ESYS10 Mid-term examination

Tuesday, February 14, 2006

12:30 PM – 1:50 PM

Answers to review questions and problem sets, case studies allowed. Please pass in your review question answers with your exam paper. No books, no other notes.

I. Fill in the blank or circle correct choice (5 points each)

1. If photosynthesis increases, carbon dioxide in the atmosphere __decreases________.

2. The symbol -----------O indicates ___negative coupling______.

3. The chemical process by which chlorine destroys ozone is called a __catalytic cycle or reaction_.

4. In the troposphere, temperature decreases OR increases with height above the ground.

5. The first international agreement for regulating ozone-destroying compounds was called the ___Montreal protocol_____.

6. In Wien's Law, _wavelength of maximum energy__ depends on the inverse of temperature (times a constant).

7. The monsoon that blows from the land towards the sea occurs in which season? __winter___

8. Visible light has longer OR shorter wavelengths than ultraviolet light. (circle one)

9. A special unit that is used to measure the ozone content of the atmosphere is the _Dobson unit or atmosphere-centimeter___. (two possible answers)

10. Which global water reservoir contains the least amount of water? (atmosphere, ocean, land) ___atmosphere____

II. Short answer (20 points each)

1. The reaction

O + O₂ + M ---> O₃ + M

is part of a mechanism that we studied.

(a) What is the mechanism called? ___Chapman mechanism____

(b) What does this reaction create? ___ozone____

(d) Where does the O come from on the left side of the reaction?

photolysis of O2 in the atmosphere

(e) Consider the feedback between O₃ and photons.

How does O₃ affect photons? absorbs them

How do photons affect O₃? breaks it up

Draw a feedback diagram between O₃ and photons.

O₃ photons

Is the feedback positive or negative?

Negative

2. Consider the greenhouse effect.

(a) Solar radiation enters the atmosphere. What type of radiation is given off by the earth back to space? ___infrared_______

(b) What is the relative size of the wavelength of solar radiation compared with the emitted radation? (You might illustrate this with a sketch of an electromagnetic spectrum) solar radiation wavelengths are shorter

Wien's Law (l_max = 2898/T) indicates that hotter bodies (large T) emit radiation with a shorter wavelength ((l_max)

(d) Greenhouse gases intercept the radiation. Explain how this raises the temperature of the earth's surface. Make sure to explain this in terms of absorbed and emitted radiation.

Incoming shortwave solar radiation is partially absorbed by GHGs.

The remaining solar radiation reaches the ground and heats it.

Meanwhile, GHGs emit radiation in the infrared, both upward and downward.

The downward GHG infrared radiation reaches the ground and heats it.

The ground emits infrared radiation upward.

Part of the ground's radiation passes through the atmosphere and goes to outer space.

The remaining ground's infrared radiation is absorbed by the GHGs.

The GHG emit infrared radiation in response both upward and downward.

The downward infrared radiation further heats the ground.

etc. etc.

(e) Why aren't O₂ and N₂ greenhouse gases?

They are symmetric molecules and not easily excited into a different energy state by photons.

3. A hypothetical planet, called Alpha, is located at a distance r_A from its sun.

Its diameter is D = 2000 km.

Assume that Alpha has no greenhouse gases.

Assume that the albedo of Alpha is 0.

(a) What is albedo? Albedo is the fraction of incoming radiation that is reflected.

(b) What color is planet Alpha? black

(c) If the solar flux reaching planet Alpha is F_A = 1000 Watts/m², what is the total amount of solar radiation in Watts that reaches planet Alpha? Express in terms of D.

Use the area of the cross-sectional circle of the planet:

A = p(D/2)² = 3.14 (2000 km/2)² = 3.14 (1000 x 1000 m)² = 3.14 x 10¹² m²

Solar radiation R_solar = A x F_A = p(D/2)² x F_A = 3.14 x 10¹² m² ( 1000 Watts/m² )

= 3.14 x 10¹⁵ Watts

(d) What is the total radiation (in Watts) leaving planet Alpha in terms of the total solar radiation that reaches it? (Write down an expression.)

Outgoing radiation R_planet = incoming radiation R_solar

(e) What is the flux of radiation leaving planet Alpha in Watts/m²? (Use your answer to (d) and the planet's diameter D.)

Outgoing radiation is emitted from the surface area of the WHOLE planet, not just the plane projection.

So F_planet = R_planet / A_planet= R_solar / A_planet=p(D/2)² x F_A /(4p(D/2)²) = F_A /4

= 250 Watts/m²

(f) What is the temperature of planet Alpha? (Use your answer to (e).)

F_planet = s T⁴ ; s = 5.67x10^-8 W/m²/K⁴

T⁴ = F_planet / s = (250 W/m²) / (5.67x10^-8 W/m²/K⁴)

T = 257.68 K

Some random and possibly useful (and possibly not useful) expressions. (All expressions are correct however.)

III. Essay (30 points). The California Air Resources Board has recently ruled on air pollution from cruise ships. A recent article in the San Diego Union Tribune (2005) describes the ruling; the news release from the ARB gives some background. Questions for the essay follow at the end.

Cruise ship trash-burning curbed | Regulators adopt 3-mile coastal ban

The San Diego Union - Tribune - San Diego, Calif.

Author: Michael Gardner

Date: Nov 21, 2005

SACRAMENTO -- Air quality regulators have doused trash fires on cruise ships traversing the coast.

By unanimous vote last week, the California Air Resources Board adopted rules to implement legislation that bars cruise ships from burning refuse within three miles of shore.

In doing so, smog fighters also signaled their intention to take up similar regulations for many other vessels, including mammoth cargo ships, tankers and military carriers based in San Diego.

"The studies are showing us that incineration by these ships results directly in lots of deaths each year because of the increased health risks," said board member and San Diego County Supervisor Ron Roberts.

Cruise ships are a big part of the California waterfront economy, making 652 stops, including 361 at the ports of Los Angeles and Long Beach. Port calls could increase 25 percent over the next decade, state officials estimate.

Cruise line representatives did not appear at the board meeting Thursday, but embraced the new rules in a letter.

Teri Shore, who monitors cruise ship pollution for Bluewater Network, an environmental group, said she hopes other coastal states will follow California's lead.

Reducing pollution caused by burning trash, ranging from food to rags, will significantly reduce cancer risks and could save as many as 900 lives a year, according to an air board estimate.

The smoke contains arsenic, lead, mercury and nickel, the air board said.

The rules had to be adopted to give inspectors the ability to check compliance and cite violators. The board's order requires vessel operators to maintain records that must be available during onboard inspections.

The legislation imposes a fine of up to $25,000 per violation. Since going into effect Jan. 1, the law has had a noticeable effect. Only two of 26 ships surveyed reported burning waste within three miles of the coast since the beginning of the year, according to the air board.

Cruise ships were singled out by the initial measure, Assembly Bill 471, because of the huge amounts of waste generated by as many as 5,000 passengers per vessel. Incinerators can operate 12 hours a day for as many as six days a week, according to a state study. One limited state survey found ships burn an average of 1,736 tons of trash a year.

Subsequent legislation, AB 771, will broaden the reach of the law when it goes into effect Jan. 1. Most military vessels, state-owned ships and tankers -- even those with minimal crews -- will have to comply with the ban.

The air board is expected to consider similar regulations for those ships next year.

Jerry Martin, a board spokesman, said lawyers still are exploring whether the state can impose restrictions on federal vessels within California's waters.

Credit: COPLEY NEWS SERVICE

------- News Release from the California Air Resources Board-----

November 17, 2005

ARB Adopts Airborne Toxic Control Measure for  Onboard Cruise Ship Incineration

SACRAMENTO - The California Air Resources Board today adopted an airborne toxic control measure (ATCM) for onboard cruise ship incinerators. This action implements and supports state legislation (Assembly Bill 471, Simitian) passed in 2004 that prohibits cruise ships from incinerating waste while operating within three miles of the California coast.

(...text deleted by LDT...)

The ATCM is expected to reduce exposure to emissions from toxic airborne contaminants such as metals, as well as dioxins and furans. The ARB’s action today is expected to reduce the cancer risk from cruise ship incineration to less than two cancer cases per one million people in California. In 1990, the ARB adopted an ATCM for medical waste incinerators to cut emissions of these same toxic compounds.

(....text deleted by LDT...)

In other business, Board members voted to allow manufacturers of inboard and sterndrive boats, typically used for recreation, more flexibility in complying with emissions standards. The Board also approved revisions to the emissions warranty for high performance boat engines due to the shorter lifespan of these engines.

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Write an essay commenting on this article. Consider the following issues: Why are Californians concerned about emissions? Who are some of the stakeholders in this discussion and what are the issues that concern them? What are some consequences (positive or negative) of the new regulation? What are some of the scientific or technical questions that would have gone into this regulation?