Water Optics and Water Colour Remote Sensing

Abstract

Abstract:The editorial paper aims to highlight the main topics investigated in the Special Issue (SI) "Water Optics and Water Colour Remote Sensing". The outcomes of the 21 papers published in the SI are presented, along with a bibliometric analysis in the same field, namely, water optics and water colour remote sensing. This editorial summarises how the research articles of the SI approach the study of bio-optical properties of aquatic systems, the development of remote sensing algorithms, and the application of time-series satellite data for assessing long-term and temporal-spatial dynamics in inland, coastal, and oceanic waters. The SI shows the progress with a focus on: (1) bio-optical properties (three papers); (2) atmospheric correction and data uncertainties (five papers); (3) remote sensing estimation of chlorophyll-a (Chl-a) (eight papers); (4) remote sensing estimation of suspended matter and chromophoric dissolved organic matter (CDOM) (four papers); and (5) water quality and water ecology remote sensing (four papers). Overall, the SI presents a variety of applications at the global scale (with case studies in Europe, Asia, South and North America, and the Antarctic), achieved with different remote sensing instruments, such as hyperspectral field and airborne sensors, ocean colour radiometry, geostationary platforms, and the multispectral Landsat and Sentinel-2 satellites. The bibliometric analysis, carried out to include research articles published from 1900 to 2016, indicates that "chlorophyll-a", "ocean colour", "phytoplankton", "SeaWiFS" (Sea-Viewing Wide Field-of-View Sensor), and "chromophoric dissolved organic matter" were the five most frequently used keywords in the field. The SI contents, along with the bibliometric analysis, clearly suggest that remote sensing of Chl-a is one of the topmost investigated subjects in the field.

Remote Sensing Applications in Monitoring of Protected Areas: A Bibliometric Analysis

“…A bibliometric analysis helps identify research gaps and directions in one certain area [49]. In recent years, studies have applied this method to evaluate the research trends of remote sensing and its application in different scientific fields [50][51][52]. For instance, Zhang et al [53] combined the new index (geographical impact factor) and traditional bibliometric methods to study the global research trends in remote sensing studies.…”

Use of Hyperspectral Remote Sensing to Estimate Water Quality

“…Hyperspectral remote sensing has been used to characterize algal blooms [21] and assess ammonia dynamics for wetland treatments [22,23]. Tilley et al [23] also developed remotely sensed hyperspectral signatures of macrophytes to monitor changes in wetland water quality predictors of total ammonia concentrations [24] Hyperspectral remote sensing has similarly been used to determine water quality parameters like temperature, chlorophyll a, total suspended solids [25,26], total phosphorus [27,28], and turbidity; Lillesand et al [29] and Lathrop and Lillesand [30] studied lakes and reservoirs, estuaries [31,32], and tropical coastal areas [33,34]. Other water quality studies on monitoring surface water bodies in different parts of the world (e.g., [35][36][37][38][39][40]) have all been interested in modeling and development of concentration distribution maps for different water quality parameters based on its reflectance characteristics.…”

Retrieving the Lake Trophic Level Index with Landsat-8 Image by Atmospheric Parameter and RBF: A Case Study of Lakes in Wuhan, China

“…Available water resources, including rivers, reservoirs, lakes, coastal waters, and oceans, are emerging as a limiting factor, not only in quantity, but also in quality, for human development and ecological stability. The decline in water quality has become a global issue of significant concern for hydrological cycles [1,2]. Conventional in-situ sampling is expensive, and laboratory work is time-consuming.…”