Kelp and shoal of small fish underwater

Top parameters

A model parameter is a value that is included in the model equations. Often, this quantity quantify a physical, biogeochemical or biological feature of the ecosystem (e.g., a mortality rate of phytoplankton, a feeding preference of zooplankton, a sinking rate of particulate matter). Typically, this value is a constant, but it can be assumed to be variable (e.g. stocastically) in the framework assimilation approaches, to represent uncertainties in the model.
A model parameter is a variable that is internal to the model and whose value can be estimated from data. It is important to determine the top parameters for a given model system so as to:

  • Reduce the uncertainty on the model output indicators, by improving the estimates of the parameters; 

  • Generate biogeochemical model ensembles, by perturbing the reference values of the parameters; 

  • Improve understanding of biogeochemical processes and fluxes, by assimilating observations in a state-parameter estimation framework. 

We ranked the biogeochemical parameters of all the Copernicus Marine Service models investigated in SEAMLESS. This was achieved by using the one-dimensional configurations of the models available to users in the SEAMLESS modelling prototype EAT (https://github.com/BoldingBruggeman/eat). The configurations were chosen to simulate different trophic regimes (oligotrophic deep-ocean station “BATS” in the Sargasso Sea and mesotrophic coastal station “L4” in the English Channel) in contrasting physical conditions (mixed and stratified water column). A Monte-Carlo based sensitivity of the parameters was then run to rank the most important (see the details in the deliverable D3.2 of SEAMLESS: doi: 10.5281/zenodo.6580236). The following tables list the 10 most important parameters for each biogeochemical model. 

PISCES (Pelagic Interactions Scheme for Carbon and Ecosystem Studies; doi.org/10.5194/gmd-8-2465-2015) 

PISCES 

Rank 

Notation 

Description 

Score  

Group 

dom_rem/xremik 

DOM remineralization rate 

100% 

[10] 

dom_rem/xkdoc 

DOC half-saturation constant in limiting bacterial DOM degradation activity (Aumont et al, Eq 34) 

99% 

[12]  

Optics/parlux 

PAR : SWR ratio 

93% 

[6] 

zoo/xprefn    

Microzooplankton preference for nanophyto 

91% 

[17] 

Dia/mumax0 

Diatoms Max Growth 

90% 

[1] 

Phy/logbp 

Nanophyto temperature sensitivity for growth 

88% 

[5] 

zoo/grazrat    

MicroZoo maximum grazing rate 

85% 

[13] 

phy/mumax0   

Nanophyto Max Growth 

83% 

[1] 

dia/logbp 

Diatoms Temperature sensitivity for growth 

81% 

[5] 

10 

phy/padlopers  

Nanophyto P-I slope 

67% 

[1] 


 

ECOSMO II (ECOSystem Model; doi.org/10.1016/j.jmarsys.2013.03.008)  

ECOSMO

Rank 

Notation 

Description 

Score  

Group 

g2 

E-folding depth of visible fraction (m) 

100% 

[6] 

muPs 

Maximum growth rate of small Phytoplankton 

83%  

[1] 

mPs 

Small Phytoplankton mortality rate 

69%  

[3] 

non-visible fraction of shortwave radiation 

66%  

[6] 

GrZsP 

Grazing rate of small Zooplankton on Phytoplankton 

64%  

[13] 

gammaZsp 

Small Zooplankton assimilation efficiency on Phytoplankton 

52%  

[13] 

reminD 

Detritus remineralization rate 

42%  

[10,18] 

alfaPs 

Initial slope of P-I curve for small Phytoplankton 

41%  

[1] 

rPO4 

PO4 half saturation 

38%  

[10] 

10 

Rg 

Half saturation rate for Zooplankton 

37% 

[13,16] 


ERGOM (Ecological Regional Ocean Model; doi.org/10.1016/S0924-7963(00)00030-0

ERGOM 

Rank 

Notation 

Description 

Score  

Group 

rp0 

Diatoms uptake rate 

100% 

[17] 

q10_rec 

sediment recycling q10 rule factor 

98% 

[5] 

rfr 

Redfield ratio P/N 

79% 

[1] 

imin_di 

minimal optimal light radiation, diatoms 

66% 

[21] 

graz 

Zooplankton grazing rate 

55% 

[13] 

deltao 

Phytoplankton mortality rate (pl -> dd) 

49% 

[10] 

dn 

Detritus mineralization rate (dd -> aa) 

45% 

[17 or 11] 

rf0 

Flagellates uptake rate 

44% 

[12] 

iv 

Ivlev constant, quadratic 

42% 

[11] 

10 

zcl1 

Zooplankton closure parameter 

40% 

[14] 

 

BFM (Biogeochemical Flux Model; doi.org/10.1016/j.jmarsys.2006.03.006

BFM 

Rank 

Notation 

Description 

Score  

Group 

light/EPS0r 

Background shortwave attenuation 

100% 

[21] 

light/pEIR_eow 

Photosynthetically active fraction of shortwave radiation 

57% 

[6] 

B1/p_pu_ra 

Activity respiration fraction, bacteria 

55% 

[9] 

Z5/p_pu 

 Assimilation efficiency, microzooplankton 

44% 

[13] 

P3/p_q10 

Q10 coefficient, picophytoplankton 

40% 

[5] 

Z4/p_sds 

Exponent of density-dependent mortality, omnivorous mesozooplankton 

38% 

[14] 

P3/p_qlcPPY 

Reference Chla:C quotum, picophytoplankton 

35% 

[1] 

P3/p_qplc 

Minimum phosphorus to carbon ratio, picophytoplankton 

33% 

[4] 

P3/p_temp 

Cut-off threshold for temperature factor, picophytoplankton 

32% 

[5] 

10 

P2/p_qlcPPY 

Reference Chla:C quotum, nanophytoplankton 

32% 

[1] 

 

ERSEM (European Regional Seas Ecosystem Model; doi.org/10.5194/gmd-9-1293-2016, 2016) 

ERSEM 

Rank 

Notation 

Description 

Score  

Group 

light/PEIR_eow, 

photosynthetically active fraction of shortwave radiation, 

100% 

[6] 

B1/pu 

efficiency at high oxygen levels (bacteria) 

92% 

[9] 

B1/sR1 

maximum turn-over rate of DOM 

83% 

[12] 

light/a0w 

absorption coefficient of clear water 

74% 

[21] 

B1/rR2 

fraction of semi-labile DOC available to bacteria 

69% 

[12] 

P2/xqcn 

threshold for nitrogen limitation (relative to Redfield ratio) in nanophytoplankton 

61% 

[20] 

P1/xqn 

maximum nitrogen to carbon ratio (relative to Redfield ratio) for diatoms 

58% 

[20] 

P1/xqcn 

threshold for nitrogen limitation (relative to Redfield ratio) in diatoms 

57% 

[20] 

P2/xqn 

maximum nitrogen to carbon ratio (relative to Redfield ratio) for nanophytoplankton 

57% 

[20] 

10 

P1/sum, 

maximum specific productivity at reference temperature for diatoms, 

52% 

[7] 

 


 Assessment of observability/controllability levels of ecosystem indicators in the 5 CMEMS regions. 

Indicator 

ARC 

BAL 

NWES 

MED 

GLO/IBI 

Phenology 

High 

TBD 

High 

Medium 

High 

PP 

n/a 

TBD 

High 

Medium 

Medium 

POC flux 

n/a 

TBD 

High 

Low 

Medium 

PFT 

Medium 

TBD 

Medium 

Medium 

n/a 

Trophic efficiency  

Medium 

TBD 

High 

Low 

Low