Many people have noticed that snow is melting at one speed not everywhere. While outside the city it can remain in shaded places even at the end of spring, in the city its melting is much faster.
In urban conditions, the average latitude of snow may not be by the end of March, but outside the city such a fast onset of spring is rarely observed. Why is snow melting at different rates, and where does this interval come from?
The difference between urban and suburban conditions
In order to find the difference, you must first compare the urban and suburban conditions. It is worth noting that the cities are always warmer. There are many reasons for this, and it makes sense to start with the fact that every city is constantly under a cloud of smog. People living in large settlements are used to not noticing this fact, but in practice it is there.
Interesting fact: if you decide to watch the night starry sky, in urban conditions it will seem unclear - even if there are no bright lights nearby. This manifestation is the result of smog, because far from settlements, the sky in fine weather is almost always clear.
Smog and carbon monoxide create a greenhouse effect, retain heat, and the smoke from numerous factory chimneys is warm in itself. But that's not all. Heat and exhaust gases that create the same effect are emitted by cars, which are more and more from year to year. Creates them and urban transport.
Heat is generated by heat supply lines, residential buildings, and lighting equipment. All this taken together becomes a significant reason for additional heating of the air over the city. If the city has a temperature of -25, the city can be only -20, and there will be no strong wind due to the abundance of buildings. But the temperature factor is not at all decisive in this matter.
The color of snow and its nuances
The white color of the snow has a reflective property. Consequently, most of the sunlight falling on it is reflected without heating the surface itself. In nature, snow, as a rule, has a pure white tint, because they have nothing to pollute. But in the city pure white snow is a luxury. Most snow masses in settlements are subject to intense pollution. Smoke, soot, dust and other pollutants settle on it in the form of the smallest particles, and remain until the final stages of melting.
Black color and any dark shades contribute to intensive heating of the surface, which significantly accelerates the process of melting. Every spring day with sunrise, the dark surface of the dirty snow heats up and begins to melt more intensively than the pure white, reflecting light - from there the difference in the speed of melting arises. Concrete, asphalt surfaces with a dark color are also heated - and they also actively contribute to melting.
Environmental Standards and Global Warming
Today, in most developed countries, strict environmental standards are introduced, which apply not only to all enterprises, but also to every ordinary motorist and citizen as a whole.They are aimed at reducing greenhouse gas emissions into the atmosphere, which should reduce the rate of warming and save the living world of the planet.
According to scientists, these measures will help to cope with the rate of increase in temperature indicators throughout the globe, with a problem that is actually observed in practice. However, it is still not proven whether the temperature inversion is anthropogenic in nature, or whether it is itself a whim of nature. It is worth recalling that the temperature indicators on our planet are very variable, and the norm varies greatly even from one century to another.
But in any case, compliance with environmental standards and minimizing harmful emissions can somewhat offset the temperature difference between cities and the environment. Will the snow in cities become cleaner, whiter, and therefore, will it better reflect light and lie longer? Will it be better or worse for the taste of each individual person? This aspect is unknown, but in any case it will be more natural, closer to the natural norm.
