ccccccccccc Data format       
c      The data being read are stored in the array with a dimension 144 X 72 X NT 
c          (longitude by latitude by monthly number)

ccccccccccc Longitude and Latitude    
c      The data grid resolution is 2.5 longitude by 2.5 latitude. Therefore, there are 144 
c      grid boxes in the first latitude zone near the South Pole,then 144 boxes in the next 
c      latitude zone right above it, all the way to the North Pole. There are 72 latitude 
c      zones in all, so the first month contains 144x72 = 10,368 temperatures, then on to 
c      the next month, and so forth.  Longitude starts from 180W to 180E, which means the 
c      first longitude index (nx=1) represents the grid box centered at 178.75W (-178.75), and
c      so fourth; and the last longitude index (nx=144) represents the box centered at 178.75E.
c      Please also use "lat.txt" and "lon.txt" files for specific values for the lad/lon definition. 
      
ccccccccccc Time 
c       NT = 441 for ch1, ch2, and ch3 starting from 1978.11 to 2015.07
         
c 	please chekc the NT acccording to the ending date     
c	compile:   f77  -ffixed-line-length-150 -ff77 read_data_monthly.f


         PARAMETER    ( missing = -9999.0 )
         PARAMETER    ( nx=144, ny=72, nt=441) 


c      nx is the longitude(nx =1 for -178.75, nx=2 for -178.75+2.5....,and nx=144 for 178.25)
c      ny is the latitude (ny=1 for 88.75S, ny=2 for 88.75S+2.5,..., and ny=72 for 88.75N)
c      nt is time (see the explanation above) 


         REAL*4      ssu_ch1(nx,ny,nt)
         REAL*4      ssu_ch2(nx,ny,nt)
         REAL*4      ssu_ch3(nx,ny,nt)        
            

         CHARACTER*180   filename

         filename='NOAA-STAR_TCDR_TMS_Merged_SSU1_AMSUA-Eqv_Montnly_S197811-E201512_V3.0.txt'
         OPEN ( 88, file=filename, status='old' )
         PRINT*,"reading! ch1 ............"
	 do k=1,nt
	    do j=1,ny
	     READ ( 88,'(144(f10.3,1x))')(ssu_ch1(i,j,k),i=1,nx)
	  enddo
        enddo
	    
         CLOSE( 88 )

         filename='NOAA-STAR_TCDR_TUS_Merged_SSU2_AMSUA-Eqv_Montnly_S197811-E201512_V3.0.txt'
         OPEN ( 88, file=filename, status='old' )
         PRINT*,"reading! ch2............"
	 do k=1,nt
	    do j=1,ny
	         READ ( 88,'(144(f10.3,1x))')(ssu_ch2(i,j,k),i=1,nx)
	    enddo
	 enddo
         CLOSE( 88 )

         filename='NOAA-STAR_TCDR_TTS_Merged_SSU3_AMSUA-Eqv_Montnly_S197811-E201512_V3.0.txt'
         OPEN ( 88, file=filename, status='old' )
         PRINT*,"reading! ch3 ............"
	  do k=1,nt
	    do j=1,ny
	         READ ( 88,'(144(f10.3,1x))')(ssu_ch3(i,j,k),i=1,nx)
   	    enddo
	 enddo
         CLOSE( 88 )

cccccccccccc We test some number 
         PRINT*, 'ssu_ch1(100, 32, 100)', ssu_ch1(100, 32, 100)
         PRINT*, 'ssu_ch2( 13, 60, 240)', ssu_ch2( 13, 60, 240)
         PRINT*, 'ssu_ch3(130, 45, 90)', ssu_ch3(130, 45, 90)
	 

ccccc you should get the following output: 
c	reading! ch1 ............
c	reading! ch2............
c	reading! ch3 ............
c	 ssu_ch1(100, 32, 100)  226.087006
c	 ssu_ch2( 13, 60, 240)  227.421997
c	 ssu_ch3(130, 45, 90)  249.990005


c    you are ready to go !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 
         END