The "tr055" directory contains 12 files (11 data files plus this documentation file) associated with data described in the DOE Technical Report, TR055: Climate Data Bases of the People's Republic of China, 1841-1988 Dale Kaiser Carbon Dioxide Information Analysis Center Oak Ridge National Laboratory Oak Ridge, Tennessee, U.S.A. Shiyan Tao, Congbin Fu, Zhaomei Zeng, Qingyun Zhang Institute of Atmospheric Physics Chinese Academy of Sciences Beijing, China Wei-Chyung Wang Atmospheric Science Research Center University at Albany State University of New York Albany, New York, U.S.A. Thomas Karl Global Climate Laboratory National Climatic Data Center National Oceanic and Atmospheric Administration Asheville, North Carolina, U.S.A. ***NOTE*** Users of the TR055 data are urged to order the hardcopy documentation of TR055 and the numeric data package that highlights two of the more important Chinese data sets (ORNL/CDIAC-47, NDP-039), both available free of charge from CDIAC (see Sect. 4 below). These documents contain much more information (e.g., maps, tables, and graphs) than is contained in this documentation file. 1. Introduction The United States Department of Energy (DOE) and the People's Republic of China (PRC) Chinese Academy of Sciences (CAS) signed an agreement on August 19, 1987, to carry out a joint research program on possible CO2-induced climate changes. Concern over such climate changes stems from rising atmospheric concentrations of greenhouse gases and the ever-increasing global CO2 emissions from fossil fuel usage (Marland and Boden 1992; Marland 1991; Marland and Rotty 1984). The nature of these phenomena signals the need for international research efforts in the area of possible anthropogenic climate change. The intent of the DOE/CAS research agreement is to contribute to research efforts through the performance of four tasks: (1) analysis of general circulation models (GCMs), (2) preparation and analysis of proxy and instrumental data, (3) study of the relationship between large- and regional-scale climates, and (4) study of possible increases in atmospheric methane (Riches et al. 1992; Koomanoff et al. 1988). Descriptions of these tasks and additional background information on each country's involvement in atmospheric CO2 research may also be found in Riches et al. (1992) and Koomanoff et al. (1988). This report describes five PRC instrumental climate data sets, which were exchanged along with PRC proxy data sets and U.S. instrumental data sets according to the data exchange protocol contained in the DOE/CAS agreement. CAS's Institute of Atmospheric Physics has provided records from 296 stations, organized into five data sets: (1) a 60-station data set containing monthly measurements of barometric pressure, surface air temperature, precipitation amount, relative humidity, sunshine duration, cloud amount, wind direction and speed, and number of days with snow cover; (2) a 205-station data set containing monthly mean temperatures and monthly precipitation totals; (3) a 40-station subset of the 205-station data set containing monthly mean maximum and minimum temperatures and monthly extreme maximum and minimum temperatures; (4) a 180-station data set containing daily precipitation totals; and (5) a 147-station data set containing 10-day precipitation totals. Sixteen stations from these data sets (13 from the 60-station set and 3 from the 205-station set) have temperature and/or precipitation records that begin prior to 1900, whereas the remaining stations began observing in the early to mid-1900s. Records from most stations extend through 1988; however, the daily precipitation data extend only through 1982. These data represent the most comprehensive, long-term instrumental Chinese climate data currently available. A number of studies done in recent years utilized data from the 60- and 205-station data sets. A subset of the monthly mean temperature data contained therein has recently been used in assessing urban heat island effects in eastern China over the period 1954-1983 (Jones et al. 1990; Wang et al. 1990). Vose et al. (1992) used temperature, precipitation, and atmospheric pressure records, and Jones et al. (1985) used temperature records from these data sets in compiling data bases suitable for long-term climate analyses. The precipitation data from the 205-station data set were used by Eischeid et al. (1991) in compiling a comprehensive precipitation data set for global land areas. The 60- and 205-station data sets have been documented in detail by Tao et al. (1991). The intent of this report is to give a descriptive overview of all PRC instrumental climate data received to date by DOE under the DOE/CAS research agreement. They may be used for comparison with the Chinese climate records published in the World Weather Records,* World Monthly Surface Station Climatology (Spangler and Jenne 1990), and Bradley et al. (1985). The spatial and temporal coverage and variety of observation types offered by the five PRC data sets makes this collection a valuable and convenient source of climate data for this part of the world. *Smithsonian Institution (1927, 1934, 1947); U.S. Weather Bureau (1959, 1967); National Environmental Satellite, Data, and Information Service (1981-1983) 2. Description of the PRC Climate Data Sets 2.1 60-Station Network The data from these stations are the broadest in scope of all five data sets. Each record of the data set contains one month's data (column numbers of each variable to the right in parentheses): WMO station number (2-6) year (8-11) month (13-14) mean station pressure (mb) (18-22) mean temperature (C) (26-30) mean maximum temperature (C) (34-38) mean minimum temperature (C) (42-46) total precipitation (mm) (50-54) sunshine duration (h) (58-62) mean cloud amount (percentage of sky cover) (66-70) mean relative humidity (%) (74-78) snow days (days with snow cover) (82-86) dominant wind direction (degrees) (90-94) mean wind speed (m/s) (98-102) dominant wind frequency (%) (106-110) extreme maximum temperature (C) (114-118) extreme minimum temperature (C) (122-126) The data are in the file "sta60.dat". Each data value is given in tenths of its specified unit of measure. Missing data values are indicated by "-9999". Alphabetic codes have in some cases been inserted to flag suspect data values. Their meanings are detailed in Tao et al. (1991) and also in the descriptive file (ndp039.des) found in the ndp039 subdirectory of of CDIAC's anonymous ftp area. Four basic criteria were used in selecting stations to make up the 60-station network: (1) the station should be representative of a particular climate region of China, (2) the station's data should be of relatively high quality, (3) the period of record of the station should be reasonably long, and (4) the resulting station network should have a relatively uniform spatial distribution. An inventory of the selected stations is given in the file "sta60.inv" in this directory. Each record of the file contains the station name and WMO number, latitude and longitude in degrees and minutes, elevation above mean sea level (meters), and the beginning year of record. Thirteen stations began observing before 1900, Beijing's record being the longest, having temperature and precipitation data dating back to 1841. All 60 stations have temperature and/or precipitation data available from the beginning of their periods of record, with other types of observations beginning more randomly with time throughout the network. Records from all stations run through 1988, but extreme maximum and minimum temperature data are available for each station only since 1984. Nearly one-half of the 60 stations have some type of data for at least 70 years, but only 10% have data for 100 years or more. There is little data available for much of the 1940s (centered on 1945 and assumably related to World War II and its aftermath). Data are available from all 60 stations over the period 1951-1988. Whole years for which no data are available have been omitted from the data set. These years/stations are summarized in Tao et al. (1991). Details of data collection methods used at the 60 stations (e.g.,type, orientation, and calibration of instruments; daily observing times; and observational techniques) have been made available by CAS and are contained in Appendix A. Station histories extending through 1983 are available for all 60 stations (Appendix B of Tao et al. (1991)). 2.2 205-Station Network The data from the 205-station network contain two variables; monthly mean temperature (in tenths of degrees Celsius) and total monthly precipitation (in tenths of millimeters), each comprising a separate data set. The data are contained in the files "sta205t.dat" and "sta205p.dat". This network (a subset of which comprises the 40-station network described in Sect. 2.3) has no stations in common with the 60-station network. Alphabetic codes have been inserted in some records of these data sets to flag suspect data values. Their meanings are detailed in Tao et al. (1991) and in the "ndp039.des" file in the subdirectory ndp039 in CDIAC's anonymous ftp area. Each record of a data set contains data from one year: the WMO station number and year, followed by twelve monthly data values. Missing values are represented by "-9999". An inventory of the 205 stations is given in the file "sta205.inv". Each record of the file contains the station name and WMO number, latitude and longitude in degrees and minutes, elevation above mean sea level (meters), and the beginning year of record for temperature and precipitation data, respectively. The temperature data date back to 1907 (Jingzhou, No. 57476), and the precipitation data to 1880 (Wuhu, No. 58334). Temperature and precipitation records from 202 stations extend through 1988. Records from Geershiquanhe (No. 55228), Hekou (No. 56989), and Lingling (No. 57866) extend through 1982, 1980, and 1983, respectively. The most typical length of record for these stations ranges between 30 and 40 years; a relatively small share of stations [29 stations (15%) for temperature data; 24 stations (12%) for precipitation data] having records of 50 years or longer. 2.3 40-Station Network The stations included in this network are a subset of the 205-station network. The data from these stations consist of four monthly variables: mean maximum temperature (C) mean minimum temperature (C) extreme maximum temperature (C) extreme minimum temperature (C) The period of record for all 40 stations is the same: 1984-1988. Each record contains data for one month, with the WMO station number, year and month followed by monthly mean maximum temperature, monthly mean minimum temperature, monthly extreme maximum temperature, and monthly extreme minimum temperature. All temperatures are expressed in tenths of degrees Celsius. The data are found in the file "sta40.dat". An inventory of these 40 stations is contained in the file "sta40.inv". Each record contains the station name and WMO number, latitude and longitude in degrees and minutes, elevation above mean sea level (meters), and the beginning year of record. 2.4 180-Station Network Daily precipitation amounts are available for the stations in this network. The earliest data are from 1951 (91 stations), with all but one of the remaining station records (Da Qaidam, No. 52713, data from 1964) beginning at some time in the 1950s. Data from all stations run through 1982. The first record for each station contains (colum numbers given): WMO station number (2-6) latitude (degrees * 100 + minutes) (9-12) longitude (degrees * 100 + minutes) (14-18) elevation (m) (21-24) beginning year of record (27-30) ending year of record (33-36) length of record (years) (41-42) number of monthly data records for the station (46-48) length of record (days) (50-54) number of days recording precipitation of 0.1 mm or greater (56-60) number of days with no precipitation or less than 0.1mm (not including days when the observation was missing) (62-66) total precipitation over the station's entire period of record (tenths of millimeters) (67-72) The remaining records for each station contain one month's data: WMO station number, year and month are followed by 31 daily precipitation amounts (tenths of mm). Months with fewer than 31 days have a value of -1 assigned to the precipitation amounts for nonexistent days. The 60- and 180-station networks have 53 stations in common; thus, there is significant station history information available (Appendix B, Tao et al. (1991)). Also, information relating to precipitation instrumentation and measurement (Appendix A) applies to the 53 stations. These types of background information are not currently available for the other 127 stations in the network. The station inventory for this network is given in the file "sta180.inv". Each record of the file contains the station name and WMO number, latitude and longitude in degrees and minutes, elevation above mean sea level (meters), and the beginning year of record. 2.5 147-Station Network Ten-day precipitation totals have been compiled for the stations in this network. As with the stations in the 180-station network, their periods of record are relatively short. This network has 120 stations in common with the 180-station network and 45 stations in common with the 60-station network. Therefore, background information for 45 stations is available from Appendices A, B, and C in Tao et al. (1991). The data are in the file "sta147.dat"; each record containing data for one year, with WMO station number and year followed by totals for 36 "10-day" periods. The term 10-day refers to periods consisting of days 1-10, 11-20, and the remaining days of a month. The station inventory for this network is given in the file "sta147.inv". Each record of the file contains the station name and WMO number, latitude and longitude in degrees and minutes, elevation above mean sea level (meters), and the beginning year of record. 3. Quality of the Data Many types of meteorological observations are included in the five PRC data sets described in this report. DOE's Carbon Dioxide Information Analysis Center (CDIAC), located at Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee, has conducted a quality assurance (QA) review of the data, checking them for completeness, reasonableness, and accuracy. Given the large amount and many types of data contained in the PRC data sets as a whole, it is not surprising that CDIAC has found some erroneous and inconsistent values in the data files. In most cases, this pertained to nonprecipitation data from the 60- and 205-station data sets, as all but the most obvious problems (e.g., unrealistically large or repetitive totals) are extremely difficult to discern in precipitation time series. Many data questions were resolved with the help of CAS, whereas in the case of the 60- and 205-station data sets, any remaining questionable data were flagged so that users may treat these data as they see fit (details available in Tao et al. (1991)). Assessments of data quality and descriptions and results of QA checks for each of the PRC data sets are organized in the following sections by data type. 3.1 Station Histories The 60 station histories (Appendix B, Tao et al. (1991)) contain much of the information necessary to determine how a particular station's data may be used in assessing climate trends. They include information regarding station location (city or countryside, elevation, etc.), station moves, times of observation, and published data sources. However, some potentially useful station-specific details are not present. For example, the switch from the Jordan Photographic Sunshine recorder to the Campbell-Stokes Sunshine recorder, which is noted in Appendix A as having occurred in 1954, may not have taken place at all stations simultaneously as implied. Sunshine recorder changes took many years to implement over the entire U.S. sunshine recording network (Steurer and Karl 1991). There is also a lack of documentation regarding daily cloud amount observing schedules, which are provided in only ten of the station histories. Users should be aware that histories for all stations extend only through 1983. Updates will hopefully be available at a future date. Also, it was found that for three stations (Nos. 53463, 58367, and 58633), the data record begins before the period documented by the station history. For three other stations (Nos. 50745, 54527, and 56294), data are not available until several years after the first year documented in the station histories. Finally, barometric pressure data suggest that three station histories (Nos. 57127, 57461, and 57516) lack documentation of station moves (discussed in Sect. 3.2). In summary, 60 stations have histories of sufficient detail to enable confident use of much of their data in climate research. The usefulness of the data from the other 236 stations would be greatly improved if station histories could be made available. 3.2 Monthly Mean Barometric Pressure (60-Station Network) The data seem to show an occasional departure from reporting values to the nearest tenth of a millibar, as evidenced by many occurrences of several (in one case, six) consecutive monthly values containing a zero in the tenths place. Software designed to find deviations from the otherwise characteristic seasonal cycle of monthly mean barometric pressure observed at all 60 stations uncovered evidence of undocumented station moves at Nos. 57127, 57461, and 57516, each having one or more years of pressure data in which the range differed markedly from that for prior or subsequent years. Other single-month values that departed significantly from typical seasonal trends were flagged if not corroborated by data from neighboring stations. 3.3 Temperature Several types of surface air temperature data are contained in three of the five PRC data sets. Their respective QA checks and results are discussed below by station network. 3.3.1 60-Station Network (monthly means of temperature, maximum temperature, and minimum temperature through 1988; monthly extreme maximum and minimum temperatures from 1984-1988) Checks for proper relationships between the various monthly mean/extreme temperatures have been made, and the relatively small number of errors found have been corrected through consultation with CAS. Another simple check involved looking for statistical outliers by calculating the mean and standard deviation of the respective monthly values for the mean temperature variables from each station. Values lying 3.5 or more standard deviations away from the mean of the respective monthly values were flagged if they could not be corroborated by temperatures at neighboring stations. Checking for departures from the characteristic seasonal cycle of monthly mean temperature produced several values that, while not statistical outliers, were also flagged as suspect if they could not be corroborated by monthly temperature trends from neighboring stations. 3.3.2 205-Station Network (monthly means) Temperatures from 40 of these stations from 1984-1988 were checked against their respective extreme and mean maximum/minimum temperatures in the 40-station data set, and several inconsistencies were resolved with the help of CAS. The pre-1984 data could not be checked in this manner; means and standard deviations of each station's monthly values were calculated, and values lying 3.5 or more standard deviations away from their respective means were flagged if they could not be corroborated by temperatures at neighboring stations. Checking for departures from the characteristic seasonal cycle of monthly mean temperature produced several values that, while not statistical outliers, were flagged as suspect if they could not be corroborated by monthly temperature trends from neighboring stations. 3.3.3 40-Station Network (monthly mean/extreme maximum and minimum temperatures for 1984-1988) As described in the preceding, cross-referencing temperatures from these stations with those in the 205-station data set turned up some inconsistencies that were resolved with help from CAS. Extreme and mean maximum and minimum temperatures for years prior to 1984 would be extremely useful, but whether they will become available remains uncertain. 3.4 Precipitation Totals Precipitation data are provided in four of the five PRC data sets. For each, QA checks basically focused on researching very high totals and flagging nonzero totals repeated over consecutive observing periods. Their respective QA checks and results are discussed below by station network. 3.4.1 60-Station Network (monthly) Totals exceeding 500 mm (about 20 in.) were found in 176 cases, and three of these totals exceeded 1m. Practically all of these totals were considered valid; they were received in the warmer half of the year in regions that typically experience monsoonal effects. However, the extremely high totals found in the original CAS data set for LaSa (No. 55591) for May-September of 1936 (486.5, 517.7, 2049.6, 1313.2, and 619.2 mm, respectively) were considered highly suspect and replaced by totals for LaSa obtained from Eischeid et al. (1991). These totals are flagged in the data set and are 48.5, 52.7, 205.0,131.0, and 62.0 mm for May-September, respectively; it appears likely that there was simply a decimal position problem in the PRC data. Several large totals for other stations, while not edited, were also flagged, as were several nonzero identical totals over consecutive months. These data are likely to be very important and useful due to their relatively long periods of record and the availability of station histories. 3.4.2 205-Station Network (monthly) Several hundred totals exceeding 500 mm are present in the data, with three June totals from Heyuan (No. 59293) exceeding 1m. These Heyuan totals and several other especially large totals were researched by CAS and confirmed. All of these large amounts were received in the warmer half of the year in regions that typically experience monsoonal effects. Also, many instances of identical nonzero totals over consecutive months were found in the data and flagged. These data, which in many cases provide relatively long records, would be especially useful if station histories could be documented and made available (which is uncertain at this time). 3.4.3 180-Station Network (daily) Twenty-three totals exceeding 300mm (about 12 inches) are contained in the data. These totals were not researched because they were all received in the summer monsoon/typhoon season in southeastern China. 3.4.4 147-Station Network (ten-day) As noted in the preceding, these data include 113 stations that are also found in the 180-station daily precipitation data set, which provides a means of double checking the 10-day totals via cross-referencing. For the purposes of this QA review, this was only done to confirm, to some degree, the highest totals reported. Totals exceeding 300mm were found to occur 113 times. As with the high daily totals mentioned, the vast majority were received in the summer monsoon season in southeastern China. The high totals found for several more northerly and centrally located stations were also exclusively summertime phenomena. 3.5 Monthly Sunshine Duration (60-Station Network) These data were checked for identical values over consecutive months. This type of occurrence should be relatively rare because the monthly totals are rounded to the nearest tenth of an hour. Forty-nine pairs of months were found where this did occur. These values have been flagged so that users may decide if they appear plausible (perhaps by considering cloud amounts or other data over these months). Monthly maximum possible sunshine duration was calculated for each station by using the station's latitude and assuming a smooth, spherical earth where the sun's rays would not be blocked by natural or man-made obstructions. Using the maximum durations, monthly values of percentage of possible sunshine were calculated for each station and plotted versus corresponding monthly cloud amounts. The plots were examined for obvious outlier data points; ten points were flagged from ten different stations. These values were examined in the context of the range of sun and cloud data for the particular month and station to determine which values were in error. These values were then set to the missing indicator "-9999". Documentation provided by CAS (Appendix A) points out that a significant number of estimates (not identified) are included in these data. 3.6 Monthly Mean Cloud Amount (60-Station Network) In addition to inspecting the data plots described in the preceding, these data were checked for values less than or equal to 0 or equal to or greater than 100%. No values of 0% were found, but four values of 100% were found at four different stations. They are considered reasonable in light of the concurrent values of sunshine duration and relative humidity reported at each station. Documentation provided by CAS (Appendix A) points out that a significant number of estimates (not identified) are included in these data. 3.7 Monthly Mean Relative Humidity (60-Station Network) These data were simply checked for values less than or equal to 0 or equal to or greater than 100%. None were found; the data appeared reasonable upon cursory inspection. 3.8 Monthly Number of Days with Snow Cover (60-Station Network) Monthly variations for stations reporting any days with snow cover seem reasonable, and no values exceeding the number of days in a particular month were found. 3.9 Monthly Dominant Wind Direction and Dominant Wind Frequency (60-Station Network) Inconsistencies have been found in these data. The dominant wind direction is defined in Appendix A as the most frequent wind direction observed for the month, measured in 22.5 degree increments of azimuth clockwise from north. A direction of 0 is used to denote calm winds, and 360 indicates a north wind. The data have been checked to make sure all dominant wind directions (if not set to the missing code "-9999") are 0 or some multiple of 22.5 up to 360. Pre-1981 data show a large number of dominant wind directions with values of 0 , the extent of which varies greatly by individual station. This probably makes good physical sense, as diurnal variations alone in many areas could often be associated with lengthy periods of calm at night. However, all dominant wind directions for 1981-1983 are missing, and there are no values of 0 for any station during the period 1984-1988. This probably implies a change in denoting the dominant wind direction for the period 1984-1988, whereas the reason for missing data for 1981-1983 is unknown. Data prior to 1981 have reasonable values for dominant wind frequency, usually ranging from about 10 to 50%. Frequencies for 1981-1983 are missing due to missing dominant wind direction, as are those for 1984-1988, even though values of unknown character are present for dominant wind direction. Taking these factors into consideration, the pre-1981 data are considered reasonable, but the character of the data thereafter is uncertain. 3.10 Monthly Mean Wind Speed (60-Station Network) These data appear reasonable; values range from 0 to 9.4 m/s. Only one value of 0 m/s was found (for December 1952 at Yi Ning, No. 51431), and because the dominant wind direction is given as 0 (calm), the value has not been researched. (The dominant wind frequency is missing for this month.) 4. How to Obtain the Data All of the PRC climate data sets described in the preceding are available free of charge from CDIAC. The data are available on magnetic tape, floppy diskette, or via CDIAC's anonymous FTP area (see FTP address below). Those ordering the data should also request the numeric data package (NDP), which describes the 60- and 205-station data sets in greater detail (ORNL/CDIAC-47, NDP-039, Two Long-Term Instrumental Climatic Data Bases of the People's Republic of China), also available free of charge. Requests for the data on magnetic tape should include any specific instructions for transmitting the data (e.g., 1600 or 6250 BPI density, labeled or nonlabeled, ASCII or EBCDIC characters, and block size or record length constraints) required by the user to access the data. Requests not accompanied by specific instructions will be filled on 9- track, 6250 BPI, standard-labeled tapes with characters written in EBCDIC. Requests should be addressed to: Carbon Dioxide Information Analysis Center Oak Ridge National Laboratory Post Office Box 2008 Oak Ridge, Tennessee 37831-6335, U.S.A. Telephone:(423) 574-0390 Fax: (423) 574-2232 Electronic Mail: cdiac@ornl.gov FTP: cdiac.esd.ornl.gov (128.219.24.36) Enter "anonymous" as the userid. Enter your electronic mail address as the password (e.g., "d9k@ornl.gov"). Change to the directory "pub/tr055". 5. References Bradley, R. S., P. M. Kelly, P. D. Jones, C. M. Goodess, and H. F. Diaz. 1985. A climatic data bank for northern hemisphere land areas, 1851-1980. DOE/EV/10739-2. Carbon Dioxide Research Division, U.S. Department of Energy, Washington, D.C. Eischeid, J. K., H. F. Diaz, R. S. Bradley, and P. D. Jones. 1991. A comprehensive precipitation data set for global land areas. DOE/ER-69017T-H1. Carbon Dioxide Research Division, U.S. Department of Energy, Washington, D.C. Jones, P. D., S. C. B. Raper, B. Santer, B. S. G. Cherry, C. Goodess, P. M. Kelly, T. M. L. Wigley, R. S. Bradley, and H. F. Diaz. 1985. A grid point surface air temperature data set for the northern hemisphere. DOE/EV/10098-2. Carbon Dioxide Research Division, U.S. Department of Energy, Washington, D.C. Jones, P. D., P. Ya. Groisman, M. Coughlan, N. Plummer, W.-C. Wang, and T. R. Karl. 1990. Assessment of urbanization effects in time series of surface air temperature over land. Nature 347:169-72. Koomanoff, F. A., Ye Duzheng, Zhao Jianping, M. R. Riches, W.-C. Wang, and Tao Shiyan. 1988. The United States' Department of Energy and the People's Republic of China's Chinese Academy of Sciences joint research on the greenhouse effect. Bull. Amer. Meteor. Soc. 69:1301-8. Marland, G. 1991. Global and National CO2 Emissions from Fossil Fuel Burning, Cement Production, and Gas Flaring Modern Record, Global. pp. 92-93. In Boden, T. A., P. Kanciruk, and M. P. Farrell (eds.), Trends '90: A Compendium of Data on Global Change, ORNL/CDIAC-36. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee, U.S.A. Marland, G., and T. A. Boden. 1992. CO2 Emissions Modern Record, Global. pp.386-389. In Boden, T. A., R. J. Sepanski, and F. W. Stoss (eds.), Trends '91: A Compendium of Data on Global Change, ORNL/CDIAC- 46. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, Oak Ridge,Tennessee, U.S.A. Marland, G., and R. M. Rotty. 1984. Carbon dioxide emissions from fossil fuels: A procedure for estimation and results for 1950-1982. Tellus 36(B):232-61. National Environmental Satellite, Data, and Information Service. 1981-1983. World Weather Records, 1961-1970 (Vols. 1-6). U.S. Department of Commerce, Washington, D.C. Riches, M. R., Zhao Jianping, W.-C. Wang and Tao Shiyan, 1992: The U.S. Department of Energy and the People's Republic of China's Academy of Sciences joint research on the greenhouse effect: 1985-1991 research progress. Bull. Amer. Meteor. Soc., 69, 1301-1308. Smithsonian Institution. 1927. World Weather Records, 1920. Miscellaneous Collections, Volume 79. Washington, D.C. Smithsonian Institution. 1934. World Weather Records, 1921-1930. Miscellaneous Collections, Volume 90. Washington, D.C. Smithsonian Institution. 1947. World Weather Records, 1931-1940. Miscellaneous Collections, Volume 105. Washington, D.C. Spangler, W. M. L., and R. L. Jenne. 1990. World monthly surface station climatology (and associated datasets). National Center for Atmospheric Research, Boulder, Colorado. Steurer, P. M., and T. R. Karl. 1991. Historical sunshine and cloud data in the United States. ORNL/CDIAC-43, NDP-021/R1. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, Oak Ridge, Tenn. Tao, Shiyan, Congbin Fu, Zhaomei Zeng, and Qingyun Zhang. 1991. Two long-term instrumental climatic data bases of the People's Republic of China. ORNL/CDIAC-47, NDP-039. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee. U.S. Weather Bureau. 1959. World Weather Records, 1941-50 (Vols. 1-6). U.S. Department of Commerce, Washington, D.C. U.S. Weather Bureau. 1967. World Weather Records, 1951-60 (Vols. 1-6). U.S. Department of Commerce, Washington, D.C. Vose, R. S., R. L. Schmoyer, P. M. Steurer, T. C. Peterson, R. Heim, T. R. Karl, and J. K. Eischeid. 1992. The Global Historical Climatology Network: long-term monthly temperature, precipitation, sea level pressure, and station pressure data. ORNL/CDIAC-53, NDP-041. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee. Wang, W.-C., Z. M. Zeng, and T. R. Karl. 1990. Urban heat islands in China. Geophy. Res. Lett. 17(12):2377-80. Appendix A Instrumentation and Data Collection Methods Barometric Pressure Fortin and Kew-pattern barometers and an aneroid barograph are employed. They are positioned in observation rooms to decrease temperature variability. The two instruments are positioned near each other, away from doors and windows, and are calibrated at regular intervals. Station pressures are recorded in millibars, with monthly means being calculated from daily means and reported to the nearest tenth of a millibar. Mercury column heights, expressed in millimeters, had been reported before 1953 for some stations, but they have been converted to millibars. Since 1950, readings have been corrected and reduced for temperature effects, instrumental error, and gravity error (including latitude and altitude effects). Readings were not corrected for gravity effects prior to 1950. Temperature Dry- and wet-bulb thermometers are positioned together in an instrument shelter. The standard bulb heights used prior to 1950 are not known. For the period 1954-1960,the standard height was 2m. The standard height used since 1961 is 1.5m, as it was for the period 1950-1953. Observing times have varied over the years. The observing times for each station prior to 1950, along with details on which observations were used in calculating the daily mean, may be found in the accompanying station histories (Appendix B, Tao et al. (1991)). Since 1950, observations have been made using Local Standard Time (LST) (1951-1953), Local Mean Solar Time (LMST) (1954-July 1960), and Beijing Time (BT) (August 1960-present). Maximum and minimum thermometers are laid horizontally in the same shelter, 3 and 2 cm higher, respectively, than the dry- and wet-bulb thermometers. Prior to 1951, observation and adjustment were performed at 2000 BT but since 1951 have taken place at 2000 LST. Relative Humidity A ventilated psychrometer and hair hygrometer (models not given) are housed in separate shelters. Readings from each instrument are translated into relative humidities via their respective tables or charts. Temperature observations are made simultaneously. Circa 1953, certain stations (not identified) used a different humidity table that resulted in errors of 1-2%. Precipitation A Dines tilting-siphon rain gauge and a siphon rainfall recorder are used. Observation times prior to 1950 are not known. Since then, observations have been taken at midnight LST (1951-1953), 1900 LMST (1954-July 1960), and 2000 BT (August 1960-present). Observed totals may include liquid precipitation, liquid equivalent of solid precipitation, or frost, dew, or fog. Amounts less than 0.05mm are recorded as zero. Sunshine Duration Prior to 1954, a Jordan Photographic Sunshine Recorder was used, and since 1954 a Campbell-Stokes Sunshine Recorder has been used. CAS states that some monthly sunshine durations have been estimated, but these entries have not been flagged or documented. Cloud Amount Cloud amount has been estimated in tenths of sky cover by observers. Zero indicates clear skies; 10 indicates overcast skies. Monthly mean cloud amounts are obtained from averaging mean daily amounts for the month, multiplying by 10 to obtain a percentage, and rounding this value to the nearest whole percent. CAS states that the data contain many estimates, but, as with the sunshine data, these have not been identified by flagging or documentation. Wind Data Since 1954, an EL electric wind direction and speed device and a Dines wind direction and speed recorder have been used. Receivers for wind instruments are mounted on a pole 10-12m above ground level. The type of instrument used before 1954 is unclear, but at the following stations the Beaufort Scale was employed: ZhangYe (52652) LanZhou (52889) YanTai (54765) LaSa (55591) TengChong (56739) TianShui (57006) ZhengZhou (57083) YiChang (57461) ChangSha (57679) GuiYang (57816) AnQing (58424) WenZhou (58659) FuZhou (58847) XiaMen (59134) WuZhou (59265) ShanTou (59316) HaiKou (59758) The Beaufort Scale entries from these stations have been converted to m/s. Observation times used in calculating the daily mean are unclear for the period prior to 1951. Several different time groups were used over the period 1951-1953 (Appendix B). For the period 1954-July 1960, observations from 0100, 0700, 1300, and 1900 were used (presumably LMST), and since August 1960, observations from 0200, 0800, 1400, and 2000 have been used (presumably BT). Wind direction is recorded in 22.5 degree increments of azimuth clockwise from north (sixteen directions), with 0 indicating calm winds and 360 indicating a north wind. The monthly dominant wind direction is simply the most frequent wind direction observed during the month, and its frequency (percentage of the time it was observed) is the dominant wind frequency.