Adverbial noun phrases are NP-ADV.

( (IP-MAT (NP-SBJ *pro*)
	  (NP-ADV (Q-F-P Todas) (D-F-P as) (N-P tardes))
	  (VB-D íamos)
	  (IP-INF (VB merendar))
	  (PP (P a)
	      (NP (D o) (ADJ-G forte)))
	  (, ,))
(TYCHO BRAHE; ID A_003_PSD,19.238))

( (IP-MAT (ADVP (ADV Porém))
	  (, ,)
	  (NP-SBJ (PRO ele))
	  (VB-D repetiu)
	  (NP-ACC (D o) (ADJ mesmo) (N grito))
	  (NP-ADV (Q-P muitas) (N-P vezes))
	  (, ,)
	  (PP (P sem)
	      (CP-ADV (C que)
		      (IP-SUB (NP-SBJ (D o) (N juiz))
			      (NP-DAT (CL lhe))
			      (VB-SD dissesse)
			      (NP-ACC (N palavra)))))
	  (. .))
  (POST SCRIPTUM; ID CARDS0042,.3))

(IP-MAT   (CONJ E)
          (ADVP (ADV depois))
          (NP-SBJ  (D o)
                   (N barco))
          (VB-P-3S navega)
          (NP-ADV  (D-UM um)
                   (N bocadinho))
[...]
(CORDIAL-SIN; ID VPA05)

( (IP-MAT (IP-MAT (NP-SBJ *pro*)
		  (NP-ADV (D Aquel) (N seerãão))
		  (ADVP (ADV depois)
			(CP-ADV (C que)
				(IP-SUB (NP-SBJ *pro*)
					(VB-D comerom))))
		  (VB-D sairom)
		  (PP (P por)
		      (NP (D-UM-F hũa) (N orta)))
		  (PP (P por)
		      (IP-INF (NP-SBJ *pro*)
			      (VB-F folgarem))))
	  (CONJP (CONJ e)
		 (IP-MAT (NP-SBJ (NPR Gallaaz))
			 (VB-D preguntou)
			 (CP-QUE (WNP-1 (WD que) (N uentura))
				 (IP-SUB (NP-SBJ *T*-1)
					 (NP-ACC (CL os))
					 (VB-RA adussera)
					 (ADVP (ADV ali))))))
	  (. .))
  (WOCHWEL; ID DSG47,.8))

 
See also:
Measure NP
Adverbial clauses