Climate Topic 1: Weather and Climate

It is the state of the atmosphere at a specific place and time

It is the average state of the atmosphere at a particular place over a long period of time, usually 25 years or more.

Tropical Equatorial, Tropical Monsoon & Cool Temperate climate

Located between 10°N and 10°S of the equator. High annual temperatures of 27°C all year round. Small annual temperature range of 2 to 3°C. High total annual precipitation of more than 2000mm falling evenly throughout the year

Located between 5°N and 30°N and 5°S and 30°S of the equator. High mean annual temperatures of 25°C all year round. Small annual temperature range of 3 to 4°C. High total annual precipitation of 1500mm with distinct wet and dry seasons

Located between 45°N and 60°N and 45°S and 60°S of the equator. Four distinct seasons. Moderate mean annual temp of 10°C. Large annual temperature range of 10 to 15°C. Low total annual precipitation of 75 to 200mm falling evenly throughout the year

The distance of a place north and south of an equator from 0° to 90° North or South. Latitude lines are horizontal, parallel to the equator

23.5°N and 23.5°S respectively

66.5°N and 66.5°S respectively

$\frac{Sum \space of \space mean \space monthly \space temperatures}{12}$

Maximum mean monthly temperature - minimum mean monthly temperature

5-14°C

10-19°C

250-999mm

Climate-related processes or phenomena, such as extreme weather events that may cause loss of life or injury, property damage, social and economic disruption or environmental degredation

Rare and severe events such as heat waves, droughts, floods, cyclones and wildfires

Consist of natural processes that occur on Earth and all living and non-living things that are found naturally vs consist of human-led processes and the interconnected human activities

Ecosystem and Agriculture respectively

It is a natural process by which the greenhouse gases in the Earth's atmosphere trap longwave radiation, and which makes Earth liveable

Carbon dioxide, methane, nitrous oxide and water vapour

The processs in which heat that is given out by the sun reaches the earth

Heat that is re-emitted from the Earth's surface to the atmosphere

Most of it is absorbed by the earth's surface while some of it is absorbed and reflected by clouds

Most of it escapes from earth into space, but some of it is absorbed by greenhouse gases and is re-emitted in the atmosphere keeping the earth warm

Largely due to earth's rotation on its own axis. In the day, the side of the earth facing the sun receives solar radiation and hence experiences higher temperatures compared to the other side that does not receive solar radiation

The sun is directly overhead, and due to earth's spherical shape, solar radiation is spread over a smaller area making it more concentrated and thus makes it have the highest temperatures ranging from 31 to 33°C

The sun isn't directly overhead, and due to earth's spherical shape, solar radiation is spread over a larger area making it less concentrated and thus makes it have lower temperatures ranging from 25 to 31°C

In September, northern experiences autumn and southern experiences spring and in march, northern experiences spring and southern experiences autumn due to the fact that neither hemispheres lean towards the sun, they therefore experience moderate temperatures

Winter and Summer as the northern hemisphere leans away from the sun, receiving less direct solar radiation therefore having lower temperatures while the southern hemisphere leans towards the sun, receiving more direct solar radiation therefore having higher temperatures

Summer and Winter as the southern hemisphere leans away from the sun, receiving less direct solar radiation therefore having lower temperatures while the northern hemisphere leans towards the sun, receiving more direct solar radiation therefore having higher temperatures

23.5°

The solar angle is higher meaning solar radiation is concentrated over a smaller surface area

The solar angle is lower meaning solar radiation is concentrated over a larger surface area

The air is denser, meaning air pressure is higher. This means that there are more air molecules as gravity pulls down most of them to the surface resulting in a higher ability to absorb and radiate heat

The air is less dense, meaning air pressure is lower. This means that there are less air molecules as gravity pulls down most of them to the surface resulting in a lower ability to absorb and radiate heat

Water, Forest, Grass, Ice (old snow), Clouds and ice (fresh snow)

Urban area experiences much warmer temperatures than surrounding rural areas, forming island of heat as tarmac roads absorb and radiate a lot of solar radiation and glass covered sky scrapers reflect a lot of solar radiation and sunlight into the ground

The land heats up and cools down faster than water bodies

In coastal areas during winter, the sea remains warmer than the land as the sea loses heat slowly. Hence, the warmer air above the sea warms the coastal areas, giving warmer winters. During summer, the sea remains cooler than land as it gains heat slower. Hence, the cooler air above the sea cools the coastal areas giving cooler summers

In inland areas during winter, the land is cooler than the sea as the land loses heat quickly. Hence, the cooler air above the land cools the inland areas, giving cooler winters. During summer, the land is warmer than the sea as it gains heat faster. Hence, the warmer air above the land heats up the inland areas giving warmer summers

The temperature where the air becomes saturated with water vapour. As such, below this temperature, condensation occurs

Water enters atmosphere through evapotranspiration & as water vapour rises —> cools and condenses into tiny water droplets at dew point temperature and clouds are formed. When the water droplets become big and heavy enough, they fall to the ground as precipitation (eg water and snow)

Water on the ground then infiltrates the top layer of soil and rock (subsurface soil and rock)

Below the earth's surface, water moves horizontally above the impermeable rock (rock which does not allow water to pass through)

Sandy (larger pores, more permeable) & silt/clayey soil (smaller pores, less permeable)

More ground surfaces are covered in concrete which has tiny pores making them less permeable and have lower infilration rates and groundwater flows. There are also smoother ground surfaces like roads and footpaths with fewer obstructions and less friction

Roots of plants loosen soil creating larger pores and more space for water to pass through resulting in faster infiltration rates and groundwater flows. Also, vegetated areas have rougher ground surfaces and more barriers to flow (eg stems / roots of plants) resulting in greater friction

Steeper slopes have higher speeds of surface runoff compared to gentler ones due to the force of gravity acting on the water

$\frac{Actual \space amount \space of \space water \space vapour \space in \space the \space air \space (g/m^3)}{Maximum \space amount \space of \space water \space the \space air \space can \space hold \space (g/m^3)} \times 100%$

Decrease as the amount of water vapour the air can hold increases

When relative humidity exceeds 100% and if a condensation nuclei is present

As the air rises after evaporation, it cools which decreases amount of water vapour it can hold. At dew point temperature, the air cools and condenses tiny water droplets on the condensation nuclei

dust, salt crystals, soot, pollen, bacteria and ash from volcanoes. These provide surfaces for water to condense on

Water droplets in the clouds, collide and coalesce, becoming bigger and heavier and when large (> 0.5mm) and heavy enough, they fall to earth as raindrops.

Convectional rain forms when the sun heats the ground, warming the air above it until it rises, cools, and condenses into raindrops. In contrast, relief (or orographic) rain occurs when moist, onshore winds are forced to rise over a mountain range.

It is the horizontal movement of air across the Earth’s surface

Due to the unequal distribution of air temperature, which results in an uneven distribution of pressure

The closer spaced the isobars in a diagram are

Lower means less difference in pressure between 2 areas while higher means more difference leading to slower and faster wind speeds respectively

Strength of pressure gradient (Lower is slower, higher is faster) and friction (uneven relief and rough surfaces like valleys and mountains)

Due to the unequal distribution of air temperatures. So, air moves from high pressure to low pressure zones

Northeast Monsoon & Southwest Monsoon

From Oct to Feb, the northern & southern hemispheres experience winter & summer respectively. Air thus moves from Central Asia (higher pressure) towards Australia (lower pressure). When they reach India, they are deflected right due to the coriolis effect.

From Jun to Sep, the northern & southern hemispheres experience summer & winter respectively. Air thus moves from Austrailia (higher pressure) towards Central Asia (lower pressure). When they cross into the northern hemisphere, they are deflected to the right