!---------------------------------
Subroutine Calc_Trend_Sen
Integer :: ist, it, it1, ireg, N1, Numyear, imon, imon1
Real :: SenSl, prob
Real :: Wk(Ntime)   ! Chi tinh tu nam thu 2 tro di (bo nam dau tien)

   Numyear=Ntime/2  ! It nhat phai co Numyear thanh phan /= Miss
   Do ist=1, Nst
         Wk(1:Ntime) = PDSI(ist,1:Ntime); 
         Call MK_Sen(Wk,Ntime,NumYear,Miss,SenSl,prob,N1)
         Sen_PDSI(ist) = SenSl; Pro_PDSI(ist) = prob
   Enddo

! Real, Dimension (Nst,Nmon) :: Sen_Mon,  Pro_Mon
! Sen's Slope for each mon

  Numyear=Nyear/4*3
  Do ist=1, Nst
     Do imon=1, Nmon
        it1=0
        Do it=1, Ntime
           imon1=mod(it,Nmon); if (imon1==0) imon1=Nmon
           if (imon1==imon) then
              it1=it1+1; Wk(it1)=PDSI(ist,it)
           endif
        Enddo
        Call MK_Sen(Wk,it1,NumYear,Miss,SenSl,prob,N1)
        Sen_Mon(ist,imon) = SenSl; Pro_Mon(ist,imon) = prob
     Enddo
  Enddo
End Subroutine Calc_Trend_Sen