APPENDICES
211
APPENDICES
Conversion Factors
Length (L):
Systeme International (SI) base unit: meters (m)
Dimensions: L
1 centimeter (cm)
= 10-2 m = 10-5 km = 0.3937 inch = 0.03281 ft = 0.01094 yd = 6.214 H 10-6 mi
1 meter (m)
= 102 cm = 10-3 km = 39.37 inches = 3.281 ft = 1.094 yd = 6.214 H 10-4 mi
1 kilometer (km)
= 105 cm = 103 m = 3.937 H 104 inches = 3281 ft = 1094 yd = 0.6214 mi
1 inch
= 2.540 cm = 0.02540 m = 2.540 H 10-5 km = 0.08333 ft = 0.02778 yd
= 1.578 H 10-5 mi
1 foot (ft)
= 30.48 cm = 0.3048 m = 3.048 H 10-4 km = 12 inches = 0.3333 yd
= 1.894 H 10-4 mi
1 yard (yd)
= 91.44 cm = 0.9144 m = 9.144 H 10-4 km = 36 inches = 3 ft = 5.682 H 10-4 mi
1 statute mile (mi)
= 1.609 H 105 cm = 1609 m = 1.609 km = 6.336 H 104 inches = 5280 ft = 1760 yd
1 Angstom (D)
= 10-8 cm = 10-10 m
1 micron (F)
= 10-4 cm = 10-6 m
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APPENDICES
1 millimicron (mF)
= 10-7 cm = 10-9 m
1 mil
= 10-3 inch
Area (A):
Systeme International (SI) base unit: square meters (m2)
Dimensions: L2
1 square centimeter (cm2)
= 10-4 m2 = 10-10 km2 = 10-8 ha = 0.1550 inch2 = 1.076 H 10-3 ft2
= 1.196 H 10-4 yd2 = 3.861 H 10-11 mi2 = 2.471 H 10-8 acre
1 square meter (m2)
= 104 cm2 = 10-6 km2 = 10-4 ha = 1550 inches2 = 10.76 ft2
= 1.196 yd2 = 3.861 H 10-7 mi2 = 2.471 H 10-4 acre
1 square kilometer (km2)
= 1010 cm2 = 106 m2 = 102 ha = 1.550 H 109 inches2
= 1.076 H 107 ft2 = 1.196 H 106 yd2 = 0.3861 mi2 = 247.1 acres
1 hectare (ha)
= 108 cm2 = 104 m2 = 10-2 km2 = 1.550 H 107 inches2
= 1.076 H 105 ft2 = 1.196 H 104 yd2 = 3.861 H 10-3 mi2 = 2.471 acres
1 square inch (inch2)
= 6.452 cm2 = 6.452 H 10-4 m2 = 6.452 H 10-10 km2 = 6.452 H 10-8 ha
= 6.944 H 10-3 ft2 = 7.716 H 10-4 yd2 = 2.491 H 10-10 mi2 = 1.594 H 10-7 acre
1 square foot (ft2)
= 929.0 cm2 = 0.09290 m2 = 9.290 H 10-8 km2 = 9.290 H 10-6 ha
= 144 inches2 = 0.1111 yd2 = 3.587 H 10-8 mi2 = 2.296 H 10-5 acre
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1 square yard (yd2)
= 8361 cm2 = 0.8361 m2 = 8.361 H 10-7 km2 = 8.361 H 10-5 ha
= 1296 inches2 = 9 ft2 = 3.228 H 10-7 mi2 = 2.066 H 10-4 acre
1 square mile (mi2)
= 2.590 H 1010 cm2 = 2.590 H 106 m2 = 2.590 km2 = 259.0 ha
= 4.014 H 109 in2 = 2.788 H 107 ft2 = 3.098 H 106 yd2 = 640.0 acres
1 acre
= 4.047 H 107 cm2 = 4047 m2 = 4.047 H 10-3 km2 = 0.4047 ha
= 6.273 H 106 in2 = 4.356 H 104 ft2 = 4840 yd2 = 1.563 H 10-3 mi2
Volume (V):
Systeme International (SI) base unit: cubic meters (m3)
Dimensions: L3
1 cubic centimeter (cm3)
= 10-6 m3 = 10-3 liter = 0.06102 inch3 = 3.531 H 10-5 ft3
= 0.03381 fl oz = 2.642 H 10-4 gal
1 cubic meter (m3)
= 106 cm3 = 103 liters = 6.102 H 104 inches3 = 35.31 ft3
= 3.381 H 104 fl oz = 264.2 gal = 9.729 H 10-3 acre-inch
1 liter
= 103 cm3 = 10-3 m3 = 61.03 inches3 = 0.03532 ft3 =33.81 fl oz = 0.2642 gal
= 0.2270 U.S. dry gallon = 1.057 U.S. fluid quarts = 0.9081 U.S. dry quart
= 0.02838 bu
1 cubic inch (inch3)
= 16.39 cm3 = 1.639 H 10-5 m3 = 0.01639 liter = 5.787 H 10-4 ft3
= 0.5541 fl oz = 4.329 H 10-3 gal
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APPENDICES
1 cubic foot (ft3)
= 2.832 H 104 cm3 = 0.02832 m3 = 28.32 liters = 1728 inches3
= 957.5 fl oz = 7.481 gal
1 U.S. fluid oz (fl oz)
= 29.57 cm3 = 2.957 H 10-5 m3 = 0.02957 liter = 1.805 inches3
= 1.044 H 10-3 ft3 = 7.813 H 10-3 gal = 2.755 H 10-4 acre-inch
1 U.S. fluid gallon (gal)
= 3785 cm3 = 3.785 H 10-3 m3 = 3.785 liters = 231 inches3
= 0.1337 ft3 = 128 fl oz = 8 U.S. fluid pints = 4 U.S. fluid quarts
= 3.683 H 10-5 acre inch
1 U.S. bushel (bu)
= 35.24 liters = 0.3524 hectoliter = 64 U.S. dry pints
= 32 U.S. dry quarts = 9.309 gal. = 8 U.S. dry gallons = 4 U.S. dry pecks
1 acre-inch
= 102.8 m3 = 2.715 H 104 gal = 3630 ft3
Mass (m):
Systeme International (SI) base unit: kilogram (kg)
Dimensions: M
1 gram (g)
= 10-3 kg = 10-5 q = 10-6 metric ton = 6.852 H 10-5 slug
= 0.03527 oz = 2.205 H 10-3 lb = 2.205 H 10-5 cwt = 1.102 H 10-6 U.S. short ton
1 kilogram (kg)
= 103 g = 10-2 q = 10-3 metric ton = 0.06852 slug
= 35.27 oz = 2.205 lb = 0.02205 cwt = 1.102 H 10-3 U.S. short ton
1 metric ton
= 106g = 103 kg = 10 q = 68.52 slugs = 3.527 H 104 oz
= 2205 lb = 22.05 cwt = 1.102 U.S. short tons
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1 slug
= 1.459 H 104 g = 14.59 kg = 0.1459 q = 0.01459 metric ton
= 514.8 oz = 32.17 lb = 0.3217 cwt = 0.01609 U.S. short ton
1 avoirdupois ounce (oz)
= 28.35 g = 0.02835 kg = 2.835 H 10-4 q = 2.835 H 10-5 metric ton
= 1.943 H 10-3 slug = 0.0625 lb = 6.25 H 10-4cwt = 3.125 H 10-5 U.S. short ton
1 avoirdupois pound (lb)
= 453.6 g = 0.4536 kg = 4.536 H 10-3 q = 4.536 H 10-4 metric ton
= 0.03108 slug = 16 oz = 10-2 cwt = 5 H 10-4 U.S. short ton
1 short hundredwight (cwt)
= 4.536 H 104 g = 45.36 kg = 0.4536 q = 0.04536 metric ton
= 3.108 slugs = 1600 oz = 102 lb = 0.05 U.S. short ton
1 U.S. short ton
= 9.072 H 105 g = 907.2 kg = 9.072 q = 0.9072 metric ton =
= 62.16 slugs = 3.2 H 104 oz = 2000 lb = 20 cwt
Density (ρ):
Systeme International (SI) base unit: mass/volume (kg/m3)
Dimensions: ML-3
1 gram per cubic centimeter (g/cm3)
= 103 kg/m3 = 1.940 slugs/ft3 = 0.03613 lb/inch3 = 62.43 lb/ft3
1 kilogram per cubic meter (kg/m3)
= 10-3 g/cm3 = 1.940 H 10-3 slug/ft3 = 3.613 H 10-5 lb/inch3 = 0.06243 lb/ft3
1 slug per cubic foot (slug/ft3)
= 0.5154 g/cm3 = 515.4 kg/m3 = 0.01862 lb/inch3 = 32.17 lb/ft3
1 pound per cubic inch (lb/inch3)
= 27.68 g/cm3 = 2.768 H 104 kg/m3 = 53.71 slugs/ft3 = 1728 lb/ft3
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APPENDICES
1 pound per cubic foot (lb/ft3)
= 0.01602 g/cm3 = 16.02 kg/m3 = 0.03108 slug/ft3 = 5.787 H 10-4 lb/inch3
Velocity (V):
Systeme International (SI) base unit: meter/second (m/s)
Dimensions: Lt-1
1 centimeter per second (cm/sec)
= 10-2 m/sec = 0.036 km/hr = 0.03281 ft/sec = 0.02237 mi/hr = 0.01944 knot
1 meter per second (m/sec)
= 102 cm/sec = 3.6 km/hr = 3.281 ft/sec = 2.237 mi/hr = 1.944 knots
1 kilometer per hour (km/hr)
= 27.78 cm/sec = 0.2778 m/sec = 0.9113 ft/sec = 0.6214 mi/hr = 0.5400 knot
1 foot per second (ft/sec)
= 30.48 cm/sec = 0.3048 m/sec = 1.097 km/hr = 0.6818 mi/hr = 0.5925 knot
1 mile per hour (mi/hr or mph)
= 44.70 cm/sec = 0.4470 m/sec = 1.609 km/hr = 1.467 ft/sec = 0.8690 knot
1 nautical mile/hr (knot)
= 51.44 cm/sec = 0.5144 m/sec = 1.852 km/hr = 1.688 ft/sec = 1.151 mi/hr
Force (F):
Systeme International (SI) base unit: newton (nt or N)
Dimensions: MLt-2
1 dyne
= 10-5 nt = 2.248 H 10-6 lb
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1 newton (nt)
= 105 dynes = 0.2248 lb
1 pound (lb)
= 4.448 H 105 dynes = 4.448 nt
Pressure (p):
Systeme International (SI) base unit: newton/area (nt/m2)
Dimensions: ML-1t-2
1 dyne per square centimeter [barye] (dyne/cm2)
= 10-1 nt/m2 = 1.450 H 10-5 lb/inch2 = 2.089 H 10-3 lb/ft2 = 9.869 H 10-7atm
= 10-6 bar = 10-3mb = 4.015 H 10-4 inch H2O = 7.501 H 10-5 cm Hg
1 newton per square meter [pascal] (nt/m2)
= 10 dynes/cm2 = 1.450 H 10-4 lb/inch2 = 0.02089 lb/ft2 = 9.869 H 10-6 atm
= 10-5 bar = 10-2mb = 4.015 H 10-3 inch H2O = 7.501 H 10-4 cm Hg
1 pound per square inch (lb/inch2 or psi)
= 6.895 H 104 dynes/cm2 = 6.895 H 103 nt/m2 = 144 lb/ft2
= 0.06805 atm = 0.06895 bar = 68.95 mb = 27.68 inches H2O = 5.171 cm Hg
1 pound per square foot (lb/ft2)
= 478.8 dynes/cm2 = 47.88 nt/m2 = 6.944 H 10-3 lb/inch2 = 4.725 H 10-4 atm
= 4.788 H 10-4 bar = 0.4788 mb = 0.1922 inch H2O = 0.03591 cm Hg
1 atmosphere (atm)
= 1.013 H 106 dynes/cm2 = 1.013 H 105 nt/m2 = 14.70 lb/inch2
= 2116 lb/ft2 = 1.013 bars = 1013 mb = 406.8 inches H2O = 76 cm Hg
1 bar
= 106 dynes/cm2 = 105 nt/m2 = 14.50 lb/in2 = 2089 lb/ft2 = 0.9869 atm = 103 mb
= 401.5 inches H2O = 75.01 cm Hg
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APPENDICES
1 millibar (mb)
= 103 dynes/cm2 = 102 nt/m2 = 0.01450 lb/inch2 = 2.089 lb/ft2
= 9.869 H 10-4 atm = 10-3 bar = 0.4015 inch H2O = 0.07501 cm Hg
1 inch of water at 4EC (inch H2O)
= 2491 dynes/cm2 = 249.1 nt/m2 = 0.03613 lb/inch2 = 5.202 lb/ft2
= 2.458 H 10-3 atm = 2.491 H 10-3 bar = 2.491 mb = 0.1868 cm Hg
1 centimeter of mercury at 0EC (cm Hg)
= 1.333 H 104 dynes/cm2 = 1333 nt/m2 = 0.1934 lb/inch2 = 27.85 lb/ft2
= 0.01316 atm = 0.01333 bar = 13.33 mb = 5.353 inches H2O
Energy (E):
Systeme International (SI) base unit: joule (J = nt m)
Dimensions: ML2t-2
1 erg
= 10-7 joule = 2.778 H 10-14 kw hr = 7.376 H 10-8 ft lb
= 3.725 H 10-14 hp hr = 2.389 H 10-8 cal = 9.485 H 10-11 Btu
1 joule
= 107 ergs = 2.778 H 10-7 kw hr = 0.7376 ft lb
= 3.725 H 10-7 hp hr = 0.2389 cal = 9.485 H 10-4 Btu
1 kilowatt hour (kw hr)
= 3.6 H 1013 ergs = 3.6 H 106 joules = 2.655 H 106 ft lb
= 1.341 hp hr = 8.601 H 105 cal = 3415 Btu
1 foot pound (ft lb)
= 1.356 H 107 ergs = 1.356 joules = 3.766 H 10-7 kw hr
= 5.051 H 10-7 hp hr = 0.3239 cal = 1.286 H 10-3 Btu
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1 horsepower hour (hp hr)
= 2.685 H 1013 ergs = 2.685 H 106 joules = 0.7457 kw hr
= 1.98 H 106 ft lb = 6.413 H 105 cal = 2546 Btu
1 calorie at 15EC (cal)
= 4.186 H 107 ergs = 4.186 joules = 1.163 H 10-6 kw hr = 3.087 ft lb
= 1.559 H 10-6 hp hr = 3.970 H 10-3 Btu
1 British thermal unit (Btu)
= 1.054 H 1010 ergs = 1054 joules = 2.929 H 10-4 kw hr
= 777.6 ft lb = 3.928 H 10-4 hp hr = 251.9 cal
Power (P):
Systeme International (SI) base unit: watt (J/s)
Dimensions: ML2t-3
1 watt [1 joule per second]
= 10-3 kw = 0.7376 ft lb/sec = 44.25 ft lb/min
= 1.341 H 10-3 hp = 0.2389 cal/sec = 3.414 Btu/hr
1 kilowatt (kw)
= 103 watts = 737.6 ft lb/sec = 4.425 H 104 ft lb/min
= 1.341 hp = 238.9 cal/sec = 3414 Btu/hr
1 foot pound per second (ft lb/sec)
= 1.356 watts = 1.356 H 10-3 kw = 60 ft lb/min
= 1.818 H 10-3 hp = 0.3239 cal/sec = 4.629 Btu/hr
1 foot pound per minute (ft lb/min)
= 0.02260 watt = 2.260 H 10-5 kw = 0.01667 ft lb/sec = 3.030 H 10-5 hp
= 5.398 H 10-3 cal/sec = 0.07716 Btu/hr
1 horsepower (hp)
= 745.7 watts = 0.7457 kw = 550 ft lb/sec
= 3.300 H 104 ft lb/min = 178.1 cal/sec = 2546 Btu/hr
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APPENDICES
1 calorie per second (cal/sec)
= 4.186 watts = 4.186 H 10-3 kw = 3.087 ft lb/sec
= 185.2 ft lb/min = 5.613 H 10-3 hp = 14.29 Btu/hr
1 British thermal unit per hour (Btu/hr)
= 0.2929 watt = 2.929 H 10-4 kw = 0.2160 ft lb/sec = 12.96 ft lb/min
= 3.928 H 10-4 hp = 0.06997 cal/sec
Temperature (T):
Systeme International (SI) base unit: Kelvin (K)
Dimensions: T
Degrees Celcius (EC)
= K - 273 = (5/9)(EF - 32)
Kelvin (K)
= EC + 273 = (5/9)(EF - 32) + 273
Degrees Fahrenheit (EF)
= (9/5)EC + 32 = (9/5)(K - 273) + 32
Yield:
1 kilogram per hectare (kg/ha)
= 10-3 metric ton/ha = 0.8922 lb/acre = 8.922 H 10-3 cwt/acre
= 4.461 H 10-4 short ton/acre
1 metric ton per hectare (metric ton/ha)
=103 kg/ha = 892.2 lb/acre = 8.922 cwt/acre = 0.4461 short ton/acre
1 pound per acre (lb/acre)
= 1.121 kg/ha =1.121 H 10-3 metric ton/ha = 10-2 cwt/acre
= 5 H 10-4 short ton/acre
1 hundredweight per acre (cwt/acre)
= 112.1 kg/ha = 0.1121 metric ton/ha = 100 lb/acre = 0.05 short ton/acre
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1 short ton per acre (short ton/acre)
= 2242 kg/ha = 2.242 metric ton/ha = 2000 lb/acre = 20 cwt/acre
1 liter per hectare (liter/ha)
= 10-2 hl/ha = 0.01148 bu/acre
1 hectoliter per hectare (hg/ha)
= 102 liters/ha = 1.148 bu/acre
1 U.S. bushel per acre (bu/acre)
= 87.08 liters/ha = 0.8708 hl/ha
Flow (Q) :
Systeme International (SI) base unit: meter3/sec (m3/s)
Dimensions: L3t-1
1 cubic centimeter per second (cm3/sec)
= 10-3 liter/sec = 0.06 liter/min = 3.531 H 10-5 ft3/sec = 2.119 H 10-3 ft3/min
= 2.642 H 10-4 gal/sec = 0.01585 gal/min
1 liter per second (liter/sec)
= 103 cm3/sec = 60 liters/min = 0.03532 ft3/sec
= 2.119 ft3/min = 0.2642 gal/sec = 15.85 gal/min
1 liter per minute (liter/min)
= 16.67 cm3/sec = 0.01667 liter/sec = 5.886 H 10-4 ft3/sec = 0.03532 ft3/min
= 4.403 H 10-3 gal/sec = 0.2642 gal/min
1 cubic foot per second (ft3/sec)
= 2.832 H 104 cm3/sec = 28.32 liters/sec = 1699 liters/min = 60 ft3/min
= 7.481 gal/sec = 448.8 gal/min = 0.9917 acre-inch/hr
1 cubic foot per minute (ft3/min)
= 471.9 cm3/sec = 0.4719 liter/sec = 28.32 liters/min = 0.01667 ft3/sec
= 0.1247 gal/sec = 7.481 gal/min = 0.01653 acre-inch/hr
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APPENDICES
1 U.S. fluid gallon per second (gal/sec)
= 3785 cm3/sec = 3.785 liters/sec = 227.1 liter/min = 0.1337 ft3/sec
= 8.021 ft3/min = 60 gal/min
1 U.S. fluid gallon per minute (gal/min)
= 63.09 cm3/sec = 0.06309 liter/sec = 3.785 liter/min = 2.228 H 10-3 ft3/sec
= 0.1337 ft3/min = 0.01667 gal/sec
Dynamic (absolute) Viscosity (µ):
Systeme International (SI) base unit: (nt s /m2)
Dimensions: ML-1t-1
1 slug/ft s = 1 lb s/ft2 = 47.88 kg/m s = 47.88 N s/m2
1 poise = 1 dynes s/cm2 = 0.1 N s/m2
Kinematic Viscosity (v):
Systeme International (SI) base unit: meter2/sec (m2/s)
Dimensions: L2 t-1
1 ft2/s = 0.0929 m2/s
1 stoke = 1 cm2/s = 0.00108 ft2/s
1 m2/s = 10.764 ft2/s
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Selected Physical Constants
cpa
Specific heat capacity of dry air = 1.003 H 107 ergs/gEC = 1003 joules/kgEC
= 0.2396 cal/gEC
e
Base of the natural logarithms = 2.71828
FN
Faraday constant = 96,500 coulombs per gram equivalent
g
Acceleration of gravity: normal acceleration = 980.665 cm/sec2 =9.80665 m/sec2 =
32.1740 ft/sec2
k
von Karman constant = about 0.41 (unitless)
L
Latent heat of vaporization of water:
at 0EC = 2.494 H 1010 ergs/g = 2.494 H 106 joules/kg = 595.9 cal/g
at 20EC = 2.448 H 1010 ergs/g = 2.448 H 106 joules/kg = 584.9 cal/g
at 100EC = 2.259 H 1010 ergs/g = 2.259 H 106 joules/kg = 539.55 cal/g
NA
Avogadro=s number = 6.023 H 1023 molecules/mole
Pa
Pressure of the atmosphere: standard atmosphere = 1.01325 H 106 dynes/cm2 =
1.01325 H 105 nt/m2 = 14.69 lb/inch2 = 2117 lb/ft2
R*
Universal gas constant (gas constant per mole) = 8.314 H 107 ergs/K mole =
8.314 joules/K mole = 1.986 cal/K mole
RN
Solar constant = 1.35 H 106 ergs/cm2 sec = 1.35 H 103 watts/m2 = 1.94 cal/cm2 min
(langleys/min)
γ
Psychrometric constant at 1 standard atmosphere and 20EC = 0.667 mb/K =
0.278 mm Hg/EF
ε
Ratio of the molecular weight of water to that of air = 0.622 (unitless)
ρa
Density of dry air: at 1 standard atmosphere and 0EC = 1.293 H 10-3 g/cm3 =
1.293 kg/m3 = 2.508 H 10-3 slug/ft3
ρw
Density of water: maximum density at 1 standard atmoshphere and 3.98EC =
0.99997 g/cm3 = 1.00000 g/ml
ρHg
Density of mercury: at 1 standard atmosphere and 0EC = 13.595 g/cm3 =
13,595 kg/m3 = 26.38 slugs/ft3
π
= 3.14159
σ
Stefan-Boltzmann constant = 5.67 H 10-5 ergs/K4 cm2 sec = 5.67 H 10-8 watts/K4 m2 =
8.127 H 10-11 cal/K4 cm2 min (langley/K4 min)
Boltzmann constant = 1.381 H 10-16 ergs/K = 1.381 H 10-23 joules/K =
3.298 H 10-24 cal/K
Ice point = 273.16 K
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APPENDICES
Properties of Liquid Water
Temperature
Density
3
a
Specificb
Heat
Capacity
Vapor
Pressure
Viscosity
Thermal
Conduc-
Dielectric
Constant
Surface
Tension
tivity
EC
g/cm
J/g K
kPa
FPa s
mW/K m
mN/m
0
0.99984
4.2176
0.6113
1793
561.0
87.90
75.64
10
0.99970
4.1921
1.2281
1307
580.0
83.96
74.23
20
0.99821
4.1818
2.3388
1002
598.4
80.20
72.75
30
0.99565
4.1784
4.2455
797.7
615.4
76.60
71.20
40
0.99222
4.1785
7.3814
653.2
630.5
73.17
69.60
50
0.98803
4.1806
12.344
547.0
643.5
69.88
67.94
60
0.98320
4.1843
19.932
466.5
654.3
66.73
66.24
70
0.97778
4.1895
31.176
404.0
663.1
63.73
64.47
80
0.97182
4.1963
47.373
354.4
670.0
60.86
62.67
90
0.96535
4.2050
70.117
314.5
675.3
58.12
60.82
100
0.95840
4.2159
101.325
281.8
679.1
55.51
58.91
a
All values (except vapor pressure) given for 100 kPa (1bar) pressure.
b
Specific heat capacity at constant pressure (Cp).
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Symbol, Dimensions, and International System (SI) of Units for Soil Water Terms
Term
Symbol
Dimensions
SI Units
Bowen ratio
β
----
(sensible heat flux)/(latent heat
flux)
Chemical potential
µ
L2t-2
J/kg
Cumulative depth of infiltration
I
L
m
Degree of saturation
S
----
(volume water)/(volume fluids)
Depth ratio of soil water
θv
----
(depth water)/(unit depth soil)
Discharge rate
Q
L3t-1
m3/s
Dispersivity
λ
L
m
Distribution coefficient
kd
----
(adsorbed concentration)/
(solute concentration)
Dry bulk density
ρb
ML-3
Mg/m3, g/cm3
Equivalent depth of soil water
De
L
m
Gravitational head
z
L
m
Gravitational potentiala
ψz
ML-1t-2
N/m2, Pa
Heat capacity
c
ML2t-2K-1
J/K
Hydraulic head
H
L
m
Hydraulic potentiala
ψh
ML-1t-2
N/m2, Pa
Hydrodynamic dispersion coefficient
Dh
L2t-1
m2/s
Infiltration rate
I
Lt-1
m/s
Latent heat flux
LEt
Mt-3
W/m2
Liquid dynamic viscosity
η
ML-1t-1
Pa s
Mass water content
θm
----
(mass water)/(mass dry soil)
Matric potentiala
ψm
ML-1t-2
N/m2, Pa
Mean particle density
ρs
ML-3
Mg/m3, g/cm3
RN
Mt-3
W/m2
(Soil water storage)
(Density of solids)
Net radiation
VADOSE ZONE HYDROLOGY/ENVIRONMENTAL SOIL PHYSICS
SPRING 2004
226
APPENDICES
Term
Symbol
k
Dimensions
L2
SI Units
m2
Pore water velocity
v
Lt-1
m/s
Porosity
n
----
(volume fluids)/(total volume)
Pressure potentiala
ψp
ML-1t-2
N/m2, Pa
Retardation factor
R
-----
(change in concentration)/
(change in time)
Saturated hydraulic conductivity
Ks
Lt-1
m/s
Saturated water content
θs
----
(volume water at saturation)/
(total volume)
Sensible heat flux
H
Mt-3
W/m2
Soil thermal conductivity
λ
Mt-3K-1
J/m s K
Soil water head (matric head)
H
L
m
Soil bulk dielectric constant
εb
----
[(propogation velocity in
vacuum)/(propogation velocity
2
in medium)]
Soil heat flux
G
Mt-3
W/m2
Soil water diffusivity
D
Lt-1
m/s
Solute (osmotic) potentiala
ψs
ML-1t-2
N/m2, Pa
Sorptivity
S
Lt-1/2
m/s1/2
Total potentiala
ψT
ML-1t-2
N/m2, Pa
Void ratio
e
----
(volume fluids)/(volume solids)
Volumetric water content
θv
----
(volume water)/(total volume)
Water density
ρw
ML-3
g/cm3
Water vapor pressure
e
ML-1t-2
Pa, N/m2
Water flux density
Jw
Lt-1
m/s
Water vapor potentiala
ψw
ML-1t-2
N/m2, Pa
Permeability
a
Dimensions and units given for volumetric potential (energy per unit volume).
VADOSE ZONE HYDROLOGY/ENVIRONMENTAL SOIL PHYSICS
SPRING 2004