;The procedure getlongterm_theta_wc.pro finds the long term value of the 
;vertical rotation theta given the wind direction phi for sonic anemometer 
;data. It is used by getrotated_wc.pro which is in dayflux_wc.pro.
;The long term value of vertical rotation is based on a fit of hour-long
;averages of the wind direction (phi) and vertical rotation (theta).
;The fitted function has the form
;        theta= amin*sin(phi-omega)+co(3)*phi^3+co(2)*phi^2+co(1)*phi+co(0)
;amin is the maginitude of sine function fitted to the data
;omega is the phase of the sine function
;co are coefficients of a polynomial fit to the residual (resid=data-sine fcn)
;
;Use of this procedure is as follows:
;         getlongterm_theta_wc,year,jday,nphi,nnth
;Where
;          |      year = 4-digit integer year
;    input |      jday = julian day
;          |      nphi = half-hour-long average value of wind direction
;
;   output |      nnth = vertical rotation theta based on fitted curves
;          |             of half hour avg wind direction and vertical rotation
;
;Written by BWBerger 9/27/99 based heavily on getlongterm_theta.pro used for
;wlef.
; Modified by W wang for Lost Creek, Sep 20 2000

pro getlongterm_theta_lc,year,jday,nphi,nnth

if nphi ne -999. then begin


;   if (year eq 1999) and (jday ge ?) and (jday lt ?) then begin
; after getting the amin ,omega and...., need change them 

;         amin=0.066701286
;         omega=-2.5506242
;         co=[0.0090345802,0.0037363508,0.0065523144,-0.00054193522]
;         amin=0.051741764
;         omega=3.1415928
;         co=[-0.00037361167,-0.0035706706,0.0025629113, 0.0399209632]
;  Dec 18, 2000, for 257-289/2000 fit


         amin=0.017511213
         omega=2.9670598
         co=[0.0087165802,-0.0038714996,0.0010906214,0.00042049559]

      IF year EQ 2000 THEN BEGIN
           amin=0.021669309
         omega=3.0836478
         co=[0.0086829844,-0.0018659206,0.0026119162,0.00010596805]
    nnth=amin*sin(nphi-omega)+co(3)*nphi^3+co(2)*nphi^2+co(1)*nphi+co(0)
      ENDIF

     IF year EQ 2001 THEN BEGIN

; 2001   using higher-order fitting, becasue the shape of the theta-phi is a
; little bit strange

        amin=-0.018986855
        omega=-0.17453294
        co=[0.0065484938,-0.0047221532,-0.0012790248,0.0016544594,$
0.0046622083,-0.00022475063,-0.00096655132,1.4160792e-05,5.3013155e-05]

;2002, Mar. 27, using all data of 2001 to do fitting

        amin=0.020322408
        omega=2.6179939
        co=[0.0083716696,-0.0047960443,-0.0022397452,0.0011075278,$
0.0042626141,-7.9092888e-5,-0.00087304430,4.5311606e-05,4.7442026e-05]

    nnth=amin*sin(nphi-omega)+co(8)*nphi^8+co(7)*nphi^7+$
         co(6)*nphi^6+co(5)*nphi^5+co(4)*nphi^4+$
         co(3)*nphi^3+co(2)*nphi^2+co(1)*nphi+co(0)
      ENDIF
        


     IF year EQ 2002 THEN BEGIN
;     Aug. 5th, 2002, run 1-211, 2002

        amin=0.02474787
        omega=2.7925269
        co=[0.0021808224,0.00042482282,-0.00091026390,-0.00026438968,$
    0.0053640759,0.00021799720,-0.0011198411,-2.1259950e-05,6.0010783e-05]
;Jan 17, 2003, run all 2002 data

      amin=0.023466431
      omega=2.4951228
co=[0.0056570107,-0.0037556831,-0.00057394931,0.00050055629,$
    0.0039005290,0.00014904975,-0.00085685088,-1.7902185e-05,4.6805068e-05]

    nnth=amin*sin(nphi-omega)+co(8)*nphi^8+co(7)*nphi^7+$
         co(6)*nphi^6+co(5)*nphi^5+co(4)*nphi^4+$
         co(3)*nphi^3+co(2)*nphi^2+co(1)*nphi+co(0)

     ENDIF


     IF year EQ 2003 THEN BEGIN
;11/3/2003, not a whole year data, using 'mean' option

      amin=0.024978855D
      omega=2.7925269D
co=[-0.0120147600D,-0.0021925211,0.0072136577,0.0038824472 ,$
    0.0014632920,-0.00095999577,-0.00047889008,6.1371553e-05,2.5617064e-05]

;2/21/2004, whole 2003 data, use 'mean' option
      amin=0.022244441D
      omega=2.9670598D
co=[-0.0163717760D,-0.0032206786,0.0088745290,0.0038688867 ,$
    0.0018265567,-0.00091921557,-0.00057803668,5.8782210e-05,3.1308394e-05]


    nnth=amin*sin(nphi-omega)+co(8)*nphi^8+co(7)*nphi^7+$
         co(6)*nphi^6+co(5)*nphi^5+co(4)*nphi^4+$
         co(3)*nphi^3+co(2)*nphi^2+co(1)*nphi+co(0)

     ENDIF

     IF year EQ 2004 THEN BEGIN
;9/4/2004, not a whole year data, using 'mean' option

      amin=0.025120732D
      omega=2.6179939D
co=[-0.0025998531D,0.0032595536,0.0066730443,-0.0019350462,$
    5.2588224e-5,0.00031173895,-0.00023399741,-1.3584004e-5,1.4318307e-5]


;2/1/2005, whole year data, use 'mean' option
      amin=0.022851494d
      omega=2.6179939D
co=[-0.0026632144D,0.0010066403,0.0081829007,-0.0010414222,$
   -0.00073068963,0.00017441855,-0.00011092421,-7.1612000e-6,7.8054867e-6]

    nnth=amin*sin(nphi-omega)+co(8)*nphi^8+co(7)*nphi^7+$
         co(6)*nphi^6+co(5)*nphi^5+co(4)*nphi^4+$
         co(3)*nphi^3+co(2)*nphi^2+co(1)*nphi+co(0)

     ENDIF


     IF year EQ 2005 THEN BEGIN

;02/01/2006, using 8th-order-mean fit, whole year

       amin=-0.020066534
       omega=-0.34906587
       co=[-0.0024739337,0.0021365113,0.00042755346,-0.0013805386,$
     0.0037070591,0.00012974259,-0.00086268110,-1.0062387e-06,4.6713244e-05]

    nnth=amin*sin(nphi-omega)+co(8)*nphi^8+co(7)*nphi^7+$
         co(6)*nphi^6+co(5)*nphi^5+co(4)*nphi^4+$
         co(3)*nphi^3+co(2)*nphi^2+co(1)*nphi+co(0)

     ENDIF

     IF year EQ 2006 THEN BEGIN

;05/06/2007, using 8th-order-mean fit, whole year

       amin=-0.021632015D
       omega=-0.34906587D
       co=[-0.0053641589D,0.0027635196D,0.0046807328D,-0.0019208237D,$
 0.0016357183D,0.00034783700D,-0.00055356098D,-1.8362532D-05,3.2819394D-05]

    nnth=amin*sin(nphi-omega)+co(8)*nphi^8+co(7)*nphi^7+$
         co(6)*nphi^6+co(5)*nphi^5+co(4)*nphi^4+$
         co(3)*nphi^3+co(2)*nphi^2+co(1)*nphi+co(0)

     ENDIF
     

;   nnth=-999. ;this line to be removed when a fit becomes available
endif else begin
   nnth=-999.
endelse

return
end