Several sensors are used to visualize and study the Gulf Stream. The most direct method of viewing the Gulf Stream remotely is by using a thermal infrared band to measure sea surface temperatures (SST). However there are several other sensors that can aid in visualizing the Gulf Stream that do not use thermal infrared.
Sensors Used to Study the Gulf Stream
SeaWiFS (Sea-viewing Wide Field-of-view Sensor)
SeaWiFS was designed to observe ocean color. Its eight spectral bands are optimized for studying chlorophyll. Chlorophyll levels are tied to the amount and types of phytoplankton. Phytoplankton thrive where there are plenty of nutrients. Because cold water tends to have more nutrients than warm water, areas with high levels of chlorophyll tend to indicate that the water temperatures are cooler.
Read more about the relationship between chlorophyll, phytoplankton, and water temperature here.
Ocean Color
AMSR (Advanced Microwave Scanning Radiometer)
AMSR uses passive microwave to measure SST. At certain frequencies, the amount of microwave radiation that rises from the ocean is highly correlated to SST. Although the amount of radiation also depends on sea surface roughness and atmospheric conditions, these effects can be removed because they have a distinct signature.
Read more about the microwave measurement of sea surface temperature.
Learn more about the AMSR instrument and the satellites that have carried it.
Thermal Infrared
AVHRR uses thermal infrared (TIR) bands to measure SST. Both the temperature and emissivity of the ocean surface influence the TIR measurements. But because the emissivity of water has a well known and consistent value, it is easy to get an accurate reading for SST from the TIR radiance measurements.
Read more about the AVHRR sensor and the current Pathfinder project.
Learn about the math and physics behind turning readings into SST values.