& ptracer_half , ptracer_full
_RL ptracer_half(nSx,nSy), ptracer_full(nSx,nSy)
ptracer_half(bi,bj) = 0.
ptracer_half(bi,bj) = ptracer_half(bi,bj)+DDTT
& ptracer_half, Nr, bi, bj, myThid )