[WP][FEATURE] (stf_issue12): provide noise in simulated observations

src/ts/wf/testcases/Makefile.soutifu

@@ -45,6 +45,10 @@ clean:
 # produce synthetic shot gathers, using refmet
 # ============================================
 #
+# This section provides synthetic seismograms. Model files defined in variable
+# MODELS are supported. Waveforms are simulated by the reflectivity method as
+# implemented in refmet.
+#
 MODELS=2lay.par 2layb.par
 
 # source configuration
@@ -98,11 +102,16 @@ synthetic2lay.sff synthetic2layb.sff syntheticseismo.sff:
 	$(MAKE) new$@ -f Makefile.soutifu
 	/bin/cp -vpd new$@ $@
 
+# add noise
+NOISEAMP=0.
+noisy%.sff: synthetic%.sff 
+	printf "noi  $(NOISEAMP)\nend\n" | tidofi -v -o -cs $@ $<
+
 # apply a filter, simulating a source time function
 STFPER=0.04
 STFFAC=0.1
 stf.fil.xxx: ; printf "lpb  $(STFPER),4\ndel  0.03\nfac  $(STFFAC)\nend\n" > $@
-data%.sff: synthetic%.sff stf.fil.xxx
+data%.sff: noisy%.sff stf.fil.xxx
 	tidofi -v -o -cf $(word 2,$^) $@ $<
 
 # ======================================================================