L1 - Introduction to the Earth's Climate System Flashcards
What is the difference between Weather and Climate?
Weather is the conditions of the atmosphere at a certain time and place on a daily or weekly basis, whereas, climate is the average weather conditions on a timescale of 30 years (as defined by the WMO)
What is the definition of Climate Change as outlined by the IPCC?
“A change in the state of the climate that can be identified by changes in the mean and/or variability of its properties, and that persists for an extended period, typically decades or longer”
Which 2 layers of the atmosphere are we most interested in for climatic changes and where are most of the atmospheric gases found?
The Stratosphere and Troposphere
80% of gases are found in the Troposphere
What role do clouds play in warming and cooling the Earth’s climate?
They trap outgoing solar radiation, which warms the planet and they reflect incoming solar radiation, which cools the planet
Together Antarctica and Greenland’s Ice Sheets equate to how much sea level change?
70m
What role does Sea Ice play as an insulator?
The ocean is isolated from interacting with the surrounding atmosphere and the albedo effect of the ice reduces the surrounding air temperatures
Why is Carbon monitored in Hawaii?
Because of the clean atmosphere
What are the short-term and long-term variations in CO2 caused by?
Short-Term: The Boreal Forest
Long-Term: Fossil Fuels and Deforestation
What role do algal blooms play in the Biosphere with regards to the Carbon Cycle?
They fix Carbon from the oceans surface
What is the difference between the Organic Carbon Pump and the Carbonate Counter Pump?
The Organic Carbon Pump draws in CO2 to the oceans whilst the Carbonate Counter Pump releases CO2 to the atmosphere
Name a location where cloud nucleating gases are common
The Amazon Rainforest
What is DMS?
Dimethyl sulphide, which is a sulphur compound (a GHG)
How much greater is the oceans heat capacity compared to the land?
60x greater
How much greater is the oceans heat capacity compared to the atmosphere?
1000x greater
Why is the oceans heat capacity so large? (Give the 2 main factors)
- Larger Specific Heat of Water
2. Mixing
How much more Carbon do the oceans contain compared to the atmosphere?
~50-60x more
How much of the Carbon released into the atmosphere since the Industrial Revolution is now in seawater?
30%
Are there long or short residence times in the geosphere?
Long
What impact does uplift have on global temperatures?
It causes increased weathering and CO2 removal, which leads to global cooling
What impact does seafloor spreading have on global temperatures?
It depends on the rate, which will impact the rate of CO2 input and removal - fast seafloor spreading causes a rapid input of CO2 which leads to a warmer climate which leads to increases weathering with causes removal and reduced warming whereas slow CO2 input leads to cooler icehouse conditions, which reduces weathering, CO2 removal and therefore a reduction in cooling
What do ice sheets cause?
Compression
What is the MPT?
Middle Pleistocene Transition
What was said to cause the MPT?
Ice sheet erosion of regolith, meaning it was now stable allowing for ice sheet growth
How much more is insolation energy compared to internal heat sources?
3680x more
Why is the climate viewed as a heat engine?
Because climate uses heat energy from the sun to keep the atmosphere and the ocean moving
Name 5 parts of the Earth’s Heat Engine
- Evaporation
- Convection
- Rainfall
- Winds
- Ocean Currents
What does thermally direct mean? and which cells in the atmosphere are thermally direct?
It means stable
Hadley and Polar Cells
Why are Ferrel Cells unstable?
They are secondary circulation features, which depend on the Hadley and Polar cells for their existence
Why is the ITCZ important?
Its shifting North and South influences the tropical monsoons seasons
How much heat is transported from the tropics to the poles by ocean currents?
30%
What is the primary driver of ocean currents?
Wind
Name 4 drivers of ocean circulation
- Ekman Spiral
- Subtropical Gyres
- THC
- MOC
What is the differences between THC and MOC?
THC is theoretical whereas, MOC is observational
What are the L, N, W and R zones for the MOC?
L: Labrador Sea
N: Nordic Seas
W: Weddel Sea
R: Ross Sea
Why is the AMOC an important consideration for climatic changes?
It slows down when it is colder and Nordic Seas have ice coverage
What is the Radiative Equilibrium?
The flow of incoming and outgoing energy in the Earth’s energy budget must be equal
Where must the energy budget balance?
- The surface
- The top of the atmosphere (TOA)
- The atmosphere in between
What is the TSI? and what is it also called?
Total Solar Irradiance (1360 W/m2)
The Solar Constant
What is the TSI averaged across the entire planet not just for the TOA?
340 W/m2
What is the average albedo on earth?
0.30
How much energy is absorbed at the surface?
48%
How much energy is reflected?
29%
How much energy is absorbed by the atmosphere?
23%
Name 3 ways in which energy leaves the surface
- Evaporation
- Convection
- Thermal Infra-Red Energy
How much energy is transmitted downwards by the atmosphere?
70-75%
How much is back radiation equivalent to? what does it cause? and what is this known as?
Eqv. to 100% insolation => additional surface warming of 30degC => the greenhouse effect
Name 3 climate Forcing’s
- Changes in Earth’s Orbit
- Changes in Solar Output
- Changes in greenhouse gas concentration
What is the primary consideration for interactions?
Feedback Mechanisms
What is Positive Feedback?
When there is a greater response than that produced by the initial forcing
What is Negative Feedback?
When there is a smaller response than that produced by the initial forcing
What must be the same for a large climate response?
If the timescale of the forcing and the system are similar
What is cyclic climatic forcing?
The production of a number of cyclic responses, each of which depends on the response time of the climate component
What does Paleoclimate do?
Reconstructs the response and combines it with the forcings to understand the interactions
What are the 5 components of the Earth’s System?
- Atmosphere
- Cryosphere
- Biosphere
- Hydrosphere
- Geosphere
What are the 3 stages of the Earth’s System?
- Forcings
- Interactions
- Responses