Geographically, two-thirds of Bangladesh lies in a vast deltaic plain, formed at the mouth of the
Ganges, Brahmaputra and Meghna rivers (GBMD). This delta is the largest and most populated in
the world, covering approximately 150,000 km² and home to more than 150 million inhabitants.
Floods are frequent, and each year, during the summer monsoon, between 20% and 60% of the
country is submerged. In the face of current and future climate disruption, IPCC projections
predict in the GBMD: an intensification of floods and extreme events, as well as a worrying rise in
mean sea level relative to land elevation. Today, more than 10% of the GBMD is less than one
meter above mean sea level and land therein is subsiding, as in the largest deltas of the tropical
areas. The future of the GBMD and its ability to remain above water depend on a delicate balance
between sea level rise and land subsidence. Quantifying these parameters is essential to guide
local policies and adapt strategies to climate change. However, the data available to analyze these
phenomena are still very limited in Bangladesh and virtually no data is transmitted to decision-
making institutions in real time. This new project, called “Partnership for Ocean Level
Monitoring” (POLM), has the main objective of strengthening the technical capacities for
observing variations in sea level rise and land level. It is based on the use of "Global Navigation
Satellite System" (GNSS) stations, i.e. all satellite positioning systems, to determine in a coupled
manner the water level (by Interferometry Reflectometry, IR, method) and the land level. Our
project aims to technically support the national institutes dedicated to the study of these
parameters and involved in the management of climatic hazards, through: 1. deploying innovative
and affordable instrumentation tools; 2. establishing a real-time data transfer network; and 3.
contributing to the training of the actors of these institutes, in particular the new generation of
female scientists. POLM will enable several proofs of concept adapted to the economic and
technical realities of Bangladesh, in particular: a low-cost assembly of stations, which reduces
costs by ~50%; and the use of 4G networks, well adapted to the country's satellite coverage, to
ensure real-time data transmission. Preliminary results from the analysis of the collected water
level measurements, their processing and quality assessment, will be presented, as well as their
experimental utilization in numerical models for the representation of the sea level dynamics. Thisproject is part of an international scientific effort to collect coastal oceanographic data, necessary
for monitoring global sea level and for predicting ocean rise by regional models.

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