TOPIC 1.
OCEAN-CLIMATE NEXUS
INTRODUCTION – GLOBAL OBSERVATIONS
OF THE INTERIOR OCEAN
The complementary partnership of the Global
Ocean Ship-based Hydrographic Investigations
Program
(GO-SHIP;
https://www.go-ship.org/)
and the Argo Program (https://argo.ucsd.edu) has
been instrumental in providing sustained sub-
surface observations of the global ocean for over
two decades. Since the late twentieth century, new
clues into the ocean’s role in Earth’s climate system
have revealed a need for sustained global ocean
observations (e.g., Gould et al., 2013; Schmitt, 2018)
and stimulated revolutionary technology advances
needed to address the societal mandate. Together,
the international GO-SHIP and Argo Program
responded to this need, providing insight into the
mean state and variability of the physics, biology,
and chemistry of the ocean that led to advance-
ments in fundamental science and monitoring of
the state of Earth's climate.
Historically, ocean temperature profiles have
been obtained from commercial ships, although
the highest quality temperature and salinity
(T/S) profiles came only from research vessels
(Figure 1). Global ocean hydrographic surveys,
including full biogeochemistry and tracers, began in
the mid-1990s under the World Ocean Circulation
Experiment (WOCE) and continue now as GO-SHIP.
T/S and biogeochemistry, as key variables of the
climate system, began to describe variability and
change in patterns of rainfall and evaporation,
absorption of fossil fuel carbon dioxide into the
ocean, and the pace and evolution of global warm-
ing and steric sea level rise (i.e., due to changes
FIGURE 1. Density of profiles collected per 1° square during 10 years of
(a) expendable bathythermograph (XBT), (b) shipboard T/S, and (c) Argo T/S
operations. Data courtesy of World Ocean Database (WOD) 2018 (a and b)
and Argo Program (c)
90°N
60°N
30°N
0°
30°S
60°S
90°S
90°N
60°N
30°N
0°
30°S
60°S
90°S
90°N
60°N
30°N
0°
30°S
60°S
90°S
2 to 5
6 to 20
21 to 50
51 to 100
>100
2 to 5
6 to 20
21 to 50
51 to 100
>100
2 to 5
6 to 20
21 to 50
51 to 100
>100
60°E
120°E
180°
120°W
60°W
0°
WOD18 XBT Data 1991–2000, Density of 619,838 profiles
WOD18 Ocean Station Data 1991–2000, Density of 49,258 T/S profiles
Argo decade 2011–2020, Density of 1,612,816 profiles
The Technological, Scientific, and Sociological Revolution of Global
Subsurface Ocean Observing
By Dean Roemmich*, Lynne Talley*, Nathalie Zilberman*, Emily Osborne*, Kenneth S. Johnson*, Leticia Barbero,
Henry C. Bittig, Nathan Briggs, Andrea J. Fassbender, Gregory C. Johnson, Brian A. King, Elaine McDonagh, Sarah Purkey,
Stephen Riser, Toshio Suga, Yuichiro Takeshita, Virginie Thierry, and Susan Wijffels (*lead authors)