Ocean temperature monitoring: an important basis for assessing marine ecosystems

The ocean covers 70% of the Earth's surface and is the largest natural ecosystem on Earth. Due to the complex and ever-changing marine environment, environmental monitoring and emergency early warning are crucial. Among these, the monitoring and forecasting of marine hydrological information using satellite remote sensing technology is vital for the development of marine resources, the growth of the marine economy, the protection of marine ecosystems, and the safeguarding of maritime rights.

Marine environmental remote sensing monitoring

Due to the vastness and depth of the ocean, traditional ground-based monitoring methods are insufficient to meet the needs of marine environmental monitoring. Remote sensing technology offers a wider reach and higher efficiency than traditional survey techniques in addressing marine environmental issues, possessing unique advantages. First, it is not limited by geographical location, weather, or human factors, and can cover geographically remote areas, areas with harsh environmental conditions, and areas where routine surveys cannot be conducted directly due to political reasons. Second, satellite remote sensing acquires a vast amount of marine information, providing large-area sea surface images, with each frame covering thousands of square kilometers, which is extremely beneficial for marine resource surveys, large-area mapping, and pollution monitoring. Third, satellite remote sensing can periodically monitor ocean currents, changes in sea surface temperature fields, fish migration, and pollutant transport.

Ocean temperature monitoring

In marine environmental research, ocean surface temperature (OST) is one of the most important indicators for marine environmental monitoring. Ocean temperature refers to the temperature of seawater, and its variations can be large-scale seasonal and interannual, or small-scale localized. Ocean temperature has a significant impact on marine life and ecosystems and is a fundamental element of marine climate research. Using remote sensing technology, we can acquire global ocean surface temperature data. This data can be used to monitor ocean temperature trends, predict climate change, and assess the health of marine ecosystems. Furthermore, ocean surface temperature data can also be used to monitor ocean circulation and extreme weather events such as marine storms.

Xi'an Institute of Optics and Precision Mechanics CAS Aerospace Science and Technology Group Co.,LTD - Xiamen Ocean Temperature Monitoring

Traditional sea surface temperature observations rely on manual measurement methods, which are costly in terms of manpower and time, and have limited coverage. Remote sensing satellites can accurately retrieve sea temperature by extracting thermal infrared information from the sea area within the thermal infrared band, and have the advantages of rapid coverage, large data volume, and continuous observation. These images allow for the analysis of temperature change trends and patterns, enabling predictions of future ocean temperatures and providing data for global climate change research. Furthermore, monitoring ocean temperatures provides crucial meteorological and marine environmental information, offering a basis for marine resource development and maritime safety.

The sea surface temperature in this paper was calculated using the split-window method (MCSST). First, the brightness temperature was calculated from the two thermal infrared band values ​​using Planck's equation. Then, fitting parameters were obtained from measured data and substituted into the split-window method formula to obtain the result. As shown in the figure, the sea surface temperature near Xiamen City was generally higher in early July and decreased at the end of August.

By acquiring data through satellite remote sensing and combining it with the electromagnetic wave characteristics of marine elements such as ocean temperature and depth, ocean currents, seabed topography, salinity, and dissolved oxygen, we can conduct in-depth research on seabed topography, ocean temperature and meteorological factors, and marine life. This allows us to understand the dynamic changes of the marine ecosystem from a macroscopic perspective, providing new technical means for marine research and opening up new research fields.

The 21st century is the century of the ocean, and satellite remote sensing technology is the best way to fully utilize existing data and information resources. It is a key technology and important means to achieve sustainable development of marine resources and the environment. It plays an irreplaceable role in global change, resource surveys, environmental monitoring, and forecasting.