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Hydrophone Data Retrieval Center
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Read This Before Selecting Data Files

The NOAA T-Phase data are organized into 1-Day files. Their file names will reflect the Hydrophone General Location, Year and Julian Date of the data. This can be used for selecting the data files of interests. The data format of these 1-Day NHP (NOAA HydroPhone) data files is list in the NHP Internal Format page.

Structure of the NHP File Name
The NHP file name in general is as follows: 

H##[N/S]xxx[E/W]YrDay[A/B/..../Y/Z].nhp
where ## and xxx are integers for latitude and longitude in degrees respectively; Yr is Year in '99' = Year 1999 and '00' = Year 2000 etc.; Day is day of year in 001 to 366 or Julian Date; and the nhp is the file name's suffix to indicate it is the NOAA Hydrophone data file.

The first part of the file name H##[N/S]xxx[E/W] shows the general location of the Hydrophone. The "N" or "S" and "E" or "W" will be used to indicate the positions of the latitude and longitude. Yr and Day indicate the Date of the data.

The time range of data is indicated by a letter "A" to "Z" after YrDay. When the letter "Z" is shown, the NHP file is a 1-Day file from time 00:00:00 to 23:59:59. For the NHP files with the letters "A" to "Y", they are not a whole day files. For the NHP file with the letter "A", the data are from the beginning of the date, 00:00:00 to some time before the NHP file with the letter "B" (if it exists) of the same Year and Day. For the NHP file with the letter "Y", the data are from some time after the end time of the NHP file with the letter "X" (if it exists) of the same Year and Day to the end of the day, 23:59:59. For the other NHP files with the letters "B" to "X" of the same Year and Day. Their times are in between the end time of file with "A" and the start time of the file with "Y". The general view of the NHP file's time range is

     H*YrDayA.nhp < H*YrDayB.nhp < ... < H*YrDayX.nhp < H*YrDayY.nhp
   00:00:00 to t1   t1   to   t2         tn-1  to  tn   tn to 23:59:59
   where t1 to tn are time in between 00:00:00 and 23:59:59

     1-Day File:      H*YrDayZ.nhp
           from 00:00:00   to   23:59:59
In most cases, only the NHP files with "Z", "A" and "Y" will be found, and few files with "B" also exist. When the NHP files with the letters "A" and "Y" of the same day and year are used, there is a time (data) gap during that day.

Examples of the NHP File Names

H16N049W99362Z.nhp is a 1-Day file of Year 1999 Julian Date 362 at the general location of 16oN and 49oW.
H16N049W00057A.nhp and H16N049W00057Y.nhp show two data files of the same day with a time gap after time 00:00:00 and before 23:59:59.
H08S110W02111Z.nhp another 1-Day file of Year 2002 Julian Date: 111 from a different location.

Select NHP Data Files

The following links point to the ftp sites that contain the NHP data files. Choose a location of interest and select a NHP data file to down load. Note that since the Year is represented by 2 digits, e.g. "99" for 1999 and 00 for 2000, NHP data files for 1999 may be shown at the bottom of screen.

East Pacific Rise Array 1999 to 2002
Time Ranges and Data Gaps

All 6 hydrophones from May 1996 to first half of 1997 plus some 1998 data.
All 6 hydrophones from May 1998 to November 2001.
All 7 hydrophones from November 2000 to November 2002.
where "6 hydrophones" means All phones except the one at 12N095W.

Note that the time ranges indicated above are approximation only. Some the hydrophones may not have data within those ranges, and Some data files may be placed at the next link.

Map of the EPR Array General Locations
Gulf of Alaska Array October 1999 to July 2002
Time Ranges and Data Gaps. 
57N 151W (2000)
56N 151W (2000)
54N 145W (1999-2000)
52N 157W (1999-2000, 2000-2001)
52N 140W (1999-2000, 2000-2001, 2001-2002)
51N 152W (2000)
50N 149W (1999-2000)
50N 145W (1999-2000, 2000-2001, 2001-2002)
50N 135W (1999-2000, 2000, 2001-2002)
Map of the GoA Array General Locations
Mid-Atlantic Ridge Array February 1999 to April 2004
Time Ranges and Data Gaps. 

35N 043W  32N 035W
26N 050W  26N 040W
16N 049W  16N 043W
Map of the MAR Array General Locations

Other Methods to Select Data:
By Event Arrival Times, By Time Range

Convert 1-Day Files into the WAV Format
An IDL program: ConvertNHP2WAV.pro is available to be down loaded for converting the 1-Day Files in the NOAA Internal Format to the WAV format.

Request
If you use the data in publications, please acknowledge the NOAA/ PMEL Acoustics Project Office, Wood Hole Oceanographic Institution, and Lamont-Doherty EarthObservatory. Also, we would appreciate receiving a preprint and/or reprint of those publications utilizing the data for inclusion in the NOAA Acoustics Project bibliography. Relevant publications should be sent to: Dr. Robert Dziak
NOAA Vents Program, 2115, SE OSU Drive, Newport, Oregon 97365.
Acknowledgements
The MAR and EPR data were made available online through grants from the
NSF Logo National Science Foundation (OCE-0137164)
and the
Comprehensive Test-Ban Treaty Organization (contract #01/2/20/258).
Both projects are also supported by the NOAA/ PMEL Vents Program.