Variable Weather & Changing Climate KQ1 - Why Do Different Places Experience Different Weather and Climate?

What is the difference?

Weather refers to the condition of the atmosphere at a particular place and time.

Climate is the average condition of the atmosphere of a specific place over a long period of time, usually over 30 years.

We can describe weather with the six following elements

1. Temperature - degree of hotness or coldness of a place
2. Relative Humidity - amount of water vapour the air can hold at a given temperature
3. Clouds - visible masses of water droplets or ice crystals which are suspended in the atmosphere
4. Rainfall - precipitation or water that falls from the atmosphere down to the surface of the earth
5. Air Pressure - force exerted on an unit area of earth's surface by a column of air
6. Wind - movement of air from an area of high to low pressure

Temperature is determined by the amount of energy from the sun which reaches the earth. Most of the sun's energy travels through the atmosphere and is absorbed by the earth's surface, causing it warm up and heats up the atmosphere (Refer to the diagram below)

Temperature is regularly measured and recorded it is measured in degrees Celsius (°C) or degree Fahrenheit (°F). It is measured using a thermometer. Usually, we usually record temperatures because it allows us to determine weather patterns of a place. 

We can do this by calculating the

• Mean Daily Temperature - Sum of hourly temperatures divided by 24 hours
• Mean Monthly Temperature - Average daily temperatures recorded in a month
• Mean Annual Temperature - Average temperature recorded in a year
• Temperature Range - Difference between maximum and minimum temperature
• Diurnal Temperature Range - Difference between maximum and minimum temperatures in a day
• Annual Temperature Range - Difference between maximum and minimum mean monthly temperatures recorded in a year

In the study of weather, anything above 20°C is considered high temperature and low temperature as below 10°C.

Why Different Places Experience Different Temperatures?

Temperatures vary across the earth. Some places are colder while others are warmer.

Factors that cause variations include

• Latitude - distance of any point of on earth measured north or south from the Equator
• Altitude - height of a place in relation to the sea level
• Distance from the Sea - how near or far a place is from the sea which results in a difference between the rate of heating and cooling
• Cloud Cover - extent of the sky covered by clouds

*I have covered the first two factors in the previous posts, click on it to redirect the page to the post :)

Distance from the Sea

Places near the sea experience smaller annual temperature range due to the Maritime Effect - It is the effect that large ocean bodies have on the climate of coastal areas. The sea heats up and cools down slower than land, causing it to have a smaller annual temperature range. 

During summer, the air over the sea is cooler than the air over the land. The cooler air over the sea helps lower the temperatures of coastal areas, therefore making the climate of the coastal places cooler than areas further inland.

Coastal areas experience cooler summers and warmer winters as a result of the maritime effect. 

Continental Effect on the other hand, refers to the effect that continental surfaces have on the climate of inland areas, Land heats up and cools down quicker than the sea. Therefore resulting in larger annual temperature range, and inland areas experiencing warmer summers and cooler winters 

Cloud Cover

The amount of cloud cover influences the temperatures on the earth's surface in the day and night. More cloud cover will result in a smaller difference between day and night temperatures, while less cloud cover will result in a larger difference between day and night temperatures - diurnal range. 

In the day, cloud cover also reduces the amount of direct sunlight an area receives, resulting in cooling. While at night, it traps longwave radiation radiated from the earth's surface which results in warming.