From Ocean Teacher Library
History of Chemical Measurement UnitsContents |
Background
In this table only the currently accepted basic SI units (dm3, cm3, mol) are displayed, although the literature is filled with other written expressions of the same concepts. Here are the necessary definitions:
- l = liter = dm3
- milliliter = ml = cm3
- mol = A mole is the amount of pure substance containing the same number of chemical units as there are atoms in exactly 12 grams of C12 (i.e., 6.023 X 1023)
- equivalent = mole (for alkalinity only)
- u = multiplier, of value 10-6; also called "micro"; the Greek letter μ is sometimes used
- m = multiplier, of value 10-3; also called "milli"
Major Systematic Uses of Units for Marine Station Data
| Parameter (click on each variable for additional information) | The Oceans - Sverdrup, Johnson and Fleming, 1942 | World Ocean Database (1994, 1998, 2001, and 2005) | WOCE Hydrographic Program (1990's) |
| Ammonium | umol/dm3 | umol/dm3 | umol/kg |
| Chlorophyll | mg/m3 | ug/dm3 | ug/kg |
| Depth | | m | dbars |
| Nitrate, Nitrite, Phosphate, Silicate | umol/dm3 | umol/dm3 | umol/kg |
| Oxygen | mmol/dm3 | cm3/dm3 | umol/kg |
| pH | Unitless | Unitless | Unitless |
| Salinity | g/kg signified as ‰ | PSU (not really a "unit" but widely referred to as such) | PSS-78 (also not really a unit) |
| Temperature | °C | °C | °C (ITS-90) |
| Alkalinity | | milli-equivalents/dm3 | umol/kg |
Subsections of this Article
No subsections available
Information about this article
Short title: History of Units
Description: none
Expertise level: beginner
Author: Murray.Brown
Approval status: approved
Approved by: Murray.Brown
Last change: 2010-4-16
Subsection of: Chemical Oceanographic Measurements
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