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F. Gottsche, F.-S. Olesen
temperature maps become noisy. Most synoptic artefacts are eliminated in the
modelled temperatures; in this respect, the results for median composites are
supenor.
It is now assumed, that the determined model parameters reflect thermal surface
properties. The parameters for the maximum composites describe the hottest
situation, whereas the ones for the median composites describe the typical
(average)situation and characterise the more permanent surface properties better.
Furthermore, in maximum composites hot regions "grow" on the expense of colder
ones; this leads to some loss of dynamics. Fig. 4 shows modelled temperatures for
August 1996 at 12:30 hours UTC for most ofItaly.
The model of the DTC was fitted to median and maximum composites of the
vegetation period of 1996, which were generated for each month, pixel, and slot.
This resulted in two data sets of synthetic DTC' s per month, covering the northern
Sahara as well as vegetated areas in Germany up to the Danish border. However, the
parameters To and Ta proved to be noisier than those of maximum temperature
To+ TO' This is due to the high temperature gradients in the early morning which
limit the accuracy of To and, as a consequence, also of Ta. Therefore, instead of
using To and Ta directly, the 'corrected' residual temperature To +oT and the
'corrected' temperature amplitude Ta - oT are discussed, which are the temperature
the model reaches for t-+oo and the amplitude in relation to this value, respectively.
Due to the small gradient of the model for t» t5 the uncertainties of these quantities
are low. Fig. 5 shows To+OT and Ta -
to median (left) and maximum (right) composites for August 1996. No obvious synoptic artefacts can
be observed. The temperatures obtained from the maximum composites reflect the hottest situations
during the composition interval; while highlighting areas, where high temperatures occurred, they also
"flatten" some details, i.e. on Sicily. In contrast, the temperatures obtained from the median
composites reflect the typical values during the composition interval and show more details in the
colder range.
F. Gottsche, F.-S. Olesen
temperature maps become noisy. Most synoptic artefacts are eliminated in the
modelled temperatures; in this respect, the results for median composites are
supenor.
It is now assumed, that the determined model parameters reflect thermal surface
properties. The parameters for the maximum composites describe the hottest
situation, whereas the ones for the median composites describe the typical
(average)situation and characterise the more permanent surface properties better.
Furthermore, in maximum composites hot regions "grow" on the expense of colder
ones; this leads to some loss of dynamics. Fig. 4 shows modelled temperatures for
August 1996 at 12:30 hours UTC for most ofItaly.
The model of the DTC was fitted to median and maximum composites of the
vegetation period of 1996, which were generated for each month, pixel, and slot.
This resulted in two data sets of synthetic DTC' s per month, covering the northern
Sahara as well as vegetated areas in Germany up to the Danish border. However, the
parameters To and Ta proved to be noisier than those of maximum temperature
To+ TO' This is due to the high temperature gradients in the early morning which
limit the accuracy of To and, as a consequence, also of Ta. Therefore, instead of
using To and Ta directly, the 'corrected' residual temperature To +oT and the
'corrected' temperature amplitude Ta - oT are discussed, which are the temperature
the model reaches for t-+oo and the amplitude in relation to this value, respectively.
Due to the small gradient of the model for t» t5 the uncertainties of these quantities
are low. Fig. 5 shows To+OT and Ta -
to median (left) and maximum (right) composites for August 1996. No obvious synoptic artefacts can
be observed. The temperatures obtained from the maximum composites reflect the hottest situations
during the composition interval; while highlighting areas, where high temperatures occurred, they also
"flatten" some details, i.e. on Sicily. In contrast, the temperatures obtained from the median
composites reflect the typical values during the composition interval and show more details in the
colder range.