Looking for something else, I found an interesting paper on urban CO{2} concentration: http://www.atmos.berkeley.edu/~inez/MSRI-NCAR_CarbonDA/papers/barnet_refs/2000GL012632.pdf It turns out urban CO{2} studies have become somewhat popular and worthy of study. Obviously the concentration of CO{2} in developed countries should peak around cities as well as combustion power plants. But this 2001 paper points out over Phoenix: CO{2} concentrations show constant above 850 hPa (~5,000 ft) maximum CO{2} temperature increase around 750 hPa (~8,000 ft) surface warming from CO{2} << than other effects Urban CO{2} studies provide insights specific to the warming effects of CO{2}. One interesting side is the the degree that ". . . our simulations with the Chau et al. model do not include water vapor feedbacks that typically elevate the global temperature response to increased CO{2}. Furthermore, there is no evidence that atmospheric moisture levels in Phoenix have increased at the temperatures have risen." Gosh, a city in an Arizona desert does not have more water at higher temperatures? . . . I'm shocked. I love how professional papers can understate the obvious. <grins> Regardless, the importance of OCO-2 makes even more sense. Google found another 2012 article about urban CO{2} in London. The reason is these local concentrations of CO{2} means we can study isolated areas where the concentrations are in the projected ranges of global CO{2}. Thus heating effects in dry, wet, cloudy or other variables and their effects with CO{2} can be used to improve and tweak the global models. CO{2} is not the only greenhouse gas and though I understand the global, black-body model, real life is more complex. So I appreciate these step-wise improvements in our understanding. Bob Wilson
Actually I am surprised that Phoenix air has not become more humid. It is a city of lawns and golf courses in what would otherwise have been desert. Perhaps it is a similar signal/noise ratio problem that makes global humidity increases difficult to quantify.
