Perigee & Apogee: How Earth's Orbit Impacts Summer Temperatures

In summary, the perigee and apogee of Earth's orbit relative to the seasons affect the temperature of our summers. However, the orbit is slightly eccentric, and indeed it plays some role. The perihelion occurs at beginning of January, and as Earth is slightly closer to Sun than a mean distance, the winters on northern hemisphere are bit warmer than winters on southern hemisphere (aphelion occurs in July). Similarly, the summers are bit colder on northern hemisphere.
  • #1
philip porhammer
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does the Perigee and Apogee of the Earth's orbit relative to the seasons affect the temperature of our summers?
 
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  • #2
philip porhammer said:
does the Perigee and Apogee of the Earth's orbit relative to the seasons affect the temperature of our summers?
What's your conclusion, given that the sun is approximately constant in its radiation output? Have you considered northern and southern hemispheres?
 
  • #3
You probably mean perihelion and aphelion instead of perigee and apogee when we talk about Earth orbiting Sun.
The reason why we have seasons on Earth is due to the fact that axis of Earth's rotation is not perpendicular to the orbital plane, it is tilted by about 23 degrees. As Earth orbits Sun, one of the hemispheres is getting more sunlight than the other, except equinoxes, of course.
However, the orbit is slightly eccentric, and indeed it plays some role. Perihelion occurs at beginning of January, and as Earth is slightly closer to Sun than a mean distance, the winters on northern hemisphere are bit warmer than winters on southern hemisphere (aphelion occurs in July). Similarly, the summers are bit colder on northern hemisphere.
 
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  • #4
Interesting question. From my calculations, if the Earth were not tilted, and had no atmosphere, the variation in temperature would be ≈4.5°C (≈8°F).

Wiki lists:
a. Earth's tilt
b. Higher concentration of land masses in the northern vs southern hemispheres​
as two reasons this is hard to figure out.

"...summers are 2.3 °C (4 °F) warmer in the northern hemisphere than in the southern hemisphere under similar conditions."

Which is backwards, if temperature were based on apsides.
 
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  • #5
You are right! I made it too simple in my previous post, I didn't consider the difference in surface of the hemispheres. What I wrote would be the case if the Earth's surface is homogeneous.
The surface of the southern hemisphere is covered by more ocean and less land comparing to northern hemisphere. That influences how is the heat absorbed and transported over the surface. I found this link interesting.

One can learn something new every day!
 
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lomidrevo said:
Perihelion occurs at beginning of January, and as Earth is slightly closer to Sun than a mean distance, the winters on northern hemisphere are bit warmer than winters on southern hemisphere (aphelion occurs in July).
No, that is very incorrect and you only need to look at the data to see that.
The southern hemispheres have VERY mild winters compared to the northern hemisphere.
We don't get the massive snowfalls, ice storms, rivers freezing over etc etc

OmCheeto said:
"...summers are 2.3 °C (4 °F) warmer in the northern hemisphere than in the southern hemisphere under similar conditions."

yeah ... under similar conditions, which of course they are not :wink:

Dave
 
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  • #7
davenn said:
No, that is very incorrect and you only need to look at the data to see that.
Yes, I thought I made it clear in my post #5, that I admit I was wrong in my first post. Although the difference of solar irradiance between perihelion and aphelion is almost 7%, the Earth's climate system (including distribution of land and ocean) has a more significant influence on the surface temperatures.

davenn said:
The southern hemispheres have VERY mild winters compared to the northern hemisphere.
We don't get the massive snowfalls, ice storms, rivers freezing over etc etc
If you compare the mean temperatures at comparable (opposite) latitudes (e.g Sydney and Los Angeles), the difference is not very big. Daily mean in Sydney 13 °C (in July) vs. 14.4 °C in LA (January) could even suggest colder winter in Sydney. Of course, this is very simplified comparison, as we do not take into account any effects due to regional climate conditions (we could also try to compare Europe and Patagonia). I just want to point out that differences might not be so big as you suggest.
 
  • #8
Another variable is the oceanic heat sinc and its variation of currents.
 

1. What is perigee and apogee?

Perigee and apogee refer to the closest and farthest points in Earth's orbit around the sun, respectively. Perigee occurs when Earth is closest to the sun, while apogee occurs when Earth is farthest from the sun.

2. How do perigee and apogee impact summer temperatures?

When Earth is at perigee, it is closer to the sun and therefore receives more direct sunlight. This can lead to warmer summer temperatures. Conversely, when Earth is at apogee, it is farther from the sun and receives less direct sunlight, resulting in cooler summer temperatures.

3. How often do perigee and apogee occur?

Perigee and apogee occur approximately every 27.5 days, which is the time it takes for Earth to complete one orbit around the sun.

4. Are perigee and apogee the only factors that impact summer temperatures?

No, there are many other factors that can impact summer temperatures, such as the tilt of Earth's axis, atmospheric conditions, and ocean currents.

5. How do scientists measure perigee and apogee?

Scientists use a variety of methods to measure perigee and apogee, including satellite observations, radar measurements, and mathematical calculations based on the laws of gravity and motion.

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