The Copernicus Marine Environment Monitoring Service Ocean State Report

Abstract

The Copernicus Marine Environment Monitoring Service (CMEMS) Ocean State Report (OSR) provides an annual report of the state of the global ocean and European regional seas for policy and decision-makers with the additional aim of increasing general public awareness about the status of, and changes in, the marine environment. The CMEMS OSR draws on expert analysis and provides a 3-D view (through reanalysis systems), a view from above (through remote-sensing data) and a direct view of the interior (through in situ measurements) of the global ocean and the European regional seas. The report is based on the unique CMEMS monitoring capabilities of the blue (hydrography, currents), white (sea ice) and green (e.g. Chlorophyll) marine environment. This first issue of the CMEMS OSR provides guidance on Essential Variables, large-scale changes and specific events related to the physical ocean state over the period 1993–2015. Principal findings of this first CMEMS OSR show a significant increase in global and regional sea levels, thermosteric expansion, ocean heat content, sea surface temperature and Antarctic sea ice extent and conversely a decrease in Arctic sea ice extent during the 1993–2015 period. During the year 2015 exceptionally strong large-scale changes were monitored such as, for example, a strong El Niño Southern Oscillation, a high frequency of extreme storms and sea level events in specific regions in addition to areas of high sea level and harmful algae blooms. At the same time, some areas in the Arctic Ocean experienced exceptionally low sea ice extent and temperatures below average were observed in the North Atlantic Ocean

An improved and homogeneous altimeter sea level record from the ESA Climate Change Initiative

“…But until recently, it was considered that the TOPEX-A drift had minimal impact on the GMSL. Based on a comparison between TOPEX-A sea level and tide gauge data, Valladeau et al (2012) challenged this conclusion but did not quantify this effect on the GMSL. More recently, three studies have attempted to quantify the effect of the TOPEX-A drift on the GMSL trend over the period January 1993-December 1998.…”

“…Compared with the v1.1 ECV, a small difference is observed in terms of the amplitude (1 mm). It is assessed by comparison with tide gauge measurements (Valladeau et al, 2012). The amplitude of the annual cycle of the sea level difference computed against predominantly coastal in situ data reaches 2.4 mm with the v1.1 ECV and is reduced to 1.6 mm with the v2.0 ECV, suggesting that the annual signal is better retrieved with the reprocessed dataset.…”

“…For the v2.0 GMSL, the same trend of 3.3 mm yr −1 is found for the 1993-2003 and 2005-2015 altimetry decades, indicating a steady rise of the GMSL. However, several recent studies using different approaches suggest that an instrumental drift has affected the TOPEX-A altimeter measurements during 1993(Valladeau et al, 2012Watson et al, 2015;Dieng et al, 2017;Beckley et al, 2017). The instrumental drift of the TOPEX-A altimeter has long been known (Hayne and Handcock, 1998), leading to the switch early 1999 to the redundant TOPEX-B altimeter.…”

“…2). In this area, trends are mainly of thermosteric origin (Legeais et al, 2016b;Meyssignac et al, 2017) in response to increased easterly winds during the last 2 decades associated with the decreasing Interdecadal Pacific Oscillation (IPO)/Pacific Decadal Oscillation (e.g. Merrifield et al, 2012;Palanisamy et al, 2015a;Rietbroek et al, 2016).…”

Towards the Marine Arctic Component of the Pan-Eurasian Experiment

“…To respond to this need, the Copernicus Marine and Atmospheric Services have since 2014 provided monitoring and short-term forecasting on global scale, including the Arctic (von Schuckmann et al, 2016). The services use various models, satellite data and available in situ data that are delivered in near real-time.…”