scholarly journals Modeling Coral Bleaching Mitigation Potential of Water Vertical Translocation – An Analogue to Geoengineered Artificial Upwelling

2020 ◽  
Vol 7 ◽  
Author(s):  
Ellias Y. Feng ◽  
Yvonne Sawall ◽  
Marlene Wall ◽  
Mario Lebrato ◽  
Yao Fu
Keyword(s):  
Coral Reefs ◽  
Coral Bleaching ◽  
Deep Ocean ◽  
Sea Surface ◽  
System Model ◽  
Earth System ◽  
Mitigation Potential ◽  
Management Procedure ◽  
Location Depth ◽  
Emissions Scenario

Artificial upwelling (AU) is a novel geoengineering technology that brings seawater from the deep ocean to the surface. Within the context of global warming, AU techniques are proposed to reduce sea surface temperature at times of thermal stress around coral reefs. A computationally fast but coarse 3D Earth System model (3.6° longitude × 1.8° latitude) was used to investigate the environmental impacts of hypothetically implemented AU strategies in the Great Barrier Reef, South China Sea, and Hawaiian regions. While omitting the discussion on sub-grid hydrology, we simulated in our model a water translocation from either 130 or 550 m depth to sea surface at rates of 1 or 50 m3 s–1 as analogs to AU implementation. Under the Representative Concentration Pathway 8.5 emissions scenario from year 2020 on, the model predicted a prevention of coral bleaching until the year 2099 when AU was implemented, except under the least intense AU scenario (water from 130 m depth at 1 m3 s–1). Yet, intense AU implementation (water from 550 m depth at 50 m3 s–1) will likely have adverse effects on coral reefs by overcooling the surface water, altering salinity, decreasing calcium carbonate saturation, and considerably increasing nutrient levels. Our result suggests that if we utilize AU for mitigating coral bleaching during heat stress, AU implementation needs to be carefully designed with respect to AU’s location, depth, intensity and duration so that undesirable environmental effects are minimized. Following a proper installation and management procedure, however, AU has the potential to decelerate destructive bleaching events and buy corals more time to adjust to climate change.

scholarly journals Can an Earth System Model simulate better climate change at mid-Holocene than an AOGCM? A comparison study of MIROC-ESM and MIROC3

2013 ◽  
Vol 9 (4) ◽  
pp. 1519-1542 ◽  
Author(s):  
R. Ohgaito ◽  
T. Sueyoshi ◽  
A. Abe-Ouchi ◽  
T. Hajima ◽  
S. Watanabe ◽  
...  
Keyword(s):  
Climate Change ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Earth System Model ◽  
Sea Surface ◽  
System Model ◽  
Earth System ◽  
Intercomparison Project ◽  
The Difference ◽  
Precipitation Enhancement

Abstract. The importance of evaluating models through paleoclimate simulations is becoming more recognized in efforts to improve climate projection. To evaluate an integrated Earth System Model, MIROC-ESM, we performed simulations in time-slice experiments for the mid-Holocene (6000 yr before present, 6 ka) and preindustrial (1850 AD, 0 ka) periods under the protocol of the Coupled Model Intercomparison Project 5/Paleoclimate Modelling Intercomparison Project 3. We first give an overview of the simulated global climates by comparing with simulations using a previous version of the MIROC model (MIROC3), which is an atmosphere–ocean coupled general circulation model. We then comprehensively discuss various aspects of climate change with 6 ka forcing and how the differences in the models can affect the results. We also discuss the representation of the precipitation enhancement at 6 ka over northern Africa. The precipitation enhancement at 6 ka over northern Africa according to MIROC-ESM does not differ greatly from that obtained with MIROC3, which means that newly developed components such as dynamic vegetation and improvements in the atmospheric processes do not have significant impacts on the representation of the 6 ka monsoon change suggested by proxy records. Although there is no drastic difference between the African monsoon representations of the two models, there are small but significant differences in the precipitation enhancement over the Sahara in early summer, which can be related to the representation of the sea surface temperature rather than the vegetation coupling in MIROC-ESM. Because the oceanic parts of the two models are identical, the difference in the sea surface temperature change is ultimately attributed to the difference in the atmospheric and/or land modules, and possibly the difference in the representation of low-level clouds.

Decadal Prediction of Marine Heatwaves in MPI-ESM

2021 ◽  
Author(s):  
Laura Hövel ◽  
Sebastian Brune ◽  
Johanna Baehr
Keyword(s):  
North Atlantic ◽  
Regional Differences ◽  
Correlation Coefficients ◽  
Sea Surface ◽  
System Model ◽  
Climate Projections ◽  
Earth System ◽  
Max Planck ◽  
Circulation Patterns ◽  
Decadal Predictability

<p>Marine Heatwaves (MHWs) are Sea Surface Temperature (SST) extremes that can have devastating impacts on marine ecosystems but can also impact circulation patterns in the ocean and the atmosphere. The variability of MHWs has been studied in historical observations and longterm climate projections, but predictability has only been analyzed on seasonal timescales. Here, we we present the first attempt to study the decadal predictability of MHW days per year in an ensemble of decadal hindcasts based on the Max Planck Institute Earth System Model (MPI-ESM-LR).</p><p>Our results show that there are strong regional differences in prediction skill. While many regions show little to no skill, we find in the Subpolar North Atlantic correlation coefficients up to 0.7 for MHW days up to lead year 8. We demonstrate that these correlations mainly arise from correctly predicting the absence of MHWs in individual years. MHW days per year might be successfully predicted by only using yearly mean SST as a proxy, which also demonstrates that in the Subpolar North Atlantic, any increase in SST is accompanied by more MHWs and vice versa.</p>

scholarly journals North Atlantic Storm-Track Sensitivity to Projected Sea Surface Temperature: Local versus Remote Influences

2016 ◽  
Vol 29 (19) ◽  
pp. 6973-6991 ◽  
Author(s):  
Laura M. Ciasto ◽  
Camille Li ◽  
Justin J. Wettstein ◽  
Nils Gunnar Kvamstø
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
North Atlantic ◽  
Storm Track ◽  
Sea Surface ◽  
System Model ◽  
Earth System ◽  
Model Version ◽  
The North ◽  
The North Atlantic

Abstract This study investigates the sensitivity of the North Atlantic storm track to future changes in local and global sea surface temperature (SST) and highlights the role of SST changes remote to the North Atlantic. Results are based on three related coupled climate models: the Community Climate System Model, version 4 (CCSM4), the Community Earth System Model, version 1 (Community Atmosphere Model, version 5) [CESM1(CAM5)], and the Norwegian Earth System Model, version 1 (intermediate resolution) (NorESM1-M). Analysis reveals noticeable intermodel differences in projected storm-track changes from the coupled simulations [i.e., the difference in 200-hPa eddy activity between the representative concentration pathway 8.5 (RCP8.5) and historical scenarios]. In the CCSM4 coupled simulations, the North Atlantic storm track undergoes a poleward shift and eastward extension. In CESM1(CAM5), the storm-track change is dominated by an intensification and eastward extension. In NorESM1-M, the storm-track change is characterized by a weaker intensification and slight eastward extension. Atmospheric experiments driven only by projected local (North Atlantic) SST changes from the coupled models fail to reproduce the magnitude and structure of the projected changes in eddy activity aloft and zonal wind from the coupled simulations. Atmospheric experiments driven by global SST and sea ice changes do, however, reproduce the eastward extension. Additional experiments suggest that increasing greenhouse gas (GHG) concentrations do not directly influence storm-track changes in the coupled simulations, although they do through GHG-induced changes in SST. The eastward extension of the North Atlantic storm track is hypothesized to be linked to western Pacific SST changes that influence tropically forced Rossby wave trains, but further studies are needed to isolate this mechanism from other dynamical adjustments to global warming.

scholarly journals Evaluation and climate sensitivity of the PlaSim v.17 Earth System Model coupled with ocean model components of different complexity

2020 ◽  
Author(s):  
Michela Angeloni ◽  
Elisa Palazzi ◽  
Jost von Hardenberg
Keyword(s):  
Sea Ice ◽  
Heat Transport ◽  
Mixed Layer ◽  
Climate Sensitivity ◽  
Ice Cover ◽  
Earth System Model ◽  
Sea Surface ◽  
System Model ◽  
Earth System ◽  
Feedback Mechanisms

Abstract. A set of experiments is performed with coupled atmosphere-ocean configurations of the Planet Simulator, an Earth-system Model of Intermediate Complexity (EMIC), in order to identify under which set of parameters the model output better agrees with observations and reanalyses of the present climate. Different model configurations are explored, in which the atmospheric module of PlaSim is coupled with two possible ocean models, either a simple mixed-layer (ML) ocean with a diffusive transport parameterization or a more complex dynamical Large-Scale Geostrophic (LSG) ocean, together with a sea-ice module. In order to achieve a more realistic representation of present-day climate, we performed a preliminary tuning of the oceanic horizontal diffusion coefficient for the ML ocean and of the vertical oceanic diffusion profile when using LSG. Model runs under present-day conditions are compared, in terms of surface air temperature, sea surface temperature, sea ice cover, precipitation, radiation fluxes, ocean circulation, with a reference climate from observations and reanalyses. Our results indicate that, in all configurations, coupled PlaSim configurations are able to reproduce the main characteristics of the climate system, with the exception of the Southern Ocean region in the PlaSim-LSG model, where surface air and sea surface temperatures are warm-biased and sea ice cover is by consequence highly underestimated. The resulting sets of tuned parameters are used to perform a series of model equilibrium climate sensitivity (ECS) experiments, with the aim to identify the main mechanisms contributing to differences between the different configurations and leading to elevated values of ECS. In fact, high resulting global ECS values are found, positioned in the upper range of CMIP5 and recent CMIP6 estimates. Our analysis shows that a significant contribution to ECS is given by the sea-ice feedback mechanisms and by details of the parameterization of meridional oceanic heat transport. In particular, the configurations using a diffusive heat transport in the mixed layer present an important sensitivity in terms of radiative forcing to changes in sea-ice cover, leading to an important contribution of sea-ice feedback mechanisms to ECS.

Factors affecting the cycling of dimethylsulfide and dimethylsulfoniopropionate in coral reef waters of the Great Barrier Reef

2007 ◽  
Vol 4 (5) ◽  
pp. 310 ◽  
Author(s):  
Graham Jones ◽  
Mark Curran ◽  
Andrew Broadbent ◽  
Stacey King ◽  
Esther Fischer ◽  
...  
Keyword(s):  
Coral Reefs ◽  
Great Barrier Reef ◽  
Coral Bleaching ◽  
Time Of Day ◽  
Sea Surface ◽  
Sea Surface Temperatures ◽  
Barrier Reef ◽  
Magnetic Island ◽  
Surface Temperatures ◽  
Acropora Formosa

Environmental context. Levels of atmospheric dimethylsulfide (DMS) and its oxidation products are reputed to affect the microphysics of clouds and the amount of incoming solar radiation to the ocean. Studies of DMS and its precursor compound dimethylsulfoniopropionate (DMSP) at two inshore fringing coral reefs in the Great Barrier Reef highlight pronounced seasonal, diurnal and tidal variation of these compounds, with dissolved DMS and DMSP significantly correlated with sea surface temperatures (SSTs) up to 30°C. During a coral bleaching episode at one of the reef sites, dissolved DMS concentrations decreased when SSTs exceeded 30°C, a result replicated in chamber experiments with staghorn coral. The results raise interesting questions on the role of these organosulfur substances in corals and whether DMS emissions from coral reefs could have an effect on regional climate in the Great Barrier Reef. Abstract. A study of dissolved dimethylsulfide (DMSw), dissolved and particulate dimethylsulfoniopropionate (DMSPd, DMSPp), and atmospheric dimethylsulfide (DMSa) was carried out at two inshore fringing coral reefs (Orpheus Island and Magnetic Island) in the Great Barrier Reef (GBR) to investigate the variation of these organosulfur substances with season, sea surface temperature, tides, and time of day. Highest concentrations of these organosulfur substances occurred in the summer months at both reefs, with lowest concentrations occurring during winter, suggesting a biological source of these compounds from the reef flats. At the Orpheus Island reef, where more measurements were made, DMSw and DMSPd were significantly correlated with tidal height during the flooding tide over the reef (r = 0.37, P < 0.05; r = 0.58, P < 0.01 respectively), and elevated DMSw and DMSa concentrations generally occurred in the daylight hours, possibly reflecting photosynthetic production of DMSw from the reef flats. Chamber experiments with the staghorn coral Acropora formosa confirmed that corals produce DMSw in the day. DMSw (r = 0.43, P < 0.001) and DMSPd (r = 0.59, P < 0.001) were significantly positively correlated with sea surface temperatures (SST) at the Orpheus Island reef. During severe coral bleaching at the eutrophic Magnetic Island reef in the summer, DMSw concentrations decreased at SSTs greater than 30°C, suggesting that reef production of DMSw decreases during elevated SSTs. This was later confirmed in chamber experiments with Acropora formosa, which showed that when this coral was exposed to temperatures at its bleaching threshold (31°C), decreased production of DMSw occurred. These results suggest that DMS and DMSP in coral zooxanthellae may be functioning as antioxidants, but further experiments are needed to substantiate this.

scholarly journals <sup>231</sup>Pa and <sup>230</sup>Th in the ocean model of the Community Earth System Model (CESM1.3)

2017 ◽  
Vol 10 (12) ◽  
pp. 4723-4742 ◽  
Author(s):  
Sifan Gu ◽  
Zhengyu Liu
Keyword(s):  
Ocean Circulation ◽  
Activity Ratio ◽  
Marine Ecosystem ◽  
Deep Ocean ◽  
Ocean Model ◽  
Earth System Model ◽  
System Model ◽  
Earth System ◽  
Direct Model ◽  
Community Earth System Model

Abstract. The sediment 231Pa ∕ 230Th activity ratio is emerging as an important proxy for deep ocean circulation in the past. In order to allow for a direct model–data comparison and to improve our understanding of the sediment 231Pa ∕ 230Th activity ratio, we implement 231Pa and 230Th in the ocean component of the Community Earth System Model (CESM). In addition to the fully coupled implementation of the scavenging behavior of 231Pa and 230Th with the active marine ecosystem module (particle-coupled: hereafter p-coupled), another form of 231Pa and 230Th have also been implemented with prescribed particle flux fields of the present climate (particle-fixed: hereafter p-fixed). The comparison of the two forms of 231Pa and 230Th helps to isolate the influence of the particle fluxes from that of ocean circulation. Under present-day climate forcing, our model is able to simulate water column 231Pa and 230Th activity and the sediment 231Pa ∕ 230Th activity ratio in good agreement with available observations. In addition, in response to freshwater forcing, the p-coupled and p-fixed sediment 231Pa ∕ 230Th activity ratios behave similarly over large areas of low productivity on long timescales, but can differ substantially in some regions of high productivity and on short timescales, indicating the importance of biological productivity in addition to ocean transport. Therefore, our model provides a potentially powerful tool to help the interpretation of sediment 231Pa ∕ 230Th reconstructions and to improve our understanding of past ocean circulation and climate changes.

scholarly journals Evaluation of NorESM-OC (versions 1 and 1.2), the ocean carbon-cycle stand-alone configuration of the Norwegian Earth System Model (NorESM1)

2016 ◽  
Author(s):  
J. Schwinger ◽  
N. Goris ◽  
J. Tjiputra ◽  
I. Kriest ◽  
M. Bentsen ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
Deep Ocean ◽  
Earth System Model ◽  
System Model ◽  
Earth System ◽  
Atmospheric Forcing ◽  
Ocean Carbon Cycle ◽  
Data Set ◽  
Model Version ◽  
Ocean Carbon

Abstract. Idealised and hindcast simulations performed with the stand-alone ocean carbon-cycle configuration of the Norwegian Earth System Model (NorESM-OC) are described and evaluated. We present simulation results of two different model versions at different grid resolutions and using two different atmospheric forcing data sets. Model version NorESM-OC1 corresponds to the version that is included in the fully coupled model NorESM-ME1, which participated in CMIP5. The main update between NorESM-OC1 and NorESM-OC1.2 is the addition of two new options for the treatment of sinking particles. We find that using a constant sinking speed, which has been the standard in NorESM's ocean carbon cycle module HAMOCC (HAMburg Ocean Carbon Cycle model) does not transport enough particulate organic carbon (POC) into the deep ocean below approximately 2000 m depth. The two newly implemented parameterisations, a particle aggregation scheme with prognostic sinking speed, and a simpler scheme prescribing a linear increase of sinking speed with depth, provide better agreement with observed POC fluxes. Additionally, reduced deep ocean biases of oxygen and remineralised phosphate indicate a better performance of the new parameterisations. For model version 1.2, a re-tuning of the ecosystem parameterisation has been performed, which (i) reduces previously too high primary production in high latitudes, (ii) consequently improves model results for surface nutrients, and (iii) reduces alkalinity and dissolved inorganic carbon biases at low latitudes. We use hindcast simulations with prescribed observed and constant (pre-industrial) atmospheric CO2 concentrations to derive the past and contemporary ocean carbon sink. For the period 1990–1999 we find an average ocean carbon uptake ranging from 2.01 to 2.58 Pg C yr-1 depending on model version, grid resolution and atmospheric forcing data set.

scholarly journals Pre-industrial and mid-Pliocene simulations with NorESM-L

2012 ◽  
Vol 5 (2) ◽  
pp. 523-533 ◽  
Author(s):  
Z. S. Zhang ◽  
K. Nisancioglu ◽  
M. Bentsen ◽  
J. Tjiputra ◽  
I. Bethke ◽  
...  
Keyword(s):  
Surface Air Temperature ◽  
Sea Surface ◽  
System Model ◽  
Test Case ◽  
Earth System ◽  
Warm Climate ◽  
Mean Sea Surface ◽  
Global Mean ◽  
Term Response

Abstract. The mid-Pliocene period (3.3 to 3.0 Ma) is known as a warm climate with atmospheric greenhouse gas levels similar to the present. As the climate at this time was in equilibrium with the greenhouse forcing, it is a valuable test case to better understand the long-term response to high levels of atmospheric greenhouse gases. In this study, we use the low resolution version of the Norwegian Earth System Model (NorESM-L) to simulate the pre-industrial and the mid-Pliocene climate. Comparison of the simulation with observations demonstrates that NorESM-L simulates a realistic pre-industrial climate. The simulated mid-Pliocene global mean surface air temperature is 16.7 °C, which is 3.2 °C warmer than the pre-industrial. The simulated mid-Pliocene global mean sea surface temperature is 19.1 °C, which is 2.0 °C warmer than the pre-industrial. The warming is relatively uniform globally, except for a strong amplification at high latitudes.

scholarly journals PEMETAAN POTENSI PEMUTIHAN KARANG DI PERAIRAN INDONESIA MENGGUNAKAN ANALISIS DATA SUHU PERMUKAAN LAUT

2019 ◽  
Vol 3 ◽  
pp. 65
Author(s):  
Dany Pangestu ◽  
Ratih Suci Ramadhanti ◽  
Ahmad Fadlan
Keyword(s):  
Coral Reefs ◽  
Coral Bleaching ◽  
Economic Value ◽  
Sea Surface ◽  
Northwest Coast ◽  
Northern Coast ◽  
Coral Triangle ◽  
Central Java ◽  
Natural Factors ◽  
Anomaly Analysis

<p class="AbstractEnglish"><strong>Abstract:</strong> Indonesia is the country that contributed the largest coral reefs, about 18% total of the entire the world. Area of coral reef in Indonesia known as the “Coral Triangle”. This ecosystem has high ecology and economic value. The existence of the coral reefs is the main attraction for a tourism destination. However, the function and role of these ecosystems are decreasing due to natural factors and artificial factors. One of the natural factors is due to the influence of global warmings, such as sea surface temperature (SST), causing damage and coral death, known as coral bleaching. The purpose of this study was to identify the potential for coral bleaching in Indonesian waters using SPL anomaly analysis obtained from monthly AVHRR POES in the morning and night. This research used hotspots data (HS) by calculating the average of data anomaly difference with a maximum monthly average data during 10 years (2006 - 2017). The results obtained show that areas that have the potential to become coral bleaching in Indonesian waters are quite varied. In general, it covers the northern coast of Banten, DKI Jakarta, West Java, Central Java, East Java, the northwest coast of Lampung, Pekanbaru, and Riau, the northwest coast of Papua Island, and North Natuna waters. The results also showed that sea surface temperatures in Indonesian waters were quite influential on coral bleaching.</p><p class="KeywordsEngish"><strong>Abstrak:</strong> Indonesia merupakan negara penyumbang terumbu karang terbesar  yaitu 18% dari total dunia. Wilayah terumbu karang di Indonesia dikenal dengan wilayah “<em>Coral Triangle</em>”. Ekosistem ini memiliki nilai ekologis dan ekonomis yang tinggi. Keberadaanya merupakan daya tarik tersendiri untuk dijadikan lokasi wisata. Namun, fungsi dan peranan ekosistem ini menurun akibat faktor alam dan faktor buatan. Salah satu faktor alamnya diakibatkan pengaruh pemanasan global yaitu naiknya suhu permukaan laut (SPL) sehingga menyebabkan kerusakan dan kematian karang atau dikenal sebagai pemutihan karang. Tujuan penelitian ini adalah mengidentifikasi potensi terjadi pemutihan karang di wilayah perairan Indonesia menggunakan analisis anomali SPLyang diperoleh dari POES AVHRR pagi dan malam bulanan. Metode yang diugunakan mencari data hotspot (HS) dengan melakukan  perhitungan rata rata selisih data anomali dengan data rata rata maksimum bulanan selama 10 tahun (2006 - 2017). Hasil yang didapat menunjukkan bahwa wilayah yang berpotensi menjadi pemutihan karang  di perairan Indonesia cukup beravariasi. Secara umum meliputi meliputi pesisir utara dari Provinsi Banten, DKI Jakarta, Jawa Barat, Jawa Tengah, Jawa Timur, pesisir barat laut Lampung ,Pekanbaru dan Riau,  pesisir barat laut dari Pulau Papua, dan perairan Natuna Utara. Hasil penelitian juga menunjukkan bahwa suhu permukaan laut di perairan Indonesia cukup mempengaruhi pemutihan karang<strong>.</strong></p>

scholarly journals GENIE-M: a new and improved GENIE-1 developed in Minnesota

2008 ◽  
Vol 1 (1) ◽  
pp. 1-37 ◽  
Author(s):  
K. Matsumoto ◽  
K. S. Tokos ◽  
A. Price ◽  
S. Cox
Keyword(s):  
Mixed Layer Depth ◽  
Single Layer ◽  
Deep Ocean ◽  
Earth System Model ◽  
System Model ◽  
Integration Time ◽  
Earth System ◽  
Near Surface ◽  
Intermediate Complexity ◽  
New Feature

Abstract. Here we describe GENIE-M, a new and improved version of the Grid ENabled Integrated Earth system model (GENIE), which is a 3-D earth system model of intermediate complexity. Main development goals of GENIE-M were to: (1) bring oceanic uptake of anthropogenic transient tracers within data constraints; (2) increase vertical resolution in the upper ocean to better represent near-surface biogeochemical processes; (3) calibrate the deep ocean ventilation with observed abundance of radiocarbon. We achieved all these goals through a transparent process of calibration that mostly consisted of objective model optimization. An important new feature in GENIE-M that dramatically improved the uptake of CFC-11 and anthropogenic carbon is the depth dependent vertical diffusivity in the ocean, which is spatially uniform in GENIE-1. In GENIE-M, biological production occurs in the top two layers above the compensation depth of 100 m and is modified, for example, by diagnosed mixed layer depth. In contrast, production in GENIE-1 occurs in a single layer with thickness of 175 m. These improvements make GENIE-M a well-calibrated model of intermediate complexity suitable for investigations of the global marine carbon cycle requiring long integration time.

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