Interannual‐to‐Decadal Variations of Particulate Organic Carbon and the Contribution of Phytoplankton in the Tropical Pacific During 1981‐2016: A Model Study

2020 ◽  
Author(s):  
Jun Yu ◽  
Xiujun Wang ◽  
Raghu Murtugudde ◽  
Feng Tian ◽  
Rong‐Hua Zhang
Keyword(s):  
Organic Carbon ◽  
Particulate Organic Carbon ◽  
Tropical Pacific ◽  
Model Study ◽  
Decadal Variations ◽  
The Tropical Pacific

scholarly journals Variability in efficiency of particulate organic carbon export: A model study

2015 ◽  
Vol 29 (1) ◽  
pp. 33-45 ◽  
Author(s):  
Stephanie A. Henson ◽  
Andrew Yool ◽  
Richard Sanders
Keyword(s):  
Organic Carbon ◽  
Particulate Organic Carbon ◽  
Carbon Export ◽  
Model Study

scholarly journals Impacts of Atlantic Multidecadal Variability on the Tropical Pacific: a multi-model study

2021 ◽  
Author(s):  
Yohan Ruprich-Robert ◽  
Keyword(s):  
Tropical Pacific ◽  
Equatorial Pacific ◽  
Tropical Atlantic ◽  
Atlantic Multidecadal Variability ◽  
Multidecadal Variability ◽  
Upper Troposphere ◽  
Model Study ◽  
Model Set ◽  
Static Energy ◽  
The Tropical Pacific

<p>The Atlantic Multidecadal Variability (AMV) has been linked to the observed slowdown of global warming over 1998-2012 through its impact on the tropical Pacific. Given the global importance of tropical Pacific variability, better understanding this Atlantic-Pacific teleconnection is key for improving climate predictions, but the robustness and strength of this link is uncertain. Analysing a multi-model set of sensitivity experiments, we find that models differ by a factor 10 in simulating the amplitude of the Equatorial Pacific cooling response to observed AMV warming. The inter-model spread is mainly driven by different amounts of moist static energy injection from the tropical Atlantic surface into the upper troposphere. We reduce this inter-model uncertainty by analytically correcting models for their mean precipitation biases and we quantify that, following an observed 0.26ºC AMV warming, the equatorial Pacific cools by 0.16ºC with an inter-model standard deviation of 0.03ºC.</p>

scholarly journals Impacts of Atlantic multidecadal variability on the tropical Pacific: a multi-model study

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Yohan Ruprich-Robert ◽  
Eduardo Moreno-Chamarro ◽  
Xavier Levine ◽  
Alessio Bellucci ◽  
Christophe Cassou ◽  
...  
Keyword(s):  
Tropical Pacific ◽  
Equatorial Pacific ◽  
Tropical Atlantic ◽  
Atlantic Multidecadal Variability ◽  
Multidecadal Variability ◽  
Upper Troposphere ◽  
Model Study ◽  
Model Set ◽  
Static Energy ◽  
The Tropical Pacific

AbstractAtlantic multidecadal variability (AMV) has been linked to the observed slowdown of global warming over 1998–2012 through its impact on the tropical Pacific. Given the global importance of tropical Pacific variability, better understanding this Atlantic–Pacific teleconnection is key for improving climate predictions, but the robustness and strength of this link are uncertain. Analyzing a multi-model set of sensitivity experiments, we find that models differ by a factor of 10 in simulating the amplitude of the Equatorial Pacific cooling response to observed AMV warming. The inter-model spread is mainly driven by different amounts of moist static energy injection from the tropical Atlantic surface into the upper troposphere. We reduce this inter-model uncertainty by analytically correcting models for their mean precipitation biases and we quantify that, following an observed 0.26 °C AMV warming, the equatorial Pacific cools by 0.11 °C with an inter-model standard deviation of 0.03 °C.

The Carbon:²³⁴Thorium ratios of sinking particles in the California Current Ecosystem 2: Examination of a thorium sorption, desorption, and particle transport model

2019 ◽  
Author(s):  
Michael Stukel ◽  
Thomas Kelly
Keyword(s):  
Organic Carbon ◽  
Water Column ◽  
Particulate Organic Carbon ◽  
Transport Model ◽  
California Current ◽  
In Situ Measurements ◽  
Power Law Distribution ◽  
Sinking Particles ◽  
Organic Carbon Concentration

Thorium-234 (234Th) is a powerful tracer of particle dynamics and the biological pump in the surface ocean; however, variability in carbon:thorium ratios of sinking particles adds substantial uncertainty to estimates of organic carbon export. We coupled a mechanistic thorium sorption and desorption model to a one-dimensional particle sinking model that uses realistic particle settling velocity spectra. The model generates estimates of 238U-234Th disequilibrium, particulate organic carbon concentration, and the C:234Th ratio of sinking particles, which are then compared to in situ measurements from quasi-Lagrangian studies conducted on six cruises in the California Current Ecosystem. Broad patterns observed in in situ measurements, including decreasing C:234Th ratios with depth and a strong correlation between sinking C:234Th and the ratio of vertically-integrated particulate organic carbon (POC) to vertically-integrated total water column 234Th, were accurately recovered by models assuming either a power law distribution of sinking speeds or a double log normal distribution of sinking speeds. Simulations suggested that the observed decrease in C:234Th with depth may be driven by preferential remineralization of carbon by particle-attached microbes. However, an alternate model structure featuring complete consumption and/or disaggregation of particles by mesozooplankton (e.g. no preferential remineralization of carbon) was also able to simulate decreasing C:234Th with depth (although the decrease was weaker), driven by 234Th adsorption onto slowly sinking particles. Model results also suggest that during bloom decays C:234Th ratios of sinking particles should be higher than expected (based on contemporaneous water column POC), because high settling velocities minimize carbon remineralization during sinking.

Growing Coconut Palms in the Pacific Islands: Colliding Knowledge and Values

2020 ◽  
Author(s):  
Judith A. Bennett
Keyword(s):  
Pacific Islands ◽  
Social Values ◽  
Coconut Oil ◽  
Tropical Pacific ◽  
Experiential Knowledge ◽  
The West ◽  
Passive Resistance ◽  
The People ◽  
The Pacific ◽  
The Tropical Pacific

Coconuts provided commodities for the West in the form of coconut oil and copra. Once colonial governments established control of the tropical Pacific Islands, they needed revenue so urged European settlers to establish coconut plantations. For some decades most copra came from Indigenous growers. Administrations constantly urged the people to thin old groves and plant new ones like plantations, in grid patterns, regularly spaced and weeded. Local growers were instructed to collect all fallen coconuts for copra from their groves. For half a century, the administrations’ requirements met with Indigenous passive resistance. This paper examines the underlying reasons for this, elucidating Indigenous ecological and social values, based on experiential knowledge, knowledge that clashed with Western scientific values.

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