Influence Of Sea Surface Temperature Research Articles

Effect of sea surface temperature on sea surface brightness temperature measured by L-band microware radiometers

The effect of sea surface temperature (SST) on sea surface brightness temperature measured by L-band microware radiometers is estimated in this paper. We found systematic SST dependence in Aquarius radar backscatter σ0, radiometer excess emissivity Δe as well as sea surface excess brightness temperature ΔTb. The influences of SST on σ0, Δe and ΔTb in cold water are much more bigger than that in warm water. The precision of the corrected measured flat sea surface bright temperature is improved significantly after correcting with SST.

Influence of Sea Surface Temperature on Simulated Future Change in Extreme Rainfall in the Asia-Pacific

The changes in precipitation simulated by the 40-model CMIP5 ensemble for the Asia-Pacific region are assessed, focusing on the two periods 1986–2005 and 2080–2099 under the RCP8.5 scenario. The frequency distributions of both daily and monthly mean rain rates at model grid points in each of four seasons are considered. In spatial averages for the land domain and seven selected regions, there is both an increase in the frequency of dry days and a shift towards heavier rain. Three 20-year seasonal aggregate statistics, the mean, the top decile of monthly amounts, and top percentile of daily amounts are assessed. The percentage changes over land are on average 4% higher for monthly extremes than for the mean, and a further 10% higher for the daily extremes. Over Australia and central Indonesia in some seasons the mean decreases but daily extremes increase. In much of Asia the daily extremes increase by 30% or more. For these statistics, there is a range across the ensemble that can often be linked to a pattern of sea surface temperature change that is quantified by a Pacific-Indian Dipole (or difference, PID) index. Correlations with both mean and extreme rain are highly negative over Australia and Indonesia and moderately positive over parts of south and east Asia in some seasons. The mechanism for this is explored through additional simulations and links with water vapour path. The results provide some understanding of the range of projections of future rainfall change based on the CMIP5 results, with some potential for narrowing it.

Estimating the Role of SST in Atmospheric Surface Wind Variability over the Tropical Atlantic and Pacific

Abstract The influence of sea surface temperature (SST) on interannual surface wind variability in the tropical Atlantic and Pacific is estimated using sensitivity experiments with the SINTEX-F GCM and the ensemble spread in a nine-member control simulation. Two additional estimates are derived for both SINTEX-F and the ERA-Interim reanalysis using regression analysis and singular value decomposition. All methods yield quite consistent estimates of the fraction of surface wind variability that is determined by SST and therefore potentially predictable. In the equatorial Atlantic, analysis suggests that for the period 1982–2014 approximately 2/3 of surface zonal wind variability in boreal spring and early summer is potentially predictable, while 1/3 is due to noise. Of the predictable component, up to about 35% may be driven from outside the tropical Atlantic, suggesting an important role for remote forcing and a diminished one for local feedbacks. In the northern tropical Atlantic, only 30% of boreal winter variability is predictable, most of which is forced from the Pacific. This suggests a minor role for local coupled air–sea feedbacks. For the equatorial Pacific, the results suggest high predictability throughout the year, most of which is due to local SST, with the tropical Atlantic only playing a minor role in boreal summer. In the tropical Atlantic, atmospheric internal variability is strongly dependent on the presence of deep convection, which, in turn, is related to mean SST. A similar, but weaker, state dependence of internal variability is evident in the tropical Pacific.

Influence of sea surface temperature in the tropics on the Antarctic sea ice under global warming

Sea ice fields in the Antarctic, in contrast to the Arctic ones, did not show a reduction in observed global warming, whereas the global climate models indicate its certain decrease. The purpose of the study is to explain this climatic phenomenon on the basis of the idea of joint dynamics of oceanic structures in the Southern Ocean – the Antarctic polar front and the margin of the maximum distribution of sea ice. We used data from the ERA/Interim and HadISST as well as the database on the sea ice for 1979–2017. Relationship between the SST-anomalies in low latitudes of the Northern hemisphere and positions of the Antarctic polar front and maximum sea-ice extent was investigated. It was found that locations of these structures changed under the influence of the SST anomalies in low latitudes. The results obtained confirm existence of the opposite trends in changes in the sea ice extent in the Arctic and Antarctic under the influence of the SST anomalies in the central North Atlantic Ocean. When positive, the anomalies cause a shift of the Intertropical Convergence Zone (ITCZ) and the Hadley circulation to the North, while, on the contrary, the negative anomaly promotes the corresponding shift of the Antarctic polar front, followed by the boundary of sea ice.

Sensitivity of Midlatitude Heavy Precipitation to SST: A Case Study in the Sea of Japan Area on 9 August 2013

AbstractThis study investigates the influence of sea surface temperature (SST) over the Sea of Japan on a heavy precipitation event that occurred over the northern part (Northern Tohoku region) of Japan's largest island on 9 August 2013. Sensitivity experiments with the Weather Research and Forecasting model show that warmer (cooler) SSTs prescribed over the Sea of Japan in the simulations lead to an increase (decrease) in 24‐hr precipitation averaged within the Northern Tohoku region, especially on the Sea of Japan (i.e., windward) side. Though no significant relationship is found between the local maxima and SSTs over the Sea of Japan, those SST values over the Sea of Japan affect the evolution of the intense convective precipitation; higher (lower) SSTs act to shift the location of intense precipitation on the upwind (downwind) side in the present event. The different evolution results in a different interaction with the downstream orography, leading to no significant relationship between the local maxima of intense precipitation and SSTs. The differences arise from the sensitivity of convective updraft to SSTs. The simulations thus suggest that uncertainties in currently available SST products may alter both the area‐averaged precipitation and the geographical locations of intense precipitation, which can potentially impact flash flood and landslide warnings.

Tropical Pacific sea surface temperature influence on seasonal streamflow variability in Ecuador

This study presents a basin‐wide assessment about the spatiotemporal variability of streamflows in Ecuador for the period 1979–2015. The influence of the tropical Pacific sea surface temperature (SST) on streamflow variability from February to April (FMA) period, as the months showing maximum streamflow for the wet season in Ecuador, and from June to August (JJA), corresponding to the dry season, was analysed. First, a long‐term trend analysis was carried out by applying the Sen's slope estimator and the Mann–Kendall test to monthly streamflow data from 45 gaging stations located in different basins across Ecuador. While the coastal region showed the highest generalized positive trends from July to January, the results for the Pacific Andean area suggested a strengthening of the seasonality, presenting an overall increase in the streamflow for all months except August, September and October, which showed negative trends. Second, a singular‐value decomposition (SVD) was applied in order to find the main coupled variability patterns between the FMA streamflow and the quasi‐coetaneous SST (December–February [DJF]) and between the JJA streamflow and the coetaneous SST. The results revealed two main coupled modes for DJF SST/FMA streamflow, the first associated with the canonical El Niño and the second with El Niño Modoki. The latter exerted a major influence on FMA streamflow over most of Ecuador. For JJA streamflow, however, the pattern associated with the traditional El Niño was even more relevant. These results establish the foundations for streamflow modelling in Ecuador based on the Pacific SST, showing the strong response of the streamflows to different types of El Niño events.

Mechanisms causing east Australian spring rainfall differences between three strong El Niño events

Strong El Nino events have had significant impacts on society through their association with extreme events, such as droughts and floods. However, questions remain as to the robustness of strong El Nino events in forcing regional climate variability. The strong 1982, 1997 and 2015 El Nino events were of similar type and strength, but in eastern Australia they were associated with differing spring rainfall anomaly magnitudes and patterns. To understand these differences, we first determined the most important processes for teleconnecting the El Nino signal to east Australian spring rainfall using historical relationships with winds and sea level pressure. Then, using a 60-member atmospheric model ensemble, we estimated the influence of sea surface temperatures (SSTs) on Australian atmospheric circulation and rainfall during these three El Nino events relative to internal variability. We found that the different east Australian spring rainfall anomalies for each of the three El Nino events are best explained by differences in the strength of the meridional wind component of the regional circulation. All three El Nino events exhibited a positive sea level pressure anomaly to the south of Australia, which was associated with rainfall deficits along the southeast Australian coast. The experiments indicate the regional atmospheric circulation and rainfall differences were forced by SSTs during spring of 1982 and 1997, with their influence on the circulation in 2015 remaining unclear. We also show that SSTs adjacent to Australia further contributed to the modelled rainfall differences mainly by regulating moisture availability.

Prediction of summer rainfall over the source region of the Blue Nile by using teleconnections based on sea surface temperatures

Summer rainfall (June–September) accounts for about 80% of the annual rainfall in the Lake Tana basin of Ethiopia, the source region of the Blue Nile River. Prediction of summer rainfall would be valuable for managing the region’s water resources and agricultural operations. This study investigated the influence of sea surface temperature (SST) as a predictor of summer rainfall in the basin by applying cross-correlation analysis between summer rainfall and climatic indices and SST in various oceanic regions from 1985 to 2015. Summer rainfall showed a strong negative correlation (− 0.619) with the Pacific Decadal Oscillation index at short time lags. Further analysis identified strong teleconnections (|r| ≥ 0.5) between SSTs in specific parts of the Pacific Ocean and summer rainfall in the Lake Tana basin, raising the possibility of predicting summer rainfall from Pacific SSTs with a lead time of 4 to 5 months. Average SSTs of an area near the Philippines and an area west of North America were positively correlated (0.629) and negatively correlated (− 0.538), respectively, with summer rainfall in the Lake Tana basin. Predictions of summer rainfall from these teleconnected SSTs by an Elman recurrent neural network model were encouraging, indicating a strong correlation (r > 0.77) between the observed and predicted summer rainfall. Our results suggest that neural network techniques may have sufficient skill to support seasonal rainfall predictions over the Lake Tana basin.

Towards a 'Sea-Level Sensitive' dynamic model: impact of island ontogeny and glacio-eustasy on global patterns of marine island biogeography.

A synthetic model is presented to enlarge the evolutionary framework of the General Dynamic Model (GDM) and the Glacial Sensitive Model (GSM) of oceanic island biogeography from the terrestrial to the marine realm. The proposed 'Sea-Level Sensitive' dynamic model (SLS) of marine island biogeography integrates historical and ecological biogeography with patterns of glacio-eustasy, merging concepts from areas as diverse as taxonomy, biogeography, marine biology, volcanology, sedimentology, stratigraphy, palaeontology, geochronology and geomorphology. Fundamental to the SLS model is the dynamic variation of the littoral area of volcanic oceanic islands (defined as the area between the intertidal and the 50-m isobath) in response to sea-level oscillations driven by glacial-interglacial cycles. The following questions are considered by means of this revision: (i) what was the impact of (global) glacio-eustatic sea-level oscillations, particularly those of the Pleistocene glacial-interglacial episodes, on the littoral marine fauna and flora of volcanic oceanic islands? (ii) What are the main factors that explain the present littoral marine biodiversity on volcanic oceanic islands? (iii) How can differences in historical and ecological biogeography be reconciled, from a marine point of view? These questions are addressed by compiling the bathymetry of 11 Atlantic archipelagos/islands to obtain quantitative data regarding changes in the littoral area based on Pleistocene sea-level oscillations, from 150 thousand years ago (ka) to the present. Within the framework of a model sensitive to changing sea levels, we discuss the principal factors affecting the geographical range of marine species; the relationships between modes of larval development, dispersal strategies and geographical range; the relationships between times of speciation, modes of larval development, ecological zonation and geographical range; the influence of sea-surface temperatures and latitude on littoral marine species diversity; the effect of eustatic sea-level changes and their impact on the littoral marine biota; island marine species-area relationships; and finally, the physical effects of island ontogeny and its associated submarine topography and marine substrate on littoral biota. Based on the SLS dynamic model, we offer a number of predictions for tropical, subtropical and temperate volcanic oceanic islands on how rates of immigration, colonization, in-situ speciation, local disappearance, and extinction interact and affect the marine biodiversity around islands during glacials and interglacials, thus allowing future testing of the theory.

Role of Atlantic air\u2013sea interaction in modulating the effect of Tibetan Plateau heating on the upstream climate over Afro-Eurasia\u2013Atlantic regions

Previous studies have demonstrated that atmospheric diabatic heating over the Tibetan Plateau (TP) exerts significant influences on the “upstream” climate of the Atlantic-African-European sector in boreal summer. Using the NCAR Community Earth System Model, this study demonstrates that the TP-induced change in North Atlantic sea surface temperature (SST) including evident warming over the mid-latitude North Atlantic and cooling over the south can in turn modulate the above TP impact. Compared with the TP heating experiment without Atlantic SST variation, anomalous wave train pattern appears with north-northeastward downstream influences when the change in Atlantic SST is considered. The wave train pattern is characterized by three positive centers over the North Atlantic, the Arctic Ocean, and east of Japan, and four negative centers over northeastern North America, North Europe, the mid-Atlantic, and the northwestern Pacific. It intensifies the northern portions of the TP-induced tropospheric anticyclones over the extratropical North Atlantic and the cyclones over northeastern North America and North Europe. Correspondingly, precipitation decreases over the northwestern Atlantic but increases over northeastern North America and North Europe. Due to the easterly anomalies on the southern side of the weakened thermal low over subtropical Africa, precipitation over the Sahel decreases, indicating a weakening of TP-induced precipitation dipole over the tropical eastern Atlantic and West Africa when the Atlantic SST influence is considered. Overall, the modulation of Atlantic SST variation accounts for above 20 percent of the upstream climate signals induced by the TP thermal effect.

Assessing the dendroclimatic potential of Nothofagus betuloides (Magellan\u2019s beech) forests in the southernmost Chilean Patagonia

Key messageTree growth of Nothofagus betuloides forests south of 50°S is affected by local temperature and precipitation together with large-scale high-latitude climate patterns, but also significant influences from the Tropical Pacific were found.The characterization of past climate dynamics in southern South America is difficult due to the shortness of instrumental data. However, abundant forests in the southernmost part of the continent makes it an ideal place to assess the dendroclimatological potential for developing high-resolution climate proxy time series to extend the observations back in time. Whereas the majority of dendroclimatological studies have focused on latitudes north of 50°S, we present six new Magellan’s beech (Nothofagus betuloides (Mirb.) Oerst.) tree-ring width (TRW) chronologies, spanning between 202 and 500 years, developed from southernmost Patagonia (> 50°S), Chile. The climate signal in the trees was analyzed using local station data, regional sea surface temperature (SST) and large-scale atmospheric indices: the Southern Oscillation Index (SOI) and the southern annual mode (SAM). The correlations between individual site chronologies and observed summer temperatures and precipitation varied, reflecting diverse microsite conditions and local scale geographic patterns. An influence of southern Pacific SST was evident at two of the northern sites. Although the associations with SOI and SAM were weak, the influence of regional sea level pressure on tree growth in the region was evident.

Attributing human influence on the July 2017 Chinese heatwave: the influence of sea-surface temperatures

On 21–25 July 2017 a record-breaking heatwave occurred in Central Eastern China, affecting nearly half of the national population and causing severe impacts on public health, agriculture and infrastructure. Here, we compare attribution results from two UK Met Office Hadley Centre models, HadGEM3-GA6 and weather@home (HadAM3P driving 50 km HadRM3P). Within HadGEM3-GA6 July 2017-like heatwaves were unequaled in the ensemble representing the world without human influences. Such heatwaves became approximately a 1 in 50 year event and increased by a factor of 4.8 (5%–95% range of 3.1 to 8.0) in weather@home as a result of human activity. Considering the risk ratio (RR) for the full range of return periods shows a discrepancy at all return times between the two model results. Within weather@home a range of different counterfactual sea surface temperature (SST) patterns were used, whereas HadGEM3-GA6 used a single estimate. The global mean difference in SST (between factual and counterfactual simulations) is shown to be related to the generalised extreme value (GEV) location parameter and consequently the RR, especially for return periods of less than 50 years. It is suggested that a suitable range of SST patterns are used for future attribution studies to ensure that this source of uncertainty is represented within the simulations and subsequent attribution results. It is shown that the risk change between factual and counterfactual simulations is not purely a simple shift in the distribution (i.e. change in GEV location parameter). For return periods greater than 50 years, the GEV shape parameter is found to strongly influence the RR determined with the GEV scale parameter affecting only the most severe events.

Satellite Observations of Enhanced Chlorophyll Variability in the Southern California Bight

AbstractSatellite observations from the Moderate Resolution Imaging Spectroradiometer and Sea‐viewing Wide Field‐of‐view Sensor reveal a “tongue” of elevated near‐surface chlorophyll that extends into the Southern California Bight from Point Conception. A local chlorophyll maximum at the western edge of the bight, near the Santa Rosa Ridge, indicates that the chlorophyll is not solely due to advection from Point Conception but is enhanced by local upwelling. Chlorophyll in the bight peaks in May and June, in phase with the seasonal cycle of wind stress curl. The spatial structure and seasonal variability suggest that the local chlorophyll maximum is due to a combination of bathymetric influence from the Santa Rosa Ridge and orographic influence from the coastline bend at Point Conception, which causes sharp wind stress curl in the bight. High‐resolution glider observations show thermocline doming in May–June, in support of the local upwelling effect. Despite the evidence for local wind stress curl‐forced upwelling in the bight, we cannot rule out alternative mechanisms for the local chlorophyll maximum, such as iron supply from the ridge. Covariability between chlorophyll, surface wind stress, and sea surface temperature (SST) indicates that nonseasonal chlorophyll variability in the bight is closely related to SST, but the spatial patterns of SST influence vary by time scale: Subannual chlorophyll variability is linked to local wind‐forced upwelling, while interannual chlorophyll variability is linked to large‐scale SST variations over the northeast Pacific. This suggests a greater role for nonlocal processes in the bight's low‐frequency chlorophyll variability.

Relationships between pacific and atlantic ocean sea surface temperatures and water levels from satellite altimetry data in the Amazon rivers

ABSTRACT The influence of SST (Sea Surface Temperature) of adjacent oceans on the variability of water levels in the Amazon basin was investigated by using radar altimetry from the ENVISAT and Jason-2 missions. Data from the in situ network was used to compare the correlations of water level and SST anomalies in the sub-basins of the Amazonas-Peru, Solimões, Negro and Madeira Rivers. The analysis was made on the monthly and annual scales between 2003 and 2015. The correlations with anomalies of levels from altimetry presented higher accuracy indices than those from the conventional network. In general, ATN and PAC are better correlated with the entire basin. During the flood months, most of the sub-basins presented negative associations with ATN. In the months of ebb, the response to the indexes varies according to the region. The satellite altimetry data permitted to reach regions non-monitored by the conventional network. We also analyzed the impacts of hydrological extremes in all these sub-regions in the last 13 years. In Western Amazon, the drought of 2010 stands out, associated with the warming of the Tropical Atlantic and the El Niño. In the Negro River, the water level anomalies were the lowest in the basin during the 2005 drought. In the Purus River, the effects of the 2010 drought that affected the entire Amazon, were higher in 2011 due to its strong relationship with the Atlântic and Pacific oceans. In general, hydrological extremes are stronger or highlighted when SST increases simultaneously in both oceans.

The impact of SST on the wind and air temperature simulations: a case study for the coastal region of the Rio de Janeiro state

The impact of Sea Surface Temperature (SST) on the wind and air temperature numerical simulations over the coastal region of the state of Rio de Janeiro, Brazil, was investigated using the Weather Research and Forecasting (WRF) model. The study period comprised January 24–26, 2014, characterized by the occurrence of coastal upwelling. Two numerical experiments were performed. The first, called EGFS, used the Global Forecast System (GFS) results to prescribe the initial and boundary conditions. In the second, called EMUR, the SST was replaced by the Multi-scale Ultra-high-Resolution SST (MUR SST). The experiments showed significant differences between the SST fields, being higher than 10 °C. Through the comparison with observations, we verified that the upwelling was better represented in the EMUR, which consequently generated improvements in the temperature at 2 m above ground level (AGL) over this region. In the offshore region, over areas with higher SST, the wind speed at 10 m AGL was stronger, and opposite behavior was observed over low SST areas. In addition, in regions with higher SST differences between the experiments, differences of wind direction at 10 m AGL higher than 90° were detected. The SST influence on the air temperature and wind speed profiles was significant up to 300 and 900 m, respectively. The comparisons between the wind observations with the numerical results show that the land–sea breeze simulation (thermal forced) was underestimated in relation to the synoptic forcing (South Atlantic Subtropical Anticyclone), even with significant SST differences between experiments.

Influence of Springtime Atlantic SST on ENSO: Role of the Madden–Julian Oscillation

Increased evidence has shown the important role of Atlantic sea surface temperature (SST) in modulating the El Nino–Southern Oscillation (ENSO). Persistent anomalies of summer Madden–Julian Oscillation (MJO) act to link the Atlantic SST anomalies (SSTAs) to ENSO. The Atlantic SSTAs are strongly correlated with the persistent anomalies of summer MJO, and possibly affect MJO in two major ways. One is that an anomalous cyclonic (anticyclonic) circulation appears over the tropical Atlantic Ocean associated with positive (negative) SSTA in spring, and it intensifies (weakens) the Walker circulation. Equatorial updraft anomaly then appears over the Indian Ocean and the eastern Pacific Ocean, intensifying MJO activity over these regions. The other involves a high pressure (low pressure) anomaly associated with the North Atlantic SSTA tripole pattern that is transmitted to the mid- and low-latitudes by a circumglobal teleconnection pattern, leading to strong (weak) convective activity of MJO over the Indian Ocean. The above results offer new viewpoints about the process from springtime Atlantic SSTA signals to summertime atmospheric oscillation, and then to the MJO of tropical atmosphere affecting wintertime Pacific ENSO events, which connects different oceans.

Will the California Current lose its nesting Tufted Puffins?

Tufted Puffin (Fratercula cirrhata) populations have experienced dramatic declines since the mid-19th century along the southern portion of the species range, leading citizen groups to petition the United States Fish and Wildlife Service (USFWS) to list the species as endangered in the contiguous US. While there remains no consensus on the mechanisms driving these trends, population decreases in the California Current Large Marine Ecosystem suggest climate-related factors, and in particular the indirect influence of sea-surface temperature on puffin prey. Here, we use three species distribution models (SDMs) to evaluate projected shifts in habitat suitable for Tufted Puffin nesting for the year 2050 under two future Intergovernmental Panel on Climate Change (IPCC) emission scenarios. Ensemble model results indicate warming marine and terrestrial temperatures play a key role in the loss of suitable Tufted Puffin nesting conditions in the California Current under both business-as-usual (RCP 8.5) and moderated (RCP 4.5) carbon emission scenarios, and in particular, that mean summer sea-surface temperatures greater than 15 °C are likely to make habitat unsuitable for breeding. Under both emission scenarios, ensemble model results suggest that more than 92% of currently suitable nesting habitat in the California Current is likely to become unsuitable. Moreover, the models suggest a net loss of greater than 21% of suitable nesting sites throughout the entire North American range of the Tufted Puffin, regardless of emission-reduction strategies. These model results highlight continued Tufted Puffin declines—particularly among southern breeding colonies—and indicate a significant risk of near-term extirpation in the California Current Large Marine Ecosystem.

The influence of sea surface temperature on the intensity and associated storm surge of tropical cyclone Yasi: a sensitivity study

Abstract. Tropical cyclones (TCs) result in widespread damage associated with strong winds, heavy rainfall and storm surge. TC Yasi was one of the most powerful TCs to impact the Queensland coast since records began. Prior to Yasi, the SSTs in the Coral Sea were higher than average by 1–2 ∘C, primarily due to the 2010/2011 La Niña event. In this study, a conceptually simple idealised sensitivity analysis is performed using a high-resolution regional model to gain insight into the influence of SST on the track, size, intensity and associated rainfall of TC Yasi. A set of nine simulations with uniform SST anomalies of between −4 and 4 ∘C applied to the observed SSTs are analysed. The resulting surface winds and pressure are used to force a barotropic storm surge model to examine the influence of SST on the associated storm surge of TC Yasi. An increase in SST results in an increase in intensity, precipitation and integrated kinetic energy of the storm; however, there is little influence on track prior to landfall. In addition to an increase in precipitation, there is a change in the spatial distribution of precipitation as the SST increases. Decreases in SSTs result in an increase in the radius of maximum winds due to an increase in the asymmetry of the storm, although the radius of gale-force winds decreases. These changes in the TC characteristics also lead to changes in the associated storm surge. Generally, cooler (warmer) SSTs lead to reduced (enhanced) maximum storm surges. However, the increase in surge reaches a maximum with an increase in SST of 2 ∘C. Any further increase in SST does not affect the maximum surge but the total area and duration of the simulated surge increases with increasing upper ocean temperatures. A large decrease in maximum storm surge height occurs when a negative SST anomaly is applied, suggesting if TC Yasi had occurred during non-La Niña conditions the associated storm surge may have been greatly diminished, with a decrease in storm surge height of over 3 m when the SST is reduced by 2 ∘C. In summary, increases in SST lead to an increase in the potential destructiveness of TCs with regard to intensity, precipitation and storm surge, although this relationship is not linear.

Regional-scale surface temperature variability allows prediction of Pacific bluefin tuna recruitment

AbstractFuture sustainable management of fisheries will require resilience to the effects of environmental variability and climate change on stock productivity. In this study, we examined relationships between sea surface temperature (SST) in the region between Taiwan and the Sea of Japan, and annual recruitment of Pacific bluefin tuna (Thunnus orientalis: PBF) over the past 35 years. Spatial correlation maps showed that warmer SSTs south of Shikoku, in the East China Sea and in the Sea of Japan from summer to late fall were associated with above average recruitment. SST anomalies near larval and juvenile habitats were most strongly correlated with local air temperatures. Generalized Additive Models predicting annual PBF recruitment from SST fields suggested that the influence of SST on recruitment was stronger than that of spawning stock biomass. Correlations between SST and recruitment likely reflect biological processes relevant to early juvenile habitat suitability. The influence of late fall SSTs could also be a result of varying availability of age-0 fish to the troll fishery; however, the relative importance of these processes was not clear. Despite these knowledge gaps, the strong predictive power of SST on PBF recruitment can allow more proactive management of this species under varying environmental conditions.

Amazon drought and forest response: Largely reduced forest photosynthesis but slightly increased canopy greenness during the extreme drought of 2015/2016.

Amazon droughts have impacted regional ecosystem functioning as well as global carbon cycling. The severe dry-season droughts in 2005 and 2010, driven by Atlantic sea surface temperature (SST) anomaly, have been widely investigated in terms of drought severity and impacts on ecosystems. Although the influence of Pacific SST anomaly on wet-season precipitation has been well recognized, it remains uncertain to what extent the droughts driven by Pacific SST anomaly could affect forest greenness and photosynthesis in the Amazon. Here, we examined the monthly and annual dynamics of forest greenness and photosynthetic capacity when Amazon ecosystems experienced an extreme drought in 2015/2016 driven by a strong El Niño event. We found that the drought during August 2015-July 2016 was one of the two most severe meteorological droughts since 1901. Due to the enhanced solar radiation during this drought, overall forest greenness showed a small increase, and 21.6% of forests even greened up (greenness index anomaly ≥1 standard deviation). In contrast, solar-induced chlorophyll fluorescence (SIF), an indicator of vegetation photosynthetic capacity, showed a significant decrease. Responses of forest greenness and photosynthesis decoupled during this drought, indicating that forest photosynthesis could still be suppressed regardless of the variation in canopy greenness. If future El Niño frequency increases as projected by earth system models, droughts would result in persistent reduction in Amazon forest productivity, substantial changes in tree composition, and considerable carbon emissions from Amazon.