Time-series Data

 

Long-term data: Why, where, how?

 

An understanding of physical, chemical and biological processes in the oceans requires regular and long-term observations. Only with such temporally extensive data sets can we separate real long-term trends in environmental drivers (e.g. a rise in temperature or decreasing pH) and their long-term biological consequences from the random (natural) variation that is a key feature of all complex systems.


Oceanic and coastal time series are therefore an invaluable tool for marine scientists and have been established in many locations around the world since the beginning of the 20th century, with the majority having been initiated from the 1950s onwards. These time series were initially concentrated in coastal regions as they were operated by marine stations (e.g. Plymouth, the Biological Station Helgoland and the Stazione Zoologica Anton Dohrn, to name but a few). These time series generate a range of data usually including temperature and salinity as a minimum, but in addition many also collect biological samples to study the abundance and diversity of marine organisms, such as phyto-and zooplankton, fish or benthic organisms. In combination, these data facilitate studies not only of how these assemblages are affected by their physical and chemical environment but also how this environment shapes biological interactions in the long-term.

 

With respect to station-based time series there are many good examples in the North Sea and North Atlantic, for instance the Helgoland Roads time series in the German Bight which was established in 1962, the Western Channel Observatory off Plymouth, established in 1903, or Hydrostation ‘S’ which started its measurements in the Sargasso Sea near Bermuda in 1957 (although operated by a marine station this is not really a coastal time series). All of these collect physical and chemical data as well as measuring different biological parameters (for more examples see list below).

 

An excellent example of a both spatially and geographically very extensive time series is the Continuous Plankton Recorder survey.  It operates CPR units on ships of opportunity and by now its time series, the oldest of which started in 1937, are covering a large part of the North Atlantic, and more recently the Pacific Ocean and other parts of the world ocean. There are also a number of cruise programmes that follow the same track on a regular basis over long periods of time, to collect time-series data on large spatial scales. The Atlantic Meridional Transect (AMT), which has been running since 1995, is a prime example of this type of spatially- and temporally-extensive sampling programme. 

 

Increasingly, as technology facilitates the installation of sensors that can operate largely unattended for extended periods of time, arrays of measuring devices are also being established in offshore locations and in the deep sea. The deep sea observatory at the Hausgarten for instance has now been operating for almost 14 years. Several projects are now devoted to the installation and management (including data management) of global networks of automated measuring devices including OceanSites for the deep sea and ARGO. Although these automated measuring devices relieve scientists of the need for labour and time intensive manual counts and measurements, their operation is nevertheless very costly (ship time and the equipment itself). Thus, such technologically advanced equipment is beyond the means of most developing countries. Capacity building, through investment in new technologies for developing countries, as well as training in the use of this equipment, aims to redress this imbalance between the developed and developing worlds.

 

The ongoing anthropogenic climate change has certainly increased the scientific interest in time series analyses and their importance is increasingly also recognized at a political level. Many data centres globally are now concerned with the long-term preservation of newly generated data and the retrieval of historic data sets that have not yet been properly curated. The challenge for scientists around the world is now the integration and analysis of these often complex data sets.

 

Below is a preliminary list of projects involving fixed-point time-series measurements with on-line data, and links to the relevant websites.

 

Name Location Position Dates Website Notes
Pacific Ocean 
Tropical Atmosphere Ocean project TAO/TRITON Tropical Pacific 110°W to 165°E; 10°N to 10°S 1979-pres Link Part of OceanSITES
WHOTS (WHOI Hawaii Ocean Time-series Station) Central Pacific 22°45'N; 158°W 2004-pres Link Part of OceanSITES
HOT (Hawaii Ocean Time-series) Station ALOHA  Central Pacific 22°45'N; 158°W 1988-pres Link Part of OceanSITES 
MOSEAN (Multi-disciplinary Ocean Sensors for Environmental Analyses and Networks) E Pacific 22°N; 158°W and 34°N; 119°W 2004-2007 Link  
LOBO (Land/Ocean Biogeochemical Observatory) Monterey Bay/ Elkhorn Slough 36°49′N; 121°44'W 2003-pres Link  
OASIS:Ocean Acquisition System for Interdisciplinary Science  E Pacific/ Monterey Bay 37°N; 122°W 1989-pres Link  
Atlantic Ocean 
Stratus Project Tropical W Atlantic 20°S; 85°W 2000-pres Link Part of OceanSITES
Line W/ Station W  N Atlantic 39°N; 69°W 2001-pres Link Part of OceanSITES
Cariaco Time-series project     Caribbean-Cariaco basin 10°30N; 64°40W 1995-pres Link Part of Antares
CMEP (Centre for Marine Environmental Prediction)    Lunenberg Bay/N Atlantic 44°20'N; 64°17'W -2008 Link  
Hydrostation "S"  Sargasso Sea 32°10'N; 64°30'W 1954-pres Link  
Bermuda Atlantic Time-Series Sargasso Sea 31°40'N; 64°10'W 1988-pres Link Part of OceanSITES
NTAS (Northwest Tropical Atlantic Station)  NW Tropical Atlantic 15°N, 51°W 2001-pres Link Part of OceanSITES
PIRATA (Pilot Research Moored Array in The Tropical Atlantic)  Tropical Atlantic  19°S-21°N; 8°E-38°W 1977-pres Link Part of OceanSITES
European Station for Time series in the Ocean (ESTOC) NE Atlantic 29°10'N; 15°30'W 1994-pres Link Part of EuroSITES
Central Irminger Sea (CIS) Irminger Sea 59°24'N; 39°24'W 2002-pres Link Part of EuroSITES
Tropical Eastern North Atlantic Time Series Observatory (TENATSO)   Tropical NE Atlantic 17°24'N; 24°30'W 2006-pres Link Part of EuroSITES
Porcupine Abyssal Plain (PAP Site) N Atlantic 49°N; 16°W 1989-pres Link Part of EuroSITES
RAIA  N Atlantic (Portugal, Spain) 37-44°N; 8-10°W   Link  
Monitoring of the Nazare Canyon (MONICAN)  NE Atlantic (Portugal) 39°32'N; 9°12'-9°39'W   Link  
SIMPATICO  NE Atlantic (Portugal) 37-40°N; 8-9°W   Link  
Bóias Ondógrafo    NE Atlantic 41°19'N; 8°59'W   Link  
European Seas 
Irish See Coastal Observatory  Irish Sea 

53-54°30N; 3-5°W 

2001-pres Link  
Western Channel Observatory   Western English Channel

L4: 50°15'N, 4°13'W;

E1: 50°02' N, 4°22'W

1903-pres Link  
Station M   Norwegian Sea 66°N; 2°E 1948-pres Link Part of EuroSITES
Dynamics of Atmospheric Fluxes in the Mediterranean Sea (DYFAMED)   Ligurian Sea/Mediterranean 43°15'N; 7°31'E 1988-pres Link Part of EuroSITES
Helgoland Road Time-Series Station   North Sea 54°11'N; 7°54'E 1962-pres Link  
W1-M3A  Ligurian Sea/Mediterranean 43°47'N; 9°10'E 2004-pres Link Part of EuroSITES
E2-M3A   Adriatic Sea/Mediterranean 41°50'N; 17°45'E 2002-pres Link Part of EuroSITES
Poseidon E1-M3A  Aegean/Cretan Sea 35°40'N; 24°59'E 2007-pres Link Part of EuroSITES
Indian Ocean  
Research moored array for African-asian-australian Monsoon Analysis and prediction (RAMA)   Tropical Indian 15°S-20°N; 55-100°E   Link  
Pacific Ocean 
Maizuru Bay coastal observation NW Pacific (Japan) 135°25E; 35°30N   Link  
Temperature Field Off Tohoku NW Pacific (Japan) 140°E; 40°N   Link  
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