Basically, if I were to write a thesis about the three CSIs, I would begin by noting that they are all filmed in LA, but all utilize very different images. I would go on to ask, "Is this how Americans perceive these different locations?" (This is the kind of question professors ask, rather than, Is this what these locations are really like? Because if you answer the last question, "Yes," *zap* no more thesis.)
For example, CSI: Miami is all bright, glowing sunlight. Everyone is always squinting. The CSI lab is made of glass through which the glowing, bright sunlight reflects and refracts; the lab is filled with shiny objects upon which the sunlight glitters. CSI: Las Vegas uses darkness in almost the same way: long shadows, dark punctuated by flashing lights. Their lab is a low-ceilinged warren with a circular format.
And in CSI: New York, it is always raining. Or at least, overcast. Gloomy with occasional afternoon sunlight that never seems to reach the ground. And the lab is a warehouse.
The first question, as noted above, is, Is this what Miami, Las Vegas and New York are really like? Well, possibly. The second question is, Is this how most people perceive these various cities: are the producers digging into some deep, Jung-like American concept of Miami, Las Vegas and New York? If you gave Americans Rorschach-like tests and asked, "What is the first word that comes to mind when you hear Miami, Las Vegas and New York?" would they say, "Sun," "Night on the town" and "Rain"?
Possibly. Those sociologists and humanists who have been brainfried by Marxist theory, will tell you that television reinforces (or creates) these images, but I think it is far more likely that the producers chose such images to create the impression of a place, enabling the suspension of disbelief. (Because, after all, Miami is not the same thing as New York.) We are, as the audience, supposed to believe that Caruso, Sinese and Petersen never, ever see each other. Of course, our (supposed) ignorance makes us pawns of evil mass media. But since it is only supposed, I don't really think it is much of an issue. The point is, fiction doesn't work at all if you keep looking at the scaffolding. And despite the attempts of higher education to turn everyone into skeptical literalists, it would be a pity for the arts.
In any case, I think the producers, writers, directors, etc. believe that Americans have an idea of region that the shows/episodes then play on. Which is pretty fascinating in its own right. It means that Americans associate rats, sewers, rain, sidewalk artists and art crimes with New York; sun, hurricanes, boats, drugs, drugs, drugs and hotel crimes with Miami; night, gambling, serial killers, weird families and bugs with Las Vegas (although the latter has more to do with Grissom than with Las Vegas). And who is to say Americans are wrong?
The second fascinating thing is that although the shows are similiar in many ways, and although a truly awesome amount of each episode takes place indoors, the overarcing image (this is Miami, this is New York, this is Vegas) is retained mostly through light: the amount of glittering sunlight, absence of sunlight and damp sunlight in each episode. Each show carries a tone, of sorts. It could also explain why I can't get into CSI: New York, no matter how hard I try. I mean, rain? Dampness? Oblique sunlight? It's all very atmospheric, but I just can't get excited about it. (Of course, I live in the Northeast so I see it everyday.)