Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
22 Cards in this Set
- Front
- Back
|
What is the difference between weather and climate?
|
Weather is the atmospheric conditions of a specific place over a relatively short period of time.
Climate is the atmospheric conditions of a specific place over a long period of time, usually 30-35 years. |
|
|
The Southeast - Southwest Monsoon
|
From June to September, the countries in the Southern Hemisphere such as Australia experience winter while countries in South Asia e.g. India experience summer. Due to the the cold temperature, air sinks, developing a region of high pressure over the Australian continent.
Due to high temperature in the countries of South Asia, for example India, air above the South Asian continents rise, developing a region of low pressure over the South Asian continent. As winds travel from a region of higher air pressure to a region of lower air pressure, winds blow from Australia to South Asia forming the Southeast Monsoon. However as the winds pass the equator, due to the Coriolis effect, the winds are deflected to the East forming the Southeast monsoon. Winds sweep over oceans, picking up lots of water vapor and bringing heavy rain to southwestern India and Bangladesh. During these months, the Indian sub-continent usually experiences hot and wet weather. |
|
|
The Northwest - Northeast Monsoon
|
From October to January, the Northern Hemisphere experiences winter while the Southern Hemisphere experiences summer. As a result, an area of low air pressure develops over the Australian continent while an area of high air pressure develops over India.
During the Northeast Monsoon, winds blow across the Asian continent. As winds are cold and dry, they bring little rain to countries such as India and Bangladesh. During these months, the Indian-subcontinents experience cold and dry weather. |
|
|
Causes of Climate Change
|
Enhanced greenhouse effect: Greenhouse effect is a natural process whereby greenhouse gases absorb heat from the Sun's rays and trap it in the atmosphere. (CO2, H2O, Nitrous oxides) With increase in human activities, more greenhouse gases released and trapped within atmosphere creating an enhanced greenhouse effect called global warming.
Rearing cattle and other livestock release methane as result of animals' digestive processes. Cultivation of rice in padi fields and use of inorganic fertilisers release methane and nitrous oxides into the atmosphere. |
|
|
Effects of climate change
|
Melting ice and rising sea levels - In Arctic region, ice caps cover much of Greenland and large icebergs or ice blocks float in the Arctic ocean. The South Pole, which is covered by Antartica, contains about 70 percent of the Earth's ice. Researchers have warned that as much as 50 percent of the arctic sea ice could disappear by 2050 as a result of global warming.
Severe storms - Regions with wetter climates like China, Southeast Asia and Western United States experience higher relative humidity as higher global temps means increased evaporation rates. Increased rainfall in these places causes floods(sometimes). Heat waves & droughts - Places hot and dry like Sahel region, experiences droughts when temps increase. High temps, increase evaporation rates, lakes and rivers dry up. When water bodies dried, there will be less water vapour in the atmosphere. Prevents clouds from forming and hence little or no rain. |
|
|
Tropical Equatorial Climate
|
-Areas between 10degreeN and S of The Equator
-High and uniform mean annual temperature throughout the year.Average of 27 degrees -Small annual temperature range only about 2 degrees -High annual precipitation and evenly distributed throughout the year. Between 1500 to 3000mm in total. -No distinct wet and dry seasons. |
|
|
Tropical Monsoon Climate
|
Areas between 10 degree and 25degrees N and S of the Equator
-High and uniform mean annual temperature throughout the year. Average about 26. -Small annual temperature range but greater than TEC, 6 degrees. -High annual precipitation, with distinct wet and dry seasons. Between 1500 and 3000mm. |
|
|
Cool Temperate Climate
|
-Areas between latitudes 35 degrees and 70 degrees N and S of the Equator.
-High temperature in summer, low in winter. Montreal -10 winter 21 summer. -Large annual temp range 15 to more than 30degrees -Annual precipitation may be low or moderate ranging from 300mm to 2000mm. Snow in winter, rain in summer. |
|
|
Causes of floods
|
Natural:
Excessive Rainfall Storm surges Melting Snow Global atmospheric processes Movement of Earth's surface Human: Urban development Clearing of forests Impact of enhanced greenhouse effect |
|
|
Excessive rainfall
|
Places which experience tropical monsoon climate have seasons of heavy rain. Moist monsoon blows, bring heavy and prolonged rains. Floods occur when excess rainwater is unable to seep into ground or when rivers overflow their banks because channels can no longer contain water.
E.g. Yellow River and Yangtze River in China often overflow their banks after heavy rain, as rain washes large amounts of sediments into river, which are deposited on river bed causing river to be shallower. With time flooding occurs. |
|
|
Storm surges
|
Causes floods in coastal areas. Occurs when strong winds raise waves in ocean to exceptionally high levels. Tropical storms, for eg cause strong winds to blow over ocean, creating gigantic waves which crash onto the coast and flood the land.
E.g. Bangladesh is a country with low lying relief, 35% of country is less than 6m above sea level. As such it is frequently subjected to regular flooding caused by storm surges. When strong winds blow towards Bangladesh from Bay of Bengal, flooding occurs. |
|
|
Melting snow
|
In places with cool temperate climate, melting of snow in spring release large amounts of water into rive and sometimes cause them to overflow.
E.g. In 1986, St John River in Canada overflowed as it could not hold the excess water from melting snow in its channel. Several homes submerged in floodwaters and families had to be evacuated. |
|
|
El Nino & La Nina
|
El Nino - About once every 7 years. Peru heats up, blah blah blah, eastern Pacific increased likelihood of flooding and western Pacific experience droughts.
La Nina- About once every five years, following after El Nino. Western Pacific heats up, increase likelihood of flooding in western Pacific (Australia, Indonesia), and droughts in eastern Pacific. |
|
|
Movements of the Earth's surface
|
2004 Indian Ocean Tsunami, triggered by strong undersea earthquake in the Indian Ocean near Sumatra. Displaces large amounts of water, creating large waves which ripple outwards.
Earthquake also sometimes loosen soil along hills or mountain slopes causing landslide. If loosened soil deposited into river, it might cause water in river to overflow, flooding surrounding areas. |
|
|
Clearing Forests
|
China and Bangladesh cut lots of wood.
Bangladesh - Increased amount of sand and mud washed into Ganges and Brahmaputra Rivers causing floods to occur |
|
|
Urban Development
|
London, areas around the River Thames experience regular flooding as the natural vegetation around the river is replaced with concrete pathways and buildings. Increase surface runoff flowing into River Thames, causing it to overflow its banks.
|
|
|
Natural Causes of droughts
|
Delayed rain, insufficient rain - Tropical monsoon regions, such as Bangladesh and India may suffer from droughts when monsoon winds which bring rain are delayed. This prolongs dry season and droughts occur.
Global atmospheric Processes - El Nino (Indonesia and Australia) and La Nina (Peru) |
|
|
Human Causes of Floods
|
Human
Reduced forest cover - Deforestation in Amazon rainforest has led to worst droughts the Amazon Basin has experienced in the last 40 years. Water levels in Amazon River are so low that miles of exposed river banks have dried up and are eroded by wind. Forests cleared > Reduced vegetation cover > lower rates of transpiration > less WaV > Less clouds less rain. Less trees > ground exposed to direct heating by Sun > dries up quickly Impact of EGE > Global warming causes droughts in drier climates > Sahel in Africa, high temps cause rapid evaporation, dries up land river and lakes. > As water is already very scarce, if no rain to fill WaB droughts occur. More droughts are imminent as global temps are projected to rise as... Overuse of water - Since 2001, people living in village of Kothariya, India, experience drought due to overuse of water. Pop. of 4000 gets water from five water holes that dug deep into the floors of ponds. Dug deep as rivers and wells have dried up. When Pop. grows quickly, more water needed for homes needed for homes, industries and agriculture. Some places depend on rivers and groundwater to meet water needs. |
|
|
Impacts of droughts - Loss of Lives
|
Loss of lives - In 2003 weeks of heavy downpour led to rising floodwaters in the north-central Huai River Basin, located in the provinces of Anhui, Jiangsu and Henan in China. Flood claimed 298 lives and forced people to evacuate from affected areas. Floodplains around Coastal areas and rives provide fertile alluvium attractive for cultivation of crops, densely populated. Thus when flooding occurs, impact is usually high
|
|
|
Damage to property and infrastructure
|
Floodwaters submerge villages and towns > property & infrastructure damaged. Homes ruined roads inaccessible. Disrupts power supply and phone lines, cutting off comm. Costly and takes long time to repair.
In 2005, Hurricane Katrina hit Gulf Coast of USE, leading to massive flooding of several states inc. New Orleans which was worst hit. Flood damage in New Orleans, in terms of property and infrastructure, cost around US$44 billion in total. |
|
|
Spread of diseases
|
Large numbers of homeless flood victims often housed in overcrowded makeshift shelters which lack sanitation and clean drinking water. Such conditions can cause the outbreak of diseases such as malaria and cholera which can spread easily.
E.g. Heavy rains led to extensive flooding in Dhaka, Bangladesh in July 2004. After flood people took cover in makeshift tents where conditions were unsanitary and crowded. |
|
|
Damage to environment
|
Tsunami struck Java 17 July 2006, flooded coastal regions along southern parts
|
