Climate Lecture 5- Oceans and Climate Flashcards
What can the ocean store?
Heat, water and carbon dioxide and this storage is greater than the atmosphere
How does global scale oceanic circulation transport water, heat and co2?
Horizontally over large distances at rates comparable to atmospheric rates.
Discuss the relation between oceanic and atmospheric exchange.
They exchange as much heat, water and carbon dioxide between them as each transports horizontally.
What is specific heat?
The amount of heat it takes to raise or lower the temperature of a kilogram of a substance by 1 degree.
Are oceans thermally conservative compared to land?
Yes, there are no large variations in temperature.
How much more heat is required to raise the temperature of water compared to air?
4x
What is specific heat capacity of water?
4180 J/Kg
What is specific heat capacity of air?
1005 J/Kg
What is specific heat capacity of dry soil?
800 J/Kg
What is specific heat capacity of wet soil?
1480 J/Kg
Discuss oceanic-atmospheric exchange in terms of mass.
Precipitation, evaporation and gases.
Salinity, cloud cover and ocean productivity
Discuss oceanic-atmospheric exchange in terms of heat.
Temperature and evaporation
Discuss oceanic-atmospheric exchange in terms of momentum (wind).
Currents
Does latent heat vary seasonally?
Yes, higher in NH in January and higher in SH in July
Discuss oceanic CO2 uptake (biological pump).
Biologically driven sequestration of carbon from the atmosphere to the ocean interior and seafloor sediments.
It is responsible for transforming dissolved inorganic carbon (DIC) into organic biomass and pumping it in particulate or dissolved form into the deep ocean.
There, carbon is stored for millions of years.
It is the part of the oceanic carbon cycle responsible for the cycling of organic matter formed mainly by phytoplankton during photosynthesis, as well as the cycling of calcium carbonate (CaCO3) formed into shells
by certain organisms such as plankton and molluscs.
Discuss ocean acidification.
Oceans currently absorb approximately half of the CO2 produced by burning fossil fuel; put simply, climate change would be far worse if it were not for the oceans.
However, there is a cost; when CO2 dissolves in seawater it forms carbonic acid and as more CO2 is taken up by the oceans surface, the pH decreases, moving towards a less alkaline and therefore more acidic state.
Discuss the role of phytoplankton, DMS and CCN.
DMS= dimethyl sulphide
CCN= cloud condensation nuclei
Phytoplankton in the ocean produce DMS which rises into the atmosphere and can lead to the production of CCN which cause cooling (indirect light scattering by clouds)
Is the CLAWS hypothesis negative or positive feedback?
Negative
What is the CLAWS hypothesis?
- Warmer temperatures mean higher phytoplankton growth and more DMS
- More DMS means more CCN
- Lots of cloud means that sunlight is reflected back into space, leading to cooling
- Cooler temperatures mean lower phytoplankton growth and less DMS
- Less DMS means less CCN
- Fewer clouds means more sunlight reaches the earth which causes warming
- Warmer temperatures mean higher phytoplankton growth and more DMS, etc.
What does CLAWS stand for?
Charlson, Lovelock, Andreae and Warren
Discuss the key components and changes of the ocean.
Key components and changes of the ocean and cryosphere, and their linkages in the Earth system through the global exchange of heat, water, and carbon in the ocean include sea
level rise, increasing ocean heat content and marine heat waves, increasing ocean oxygen loss and ocean acidification.
Climate change-related effects (increase/decrease) indicated by arrows in pictograms. Changes in the cryosphere include
the decline of Arctic sea ice extent, Antarctic and Greenland ice sheet mass loss, glacier mass loss, permafrost thaw, and decreasing
snow cover extent.
How have observations of the ocean been completed over the years?
Historical sampling from buckets - evaporation on the dock could cause bias, only first few metres
Since 20th century more engine room intake temperatures- warming in room can cause bias, deeper sample than buckets
Hull mounted sensors- more accurate than engine room intake, depth of sensor depends on if the ship is light or loaded
Is there a bias in voluntary observing ships collecting sst data?
Yes, NH bias
What are argo floats?
Argo floats measure salinity to monitor the changing hydrological cycle and global volume of ice in our oceans.
Descend to drift depth for up to 3 hours, drift for around 3 days, descend to profile depth for up to 3h then behin profile than begin their ascent and then at surface interval collect GPS data and transmit data. Them repeat until battery death.
