weather

troposphere

troposphere

• decreases of temperature with height

• increase in wind speed with height

• fall in pressure

• unstable layer due to the presence of cloud, pollutions water vapour and dust

• tropopause marks the outer edge of the troposphere and the limit of the earth’s weather and climate

stratosphere

temperature + wind increase with height

• boundary marked by the stratopause

Mesosphere

• With height = fall in temp, high winds, pressure decreases

• Boundary marked by the mesopause

Thermosphere

Outer layer of the atmosphere

• Increase in temperature in height → exceeds 1000°C, due to presence of atomised oxygen (O3)

Weather

The state of the atmosphere at a local level, usually on a short-time scale of minutes to months

Climate

The long-term behaviour of the atmosphere in a specific area (30+ years)

Atmosphere

An envelope of transparent, odourless gases help to the earth by gravitational attraction

Earths atmospheric heat budget

Where heat in the atmosphere comes from and where it goes, the amount of energy received from the sun in a particular location/time of year depends on …

1. Solar constant

2. Distance from the sun

3. Altitude of the sun in the sky

Solar constant

The amount of energy arriving as insolation from the sun - varies according to sunspots

Distance from the sun

Varies due to the earth’s orbit, receive m9roe or less at different times of year

Altitude of the sun in the sky

Equator → lower altitude = higher amounts of insolation

At higher altitude we have oblique rays and therefore less insolation - same amount of energy but it is over a wider distance

Albedo

Reflectivity of a surface

Urban area = 10-25%

Glacier + fresh snow = 95%

Continentiality

Land and sea heat up and cool down at different rates

• the land heats up and cools down quicker than sea due to the specific heat capacity of water being twice that of the land. Coastal regions have a smaller temperature range than inland areas

Ocean currents

• warm = heat away from equator

• Cold = heat returned to the equator

• They turn clockwise in the northern hemisphere and anti=clockwise in the southern hemisphere

Altitude

Insolation turns from light energy, into heat energy, upon impact with a solid of a liquid. It follows that the further one is from this source of heat, the colder it is

Humidity

A measure of the amount of water vapour in the atmosphere. Warm air can hold more water vapour than cold air. In humid weather the amount of water vapour being held is between 80-99% of the maximum

Absolute humidity

The mass of water vapour in a cubic metre of air (g/m3)

Relative humidity

The amount of water in the air at a given temperature

Dew point

The temperature at which unsaturated air becomes saturated and water droplets begin to form

Horizontal heat transfer

80% of heat transferred away from the tropics is carried by winds, the other 20% transferred by the ocean currents

Vertical heat transfer

Transferred vertically by radiation, conduction and convection

Sensible heat transfer

Moves heat from warmer to cooler objects by conduction when they are in direct contact

Convection

When a fluid such as the atmosphere or ocean carries heat energy away from a surface

Latent heat transfer

Latent heat it heat that is taken up and stored as molecular motion when a substance changes state from solid to a liquid, liquid to a gas

Wind

The movement of air form high pressure to low pressure

Isobars

(Unit of pressure) the closer the isobars are - the steeper the pressure gradient and faster the wind

Coriolis effect

Objects moving in a straight line appear to curve due to the rotation for the earth

Northern hemisphere - anti-clockwise

Southern hemisphere - clockwise

Jet streams

A narrow variable band of very strong predominantly westerly air currents encircling the globe several miles above the earth. There are typically two or three jet streams in each of the northern and southern hemisphere

ITCZ

Inter-tropical convergence zone

Tricellular model - influence on climates

Equator - two Hadley cells meet, causing rising air and low pressure - lots of rain, creates rainforests

Sub-tropics - air descends between Ferrel and Hadley cell, high pressure; dry conditions, creates deserts and xerophytes

Mid-latitudes - polar and ferrel cells converge, area of low pressure - ever-green and deciduous forests.

Desert Climate: Al-Kufrah, Libya

Lat: 24°, Long: 23°N

January = 14°C, 0mm rain, 39% humidity

June = 32°, 0mm rain, 16% humidity

Where: Kufra District of Libya - middle of Sahara Desert, 380m above sea level

Climate influenced by: Mediterranean Sea and Sahara desert

Equatorial Climate: Belem, Brazil

Lat: -1.4°N, Long: -48°E

January = 30°C, 155mm precipitation

June = 32°C, 386mm precipitation

Wet season = ITCZ directly overhead and weather is unstable

Dry season: ITCZ moves to opposite hemisphere, high pressure zone brings anticyclones

Mediterranean climate: Rabat, Morocco

Lat: 34°, Long: -6.8°

January = 17°C, 82mm rain

June = 25.4°C, 4mm rain

North Pole climate: Reykjavik, Iceland

Lat: 64°N, long = -6.8°

January = 17°C, 82mm precipitation

June = 12°C, 44mm precipitation

Above equator: Kano, Nigeria

Lat: 12°N, Long: 8.6°E

January = 22°C, 5mm precipitation

June = 28°C, 110mm precipitation

Tricellular model: in summer between southern Hadley cell, location of ITCZ is nearby, causing wetter weather in summer. Winter - Kano is under the northern Hadley cell, further away from the ITCZ, drier Winter season

monsoon

the seasonal reversal of winds given wet an dry seasons

what is monsoon movement controlled by?

1. Movement of the ITCZ and Hadley cells

2. Position next to a warm ocean

3. A relief barrier e.g. Mountain range

Air masses which influence Britain’s climate

Artic Maritime (Am)

Polar Maritime (Pm)

Polar Continental (Pc)

Tropical Maritime (Tm)

Tropical Continental (Tc)

depression

have well defined warm and cold air fronts, and multiple stages within their cycle and bring a series of weather events as they pass over. The positioning of the depression is dependent on the positioning of the air masses present an therefore change throughout the year and cause variation within weather

anti-cyclone

high pressure system - characterized by the rotation of air around a central area of high atmospheric pressure

They are associated with stable and calm weather conditions. They are typically characterized by clear skies, light winds, and little to no precipitation. Due to the sinking air within the anticyclone, it tends to inhibit the formation of clouds and promote atmospheric stability.

adaptation

getteing ready for climate change in order to be more resilient

mitigation

trying to prevent or reduce climate change/extreme weather by reducing GHG’s emissions

urban heat island effect

warm area created by an urban area

• building materials absorb heat during day then release at night

• heat form industry, building, traffic and air pollution

  • effect is greatest at night and in high pressure situations

smog

smoke and sulphur dioxide from burning coal either mix with existing fog or cause it to thicken by additional condensation nuclei into already saturated air

wind in urban areas

1. Surface is uneven - creates frictional drag - leads to turbulence

2. high buildings slow air flow and channel flow into ‘canyons’

3. clear nights there can be surface inflow from cooler areas

reducing air pollution in cities - technological innovations

• catalytic converters reduce emissions from car exhausts

• solar panels + renewable energy

• electrostatic precipitator - uses an electrical charge to remove particles from gas

reducing air pollution in cities - Land-use planning

• Curitiba, Brazil → zoning e.g. heavy industry in one zone, housing in another

• Singapore → alternative building heights to allow greater

reducing air pollution in cities - Vehicle restrictions

• London - road pricing; daily congestion charge

• Singapore - vehicle ownership heavily taxed

• manila - registration plates restrict which days car can drive e.g. Tuesdays and Fridays only

reducing air pollution in cities - legislation

• UK - standards set by DEFRA; monitoring of air quality

• USA - 1960’s - clean air act - 80% decrease in sulphur dioxide emission from 1970 - 2006

reducing air pollution in cities; case studies

Copenhagen

• greenware - helps cyclists pace their journey to avoid red lights

• 9/10 own bicycle, only 4/10 own a car

Madar

• 100% renewable sustainable energy city

• buildings orientated to maximise shade, narrow gaps between them to channel air

• electric pods on rails to replace cars

London ULEZ

• Black cabs exempt for 15 years, reduce pollution by 1/2 in centre London

• 13-year-old petrol cars and 4-year-old diesel have to pay

• Euro6 standards → buses + lorries have to meet

the hockey stick debate graphs

recognises/agrees which change that is happening - anthropogenic climate change

tipping point

a threshold that, when exceeded can lead to a large change in the sate of a system, many potential tipping points have been identified in the physical climate system