Does NASA use sub-standard infrared spectrometers?

Question

In http://www.weatherquestions.com/Roy-Spencer-on-global-warming.htm, Roy Spencer says

"The Earth-orbiting instruments for measuring the Earth's radiative components are not quite accurate to measure the small radiative imbalance that is presumed to exist."

The radiative imbalance is 0.8 W/m^2 out of approximately 235 W/m^2 or about 0.3%. The infrared fraction is larger, but let's stick with the worst case. An ordinary quality control FT spectrometer easily achieves a S/N ratio of 1E4 and a research grade instrument achieves a SNR of 1E5 or 1E6 with extra effort. A grating instrument will achieve the same sensitivity at the cost of resolution and bandwidth. Does NASA use inferior equipment (SNR < 3E3 when SNR ~ 1E6 is available) or is Roy Spencer making a false statement?

Answer 1

Your link just gives me a &quot;page not found&quot;.

I am sure there are other sources of error besides the S/N ratio of the spectrometer.

Satellites use equipment that will fit in the satellite, is extremely light weight, is able to survive the temperature extremes and radiation in space, doesn&#039;t use too much power, works as well in a vacuum as in the air and can survive the vibration and G forces of launch. This usually severely limits what can be used and drives the cost way up.

Answer 2

NASA uses a lot of sub-standard equipment. They are using  outdated computers and equipment and they have become unreliable.

Answer 3

I&#039;m pretty confident the answer to your question would be &quot;no&quot;.

I&#039;ve been involved in several NASA projects over the years and they always specify state-of-the-art high-end quality instrumentation for anything they put into orbit.  Saving a few dollars on instrumentation, when you&#039;re spending millions to launch a vehicle into orbit is NOT something any NASA project manager would accept.  Budgets are always tight, but NASA doesn&#039;t nickel and dime things as important as that.  They&#039;ll let a project drop or be late rather than waste time collecting inferior data.

I can&#039;t say for sure if Roy Spencer is making a false statement, in this case, but Spencer is somewhat infamous for a previous mistake he made:

http://www.nytimes.com/2005/08/12/scienc...

Answer 4

all instruments need to be calibrated on a regular bases.

how do you calibrate a instrument in orbit.

also instruments calibration changes with operating conditions

so if you calibrate a instrument on the ground, in air. with humidy, and a level of heat.

how do you tell if the same instrument operating in space is still in calibration.

Answer 5

Roy Spencer is telling the truth. NASA doesn&#039;t have the best equipment possible. They are on a very tight budget, and are primarily spending the money on space missions. The technology however, does give a reasonable idea of the radiative components if you were to compare them together using the same machine.