// lecture questions Flashcards
Independent surface (Stevenson screens and ocean
buckets) and upper air observations (balloons and satellite measurements) instrumental records all
show warming. Meanwhile other things that you would expect to change with warming are changing
in the expected sense (e.g. less glacier ice, more water vapor in atmosphere, less Arctic sea ice, less snowcover, . . . )
T R U E
Forcing from greenhouse gases produced by humans
is positive and very well known, forcing from aerosols produced by humans is negative and poorly
known.
true (not as emphasized as first T R U E)
We know that Human Forcing is causing a global
warming of the earth because.
- we know the Co2 is coming from humans
- we know it is warming
- our best models cannot produce the warming observed in the 20th century without inducing the human forcing from GHGs
How do we know for certain that the rising CO2 in
the atmosphere is coming from Fossil fuel combustion?
- CO2 rises at the same time as fossil fuel combustion
- the carbon 13/12 ratio is declining: the new CO2 has the ratio you see in plants, so it must have come from fossil fuel, rather than release of CO2 from ocean water of volcanoes
- there is very little carbon-14 in the new carbon, so it has to have been buried a long time ago - fossil
- the oxygen ratio in the atmosphere is decreasing so CO2 is being added from another reservoir
Sea level can be measured
- with sticks mounted to land by stuck in the ocean
- with satellites using radar altimertry
Currently, the largest sources of sea level rise are:
warming of the ocean and melting of mountain glaciers
Measuring land ice change, like Greenland, can be done with
gravity measurements from orbiting satellites and laser or radar altimetry from satellites or planes
Insolation at the top of the atmosphere is less at high
latitudes that the equator because.
The insolation arrives at a large angle to the surface area in high latitudes and gets spread out more
Which of the following statements is False?
The sky is blue because the atmosphere is cold at high altitudes. the rest are true…
- hotter objects emit more radiant energy per unit of emission area
- hotter objects emit shorter wavelength radiation
- albedo is the fraction of incident solar radiation that is reflected back
The sun emits shorter wavelength
radiation, with more energetic photons than the Earth because
the sun is much hotter than earth
The downward longwave radiation from the
atmosphere provides more Watts per square meter to the surface than the Sun.
true
Solar radiation heats the surface of earth. The
largest of the three terms balancing this solar heating is.
Evaporation – upward turbulent flux of
wet air
The Atmosphere warms the surface via the
greenhouse effect because:
The atmosphere absorbs and emits infrared radiation.
The most important greenhouse gas is:
water vapor (H2O)
The most important greenhouse gas for human-
induced climate forcing is
CO2
Methane is increasing because of
natural gas extraction leakage and rice paddies and cow burps
Global warming potential estimates the impact on
warming of releasing a kilogram of a greenhouse gas into the atmosphere by considering
- the efficiency of the molecule in absorbing IR radiation and warming the surface
- and the time that the released gas will remain in the atmosphere
Although there are many greenhouse gases that
humans are affecting, the primary concern is with carbon dioxide (CO2) because
humans are likely to produce so much of it by burning fossil carbon fuels
Doubling CO2 would produce a climate forcing of
around X Wm-2, while the solar cycle produces a climate forcing of about Y Wm-2
CO2 = 4Wm-2 and Solar cycle = 0.2 Wm-2
How do Volcanic eruptions cool the climate?
Volcanoes injects large amounts of sulfur dioxide into the stratosphere, where it forms small sulfuric acid droplets that stay around a long time and reflect solar radiation, cooling the surface
What are some Differences between Volcanic Eruptions and Human Volcano?
- volcanic eruptions are random and episodic, while the human volcano is more continuous
- volcanic eruptions are most important for climate when they spew SO2 into the stratosphere (more than 10 mi up) while the human volcano mostly only puts aerosols in the troposphere
- the most important volcanic eruptions have been tropical, whereas the human volcano is mostly northern Hem. midlatitudes
- if the human volcano stopped, its aerosol effects would be mostly gone in a couple weeks, while an explosive volcano’s emission effects climate for a couple years
The term Global Dimming refers to:
The decline in observed downward solar radiation
at the ground in all the areas where it was measured during the period from the 1950’s to the 1980’s
** water vapor feedback:
occurs because the lapse rate is positive and because the saturation vapor pressure increases rapidly with temp.
Ice Albedo Feeback is greater in the Northern
Hemisphere (NH) than Southern Hemisphere (SH) because,
- NH has more land, more snow, and has polar ocean.
The biggest positive climate feedback is water vapor
feedback, and the most uncertain climate feedback is cloud feedback.
both are true
The great sand deserts of the Sahara and Arabia can
have annual-mean net negative radiation balance at the Top-of-Atmosphere because
- the surface is very hot and the air is dry
- the surface sand has a high albedo
- the atmosphere supplies the missing heat by the sinking of air
The two largest terms in the global-mean
atmospheric energy balance are,
Latent heating and radiative cooling
when you put ice in a drink it keeps cold because
it takes a lot of energy to melt the ice and all the ice must be melted before the water temp can rise much above 0 C.
The two largest terms in the global-mean SURFACE
energy balance are
Latent cooling and radiative heating
based on the diagram, where do you expect the ocean to be salty (where precipitation is less than evaporation)?
subtropics (around 30 N S)
Potential Evapotranspiration is the amount of
evaporation plus transpiration
That could occur if the surface is wet
The westerly subtropical Jet occurs
30N and 30S at about 12km altitude
The Hadley Cell Transports
Potential energy poleward and Moisture
equatorward
