82
H.-J. Bolle
Appendix 1
The ECHIVAL Field Experiment in Desertification
Threatened Areas (EFEDA)
EFEDA, the "ECHIV AL Field Experiment in Desertification-threatened Areas" was
initiated by the former CEC in response to the international activity on land-surface
processes started by the International Satellite Land-Surface Climatology Project
(ISLSCP) and the Hydrologic Atmospheric Pilot Experiment (HAPEX) initiative of
the World Climate Research Programme. The basis for the EFEDA Experiment plan
was the European International Project on Climatic and Hydrological Interactions
between Vegetation, Atmosphere, and Land-surfaces (ECHIV AL) developed by
Andre, Bolle and Shuttleworth (1989). A related field experiment was carried out
in Crete (Messara Valley Project). The experiments were organised according to the
strategy developed by ISLSCP (Becker, Bolle, and Rowntree, 1988) and
subsequently adopted by IGBP-BAHC (1993).
EFEDA was designed as a multidisciplinary activity to improve our
understanding of climate related land-surface processes in semi-arid areas which
suffer from desertification. Its primary goal was the investigation of the transfer of
water between soils, vegetation, the atmospheric boundary layer and the free
troposphere as well as the assessment of the importance of this chain of processes
for land-degradation and desertification. The experiment the first time combined the
forces of European geologists, soil scientists, hydrologists, geographers, botanist,
ecologists, atmospheric boundary layer researchers, aeronomists, modellers, remote
sensing specialists, and socia-economists including a NASA and a German
instrumented research aircraft and German motorgliders. The first time in the
Mediterranean region the full range of water transfer processes from sub-surface
transports up into the free troposphere have been studied within one experiment. In
addition socia-economic aspects such as the overexploitation of water resources due
to water abstraction for other regions and irrigation had to be taken into account,
because the water cycle in these regions cannot be investigated without considering
the impact of man's actions. To be able to compare the results with the output of
wide meshed climate models and to contribute to an improvement of these models
the experiment had to span over an area compatible with the grid width of climate
models. The first short term pilot field experiment was carried out in June 1991 in
the plains and adjacent smooth hills of Castilla-La Mancha, Spain, that offered an
existing infrastructure and little complication by topographic effects (Bolle et al.,
1993). The area was revisited by part of the experimental team in summer 1994.
Part of the experiment was a remote sensing activity (a) to assist in the aggregation
over the whole experimental area of parameters needed to model land-surface
processes and energy fluxes which at the ground were measured only at individual
points, and (b) to explore the capability of presently available remote sensing data
to quantify changes at the land surfaces, specifically land degradation and
desertification. These remote sensing activities found a continuation in the EC
Projects RESRAPS (1994), RESMEDES (1998), and RESYSMED (1999).
H.-J. Bolle
Appendix 1
The ECHIVAL Field Experiment in Desertification
Threatened Areas (EFEDA)
EFEDA, the "ECHIV AL Field Experiment in Desertification-threatened Areas" was
initiated by the former CEC in response to the international activity on land-surface
processes started by the International Satellite Land-Surface Climatology Project
(ISLSCP) and the Hydrologic Atmospheric Pilot Experiment (HAPEX) initiative of
the World Climate Research Programme. The basis for the EFEDA Experiment plan
was the European International Project on Climatic and Hydrological Interactions
between Vegetation, Atmosphere, and Land-surfaces (ECHIV AL) developed by
Andre, Bolle and Shuttleworth (1989). A related field experiment was carried out
in Crete (Messara Valley Project). The experiments were organised according to the
strategy developed by ISLSCP (Becker, Bolle, and Rowntree, 1988) and
subsequently adopted by IGBP-BAHC (1993).
EFEDA was designed as a multidisciplinary activity to improve our
understanding of climate related land-surface processes in semi-arid areas which
suffer from desertification. Its primary goal was the investigation of the transfer of
water between soils, vegetation, the atmospheric boundary layer and the free
troposphere as well as the assessment of the importance of this chain of processes
for land-degradation and desertification. The experiment the first time combined the
forces of European geologists, soil scientists, hydrologists, geographers, botanist,
ecologists, atmospheric boundary layer researchers, aeronomists, modellers, remote
sensing specialists, and socia-economists including a NASA and a German
instrumented research aircraft and German motorgliders. The first time in the
Mediterranean region the full range of water transfer processes from sub-surface
transports up into the free troposphere have been studied within one experiment. In
addition socia-economic aspects such as the overexploitation of water resources due
to water abstraction for other regions and irrigation had to be taken into account,
because the water cycle in these regions cannot be investigated without considering
the impact of man's actions. To be able to compare the results with the output of
wide meshed climate models and to contribute to an improvement of these models
the experiment had to span over an area compatible with the grid width of climate
models. The first short term pilot field experiment was carried out in June 1991 in
the plains and adjacent smooth hills of Castilla-La Mancha, Spain, that offered an
existing infrastructure and little complication by topographic effects (Bolle et al.,
1993). The area was revisited by part of the experimental team in summer 1994.
Part of the experiment was a remote sensing activity (a) to assist in the aggregation
over the whole experimental area of parameters needed to model land-surface
processes and energy fluxes which at the ground were measured only at individual
points, and (b) to explore the capability of presently available remote sensing data
to quantify changes at the land surfaces, specifically land degradation and
desertification. These remote sensing activities found a continuation in the EC
Projects RESRAPS (1994), RESMEDES (1998), and RESYSMED (1999).