Environmental Data Analysis EESC BC 3017

Warm-up

Units and scientific notation

How to present numbers

scientific notation (as opposed to standard notation): coefficient, base, exponent; e.g.: 5.6*10^-7
exponential prefixes for orders of magnitude

Scientific notation

Prefix...........	Exponent	Examples of exponential usage:
peta (P)	15	amount of CO₂ in atmosphere (as C)- 750 Pg (or Gt)
tera (T)	12	storage of a hard disk system - tera bytes
giga (G)	9	pool sizes: amount of water in ocean - 1.37 x 10⁹ km³
mega (M)	6	rates: flow of Anatarctic Circumpolar Current - 200 x 10⁶ m s^-1
kilo (k)	3	distance New York - Albany ~ 350km
hecto (h)	2	atmospheric pressure: ~1012.5 hPa (=1012.5 mbar)
base unit	0
milli (m)	-3	typical amount of medicine ~1ml
micro (m)	-6
nano (n)	-9	wavelength of violet light ~400nm
pico (p)	-12	size of atom ~10pm
femto (f)	-15	detection limit of gas chromatographs for SF₆: ~1 fmole/L

significant digits (you want to be confident with every digit you give)
include units (e.g. km³/y or km³y^-1)

Data without units (except for dimensionless numbers) are useless

the MKS and SI system
Unit conversions
perform unit conversions in a formal way, multiply by "1"
example: conversion of a river discharge rate from cf/s (or ft³/s) into km³/y

⁷

^-9

exercise: convert 5 acre feet into liters (use EXCEL or computer calculator)
exercise: convert the mileage of my car, which is 5.6 L/100km into miles per gallon

"Back of the envelope" (order of magnitude) estimates

Many problems in Environmental Sciences can be assessed in an approximate way by using common sense and some basic ideas about areas, volumes, density, etc. Examples include:

how many dentists are there in NYC?
what is the NYC water consumption

The method is called "back-of-the-envelope-calculations". We will practice this skill:

How many cobblers are there in the United States? Different approaches:

How often do you need a cobbler?
Yellow pages

How many pair of shoes can you make out of one cow (hint: Consider a spherical cow...)?
What is the discharge rate of the Hudson River?

MS Excel and addins

Microsoft Excel (Besides ARCGIS) will be the prime software package we are going to use in this class.
I will only spend a brief period in class to discuss the basics. However there is a lot you can do yourself if you need help (see for example: the office assistant and on-line help within Excel's help menu, the MS website, or Helpresources for Excel
The textbook also has a good introductory overview of Excel and there are help fiiles associated with Excel
We will work through 2 examples in class that will teach you how to download information and perform basic data manipulation

NYC water supply
Ice melt

set up Statplus and analysis tool pack addin
reminder: bring USB flash drives for backup (>1GB)
the Mac version of MS office does not have the 'Analysis tool pack' which we'll need, however you can add most of its functionality by following these instructions