Remote Sensing Systems for Ocean: A Review (Part 1: Passive Systems)

Abstract

Reliable, accurate, and timely information about oceans is important for many applications, including water resource management, hydrological cycle monitoring, environmental studies, agricultural and ecosystem health applications, economy, and the overall health of the environment. In this regard, Remote Sensing (RS) systems offer exceptional advantages for mapping and monitoring various oceanographic parameters with acceptable temporal and spatial resolutions over the oceans and coastal areas. So far, different methods have been developed to study oceans using various RS systems. This urges the necessity of having review studies that comprehensively discuss various RS systems, including passive and active sensors, and their advantages and limitations for ocean applications. In this paper, the goal is to review most remote sensing systems and approaches that have been worked on marine applications. This review paper is divided into two parts. Part 1 is dedicated to the passive RS systems for ocean studies. As such, four primary passive systems, including optical, Thermal Infrared (TIR) radiometers, microwave radiometers, and Global Navigation Satellite Systems (GNSS), are comprehensively discussed. Additionally, this paper summarizes the main passive RS sensors and satellites, which have been utilized for different oceanographic applications. Finally, various oceanographic parameters, which can be retrieved from the data acquired by passive RS systems, along with the corresponding methods, are discussed.

Deep blue artificial intelligence for knowledge discovery of the intermediate ocean

“…Further combined with passive ocean color remote sensing and in situ biogeochemical buoys (Biogeochemical Argo, BGC-ARGO) and other observation means, it is expected to achieve the threedimensional detection and high-precision inversion of bio-optical and physical parameters in four-dimensional space time within the ~100-m depth of the global ocean for the first time (Chen et al, 2021b). For a more intuitive understanding of the abovementioned spaceborne sensor, the characteristics of these satellite sensors are collected and summarized in Table 1 (Amani et al, 2021;Amani et al, 2022a;Amani et al, 2022b;Amani et al, 2022c).…”

Remote Sensing Systems for Ocean: A Review (Part 2: Active Systems)

“…The column water mass on the combined ocean and atmosphere is called the Ocean Bottom Pressure (OBP) [171]. OBP variability is due to three important factors [172]: (1) variations in wind stress, curl, and circulation (this is called internal ocean mass redistribution), (2) water mass entering and leaving the ocean (this is considered as part of the global water cycle), and (3) atmospheric mass exchange between the ocean and land. Although direct measurement of OBP is difficult, GRACE can effectively measure global OBP (see Fig.…”

“…There are three steps to study the bottom topography using SAR imaging systems: (1) finding the connection between the OSC and underwater topographic features; (2) accurate hydrodynamic modulation of the ocean surface variations through the OSC; and (3) creating a relationship between the microwave signal and the sea surface [246]. In [247], the gridded bathymetry information was automatically derived from SAR data.…”

“…RS systems can be generally divided into two broad groups of passive and active. The Part1 of this review paper was about the passive systems for ocean studies (see [1] for more details). In this part of the paper, various active RS systems for ocean M. Amani* and S. Mahdavi are with the Wood Environment and Infrastructure Solutions, Ottawa, ON, Canada, K2E 7L5 (email: meisam.amani@woodplc.com; sahel.mahdavi@woodplc.com).…”