African 6K Land Surface Conditions: Readme file
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                   NOAA Paleoclimatology Program
                                 and
               World Data Center for Paleoclimatology, Boulder
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NOTE: PLEASE CITE ORIGINAL REFERENCE WHEN USING THIS DATA!!!!!

NAME OF DATA SET: African 6K Land Surface Conditions

LAST UPDATE: 5/2000.  New versions of sah_6k.txt and sah_6k.xls.
These replace the original 3/98 versions of these files.  

CONTRIBUTORS: Hoelzmann, P., Jolly, D., Harrison, S.P., Laarif, F.,
Bonnefille, R., Pachur, H.-J..

IGBP PAGES/WDCA Data Contribution Series #:  98-012

SUGGESTED DATA CITATION: Hoelzmann, P.; Jolly, D.; Harrison, S.P.; Laarif, F.
Bonnefille, R., Pachur, H.-J., 1998, African 6K Land Surface Conditions.
IGBP PAGES/World Data Center-A for Paleoclimatology 
Data Contribution Series # 98-012.  
NOAA/NGDC Paleoclimatology Program, Boulder CO, USA.

ORIGINAL REFERENCE:
Hoelzmann, P.; Jolly, D.; Harrison, S.P.; Laarif, F.; Bonnefille, R.;
Pachur, H.-J. (1998): Mid-Holocene land-surface conditions in northern
Africa and the Arabian Peninsula: A data set for the analysis of
biogeophysical feedbacks in the climate system. Global Biogeochem. Cycles
Vol. 12, No. 1, p. 35-52.

GEOGRAPHIC REGION: North Africa, Arabian Peninsula
PERIOD OF RECORD: Present to 6000 yr BP 
LIST OF FILES: africa6k.readme (this file), sah_6k.xls (Microsoft Excel 7.0), 
sah_6k.txt(tab-delimited ASCII text).  Data files updated 25 May 2000.
 
DESCRIPTION:
The dataset describes land-surface conditions at 6000 years B.P. on a 1° x 1° grid
across northern Africa and the Arabian Peninsula. It includes information
on the percentage of each grid cell occupied by specific vegetation types
(steppe, savanna, xerophytic woods/scrub, tropical deciduous forest, and
tropical montane evergreen forest), open lakes, and wetlands, plus
information on the flow direction of major drainage channels. 

sah_6.xls is a dataset covering Northern Africa and the Arabian Peninsula between 
10°N to 30°N and 17°W to 60°E containing data on the areal extent of different 
elements. The file contains a "field" of data, organized in columns (vertical) and 
rows (horizontal). The first row is the header and the first column gives the 
"recognition code" for each grid cell. Each row refers to one grid cell which 
has a spatial resolution of one degree latitude by one degree longitude. 
The latitude/longitude refers to the position of the center of the cell. 
Cells without land coverage (equal to 100% sea) are not included in the data set. 
There are 1431 rows of data each representing one grid cell with a fraction of land. 
The values in the field refer to percentages of the terrain surface. 
In the following the columns are described from left to right.

RECN		recognition code of  grid cell
LATI		latitude in degrees N (dec.)
LONG		longitude in degrees (dec.): negative values refer to grid cells west of the Greenwich meridian
SEA_		percentage of the grid cell covered by ocean
LAKE		estimated % occupied by lakes
WETL		estimated % occupied by wetland
PDD_		paleodrainage direction; 0=uncoded; 1=north; 2=northeast; 3=east; 4=southeast; 5=south; 
6=southwest; 7=west; 8=northwest

The values in the following columns refer to percentages of the terrain surface 
(lake and wetland areas being excluded) occupied by the vegetation

STEPPE		estimated % occupied by steppe
SAVANNA	estimated % occupied by savanna
XERO		estimated % occupied by xerophytic woods/scrub
TDFO		estimated % occupied by tropical deciduous forest
TMEF		estimated % occupied by tropical montane evergreen forest