Old Commerce and the Mall of America

Two months ago, I took a family vacation to Minnesota & Wisconsin. As we spent most of our time in the Twin Cities area, we devoted half a day to wandering around the Mall of America in Bloomington (in Minnesota, near Minneapolis). It was the first time that I had gone to a shopping mall with my whole immediate family in over 10 years, especially because the main shopping mall that we used to frequent where I grew up closed a few years ago and was already on life support a few years before that.

There are several reasons, beyond mere nostalgia for my childhood or the lightness of mind from being on vacation, that I felt particularly gratified to visit the Mall of America, even though I didn't directly try its novelties like its indoor amusement park and I'm generally not into shopping for its own sake. These reasons are as follows.

• I had noticed over the last few years that indoor shopping malls in the US were following a K-shaped trajectory. Malls serving people with high incomes (including one that I needed to visit a few times near Sacramento to be fitted for a suit for a wedding) were thriving, as they could afford to support more boutique stores & "experiences" to attract visitors, while those serving people with low & middle incomes (including the one that my family & I used to frequent when I was growing up) were struggling & ultimately closing. In recent years, when I happen to have visited indoor shopping malls, I have been sad to see the decline of struggling malls catering to people with low & middle incomes, and I have felt out of place at thriving malls catering to people with high incomes. The Mall of America seemed to be an exception to that, because it had many stores selling goods at price points affordable to people with middle incomes, not just people with high incomes, so I could feel instinctively welcome there, yet it was also thriving.
• Most large indoor shopping malls, including the Mall of America, have been built to hold 4 anchor stores. Many indoor shopping malls have encountered financial troubles when one of the anchor store tenants leaves & isn't replaced, with those troubles compounding when more anchor store tenants leave & aren't replaced. By contrast, the Mall of America only has 2 out of 4 anchor stores occupied, yet the mall as a whole still thrives.
• Perhaps most importantly, unlike most indoor shopping malls that have "pivoted" to either luxury goods or cutting-edge consumer technology to attract visitors, the Mall of America focuses on simpler stores & attractions, like clothing/fashion, books, simple toys & games, and food to attract visitors, making it feel like a relic of the second half of the 20th century, yet it thrives. I was particularly taken to see & enter a Barnes & Noble bookstore, which I hadn't been to in 15 years, so much that I bought a book on a whim, which is notable because I almost never buy anything on a whim (though that book also happened to be on my reading list and will likely become the subject of a future post on this blog). These features make the mall & its merchandise a welcome respite from the pervasion of Internet technology in most people's lives that steal people's data, addict people, make people frustrated & hopeless, and extract people's wealth (through things like surveillance pricing); I didn't feel like I needed to worry about these current-day problems with commerce & the implications for national politics while I was at that mall.

I suspect that these features are made possible by the mall's huge size being a novelty in itself supporting as many visitors as it has, with that novelty further reinforced by explicit novelties like the full-size indoor amusement park, aquarium, and movie theater. I also recognize that indoor shopping malls & national chains gutted small independent businesses in the second half of the 20th century, so although it may technically be true that businesses in indoor shopping malls then represented more freedom for consumers than current businesses, they do not represent a paragon of a kinder capitalism. Even so, visiting the Mall of America made me more confident that current commerce based on stealing people's data, addicting people, making people frustrated & hopeless, and extracting people's wealth to an unconscionable degree is an artifact and hopeful that there is a viable alternative that can return to the fore.

Dew Points and Dry Skin

The question that initially motivated my desire to understand correlations of different climates to geography was why San Francisco has a much warmer winter season and cooler & drier summer season than DC despite the two cities being within 1.5 degrees of latitude of each other. A corollary to that question is why many people, including me, experience dry skin during the winter season in most of the northern half of the contiguous US but not at any point of the year in lowland California, even though California experiences very dry summer seasons. The answer has to do with dew points, but it is a little more subtle than simply saying that the dew point in the winter season is higher in lowland California than in most of the northern half of the contiguous US. Follow the jump to see more.

Interpreting a Model's Statistical Significance with Many Parameters

This post is about the situation when developing statistical models, in which parameters are given with their means and standard errors, of ensuring that a data analyst does not mistakenly reject the null hypothesis for those parameters with small enough standard errors if those smaller standard errors were still ultimately the result of chance. Common correction methods for such assurance include but are not limited to the Bonferroni correction. This post discusses those correction methods as well as an alternative that I recently thought of. Follow the jump to see everything else, because even the introduction, which is meant to be a brief introduction to statistical models, is long enough that the jump would otherwise be too far below & would break the flow of this post for a reader.

Book Review: "The Book of Strange but True Science"

It had been a while since I had read a book, so I recently read the book The Book of Strange but True Science, which does not have any named authors; my family gave this to me as a birthday gift last year. It is a fun jaunt through scientific phenomena, technological & engineering innovations, and the histories of discoveries of those things, covering most major topics in STEM fields and with each vignette being less than 10 pages.

The book is written at probably a middle school reading level (from my time, though with the decline in reading proficiency among school students across the country, perhaps this is more like a high school reading level), and its perspective is clearly American. All of the vignettes were fairly superficial, and most of them felt familiar to me from school. Thus, I might have liked this more in middle school or high school, but at this point in my life, it feels too basic for me. That said, I would recommend it for any lay reader who could be interested in STEM topics.

Differences in Weather Fluctuations in Different Latitude Regimes

Recently, I learned more about weather & climate, particularly at higher elevations in the atmosphere; I used to feel a little intimidated to think about those things, so essentially all of my posts on this blog explaining features of different climates only used surface-level weather phenomena to the greatest extent possible (and arguably sometimes to a greater extent than was appropriate or justifiable). Although the insights that I gained from such learning are not especially groundbreaking compared to my previous two posts about wind divergence or seasonal changes to subtropical ridges over oceans, I feel like I have rounded out my basic understanding of weather & climate, and I wish to share that here. These explanations make clear why there are larger weather from day to day at middle latitudes than closer to the equator or poles as well as why certain analogies, like between middle latitudes at west coasts & tropical latitudes at east coasts, have limits. 

The sources that I used are many relevant pages from Wikipedia, the Columbia University interactive maps of mean monthly wind velocities, and these meteorology lecture notes from the University of Arizona. Again, I am not a trained climatologist or meteorologist; I can't guarantee that this information is accurate, and I can only say that my intuitions seem through my limited understanding to align with superficial aspects of more detailed explanations. Follow the jump to see more.

Differences in Strengths of Subtropical Ridges Over Oceans

Earlier this year, I wrote a post about how subtleties in the convergence and divergence of large-scale surface winds can explain many features of local climates. However, as I thought about it more, I realized that I still wasn't satisfied with my understanding of why the seasonal variation in strength of a subtropical ridge over an ocean depends on the ocean in consideration. Specifically, the subtropical ridges over the Pacific, Atlantic, and Indian Oceans in the southern hemisphere as well as over the Atlantic Ocean in the northern hemisphere are stronger (higher pressure) during those respective hemispheres' winter halves of the year, but the subtropical ridge over the Pacific Ocean in the northern hemisphere is stronger during the northern hemisphere's summer half of the year.

Having looked more at the Columbia University interactive maps of mean monthly wind velocities, I am reasonably more confident that I can explain these & related phenomena mostly through surface wind dynamics, though the explanations aren't complete. Again, I am not a trained climatologist or meteorologist; I can't guarantee that this information is accurate, and I can only say that my intuitions seem through my limited understanding to align with superficial aspects of more detailed explanations. Follow the jump to see these explanations.

Subtleties of Wind Patterns Affecting Precipitation

Last year, I wrote a long post on this blog giving the most general intuitive explanations possible for the existence of different climate types, based on different configurations of land & ocean at different latitudes, and used that to explain broad & subtle features of actual climates of most locations. As I alluded to in that post, I had a lingering question of why, at tropical latitudes, there are so many east & poleward coasts that have dry seasons despite those coasts getting ordinary easterly (sometimes with a poleward originating component too) tradewinds throughout the year largely perpendicular to the coast. My confusion is because at those latitudes, the water & land temperatures are warm enough even in the winter half of the year to suggest that humid air from over the ocean could unstably rise above air over land & lead to precipitation. Examples include but are not limited to the north (poleward)/east coast of Central America, the north (poleward) & east coasts of islands in the Caribbean, some parts of the coast of Brazil, the east coast of the southern part of India, and the east coast of the northeastern part of the mainland of Australia. I also had a question about why the north coast of Egypt did not get precipitation in the summer half of the year despite getting northerly onshore winds from over the Mediterranean Sea, which is warm enough that despite the air over land becoming considerably hotter then, humid air from over the Mediterranean Sea could in principle rise above dry air over land, leading to instability and therefore precipitation. Additionally, I had a question about why the subtropical ridge over each ocean (more prominently over the Atlantic & Pacific Oceans in the northern hemisphere) is more poleward along the eastern edge of the ocean even though the western edge has warmer currents (suggesting lower pressure along the western edge than along the eastern edge along the same latitudes).

I could not think of satisfactory answers until very recently. Ironically, although that linked post from last year referred to concepts beyond surface-level wind patterns & air pressures, these answers depend mostly on surface-level wind patterns along with the knowledge of what different surface-level wind patterns imply for vertical air flow. The sources that I used are many relevant pages from Wikipedia and the Columbia University interactive maps of mean monthly wind velocities; unfortunately, the latter resource will be shut down in 2026 April due to funding difficulties. Again, I am not a trained climatologist or meteorologist; I can't guarantee that this information is accurate, and I can only say that my intuitions seem through my limited understanding to align with superficial aspects of more detailed explanations. Follow the jump to see these answers.