START****-*README**-*********-*********-*********-*********-*********-*********- This file contains 452 80-character lines. . This file is a brief documentation of the data archive: . . CLIMATOLOGICAL DATA FOR CLOUDS OVER THE GLOBE . FROM SURFACE OBSERVATIONS, 1982-1991: . The Total Cloud Edition (Documentation) . . October, 1994 . . Carole J. Hahn . Cooperative Institute for . Research in Environmental Sciences . University of Colorado . Boulder, CO 80309 . . Stephen G. Warren . Department of Atmospheric Sciences . University of Washington . Seattle, WA 98195 . . Julius London . Department of Astrophysical, Planetary and . Atmospheric Sciences . University of Colorado . Boulder, CO 80309 . _ . It is recommended that the user obtain the full documentation available from: . . Carbon Dioxide Information Analysis Center . Oak Ridge National Laboratory . Post Office Box 2008 . Oak Ridge, TN 37831-6050, U.S.A. . Telephone (615) 574-0390 . . or . . Data Support Section . National Center for Atmospheric Research . Boulder, CO 80307, U.S.A. . Telephone (303) 497-1215 . _ . This documentation consists of Tables 3-8 from the full documentation: . Table 3. Grid Box Sizes . Table 4. File Information . Table 5. Data Organization . Table 6. List of Formats for Reading Data Records . Table 7. Map Group Header Record Format and Codes . Table 8. Description of Terms and Abbreviations Used . . COMMENTS: . General . The Total Cloud Edition contains various annual, seasonal and monthly . averages for total cloud cover and the frequencies of occurrence of clear sky,. precipitation, and sky-obscured due to fog (these latter three are collectively referred to here as "weather types"). Data are provided in grid boxes that are typically 2.5x2.5 deg (lat x lon) for land and 5x5 deg for ocean. . Source data for these analyses were surface synoptic weather reports . obtained from the National Meteorological Center archives and from the . Comprehensive Ocean-Atmosphere Data Set. Synoptic reports are recorded 8 . times per day: 00, 03, 06, 09, 12, 15, 18, 21 GMT. . . Illuminance criterion . To minimize the night-detection bias inherent in surface observations, the . "illuminance criterion" of Hahn et al. (Hahn,C.J., S.G.Warren and J.London, . 1994, J. Climate, submitted) has been applied in most analyses of total . cloud cover and clear-sky frequency. Nighttime observations were discarded if. the illuminance of the moon (or sun) did not exceed the specified threshold . illuminance. Since the detection of precipitation or fog is insensitive to . illumination, these analyses were performed using all observations. For . comparative purposes, some analyses of total cloud and clear sky were also . performed utilizing all observations. These are indicated by the word "all" . in Table 5. . . Averaging method . An average for a single synoptic hour, or for daytime or nighttime only, was. obtained simply by averaging all the contributing reports. Because many . nighttime reports are discarded due to the illuminance criterion, there are . far fewer contributing reports at night than during the daytime. Therefore, . to obtain the "daily" average, daytime and nighttime averages are first . determined separately and then averaged together. . . Data organization . Each file contains a series of "map groups". A map group consists of the . data records for a number of grid boxes over the globe and a header record . which identifies the group: . . | Header record identifying map group . | Data record for first box . | Data record for second box . | etc. for number of boxes specified in header . . The order of the map groups on the tape is indicated in Table 5. Data record . formats are shown in Table 6 and the header record is described in Table 7. . The number of data records within a map group depends on the grid size and . whether it is for land or ocean. Since land-only grid boxes would have no data in an ocean map group (and visa versa), data records for such boxes are simply. not written. Box numbers based on the full grid are provided in the data . record itself. The numbers of boxes given within each type of map group are . listed in a footnote to Table 5 and are coded in the header record. . All data were written as integers but if read with the specified formats, . the proper floating point values will be obtained. (Cloud cover and frequencies are given as percent.) . Any data variable for which no value is reported is assigned the "missing . value code", which was chosen to be -9. The trend (file 16, formats 51 & 52) . is the only data variable for which a negative value is valid. Thus for . trends the missing value code should be considered to be NYRS=0. . _ . Tables follow. . *********-*********-*********-*********-*********-*********-*********-*********- Table 3. Grid Box Sizes . ___________________________________________________________ . Box size Dimensions Number of boxes in . (shorthand) lat x lon Latitude range . degrees zone globe . ___________ __________ ______________ __________________ . . 2.5x2.5c 7290 . (2c) 2.5x2.5 50N to 50S 144 . 2.5x5 50 to 70 72 . 2.5x10 70 to 80 36 . 2.5x20 80 to 85 18 . 2.5x40 85 to 87.5 8 . 2.5x360 87.5 to 90 1 . . 5x5c 1820 . (5c) 5x5 50N to 50S 72 . 5x10 50 to 70 36 . 5x20 70 to 80 18 . 5x40 80 to 85 9 . 5x360 85 to 90 1 . . 10x20c 230 . (10c) 10x20 50N to 50S 18 . 10x40 50 to 70 9 . 10x60 70 to 80 6 . 10x360 80 to 90 1 . ___________________________________________________________ . *********-*********-*********-*********-*********-*********-*********-*********- Table 4. File Information (Total Cloud Edition) . _______________________________________________________________________________. File Group General Logical Characters Characters. cluster contents records per record . name . ____ _______ _____________________________ __________ ___________ __________. . 1 RDME README (brief documentation) 452 80 36,160. . 2 LLFR Latitude,Longitude, 9,343 24 224,232. Land-fraction & . Number of land stations . for grid boxes . . 3 TWLO Land & Ocean Combined 123,828 " 2,971,872. total cloud & weather types . . 4 TCCL Land Total Cloud Cover 472,038 " 11,328,912. . 5 TCCL Land Total Cloud Cover 2,217,600 " 53,222,400. by synoptic hour, monthly . . 6 TCCO Ocean Total Cloud Cover 229,134 " 5,499,216. . 7 TCCO Ocean Total Cloud Cover 1,434,240 " 34,421,760. by synoptic hour, monthly . . 8 WXTL Land Weather Types 720,346 " 17,288,304. . 9 WXTL Land Clear-sky Frequency 2,217,600 " 53,222,400. by synoptic hour, monthly . . 10 WXTL Land Precipitation Frequency 2,217,600 " 53,222,400. by synoptic hour, monthly . . 11 WXTL Land Fog(sky-obscured) Freq. 2,217,600 " 53,222,400. by synoptic hour, monthly . . 12 WXTO Ocean Weather Types 156,954 " 3,766,896. . 13 WXTO Ocean Clear-sky Frequency 1,434,240 " 34,421,760. by synoptic hour, monthly . . 14 WXTO Ocean Precipitation Freq. 1,434,240 " 34,421,760. by synoptic hour, monthly . . 15 WXTO Ocean Fog(sky-obscured) Freq. 1,434,240 " 34,421,760. by synoptic hour, monthly . . 16 HIAV Harmonics & Interannual 96,528 " 2,316,672. Variation, land and ocean, . total cloud & weather types . _______________________________________________________________________________. *********-*********-*********-*********-*********-*********-*********-*********- Table 5. Data Organization . Contents of Surface-based Cloud Climatology Archive, 1982-1991# . Total Cloud Edition## . ________________________________________________________________________________ Number Map Data . File of map group Contents (coded in group header, Table 7) format. groups numbers (Table 6) _____ ______ _________ _______________________________________________ ________ 1 README text . 2-16 9003 . . 2 3 1-3 GRID LAT,LON,LAND FRACTION, NUM. LAND STATIONS . 1 1 1820 5x5c boxes 10 . 1 2 230 10x20c boxes 10 . 1 3 7290 2.5x2.5c boxes 10 . . grid* groups** . ____ ____________________ . 3 68 1-68 LAND+OCEAN . 1 1 Mean Annual TC 5c 1ann 22 . 3 2-4 Mean Annual WT " 1ann,3types 32 . 4 5-8 Mean Seasonal TC " 4sns 22 . 12 9-20 Mean Seasonal WT " 4sns,3types 32 . 12 21-32 Mean Monthly TC " 12mns 22 . 36 33-68 Mean Monthly WT " 12mns,3types 32 . ____ ____________________ . 4 1217 1-1217 LAND TOTAL CLOUD . 1 1 Mean Annual 2c 1ann 22 . 4 2-5 Mean Seasonal " 4sns 22 . 4 6-9 daytime " 4sns 22 . 32 10-41 by synoptic hour " 8hrs,4sns 22 . 12 42-53 Mean Monthly " 12mns 22 . 4 54-57 Mean Seasonal (all) 5c 4sns 22 . 40 58-97 Seasonal Means(all) " 4sns,10yrs 22 . 40 98-137 Seasonal Means " 4sns,10yrs 22 . 40 138-177 Seasonal Means 2c 4sns,10yrs 22 . 40 178-217 daytime " 4sns,10yrs 22 . 40 218-257 nighttime " 4sns,10yrs 22 . Monthly means . 5 960 258-1217 by synoptic hour 2c 8hrs,12mns,10yrs 22 . ____ ____________________ . 6 1181 1-1181 OCEAN TOTAL CLOUD . 1 1 Mean Annual 5c 1ann 22 . 4 2-5 Mean Seasonal " 4sns 22 . 4 6-9 daytime " 4sns 22 . 4 10-13 Mean Seasonal 10c 4sns 22 . 32 14-45 by synoptic hour " 8hrs,4sns 22 . 12 46-57 Mean Monthly 5c 12mns 22 . 4 58-61 Mean Seasonal (all) 10c 4sns 22 . 40 62-101 Seasonal Means(all) " 4sns,10yrs 22 . 40 102-141 Seasonal Means 5c 4sns,10yrs 22 . 40 142-181 daytime " 4sns,10yrs 22 . 40 182-221 nighttime " 4sns,10yrs 22 . Monthly means . 7 960 222-1181 by synoptic hour 5c 8hrs,12mns,10yrs 22 . ____ ____________________ . 8 3247 1-3247 LAND WEATHER TYPES . 3 1-3 Mean Annual 2c 1ann,3types 32 . 12 4-15 Mean Seasonal " 4sns,3types 32 . 12 16-27 daytime " 4sns,3types 32 . 96 28-123 by synoptic hour " 8hrs,4sns,3types 32 . 36 124-159 Mean Monthly " 12mns,3types 32 . 8 160-167 Mean Seasonal (all) 5c 4sns,2types 32 . 80 168-247 Seasonal Means(all) " 4sns,10yrs,2types 32 . 120 248-367 Seasonal Means 2c 4sns,10yrs,3types 32 . Monthly means . 9-11 2880 368-3247 by synoptic hour " 8hr,12mn,10yr,3types 32 . ____ ____________________ . 12 3215 1-3215 OCEAN WEATHER TYPES . 3 1-3 Mean Annual 5c 1ann,3types 32 . 12 4-15 Mean Seasonal " 4sns,3types 32 . 12 16-27 daytime " 4sns,3types 32 . 12 28-39 Mean Seasonal 10c 4sns,3types 32 . 96 40-135 by synoptic hour " 8hrs,4sns,3types 32 . 36 136-171 Mean Monthly 5c 12mns,3types 32 . 4 172-175 Mean Seasonal (all) 10c 4sns,1type 32 . 40 176-215 Seasonal Means(all) " 4sns,10yrs,1type 32 . 120 216-335 Seasonal Means " 4sns,10yrs,3types 32 . Monthly means . 13-15 2880 336-3215 by synoptic hour 5c 8hr,12mn,10yr,3types 32 . ____ ____________________ . 16 72 1-72 HARMONICS & IAV . 1 1 Annual TC, land 2c 1ann 40 . 3 2-4 Annual WT, land " 1ann,3types 40 . 4 5-8 Diurnal TC, land " 4sns 41 . 12 9-20 Diurnal WT, land " 4sns,3types 42 . 1 21 Annual TC, ocean 5c 1ann 40 . 3 22-24 Annual WT, ocean 5c 1ann,3types 40 . 4 25-28 Diurnal TC, ocean 10c 4sns 41 . 12 29-40 Diurnal WT, ocean " 4sns,3types 42 . 4 41-44 IAV TC, land 2c 4sns 51 . 12 45-56 IAV WT, land " 4sns,3types 52 . 4 57-60 IAV TC, ocean 10c 4sns 51 . 12 61-72 IAV WT, ocean " 4sns,3types 52 . ________________________________________________________________________________ # Non-standard terms are defined in Table 8. Briefly: . TC= total cloud; WT= "weather types" (clear sky, precipitation, fog). . ## Illuminance criterion applied to total cloud and clear sky unless "all" . specified. Ppt and fog always determined from all observations. . * Grid sizes are described in Table 3. . Number of boxes archived for 2c land = 2309, for 5c land = 861, . for 5c ocean = 1493, for 5c land+ocean = 1820, and for 10c ocean = 230 . ** Months are given in the order: Dec, Jan, Feb,...Nov. . If "2types" are specified, they are clear sky and fog. . If "1type" is specified, it is clear sky. . Convention for the order of groups in a multigroup listing is: . increment left group qualifier while holding right qualifier constant. . *********-*********-*********-*********-*********-*********-*********-*********- Table 6. List of Formats for Reading Data Records* . (Total Cloud Edition) . ___________________________________________________________ . Data . class . ______ . Format Variables and Format . number . ______ __________________________________________________ . . 1_____ Lat,Lon, Land-fraction, Number of land stations . . I4 F5.2 F5.2 F5.4 I5 . 10 BOX CLAT CLON FRL NLSTA . ___________________________________________________________ . . 2_____ Total Cloud . . 22 I4 I6 F5.2 F4.1 I2 I1 I2 . BOX NOBS AMT SD IDN LOB NSN . ___________________________________________________________ . . 3_____ Weather Types . . 32 I4 I6 F5.2 F4.1 I2 I1 I2 . BOX NOBS FQ SD IDN LOB NSN . ___________________________________________________________ . . 4_____ Harmonic analyses . . I4 F5.2 F5.2 F4.1 I2 F4.1 . BOX PHASE AMP VAF NT AVG . 40 (for annual harmonic) . 41 (for diurnal AMT) . 42 (for diurnal FQ) . ___________________________________________________________ . . 5_____ Interannual variations and trends . . I4 I2 I2 F5.2 F6.3 F5.3 . BOX NYRS SPAN IAV TRND UNC . 51 (for AMT) . 52 (for FQ) . ___________________________________________________________ . * Terms defined in Table 8. . Data records are 24 characters. . *********-*********-*********-*********-*********-*********-*********-*********- Table 7. Map Group Header Record Format and Codes* . (Total Cloud Edition) . ________________________________________________________________________________ Format I4 I4 I2 I1 I1 I4 I2 I2 I2 I2 . Parameters MGRP NBXS SIZE LO IMOON YEAR SN TIME TYPE FMT . Values 1 230 10 1=Land 0=Moon 1981 0=ann -3night 1=TCC 10 | 1820 5 2=Ocean 1=All | 41=DJF -2day 2=CLR 22 3247 7290 2 3=Global 1991 42=MAM -1daily 3=PPT 32 861 8190 43=JJA 00GMT 11=FOG 40 1493 8291 44=SON 03 41 2309 06 42 1=Jan 09 51 | 12 52 12=Dec 15 . 18 . 21 . ________________________________________________________________________________ * Terms are defined in Tables 3 & 8. Here "Moon" signifies that the . illuminance criterion has been applied, and "All" that it has not. . YEAR,SN,TIME, and TYPE are set to -9 in file 2. . . *********-*********-*********-*********-*********-*********-*********-*********- Table 8. Terms and Abbreviations Used . ______________________________________________________________________________. Term Meaning and description . . AMP Absolute amplitude of harmonic (not normalized). . AMT Average amount of cloud cover, given in percent. . ann Annual. . AVG Average AMT or FQ. In formats 40-42 it is the average of . NT values. . BOX Box number specific to grid size. See Table 3. . CLAT Center latitude of grid box. Values +90 to -90 for N to S. CLON Center longitude of grid box. Values 0 to 360 East. . day(time) Local time 06-18. . clr Clear sky. . DJF December (of the previous year), January, February. . FMT Data format number (see Table 6) . fog Sky-obscured due to fog (N=9, ww=10-12 or 40-49). . FQ Frequency of occurrence; given in percent. . FRL Fraction of area in grid box that is land. Values 0 to 1.. GMT Greenwich Mean Time. . IAV Interannual variation (standard deviation of contributing. year averages). . IDN Indicator that reports contributing to box average were . from day only (=1), night only (=2), both (=3) or had . less than specified minimum observations (=4) {see text} IMOON Indicates whether the illuminance criterion has been . applied (=0) or not (=1). . JJA June, July, August. . hrs Hours. . lat Latitude. . LO Indicator that group data are intended to be for . land (=1), ocean (=2), or both (=3). . LOB Indicator that box data were from land only (=1), ocean . only (=2), or both (=3). . lon Longitude. . MAM March, April, May. . MGRP Map group number. Increments serially through group . cluster (see Tables 4 & 5). . missing value code The integer -9. Inserted in data record where no . legitimate value is reported. (In formats 51-52 use . NYRS=0 for missing value code.) . N Symbol representing total cloud cover in synoptic code. . night(time) Local time 18-06. . NLSTA Approximate average number of land stations reporting . in a 2c grid box. . NOBS Number of observations. . NSN Number of seasons contributing to annual average. . NT Number of synoptic hours used (4 or 8) for diurnal . harmonic analysis or number of months used (12) for . annual harmonic analysis. . NYRS Number of years contributing to trends and IAV. . mean seasonal Long-term average; average over several years for season.. mns Months. . PHASE Phase of first harmonic. Diurnal: 0-24 hours mean solar . time of box center (-9 if AMP=0). Annual: month (0.5 -. 12.4 [1.0 = middle of January, etc.]; 0 if AMP=0). . ppt Precipitation (ww= 50-99 excluding 76,78). . SD Standard deviation; in units of variable (not normalized). seasonal mean Average for an individual year for a particular season. . SIZE Grid box size indicator. . SN Season or month indicator. . sns Seasons (DJF, MAM, JJA, SON). . SON September, October, November. . SPAN Span of years contributing to trend and IAV (includes . first and last years contributing). . tcc Total cloud cover. . TIME Time of day for which group data apply. . TRND Trend. Slope of least-squares fit (change in average/yr).. TYPE Cloud or weather type code. . UNC Uncertainty of trend line; same units as TRND. . VAF Percent variance accounted for by first harmonic. . ww Symbol representing present weather in synoptic code. . YEAR Year or years for which group data apply. Coded as 19yr . for single years where yr gives the last 2 digits of . the year, and as yfyl for multi-year averages where . yf=yr of the first year and yl=yr of the last year . of the period of record. . yrs Years. . ______________________________________________________________________________. END******-*README**-*********-*********-*********-*********-*********-*********-