Comprehensive Ocean Atmosphere Data Set (COADS) (DSI-1169, DSI-1170)

Comprehensive Ocean Atmosphere Data Set (COADS) consists of the historical digital data sets DSI-1169 and DSI-1170, archived at the National Climatic Data Center (NCDC). In the late 19th century, many maritime countries began the task of keying the vast array of ship logbooks which had accumulated over the years onto punch cards. Unfortunately, very little coordination among maritime countries existed during that time, resulting in each data set being keypunched in an entirely different format, and with different coding practices. In the 1940s and 1950s, the United States began acquiring these sets of historical ship observations. As each collection of punch cards was received, it was assigned a unique three digit number called a card deck or deck number. When these data were received by the United States and converted into a common format, random or systematic errors crept into the database. In the 1960s, it was decided to convert all these independent card decks into one common format (DSI-1100). By the late 1960s, over fifteen independent card decks were at NCDC totaling over 30 million ship observations. Each card deck had certain unique characteristics and observing methods. In January 1981, a cooperative project was planned to create a consistent and easily used historical record of surface marine data for the period 1854-1979 (Woodruff, et al., 1987). Members of this project were the National Climatic Data Center (NCDC), Environmental Research Laboratories, the cooperative Institute for Research in Environmental Sciences, and the National Center for Atmospheric Research. The culmination of four years of work resulted in the Comprehensive Ocean-Atmosphere Data Set (COADS) (Slutz, et al., 1985, hereafter referred to as COADS Release 1). One of the many products of COADS was a unique set of surface marine ship reports in a modified DSI-1129 format covering the period 1854-1979 (DSI-1170). This document provides information only for COADS pre-1970s surface marine data. A similar COADS product covering the period 1970-1979 (DSI-1129) is described in a Marine Data Users Reference, 1970-current (NCDC, 1986). Data Prior to 1854 is contained in the Maury collection. Errors and discrepancies exist in the marine data base because of varying quality of the input sources, changes in observing practices, coding practices, and data processing procedures throughout the history of data collection. Whenever possible, flags and indicators have been provided to signal or alleviate some of the problems. THESE FLAGS AND INDICATORS SHOULD BE CAREFULLY EXAMINED BEFORE ANY DATA ARE USED IN ANY TYPE OF STUDY. Global marine data observed during 1854-1979, primarily by ships of opportunity, have been collected, edited, and summarized statistically for each month of the period, using 2 degree latitude x 2 degree longitude boxes. Products now available in a first release from this Comprehensive Ocean- Atmosphere Data Set (COADS) include fully quality-controlled (trimmed) reports and summaries. Each of the 70 million unique reports contain 28 elements of weather, position, etc., as well as flags indicating which observations were statistically trimmed. The summaries give L4 statistics, such as the median and mean, for each of the eight observed variables of air and sea surface temperatures, wind, presssure, humidity, and cloudiness, plus LL derived variables. Relatively noisy (untrimmed) individual reports and summaries (giving L4 statistics for each of the eight observed variables) are available for investigators who prefer their own quality control. Two other report forms, inventories, and decade-month summaries are among the other products available.