Climate, Climate Variability and Impacts in the Mediterranean Area: An Overview
85
them into a new level of understanding and monitoring of processes. This
aggregation often can be accomplished by models. EFEDA-type experiments per se,
mainly because of their short duration, do not solve environmental problems,
sometimes they indicate where problems may arise, but their main benefit is that
they develop and prove new approaches and methodologies how to attribute changes
to the "Global Change" problem. The problem is not to provide experimenters with
additional data but to gather and analyse those data which have been identified by
EFEDA-type experiments in a quasi-operational manner for time scales which are
recognized as essential to isolate trends from interannual variability.
In an continuation of the efforts started with EFEDA and especially if it is
desired to transform this approach into a large scale GEWEX-type study it would be
necessary to gather in addition to meteorological and hydrological routine
measurements at a certain number of "anchor stations" placed into representative
areas around the Mediterranean and to merge the data of the operational system with
this scientific network. The emphasis of the "anchor stations" must lie on those
quantities which are not measured by the operational network. In the past there have
been often a misunderstanding in this respect as standard climatological equipment
was offered as "anchor station". But it is now feasible to infer from satellite
measurements in addition to the "primary" quantities like surface reflectance,
surface temperature, and various vegetation indices also information such as on
vegetation quantities, fluxes between surface and atmosphere, and soil top moisture.
These "secondary level" data, which are in the first instance Land-surface Change
Indicators need to be "clamped" to reality by continuous observations at anchor
stations - and from time to time field experiments to remove uncertainties - to enfold
the whole observing potential of measurements made from space.
Considering the use of satellites it is mandatory that
atmospheric data (three dimensional temperature, pressure, water vapor and
aerosol fields) become available in quasi real time which allow in combination
with topographic models to correct the measurements made in space for
atmospheric effects, and
that anchor stations be established around the Mediterranean Sea to continuously
control at representative points the validity of the information deduced from the
satellite measurements.
To embed short term EFEDA-type experiments into long term developments it
is essential to obtain in addition to operationally available data also those data which
are not operationally archived and are needed especially to expand local
measurements into area averages. It is not as important if a few hectare of
unmanaged forest burns down in an area where the environmental conditions allow
a fast regrowth as it is if a large agricultural area slowly gets into an irreversible
permanent water shortage situation because of extended droughts during the
summers and not enough winter rain to compensate for the water evaporating during
summer and extracted for households, irrigation, industry and tourism.
85
them into a new level of understanding and monitoring of processes. This
aggregation often can be accomplished by models. EFEDA-type experiments per se,
mainly because of their short duration, do not solve environmental problems,
sometimes they indicate where problems may arise, but their main benefit is that
they develop and prove new approaches and methodologies how to attribute changes
to the "Global Change" problem. The problem is not to provide experimenters with
additional data but to gather and analyse those data which have been identified by
EFEDA-type experiments in a quasi-operational manner for time scales which are
recognized as essential to isolate trends from interannual variability.
In an continuation of the efforts started with EFEDA and especially if it is
desired to transform this approach into a large scale GEWEX-type study it would be
necessary to gather in addition to meteorological and hydrological routine
measurements at a certain number of "anchor stations" placed into representative
areas around the Mediterranean and to merge the data of the operational system with
this scientific network. The emphasis of the "anchor stations" must lie on those
quantities which are not measured by the operational network. In the past there have
been often a misunderstanding in this respect as standard climatological equipment
was offered as "anchor station". But it is now feasible to infer from satellite
measurements in addition to the "primary" quantities like surface reflectance,
surface temperature, and various vegetation indices also information such as on
vegetation quantities, fluxes between surface and atmosphere, and soil top moisture.
These "secondary level" data, which are in the first instance Land-surface Change
Indicators need to be "clamped" to reality by continuous observations at anchor
stations - and from time to time field experiments to remove uncertainties - to enfold
the whole observing potential of measurements made from space.
Considering the use of satellites it is mandatory that
atmospheric data (three dimensional temperature, pressure, water vapor and
aerosol fields) become available in quasi real time which allow in combination
with topographic models to correct the measurements made in space for
atmospheric effects, and
that anchor stations be established around the Mediterranean Sea to continuously
control at representative points the validity of the information deduced from the
satellite measurements.
To embed short term EFEDA-type experiments into long term developments it
is essential to obtain in addition to operationally available data also those data which
are not operationally archived and are needed especially to expand local
measurements into area averages. It is not as important if a few hectare of
unmanaged forest burns down in an area where the environmental conditions allow
a fast regrowth as it is if a large agricultural area slowly gets into an irreversible
permanent water shortage situation because of extended droughts during the
summers and not enough winter rain to compensate for the water evaporating during
summer and extracted for households, irrigation, industry and tourism.