geo

Factors Influencing Temperature

The climate of a region is affected by three main factors:

• Ocean currents

• Latitude

• Elevation

Latitude

• Latitude is expressed as a degree north or south of the equator.

• The equator is 0° N or S.

• The larger the degree of latitude, the further away from the equator the place is.

• The equator is hot, and the further one moves away from it, north or south, towards the poles, the colder it becomes.

Reasons Why the Equator Is Hot

• The equator receives direct sunlight.

• Few sunrays are reflected off the Earth.

• The sunrays heat a smaller area at the equator.

• The sunrays travel through less atmosphere at the equator.

Reasons Why the Poles Are Cold

• The poles receive oblique (not direct) sunlight.

• Many sunrays are reflected off the Earth.

• The sunrays heat a larger area at the poles.

• The sunrays travel through more atmosphere at the poles.

Altitude

• The temperature in the atmosphere decreases by 6.5°C per 1000 meters. This is expressed as \frac{6.5^\circ C}{1000m}.

• The Earth is heated by shortwave radiation from the Sun.

• This heat is reflected back through the atmosphere as longwave radiation.

• Water vapor and carbon dioxide trap this radiation.

• The lower parts of the atmosphere are hottest due to larger concentrations of these gases, and it cools down as altitude increases.

The Greenhouse Effect

• Incoming solar radiation is either reflected by clouds or back-scattered by air.

• Some solar radiation is absorbed by water vapor and gases.

• The Earth absorbs some solar radiation.

• Net longwave radiation is reflected by the surface.

• Outgoing longwave radiation is emitted by clouds, absorbed by clouds, water vapor, and gases, and emitted by water vapor and gases.

Distance From the Sea: Continental vs. Maritime Climates

• Land and sea heat very differently.

Continental Climate (Far From the Sea)

• During the day, land heats up quickly because only the first 15cm of soil is heated.

• Land surface temperatures can reach up to 65°C during the day.

• This hot land surface heats up the air above it, causing hot daytime temperatures.

• At night, land loses its temperature quickly.

• Early morning temperatures inland are very cold (especially in winter) because the Earth has lost all its heat by 3 am.

• Inland places have hot summer and daytime temperatures and colder nighttime and winter temperatures.

• The daily temperature range is calculated by finding the difference between the maximum and minimum temperatures.

• Range = Max\,temperature - Min\,temperature

• For example: Range = 32°C - 15°C = 17°C

Maritime Climate (Near to the Sea)

• Water is transparent, so sunrays penetrate deep into the water, warming it slowly.

• Water warms more slowly and never reaches more than ± 25°C.

• The sea has a cooling effect on coastal towns during the day.

• At night, water releases its heat more slowly, continuing all through the night.

• The sea has a warming effect on coastal towns at night.

• Coastal towns do not get very hot during the day or in summer and do not get very cold during the night or in winter.

• The ocean moderates temperature.

Ocean Currents

• Warm ocean currents flow from the equator, bringing their heat, and have a warming effect on the coastlines they pass.

• Warm currents generally flow along the east coasts of continents.

• Cold ocean currents flow from the poles and have a cooling effect on the coastlines they pass.

• Cold ocean currents generally flow on the west coasts of continents.

Aspect

• The sun shines more directly on the tropics (23.5° N to 23.5° S).

• From any country in the southern hemisphere, the sun does not appear directly overhead at 12h00 but slightly towards the north.

• When there is a mountain range that runs east-west, there will be a noticeable temperature difference between north-facing and south-facing slopes.

• In the southern hemisphere, north-facing slopes receive more direct sunlight than south-facing slopes, making rooms and houses that face north more sought after.

• Sun-facing slopes are warmer and drier with varied soil fauna and organic matter incorporation.

• Shaded slopes are colder and wetter with restricted soil fauna and surface accumulation of acid organic matter.

• Runoff is less on sunny slopes with increased soil moisture in hollows, while runoff is normal on shaded slopes.

Wind

• Wind will lower the temperature experienced outside.

• This is often referred to as the "wind chill factor."

• When wind blows, it encourages evaporation, which is a cooling process, thus the temperature will drop.