Why is altimetry important for fishing?
We first talked about ocean altimetry in 2016 in our blog post. Why should I care about altimetry? The surface of the ocean is not flat. There are high spots and low spots. Altimetry imagery indicates the ocean surface height in relation to mean sea level in centimeters. By studying the latest altimetry imagery, you can locate areas of upwelling and downwelling and the location of ocean current features and eddies.
Where does altimetry data originate?
There are various satellites equipped with instruments called altimeters. These instruments are incredibly accurate and measure the ocean’s surface’s height from space to within a few centimeters.
How often is 20Echo.com’s altimetry data updated?
The model is updated once a day.
Why doesn’t cloud cover bother Altimetry readings like it bothers SST and Chlorophyll readings?
Altimetry is measured using an altimeter. An Altimeter works by sending out a microwave pulse, bouncing it off the ocean’s surface. Since a microwave can go straight through clouds and still measure the return signal, it is not impeded by cloud-cover like the instrumentation used to measure sea surface temperature and chlorophyll.
What does “upwelling” mean?
Upwelling is a phenomenon where water from the deep ocean rises to the surface. This cold, deep ocean water is densely packed with nutrients. When it rises to the surface and exposed to sunlight, microscopic plants (phytoplankton) and animals (zooplankton) can proliferate. Squid and baitfish feed on these tiny animals, and in turn, attract larger pelagic species.
How do you find areas of upwelling?
Upwellings are areas on the SSH (sea surface height) chart that are lower than surrounding areas. It’s a bit counter-intuitive, but water in these “low spots” is rising to the surface to achieve equilibrium. Try uploading a photo on https://20echo.com/
Where, in general, are the best altimetry areas to fish?
Generally, the best areas to fish are in the intermediate zones between regions of upwelling and convergence areas. These neutral areas — between the highs and away from the center of the low — is where the food chain will have time to develop.
How can altimetry be used in conjunction with SST and Chlorophyll data?
Where there are upwellings the water is usually cleaner, with less chlorophyll, and colder since it’s coming from deep in the ocean.
How can altimetry data be used as a substitute for SST data when there is cloud-cover?
Altimetry data overlays won’t line up precisely with SST data but it will be close. We would much prefer using altimetry data to find temperature changes than nothing at all!
What else should I know about Sea Surface Height data when thinking about eddies & currents?
The real secret — if there is one — is to understand how the altimetry level you see is created and how that will affect the data’s accuracy. Once you know the data sources’ limitations, you will understand when and how to use it properly. Remember Upwellings have LOWER elevations than Downwellings and you always want to fish where the two meet and form current or in an upwelling where nutrients are coming up from the deep! If you are still wanting to know more about Ocean Altimetry click here for a great video on the subject from the European Space Agency.
Muchos Gracias for your post. Really looking forward to read more.