Chlorofluorocarbons in the Chlorofluorocarbons in the OceanOcean

Cesar ColonCesar Colon

August 1, 2005August 1, 2005

Ocean Tracer GroupOcean Tracer Group

Cesar ColonCesar Colon

Dr. Tim HallDr. Tim Hall

Dr. Christian RodehackeDr. Christian Rodehacke

Rayhan AhmedRayhan Ahmed

Scott AlfanoScott Alfano

IntroductionIntroduction

• Chlorofluorocarbons (CFCs) are trace gases Chlorofluorocarbons (CFCs) are trace gases of industrial origin and are infamous for of industrial origin and are infamous for their role in stratospheric ozone depletion. their role in stratospheric ozone depletion. Less well known the fact that a small Less well known the fact that a small fraction of atmospheric CFCs have entered fraction of atmospheric CFCs have entered the ocean via gas exchangethe ocean via gas exchange

• CFCs are chemically inert in seawater, and CFCs are chemically inert in seawater, and are carried by currents and turbulent mixingare carried by currents and turbulent mixing

Introduction (cont.)Introduction (cont.)

• Propagation of CFCs from surface entry Propagation of CFCs from surface entry points to ocean interior provides crucial points to ocean interior provides crucial information on rates of ocean transportinformation on rates of ocean transport

• This information can be applied to This information can be applied to quantities such as COquantities such as CO22 and heat and heat

Project TasksProject Tasks

• Work with ocean CFC data to document Work with ocean CFC data to document the evolution of CFCs in ocean surface the evolution of CFCs in ocean surface waters; Quantifying this evolution is the waters; Quantifying this evolution is the first step in extracting information from first step in extracting information from CFC surface-to-interior transport ratesCFC surface-to-interior transport rates

• Work with measurements taken during Work with measurements taken during several sea-going research routes, coupled several sea-going research routes, coupled with the observed atmospheric CFC historywith the observed atmospheric CFC history

Project Tasks (cont.)Project Tasks (cont.)

• Compare actual surface water CFC Compare actual surface water CFC concentrations to those that would be concentrations to those that would be expected if surface water CFCs were in expected if surface water CFCs were in equilibrium with atmosphere, using well equilibrium with atmosphere, using well known equilibrium relationshipsknown equilibrium relationships

Project GoalsProject Goals

• Quantify the ocean’s role in sequestering Quantify the ocean’s role in sequestering quantities of CFCs and other gases in quantities of CFCs and other gases in order to better understand the Earth’s order to better understand the Earth’s climateclimate

• Learning how the difference from air-sea Learning how the difference from air-sea equilibrium of CFCs has changed over timeequilibrium of CFCs has changed over time

Atmospheric HistoryAtmospheric HistoryXCFC Dry Air Vs. T ime

0

100

200

300

400

500

600

1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

Year

XC

FC

Dry

Air

CFC-11NothernHemisphere

CFC-11SouthernHemisphere

CFC-12NorthernHemisphere

CFC-12SouthernHemisphere

The Indian OceanThe Indian Ocean

• Well represented during WOCE, therefore Well represented during WOCE, therefore plenty of dataplenty of data

• Some data goes back to late 1980s. It is Some data goes back to late 1980s. It is important to have well documented important to have well documented history because it provides more detail for history because it provides more detail for analysisanalysis

Indian Ocean DataIndian Ocean Data

Indian Ocean Data (cont.)Indian Ocean Data (cont.)

Indian Ocean Data (cont.)Indian Ocean Data (cont.)

Region AnalyzedRegion Analyzed

• We looked for a region with large time overlap We looked for a region with large time overlap in terms of data gathered, as well as a small in terms of data gathered, as well as a small enough region so that T and S don’t vary muchenough region so that T and S don’t vary much

Indian Ocean CFC-11Indian Ocean CFC-11CFC-11 Actual & Theoretical Values Vs. Time

Nov-87Dec-87

12/1/1994

Jan-95Jul-95

Apr-95Jun-95

Feb-96

0

0.5

1

1.5

2

2.5

3

Feb-86 Jul-87 Nov-88 Mar-90 Aug-91 Dec-92 May-94 Sep-95 Feb-97

Year

CF

C-1

1 C

on

cen

trat

ion

[p

mo

l/kg

]

CFC-11 Actual

CFC-11 Theoretical

Indian Ocean CFC-12Indian Ocean CFC-12CFC-12 Actual and Theoretical Concentrations Vs. Time

Nov-87

Dec-87

Jul-95

Feb-96

Jan-95

Jun-95

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

Feb-86 Jul-87 Nov-88 Mar-90 Aug-91 Dec-92 May-94 Sep-95 Feb-97

Year

CF

C-1

2 C

on

cen

trat

ion

[p

mo

l/kg

]

CFC-12 Actual

CFC-12 Theoretical

Future WorkFuture Work

• Calculate CFC-12 Actual and Theoretical Calculate CFC-12 Actual and Theoretical Concentrations over time for same region Concentrations over time for same region and compareand compare

• Seasonal averages from Indian Ocean; Seasonal averages from Indian Ocean; would produce more accurate results as would produce more accurate results as well as possible information about CFC well as possible information about CFC saturation differences between different saturation differences between different times of yeartimes of year

Future Work (cont.)Future Work (cont.)

• Repeat process on different areas around Repeat process on different areas around Indian Ocean with time overlap to achieve Indian Ocean with time overlap to achieve a more complete viewa more complete view

• Repeat for other bodies of water, such as Repeat for other bodies of water, such as the North Atlantic or South Pacific Oceansthe North Atlantic or South Pacific Oceans