WC_Review of Earth Science Lesson
Let's talk about Earth's journey around the sun and how it impacts the weather and climate, something you probably have seen earlier in your studies, but a refresher is always great!
Earth’s Rotation
First off, Earth's orbit around the sun is almost a perfect circle, but not quite. We're about 150 million kilometers away from the sun on average. The orbit's a bit squished, so there are times we're closer to the sun and times we're a bit further away. This squishiness is called 'eccentricity,' and for Earth, it's pretty small (0.0168). It means we're about 3.4% further from the sun at our farthest point (called aphelion) compared to our closest point (perihelion). Neat, right? Perihelion happens every January, and it shifts slightly each year.
Earth’s Tilt and Seasons
Now, let's talk about the tilt. Earth is tilted at 23.45 degrees, which is why we have seasons. This tilt means that during certain times of the year, different parts of Earth get more direct sunlight. When it's directly above the Equator (around March 21 and September 21), we have the equinoxes - days when day and night are roughly equal.
The Tropics of Cancer and Capricorn, sitting at 23.45° North and South, mark special lines on Earth. Inside these lines is where the sun can be directly overhead at noon at least once a year.
The cool thing is, because of Earth's tilt and orbit shape, the most sunlight (solar insolation) spread over Earth's surface actually happens in early January. But, the strongest sunlight hitting one specific spot outside the tropics is around June 21 in the Northern Hemisphere and around December 21 in the Southern Hemisphere. These are the summer solstices for each hemisphere.
This is also how we get our seasons! Check it out in the video below
So, what does this look like in the Solar System? Use the simulation below to observe how the Sun’s Rays change on the Earth’s surface based on its location in orbit.
How Does Heat Capacity Apply to Weather?
Absolutely, let's delve into how the heat capacity of land and water impacts Earth's weather and climate. It's a fascinating aspect of our planet's natural system.
Heat capacity is basically how much heat something can absorb before its temperature changes. Water, like our oceans, has a high heat capacity, meaning it can absorb a lot of heat without a big change in temperature. Land, on the other hand, has a lower heat capacity, so it heats up and cools down more quickly. This difference plays a huge role in our climate. For instance, during the day, land gets hotter faster than the ocean. This creates air pressure differences, leading to winds. At night, the land cools down quickly, which can reverse these wind patterns.
These differing heat capacities also create a kind of climate regulator for our planet, especially in coastal areas. For example, in summer, the land heats up faster than the ocean, so the air above the land gets warmer and rises, pulling in cooler air from over the ocean - this is why coastal areas often have cooler summers and milder winters compared to inland areas. In winter, the ocean loses heat more slowly than the land. So, coastal areas can be warmer compared to inland areas during colder months. This moderating effect of large water bodies on climate is called 'maritime influence.' It's a key reason why islands and coastal regions often have less extreme temperature variations than inland areas.
The main point of this lesson is to understand how Earth's orbit, its slight eccentricity, and the 23.45-degree axial tilt contribute to the seasonal changes and distribution of sunlight across the planet. These factors, combined with the differing heat capacities of land and water, significantly influence global weather patterns and climate conditions.
UP NEXT: Oceanic & Atmospheric Circulation
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