PRO SUB_SURFACE_CORRECT_AK19, region, TYPE, INARRAY, OUTARRAY, SURFI
	;locate water surface and correct data array
	;TYPE is type of surface algorithm
		;0 is peak detection
		;1 is maximum slope
		;>1 is peak/100 + TYPE samples to get peak near surface
		;<0 is shitf array using -TYPE as SURFI
	;INARRAY is initial array
	;OUTARRAY is corrected array
	;SURFI is surface sample number
	inarray2 = reform(inarray)
	SLOPE = FLTARR(2000)
	if region eq 'sea' then OUTARRAY = FLTARR(506) else OUTARRAY = fltarr(1335)
	
	if type eq 0 then begin
	 surf = max(inarray,surfi)
	 
	endif

	;IF TYPE EQ 0 THEN BEGIN
	;  background = mean(inarray2[1900:1999])
	;  high_signal = where(inarray2 gt 10*background)   ; high_signal[-1] is last value
	;  if high_signal[0] lt 500 then surfi = 0 else begin
	;	  SURF = MAX(INARRAY[high_signal[-1]-fix(30.0/0.1089):high_signal[-1]], SURFI)
  ;    SURFI = SURFI + high_signal[-1] - fix(30.0/0.1089)
  ;  endelse
	;ENDIF

	IF TYPE EQ 1 THEN BEGIN
	  FOR J = 2, 1997 DO BEGIN
			SLOPE[J] = mean(INARRAY[J+1:J+2]) - mean(INARRAY[J-2:J-1])
		ENDFOR
	   	SURF = MAX(SLOPE, SURFI)
	ENDIF

	IF TYPE GT 1 THEN BEGIN
		SURF = MAX(INARRAY, SURFI)
		SURFI = SURFI>2
		I = SURFI
		WHILE ((INARRAY[I-1] GT 0.1*INARRAY[SURFI]) $
		  AND (I GT 2)) DO I = I - 1
		SURFI = I + TYPE
	ENDIF

;make sure SURFI is within range of data
	;SURFI = SURFI > 46
	;SURFI = SURFI < 540

	if type lt 0 then surfi = -type
	
	; calculate surface-corrected arrays
	if surfi gt 0 then begin
	 if region eq 'sea' then begin
   FOR I = 0>(46-surfi), 505<(1999-surfi+46) DO BEGIN
  		OUTARRAY[I] = INARRAY[I+SURFI-46]	;starts 46 samples above surface
    ENDFOR
	  endif else begin
	  FOR I = 0, 1334<SURFI DO BEGIN
	    OUTARRAY[I] = INARRAY[SURFI-I] 
	  ENDFOR
	  endelse
	endif
RETURN
END