Inter-annual predictability of net primary productivity in the central equatorial Pacific

2020 ◽  
Author(s):  
Sebastian Brune ◽  
Maria Caballero Espejo ◽  
Hongmei Li ◽  
Tatiana Ilyina ◽  
Johanna Baehr
Keyword(s):  
Primary Production ◽  
Primary Productivity ◽  
Time Scale ◽  
Rossby Waves ◽  
Net Primary Productivity ◽  
Tropical Pacific ◽  
Equatorial Pacific ◽  
Prediction Skill ◽  
Central Equatorial Pacific ◽  
Equatorial Rossby Waves

<p>We analyse central equatorial Pacific inter-annual prediction skill of sea surface temperature (SST) and net primary productivity (NPP) using initialized retrospective forecasts with the Max Planck Institute Earth system model over the time period 1998-2014. We find significant NPP predictability for up to 5 lead years, which is far beyond the SST predictability of less than 1 year in this area. While El-Nino-Southern-Oscillation (ENSO) limits SST predictability, we find the origin of the high NPP prediction skill to be in the tropical upwelling zones of the eastern Pacific, i.e., the Peru-Chile current system offshore South America. Off-equatorial Rossby waves are initiated off the coast of Chile and travel towards the central tropical Pacific on a time scale of 4 to 5 years. On their arrival, the Rossby waves modify the depth of the nutricline, which is fundamental to the availability of nutrients in the euphotic layer in the central tropical Pacific.</p><p>We further demonstrate that the seasonal upwelling in the central equatorial Pacific, which is mainly driven by ENSO, transports nutrients, i.e. nitrate and phosphate, from below the nutricline into the euphotic zone, effectively transferring the Rossby wave signal from depth to the near-surface ocean. A shallower than normal nutricline leads to larger primary production, and vice versa, a deeper than normal nutricline to smaller primary production. The Rossby waves also modulate the SST, however, these changes are damped on the daily to weekly time scale due to surface heat fluxes at the atmosphere-ocean boundary. Therefore, the off-equatorial Rossby waves maintain the high predictability of NPP but not the SST. We conclude that NPP predictions in the central equatorial Pacific benefit from the memory contained in properly simulated off-equatorial Rossby waves.</p>

scholarly journals Oceanic Rossby waves drive inter-annual predictability of net primary production in the central tropical Pacific

2021 ◽  
Author(s):  
Sebastian Brune ◽  
Maria Esther Caballero Espejo ◽  
David Marcolino Nielsen ◽  
Hongmei Li ◽  
Tatiana Ilyina ◽  
...  
Keyword(s):  
Primary Production ◽  
Primary Productivity ◽  
Rossby Waves ◽  
Net Primary Productivity ◽  
Net Primary Production ◽  
Tropical Pacific ◽  
Prediction System ◽  
Decadal Prediction ◽  
Near Surface ◽  
Equatorial Rossby Waves

Abstract In the Pacific Ocean, off-equatorial Rossby waves, initiated by atmosphere-ocean interaction, modulate the inter-annual variability of the thermocline. In this study, we explore the resulting potential gain in predictability of central tropical Pacific primary production, which in this region strongly depends on the supply of macronutrients from below the thermocline. We use a decadal prediction system based on the Max Planck Institute Earth system model (MPI-ESM) to demonstrate that for the time period 1998-2014 properly initialized Rossby waves explain an increase in predictability of net primary productivity in the off-equatorial central tropical Pacific. We show that, for up to 5 years in advance, predictability of net primary productivity derived from the decadal prediction system is significantly larger than that derived from persistence alone, or an uninitialized historical simulation. The predicted signal can be explained by the following mechanism: off-equatorial Rossby waves are initiated in the eastern Pacific and travel towards the central tropical Pacific on a time scale of 2 to 6 years. On their arrival the Rossby waves modify the depths of both thermocline and nutricline, which is fundamental to the availability of nutrients in the euphotic layer. Local upwelling transports nutrients from below the nutricline into the euphotic zone, effectively transferring the Rossby wave signal to the near-surface ocean. While we show that skillful prediction of central off-equatorial tropical Pacific net primary productivity is possible, we open the door for establishing predictive systems for food web and ecosystem services in that region.

scholarly journals Upper-Ocean Salinity Variability in the Tropical Pacific: Case Study for Quasi-Decadal Shift during the 2000s Using TRITON Buoys and Argo Floats

2013 ◽  
Vol 26 (20) ◽  
pp. 8126-8138 ◽  
Author(s):  
Takuya Hasegawa ◽  
Kentaro Ando ◽  
Iwao Ueki ◽  
Keisuke Mizuno ◽  
Shigeki Hosoda
Keyword(s):  
Tropical Pacific ◽  
Equatorial Pacific ◽  
Sea Surface ◽  
Upper Ocean ◽  
Salinity Variability ◽  
Ocean Salinity ◽  
Central Equatorial Pacific ◽  
Western Equatorial Pacific ◽  
Sea Surface Temperature Anomalies ◽  
The Tropical Pacific

Abstract Upper-ocean salinity variation in the tropical Pacific is investigated during the 2000s, when Triangle Trans-Ocean Buoy Network (TRITON) buoys and Argo floats were deployed and more salinity data were observed than in previous periods. This study focuses on upper-ocean salinity variability during the warming period of El Niño–Southern Oscillation (ENSO)-like quasi-decadal (QD)-scale sea surface temperature anomalies over the central equatorial Pacific (January 2002–December 2005; hereafter “warm QD phase”). It is shown that strong negative salinity anomalies occur in the western tropical Pacific and the off-equatorial Pacific in the upper ocean at depths less than 80 m, showing a horseshoe-like pattern centered at the western tropical Pacific during the warm QD phase. TRITON mooring buoy data in the western equatorial Pacific show that low-salinity and high-temperature water could be transported eastward from the western equatorial Pacific to the central equatorial Pacific during the warm QD phase. Similar patterns, but with the opposite sign of salinity anomalies, appear in the cold QD phase during January 2007–December 2009 with negative sea surface temperature anomalies over the central equatorial Pacific. It is suggested that effects from zonal salinity advection and precipitation could contribute to the generation of the salinity variations in the western equatorial Pacific for QD phases during the 2000s. On the other hand, the contribution of meridional salinity advection is much less than that of zonal salinity advection. In addition, El Niño Modoki and La Niña events could affect salinity changes for warm and cold QD phases via interannual-scale zonal salinity advection variations in the western equatorial Pacific during the 2000s.

scholarly journals Primary productivity in the central equatorial Pacific (3°S 130°W) during GasEx-2001

2004 ◽  
Vol 109 (C8) ◽  
pp. n/a-n/a ◽  
Author(s):  
Peter G. Strutton ◽  
Francisco P. Chavez ◽  
Richard C. Dugdale ◽  
Victoria Hogue
Keyword(s):  
Primary Productivity ◽  
Equatorial Pacific ◽  
Central Equatorial Pacific

scholarly journals Iron and grazing constraints on primary production in the central equatorial Pacific: An EqPac synthesis

1997 ◽  
Vol 42 (3) ◽  
pp. 405-418 ◽  
Author(s):  
Michael R. Landry ◽  
Richard T. Barber ◽  
Robert R. Bidigare ◽  
Fei Chai ◽  
Kenneth H. Coale ◽  
...  
Keyword(s):  
Primary Production ◽  
Equatorial Pacific ◽  
Central Equatorial Pacific

scholarly journals Evaluation of the eastern equatorial Pacific SST seasonal cycle in CMIP5 models

2014 ◽  
Vol 11 (2) ◽  
pp. 1129-1147
Author(s):  
Z. Song ◽  
H. Liu ◽  
L. Zhang ◽  
F. Qiao ◽  
C. Wang
Keyword(s):  
Annual Cycle ◽  
Seasonal Cycle ◽  
General Circulation ◽  
General Circulation Models ◽  
Tropical Pacific ◽  
Equatorial Pacific ◽  
Eastern Coast ◽  
Cmip5 Models ◽  
Eastern Equatorial Pacific ◽  
Central Equatorial Pacific

Abstract. The annual cycle of sea surface temperature (SST) in the eastern equatorial Pacific (EEP) with the largest amplitude in the tropical oceans is poorly represented in the coupled general circulation models (CGCMs) of the Coupled Model Intercomparison Project phase 3 (CMIP3). In this study, 18 models from CMIP5 projects are evaluated in simulating the annual cycle in the EEP. Fourteen models are able to simulate the annual cycle, and four still show erroneous information in the simulation, which suggests that the performances of CGCMs have been improved. The results of multi-model ensemble (MME) mean show that CMIP5 CGCMs can capture the annual cycle signal in the EEP with correlation coefficients up to 0.9. For amplitude simulations, EEP region 1 (EP1) near the eastern coast shows weaker results than observations due to the large warm SST bias from the southeastern tropical Pacific in the boreal autumn. In EEP region 2 (EP2) near the central equatorial Pacific, the simulated amplitudes are nearly the same as the observations because of the presence of a quasi-constant cold bias associated with poor cold tongue climatology simulation in the CGCMs. To improve CGCMs in the simulation of a realistic SST seasonal cycle, local and remote climatology SST biases that exist in both CMIP3 and CMIP5 CGCMs must be resolved at least for the simulation in the central equatorial Pacific and the southeastern tropical Pacific.

scholarly journals A Pacific Centennial Oscillation Predicted by Coupled GCMs*

2012 ◽  
Vol 25 (17) ◽  
pp. 5943-5961 ◽  
Author(s):  
Kristopher B. Karnauskas ◽  
Jason E. Smerdon ◽  
Richard Seager ◽  
Jesús Fidel González-Rouco
Keyword(s):  
Time Scale ◽  
General Circulation ◽  
Southern Oscillation ◽  
Heat Content ◽  
General Circulation Models ◽  
Wave Pattern ◽  
Tropical Pacific ◽  
Equatorial Pacific ◽  
Centennial Time Scale ◽  
The Tropical Pacific

Abstract Internal climate variability at the centennial time scale is investigated using long control integrations from three state-of-the-art global coupled general circulation models. In the absence of external forcing, all three models produce centennial variability in the mean zonal sea surface temperature (SST) and sea level pressure (SLP) gradients in the equatorial Pacific with counterparts in the extratropics. The centennial pattern in the tropical Pacific is dissimilar to that of the interannual El Niño–Southern Oscillation (ENSO), in that the most prominent expression in temperature is found beneath the surface of the western Pacific warm pool. Some global repercussions nevertheless are analogous, such as a hemispherically symmetric atmospheric wave pattern of alternating highs and lows. Centennial variability in western equatorial Pacific SST is a result of the strong asymmetry of interannual ocean heat content anomalies, while the eastern equatorial Pacific exhibits a lagged, Bjerknes-like response to temperature and convection in the west. The extratropical counterpart is shown to be a flux-driven response to the hemispherically symmetric circulation anomalies emanating from the tropical Pacific. Significant centennial-length trends in the zonal SST and SLP gradients rivaling those estimated from observations and model simulations forced with increasing CO2 appear to be inherent features of the internal climate dynamics simulated by all three models. Unforced variability and trends on the centennial time scale therefore need to be addressed in estimated uncertainties, beyond more traditional signal-to-noise estimates that do not account for natural variability on the centennial time scale.

Interannual and Interdecadal Variabilities of Spring Rainfall over Northeast China and Their Associated Sea Surface Temperature Anomaly Forcings

2020 ◽  
Vol 33 (4) ◽  
pp. 1423-1435 ◽  
Author(s):  
Rui Lu ◽  
Zhiwei Zhu ◽  
Tim Li ◽  
Haiyang Zhang
Keyword(s):  
Rossby Wave ◽  
Time Scale ◽  
Northeast China ◽  
Numerical Experiments ◽  
Warm Pool ◽  
Equatorial Pacific ◽  
Convective Heating ◽  
Maritime Continent ◽  
Northeastern Asia ◽  
Central Equatorial Pacific

AbstractAn empirical orthogonal function (EOF) analysis was conducted for spring precipitation gauge data over northeast China (NEC). The first EOF mode is characterized by a homogenous rainfall pattern throughout NEC. The corresponding principal component has both significant interannual and interdecadal variations. This leading mode explains a large portion of the total NEC spring rainfall (NECSR) variances and is statistically independent from other higher modes. The physical processes responsible for the interannual and interdecadal variabilities were investigated via observational diagnoses and numerical experiments. On the interannual time scale, NECSR is mainly affected by the SST anomalies (SSTAs) in the northern tropical Atlantic Ocean. When the SSTAs are positive, the subsequently induced positive precipitation and convection can stimulate two quasi-barotropic Rossby wave trains over the mid- to high latitudes. A cyclonic anomaly center of the Rossby wave train appears over northeastern Asia, leading to a positive rainfall anomaly in the region. On the interdecadal time scale, NECSR is mainly influenced by the SSTAs over the warm-pool region. Positive SSTAs in the warm-pool region result in enhanced convection (ascending motion) around the Maritime Continent and suppressed convection (descending motion) over the central equatorial Pacific Ocean. This zonal dipole convection pattern stimulates a quasi-barotropic circulation pattern with an anticyclonic anomaly over the Tibetan Plateau and a cyclonic anomaly over northeastern Asia. The cyclonic anomaly over northeastern Asia enhances the NECSR. Numerical experiments further suggested that the convective heating anomaly over the Maritime Continent, rather than cooling over the central equatorial Pacific, plays a more essential role in driving the interdecadal rainfall variability of NECSR.

scholarly journals Variation in Primary Production in Relation to Physico-Chemical Parameters of Kadwai Reservoir, Ratnagiri, Maharashtra, India.

2016 ◽  
Vol 11 (1) ◽  
pp. 228-232 ◽  
Author(s):  
Rahul Rathod ◽  
Balasaheb R. Chavan ◽  
Raghuvendra Pai
Keyword(s):  
Primary Production ◽  
Primary Productivity ◽  
Net Primary Productivity ◽  
Monsoon Season ◽  
Total Alkalinity ◽  
Organic Load ◽  
Total Hardness ◽  
Post Monsoon ◽  
Physiochemical Parameters ◽  
Post Monsoon Season

The present study has been carried out to study the status of primary productivity in relation to physiochemical parameters of the Kadwai reservoir of Ratnagiri district, Maharashtra. The primary productivity was determined by estimating gross and net primary productivity. The experiment was conducted during the monsoon and post monsoon seasons from 1st June to 30th Nov 2015 to know the effect of organic run off on primary production of Kadwai reservoir. The physiochemical parameters such as temperature, pH, dissolved oxygen, total hardness, total alkalinity and transparency ranged from 27oC-30.5oC, 7.5-8.6, 3.2-7.0 mg/l, 46-75 mg/l, 56-95 mg/l, and 118-130 cm, respectively. The gross primary productivity (GPP) during monsoon was 0.07-0.11 gC/m3/hr in June, July and August 2015, respectively, which was very low, whereas GPP were increased during post monsoon season. The values were recorded as 0.12-0.48 gC/m3/hr in the months of September, October, and November 2015, respectively. The results indicated that during monsoon season, organic load is coming along with water in to the reservoir, but phytoplankton growth is minimum due to the heavy rain and flushing rate were high from the downstream of the reservoir. During post monsoon, primary productivity was increased. The results indicate that Kadwai reservoir is more productive during post monsoon season suitable for stocking fish seed.

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