Assignment 1 Flashcards
What is ‘climate’?
The average weather
What is the international standard for the averaging period of climate?
30 years
What is the difference between weather and climate?
Weather deals with the state of the atmosphere at a particular time. Climate deals with the average state of the atmosphere over some extended time period. It is a statistical measure and normally does not vary much.
What are the two most common measurements used to describe the climate and its geographic variation?
Temperature and precipitation
What is the Koeppen Climate map?
It depicts regions with similar climates.
What does it take to measure the climate?
Taking hourly or daily weather observations for many decades (at least 3) at many stations evenly distributed around the world.
What is a Stevenson screen?
A weather box that measures temperature, humidity, pressure and wind.
To what height do weather balloons profile?
The lowest 30km of the atmosphere twice a day around the world.
What are four different observations showing that climate change is happening right now?
Global annual mean surface air temperature
Global mean sea level
Arctic summer sea ice extent
Atmospheric carbon dioxide concentration and ocean acidification
2015 was the warmest year ever recorded since what year?
1880
How much has the global average surface air temperature warmed in the last 100 years?
The global average surface air temperature has warmed about 1.0’C in the last 100 years
Effects of warming oceans and melting continental ice and snow lead to what?
Sea level change
Which month has the minimum arctic sea ice extent?
September
The late summer Arctic will be ice free in how many years?
50
as the amount of dissolved CO2 in the ocean increases, the ocean acidity…
increases.
Oceans make up 71% of the earth’s surface and are huge reservoirs of …
heat that impacts climate
Why doesn’t air fall down?
The decreasing air pressure with height creates an upward pressure force that balances the downward force of gravity.
Clouds, precipitation and weather occur in which atmospheric layer?
the troposphere
What are the constant gases in the earth’s atmosphere?
Nitrogen (N2) Oxygen (O2) Argon(ar) Neon Helium Hydrogen
What are the variable gases in the earth’s atmosphere?
Water Vapour Carbon Dioxide Methane Nitrous Oxide (N2O) Carbon Monoxide (Co2) Ozone (o3) Chlorofluorocarbons (CFCs)
What is the composition of dry air?
From greatest to least: Nitrogen Oxygen Argon Carbon Dioxide Neon ...
Why do we determine residence time?
To tell us how long a typical gas molecule resides in the atmosphere, or how long it takes an excess amount of that gas to be removed.
Why is the concept of residence time important?
When estimating future climate change, we need to know how long it will take the extra anthropogenic carbon dioxide to be removed naturally from the atmosphere.
What is the calculation for residence time?
Reservoir size/outflow rate
Which atmospheric gas has the longest residence time?
Nitrogen
Why is actual residence time of Carbon Dioxide different than the expected one?
Rapid photosynthesis
What are the main greenhouse gases?
Water Vapour Carbon Dioxide Methane Nitrous Oxide Ozone Chlorofluorocarbons
Nitrogen sinks?
Nitrogen fixation: converts nitrogen gas into forms that organisms can use. Caused by bacterial action and lightning. Important for fertilizer production, but it creates nitrous oxide which is potent greenhouse as.
Nitrogen sources?
Denitrification: Bacteria converts fixed nitrogen into N2 or Nitrous Oxide. N2O is eventually converted into N2 by photodisassociation but it takes over a hundred years on average.
Oxygen sources?
Photosynthesis (plant growth): Uses sunlight to produce carbohydrates and oxygen
Oxygen sinks?
Respiration (reverses photosynthesis)
carbohydrates and oxygen produce energy, CO2 and H2O. In the absence of oxygen anaerobic decomposition is performed.
Combustion; oxygen reacts with materials that are burning.
Oxidation: Oxygen reacts with certain minerals in the earth’s crust.
Carbon Dioxide sources?
Respiration
Decomposition (of organic material)
Combustion (biomass and fossil fuel burning)
Volcanism (outgassing of Earth’s interior)
Carbon Dioxide Sinks?
Land photosynthesis (Land sink due to plant growth)
Ocean physical and biological transfers (ocean sink)
Burial of organic carbon in the sea floor
Weathering of rocks (geological time scales)
Water Vapour source and sinks?
Source: evaporation from the surface.
Sink: condensation and precipitation back to surface.
Is water vapour a greenhouse gas?
It is a strong greenhouse gas. Enhances warming compared to increasing carbon dioxide along. (positive feedback for global warming)
What is the earth’s ‘albedo’?
The amount of solar energy reflected back to space.
Greenhouse gases are composed of how many atoms?
More than 2
What happens when the vibrational frequency of a molecule matches the infrared radiation wave frequency?
the molecule is able to absorb and emit the infrared radiation. This makes it a greenhouse gas.
The six main greenhouse gases are?
Carbon Dioxide Co2 Methane CH4 Nitrous Oxide n2o Water H2O Ozone O3 Chloroflurocarbons
Does ideal combustion ever happen?
No
Where is most of the earth’s water?
The oceans
What’s the average ocean depth?
3.7km
Why are the oceans key in determining climate and climate change?
Because of their ability to store and transport huge amounts of energy.
What is the thermocline layer of the ocean?
Where the ocean temperature decreases rapidly with depth.
Why is the deep ocean cold?
Because of the source is the polar sea surface.
Where is the salinity in the ocean highest?
Where the evaporation of ocaen water to the atmosphere is the highest.
Where is the salinity lowest in the ocean?
Where the precipitation is greatest (more fresh water being addeD)
How do we determine the sea surface density?
With temperature and salinity
