Prof. Chen Wenpin of South China Agricultural University, published a research on puerh storage in The Proceedings of the 2nd International Conference of Yunnan Puerh in 2007. He did "a tale of cities"
Guangzhou, Shanghai, Kunming and Hong Kong, with relative humidity ranging from 68% to 85%. I once took a look at it but don't have access to it now (it's in a password required database). He did some short term observation (several years, less than 10, I think) and made a table to compare the liquor color, leaf color, etc. Since he did this, I guess he is doing some longer term study now.
But I think it depends on how detailed the measurements meant to be (e.g., whether it's observation of color and tastes or chemical analysis of components) and the goals of the study. There have been a lot of anecdotal observations among Chinese tea drinkers in different cities. But Chen's study has more strictly controlled environments I suppose, and the results are somewhat consistent with the anecdotes among tea drinkers. His study seems quite general. Other people, if doing similar studies, may choose to explore various factors, such as different taste profiles, high-grade vs. low-grade leaves, plantation vs. arbor tree leaves, etc.