hw 5 - cc

What does optically thin mean?

transparent

What does optically thick mean?

opaque

What do we call the layer of the Sun that emits light to space?

photosphere

What color are clouds as seen from space?

white b/c water drops and ice scatter all wavelengths

How deep into a gas does the gas emit radiation like a solid surface?

 

τ = 1

The optical depth τ for some path of light through a gas depends on

all of the above

Why is the sky blue?

gas molecules scatter short wavelengths more than long wavelengths

From what optical depth into the Sun does the Sun emit light to space?

τ = 1

Large optical depth τ ≫ 1 corresponds to being

optically thick

Small optical depth τ ≪ 1 corresponds to being

optically thin

On planet Cruftulon, the effective height of longwave emission to space is at 3 km where the temperature is 310 K. If the lapse rate in Kruftulon’s dry atmosphere is 10 K/km, what is the surface temperature?

340 K

Which more strongly absorbs longwave radiation?

water vapor

What best describes the atmospheric greenhouse effect?

the atmosphere lets shortwave pass through but greenhouse gases readily absorb longwave

On planet Zorkon, the effective height of longwave emission to space is at 9 km where the temperature is 210 K. If the lapse rate in Zorkon’s dry atmosphere is 10 K/km, what is the surface temperature?

300 K

Who is credited with identifying the gases responsible for the greenhouse effect?

John Tyndall

Which of the following gases is transparent to longwave radiation?

oxygen

Which of the following is not a greenhouse gas?

nitrogen

Who is credited with postulating the existence of a greenhouse effect and thereby kicking off the field of climate science?

Joseph Fourier

In what year was the greenhouse effect postulated, thereby initiating the field of climate science?

1824

Which of the following gases is relatively opaque to longwave radiation?

carbon dioxide

Why is the amount of oxygen in the atmosphere decreasing?

oxygen is being reacted with carbon to make carbon dioxide

In what year did congressional testimony first raise public awareness about global warming?

1988

In what decade did measurements on Mauna Loa first document rising concentrations of CO₂?

1960s

What is the modern best estimate of Earth’s climate sensitivity?

3 K

Who is credited with alerting the public to global warming with his congressional testimony?

James Hansen

What was the preindustral concentration of carbon dioxide?

280 ppm

What is the mean of 0, 4, and 8?

4

Who first predicted global warming and made a calculation of Earth’s climate sensitivity?

Svante Arrhenius

If Earth’s mean temperature increases from 288 K to 291 K when CO₂ is doubled from its preindustrial concentration, what mean temperature would you expect if CO₂ were quadrupled from its preindustrial concentration?

294 K

Climate sensitivity is the

change in temperature for a doubling of CO₂

Which causes the greater amount of additional warming?

an increase of CO₂ from 300 to 400 ppm

Who is credited with alerting scientists to global warming by documenting the rising concentrations of carbon dioxide in the atmosphere?

Dave Keeling

What is the modern estimate for the likely range of Earth’s climate sensitivity?

1.5 to 4.5 K

The first prediction of global warming was made in what year?

1896