diff --git a/env/WCOSS2.env b/env/WCOSS2.env
index e0d2c8ac6c..9fe9179e6b 100755
--- a/env/WCOSS2.env
+++ b/env/WCOSS2.env
@@ -81,7 +81,7 @@ elif [[ "${step}" = "prepobsaero" ]]; then
     nth_max=$((npe_node_max / npe_node_prepaeroobs))
 
     export NTHREADS_PREPOBSAERO=${nth_prepobsaero:-1}
-    export APRUN_PREPOBSAERO="${launcher} -n ${npe_prepobsaero} --cpus-per-task=${NTHREADS_PREPOBSAERO}"
+    export APRUN_PREPOBSAERO="${launcher} -n ${npe_prepobsaero} --ppn ${npe_node_prepobsaero}--cpu-bind depth --depth=${NTHREADS_PREPOBSAERO}"
 
 elif [[ "${step}" = "snowanl" ]]; then