ll"
quan-
pro-
amples
al
: heat
les
ro con
above
the
S of
ing
rained
ss.
Heating gradient and temperatures before sunrise
The objective was to find a method which emphasizes soil characteris-
tics (peaty soil with constant water contents) and which neglects the
land use pattern. In fig. 9 the heating gradients are plotted versus
the temperatures before sunrise. The ratio values of all classes form
a large cluster.
The diagram in fig. 9 shows, too, that this is especially due to the
temperatures before sunrise. Differentiations within the temperature/
soil unit can be made utilizing the temperature gradients.
The map of temperature gradients
By the above method a map of the heating gradients was designed. This
was done, because the comparison between map and nature is the only way
to test the geoscientific usefullness of mathematic-statistic procedures.
The map in fig. 10 consists of three main areas with basic temperatures
(temperatures before sunrise) B (6,25 - 7,5 °c) GC (7,5 - 8,75 °c); at
about 3/4 of the whole mapped area) and D (8,75 - 10 ?c). High basic
temperature and.low gradient indicate high moisture contents. The re-
lative large differences in the mapped area must be caused by diffe-
rent vegetation because soil properties are similar for all fields.
This effect results from the addition of the influences of soil moisture
and vegetation.
The unmown fields of the well drained area show the same gradient as
the swamp. This is obviously the effect of the high grass; evapo-
transpiration lowers surface temperatures during daytime, contrasting
thus the mown fields. Thus the lower gradient simulates a higher
moisture.
The upper left part of the map (fig. 10) differs much from the described
areas. Situated between swamp and grassland it shows the lowest basic
temperatures (A and B) and the highest gradients. This area rises slowly