Register for an account

X

Enter your name and email address below.

Your email address is used to log in and will not be shared or sold. Read our privacy policy.

X

Website access code

Enter your access code into the form field below.

If you are a Zinio, Nook, Kindle, Apple, or Google Play subscriber, you can enter your website access code to gain subscriber access. Your website access code is located in the upper right corner of the Table of Contents page of your digital edition.

The Sciences

Saline the ocean blue

Newsletter

Sign up for our email newsletter for the latest science news

In June, NASA launched the Earth-observing satellite Aquarius, designed to observe and measure the salinity content of the ocean surface. This turns out to be important because salty water flows differently than pure water, and how the currents interact drives a lot of the way heat is transferred across the Earth's oceans. And that drives a lot of climate behavior, including climate change. Scientists just released the first global map of ocean surface salinity, showing surprising (to me) variations across the planet:

aquarius_oceansalinity.jpg

Neat! [Click to verucafy.] In the map, blue/purple is lower salinity, and red/orange is higher concentrations. The average value is about 35 grams of salt per kilo of water (about 0.6 ounces of salt to one pint of water), but it varies a lot. And it's not just latitude dependent, which would've been my first guess. The Pacific equatorial waters are low in salt, but the levels in the Atlantic are higher. North Pacific is low, north Atlantic higher. The western Indian ocean is high, the eastern part low. Apparently these measurements are tough to make. Aquarius has an instrument which measures the emission of the ocean surface in the infrared. Salty water doesn't emit IR as efficiently, so the salinity can be measured exploiting this. However, waves on the surface mess this up, so the spacecraft has a way to measure how strong the waves are (using what's called a radar scatterometer, which is totally cool name for an instrument) so they can account for that as well. Observations like this are crucial for us to understand just how our fiendishly complex planet works. Especially now, when our climate is changing, and those changes are evident even year by year. Image credit: NASA/GSFC/JPL-Caltech


Related posts: - The lumpy, 3D Earth - Arctic ice at the second lowest extent since 1979 - Icy swirls around a patient volcano - Attack of the (cy)clones

    2 Free Articles Left

    Want it all? Get unlimited access when you subscribe.

    Subscribe

    Already a subscriber? Register or Log In

    Want unlimited access?

    Subscribe today and save 70%

    Subscribe

    Already a subscriber? Register or Log In