diff --git a/decode/qlook.py b/decode/qlook.py
index 0bfa305..83c2cb9 100644
--- a/decode/qlook.py
+++ b/decode/qlook.py
@@ -208,7 +208,8 @@ def daisy(
                 kwargs={"fill_value": "extrapolate"},
             )
         )
-        da_sub = da_on - da_base.values
+        t_atm = da_on.temperature
+        da_sub = t_atm * (da_on - da_base) / (t_atm - da_base)
 
         # make continuum series
         weight = get_chan_weight(da_off, method=chan_weight, pwv=pwv)