1/ Orographic Precipitation:
-Orographic precipitation takes place at mountainous places.
-Some processes take place during Orographic Precipitation: (in order)
-Evaporation:
- of the ocean water creating moist air over ocean surface.
- of ice crystals and air moisture in the cloud when it moves down the leeward slope, creating hot and dry air region at the base of the mountain.
-Adiabatic cooling: (Refer to Chelsia's post for definition)
- Condensation of the water vapour when air rises on the windward slope since air is cooled adiabatically. (Condensation is the change of the physical state of matter from gaseous phase into liquid phase)
- Precipitation of water vapour occuring when air continues to rise higher on the windward slope. Precipitation will start to fall to the surface, creating a rain shadow.
- Evaporation of the moisture in clouds when the air travels down the slope of the mountain makes air hot and dry. Hence, dry and hot deserts are observed at the end of the leeward slope.
2/ Frontal Precipitation:
Summary of mechanism of Frontal Precipitation
- Warm front: warm air advances towards cold air -> warm air rises and coolds adiabatically -> condensation -> rain
- Cold Front: heavier cold air advances and pushes beneath warm air -> warm air is forced upwards and cools adiabatically -> condensation -> rain
Differences between warm front and cold front:
- By definition,
o Warm front is the boundary between cold air and warmer air that's replacing the cold air
o Cold front is the boundary between warm air and colder air that's replacing the warm air.
- A cold front is associated with colder weather and a warm front is associated with warmer weather. Cold front is usually found at a temperature drop's leading edge. Meanwhile, warm front is usually found at a homogenous warm air mass's leading edge.
- Cold fronts can move up to twice as fast as warm fronts can, since cold air is denser and harder to be removed from the earth’s surface than warm air. As a result, cold fronts can produce sharper changes in weather than warm fronts.
- Due to the difference in mechanism, different types of weather are created:
Weather conditions associated with a cold front.
Weather Phenomenon | Prior to the Passing of the Front | Contact with the Front | After the Passing of the Front |
Temperature | Warm | Cooling suddenly | Cold and getting colder |
Atmospheric Pressure | Decreasing steadily | Leveling off then increasing | Increasing steadily |
Winds | South to southeast | Variable and gusty | West to northwest |
Precipitation | Showers | Heavy rain or snow, hail sometimes | Showers then clearing |
Clouds | Cirrus and cirrostratus changing later to cumulus and cumulonimbus | Cumulus and cumulonimbus | Cumulus |
Weather conditions associated with a warm front.
Weather Phenomenon | Prior to the Passing of the Front | Contact with the Front | After the Passing of the Front |
Temperature | Cool | Warming suddenly | Warmer then leveling off |
Atmospheric Pressure | Decreasing steadily | Leveling off | Slight rise followed by a decrease |
Winds | South to southeast | Variable | South to southwest |
Precipitation | Showers, snow, sleet or drizzle | Light drizzle | None |
Clouds | Cirrus, cirrostratus, altostratus, nimbostratus, and then stratus | Stratus, sometimes cumulonimbus | Clearing with scattered stratus, sometimes scattered cumulonimbus |
Hey Quynh, one very important note. Take note of your font colour!!! Can't See some parts :)
ReplyDeleteI like how you summarise the parts and the table you did at the back, its very clear.
According to the table, there are some clouds mentioned:
Cumulus clouds are puffy clouds that sometimes look like pieces of floating cotton. The base of each cloud is often flat and may be only 1000 m (330 ft) above the ground. These clouds grow upward, and they can develop into a giant cumulonimbus, which is a thunderstorm cloud.
Cirrus clouds are thin, wispy clouds blown by high winds into long streamers. They are considered "high clouds" forming above 6000 m (20,000 ft). Cirrus clouds usually move across the sky from west to east. They generally mean fair to pleasant weather.
Stratus clouds are uniform grayish clouds that often cover the entire sky. Usually no precipitation falls from stratus clouds, but sometimes they may drizzle.
Luo Yang (22)