Climatology , oceanography Flashcards
What is role of atmosphere
Oxygen CO2 and Nitrogen
Regulate solar heat
No harmful UV rays
Control temperature
What are aerosols
Solid and liquid particles
What is the order of gases present in the atmosphere
Nitrogen > oxygen > argon >co2 > neon> helium> hydrogen
Explain the greenhouse effect
Uneven distribution of the ozone block UV rays
Co2 absorbs radiation and gives heat back
Water vapour absorbs infrared and night heat, gives out latent heat which is the force for storm
Explain the structure of the atmosphere
EXOSPHERE 500 km = helium and hydrogen temperature is very high
THERMOSPHERE 400-500 km = High-temperature
IONOSPHERE 85-400km = Radio transmission as it is electrically charged
MESOSPHERE 60-85 km = temperature reduces to -100 degrees at 80 km, meteorites
Ozone 30-60km = temperature increases by 5° per kilometre
STRATOSPHERE 10-30km = temperature at 50 km is 0°, no clouds … aeroplanes
TROPOSPHERE 8 to 18 km at equator, tropopause causes temperature inversion, temperature falls at 6.5° per kilometre
What is absolute Humidity
Actual amount of water vapour present at the atmosphere
What is relative humidity
Absolute humidity compared to humidity at a particular temperature
What is dew point
The temperature at which air cannot carry any more moisture
What is specific humidity
Weight of water vapour divided by weight of air
What is the insolation
Percentage of heat received by the earth
How does earth absorb heat during the day and during the night
During the day in short we visible light
During the night in long wave infrared
Discuss the ways of heat transfer on the earth
Radiation no contact
Conduction molecular action conductor required
Convection actual transfer of matter
What are the factors that affect the transfer of heat
- Angle of rays
- Duration of sunshine
- Transparency of atmosphere
- If the radius of particle is greater than wavelength then the light is reflected if it is less then the wavelength then scattering takes place
- Land sea differential- Albedo of land is greater than sea Prevailing winds
- Prevailing winds
- Slope
- Or is the distance from sun
What is the meaning of albedo
The percentage of light reflected by a surface
When is the earth closest to the sun
Fourth of July apehelion
When is the earth farthest from the sun
3 jan perihelion
What is latitudinal heat balance
The planetary winds and ocean currents cause transfer of excess energy from the tropics to the poles
The energy is transferred at 50° and 30° latitude therefore these are known as storm zones
What is heat budget how is it maintained
global heat budget is the balance between incoming and outgoing solar radiation.
Short wave is absorbed and long wave is reflected hence the heat budget is maintained
What are isotherms
Isoterms are imaginary lines joining places with same temperature
What are the characteristics of isotherms
are parallel latitude since they have similar sunlight
bend at Ocean and continent boundaries since
different heating of land and sea
Narrow space have a rapid changes
Discuss the behaviour of isotherms on the surface of the earth
Daily and annual temperature ranges are high at interiors
Lowest temperature radiant is at the tropics since the sun is overhead almost all year
Temperature gradient is low at the eastern margins since warm currents
While passing through warm ocean currents they drift phone words
What is lapse rate
Rate of change of temperature moving upwards in the atmosphere
Why does temperature reduce with altitude
Greenhouse gases reduce hence heat absorption reduces
Discuss the adiabatic lapse rate
When there is no loss of heat and no heat exchange between the parcel and the environment
When the parcel of air receives more heat from surrounding the volume increases and density reduces and it rises this is not an adiabatic process
When the air parcel rises , ambient pressure which is pressure of the surrounding reduces with height hence pressure and temperature reduced and volume increases this is an adiabatic process
What is the significance of the adiabatic lapse rate
It defines the stability of the atmosphere
What is latent heat
Heat released and observe during the change of phase slg
What is temperature anomaly
Mean temperature of a place-mean temperature of parallel latitude Largest at north hemisphere
What is temperature inversion
Cooler temperature at lower levels and higher temperature at higher layers
What are the ideal conditions for temperature inversion
Long night therefore outgoing heat is greater than incoming heat
Clear skies therefore with radiation heat can escape
Calm and stable air therefore there is no mixing of air
Discuss the various types of temperature inversion
Air drainage = in valleys the temperature of lower areas increases with altitude at the slopes hence surface heats and rapidly cools then upper layers … inverted
Ground inversion
Air comes in contact with cooler surface and cools , slowly become cooler than upper areas
Subsidence inversion
Air layer descends , the pressure increases… compressed and heated moved down and heat lower layers hence upper layer is more hotter than the lower layer
Frontal inversion
Cold air mass goes under warm air mass
What are the effects of temperature inversion
- Determines cloud types
- Limits convection
- Stop smoke at lower layers
- Daily temperature range is small
- 0°C and valleys but above air is warm
- If the temperature at the surface is less then dew point then there is fog
- Stable condition hence less rain
Draw a diagram of the pressure zones of the earth
Polar high -60 - converge Sup polar low ——Ferrell cell ——Hadley cell Subtropical high =horse 30-5 Equatorial low
Discuss the formation of equatorial low , subtropical high , polar high and subpolar low
Direct heat from the sun at equator hence temperature increases and pressure reduces =equatorial low
Air rises due to temperature increases has become light , rises till tropopause , sinks at 30° north and 30° south and hence form subtropical high
@polar sun rays slant hence cold air moves s@n , n@s ….polar high
Air converges and rises up hence low pressure hence subpolar low
What is the ITCZ
Low-pressure zone where north east and south west winds converge at the equator
What are the forces of the ITCZ
Easterly trade winds Circle at the equator
Air mass
What is the Coriolis force
It is the force due to the rotation of the earth which causes the wind to get deflected If object goes from south and west here to the north and west where it is deflected to the eastIt is zero at the equator and it is maximum at the polls
Draw the position of wind on the earth
Easterly westerly , north-east trade and South East trade
Which ones are known as the roaring 40s and shreaking 60s why
The westerlies are knownThere is ocean in the southern hemisphere hence there is no obstruction in the 45° to 60° south
Discuss the effects of the seasonal winds
In the summer the sun moves north word hence low-pressure zone is created
Therefore the south hemisphere winds go to the north hem - tradeCrossing the equator they deflect to the right due to Coriolis force
Have travelled a long way on the ocean hence have collected moisture which is released at the western edge of the Asian landmass
In winter high-pressure zone is created in the northern hemisphere hence north trade winds go to the south from the Tibetan plateau and hence Northeast monsoon is at the east coast of India
Name some local winds and their regions
Chinook at North America Pampers @ s am Foehn @alps Karaburan @ Russia Loo Sirocco @n af Berg @ s af
Discuss the significance of the foehn wind
Benefits the Alps
15 to 20°C
Helps in animal grazing
Discuss the significance of loo
45 to 50°C
Cause dust storms
During may and June
What is the meaning of geostrophi wind
Wind if pressure gradient and Coriolis force are equally balanced
What is jet stream
Fast flowing narrow meandering air currents in the atmosphere
Circumpolar narrow concentrated bands of air streams
meandering at high velocity
in the upper troposphere
bounded by the low speed wind
and are a part of the upper level westerlies
What causes jet streams
Temperature difference between polar and tropical air masses
Between which cells is the polar jetstream , subtropical jet stream located
Polar jet stream @ polar and Ferrell cellSubtropical jet stream add Ferrell and Hadley cell
Discuss the behaviour of jet streams according to the temperature
Straight line if there is maximum temperature contrastIf difference is less then the meandering starts
What are Rosby waves
Meandering jet streams
Why are the polar jet streams slower than the subtropical jet streams
Polar jet streams move at 6-9 km/h and
subtropical jet streams move at 10 to 16 km/h
Difference is because of the troposphere thickening at the equator
Discuss the features of polar jet stream
It is a permanent jet stream
At summer it moves towards the pole
in winter it moves to the equator
Influences the climate of 60° north and 60° south
Determine the path and speed of temperate cyclones
Discuss the features and effects of the subtropical jet stream
It is a permanent jet stream
It moves by the earths rotation
The whole year it is in the southern hemisphere in summer it moves to the north hemisphere
It is connected to the Indian monsoons
Discuss the features of the tropical eastern jet stream
Also known as African easterly jet stream
It is between the 5° to 20° north
It is a temporary jet stream
in the summer monsoon it increases convection in India
it is caused by the heating of the Tibetan Plateau
Discuss the features of the Somali jet stream
It is also known as the south westerly jet stream
In summer it is at North Madagascar and moves towards the south Indian Ocean during winter
it is the most intense in June and August
What are the effects of jet stream
Maintain the latitudinal heat balance by exchange of air
When jet streams interfere with the surface wind they cause storms
Trace the path of temperate cyclones
They influence the air mass therefore there are prolonged drought or flood periods
AT TEMPERATE REGIONS
Separate cold and warm weather Determine the frontal precipitation and frontal cyclones
What is the air mass, where are they located
Air with distinctive characteristics in terms of temperature and humidity is called in air massThe flow between the surface and the lower stratosphere
What is the condition for formation of an air mass
Gentle air
High-pressure
Less fluctuation in pressure
Extensive divergent air
Discuss the characteristics of a cold air mass
Unstable and turbulent
Cold and moist and Arctic Ocean and southern ocean
Cold and dry at Siberia and North Canada
Discuss the characteristics of a warm air mass
Stable
Warm and dry and the Sahara desert
Warm and moist at tropical oceans
Discuss the characteristics of the continental polar air mass
Located at Arctic and northern North America, Eurasia Antarctica
It is cold dry and stable
In the summer it is anti-cyclonic
In the winter it is clear and stable
Discuss the characteristics of the maritime polar air mass
Located between 40° and 60°
Cold moist and unstable
In the summer it is stable and clear
In the winter it causes fog
Discuss the characteristics of continental tropical air mass
It is located at Sahara and western Asia and Australia
It is dry hot and stable
It does not go beyond source area
Discuss the characteristics of the maritime tropical air mass
Located between the Mexican gulf, the Pacific and The Atlantic Ocean
Warm humid and unstable
In summer cause convectional rainfall
In winter cause fog
What are the effects of air mass
Carry moisture from one place to another
Transport latent heat hence remove heat balance
Cyclones originate by the contact zone of two air masses
What is the front
Three-dimensional boundaries zone formed between the two converging here message of different physical properties
What is frontogenesis
War between two air masses the , formation of a front
Discuss the characteristics of a front
Clockwise in the southern hemisphere
anti clockwise in the northern in this year
Mid latitudinal cyclones are cause by frontogenesis
How is a front dissipated
It is known as Frontolysis One year must wins over the other
State the four types of fronts
Stationary front… The surface position does not change hence the height does not changeThe two masses are not able to push each other hence they enter into a draw Wind is parallel to the frontIt causes frontal precipitation and cyclones and floods
Cold front….Cool air mass replaces the warm air massIt causes thunderstorms and tornadoes
Warm front ….Warm air wins over cool airThe warm air mass is too weak to take over hence it was above the cold air massIt causes gradual temperature moderate precipitation
Occluded front ….Cold air mass ad cool air mass catches up to the warm air mass hence pushes the warm air mass between themThe cold air mass was underneath the warm air massExtra tropical cyclones at western Europe
What is London smog
It is sulfurous smog
Caused by fossil fuels and coal
Increases by dampness and increase in particles
What is Los Angeles smog
Also known as photochemical smog
It is found in urban areas due to automobiles
When nitrogen reacts with the sun hence ozone is formed
It is light brown in colour and reduces visibility
What is haze
Dust or other particles that obstruct the clear sky
What are the effects of smog
Pollution trap by inversion
Precipitation reduces
Sickness
Discuss the smog formed by various pollutants their causes and effects
Nitrogen and nitrogen oxides
By combustion of oil gas forest fires and lightning
Lower visibility yellow smog and reduced plant growth
Volatile organic compounds
Evaporation of fuels and incomplete combustion eye irritation respiratory diseases and reduced visibility
Ozone
By photolysis of nitrogen
Reduce crop and plant growth, damage plastic and rubber
Peroxyacetal nitrate
By reaction of nitrogen oxide with voc Eye irritation and damage to proteins
What is the solution to smog
Renewable energy
Manage vehicles Attention to air-quality index
Alkaline scrubber is reduced SO2 and SO3 levels
Green belts in the city to filter air
Reduce coal-fired plants
What are the factors affecting the rate of evaporation
Amount of water
Temperature
Relative humidity
Surface area
Increase in wind therefore blow out saturated air therefore dry air replaces it hence evaporation
Increase in temperature and reduce in relative humidity and strong winds hence evaporation increases
Evaporation is inversely proportionate to pressure
Inversely proportionate to salinity
When does condensation takes place
When the dew point is less or greater than the freezing point
What happens when the dew point is less than the freezing point
Dew = moisture deposit at a cooler surface
Clear sky and calm air and high relative humidity
Temperature is greater than freezing point
Fog= when highly water vapour air mass cools suddenly
Temperature is above freezing point visibility is less than 1 km
Advectional fog - warm air moves over cold air
White frost= condense at cold surface
Temperature is below freezing point and excess moisture is converted into minute ice crystals
Mist = same as fog but greater in moistureVisibility is 1 to 2 km
What happens when the dew point is greater than the freezing point
Four types of clouds are formed
Cirrus = detached , feathery Cumulus = scattered w flat base Stratus = large surface , layers Nimbus = grey with low ground, shape less
What are ocean currents
Regular volumes of water in a definite path and direction
What are the causes of ocean currents
Primary- initiate
Heat by the sun, the water expands and hence it is elevated at the equator which causes a gradient slow from east to west
Winds, the monsoon- for seasonal reversal
Gravity causes gradient variation
Coriolis force the water to the right in northern hemisphere and
to the left in the Southern Hemisphere
secondary - move
Temperature difference cold and dense therefore sinks
Salinity difference higher the salinity dense therefore sinks
Discuss the types of ocean currents
Surface
at 400 m
Deep water after 400 m
Move all around due to change in gravity and density
Cold ocean currents
Move from cold areas to warm areas
In the equatorial zone they hit the western coast
Above the equatorial zone they hit the eastern coast
Clockwise in the northern hemisphere and anticlockwise in the Southern Hemisphere
Warm ocean currents- opposite of cold ocean currents
What are the effects of ocean currents
- Cold ocean currents form deserts and the tropical region
- Cause fog and arid conditions
- Warm currents bring rain to the interiors example summer rain at the british type climate
- Bring warmness to England and the moderating effect
- Mixing of ocean current oxygen therefore fishing ground
- Cold and warm mix therefore fog and drizzle
- Foggy climate at mixing zones
- Warm and moist @ subtropical regions
dry @ western margin. - Piles of warm water at the tropics therefore cyclones
- Ship usually follow the direction of the current
Why are hot deserts located between 20 to 30° latitude
Rain bearing trade winds blow off shore hence take away the moisture from this region
Westerlies blew away from this region
Winds are desert or cold region belonging
Less cloud formation therefore less moisture
What are tides
Periodic rise and fall of Sealevel once or twice a day due to the direction of the sun and the moon
What is a surge
Movement of water by meteorological effects like winds or atmospheric pressure
What is the tidal bulge
Like an eye Left due to centrifugal force right due to gravity
Factors affecting tides
Movement of the moon and movement of the sun with respect to the earth
Uneven distribution of water
What is semi diurnal tide , diurnal, mixed
Semi = 2h+2l per day
12 hours 25 minutes difference between high and low
Diurnal = One high and one low tide per day
Mixed tide @ north am. west coast , variation in height
What is spring and neap tide
Spring tide is when the sun moon and the earth are in a straight line and
it is a high tide
it takes place on full moon and new moon
Neap tide is when the sun and the earth are in straight line and the moon is perpendicular to the earth
it is a low tide
it takes place seven days after the spring tide
What is a perigee and apogee, perihelion , aphelion
what effects do they have on tides
Perihelion - When the sun is closest to the earth high tidal range
Aphelion - when the sun is farthest to the earth the tidal range is low
Perigee - when the moon is closest to the earth the tidal range is high
Apogee - when the moon is farthest from the earth the tidal range is low
What is ebb
Time between high and low tide when the level is low
What is flood
Time between low and high tide when the level is high
What are coral reefs
They are an ecosystem of calcerous organisms which secrete CAC03Hard corals make coral reefs
How are coral reefs formed
They get the carbon from ZOXANTHELAE - Photosynthesis in a protected environment with carbon dioxide from the calcareous organisms
What are the conditions required for coral reefs to form
Warm water 23 to 27°C therefore in tropics and east margins
Water depth up to 180 feet need sunlight
No cold currents
Salted water free from sediments hence not a delta
Where are coral reefs located
Great barrier coral reef at the Australian coast
Goa Kerala and Sri Lanka
Discuss the types of coral reefs
Fringing reefs separates the sea from land forming a border on the land mass
Barrier reef like islands in the sea
Atoll Circular formation where there is no landmass
What Is the significance of coral reefs
Barrier against erosion
CAC03 production
Subsistence for mangroves
Food chains are developed
What are the statistics regarding coral reef bleaching
The United Nations has reported that:
70% of the Earth’s coral reefs are threatened,
20% have been destroyed with no hope for recovery,
24% are under imminent risk of collapse
, and an additional 26% are at risk due to longer-term threats.
What is coral bleaching what are its causes and effects
When corals face stress by changes in conditions such as temperature, light, or nutrients, they expel the symbiotic algae zooxanthellae living in their tissues, causing them to turn completely white.
This phenomenon is called coral bleaching.
The pale white colour is of the translucent tissues of calcium carbonate which are visible due to the loss of pigment producing zooxanthellae.
Corals can recover if the stress-caused bleaching is not severe.
Coral bleaching has occurred in the Caribbean, Indian, and Pacific oceans on a regular basis.
CAUSES
Increase in temperature
Ocean acidification- oceans absorb more carbon dioxide
Solar radiation and ultraviolet radiation - changes weather patterns
Infectious diseases caused by bacteria. Affect the photosynthesis
Increased sedimentation
Overfishing and pollution from agricultural run-off Coral mining
EFFECTS
Fish rely on coral for food and shelter
Decline in genetic species decline in diversity
Healthy corals attract touristsCauses large shift in fish communities
Protect coastlines by absorbing wave energy
What is the way forward to tackle coral bleaching
Halting unplanned coastal development
Sustainable fishing
Minimising chemical enhanced fertilisers and pesticides
Treating harmful industrial waste
Tackling climate change and global warming
What initiatives have been taken to protect the corals
Initiatives to Protect Corals :
A number of global initiatives are being taken to address the issues, like:
- International Coral Reef Initiative
- Global Coral Reef Monitoring Network (GCRMN)
- Global Coral Reef Alliance (GCRA)
- The Global Coral Reef R&D Accelerator PlatformSimilarly, the Ministry of Environment and Forests and Climate Change (MoEF&CC), India has included the studies on coral reefs under the Coastal Zone Studies (CZS).
In India, the Zoological Survey of India (ZSI), with help from Gujarat’s forest department, is attempting a process to restore coral reefs using “biorock” or mineral accretion technology.
National Coastal Mission Programme, to protect and sustain coral reefs in the country.
Why are coral reefs found in clear tropical waters only
Coral reef is independent ecosystem.
Coral reef consists of polyps and algae.
Both unicellular algae and filamentous algae are present in polyps.
In dead skeleton of coral there is filamentous algae.
While unicellular algae is in the body of polyps.
The polyp releases carbon dioxide . The carbon dioxide is used by algae .
The complete recycling of matter takes place in corals.
For photosynthesis of algae it needs light and clear water.
What is a Watermass
body of ocean water with a distinctive narrow range of temperature and salinity and a particular density resulting from these two parameters.
What are dead zones
Also called hypoxic zones
Hypoxic zones are oxygen-starved areas in the ocean or lakes are areas where very few or no organism survive.
The regions facing such a situation essentially become biological desert.
What are the causes of dead zones
Natural Cause:
In the summer, northerly summer winds work together with the Earth’s rotation to push oxygenated surface water offshore and this coastal water is replaced by low-oxygen but nutrient-rich waters from the depths of the continental shelf by a process known as upwelling.
Once this nutrient-rich water reaches the ocean’s sunlit layers, it fertilizes blooms of phytoplankton.
Eutrophication i.e the process by which extra nutrients are added to the water bodies, stimulating an overgrowth of algae, which then sinks and decomposes in the water.
The decomposition process consumes oxygen and depletes the supply available to healthy marine life
Extra nutrients are added due to fertiliser , domestic and sewage , industries and burning of fossil fuels
Global warming increases temperature and affects flowing manner and lowers the solubility of oxygen
What is the effect of dead zones
Nutrient over-enrichment -behavioral and physiological impacts including reduction in fitness or reproductive capacity, increased mortality and migration.
Increases the metabolism of marine animals.Low oxygen level kills coral reefs.
Elevated nutrient levels and algal blooms can also cause problems in drinking water in communities nearby and upstream from dead zones.
Harmful algal blooms release toxins that contaminate drinking water, causing illness in animals and humans.
Threatened global food supply and fisheries.
Economic Loss due to reduction in potential for commercial fishing.
What are the factors responsible for oceanic salinity variation
Evaporation rate:
Oceans between 20 to 30 degree North and south have high salinity because of
(1) high temperature
(2) low humidity .
Temperate oceans have lower salinity due to lower temperature.
Amount of Fresh water added in ocean:
Equatorial waters have lower salinity due to heavy rainfall and high humidity.
Oceans fed by large rivers like Amazon, Congo, Ganges, Mekong etc have lower salinity.
Melting of icebergs and resultant fresh water intake into Baltic, Arctic and Antarctic ocean waters makes them less saline. Thus, global warming and greenhouse gas effect has indirectly affects the salinity levels of the oceans.
Currents Mixing:In open oceans, currents mix and flow freely, hence salinity is average 35ppt or lower.
Whereas in the Caspian sea, Mediterranean sea, Red sea and other wholly / partially enclosed seas – the fresh water doesn’t mix freely with ocean water hence salinity is higher.
Salinity, temperature and density of water are interrelated. Hence, any change in the temperature or density influences the salinity of an area.
What are the effects of salinity variation
cold water at the poles sinks and slowly moves towards the equator and warm-water moves the cold water at the poles sinks and slowly moves towards the equator and warm-water moves from equator to poles to replace the sinking cold water.
Thus salinity has a great role to play in the formation and circulation of oceanic currents via the thermohaline process.
temperature and rainfall is affected by currents, the level of salinity has indirect role in Earth’s overall climate.
without salt more of the oceans would freeze during winter- affecting the movements of both fish-schools and cargo ships.
objects that might sink in freshwater are able to float in seawater. This has a big effect on life in the sea
Despite having no fins, the plankton are kept perpetually afloat due to the density of seawater.
Without plankton, entire marine ecosystem will collapse
What are the uses of lakes
- Transports - Great lake waterways
- Farms + industry
- Storage
- Hydro electric- hirakund lakes
- Agriculture of dams on artificial lakes- Bhakra Nangal @ gobindsagar
- Moderation of climate land and sea breeze
- Minerals rock salts borax
- Tourist attraction
What are the criteria to declare that the onset of monsoon has started
- Rain-bearing westerlies being at a minimum depth and speed.
- At least 60% of the available 14 stations in Kerala and coastal Karnataka reporting rainfall of 2.5 mm or
more for two consecutive days after May 10. - A certain degree of clouding, indicated by a parameter called ‘outgoing longwave radiation’ (OLR),
being below 200 W/square metre.
What is onset of monsoon
The burst of the monsoon is known as the beginning of the onset of the monsoon and is a phenomenon that involves the sudden changes in the weather conditions and is a characterized by the dry an the wet.
