" /> Measuring the Earth’s Surface Heat Flux - Essay Writing Pros

Measuring the Earth’s Surface Heat Flux

The average heat flux at the Earth’s surface provides important information on the amount of heat being produced in the Earth and the temperature distribution in its interior. In the 1800s it was recognized that the temperature in caves and mines increases with depth. Typical values for this increase are dT/dy = 20 to 30 K km−1. Since the thermal conductivities of near-surface rocks are usually in the range 2 to 3 W m−1 K−1, the heat flow to the surface of the Earth implied by these temperature gradients is, according to Equation (4–1), 40 to 90 mW m−2. It is standard practice to take the upward surface heat flow to be a positive quantity, even though from Equation (4–1), with y measured positive downward, it has a negative value.

Although temperature measurements in caves and mines give approximate values for the near-surface thermal gradient, accurate measurements of the thermal gradient in continental areas require deep drill holes. Deep measurements are necessary because climatic variations in the Earth’s surface temperature, particularly those due to ice ages, influence the temperatures in the near-surface rocks. These effects are considered quantitatively in Section 4–14. In order to reach the steady-state thermal structure, holes must be drilled deeper than about 300 m.

Don't use plagiarized sources. Get Your Custom Essay on
Measuring the Earth’s Surface Heat Flux
Just from $13/Page
Order Essay

The thermal gradient is measured by lowering a thermistor (an accurate electronic thermometer) down the drill hole. Care must be exercised to prevent the circulation of drilling fluid during drilling from affecting the measured gradient. This can be done in either of two ways. Measurements can be made at the bottom of the drill hole during drilling. The drilling fluid does not have time to change the temperature at the bottom of the hole. Alternatively, the temperature log of the hole (the measurement of the temperature as a function of depth) can be carried out some time after drilling has ceased. It usually takes 1 to 2 years for a drill hole to equilibrate to the ambient geothermal gradient. Drill holes are invariably filled with groundwater. It is the temperature of this water that is measured by the thermistor. As long as the water is not flowing, its temperature equilibrates with that of the surrounding rock. However, many drill holes cross aquifers (underground channels of porous rock in which water flows), with the result that water will flow up or down the drill hole if it is not lined and will affect the temperature distribution. From Fourier’s law it is clear that the determination of the heat flux requires a measurement of both the temperature gradient and the thermal conductivity of the rock. The thermal conductivity of rocks can be deter4.3 Measuring the Earth’s Surface Heat Flux 241

Laboratory device for measuring the thermal conductivity of a rock sample mined in the laboratory by subjecting samples cut from drill holes to known heat fluxes and measuring the temperature drops across them. Figure 4–3 is a schematic of one way in which this can be done.

Essay Writing Pros
Calculate your paper price
Pages (550 words)
Approximate price: -

Why Work with Us

Top Quality and Well-Researched Papers

Our writers have been trained on how to handle papers placed by our clients. The writer must read and understand before embarking on writing the papers. In case of any issue that needs clarification, writers are encouraged to ask the client or support.

Professional and Experienced Academic Writers

Our team comprises of the best writers and editors. We do thorough vetting during recruitment to make sure that our writers have the knowledge and experience we aspire in the team.

Free Unlimited Revisions

Our aim is to give the client the best outcome. If for some reason you are not satisfied with the wok done, you can ask the paper to be revised or rewritten. This will be done to your satisfaction with no extra charges.

Prompt Delivery and 100% Money-Back-Guarantee

We have writers who work round the clock. This helps in making sure that all our clients’ papers are delivered on time. If we have issues with the deadline, we will ask for extension. If its not possible, the money is fully refunded.

Original & Confidential

Our clients’ confidentiality is highly respected. We can never disclose our clients’ details to third parties. In the same regard, we strive to give our clients 100% original papers. We do not tolerate plagiarism from our writers.

24/7 Customer Support

Clients can reach us any time of the day, and any day of the week. There is a live chat, email or phone numbers to help in ease of communication.

Try it now!

Calculate the price of your order

Total price:
$0.00

How it works?

Follow these simple steps to get your paper done

Place your order

Fill in the order form and provide all details of your assignment.

Proceed with the payment

Choose the payment system that suits you most.

Receive the final file

Once your paper is ready, we will email it to you.

Our Services

You should never be worried about your papers even in the middle of the night. Our team will work round the clock to deliver.

Essays

Essay Writing Service

We have an able team that can deliver your work in the shortest time possible. The academic level or the type of work should never be a hindrance. Our highly competent support team is always around (24/7) to give you any assistance you may need.

Admissions

Admission Essays & Business Writing Help

Do you need to be admitted in your dream institution but find it challenging to write an admission essay? Our team is in a position to write the best letter that will guarantee you an admission. We do as well write the best business proposals and reports.

Reviews

Editing Support

Writing can be fun and enjoyable when everything has been done right. Writing is not just enough without proper editing and proofreading. We have a team of editors that ensure everything falls in place, whether its issues to do with grammar or referencing styles.

Reviews

Revision Support

Once the paper has been done and submitted, that is not the end of it. You can always ask for amendment or improvement if you feel something has not been done right. Our team of writers and editors will gladly assist you to your satisfaction. Revision is free of charge.