POTENTIAL EVAPOTRANSPIRATION

Data ID

Description:

Potential evapotranspiration

Chapter:

Additional data

File name:

pet

File type:

ArcView shapefile

Geographical area:

Namibia

Keywords:

evapotranspiration

evaporation

water

Notes on data, analysis and

Potential Evapotranspiration (PET) is a concept widely used in Agrometeorology to indicate the water requirements of

compilation:

crops, rangeland or natural vegetation. It represents a combination of the potential evaporation from the soil and the

transpiration of the crops calculated according to the relevant weather conditions. The weather elements that are used

to calculate the PET are solar radiation, air temperature, wind speed and humidity of the atmosphere. Often, data for

these elements are not available, and proxies must be used, for example, duration of sunshine instead of solar radiation.

The polygons making up the shapefile were created from hand drawn contours on a hard copy map. This manual

interpolation approach was done by Peter Hutchinson using the point data from all available stations. Because the

number of stations was small (26) an automatic interpolation produced nonsense results. Data were taken from the

Agro-ecological zone project (Ministry of Agriculture, Water and Rural Development).

Data quality and organisation

Positional Accuracy:

Low

Vector/Raster:

Vector

Spatial reference

Projection:

Geographic

Fields

Field name

Field description

PET_CLASS

Potential evapotranspiration in mm/month

RANK	Rank of 1 to 10 representing low to high potential

evapotranspiration

Source/Distribution

Data Source:

Agro-ecological Zone project

Contact:

Marina Coetzee

Online/Offline Address:

Ministry of Agriculture, Water and Rural Development

Private Bag 13184

Windhoek

Distribution notes:

Unrestricted