Campbell Scientific CR10 CR10 Measurement and Control - Page 147

PARAM. NUMBER TDAYTAPE 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 sTH ORDER POLYNOMIAL *** FUNCTION Evaluate a Sth order polynomialof the form F(X)=Qga g 1 X+C2X2+C3X3*O4X4..O5X5 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 coetficient is limited to a range of t.00001 to t99999. 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 modily coefficients which are very close to 0 to increase the number of significant digits. PARAM. NUMBER TDAYTAPE 01: 2 02: 4 03: 4 04: FP 05: FP 06: FP 07: FP 08: FP 09: FP DESCRIPTION Repetitions IREPSI X Starting inPut location for txl Dest. input location for F(X) [F(X) or Z] C0 coefficient [C0] Cl coefficient ICll C2 coefficient l0zl C3 coefficient tOal C4 coetficient tC4) C5 coetficient [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 presst)re," J. Appl. Meteor, 16, 100-103. Saturation vapor pressure over ice (SVPI) in kilopascals for a OoC 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. NUMBER TDAYTAPE 01: 4 DESCRIPTION Input location of air temperature oC rrEMP.l o2: 4 Destination input location for saturated vapor pressure IVP or Zl Input locations altered: 1 *** 57 VAPOR PRESSURE FROM *** WET./DRY.BU LB TEMPERATURES FUNCTION Calculate vapor pressure in kilopascals from wet and dry-bulb temperatures in "C. This atgorithm type is used by the NationalWeather Service: VP = VPW - A(1 + B.TWXTA - TW) P VP = ambient vapor pressure in kilopascals VPW = saturation vapor pressure at the wetbulb 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