subroutine step_plumes(uplume,vplume,thplume,splume,dt,
     .  Nxplumes,Nyplumes,Nr,Nsx,Nsy,bi,bj,
     .                                 duplume,dvplume,dthplume,dsplume)
c-----------------------------------------------------------------------
c Routine to step plumes state forward using the increments 
c
c-----------------------------------------------------------------------
       implicit none
#include "CPP_OPTIONS.h"                                                               
       integer Nxplumes,Nyplumes
       integer Nr,Nsx,Nsy,bi,bj
       _RL uplume(Nxplumes,Nyplumes,Nr,Nsx,Nsy)
       _RL vplume(Nxplumes,Nyplumes,Nr,Nsx,Nsy)
       _RL thplume(Nxplumes,Nyplumes,Nr,Nsx,Nsy)
       _RL splume(Nxplumes,Nyplumes,Nr,Nsx,Nsy)
       _RL duplume(Nxplumes,Nyplumes,Nr,Nsx,Nsy)
       _RL dvplume(Nxplumes,Nyplumes,Nr,Nsx,Nsy)
       _RL dthplume(Nxplumes,Nyplumes,Nr,Nsx,Nsy)
       _RL dsplume(Nxplumes,Nyplumes,Nr,Nsx,Nsy)
       _RL dt
c
       integer i,j,L

       do L = 1,Nr
        do j = 1,Nyplumes
        do i = 1,Nxplumes
         uplume(i,j,L,bi,bj) = uplume(i,j,L,bi,bj) + 
     .                              duplume(i,j,L,bi,bj) * dt
         vplume(i,j,L,bi,bj) = vplume(i,j,L,bi,bj) + 
     .                              dvplume(i,j,L,bi,bj) * dt
         thplume(i,j,L,bi,bj)=thplume(i,j,L,bi,bj) + 
     .                              dthplume(i,j,L,bi,bj)* dt
         splume(i,j,L,bi,bj) = splume(i,j,L,bi,bj) + 
     .                              dsplume(i,j,L,bi,bj) * dt
        enddo
        enddo
       enddo

       return
       end