Mediterranean Alpine Experiment

Project Description
The Mediterranean Alpine Experiment (MEDALPEX) formed an additional part of the
Global Atmospheric Research Program (GARP) subprogram on the airflow over and
around mountains. MEDALPEX ran concurrently with the Garp Alpine Experiment
(ALPEX) - over the year from 1 September 1981 to 30 September 1982 with a
special observation period (SOP) from 15 february 1982 to 30 April 1982. The
main aim of ALPEX was to study processes such as lee cyclogenesis and severe
local winds (for example the Mistral and the Bora), which have two frequency
peaks during the year, one in November and the other in April. This was one of
the reasons for the SOP in April.
The Mediterranean is a deep enclosed sea where tides are small and motion is
essentially due to atmospheric forcing. Oceanographic experiments with
simultaneous meterological data collection are necessary for a better
understanding of the dynamics of the Mediterranean and for setting up well
calibrated models. The Mediterranean may also be regarded as a small scale
model of the ocean. Thus studies on the dynamics of gyres, fronts, baroclinic
instabilities, eddies, turbulent dissipation and intermittancy, especially
during storm conditions, can contribute to the understanding of energy
transfers in the ocean and its boundaries. The mesoscale eddies and meanders
which play an essential role in this circulation, forming the summer
thermocline and winter convection may also be studied. All of the above rely
heavily on the spatial and temporal aspects of meterological processes.
The primary function of MEDALPEX was to study the response of the western part
of the Mediterranean to wind forcing. The experiments which took place, often
as part of an individual country's oceanographic research program, were
designed with the intention of increasing understanding of the general problem
of meterological and oceanographic interactions. Specific topics under
investigation included:
i) the interrelationship between the general circulation and mesoscale eddies;
ii) offshore dynamic response mechanisms under severe weather conditions. The
behavior of the Mediterranean under severe weather conditions when
oceanographic ships cannot operate has, until now, yielded only limited
information. MEDALPEX sought to collect data (especially during the SOP) to
give more complete information during periods of bad weather;
iii)storm surges and coastal piling up - for the Adriatic Sea, more detailed
verification of storm surges can be carried out with improved wind field data.
The Ligurian Sea has very small tides but sea level rises and coastal waves
during cyclogenesis damage the coastline. With good wind field, wave and sea
level data, a model may be developed to simulate this.
MEDALPEX was a multinational program with participants from seven countries
(Belgium, France, Italy, Spain, U.K., U.S.S.R and Yugoslavia). A wide range of
oceanographic data, including data from tide gauges, current meters, thermistor
chains, waverider buoys, CTD's and XBT's were collected. Classical and synopt
meterological measurements were made and remote sensing techniques used. The
data resulting from MEDALPEX were to be forwarded to the Responsible National
Oceanographic Data Center (RNODC) - in this case the World Data Center B
(Oceanography) in Moscow - with the exception of the sea level data. The
Permanent Service for Mean Sea Level (PSMSL) undertook to act as the Sea Level
Data Center for MEDALPEX; the data management and banking was carried out by the
Marine Information and Advisory Service (MIAS).