Global warming test #2 UTA-1330

What is the difference between incoming and outgoing radiation?

Incoming solar radiation is shortwave, ultraviolet, and visible radiation; outgoing terrestrial radiation is long-wave infrared radiation

What is the general idea about earth's energy budget?

Earth's atmosphere does absorb some solar radiation, it does transmit some infrared radiation, and, importantly, it is heated by non-radiative fluxes from the surface

How much incoming solar energy is absorbed at ground level?

Approximately 70%

What happens to the "rest" of incoming solar energy that is not absorbed?

It is absorbed or reflected by clouds, gasses, and dust, or is reflected off of Earth's surface

How much energy is reflected vs emitted as heat energy?

Approximately 30%

What is the "atmospheric window"?

The places with limited or almost no absorption by the atmosphere

What makes greenhouse gasses different from the main constituents of the atmosphere?

- They absorb infrared radiation

- Electric dipole moment is critical for interaction with electromagnetic radiation

- Different absorption spectra for different gasses

What does the observed stratospheric cooling indicate?

Ozone depletion

What is radiative forcing?

The initial response of radiative fluxes at the top of the atmosphere. It can be defined as the change in the radiative balance at the top of the atmosphere (the tropopause) for a given change in one specific process that affects those fluxes with everything else held constant.

What does radiative forcing cause?

It will cause warming if the forcing is positive (more absorbed solar radiation or less emitted terrestrial radiation), and it will cause cooling if the forcing is negative (less absorbed solar or more emitted terrestrial to space).

What is the approximate total anthropogenic forcing?

2.3 (1.1 to. 3.3) W m-2.3

What is global dimming?

The reduction in the amount of global direct irradiance at the Earth's surface that has been observed

What is the difference between climate sensitivity and radiative forcing?

Climate sensitivity is the average change in global mean surface temperature in response to a radiative forcing, which drives a difference between Earth's incoming and outgoing energy.

What are carbon reservoirs in the Earth system?

The ocean, the atmosphere and the land

What are the carbon reservoir's relative sizes?

The ocean is the biggest (40,000 Pg of carbon) , then land (4,000 Pg of carbon), then atmosphere

The atmosphere links all 3 together through rapid exchanges

What are examples of rapid carbon fluxes in the Earth system?

- Gas exchange between atmosphere and ocean

- Photosynthesis and respiration

What are the sources of anthropogenic carbon?

- Humans have had a major impact on the carbon cycle since the industrial revolution

- Deforestation

- Burning of fossil fuels

- Humans emit 10 billion tons of carbon into the atmosphere per year

- 40% of the anthropogenic carbon has been absorbed by the ocean, the other 60% stays in the atmosphere

What is the evidence for anthropogenic activities being the main source of the atmospheric CO2 increase?

CO2 concentration has increased by more than 40%

What can be derived from atmospheric carbon isotope studies in this context?

Fractionation during photosynthesis leads to plants and algae having very depleted δ13C values. Since fossil fuels are derived from ancient plants they are depleted in 13C isotopes as well. Which leads to a decrease in δ13C values of atmospheric CO2

Why is the increase in atmospheric CO2 also causing ocean acidification?

- CO2 dissolves in water and reacts to form carbon acid

- CO2 addition to seawater lowers the pH value

- Adding CO2 to seawater increases its hydrogen ion concentration (decreases its pH) and decreases the carbonate ion concentration

Unequal heating of the Earth's surface, resulting temperature gradient

- Heating is most intense near the equator due to unequal solar irradiance

- Latitude of maximum heat moves north and south of the equator due to seasons

- Energy imbalances establish a temperature gradient between the tropics and the poles

What is the energy imbalance between low and high latitude?

- Net gain in energy at low latitudes

- Net loss of energy at high latitudes

what is meridional heat transport?

Heat transport across latitudes prevent tropics from heating up and poles from cooling down

Where are the atmospheric circulation and surface winds?

Around areas of high and low pressure

Where are the areas of high and low pressure?

- High pressure: Siberia, interior Canada, or the north Atlantic or Pacific,

- Low Pressure: Tibetan Plateau and in the lee of the Rocky mountains.

What is the Coriolis effect?

Earth's rotation causes a deflection of air and water masses towards the right (left) in the northern (southern) hemisphere

What is its impact on flowing air and water?

- Deflection of air or water by earth's rotation

- Deflection of the northern hemisphere to the right

- Deflection of the southern hemisphere to the left

What are jet streams?

- Relatively narrow bands of strong wind in the upper levels of the atmosphere.

- Polar jet stream dominates mid-latitude weather

- Ast upper-level winds form at the boundary between cold dense polar air and warm moist subtropical air

What is the ITCZ?

- The belt of rising air close to the equator

- Major band of thunder storms and squalls (A strong wind characterized by a sudden onset )

What are the latitudes with dry and wet conditions (location of deserts)?

- Regions of large precipitation: Africa, South America, and Asia

- Regions of little precipitation: the Sahara, the Arabian Peninsula, regions in central Asia, southwestern parts of North America, central and western Australia, parts of South America west of the Andes, and southwestern Africa

How do phase transitions of water within the hydrological cycle contribute to energy transfer in the climate system?

- It links physical and biological processes

- A large amount of energy input is required to overcome this force for a transition from the liquid to the vapor phase

What is latent heat?

Energy required for a phase change (liquid to vapor change)

What is "special" about water's specific heat?

Water has high heat capacity because much energy is needed to warm it

What is the resulting heat uptake of ocean vs. atmosphere?

- Ocean has absorbed about 90% of excess energy

- Ocean circulation is global

What are the surface ocean circulations?

Ocean's equivalent of weather systems in the atmosphere

What are gyres?

a large system of rotating ocean currents formed by global wind patterns and the earth's rotational force

What is the difference between warm and cold currents?

- Warm: the poleward flow along the western boundaries of the subtropical gyres ( Gulf Stream, the Kuroshio, and the Brazil Currents)

- Cold: Equatorward currents along the eastern boundaries (California or the Peru (or Humboldt) Current)

What is tropical divergence?

Occurs when a stronger wind moves away from a weaker wind or when air streams move in opposite directions

What are the characteristics of the Gulf Stream?

- Up to 2 miles per hour and can transport up to 100 sverdrups

Begins in the

- Caribbean and ends in the northern North Atlantic.

- Transfers and releases heat energy

What are the characteristics of the Antarctic Circumpolar Current?

- Flows clockwise from west to east around Antarctica. Therefore, it flows eastward.

- Mostly wind driven

- Strongest ocean current on the planet and flows up to more than 100 Sv

- The wind creates divergence at the surface. It extends from the surface of the sea to the deep ocean

- Current is irregular because of land masses in and out of the ocean, as well as prevailing winds

What are the temperatures and salinity distribution in the surface ocean waters (general pattern)?

- The density of sea water is determined by temperature and salinity

- Colder water is located in lower latitudes

- There is a blob of higher salinity in the North Atlantic

Thermohaline circulation is the main driver, what are the NADW and AABW?

- North Atlantic Deep Water (NADW) can be identified as a water mass with relatively high salinity between about 2 - 4 km depth

- Fresher Antarctic Bottom Water (AABW) flows north below NADW. It is colder and therefore denser than NADW

Tropical Cyclones: Formation over warming tropical ocean

A tropical cyclone is a warm-core, low pressure system without any "front" attached, that develops over the tropical or subtropical waters

Tropical Cyclones: Important heat transfer mechanism

The mechanism for the heat transfer is principally by thermohaline circulation rather than by wind-driven circulation.

What causes monsoons?

The sun heating up the land and the Pacific Ocean at different rates, with land surfaces warming more quickly than the ocean

When do monsoons occur?

June-September

What weather do monsoons bring?

Extremely wet or extremely dry weather to an area.

What are the positive characteristics of the NAO (North Atlantic Oscillation)?

The positive NAO phase represents a stronger than usual difference in pressure between the two regions.

What are the negative characteristics of the NAO (North Atlantic Oscillation)?

The reverse with a weaker than usual difference in pressure.

What is El Niño/Southern Oscillation?

A warming of the ocean surface, or above-average sea surface temperatures

El Niño/Southern Oscillation: What happens in the Pacific region?

Sea surface temperatures over the central and eastern Pacific become warmer than normal.

What is the impact of El Niño/La Niña in the US?

- El Niño: Wetter conditions than usual in the Southern U.S. and warmer and drier conditions in the North.

- La Niña: increase Atlantic hurricane season activity.

-- Winters tend to be drier through the southern tier of the US

-- Result in wetter (and snowier) conditions for parts of the northern tier of the US.

What are the definitions and features of the PDO (Pacific Decadal Oscillation)?

- A long-term ocean fluctuation of the Pacific Ocean.

- From ocean surface topography data, together with other ocean and atmospheric data, scientists can determine whether we are in a 'cool' phase or a 'warm' phase.

What are the definitions and features of the AMO (Atlantic Multidecadal Oscillation)?

- An ongoing series of long-duration changes in the sea surface temperature of the North Atlantic Ocean

- These changes are natural and have been occurring for at least the last 1,000 years