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+C2X2+C3X3+C4X4+C5X5

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

 

SECTION 10. PROCESSING INSTRUCTIONS

***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 X2

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

10-5