The U.S. Maury Collection (1796 1861), further denoted as MC, has been digitized in China during the years 1993 1996 by the China National Oceanographic Data Center (CNODC) in Tianjin. Approximately 1.4 million records of ship observations, with a vast majority after 1850, were digitized and added to the International Comprehensive Ocean Atmosphere Data Set (ICOADS; NCDC, 1998). The MC includes 523 historical ship’s weather logs stored in the National Archives and Records Administration (NARA) in Washington D.C. The logs mainly originate from the United States and the United Kingdom. However, appendix I gives a complete overview of the logs in the MC originating from other maritime countries. The original logbooks were copied onto 88 reels of microfilm to facilitate preservation of the paper logbooks (NARA, 1986). From these microfilms oversized paper copies were produced which were digitized in China. In addition, the logbooks are also available as digital images. Before being translated to the ICOADS data format (LMR6 = Long Marine Report, version 6) all digitized observations were processed through a series of quality control steps.
The MC partly covers a period where observation procedures and instruments were not standardized. The First International Marine Conference at Brussels in 1853 recommended for the first time accurate and carefully compared instruments for the use of meteorological observations on board of ships. Prior to the conference, observation procedures and instruments were not standardized, particularly between different countries.
Mariners were mainly triggered by the fluctuations of the meteorological instruments, as these indicated changes in weather. The absolute values related to the accuracy of the instruments, did not receive much attention. Scattered remarks in the logs may provide additional metadata and information on instrumental accuracy. Anecdotal evidence on how well the observers carried out their observations can sometimes be found as notes and remarks in the logs.
Historical logbooks like those of the MC are difficult to digitize, especially in a production mode where speed is a major factor for the data entry workers. Despite preliminary preparations and analysis to get the Maury logs ready for digitizing, it became clear that important metadata concerning the observation procedures and the type or scales of the instruments was not always recognized and consequently not entered in the digitized records (Elms, 1999). Bad handwriting and the inability to recognize what the observer had intended to convey, introduced gaps and errors in the metadata because it took too much time to make sense of some of the hardly readable remarks.
To complete the sparse metadata available from the MC, we tried to make sense of all the notes and remarks originally written by the logbook keepers. This work was facilitated by the availability of the digital images of the logbooks via the Internet with the aid of a NOAA application named WSSRD (Web Search Store Retrieve Display), recently replaced by a commercial product called EDADS (Environmental Document Access and Display System). Scrutinizing copies of the original logbook pages significantly enhanced the availability of undiscovered metadata.
In this report we describe the results of the search for metadata in all the logbooks used for the digitization of the MC. We present an overview of historical observing practices included in antique seaman’s handbooks, together with the important logbook remarks for each ship separately. By assembling both the handbook procedures and the logbook remarks, we were able to compile a significant set of historical marine meteorological metadata. The resulting documentation can be used as a future example for digitizing ships’ logbooks or for reprocessing historical marine datasets like the MC.
H Wallbrink, FB Koek, T Brandsma. The US Maury Collection Metadata 1796-1861
KNMI number: PUBL-225, Year: 2009, Pages: 59