Assignment 1
De Bremaecker (1985) gives two versions of the International Gravity Formula.
(1)
(2) 
Equation (1) above is the 1967 International Gravity Formula and equation (2) is the 1930 IGF. Both yield g0 in SI units (meters, kilograms, seconds). The standard geophysical unit for ‘g’ is the milligal, equal to .001 Gal, a unit of acceleration (named after Galileo) equal to 1 cm/s2.
Your assignment:
Calculate and plot g0 (in milligals) as a function of latitude θ from the South Pole to the North Pole. Latitudes south of the equator are, of course, negative.
Calculate and plot the difference between the 1967 and 1930 formulas (in milligals) as a function of latitude over the same range.
Calculate and plot how ‘g’ changes as a function of latitude (
)
over the same range in milligals/degree, for both the 1967 and the 1930 IGF..
Recall your basic spreadsheet procedures: filling cells with a series of equally space numbers, writing and equation using absolute and relative cell references, copying and pasting equations, and setting up charts. Charts should include appropriate labels, well designed axes (no latitude values south of the South Pole or north of the North Pole) and so on. A link to EEES 2500 has remained open for anyone who needs to review Excel. Recall that trigonometric functions in Excel require radians, not degrees, as arguments, but that professors like to see the latitude axis labeled degrees, not radians. Please hand in 3 charts, each with your name.
When comparing 2 equations over the same range, it is usually useful displaying them on the same chart (if they lie on top of one another they are apparently quite close).
Due Monday, August 29, at 9 AM.
Note that when using computers, you can calculate values for many independent variable values with little additional effort. In other words, use a 1 degree sampling interval. I plan to be in for office hours Tuesday AM in case you require coaching in Excel.