is an IOC/CIESM pilot project that is building an operational sea
level monitoring network system for systematic measurements in the Mediterranean
and Black Seas. The system is based on the basic GLOSS requirements and
methodology, aiming to provide for the first time a high quality standardized
data on sea level in near real-time with a coverage along the Mediterranean
and Black Sea basins.
level monitoring is important for studies on global climate change
and sea level rise. A worldwide eustatic sea-level rise has been
forecasted by the WMO/UNEP Intergovernmental Panel on Climate Change
(IPCC) with major factors causing this sea-level rise being the
ocean water volume expansion and ice cap melting due to global warming.
From the regional perspective sea-level rise may differ significantly
from the globally averaged sea-level rise forecasts, in particular
due to tectonic movements.
Simultaneous absolute sea level
observations taking account of geodetic movements and with sufficient
spatial coverage are thus necessary to better understand the signals
of sea level trends and variability in the region.
marina control tower hosting the Malta MedGLOSS station base
Sustained simultaneous hydro-meteorological
measurements covering the whole region will also open the way for a comprehensive
study of the basin and sub-basin responses of the water body to external
forcing. The extensive geographical coverage and duration of observations
will permit the identification of commonalities and differences in mechanisms
responsible for long wave signals that have regional scale signatures
as compared to those occurring on the shelf and in the coastal areas,
as well as enable to study the dependencies of the latter smaller spatial
scale oscillations on the regional scale dynamics and basin wide influences
On a more local scale the use of the
sea level data is essential for shipping and harbour operations, for the
impact of storm surges, for studies on salt intrusion in aquifers, for
the estimation of extreme sea levels in connection with the building of
coastal structures, and other applications. When a sufficiently long data
series becomes available it is also possible to model the effect of wind
and atmospheric pressure on the mean sea level on a local scale and hence
permit a more precise prediction of sea levels including the prediction
Malta hosts one of the node stations
of the MedGLOSS Network. The installation of sea level gauge was completed
in February 2001 in the Portomaso marina at the Malta
Hilton in St. Julians and constitutes the first real-time monitoring
station for oceanographic data in Malta. The instrument, donated by the
for the Scientific Exploration of the Mediterranean Sea (CIESM), collects
sea level data (every half-a-minute), seawater temperature, atmospheric
pressure and waves in the marina.
marina and instruments -
Click image to enlarge
Hourly averaged observations are shared in real-time
with the MedGOOS network through the Israel
Oceanographic and Limnological Research (IOLR) that co-ordinates
and controls the project. These data are presented in twice-daily
updated graphical representation on this website (click
here for update). Data are also achieved at the Permanent
Service for Mean Sea Level (PSMSL) centre in Bidston, UK which
is the global data bank for long term sea-level change information
from tide gauges.
Malta, together with Israel, was instrumental
within CIESM to promote and prepare the launching of MedGLOSS.
It is envisaged that Malta will also host a GPS MedGLOSS station
in the near future, and to become a regional centre for the Central
Description of the Malta
The equipment of the station includes:
- an underwater pressure sensor of Paroscientific
manufacture, type Digiquartz Intelligent sensor, model 8DP060-1 with
an RS-232 communication cable
- Setra atmospheric pressure sensor, type 470
- Trimble GPS timer computer card and antenna for
accurate time recording
- Computer serving to process and store data
- Server to interrogate and transmit data in real-time
The ISRAMAR package of computer programmes integrated
in a unified system provides near real-time data gathering and transmissions.
At the receiving end, the software automatically controls the quality
of the data received for the MedGLOSS station, including automatic regular
submission of status to the operator by email messaging.
The underwater sensor is 10cm in diameter and 25cm long. It is
housed in a stainless steel protective frame whose diameter is
15cm and 60cm long. It is attached to a 1” diameter stainless
steel rod which is approximately 1m long. The rod is inserted
underwater into a vertical stainless steel tube slightly larger
than 1” inner diameter, welded to a horizontal stainless
rod, which is attached to a steel plate (40cm x 40cm x 2cm) found
attached to the quay in situ at about 3m (in a total depth of
3.5m) below sea level.
Setra 470 Digital Pressure Transducer is a highly accurate pressure
measurement system, utilizing the patented SETRACERAMTM sensor,
advanced micro-computer based electronics, and sophisticated firmware.
The Setra 470 accurately measures and reports barometric pressure.
The digital design of the Setra 470 provides a simple and reliable
communications interface for easy integration into digital control
systems. This, in addition to the digital signal processing of the
sensing element signal, allows the elimination of inaccuracies and
cost of an analogue data acquisition module.
Maintenance of Equipment
The underwater sensor is cleaned regularly. The process
includes the cleaning of the underwater pressure sensor and its orifice,
and its underwater cable. The atmospheric pressure sensor is cleaned of
dust once in a few months. Recalibration of the underwater sensor is done
at least once every 2 years at the mother company.
Description of data and real time transmission
|The sea level station registers
data every half minute on a computer on site. This computer communicates
data with a server at the University of Malta. The sea level station
is interrogated every hour by the server. The shortest packet of data
is on the first hour of the day.Successive
hours transmit also
the previous hourly data packets of the day. The largest packet
is on the 24th hour and is about 1K in size. This daily cycle of
data transmission is fully automated.
Daily files and charts of hourly averaged values of sea-level,
water temperature and atmospheric pressure are available from this
Agencies which are interested to subscribe for
direct access to the data can contact Dr. Aldo Drago (responsible
for the Malta MedGLOSS station).
and real time transmission system
image to enlarge
MedGLOSS Pilot Network____
The pilot network was initially planned
to include some 27 stations in 13 countries which have expressed their
interest in joining this international research network. It includes the
five GLOSS sea-level monitoring stations operating in the region.
of MedGLOSS pilot network of sea level stations (originally planned
image to enlarge
So far MedGLOSS sea level stations have
been established in Costanta (Romania), Dubrovnik (Croatia), Portomaso
(Malta) and Paphos (Cyprus). The Katcively sea-level station in Ukraine
is the next in line to be upgraded to MedGLOSS standard in early 2003.
Contacts with NIOF (Egypt) and (FSR) Morocco are in hand and new installations
at these two important locations are being considered.