Net Heat Flux Research Articles

Study of contact melting of plate bundles by molten material in severe reactor accidents

In a severe reactor accident, a crust will form on the surface of the molten material during the core melting process. The crust will have a contact melting with the internal components of the reactor. In this paper, the contact melting process of the molten material on the austenitic stainless steel plate bundles is studied. The contact melting model of parabolic molten material on the plate bundles is proposed, and the rule and main effect factors of the contact melting are analyzed. The results show that the melting velocity is proportional to the slope of the paraboloid, the heat flux and the distance between two plates D. The influence of melt gravity and the plate width on melting velocity is negligible. The thickness of the molten liquid film is proportional to the heat flux and plate width, and it is inversely proportional to the gravity. With the increase of D, the liquid film thickness decreases at first and then increases gradually. The liquid film thickness has a minimum against D. When the width of the plate is small, the width of the plate is the main factor affecting the thickness of the liquid film. The parameters are coupled with each other. In a severe reactor accident, the wider internal components of reactor, which can increase the thickness of the melting liquid film and reduce the net input heat flux from the molten material to the components, are the effective measures to delay the melting process.

Annual Cycle in Upper-Ocean Heat Content and the Global Energy Budget

Abstract As a major component of Earth’s energy budget, ocean heat content (OHC) plays a vital role in buffering climate change. The annual cycle is the most prominent change in OHC but has always been removed to study variations and changes in Earth’s energy budget. Here, we investigate the annual cycle of the upper-2000-m OHC at regional to global scales and assess the robustness of the signals using the spread of multiple observational products. The potential drivers are also investigated by comparing the annual OHC signal with the corresponding change in top-of-atmosphere radiation, surface heat flux, ocean heat divergence, and meridional heat transport. Results show that the robust signal of annual OHC change is significant down to a 1000-m depth globally and can reach down to 1500 m in some areas such as the tropical ocean. The global OHC (0–1500 m) changes from positive anomalies within September–February to negative anomalies within March–August, mainly because of the larger ocean area in the Southern Hemisphere and the seasonal migration of solar irradiance. Owing to the huge ocean heat capacity, the annual cycle of OHC dominates that of the global energy budget. The difference among the OHC annual cycles in the three major ocean basins is mainly attributed to ocean heat transport, especially in the tropics. In the upper 1500 m at mid- and high latitudes and in the upper 50 m of the tropics, the net sea surface heat flux dominates the OHC annual cycle, while in the tropics below 50 m, wind-driven Ekman heat transport associated with the geostrophic flow is the main driver.

Sea Surface Cooling by Rainfall Modulates Earth’s Heat Energy Flow

Abstract Characterizing the physical processes that modulate the continuous partitioning of heat between the ocean and overlying atmosphere is important for monitoring the subsequent flow of the heat accumulating in the ocean because of anthropogenic climate change. Oceanic rainfall sensible heat flux (Qp), whereby rainwater cools the sea surface, is computed and compared to the sea surface heat energy balance in the 60°N–60°S region. Contrary to popular belief, the results show that Qp is large at both short and long time scales, accounting for up to 22.5% of sea surface net heat flux around the 5.8°N line of latitude, 10.1% in the tropical 20°N–20°S region, and 5.7% in the global 60°N–60°S region. In the mixed layer of these same regions, area-average temperature change owing to a 10-yr accumulated Qp is up to −2.6° and −1.4°C, respectively. Further analysis reveals a previously unspecified rainfall–evaporation negative feedback between successive evaporation–rainfall cycles at the sea surface. The Qp depresses sea surface temperature and thus inhibits evaporation (latent heat flux), which in turn inhibits rainfall owing to decrease in water vapor supply to the atmosphere. The decrease in sea surface temperature also inhibits heat conduction from the ocean to the atmosphere (sensible heat flux). To compensate for the weaker latent and sensible heat fluxes, sea surface upward longwave radiation flux strengthens. We conclude that Qp acts like a modulator of Earth’s heat energy flow by controlling the partition of upper-ocean heat energy and the cycle of heat flow in the ocean and between the ocean and the atmosphere. Significance Statement Upper-ocean heat energy is partitioned between the ocean and the overlying atmosphere. Characterizing the physical processes that modulate this continuous partitioning is important for monitoring the subsequent flow of the heat energy accumulating in the ocean because of anthropogenic climate change. Here, we identify sea surface cooling by rainwater (oceanic rainfall sensible heat flux) as a modulator of this partition: this cooling depresses sea surface temperature and thus inhibits evaporation (latent heat flux), which in turn inhibits rainfall owing to the decrease in water vapor supply to the atmosphere; depressing sea surface temperature also inhibits heat conduction from the ocean to the atmosphere (sensible heat flux). To compensate for the weaker latent and sensible heat fluxes, sea surface upward longwave radiation flux strengthens.

Coupled Mode of Net Heat Flux and Wind Explain the Formation of the Indian Ocean Dipole

Coupled Mode of Net Heat Flux and Wind Explain the Formation of the Indian Ocean Dipole

Marine Heatwave Characteristics in the Makassar Strait and Its Surrounding Waters

This study aimed to investigate the characteristics of marine heatwaves (MHWs) in the Makassar Strait and adjacent waters (MSAW) using the Optimum Interpolation Sea Surface Temperature (OISSTv2) dataset from 1982 to 2021. The analysis revealed a significant positive trend in the frequency and duration of MHWs, while the mean and maximum intensities displayed a negative trend over the 40-year period. By examining two different phases of the Pacific Decadal Oscillation (PDO), it was observed that the cold phase (more frequent La Niña events than El Niño) had higher MHW frequency and duration, whereas the warm phase (more frequent El Niño events than La Niña) exhibited higher mean and maximum intensities. Moreover, the occurrence of high-intensity MHWs was associated with weakened winds, the decaying phase of El Niño and positive Indian Ocean Dipole (IOD), and high net surface heat flux (NSHF). An intriguing finding emerged, indicating a notable lag of 7–9 months (10 months) between El Niño (positive IOD) events and the emergence of high-intensity MHWs. This lag suggests that MHWs are more likely to manifest during the transition towards La Niña and negative IOD conditions. Additionally, the study highlighted a stronger correlation between the El Niño–Southern Oscillation and MHW intensity in the MSAW compared to the IOD. Furthermore, the different intensities of MHWs were found to be linked to NSHF, which exhibited higher values during the warm phase of the PDO compared to the cold phase.

Radiation-Induced Thermal Runaway Propagation in a Cylindrical Li-Ion Battery Pack: Non-Monotonicity, Chemical Kinetics, and Geometric Considerations

Li-ion batteries play a key role in energy storage and conversion in engineering systems such as electric vehicles and grid energy storage, with critical impact on electrification and storage of renewable energy. A key unresolved technological challenge in Li-ion batteries pertains to thermal runaway initiation and propagation in a battery pack, which can lead to subsequent fire and explosion. Despite significant past work, there remains a critical need to understand how thermal runaway propagates in a pack. This work presents a comprehensive investigation of the effect of radiative heat transfer on thermal runaway propagation. Radiation can be important when a battery is exposed to adjacent heat and fire sources, as well as in thermal runaway propagation from one hot cell to another. A theoretical radiative heat transfer model based on view factor theory is developed. Calculations based on this model for a simple 2D cylinder-to-cylinder geometry are found to be in very good agreement with analytical expressions. Radiation-induced thermal runaway propagation between two cylindrical 18650 batteries is evaluated. It is shown that radiation may play a key role in thermal runaway propagation, depending strongly on the triggering temperature. It is found that radiative effects in thermal runaway propagation exhibit both nonlinear and non-monotonic characteristics. At high temperatures, thermal runaway is triggered rapidly in the region close to the battery surface, where the chemical reactions are strongly coupled, and radiation plays a dominant role. In contrast, at lower temperatures, thermal runaway is triggered much more slowly and towards the core of the cell, where some chemical reactions may be decoupled, and pre-runaway chemical heat release plays an increasingly important role. The results presented here suggest that radiation can either facilitate or mitigate thermal runaway. The net radiation heat flux has a cross-over instant, beyond which radiation starts to retard thermal runaway. Additionally, the blocking effect in radiative heat transfer between cells arranged in equal-spacing homogenous or orthogonal arrangements in a battery pack is investigated, along with the effect of the hot spot size. Results from this work help understand the role of radiation in thermal runaway propagation and provide useful insights into the thermal runaway control and design of safe Li-ion battery packs.

Measuring firebrand heat flux with a thin-skin calorimeter

While the impact of wildland-urban interface fires is growing, firebrand exposure is a significant but not well understood contributor to fire spread. The ignition threat of firebrand exposures can be characterized by measuring the heat transfer of glowing firebrands to a surface. The current study presents a novel method for conducting time-resolved heat transfer measurements from individual firebrands across a range of flow conditions. Experiments are conducted with individual glowing firebrands generated from birch discs and placed on a copper thin skin calorimeter of the same diameter, which is embedded in the substrate. The net heat flux from the firebrand to the thin skin calorimeter is obtained from the thermal energy storage in the thin skin calorimeter, plus heat conduction losses to the substrate. Values of peak net heat flux, total heating, duration of heating are reported under different flow conditions from 0.05 m/s to 1.6 m/s. The average peak net heat flux for the disc-shaped birch firebrands is 45 kW/m2, and does not change significantly with flow condition. However, there is an increase in the total heating, duration of heating, and total mass consumed as the flow velocity increases.

Insights on Simulating Summer Warming of the Great Lakes: Understanding the Behavior of a Newly Developed Coupled Lake‐Atmosphere Modeling System

AbstractThe Laurentian Great Lakes are the world's largest freshwater system and regulate the climate of the Great Lakes region, which has been increasingly experiencing climatic, hydrological, and ecological changes. An accurate mechanistic representation of the Great Lakes thermal structure in Regional Climate Models (RCMs) is paramount to studying the climate of this region. Currently, RCMs have primarily represented the Great Lakes through coupled one‐dimensional (1D) column lake models; this approach works well for small inland lakes but is unable to resolve the realistic hydrodynamics of the Great Lakes and leads to inaccurate representations of lake surface temperature (LST) that influence regional climate and weather patterns. This work overcomes this limitation by developing a fully two‐way coupled modeling system using the Weather Research and Forecasting model and a three‐dimensional (3D) hydrodynamic model. The coupled model system resolves the interactive physical processes between the atmosphere, lake, and surrounding watersheds; and validated against a range of observational data. The model is then used to investigate the potential impacts of lake‐atmosphere coupling on the simulated summer LST of Lake Superior. By evaluating the difference between our two‐way coupled modeling system and our observation‐driven modeling system, we find that coupled‐lake atmosphere dynamics can lead to a higher LST during June‐September through higher net surface heat flux entering the lake in June and July and a lower net surface heat flux entering the lake in August and September. The unstratified water in June distributes the entering surface heat flux throughout the water column leading to a minor LST increase, while the stratified waters of July create a conducive thermal structure for the water surface to warm rapidly under the higher incoming surface heat flux. This research provides insight into the coupled modeling system behavior, which is critical for enhancing our predictive understanding of the Great Lakes climate system.

Increasing Shortwave Penetration Through the Bottom of the Oceanic Mixed Layer in a Warmer Climate

AbstractShortwave penetration (Qpen) through the bottom of the oceanic mixed layer (ML) profoundly affects the thermal structure in the upper ocean and consequently contributes to sea surface temperature (SST) change, which has not been adequately understood under global warming. Here, using ensemble earth system model simulations under a high‐emissions scenario (SSP5‐8.5), we investigate the Qpen change and related effects on some oceanic parameters, which are regionally dependent. It is found that globally averaged Qpen typically increased by 2.49 ± 0.83 W m−2 in the second half of the 21st century, which is comparable to an increase in the net surface heat flux (3.01 ± 0.31 W m−2), corresponding to an increase in SST by 3.07 ± 0.83°C. Although there exist substantial intermodel uncertainties in the projected chlorophyll change, the shoaled ML contributes the most of the increase in Qpen in the global ocean, whereas in the tropical ocean, the reduction in the chlorophyll concentration plays an equivalent role with the mixed layer depth in determining Qpen change. The ML heat budget indicates that the enhanced Qpen leads to surface cooling through a decrease in the surface net surface heat flux. However, the cooling is compensated for by a warming effect from ocean dynamical change due to more shortwave penetration into the subsurface layer, leading to a small net effect on the ML heat budget. It is suggested that the impact of Qpen on the global oceanic ML heat balance needs to be adequately recognized.

Role of Ocean Advections during the Evolution of the Pacific Meridional Modes

Abstract The Pacific meridional modes (PMMs) are the leading ocean–atmosphere coupled modes in the subtropical northeastern (NPMM) and southeastern (SPMM) Pacific, respectively, and have been suggested to be key precursors to equatorial Pacific variability. Previous studies pointed out that both NPMM- and SPMM-related sea surface temperature (SST) anomalies are primarily driven by net surface heat flux variations during their equatorward evolution. However, whether oceanic heat advective processes would play a role during the evolution remains unclear. To address this issue, we perform an ocean mixed layer heat budget analysis based on observations and three ocean reanalysis datasets, and then reveal the effect of ocean advections on the evolution by comparing a fully coupled dynamic ocean model (DOM) to a slab ocean model (SOM). Our results suggest that for the NPMM evolution, ocean advections—primarily by anomalous meridional Ekman heat advections driven by mean and anomalous zonal wind stresses—play a damping role in the south of the NPMM. Thus, the NPMM SST anomalies appear to instead exhibit a poleward shift, although still freely propagating westward from the preceding boreal winter to the following summer. This finding challenges the traditional view that the NPMM propagates equatorward through the wind–evaporation–SST feedback. For the SPMM evolution, ocean advections play a damping role in the center of the SPMM from boreal spring to summer, as well as an intensification role in the southwest Pacific during summer. However, the effect of the intensification on the SPMM evolution is hard to determine due to the strong simulation bias of the SPMM evolution in the DOM. Significance Statement While it is known that both NPMM- and SPMM-associated SST anomalies are primarily driven by net surface heat flux variations during their evolution, whether ocean advections would play a role remains unknown. Here, we show that ocean advections play a role in the evolution of both PMMs. In particular, for the NPMM evolution, ocean advections play a damping role in the south of the NPMM center, causing a tendency for the NPMM to be displaced northward. The role of ocean advection challenges the prevailing notion that the NPMM simply evolves equatorward through the wind–evaporation–SST feedback.

Interdecadal Variation of Spring Extreme High-Temperature Events in the Western Tianshan Mountains and Its Relationship with the Tropical SST

This study performed an observational analysis to examine the interdecadal variation in the frequency of extreme high-temperature events (EHEs) during spring over the western Tianshan mountain, China, which were characterized by relatively fewer (more) EHEs during 1983–1996 (2000–2015). A composite analysis indicated that the interdecadal increase in EHEs is closely related to a deep dynamic anomalous Iranian high. Under the control of this high system, the water vapor content decreased over the western Tianshan mountains, and atmospheric circulation was dominated by a descending motion. Both were attributed to the decreased cloud cover, inducing a cloud-forced net solar radiation increase. The short-wave radiation flux and sensible heat flux reaching the surface increased, and the net surface heat flux increased cumulatively, which was conducive to the surface temperature increase and EHE occurrence. The anomalous Iranian high responsible for ECEs occurrence was related to the air-sea interaction over the Atlantic and Indo-Pacific. The latitudinal sea surface temperature (SST) difference between the tropical western Pacific and the western Indian Ocean directly strengthens the Walker circulation and thus enhances the Iranian high. In addition, the anomalous Iranian high was affected by the atmospheric wave trains at middle latitude, which was triggered by the warm anomaly of the Atlantic SST.

Characteristics of Marine Heatwaves in the Indonesian Waters during the PDO, ENSO, and IOD Phases and Their Relationships to Net Surface Heat Flux

We conducted an investigation into the characteristics of marine heatwaves (MHWs) in Indonesian waters, aiming to understand the underlying mechanisms responsible for their formation, particularly the ones generated by net surface heat flux. To accomplish this, we utilized remote sensing data from the National Oceanic and Atmospheric Administration and the European Centre for Medium-Range Weather Forecasts. The dataset covered a 40-year period (1982–2021) encompassing both warm (1982–2007) and cold (2008–2021) phases of the Pacific Decadal Oscillation (PDO). Statistical analysis methods were employed to process the data. Our study reveals significant findings regarding MHWs in Indonesian waters. We observed the highest average frequency and maximum intensity of MHWs, occurring approximately 2–3 times a year and exceeding 1.5 °C, respectively, during the warm phase of PDO (with El Niño events occurring more frequently than La Niña). Conversely, the longest durations of MHWs in Indonesian waters were recorded during the cold phase of PDO (with La Niña events occurring more frequently than El Niño), spanning approximately 7–15 days. We identified local forcing in the form of net surface heat flux as the primary driver of MHW frequency and maximum intensity. During the warm phase of PDO, the net surface heat flux was notably higher, primarily due to increased shortwave radiation (heat gain) and reduced latent heat flux (heat loss) through the evaporation process. These factors collectively contributed to maintaining warmer ocean temperatures. Moreover, our study provides valuable insights into the interannual variability of MHWs through the application of composite calculations. We discovered a strong correlation between the occurrence of El Niño and positive Indian Ocean Dipole (IOD) events during the warm PDO phase and the highest frequency and maximum intensity of MHWs, with approximately 2.52 events and 1.54 °C, respectively. In contrast, we found that MHWs with the longest durations were closely linked to La Niña and negative IOD events during the cold PDO phase, lasting approximately 10.90 days. These findings highlight the complex interplay between climate phenomena and MHW characteristics, further deepening our understanding of their dynamics.

Numerical and experimental study for a modified LPG cooking burner

A new modification of the LPG burner (NB-5) is proposed in this study. The modification combines the advantageous features that originated from three Thai commercial burners: KB-5, S-5, and EB-5. CFD techniques were used to investigate and prove the benefits each burner’s features. Combining features increase the mixing intensity and primary aeration, generates a swirling central flame, reduces heat loss, and increases secondary aeration. These enhancements cause an increase in combustion temperature and flow velocity, which significantly improves the net heat flux of the NB-5. The simulation results indicated that the NB-5 produced the highest average temperature of 929.35 K, and the highest heat flux of 58.01 kW/m2. This leads directly to an enhancement in thermal efficiency. The new modification burner (NB-5) was built and tested experimentally based on CFD results. The NB-5 burner obtained significant improvements in thermal efficiency and a reduction in CO and NOx emissions over the three commercial burners. In comparison with the traditional KB-5 burner, it was found that the NB-5, EB-5, and S-5 burners provided average energy savings of 22.37%, 8.46%, and 1.69%, respectively. This study shows the benefit of utilizing the CFD simulations to assist in designing and modifying LPG burners. This allows manufacturers to design and optimize burners more effectively at a much lower cost than the traditional water boiling tests.

Interpretation of Net Surface Heat Fluxes and Meridional Overturning Circulations in Global Coupled HadGEM3 Climate Simulations

Abstract The annual mean net surface heat fluxes (NSHFs) from the ocean to the atmosphere generated by historical forcing simulations using the HadGEM3-GC3.1 coupled climate model are shown to be relatively independent of resolution, for model horizontal grid spacings between 1° and 1/12°, and to agree well with those based on the DEEP-C (Diagnosing Earth’s Energy Pathways in the Climate System) analyses. Interpretations of the geographical patterns of the NSHFs are suggested that use basic ideas extracted from the theory of the ventilated thermocline and planetary geostrophic layer models. As a step toward investigation of the validity of the assumptions underlying the interpretations, we examine the contributions to the rate of change of the active tracers from the main terms in their prognostic equations as a function of the active tracer and latitude. We find that, consistent with our assumptions, the main contributions from vertical diffusion occur in “near-surface” layers. We also find that, except at high latitudes, the sum of the NSHF and vertical diffusion is mainly balanced by time-mean advection of potential temperature. A corresponding statement holds for potential density but not salinity. We also show that the heat input by latitude bands is dominated by the NSHFs, the time-mean advection, and the equatorial Pacific. It is usually assumed that global integrals of tracer tendencies due to advection as a function of the tracer should be identically zero. We show that nonnegligible contributions to them arise from net freshwater surface fluxes. Significance Statement Our aim is to understand better how the heat and freshwater that are input into the ocean from the atmosphere are then redistributed within the ocean and released back into the atmosphere. We show that the geographical patterns of the heat that is input to or released from the ocean surface in coupled climate models agree well with observations. We outline a dynamically based interpretation of these surface fluxes and provide evidence that supports some of its assumptions. This work might in future help us to understand how the patterns of the surface fluxes will respond to changes in greenhouse gas forcing.

Tracing Oceanic Sources of Heat Content Available for Atlantic Hurricanes

AbstractIn the Main Development Region (MDR) for Atlantic hurricanes, the volume of water warmer than 26.5°C quantifies the potential source of energy for major storms. Taking a Lagrangian perspective, this warm water is backtracked on seasonal timescales in an eddy‐resolving ocean model hindcast spanning 1988–2010. Being confined near the surface and assuming a mixed layer depth of 50 m, net heat fluxes into or out of water parcels advected toward the MDR are inferred from along‐trajectory temperature tendencies. To first order, these heat fluxes match surface net heat fluxes during the months over which water advects into the region. Contributions to this warm water in the preceding 6 months include water resident in the MDR (20%–40%), arriving via the North Brazil Current (NBC, 5%–15%), or via Ekman drift across 10°S. In relative terms, decreased contributions from the NBC and Ekman drift and more in situ warming within the MDR lead to warmer, more active hurricane seasons.

Trend of annual and semiannual harmonics of sea surface temperature in the tropical Indian Ocean, 1979–2018

In the Indian Ocean (IO), the annual and semiannual oscillations of the sea surface temperature (SST) contribute more than 80% of the total variance. It is known that the SST in the tropical IO has warmed at a rate of 0.15 °C/decade since 1979. However, such an estimate of the decadal trend of the annual and semiannual harmonics of SST remains unknown, despite being a strong component of the SST signal. Here we use a widely accepted data product (TropFlux) to quantify the annual and semiannual harmonics in the tropical IO for the first time. The northern IO has a distinctly strong semiannual cycle (1–1.8 °C), which is showing an amplifying trend (∼ 0.04 °C/decade) since 1979. Furthermore, a damping trend in annual amplitude exists over much of the IO, except along the northwestern Bay of Bengal, the Seychelles-Chagos thermocline ridge, the Persian Gulf, and the Indonesian throughflow region. The estimated damping of the annual amplitude is highest over the Arabian Sea. In contrast, the southern tropical IO has a predominant annual cycle, the amplitude of which has weakened during 1979–2018. In the north IO, net air-sea heat flux and vertical processes show a dominant semiannual harmonic oscillation similar to SST. Additionally, the annual amplitude is influential over southern IO. Horizontal advection contributes significantly along the boundary-current regions and the western equatorial IO. Our analysis of combined annual and semiannual cycles shows significant warming in the tropical IO during October–November and cooling during July–August owing to the amplification of semiannual oscillation. These changes in the SST can influence air-sea interaction processes such as cyclogenesis and monsoon.

Upper-Oceanic Warming in the Gulf of Mexico between 1950 and 2020

Abstract We estimate ocean heat content (OHC) change in the upper 2000 m in the Gulf of Mexico (GOM) from 1950 to 2020 to improve understanding of regional warming. Our estimates are based on 192 890 temperature profiles from the World Ocean Database. Warming occurs at all depths and in most regions except for a small region at northeastern GOM between 200 and 600 m. GOM OHC in the upper 2000 m increases at a rate of 0.38 ± 0.13 ZJ decade−1 between 1970 and 2020, which is equivalent to 1.21 ± 0.41 terawatts (TW). The GOM sea surface temperature (SST) increased ∼1.0° ± 0.25°C between 1970 and 2020, equivalent to a warming rate of 0.19° ± 0.05°C decade−1. Although SST in the GOM increases at a rate approximately twice that for the global ocean, the full-depth ocean heat storage rate in the GOM (0.86 ± 0.26 W m−2) applied to the entire GOM surface is comparable to that for the global ocean (0.82–1.11 W m−2). The upper-1000-m layer accounts for approximately 80%–90% of the total warming and variations in the upper 2000 m in the GOM. The Loop Current advective net heat flux is estimated to be 40.7 ± 6.3 TW through the GOM. A heat budget analysis shows the difference between the advective heat flux and the ocean heat storage rate (1.76 ± 1.36 TW, 1992–2017) can be roughly balanced with the annual net surface heat flux from ECCO (−37.9 TW).

Impact of Stratospheric Geoengineering on Sea Surface Temperature in the Northern Gulf of Guinea

Among techniques proposed to limit global warming, there is Stratospheric Aerosol Geoengineering (SAG) which is aiming to increase Earth-atmosphere albedo by injecting sulfur dioxide into the stratosphere in order to reduce the solar radiation that reaches the earth. This study aims to assess the potential impact of SAG on Sea Surface Temperature (SST) in the Northern Gulf of Guinea and its causes using GLENS (Geoengineering Large Ensemble) simulations performed under a high anthropogenic emission scenario (RCP8.5). Here, we focus on two dynamically different regions: Sassandra Upwelling in Côte d’Ivoire (SUC, located east of Cape Palmas) and Takoradi Upwelling in Ghana (TUG, located east of Cape Three Points). Results show that in the SUC region, under climate change, there is an increase in SST (referred to as the current climate) all year long (by 1.52 °C on average) mainly due to an increase in net heat flux (lead by the decrease in longwave radiation) and also in weak vertical mixing (caused by strong stratification which dominates the vertical shear). Under SAG, SST decreases all the seasonal cycle with its maximum in December (−0.4 °C) due to a reduction in the net heat flux (caused by a diminution of solar radiation) and an increase in vertical advection (due to an increase in vertical temperature gradient and vertical velocity). In the TUG region, under climate change, SST warming is a little more intense than in the SUC region and SST changes are driven by an increase in the net heat flux and strong stratification. The cooling of the SST in TUG is similar to the SUC region, but contrary to this region, the cooling under SAG is not only explained by a decrease in the net heat flux but also by the remote forcing of wind changes at the western equatorial Atlantic.

Ocean Warm Skin Signals Observed by Saildrone at High Latitudes

AbstractThe existence of a cool sea surface skin layer in the global ocean during both day and night is generally recognized. However, a warm skin should be present if the total surface net heat flux () were to be from the atmosphere into ocean. Saildrone, an advanced uncrewed surface vehicle, has been shown to be able to provide sufficiently accurate sea skin temperature (SSTskin) and subsurface temperature (SSTdepth) data at high latitudes. Using those SST data along with meteorological parameters from a Saildrone deployed in the Arctic in the summer of 2019, some warm skin layers were identified due to the gain resulting from the combined effect of positive air‐sea temperature difference, humid surface air and cloudy skies. Furthermore, most warm skins here were found during and shortly after rainfall events. It is essential to incorporate the ability to simulate warm skin layers in the present cool skin models.

Geotemperature, net heat flow from the soil and morphological variables of the soybean crop (Glycine max L.) under plastic mulch conditions

Most crops are affected by various factors, plastic mulch emerges as an alternative, causing a positive impact on the temperature in the root zone, microbial life and the physical properties of the soil associated with the improvement of crop yield. The objective of the research was to evaluate the yield of the soybean crop (Glycine max L.) under plastic mulch conditions. Geotemperature parameters, net heat flow from the soil and morphological variables were analyzed. The completely randomized design was used, the study factor was plastic mulch of different colors: black (T1), red (T2), blue (T3), and green (T4) and the control (T0, bare ground). The results showed that the plastic mulch influences the soil temperature up to 6 °C with respect to the bare soil (T4) and the net heat flux, the black and green colors are relevant, as well as the morphological variables, being the treatments T3 and T4, the ones that had the best results compared to bare soil, improving crop yield up to 2 t ha-1. Blue and green plastic mulch is a viable option to improve soybean productivity and economic performance.