In addition to an imaging camera, a radiometer would take the first direct measurements of how much sunlight is reflected and emitted from the whole Earth (albedo). This data could constitute a barometer for the process of global warming. The scientific goals expanded to measure the amount of solar energy reaching Earth, cloud patterns, weather systems, monitor the health of Earth's vegetation, and track the amount of UV light reaching the surface through the ozone layer.
While NASA's Inspector General questioned the cost/benefit ratio of the project (quite rightly -- that's his job) the National Academy of Science, queried by Congress, found the mission to be "strong and scientifically vital."
Nevertheless, the satellite was mothballed for eight years under the Bush administration, and remains in limbo today.
The information the satellite would provide is phenomenally important, and should be important to "skeptics," as well. Directly measuring the Earth's radiation budget (energy in versus energy out) gives you a direct, observed value of global warming, magnitude and sign. By tracking our albedo, vegetation, and cloud patterns, the satellite would monitor three of the most important feedbacks in climate change.
If you want an easy way to tell who not to trust in a scientific debate, it's the side that's afraid of better measurements. Those that want to softpedal global warming or deny it entirely always claim frustration with the lack of clarity (as they see it) in the science, but where's their drive to collect observations and achieve a better understanding? DSCOVR waits in a warehouse, but climate change isn't waiting.
I'm a longtime fan of Triana myself -- I like to watch the planet, and the ISS pictures are fragmentary. I'm itching to see the Hubble movie just out, which will show us a bit from a higher point. But still, Triana's position is ideal for imaging the whole daytime planet.
ReplyDeleteThose of us waiting for it are in good company (Robert Park has been talking about this for a long time, most recently March 12th, see
http://bobpark.physics.umd.edu/).
It's not the full answer, and we should be careful not to oversell it because even if it gets into place and is used, it doesn't provide all the information needed.
Bob Park has a comment about one objection I'd never heard before: "The opposition to DSCOVR is based on the fact that the L1 is a retro-reflection (hotspot) point. And so it is, but DSCOVR will not be exactly at the L1 point. It will orbit the L1. In any case it is possible to analyze hotspot reflections."
Triana isn't all we've needed; it wasn't designed with infrared band instruments, as was pointed out to me when I asked about it a while back:
"Triana would have given you full-disk albedo, but would have done nothing for the infrared side of the budget. --Ray Pierrehumbert at RealClimate
http://www.realclimate.org/?comments_popup=686#comment-131064
I think it was Gavin at RC who also noted that for a complete infrared balance you need both an instrument on the sunlit side _and_ one on the night side.
So it'd be a start. A start we could have made almost a decade ago. And yes, it would have answered a lot of the questions people did, or didn't, want answered by now.
Good points all. You don't want to build up any one instrument or experiment as the thing that will clear the cobwebs away and will give us all the answer -- that's not how science works.
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