Honest question.
Why does weather behave different over oceans when compared to land?
Why does weather behave different over oceans when compared to land?
I think this is a data issue, not a weather issue.
The data they are using over oceans comes from microwave scatterometers, which use radar to measure disturbances of the ocean surface caused by near-surface winds. Basically, the power of the radar return is affected by the interaction of the radar waves with the irregularities in the water surface (https://earth.esa.int/applications/data_util/SARDOCS/spacebo...). To get a wind speed and direction from the radar power, you have to hit the surface from several different angles and perform an inversion.
There are several ocean winds space missions that do this continuously from ~90-minute Earth orbits. For reference, one is QuikSCAT -- http://science.nasa.gov/missions/quikscat/
There is no analogous sensor that works over land. Hence, the data over land is not nearly as uniform, dense, and regularly observed.
All that said, this particular visualization seems to have a calibration issue, because the land winds seem to be off in magnitude. I'm not enough of an expert to know if this is a problem with their data merging, sensor selection, stratification (e.g., winds at land surface may be lower than at sea surface, but up 50m they may be comparable), or something else.
You can get other surprising things from remote sensing over oceans, including salinity, temperature, and incredibly precise elevation.
The land data is scarce in e.g. the Sahara, but the density over western Europe is pretty high. The land based data is continuous as well, and not affected by cloud cover.
Another issue with in situ sensors is calibration and uniformity. Unless they were installed by a central authority, they are likely to all be different. This makes analysis harder.
There are also strong heat / surface moisture gradients on land (think edges of forests, cities, coasts), which play a big role in convection.
By comparison, the ocean is an infinite plane so the dynamics are much more dependent on large scale forcings like the Earth's rotation and there is less local variability.