidate for the seismogenic faulting during the earthquake.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2022)
Article
Geochemistry & Geophysics
Katsuaki Koike, Takuya Kiriyama, Lei Lu, Taiki Kubo, Mohamad Nur Heriawan, Ryoichi Yamada
Summary: Two geostatistical methods incorporating geological information and semivariogram scaling law were developed to improve spatial estimation accuracy of metal contents at fine scale and successfully applied to two types of hydrothermal deposits. The methods showed significant advantages in increasing accuracy in high-content zones and detailing metal distribution in the deposits.
JOURNAL OF GEOCHEMICAL EXPLORATION
(2022)
Article
Geosciences, Multidisciplinary
Hiroshi Takahashi, Shohei Albert Tomita, Katsuaki Koike, Hiroo Yoshiyama
Summary: This study proposes a new multi-stage ore-deposition mechanism for low-sulfidation epithermal deposits, which is initiated by cold groundwater. Through geological modeling and numerical simulation, the researchers provide insights into the mineralization process and its evolution.
NATURAL RESOURCES RESEARCH
(2022)
Article
Geochemistry & Geophysics
Keiichi Ishizu, Weerachai Siripunvaraporn, Tada-nori Goto, Katsuaki Koike, Takafumi Kasaya, Hisanori Iwamoto
Summary: This study presents a cost-effective 3D marine controlled-source electromagnetic (CSEM) survey method for exploring seafloor massive sulfides (SMS). By using fewer receivers and a line configuration, the survey reduces costs while accurately mapping SMS.
Article
Geosciences, Multidisciplinary
Katsuaki Koike, Oak Yono, Vitor Ribeiro de Sa, Shohei Albert Tomita, Tatsuo Nozaki, Yutaro Takaya, Shogo Komori
Summary: This study applied neural kriging (NK), a deep neural network (DNN) based on a semivariogram learning criterion, to model the three-dimensional deposit structure of an active seafloor hydrothermal vent area. The results showed that NK outperformed traditional geostatistical simulation methods in predicting the location and extent of high-content zones. The spatial model generated by NK can contribute to the understanding of transport and enrichment mechanisms of target metals.
MATHEMATICAL GEOSCIENCES
(2022)
Article
Energy & Fuels
Riostantieka Mayandari Shoedarto, Yohei Tada, Koki Kashiwaya, Katsuaki Koike, Irwan Iskandar
Summary: Rare earth element (REE) analysis is an effective method for studying water-rock interactions and solute transport in geothermal and groundwater systems. This study focused on the hydrothermal flows in the recharge and discharge areas of a geothermal system in Southern Bandung, West Java (Indonesia). The results provide insights into the origin and speciation of dissolved REEs in the water samples, as well as the composition and alteration of the aquifers in the system.
Article
Geochemistry & Geophysics
Yusuke Ohta, Tada-nori Goto, Koki Kashiwaya, Katsuaki Koike
Summary: Many studies have been conducted to analyze the electrical properties of rocks using the Cole-Cole relaxation model. However, these models have limitations in representing the electrical flow mechanism in rocks and explaining the real behavior of rocks. In this study, we proposed a multiple-capacitance model expressed by an equivalent circuit based on the re-evaluation of Pelton's equation. The model, called the Double-Pelton equivalent circuit model (DPM), was successfully applied to complex conductivity curves of artificial samples, revealing the conductive mechanism of rocks with complex geometrical features.
EXPLORATION GEOPHYSICS
(2023)
Article
Geosciences, Multidisciplinary
Alaa A. Masoud, Taiki Kubo, Katsuaki Koike
Summary: This research identifies the geothermal characteristics and control factors of the Gulf of Suez, and determines areas with high geothermal potential through three-dimensional interpolation of temperature, geothermal gradient, and heat flux borehole data. It also highlights the influence of faults on the geothermal resource and provides insights for efficient management of binary power generation and enhanced geothermal systems in the region.
NATURAL RESOURCES RESEARCH
(2023)
Article
Geosciences, Multidisciplinary
Shizuka Takai, Taro Shimada, Seiji Takeda, Katsuaki Koike
Summary: In order to accurately estimate the remediation of accidental groundwater contamination, this study develops a geostatistical method to jointly clarify the contaminant plume and transmissivity distributions using both head and contaminant concentration data. The proposed method was demonstrated to be applicable and effective through two numerical experiments in a two-dimensional heterogeneous confined aquifer. The use of contaminant concentration data was found to be key in accurately estimating the transmissivity, and the uncertainty of the contaminant plume evolution was successfully evaluated.
MATHEMATICAL GEOSCIENCES
(2023)
Article
Engineering, Electrical & Electronic
Vu Thi Thu Thuy, Nguyen Thi Thu Ha, Katsuaki Koike, Nguyen Thien Phuong Thao, Pham Ngoc Trung, Dinh Xuan Thanh
Summary: This article aimed to develop appropriate models using Sentinel 2A images to estimate the water content and grain size of surface sediments on the Red river delta. The study found correlations between spectral reflectance and water content/grain size, and accuracy of the models was verified. Maps of water content and sediment type distributions were produced using the models.
IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING
(2022)
