Boreholes

Paleoclimatology

Lee Jaejoon

Where does the data come from?

From the Earth!US, Canada, Britain, Africa, China, Russia, Australia

What kinds of useful data does it produce? And identify some data it does not produce.

Provides• Vertical timeline of past

climates• annual record of tempera-

ture, precipitation, atmo-spheric composition, vol-canic activity, and wind patterns

• Local wind patterns• environmental conditions

when the snow formed• Advance an retreat of

glaciers.

Doesn’t Provide• What types of organ-

isms lived in the past.

How do you “use” this method Water Wells

• Soil must be soft.• Metal rings support

the soil to avoid col-lapse

• First pound a pipe with weight

• A drill is rotated

Ice Caps

-The cutting pipe has sharp teeth-A motor rotates the pipe -Fingers pop out to keep the ice cap enclosed in the pipe.-The Pipe is lifted

How do we inter-pret the boreholes?(icecaps)Annual snow layers can be seen in the ice caps. The thick-ness difference shows the an-nual amount of snow and the layers differ between summer and winter due to the snow melting from the sun. The ratio of oxygen isotopes shows the temperature.An ultra-precise thermometer is also used to find the tem-perature. This method give a rough data of the trend of temperature. Particles that were in the air get trapped in ice caps and we can see particles such as vol-canic dust, smoke and pollen.

How do we interpret the boreholes? (Disturbing Factors)

• Variation of surface temperature in 2m

• Variation of annual temperature in 20m

• Surface topography, vegetation and hydro-logical conditions affect the subsurface temper-ature.

• Groundwater conditions create uncertainty.

How do we interpret the bore-holes?• Temperature changes in

surface soil occur due to conduction, a direct heat transfer.

• Scientists are able to calcu-late the rate it takes for temperature to change in-side the earth to find the temperature.

• A thermometer or a cable with lots of temperature sensors can be used.

Borehole Site: CA-001-0

0 100 200 300 400 500 600 7000

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Temperature VS Depth Below Surface

Depth below surface (m)

축Tem

pera

ture

(°C

)