DATASET TITLE: MONTHLY MEAN PRESSURE RECONSTRUCTIONS FOR EUROPE (1780-1980) AND NORTH AMERICA (1858-1980) AUTHORS: P.D. JONES T.M.L. WIGLEY K.R. BRIFFA CLIMATIC RESEARCH UNIT SCHOOL OF ENVIRONMENTAL SCIENCES UNIVERSITY OF EAST ANGLIA NORWICH, UNITED KINGDOM SCOPE OF THE DATA: THE DATA REPRESENT MONTHLY MEAN GRID-POINT PRESSURE RECONSTRUCTIONS FOR EUROPE FOROM 1780-1980 AND FOR NORTH AMERICA FROM 1858-1980. THE DATA ARE DERIVED FROM BOTH DIRECT AND RECONSTRUCTED SOURCES OF MONTHLY MEAN PRESSURE DATA. THE RECONSTRUCTIONS ARE BASED ON A PRINCIPLE COMPONENTS REGRESSION TECHNIQUE WHICH RELATES SURFACE PRESSURE PATTERNS TO THOSE OF STATION TEMPERATURE, PRECIPITATION, AND PRESSURE DATA. RECONSTRUCTED VALUES ARE GIVEN UP TO A TIME WHEN REAL GRID POINT DATA BECAME AVAILABLE; TO 1872 FOR EUROPE AND TO 1898 FOR NORTH AMERICA, RESPECTIVELY. ADDITIONALLY, THE FEW MISSING VALUES IN THE UKMO DATA SET (POST 1873) AND NORTH AMERICA (POST 1899) WERE REPLACED WITH THE BEST RECONSTRUCTED VALUE. THE EUROPEAN DATA HAVE SIXTY GRID POINTS SPANNING 35-70 DEGREES N AND 30 DEGREES W-40 DEGREES E ON A 5 DEGREE LATITUDE BY 10 DEGREE LONGITUDE (20 DEGREES AT 70 DEGREES N) GRID. THE NORTH AMERICAN DATA FILE HAS FORTY-EIGHT GRID POINTS ON A 5 DEGREE LATITUDE BY 10 DEGREE LONGITUDE GRID AND COVERS 30-55 DEGREES N AND 60-130 DEGREES W. DATA FORMAT: FIVE DOS ASCII TEXT FILES ARE PROVIDED IN THIS SUBDIRECTORY (NDP025) INCLUDING THIS DOCUMENTATION FILE (NDP025.TXT), TWO DATA FILES CONTAINING MONTHLY MEAN PRESSURE RECONSTRUCTIONS FOR EUROPE AND NORTH AMERICA (NDP025.EUR & NDP025.NAM), AND TWO FORTRAN RETRIEVAL CODES TO READ AND PRINT THE DATA FILES (NDP025.FR1 & NDP025.FR2). THE RECONSTRUCTIONS ARE EXPRESSED TO THE NEAREST TENTH OF A MILLIBAR, HAVE ALL BEEN ADJUSTED TO MEAN SEA-LEVEL, AND NEITHER THE EUROPEAN NOR THE NORTH AMERICAN DATA FILES CONTAIN ANY MISSING VALUES. THE EUROPEAN DATA FILE CONTAINS 12,120 LINES AND THE NORTH AMERICA DATA FILE CONTAINS 5904 LINES. FOUR VARIABLES ARE DEFINED FOR EACH DATA FILE: YEAR (IYEAR), MONTHLY MEAN PRESSURE RECONSTRUCTIONS (MONTH), QUALITY CODE (CODE), AND ANNUAL MEAN PRESSURE (ANNUAL). FOLLOWING EACH PRESSURE VALUE A QUALITY CODE IS GIVEN ACCORDING TO THE FOLLOWING CRITERIA: QUALITY CODE MODEL PERFORMANCE OVER THE VERIFICATION PERIOD 1 MORE THAN 50% VARIANCE EXPLAINED 2 CORRELATION SIGNIFICANT AT THE 0.01 LEVEL 3 CORRELATION SIGNIFICANT AT THE 0.05 LEVEL 4 CORRELATION NOT SIGNIFICANT AT THE 0.05 LEVEL NO CODE REAL UKMO DATA SET VALUE A HEADER RECORD TO IDENTIFY GRID POINTS PRECEDES EACH BLOCK OF DATA.THE HEADER RECORD AND DATA FOR THE EUROPEAN FILE MAY BE READ BY THE FOLLOWING FORMAT: READ(5,10,END=99) (HEADER(J),J=1,20) 10 FORMAT(20A4) WRITE(6,11) (HEADER(J),J=1,20) 11 FORMAT(20A4) DO 14 I=1,201 READ(5,12) IYEAR(I),(MONTH(K),CODE(K),K=1,12),ANNUAL(I) 12 FORMAT(1X,I4,1X,12(F6.1,A2,1X),F6.1) THE NORTH AMERICAN HEADER RECORD AND DATA MAY BE READ BY THE FOLLOWING FORMAT: READ(5,12,END=99) (HEADER(J),J=1,20) 10 FORMAT(20A4) WRITE(6,11)(HEADER(J),J=1,20) 11 FORMAT(20A4) DO 14 I=1,123 READ(5,12) IYEAR(I),(MONTH(K),CODE(K),K=1,12),ANNUAL(I) 12 FORMAT(1X,I4,1X,12(F6.1,A2,1X),F6.1) REFERENCES BRIFFA, K.R., P.D. JONES, T.M.L. WIGLEY, J.R. PILCHER, AND M.G.L. BAILLIE. 1986. CLIMATE RECONSTRUCTIONS FROM TREE RINGS: PART 2, SPATIAL RECONSTRUCTION OF SUMMER MEAN-SEA-LEVEL PRESSURE PATTERNS OVER GREAT BRITAIN. JOURNAL OF CLIMATOLOGY 6:1-15. JENNE, R. 1975. DATA SETS FOR METEOROLOGICAL RESEARCH. NCAR TECHNICAL REPORT 1A-111, NATIONAL CENTER FOR ATMOSPHERIC RESEARCH, BOULDER, COLORADO. JONES, P.D., T.M.L. WIGLEY, AND K.R. BRIFFA. 1983. RECONSTRUCTING SURFACE PRESSURE PATTERNS USING PRINCIPAL COMPONENTS REGRESSION ON TEMPERATURE AND PRECIPITATION DATA. PROC. INT. MEETING ON STATISTICAL CLIMATOLOGY, INSTITUTO NACIONAL DE METEOROLOGIA GEOFISICA, LISBON, 4.2.1-4.2.8. JONES, P.D., T.M.L. WIGLEY, AND K.R. BRIFFA. 1987. MONTHLY MEAN PRESSURE RECONSTRUCTIONS FOR EUROPE (1780-1980) AND NORTH AMERICA (1858-1980). DOE TECHNICAL REPORT NO. TR037. U.S. DEPARTMENT OF ENERGY, CARBON DIOXIDE RESEARCH DIVISION, WASHINGTON, D.C. KINGTON, J.A. 1980. DAILY WEATHER MAPPING FROM 1781. CLIMATIC CHANGE 3:7-36. LAMB, H.H., AND A.I. JOHNSON. 1966. SECULAR VARIATIONS OF THE ATMOSPHERIC CIRCULATION SINCE 1750. GEOPHYS. MEM., 110, LONDON (H.M.S.O. FOR MET. OFFICE). TRENBERTH, K.A. AND D.A. PAOLINO. 1980. THE NORTHERN HEMISPHERE SEA-LEVEL PRESSURE DATA SET: TRENDS, ERRORS, AND DISCONTINUITIES. MONTHLY WEATHER REVIEW 108:855-872. WILLIAMS, J. AND H. VAN LOON. 1976. AN EXAMINATION OF THE NORTHERN HEMISPHERE SEA-LEVEL PRESSURE DATA SET. MONTHLY WEATHER REVIEW 104:1354-1361.