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SECTION 10. PROCESSING INSTRUCTIONS
10-5
PARAM. DATA
NUMBER TYPE DESCRIPTION
01: 4 Number of values to
move
02: 4 1st source location
03: 2 Step of source
04: 4 1st destination location
05: 2 Step of destination
Intermediate storage: 0
*** 55 5TH ORDER POLYNOMIAL ***
FUNCTION
Evaluate a 5th order polynomial of the form
F(X)=C0+C1X+C2X
2
+C3X
3
+C4X
4
+C5X
5
where C0 through C5 are the coefficients for
the argument X raised to the zero through fifth
power, respectively. The magnitude of the user
entered coefficient is limited to a range of
±.00001 to ±99999. Polynomials with
coefficients outside this range can be modified
by pre-scaling the X value by an appropriate
factor to place the coefficients within the entry
range. Pre-scaling can also be used to modify
coefficients which are very close to 0 to
increase the number of significant digits.
PARAM. DATA
NUMBER TYPE DESCRIPTION
01: 2 Repetitions [REPS]
02: 4 Starting input location
for X [X]
03: 4 Dest. input location for
F(X)
[F(X) or Z]
04: FP C0 coefficient [C0]
05: FP C1 coefficient [C1]
06: FP C2 coefficient [C2]
07: FP C3 coefficient [C3]
08: FP C4 coefficient [C4]
09: FP C5 coefficient [C5]
Input locations altered: 1* Reps
*** 56 SATURATION VAPOR PRESSURE
***
FUNCTION
Calculate saturation vapor pressure (over water
SVPW) in kilopascals from the air temperature
(°C) and place it in an input location. The
algorithm for obtaining SVPW from air
temperature (°C) is taken from: Lowe, Paul R.:
1977, “An approximating polynomial for
computation of saturation vapor pressure,” J.
Appl. Meteor, 16, 100-103.
Saturation vapor pressure over ice (SVPI) in
kilopascals for a 0°C to -50°C range can be
obtained using Instruction 55 and the
relationship
SVPI = -.00486 + .85471 X + .2441 X
2
where X is the SVPW derived by Instruction 56.
This relationship was derived by Campbell
Scientific from the equations for the SVPW and
the SVPI given in Lowe's paper.
PARAM. DATA
NUMBER TYPE DESCRIPTION
01: 4 Input location of air
temperature °C
[TEMP.]
02: 4 Destination input
location for saturated
vapor pressure
[VP or Z]
Input locations altered: 1
*** 57 VAPOR PRESSURE FROM ***
WET-/DRY-BULB TEMPERATURES
FUNCTION
Calculate vapor pressure in kilopascals from
wet and dry-bulb temperatures in °C. This
algorithm type is used by the National Weather
Service:
VP = VPW - A(1 + B*TW)(TA - TW) P
VP = ambient vapor pressure in kilopascals
VPW = saturation vapor pressure at the wet-
bulb temperature in kilopascals
TW = wet-bulb temperature, °C
TA = ambient air temperature, °C
P = air pressure in kilopascals
A = 0.000660
B = 0.00115