NASA release new world salinty from satellite map

[Studiot]

Don't know whether this belongs in chemistry or Earth science but there has been discussion about salinity here.

http://www.bbc.co.uk/news/science-environment-15033532

 

[DrClapeyron]

Looks like a cool map. I think I can see the equator and the antarctic gyre. Drop off in salinity near coasts due to fresh water influx from rivers (Amazon in Brazil looks kind of obvious). India looks interesting: less saline off the east coast (brahma and indochinese rivers), and more saline off the west coast (indus river being the only major river). I am not seeing any deep sea features like mid-oceans ridges. Mediterranean must have very ristricted flow even with the Nile pouring into it.

Wonder how these could be used to measure droughts like we have here in Texas. Hopefully the project produces many more years worth of images without

 

[Andre]

The mediterrian is renowned for it's saline concentration, due to high evaporation and limited drainage.

It could also be predicted that the horizontal bands with less saline water in the Pacific and atlantic situated just north of the equator around 5 degrees lattitude will have shifted south of the equator in about six months,

 

[Gannet]

Red and yellow colours denote areas of higher salinity; blues and purples represent areas of lower salinity. Areas coloured black represent gaps in the data.

Am I correct in assuming that the more or less saline are in relation to normal oceanic surface salinity and that all the purples are roughly the same salinity?

 

[Studiot]

What do you mean by normal? Do you really mean average?

The salinity map shows the 'normal' salinity for the location. That is the whole point arctic and certain equatorial zones have lower than average salinity, and certain tropical zones have higher than average salinity at all times.

 

[Gannet]

Standard sea water salinity is 35 psu (practical salinity units)


Fromhttp://nsidc.org/seaice/characteristics/brine_salinity.html"

The average salinity of the ocean typically varies from 32 to 37 psu, but in polar regions, it may be less than 30 psu.

I went to the NASA Aquarius site hoping that it would provide more info and a color scale; but, computer at work locked up trying to load it.

 

[D H]

Am I correct in assuming that the more or less saline are in relation to normal oceanic surface salinity and that all the purples are roughly the same salinity?

The satellite has only been operational for two and a half weeks. That is almost certainly uncalibrated quick-look data. Two and a half weeks is not enough time to calibrate the sensors. The mission scientists almost certainly have an idea what the calibrations should be, but in remote telemetry those pre-launch calibrations can often be off by quite a bit, particularly so in the case of a new class of sensors.

 

[D H]

Continuing with my previous post:

Fortunately there is plenty of ground truth data that be used to calibrate those new satellite sensors. There are lots of scientific buoys out in the oceans equipped with various sensors such as salinity sensors and with GPS receivers. Oceanography research vessels add to the mix.

Scientists have been measuring salinity for quite some time now. Here, for example, is a snapshot of the global sea surface salinity for Sept 26 2011:

[URL]http://www7320.nrlssc.navy.mil/global_ncom/Links/glb/sal_glb8_3b_2011092600_0000m.gif[/URL]

The next link is an animated gif of the last year's such snapshots (I made it a link, rather an image, because this animated gif is 365 times as big as the above one day image):

http://www7320.nrlssc.navy.mil/global_ncom/anims/glb/sss12m.gif

The site http://www7320.nrlssc.navy.mil/global_ncom/ contains global ocean views as well as views that focus on specific oceans. For example, here's the Bay of Bengal, 12 month animated gif:

http://www7320.nrlssc.navy.mil/global_ncom/anims/ben/sss12m.gif

 

[Gannet]

Thank you DH for the insight and links