The first step in understanding how does latitude affect precipitation is to define both latitude and precipitation independently.
The term “precipitation” describes all forms of water that come from the sky and land.
Latitude is the distance north or south of the Equator, as expressed in angular degrees from 0° at the Equator to 90°.
Precipitation decreases as one moves away from the Equator toward the poles. Because temperature affects the amount of moisture air can hold, the rate at which precipitation falls typically reduces with the increase in latitude, with lower latitudes usually experiencing more precipitation.
Suitable Conditions for Precipitation
Here are some of the ideal conditions for precipitation:
- The atmosphere must be moist enough.
- There must be a presence of condensation nuclei.
- Weather conditions must be ideal for water vapor to condense into water.
- Condensation products must reach the Earth.
Rainfall, snowfall, hail, frost, and dew are examples of precipitation.
Fact: The amount of precipitation, combined with the soil and vegetation types in a location, can determine which plants and animals can live there.
Understanding the Effects of Latitudes
Numerous changes take place in different locations owing to their difference in latitudes.
It’s safe to say that the weather or climatic conditions you’ll experience in the tropics are very much different from what you’ll experience in the Polar Regions.
Here is a list of primary Earth’s phenomena affected by latitudes:
- Earth’s Curvature
- Local Weather
Types of Latitudes
There are different kinds of latitude: geocentric, astronomical, and geodetic. Geocentric latitude is the same as astronomical latitude, except it uses the Equator instead of the Greenwich prime meridian.
Geodetic latitudes are calculated from a reference ellipsoid instead of from astronomical observations.
Geodetic latitude is about 1/10th of a degree higher than astronomical latitude.
Latitude and Earth’s Curvature
Because the Earth is not a perfect sphere, its curvature flattens out as it approaches its poles.
Geographic latitude is the arc subtended by the equatorial plane and the standard inch-by-inch line drawn on Earth at any given point.
Uneven Earth Heating due to Earth’s Curvature
The sun’s rays are more direct at the center of the Earth than at the poles.
This is because the Earth’s tilt tends to maximize sunlight at the Equator, where the Earth’s spin axis intersects with its orbital plane.
Because of this tilt, regions around the Earth’s middle are consistently hotter than other parts of the planet. When air is warm, it holds more moisture, condenses to clouds, and falls as rain.
Hot air rises. This movement creates low-pressure areas that pull in air from other areas, creating wind. The circulation of air and resulting heating and cooling causes the Earth’s climate and weather patterns.
Fact: This explains why areas around the Equator generally receive more precipitation.
Latitudes and Temperature
Scientists have found that temperature is inversely related to latitude, or how far away from the Equator.
Generally, around the world, temperature increases towards the Equator and decreases towards the poles.
Latitudes and Temperature decreasing with increasing latitude is called a negative gradient; temperature increasing with increasing latitude is called a positive gradient.
Temperature and Precipitation
So how does latitude affect tropical precipitation? Because warmer air can hold more moisture, evaporation will increase as the temperature increases. This means that precipitation will also increase.
Increased temperatures may lead to more evapotranspiration in plants, leading to more precipitation, especially in heavily forested areas within the tropics.
It’s worth noting that precipitation may increase, but water available for drinking, irrigation, and industry will not necessarily increase.
Note: Air temperature and precipitation can have wide-ranging effects on natural processes, and wide-ranging datasets are foundational for analyzing drought and climate change.
Latitudes and Climate
The Earth’s climatic classifications range from dry, tropical, mild, continental, and polar. Latitudes have the most significant impact on climate in various ways.
At high latitudes, the rays of the sun are not direct compared to the equatorial regions. As areas move away from the Equator, their temperatures drop.
The higher an area is above sea level, the colder it is. The polar regions generally receive little to no sunlight.
A lot of the arctic and Antarctic regions are covered with snow and ice, which are known to be major reflectors of sun’s light.
Equatorial vs. Arctic Climatic Conditions
The equatorial region on Earth receives an abundance of sun’s heat electromagnetically radiated from space, so the temperature remains reasonably constant throughout the year.
Climate data indicates that the average daytime and nighttime temperatures range from 54.5 to 57.7 degrees Fahrenheit (12.5 to about 14 degrees Celsius).
Temperature variations are more extreme at the poles than in the equatorial regions. At the North Pole, the temperature can rise above freezing during summer and fall below -40 degrees Celsius during winter.
In contrast, at the South Pole, the temperature reaches as high as 28.2 degrees Celsius in summer and plummets to -76 degrees Celsius in winter.
Climate and Precipitation
People who believe the Earth is flat have a hard time explaining global climate variations. But people who accept that the Earth is a sphere can explain them easily.
Since the sun’s rays are least direct in higher latitude areas, they are likely to experience extreme winters characterized by precipitation like snow and blizzards.
For example, most European countries and much of the US and Canada experience freezing winters.
Latitude and Seasons
The Poles and the Equator have uniform temperatures, being impacted only by day/night cycles.
Understanding how does latitude affect precipitation means we have to delve into how seasons vary, with the changes in temperature and humidity in the poles and equatorial regions.
Over a year, the sun’s angle in a location changes enough to create significant cyclic variations in daily and nightly temperatures that we call seasons.
Seasons and Precipitation
The characteristics of a season depend upon how far or near they are from the Equator, Latitude 0. The further north or south, the more extreme the seasons tend to be.
For example, summers in USA or Australia are characterized by very little to no precipitation due to dry conditions. It’s not uncommon to witness many forest fires in the summer months due to the dry conditions.
Fact: In higher latitudes (such as northern North America), the days tend to be longer because the sun takes longer to rise and set.
Latitude and Local Weather
Since temperature changes with the changes in latitude, the weather is also bound to change.
A place’s latitude is the angular distance of that place north or south of the Equator.
Closer to the Equator, a place will be closer to the Earth’s the Equator and warmer. Closer to the poles, a place is located farther away from the Equator and, therefore, colder.
Weather and Precipitation
Cold weather means the air can’t hold as much water vapor as warm. This explains relatively more minor rainfall in colder areas located further away from the Equator.
It’s also important to note that factors other than latitude can affect local weather and precipitation.
For example, mountainous regions often experience more extreme weather than other areas because they act as a barrier to air movements and moisture.
For example, winds hitting a mountain range might not be able to move past it, leaving the side of the mountain that faces the wind relatively dry.
Read Next: What are the Four Main Types of Precipitation?
When elucidating how does latitude affect precipitation, one must delve deep into various factors at play like seasons, weather, climate, and so on.
This is because latitude predominantly affects temperature, which affects all the factors affecting precipitation.
It’s also worth noting other conditions that affect precipitation regardless of the latitude.
These are the distance from the sea, ocean currents, the direction of the prevailing winds, and land terrain.