; Read a priori data file for V3
;
; INPUT: 
;   (none)
; OUTPUT:
;   co_ap: a priori CO profile (35 levels)
;   ch4_ap: a priori CH4 profile (35)
;   pres_ap: pressure levels of profiles (35)
;   covmat_ap: a priori CO covariance matrix (35x35)
;
; L. Emmons, NCAR, 26 July 2001; 13 June 2002
;
;-------------------------------------------------------------------------

pro read_apriori_dat_v3, co_ap, ch4_ap, pres_ap, covmat_ap

sdum=' '

apfile = 'mopitt_v3_apriori.dat'
openr,ilun,apfile,/get_lun
readf,ilun,sdum
readf,ilun,sdum
readf,ilun,nlev

readf,ilun,sdum
pres_ap = fltarr(nlev)
readf,ilun,pres_ap
readf,ilun,sdum
co_ap = fltarr(nlev)
readf,ilun,co_ap
readf,ilun,sdum
ch4_ap = fltarr(nlev)
readf,ilun,ch4_ap

readf,ilun,sdum
covmat_ap = fltarr(nlev,nlev)

for i=0,nlev-1 do begin
 readf,ilun,sdum
 n = i+1
 data1 = fltarr(n)
 readf,ilun,data1
 covmat_ap[i,0:i] = data1
 covmat_ap[0:i,i] = data1
endfor
free_lun,ilun


end