ETACSNOW.DOC


                             1.  TITLE

1.1  Data Set Identification.

     Global Snow Depth 

     (Monthly ; USAF/ETAC)

1.2  Data Base Table Name.

     Not applicable.

1.3  CD-ROM File Name. 

      \DATA\SN_ICSST\SNOW\ETAC\ETACmm.sfx

     Note: capital letters indicate fixed values that appear on the CD-ROM 
     exactly as shown here, lower case indicates characters (values) that 
     change for each path and file.

     The format used for the filenames is: ETACmm.sfx, where  mm is the month 
     of the year (e.g., 12=December).  The filename extension (.sfx), 
     identifies the data set content for the file (see Section 8.2) and is 
     equal to .ESD for this data set.

1.4  Revision Date Of This Document.

     April 5, 1995.

                             2.  INVESTIGATOR(S)

2.1  Investigator(s) Name And Title.

     Dudley J. Foster, Jr. and Robert D. Davy
     USAF Environmental Technical Applications Center (USAF/ETAC).

2.2  Title Of Investigation.

     USAF Environmental Technical Applications Center Global Snow
     Depth Climatology.

2.3  Contacts (For Data Production Information).

_____________________________________________________________________________
|              |      Contact 1     |     Contact 2       |     Contact 3    |
|______________|____________________|_____________________|__________________|
|2.3.1 Name    |Mr.Dudley J. Foster |Mr. Robert D. Davy   |Dr. David Robinson|
|2.3.2 Address |USAF/ETAC           |USAF/ETAC            |Rutgers University|
|              |Technical Data Sect.|Technical Data Sect. |Geography Dept.   |
|      City/St.|Asheville, NC       |Asheville, NC        |New Brunswick, NJ |
|      Zip Code|28801-2723          |28801-2723           |08903             |
|2.3.3 Tel.    |(704) 259-0216      |(704) 259-0216       |(908) 932-4741    |
|2.3.4 Email   |None                |None                 |drobins@gandalf.  |
|              |                    |                     |rutgers.edu       |
|______________|____________________|_____________________|__________________|

2.4  Requested Form of Acknowledgment.

     Please cite the following publication when these data are used:

     Foster, D.J. and R.D. Davy, 1988. Global Snow Depth Climatology, 
     USAFETAC/TN-88/006, Scott Air Force Base, Illinois, 48 p.

                            3.  INTRODUCTION

3.1  Objective/Purpose.

     Create a global mid-monthly mean snow depth climatology with highest 
     resolution possible using all available station data for the months of
     September through June.

3.2  Summary of Parameters.

     Mean mid-monthly snow depths measured in inches.

3.3  Discussion.

     Following an extensive literature search, snow depth data were obtained 
     from as many sources as possible, worldwide.  A full bibliography of the 
     data sources is contained in the document USAF/ETAC/TN-88/006 Global Snow 
     Depth Climatology and in section 10.2.2, 12.1 and 12.2 of this document.  
     Each data source is rated according to a high, fair, or low confidence 
     level.  Data from the numerous sources were plotted on hemispheric maps 
     by month and the maps were manually analyzed.  Data were gridded to an 
     "eighth mesh" reference grid.  This grid divides the hemispheres into 64 
     equal boxes and each box is divided into 4,096 grid points that are 25 
     nautical miles (46 km) apart.  More information on the eighth grid can be 
     found in Hoke et al., 1979.  A mid-month-snow depth value to the nearest 
     whole inch was assigned to each box.  Each grid value was compared from 
     month to month to insure temporal consistency of the data.  The complete 
     grid was then digitized.  In certain data sparse areas such as 
     Antarctica, Greenland, China, and various mountain areas, special 
     methodologies were developed to provide mean snow depths.  These methods 
     are described in the Foster and Davy, 1988.  The data were regridded and 
     converted to metric units at the GSFC DAAC.

                        4.  THEORY OF MEASUREMENTS

The snow depth values represent measurement derived from a variety of methods.  
For more information on the measurements see the documents referenced in 
section 10.2.2, 12.1 and 12.2 below.  The data were analyzed by hand to an 8th 
mesh grid.  Note that these data relate to snowpack depth not Snow Water 
Equivalent (SWE).

                            5.  EQUIPMENT

5.1  Instrument Description.

     5.1.1  Platform.

            Ground.

     5.1.2  Mission Objectives.

            Create a global mid-monthly mean snow depth climatology with 
            highest resolution possible using all available station data for 
            the months of September through June.
 
     5.1.3  Key Variables.

            Snow depth.

     5.1.4  Principles of Operation.

            Manual measurement of the depth of snow accumulated on the ground 
            at a specific location.

     5.1.5  Instrument Measurement Geometry.

            Not applicable.

     5.1.6  Manufacturer of Instrument.

            Not applicable.

5.2  Calibration.

     5.2.1  Specifications.

            Not applicable.

            5.2.1.1  Tolerance.

                     Nearest 2.54 cm.

     5.2.2  Frequency of Calibration.

            Not applicable.

     5.2.3  Other Calibration Information.

            None.

                          6.  PROCEDURE

6.1  Data Acquisition Methods.

     Following an extensive literature search, snow depth data were obtained 
     from as many sources as possible, worldwide.  Data from the numerous 
     sources were plotted on hemispheric maps by month and the maps were 
     manually analyzed.  Data were gridded to an "eighth mesh" reference grid 
     (approx. 46 km).  A mid-month snow depth value to the nearest whole inch 
     was assigned to each box.  Each grid value was compared from month to 
     month to insure temporal consistency of the data.  The complete grid was 
     then digitized.

6.2  Spatial Characteristics.

     Spatial resolution of the input data (station measurements) is highly 
     variable.  Spatial resolution of the manually interpolated output data is 
     "eighth mesh" or approximately 46.3 km.  The Goddard DAAC converted the 
     data from the 46.3 km polar projection to an equal-angle grid described 
     below. See section 9.3.1 for the regridding procedure.

     6.2.1  Spatial Coverage.

            The coverage is global.  Data in each file are ordered from north 
            to south and from west to east beginning at 180 degrees west and 
            90 degrees north.  Point (1,1) represents the grid cell centered 
            at 89.5 N and 179.5 W (see section 8.4).

     6.2.2  Spatial Resolution.

            The data are given in an equal-angle lat/long grid that has a 
            spatial resolution of 1 X 1 degree lat/long.

6.3  Temporal Characteristics.

     6.3.1  Temporal Coverage.

            This is a climatolgy data set, therefore it is not year specific.

     6.3.2  Temporal Resolution.

            Climatology represents an average snow depth value for mid-month.

                                7.  OBSERVATIONS

7.1  Field Notes.

     Not applicable.

                              8.  DATA DESCRIPTION

8.1  Table Definition With Comments.

     Not applicable.

8.2  Type of Data.

--------------------------------------------------------------------------------
|                 8.2.1                  |               |          |          |
|Parameter/Variable Name                 | Snow depth    |          |          |
--------------------------------------------------------------------------------
|    |               8.2.2               |     8.2.3     |  8.2.4   |  8.2.5   |
|    |Parameter/Variable Description     |Range          |Units     |          |
--------------------------------------------------------------------------------
|SNOW_DEPTH                              |               |          |Various   |
|    |Average mid-month snow depth.      |min = 0        |[mm]      |climate   |
|    |                                   |max = 950      |          |data sets |
|    |                                   |fill = -9999   |          |          |
|    |                                   |               |          |          |
--------------------------------------------------------------------------------

8.3  Sample Data Base Data Record.

     Not applicable.

8.4  Data Format.

     The CD-ROM file format is ASCII, and consists of numerical fields of 
     varying length, which are space delimited and arranged in columns and 
     rows.  Each column contains 180 numerical values and each row contain 360 
     numerical values.  

          Grid arrangement

             ARRAY(I,J)
             I  = 1 IS CENTERED AT 179.5W
             I INCREASES EASTWARD BY 1 DEGREE
             J  = 1 IS CENTERED AT 89.5N
             J INCREASES SOUTHWARD BY 1 DEGREE

             90N - | - - - | - - - | - - - | - -
                   | (1,1) | (2,1) | (3,1) |
             89N - | - - - | - - - | - - - | - -
                   | (1,2) | (2,2) | (3,2) |
             88N - | - - - | - - - | - - - | - -
                   | (1,3) | (2,3) | (3,3) |
             87N - | - - - | - - - | - - - |
                  180W   179W    178W   177W

            ARRAY(360,180)

8.5  Related Data Sets.

     NOAA/NESDIS Northern Hemsiphere Snow Cover data on this CD-ROM.
     NMC/ECMWF Reanalysis Sea Ice data, on this CD-ROM.

                         9.  DATA MANIPULATIONS

9.1  Formulas.

     9.1.1  Derivation Techniques/Algorithms.

            None.

9.2  Data Processing Sequence.

     9.2.1  Processing Steps and Data Sets.

            See Section 3.3.

     9.2.2  Processing Changes.

            None.

9.3  Calculations.

     9.3.1  Special Corrections/Adjustments.

            The original data were in an 8th mesh grid.  An 8th mesh grid can 
            be visualized as a global hemisphere overlayed by an 8 x 8 grid, 
            for a total of 64 grid boxes.  Within each box, there are 64 x 64 
            points, totaling 4096 points of data values, approximately 46.3 km 
            apart.  The Goddard DAAC utilized a routine developed by USAF 
            Ice/Snow group to assign a latitude and longitude to each of the 
            4096 points within each of the 64 boxes.  These snow depth values 
            and their corresponding latitude and longitude were used to assign 
            each value to a 1 x 1 degree grid cell, maintaining a summation 
            and counter for any data values that fall within a grid cell.  
            Average snow depth values were then calculated for each grid cell.  
            The resulting 1 x 1 degree hemispheric grid of snow depth values 
            was then concatenated with the corresponding hemisphere of gridded 
            values for each month.  

            For latitudes higher than 65 deg. N and 65 deg. S, raw data 
            resolution exceeding the target resolution, resulting in empty 
            grids where data coverage should be continuous.  The Goddard DAAC 
            used the spline technique for unequally spaced intervals to 
            interpolate the missing snow depth values.  The software used to 
            perform this interpolation was provided by Dr. L. Bounoua 
            (NASA/GSFC, Code 923 (301 286-1406)).  


            The ISLSCP land/sea mask on this CD-ROM (LAND_SEA.MSK) was applied 
            to this data.

9.4  Graphs and Plots.

     Contour plots of mean mid-monthly snow depths for September through June 
     for the Northern Hemisphere in the original 8th mesh grid format are 
     provided in Foster & Davey, 1988.

                       10.  ERRORS

10.1  Sources of Error.

      Not available.

10.2  Quality Assessment.

      10.2.1  Data Validation by Source.

              Not available.

      10.2.2  Confidence Level/Accuracy Judgment.

              The confidence in sources for the USAF/ETAC Snow Depth data 
              varies by geographic location. Below is a comprehensive list of 
              regional sources. A confidence factor is included for each 
              region, which indicates the degree of confidence that can be 
              placed in the data produced for that region. The confidence 
              factors are explained as follows:

              High Confidence: Summarized snow depth values were available, 
              and there were more than 5 years period of record.

              Fair Confidence: Summarized snow depth values were limited; 
              discussion material was insufficient to produce a high degree of 
              confidence.

              Low Confidence: Summarized snow depth values were not available, 
              and there was only limited discussion material.

              AFRICA--High Confidence. Research suggested that snow cover was 
              not present long enough here (except on the mountain peaks) to 
              maintain a mean monthly snow depth or attempt inclusion in this 
              study.

              ALBANIA--High Confidence. Research suggested that snow cover was 
              not present long enough here (except on the higher mountain 
              peaks) to maintain a mean monthly snow depth or attempt 
              inclusion in this study.

              ANTARCTICA--Low Confidence. Snow depth was calculated in 
              Antarctica by dividing mean annual water equivalent by snow 
              density. Antarctic snow densities were acquired from a 
              literature search of sources. 

              Sources:

              Bull, C., 1971. "Snow Accumulation in Antarctica Research in 
                  Antarctica," Association Advancement Science, pp 367-421.
              Cameron, R.L., 1964. "Glaciological studies at Wilkes Station, 
                  Budd Coast, Antarctica," Antarctic Snow and Ice Studies--
                  American Geophysics Union, Antarctic Research Service, pp 
                  257-316.
              Camerson, R.L., 1964. "Glaciological studies at Byrd Station, 
                  Antarctica," 1963-65 Antarctic Snow and Ice Studies--
                  American Geophysics Union, Antarctic Research Service, pp 
                  127-156.
              Giovinetto, M.B., 1964. "The drainage systems of Antarctic: 
                  accumulation," Antarctic Snow and Ice Studies--American 
                  Geophysics Union, Antarctic Research Service, pp 127-156.
              Heap, J.A. and A.S. Rundle, 1964. "Snow Accumulation on the Ross 
                  Ice Shelf," Antarctica Antarctic Snow and Ice Studies--
                  American Geophysics Union, Antarctic Research Service, pp 
                  119-126.
              Koerner, R.M., 1964. "Firm stratigraphy studies on the Byrd-
                  Whitmore Mountains traverse," 1962-63 Antarctic Snow and Ice 
                  Studies--American Geophysics Union, Antarctic Research 
                  Service, pp 219-236.
              Koerner, R.M., 1971. "A stratigraphic method of determining the 
                  snow accumulation rate at Plateau Station, Antarctica, and 
                  application to South Pole-Queen Maud Land traverse 2, 1965-
                  66." Antarctic Snow and Ice Studies--American Geophysics 
                  Union, Antarctic Research Service, pp 225-238.
              Petit, J.R., J. Jouzel, M. Pourchet, and L. Merlivant, 1982. "A 
                  detailed study of snow accumulation and stable isotope 
                  content in Dome C (Antarctica)," Journal of Geophysics 
                  Research, pp 4301-4308.
              Rusin, N.P., 1961. Meteorological and Radiational Regime of 
                  Antarctica, Leningrad.
              Schwerdtfeger, W., 1970. "The Climate of the Antarctic,' World 
                  Survey of Climatology Volume 14, Climates of the Polar 
                  Regions, Elsevier Publishing Company, Amsterdam.
              Taylor, L.D., 1971. "Glaciological studies on the South Pole 
                  traverse," 1962-63 Antarctic Snow and Ice Studies, American 
                  Geophysics Union, Antarctic Research Service, pp 37-64.

              ARCTIC--Low Confidence.

              Sources:

              Petterssen, S., W.C. Jacobs, and B.C. Haynes, 1951. "The 
                  Meteorology of the Arctic Region, Part 1," Encyclopedia 
                  Arctica, Vol. VII.
              Petterssen, S., W.C. Jacobs, and B.C. Haynes, 1956. Meteorology 
                  of the Arctic, Chief of Naval Operations for Polar Projects, 
                  Washington, D.C.
              Schutz, C., L.D. Bregman, 1975. Global Snow Depth Data: A 
                  Monthly Summary, Rand Corporation, Santa Monica, CA.

              AUSTRALIA--Low Confidence.

              Sources:

              Bureau of Meteorology, 1979. The Climate of Hobart, Tasmania, 
                  Capital City Series, Australian Government Publishing 
                  Service, Canberra.
              Bureau of Meteorology, 1979. Climatic Survey, Sydney, Region 5 
                  New South Wales, Australia Government Publishing Service, 
                  Canberra.
              Lansberg, H.E. (ed.), 1976. World Survey of Climatology Vol 13, 
                  Climates of Australia and New Zealand, Elsevier Publishing 
                  Co., Amsterdam.
              U.S. Central Intelligence Agency, 1963. National Intelligence 
                  Survey, NIS 96, Australia, sect. 23, Weather and Climate, 
                  Washington D.C.

              AUSTRIA--Fair Confidence.

              Sources:

              Air Ministry Meteorological Office, 1944, Meteorological Report 
                  on the Alps, Supplement 1, London.

              BELGIUM--High Confidence. Research suggested that snow cover was 
              not present long enough to maintain a mean monthly snow depth.

              BULGARIA--Fair Confidence.

              Sources:

              U.S. Central Intelligence Agency, 1969. National Intelligence 
                  Survey, NIS 22-23, Romania and Bulgaria, sect. 23, Weather 
                  and Climate, Washington D.C.

              CANADA--High Confidence.

              Sources:

              Canadian Climatic Centre, unpublished analyzed snow depth charts 
                  1955-1980, Downsview, Ontario.
              Polter, J., 1965. Snow Cover, Climatological Studies, Number 3, 
                  Department of Transport Meteorological Branch, Toronto.

              CHINA--Fair Confidence. USAF/ETAC operating location A (OL-A) in 
              Asheville N.C. obtained five Chinese journal (1975-1979) from 
              the National Climatic Data Center (NCDC). These journals 
              contained maximum monthly snow depths for 200 Chinese stations. 
              After summarizing this data, a subjective value of 80 percent of 
              the total depth was used to estimate the mean.

              CZECHOSLOVAKIA--Fair Confidence.

              Sources:

              Koncek, M. and V. Briedon, 1964. Snow and Snow-Cover in 
                  Slovakia, Slovenska Akademia Vied, Bratislava.

              DENMARK--High Confidence. Research suggested that snow cover was 
              not present long enough to maintain a mean monthly snow depth.

              FINLAND--High Confidence.

              Sources:

              U.S. Central Intelligence Agency, 1965. National Intelligence 
                  Survey, NIS 12, Finland, sect. 23, Weather and Climate, 
                  Washington D.C.

              FRANCE--Fair Confidence.

              Sources:

              Garnier, M., 1967. Climatologie De La France, Memorial De La 
                  Meteorologie National, Paris.
              Navarre, Jean-Pierre, Etude Climatologique De L'enneigement Des 
                  Alpes A Ppartir Du Reseau Cedonigla, Donnees Et 
                  Statistiques, Saint-Martin D'Heres.

              GERMANY--High Confidence.

              Sources:

              "Summary of Day Data" (west German ABs), OL-A, USAFETAC, 
                  Asheville, NC.
              U.S. Central Intelligence Agency, 1963. National Intelligence 
                  Survey, NIS 13A, East Germany, sect. 23, Weather and 
                  Climate, Washington D.C.
              U.S. Central Intelligence Agency, 1957. National Intelligence 
                  Survey, NIS 13B, West Germany, sect. 23, Weather and 
                  Climate, Washington D.C.
              U.S. Army Corps of Engineers, 1954. Depth of Snow Cover in the 
                  Northern Hemisphere, Arctic Construction and Frost Effects 
                  Laboratory, New England Division, Boston.

              GREECE--High Confidence. Research suggested that snow cover was 
              not present long enough here (except on the higher mountain 
              peaks) to maintain a mean monthly snow depth or attempt 
              inclusion in the study.

              GREENLAND--Low Confidence.

              Sources:

              Bader, Henri, 1961. The Greenland Ice Sheet, U.S. Army Cold 
                  Regions Research and Engineering Laboratory, Hanover, NH.
              Mack, S.J., 1961. Accumulation Patterns on the Greenland Ice 
                  Sheet, U.S. Army Cold Regions Research and Engineering 
                  Laboratory, Hanover, NH.
              Petterssen, S., W.C. Jacobs, and B.C. Haynes, 1956. Meteorology 
                  of the Arctic, Chief of Naval Operations for Polar Projects, 
                  Washington, D.C.
              Schutz, C., and L.D. Bregman,1975.  Global Snow Depth Data: A 
                  Monthly Summary, The Rand Corporation, Santa Monica, CA.

              HUNGARY--High Confidence.

              Sources:

              Jozsef, Kakas, 1967. Magyarorszag Eghajlati Atlasza, Akademiai 
                  Kiado, Budapest.

              ICE-COVERED AREAS--High Confidence.

              Sources:

              Great Lakes Climatological Atlas, 1986. Minister of Supply and 
                  Services, Ottawa.
              Sea Ice Climatic Atlas--Vol 1 Antarctic, 1985. Naval 
                  Oceanography Command Detachment, Asheville, NC.
              Sea Ice Climatic Atlas--Vol 2 Arctic East, Vol 3-Arctic West, 
                  1985. Naval Oceanography Command Detachment, Asheville, NC.

              ICELAND--High Confidence.

              Sources:

              U.S. Central Intelligence Agency, 1963. National Intelligence 
                  Survey, NIS 68, Iceland, sect. 23, Weather and Climate, 
                  Washington D.C.

              IRAN--Low Confidence.

              U.S. Central Intelligence Agency,1970. National Intelligence 
                  Survey, NIS 33-34, Afghanistan and Iran, sect. 23, Weather 
                  and Climate, Washington D.C.

              ITALY--Low Confidence.

              Sources:

              U.S. Central Intelligence Agency, 1953. National Intelligence 
                  Survey, NIS 17, Italy, sect. 23, Weather and Climate, 
                  Washington D.C.

              IRELAND--High Confidence. Research suggested that snow cover was 
              not present long enough to maintain a mean monthly snow depth.

              JAPAN--Fair Confidence.

              Sources:

              "Summary of Day Data" (Japanese ABs) OL-A, USAFETAC, Asheville, 
                  NC.

              KOREA--Fair Confidence.

              Sources:

              "Summary of Day Data" (Korean ABs) OL-A, USAFETAC, Asheville, 
                  NC.
              U.S. Central Intelligence Agency, 1968. National Intelligence 
                  Survey, NIS 41, Korea, sect. 23, Weather and Climate, 
                  Washington D.C.
              Worldwide Airfield Climatic Data, 1967. Far East, USAFETAC, 
                  Washington D.C.

              LUXEMBOURG--High Confidence. Research suggested that snow cover 
              was not present long enough to maintain a mean monthly snow 
              depth.

              MIDDLE EAST--High Confidence. Research suggested that snow cover 
              was not present long enough to maintain a mean monthly snow 
              depth.

              MONGOLIA--Low Confidence.

              Sources:

              U.S. Central Intelligence Agency, 1966. National Intelligence 
                  Survey, NIS 40, Mongolia, sect. 23, Weather and Climate, 
                  Washington D.C.

              MOUNTAIN AREAS--Low Confidence.

              Sources:

              World Meteorological Organization, 1970. Climatic Atlas of 
                  Europe, Geneva.
              World Meteorological Organization, 1981. Climatic Atlas of Asia, 
                  Geneva.

              NETHERLANDS--High Confidence. Research suggested that snow cover 
              was not present long enough to maintain a mean monthly snow 
              depth.

              NEW ZEALAND--Low Confidence.

              Sources:

              Fitsharris, B.B., 1978. "problem in Estimating Snow Accumulation 
                  with Elevation on New Zealand Mountains," Journal of 
                  Hydrology, New Zealand, vol. 17, no 1, pp 78-89.
              Landsberg, H.E. (ed.), 1976. World Survey of Climatology Vol. 
                  13, Climates of Australia and New Zealand, Elsevier 
                  Publishing Co., Amsterdam.
              U.S. Central Intelligence Agency, 1960. National Intelligence 
                  Survey, NIS 97, New Zealand, sect. 23, Weather and Climate, 
                  Washington D.C.

              NORWAY--High Confidence.

              Sources:

              Intelligence Division (OUSARMA), 1963. Climatic Conditions in 
                  North Norway, Report Number 2872005563, Oslo, Norway.
              U.S. Central Intelligence Agency, 1960. National Intelligence 
                  Survey, NIS 10, Norway, sect. 23, Weather and Climate, 
                  Washington C.C.

              POLAND--High Confidence.

              Sources:

              Atlas Klimatczny Polski; Opady Atmosferyczne I Pokrywa Sniezna, 
                  Instytut Meteorologii I Gospodarki Wodnej.
              Lewinska, Janina, 1963. Zasoby Wodne Sniegu W Dorzeczu Dunajca I 
                  Metoda 1ch Okreslania, Panstwawego Instytutu Hydrologiczno-
                  Meteorologicznego, Warsaw.
              U.S. Central Intelligence Agency, 1960. National Intelligence 
                  Survey, NIS 14, Poland, sect. 23, Weather and Climate, 
                  Washington D.C.

              PORTUGAL--High Confidence. Research suggested that snow cover 
              was not present long enough here (except on the higher mountain 
              peaks) to maintain a mean monthly snow depth or attempt 
              inclusion in this study.

              ROMANIA--High Confidence.

              Sources:

              U.S. Central Intelligence Agency, 1960. National Intelligence, 
                  Survey, NIS 22-23, Romania and Bulgaria, sect. 23, Weather 
                  and Climate, Washington D.C.

              SPAIN--Low Confidence.

              Sources:

              U.S. Central Intelligence Agency, 1960. National Intelligence 
                  Survey, NIS 9, Spain, sect. 23, Weather and Climate, 
                  Washington D.C.

              SOUTH AMERICA--Low Confidence.

              Sources:

              Landsberg, H.E., ed., 1976. World Survey of Climatology Volume 
                  12, Climates of Central and South America, Elsevier 
                  Publishing Company, Amsterdam.
              U.S. Central Intelligence Agency, 1960. National Intelligence 
                  Survey, NIS 90-91, Argentina and Uruguay, sect. 23, Weather 
                  and Climate, Washington D.C.

              SWEDEN-High Confidence.

              Sources:

              Pershagen, H., 1969. Snow Cover in Sweden, Sveriges 
                  Meteorologiska Och Hydrologiska Institut, Stockholm.

              SWITZERLAND--Fair Confidence.

              Sources:

              Air Ministry Meteorological Office, 1944. Meteorological Report 
                  on the Alps, Supplement 1, London.
              Fohn, P., 1984. Schnee und Lawinen in den Schweizer Alpine 
                  Winter 1982/83, Winterbericht des Eidg., Institutes fur 
                  Schnee und Lawinenforschung, Weissfluhjoch.

              TURKEY--Low Confidence.

              Sources:

              Ministry of Agriculture, 1962. Ortalama ve Ekstrem Kiymetler 
                  Meteoroloji Bulteni, Istanbul.

              UNITED KINGDOM--Fair Confidence.

              Sources:

              US. Central Intelligence Agency, 1960. National Intelligence 
                  Survey, NIS 1-2, United Kingdom and Ireland, sect. 23, 
                  Weather and Climate, Washington D.C.

              USSR--High Confidence.

              Sources:

              Kopanev, I.D., 1978. Snow Cover in the USSR Territory, 
                  Leningrad.

              UNITED STATES--High Confidence.

              Sources:

              Alpine Snow and Avalanche Research Project, U.S. Forest Service, 
                  RM Station, Fort Collins, CO.
              Bolsenga, S.J., 1967. Great Lakes Snow Depth Probability Charts 
                  and Tables, United States Lake Survey, Detroit.
              Climatology of the U.S., 1978. Number 90 (196501974), Airport 
                  Summary, National Climatic Data Center, Asheville.
              "Summary of Day Data" (U.S. AFBs), OL-A, USAFETAC, Asheville.

              YUGOSLAVIA--Low Confidence.

              Sources:

              Air Ministry Meteorological Office, 1945, Meteorological Report 
                  on Yugoslavia and Albania, London.

      10.2.3  Measurement Error for Parameters and Variables.

              Limitations of point measurements as representative of 
              area/regional conditions (i.e. localized drifting, wind re-
              distribution).

      10.2.4  Additional Quality Assessment Applied.

              None.

                                     11.  NOTES

11.1  Known Problems With The Data.

      Quality of the climatology is regional and decreases with the decreasing 
      spatial density of the surface reporting stations contributing to the 
      climatology.  The time periods covered by the input data sets are not 
      consistent, varying across the globe.

11.2  Usage Guidance.

      Same as in section 11.1.

11.3  Other Relevant Information.

      None.

                           12.  REFERENCES

12.1  Satellite/Instrument/Data Processing Documentation.

     Foster, D.J. and R.D. Davy, 1988. Global Snow Depth Climatology, 
         USAFETAC/TN-88/006, Scott Air Force Base, Illinois, 48 p.
     Hoke, J.E., J.L. Hayes, and L.G. Renninger, 1979. Map Projections and 
         Grid Systems for Meteorological Applications, AFGWC/TN-79/003USAF, 
         Air Weather Service, Offutt AFB NE, 68113.

12.2  Journal Articles and Study Reports.

      Bilello, M.A., 1969. Relationships Between Climate and Regional 
          variations in snow-cover Density in North America, U.S. Army Cold 
          Regions Research and Engineering Laboratory, Hanover, NH, 1969.
      Dewey, Kenneth F., 1987. "Satellite-Derived Maps of Snow Cover Frequency 
          for the Northern Hemisphere," Journal of Climate and Applied 
          Meteorology, 26(9):1210-1229.
      Dewey, K.F. and R. Heim, Jr., 1983. "Satellite observations of 
          variations in Southern Hemispheric snow cover." NOAA Technical 
          Report NESDIS 1, U.S. Department of Commerce, Washington D.C.
      Dickson, R.R. and J. Posey, 1967. "maps of snow-cover probability for 
          the Northern Hemisphere," Monthly Weather Review, 95:347-353.
      Hall, S.J., 1986. AFGWC Snow Analysis Model, AFGWC/TN-86/001, AFGWC, 
          Offutt AFB, NE.
      Schutz, C., and L.D. Bregman, 1975. Global Snow Depth Data: A Monthly 
          Summary, The Rand Corporation, Santa Monica.
      U.S. Army Corps of Engineers, Depth of Snow Cover in the Northern 
          Hemisphere, Arctic Construction and Frost Effects Laboratory, New 
          England Division, Boston.
      World Meteorological Office, 1970. Climatic Atlas of Europe, Geneva.
      World Meteorological Office, 1981. Climatic Atlas of Asia, Geneva.

12.3  Archive/DBMS Usage Documentation.

      Contact the EOS Distributed Active Archive Center (DAAC) at NASA Goddard 
      Space Flight Center (GSFC), Greenbelt Maryland (see Section 13 below).
      Documentation about using the archive or information about access to the 
      on-line information system is available through the GSFC DAAC User 
      Services Office.

                             13.  DATA ACCESS

13.1  Contacts for Archive/Data Access Information.

      GSFC DAAC User Services
      NASA/Goddard Space Flight Center
      Code 902.2
      Greenbelt, MD 20771

      Phone:     (301) 286-3209
      Fax:       (301) 286-1775
      Internet:  daacuso@eosdata.gsfc.nasa.gov

13.2  Archive Identification.

      Goddard Distributed Active Archive Center
      NASA Goddard Space Flight Center
      Code 902.2
      Greenbelt, MD 20771

      Telephone:  (301) 286-3209
      FAX:        (301) 286-1775
      Internet:   daacuso@eosdata.gsfc.nasa.gov

13.3  Procedures for Obtaining Data.

      Users may place requests by accessing the on-line system, by sending 
      letters, electronic mail, FAX, telephone, or personal visit.

      Accessing the GSFC DAAC Online System:

      The GSFC DAAC Information Management System (IMS) allows users to 
      ordering data sets stored on-line.  The system is open to the public.

      Access Instructions:

      Node name:  daac.gsfc.nasa.gov
      Node number: 192.107.190.139
      Login example: telnet daac.gsfc.nasa.gov
      Username:  daacims
      password:  gsfcdaac

      You will be asked to register your name and address during your first
      session.

      Ordering CD-ROMs:

      To order CD-ROMs (available through the Goddard DAAC) users should 
      contact the Goddard DAAC User Support Office (see section 13.2).

13.4  GSFC DAAC Status/Plans.

      The ISLSCP Initiative I CD-ROM is available from the Goddard DAAC.

                   14.  OUTPUT PRODUCTS AND AVAILABILITY

14.1  Tape Products.

      None.

14.2  Film Products.

      None.

14.3  Other Products.

      None.

                       15.  GLOSSARY OF ACRONYMS

CD-ROM             Compact Disk (optical), Read Only Memory
DAAC               Distributed Active Archive Center
EOS                Earth Observing System
GCM                General Circulation Model of the atmosphere
GSFC               Goddard Space Flight Center
IDS                Inter disciplinary Science
ISLSCP             International Satellite Land Surface Climotology Project
NASA               National Aeronautics and Space Administration
USAF/ETAC          United States Air Force Environmental Technical 
                   Applications Center