A better characterization of the variability of sea level trends at a regional scale, visible in this example around the British Isles based on 14 years of Jason-1 and Jason-2 data reprocessed with the ALES algorithm, is one of the many objectives of NOCOST.
The NOCOST Project encompasses a range of activities in satellite altimetry proposed by the National Oceanography Centre (NOC), in collaboration with the British Oceanographic Data Centre (BODC), as a contribution to the main goals of the Ocean Surface Topography Science Team (OSTST).
These activities align with some of the OSTST research topics, i.e.:
- studies in physical oceanography, in particular for the coastal ocean and for global and regional sea level variations
- studies of high-resolution altimetry, including the Jason series, as well as other altimetric datasets
- comparative studies among Jason-series missions and other missions, to allow the characterization of the measurement errors, including those that affect estimates of global mean sea level. This topic also includes development and assessment of new geophysical algorithms and/or models likely to improve the quality of the data.
- exploratory studies of operational applications of satellite altimetry for near real-time to interannual weather warnings and forecasts
- studies on extreme sea level and coastal inundation (storm surges)
- preparation for future altimetry missions, in particular Sentinel-6/Jason-CS
The specific objectives of NOCOST are:
- Algorithm development and testing, with special focus on altimetry in the coastal zone and on the intercalibration of conventional and SAR altimetry
- Global and regional sea level studies, and studies on extreme events and coastal inundation (storm surges)
- Application of altimetry to studies of ocean mesoscale and sub-mesoscale processes and their parameterisations in models
NOCOST work builds on several major areas of expertise of the National Oceanography Centre, including:
- global, regional and local sea level studies with satellite altimetry and tide gauges
- calibration/validation of satellite altimeter sea surface height, significant wave height and wind speed against in situ measurements and other satellite missions including SAR altimetry such as Cryosat-2, Sentinel-3
- understanding of the impact of wind and sea state on altimeter measurements, particularly through sea state bias at and off-nadir
- developing techniques for improved altimetric observations in the coastal zone, and the relevant applications
- experimental observing and modelling capability of ocean mesoscale and sub-mesoscale processes in the open ocean and shelf-seas
- scientific lead in the development and exploitation of new ocean observing capabilities, such as those based on along-track SAR interferometry and GNSS-reflectometry.
NOC is in an unique position to carry out these investigations by virtue of its staff expertise built over decades of involvement in satellite altimetry, sea level science and open ocean and coastal modelling, combined with state of the art computing facilities and first-hand access to a vast range of in situ oceanographic measurements.
This NOCOST Project is highly complementary and synergistic with the activities presented by NOC in the VORTICES proposal to the SWOT Science Team (Cipollini and Gommenginger, 2016). In particular we expect the additional knowledge about the oceanic sub-mesoscale and coastal dynamics that is going to be acquired through NOCOST, combined with the consolidated NOC expertise in high-resolution SAR altimetry and along-track SAR interferometry, to support the interpretation of the results from the calibration and validation activities of SWOT proposed in VORTICES.