1 SUBROUTINE ATMOS (A3,A8,A4) 2C 3C THIS ROUTINE CALCULATES ATMOSPHERIC PROPERTIES OF THE 4C US STANDARD ATMOSPHERE,1962,ASSUMING AN INVERSE SQUARE 5C GRAVITATIONAL FIELD. THIS ASSUMPTION YIELDS DATA THAT 6C AGREES WITH THE COESA DOCUMENT WITHIN 1 PER CENT AT 7C ALL ALTITUDES UP TO 700 KILOMETERS (2296588 FEET). THE 8C DATA IS ARRANGED IN THE ATMOSPHERE ARRAY, A, AS 9C FOLLOWS 10C A(1) = CS, SPEED OF SOUND, FT/SEC 11C A(2) = (1/CS)(DCS/DZ), SOUND DERIVATIVE, 1/FT 12C A(3) = Z, GEOMETRIC ALTITUDE, FT 13C A(4) = P, PRESSURE, LB/FT2 14C A(5) = DP/DZ, PRESSURE DERIVATIVE, LB/FT3 15C A(6) = RHO, DENSITY, SLUGS/FT3 16C A(7) = (1/RHO)(DRHO/DZ), DENSITY DERIVATIVE, 1/FT 17C A(8) = T, TEMPERATURE, DEG RANKINE 18C A(9) = DT/DZ, TEMPERATURE DERIVATIVE, DEG RANKINE/FT 19C 20C VARIOUS CONSTANTS USED 21C EARTH RADIUS = 20890855 FT 22C SPECIFIC HEAT RATIO FOR AIR = 1.4 23C SEA LEVEL VALUES 24C GRAVITATIONAL ACCELERATION = 32.1740484 FT/SEC2 25C MOLECULAR WEIGHT = 28.9644 26C GO*MO/R* = 0.018743418 DEG RANK/FT 27C 28 DIMENSION A( 9),HG(10),ZM(14),WM(14),TM(23),PM(22) 29C 30C SET ARRAYS AND CONSTANT VALUES 31 DATA G0,WM0,R0,GMRS/32.1740484,28.9644,20890855.0, 32 1 0.018743418/,HG/-16404.,0.0 33 2 ,36089.,65617.,104987.,154199.,170604.,200131., 34 3 250186.,291160./,ZM/295276.,328084., 35 4 360892.,393701.,492126.,524934.,557743.,623360., 36 5 754593.,984252.,1312336.,1640420.,1968504., 37 6 2296588./,WM/28.9644,28.88,28.56, 38 7 28.07,26.92,26.66,26.4,25.85,24.7,22.66,19.94, 39 8 17.94,16.84,16.17/ 40C 41 DATA TM/577.17,518.67,389.97,389.97,411.57 42 1 ,487.17,487.17,454.77,325.17,325.17,379.17,469.17 43 2 ,649.17,1729.17,1999.17,2179.17,2431.17,2791.17 44 3 ,3295.17,3889.17,4357.17,4663.17,4861.17/,PM/ 45 4 3711.0839,2116.2165,472.67563,114.34314, 46 5 18.128355,2.3162178,1.2321972,3.8030279E-01, 47 6 2.1671352E-02,3.4313478E-03,6.2773411E-04,1.53490 48 7 91E-04,5.2624212E-05,1.0561806E-05,7.7083076E-06, 49 8 5.8267151E-06,3.5159854E-06,1.4520255E-06,3.92905 50 9 63E-07,8.4030242E-08,2.2835256E-08,7.1875452E-09/ 51C 52 A(3) = A3 53C 54C CALCULATE G, Z, AND CHECK 55C 56 1000 Z = A(3) 57 G = G0*(R0/(R0+Z))**2 58 IF (Z .GT. 295276.0) GO TO 1040 59C 60C TMS LINEAR WITH GEOPOTENTIAL. CALCULATE H AND SEARCH 61C 62 H = R0*Z/(R0+Z) 63 DO 1010 I= 2,10 64 J = I - 1 65 IF (HG(I) .GE. H) GO TO 1020 66 1010 CONTINUE 67C 68C CALCULATE TMS SLOPE,TMS, AND SET MOL WT STUFF 69C 70 1020 ELH = (TM(J+1) - TM(J))/(HG(J+1) - HG(J)) 71 TMS = TM(J) + ELH*(H - HG(J)) 72 ELZ = ELH*G/G0 73 DMDZ = 0.0 74 EM = WM0 75C 76C CHECK TMS SLOPE AND CALCULATE PRESSURE 77C 78 IF (ELH .EQ. 0.0) GO TO 1030 79C 80C NON - ZERO SLOPE PRESSURE EQUATION 81C 82 A(4) = PM(J)*(TM(J)/TMS)**(GMRS/ELH) 83 GO TO 1070 84C 85C ZERO SLOPE PRESSURE EQUATION 86C 87 1030 A(4) = PM(J)*EXP(GMRS*(HG(J)-H)/TMS) 88 GO TO 1070 89C 90C TMS LINEAR WITH Z. SEARCH MATRIX 91C 92 1040 DO 1050 I = 2,14 93 J = I + 8 94 K = I - 1 95 IF (ZM(I) .GE. Z) GO TO 1060 96 1050 CONTINUE 97C 98C CALCULATE TMS, SLOPE, AND STUFF 99C 100 1060 ELZ = (TM(J+1) - TM(J))/(ZM(K+1) - ZM(K)) 101 TMS = TM(J) + ELZ*(Z - ZM(K)) 102 DMDZ = (WM(K+1) - WM(K))/(ZM(K+1) - ZM(K)) 103 EM = WM(K) + DMDZ*(Z - ZM(K)) 104 ZLZ = Z - TMS/ELZ 105C 106C PRESSURE EQUATION FOR TMS LINEAR WITH Z 107C 108 A(4) = PM(J)*EXP(GMRS/ELZ*(R0/(R0+ZLZ))**2*((Z-ZM(K))* 109 1 (R0+ZLZ)/(R0+Z)/(R0+ZM(K)) - ALOG(TMS*(R0+ZM(K) 110 2 )/TM(J)/(R0+Z)))) 111C 112C CALCULATE SOUND SPEED AND DERIVATIVE 113C 114 1070 A(1) = 49.022164*SQRT(TMS) 115 A(2) = 0.5*ELZ/TMS 116C 117C CALCULATE DENSITY, DERIVATIVE, AND PRESSURE DERIVATIVE 118C 119 A(6) = GMRS*A(4)/G0/TMS 120 A(7) = - (A(6)*G/A(4) + ELZ/TMS) 121 A(5) = -A(6)*G 122C 123C CALCULATE TEMPERATURE, DERIVATIVE, AND LEAVE 124C 125 A(8) = EM*TMS/WM0 126 A(9) = (EM*ELZ + TMS*DMDZ)/WM0 127 A8 = A(8) 128 A4 = A(4) 129 A1 = A(1) 130 A6 = A(6) 131 RETURN 132 END 133