diff --git a/physics/module_mp_thompson.F90 b/physics/module_mp_thompson.F90
index 2478f828c..c23b6d1d8 100644
--- a/physics/module_mp_thompson.F90
+++ b/physics/module_mp_thompson.F90
@@ -1288,11 +1288,11 @@ SUBROUTINE mp_gt_driver(qv, qc, qr, qi, qs, qg, ni, nr, nc,     &
          rand2 = 0.0
          rand3 = 0.0
          if (rand_perturb_on .ne. 0) then
-            if (MOD(rand_perturb_on,2) .ne. 0) rand1 = rand_pert(i,j)
+            if (MOD(rand_perturb_on,2) .ne. 0) rand1 = rand_pert(i,1)
             m = RSHIFT(ABS(rand_perturb_on),1)
-            if (MOD(m,2) .ne. 0) rand2 = rand_pert(i,j)*2.
+            if (MOD(m,2) .ne. 0) rand2 = rand_pert(i,1)*2.
             m = RSHIFT(ABS(rand_perturb_on),2)
-            if (MOD(m,2) .ne. 0) rand3 = 0.25*(rand_pert(i,j)+ABS(min_rand))
+            if (MOD(m,2) .ne. 0) rand3 = 0.25*(rand_pert(i,1)+ABS(min_rand))
             m = RSHIFT(ABS(rand_perturb_on),3)
          endif
 !+---+-----------------------------------------------------------------+