Our cameras can view the entire earth – if we only look at a local level, we miss the global effects that humans cause
Images from USA and Bolivia show incredible usage patterns
Only 40 years ago did mankind achieve the ability to view our earth in one picture
Small blue marble images are some of the best legacy of the Apollo missions
Today, we have daily observations of our planet to track changes
Global change effects – ‘hole’ in clouds caused by Munich city heat: “Cities cause their own weather”
State of the art image resolution = 1m – we can see people in crowds in Munich’s cathedral square
All of us do ‘Remote sensing’ every day – in the super market. You cannot touch every piece of fruit, but you do eyeball it
Like shoppers, we need all types of data – satellites can see more than the human eye, e.g. infrared, ultraviolet in multiple channels. We can record the spectral signature of, say, sand vs. a pond. In visible wavelengths, there is not much difference between these. But in IR, there are great differences, so these wavelengths allow us to discover much more information. If you could view apples in the market in IR, you’d know already which ones were fresh or not.
Our satellites can measure e.g. sulphur emissions
One instrument may only have 1-km resolution in visible light, but much better in another – and can help us determine NO2 levels, for example.
Sat images can help miners determine where to dig; Sea temperatures, vegetation growth year-to-year, minute-to-minute variations in clouds/storms
Commercially available resolution of 40cm cannot show individual people
Radar remote sensing
TandemX and TerraSAR-X are flying in formation, a special orbit – separated side-by-side by only 150-400m. They can look below in 3D to develop elevation models with a resolution of 12m. In 2004, the best we could do was about 1km!
Radar images are taken from a horizontal perspective, so we get highly accurate (+/- 7 mm) but rather strange-looking images. We can measure how fast glaciers are receding!
Images can even detect cultural patterns! No reduction in smog over Chinese cities on the weekend, unlike in America or Europe!