Development is described of a Comprehensive Ocean-Atmosphere Data Set (COADS)-the result of a cooperative project to collect global weather observations taken near the ocean's surface since 1854, primarily from merchant ships, into a compact and easily used data set. As background, a historical overview is given of how archiving of these marine data has evolved from 1854, when systematic recording of shipboard meteorological and oceanographic observations was first established as an international activity. Input data sets used for COADS are described, as well as the processing steps used to pack input data into compact binary formats and to apply quality controls for identification of suspect weather elements and duplicate marine reports. Seventy-million unique marine reports for 1854-1979 were output from initial processing. Further processing is described, which created statistical summaries for each month of each year of the period, using 2° latitude X 2° longitude boxes. Monthly summary products are available giving 14 statistics (such as the median and the mean) for each of eight observed variables (air and sea-surface temperatures, scalar and vector wind, pressure, humidity, and cloudiness), plus 11 derived variables. Examples of known temporal, spatial, and methodological inhomogeneities in marine data, and plans for periodic updates to COADS, including an update through 1986 scheduled for completion by early 1988, are presented.

Interest in global climate change has risen dramatically during the last several years. In a similar fashion, the number of data sets available to study global change has also increased. Unfortunately, these data sets have been compiled by mal_y different organizations/researchers, making it confusing and time consuming for individual researchers to acquire the "best" data. In response to this _apid growth in the number of global data sets, the Carbon Dioxide Information Analysis Center (CDIAC) and the National Climatic Data Center (NCDC) commenced the Global Historical Climatology Network (GHCN) project. The purpose of this project is to compile an improved global base-line data set of long-term monthly mean temperature, precipitation, sea level pressure, and station pressure for a dense network of worldwide meteorological stations. Specifically, the GHCN project seeks to consolidate the numerous preexisting national-, regional-, and global-scale data sets into a single global climate data base that can be updated, enhanced, mad distributed at regular intervals. The first version of the GHCN data base was completed during the summer of 1992. lt conr,tins 6039 temperature, 7533 precipitation, 1883 sea level pressure, and 1873 station pressure stations. Ali stations have at least 10 years of data, 40% have more than 50 years of data, and 10% have more than 100 years of data. "l_e majority of stations have fairly complete records (72% are missing less than 10% of their data). Furthermore, 80% of ali station records continue into the 1980s or 1990s. Spatial coverage is good over most of the globe, particularly for the United States and central Europe. In comparison to other major global data sets, dramatic improvements are evident over South America, Africa, and Asia. The GHCN data base has been subjected to a large amount of quality control. For example, ali impossibly extreme values have been set to missing. In addition, ali stations (some 17,000) were plotted and visually inspected for "gross" data processing errors and discontinuities, ali of which are documented in the data base itself. At this point, the GHCN data base is considered to be one of the best long-term climate data sets available for the study of global climate change. Furthermore, the data base will continue to evolve in the coming years. Planned improvements entail tile inclusion of additional data, the correction of erroneous data, the adjustment of data inhomogeneities, the addition of new variables, and the production of gridded data sets. The GHCN data base is available as a Ntuneric Data Package (NDP) from CDIAC. The NDP consists of this docmnent and two magnetic tapes that contain machine-readable data files :-and accompanying retrieval codes. This document describes, in detail, both the GHCN data base and the contents of the magnetic tapes.

A new source of cloud and sunshine data, in conjunction with an inspection of the observing practices, instruments, and daily temperature range over the United States, are used to confirm or contradict the large increases of cloudiness previously reported. This analysis indicates that changes in observing practices are primarily responsible for the reported increase of cloudiness during the first half of the this Century. The response of the sunshine instruments and the surface daily temperature range over the United States are not consistent with the reported increases during the first half of this Century. Since the late 1940s however, the increase of cloud cover is confirmed by an inspection of the sunshine data, daily temperature range, changes in instruments, and the instructions to the observers. The types of changes in the cloud observing practices during the late 1930s and 1940s would tend to lead to increases in reported cloud amounts. Although we have not yet produced a combined sunshine/cloudiness index of cloud cover over the Twentieth Century, some cogent inferences can be made at this time: Monotonic trends of cloudiness on the Century time‐scale do not exist in the United States. Fewer clouds were present during the 1930s and early 1950s. There has been a tendency toward increased since 1948.

On May 23, 1972, the United States and the USSR established a bilateral initiative known as the Agreement on Protection of the Environment. The primary goal of the initiative, which remains active despite the breakup of the USSR, is to promote cooperation between the two countries on numerous environmental protection issues. Currently, the agreement fosters joint research in at least 11 "Working Groups" (i.e., areas of study). Given recent interest in possible greenhouse gas-induced climate change, Working Group VIII (Influence of Environmental Changes on Climate) has become particularly useful to the scientific communities of both nations. Among its many achievements, Working Group VIII has been instrumental in the exchange of climatological information between the principal climate data centers of each country [i.e., the National Clirnatic Data Center (NCDC) in Asheville, North Carolina, and the Research Institute of Hydrometeorological Information in Obninsk, Russia]. Considering the relative lack of climate records previously available for the USSR, data obtained via this bilateral exchange are particularly valuable to researchers outside the former Soviet Union. To expedite the dissemination of these data, NOAA's Climate and Global Change Program funded the Carbon Dioxide Information Analysis Center (CDIAC) and NCDC to distribute one of the more useful archives acquired through this exchange: a 223-station daily data set covering the period 1881-1989. This data set contains: (1) daily mean, minimum, and maximum temperature data; (2) daily precipitation data; (3) station inventory information (WMO No., name, coordinates, and elevation); (4) station history information (station relocation and rain gauge replacement dates); and (5) quality assurance information (i.e., flag codes that were assigned as a result of various data checks). The data set is available, free of charge, as a Numeric Data Package (NDP) from CDIAC. The NDP consists of 18 data files and a printed document; which describes both the data files and the 223-station network in detail.

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