North Atlantic Sea Surface Temperature Research Articles

Subseasonal Prediction of Central European Summer Heatwaves with Linear and Random Forest Machine Learning Models

Abstract Heatwaves are extreme near-surface temperature events that can have substantial impacts on ecosystems and society. Early warning systems help to reduce these impacts by helping communities prepare for hazardous climate-related events. However, state-of-the-art prediction systems can often not make accurate forecasts of heatwaves more than two weeks in advance, which are required for advance warnings. We therefore investigate the potential of statistical and machine learning methods to understand and predict central European summer heatwaves on time scales of several weeks. As a first step, we identify the most important regional atmospheric and surface predictors based on previous studies and supported by a correlation analysis: 2-m air temperature, 500-hPa geopotential, precipitation, and soil moisture in central Europe, as well as Mediterranean and North Atlantic sea surface temperatures, and the North Atlantic jet stream. Based on these predictors, we apply machine learning methods to forecast two targets: summer temperature anomalies and the probability of heatwaves for 1–6 weeks lead time at weekly resolution. For each of these two target variables, we use both a linear and a random forest model. The performance of these statistical models decays with lead time, as expected, but outperforms persistence and climatology at all lead times. For lead times longer than two weeks, our machine learning models compete with the ensemble mean of the European Centre for Medium-Range Weather Forecast’s hindcast system. We thus show that machine learning can help improve subseasonal forecasts of summer temperature anomalies and heatwaves. Significance Statement Heatwaves (prolonged extremely warm temperatures) cause thousands of fatalities worldwide each year. These damaging events are becoming even more severe with climate change. This study aims to improve advance predictions of summer heatwaves in central Europe by using statistical and machine learning methods. Machine learning models are shown to compete with conventional physics-based models for forecasting heatwaves more than two weeks in advance. These early warnings can be used to activate effective and timely response plans targeting vulnerable communities and regions, thereby reducing the damage caused by heatwaves.

Extreme heatwave over Eastern China in summer 2022: the role of three oceans and local soil moisture feedback

Eastern China experienced persistent regional extreme heatwaves in the summer of 2022, with disparate spatial features and formation mechanisms in different months. We quantitatively assessed the relative contributions of three oceans, i.e. tropical Indian Ocean and Pacific and North Atlantic, and the local soil moisture–temperature feedback using linear regression. The results showed that the monthly mean atmospheric circulation anomalies failed to explain the extreme heatwave in June 2022. The combined contribution of the tropical Indo-Pacific and North Atlantic sea surface temperature anomalies (SSTAs), together with the local soil moisture–temperature feedback, explaining approximately 10% of the temperature anomalies. In July, the tropical Indo-Pacific SSTAs promoted anomalous atmospheric circulation and extreme heat via meridional circulation originating in the Maritime Continent, accounting for approximately 10% of the temperature anomalies, with North Atlantic SSTAs contributing the same percentage by a mid-latitude steady Rossby wave. Local soil moisture–temperature feedback accounted for 42% of the anomalies. The tropical Indo-Pacific SSTAs produced a strong western North Pacific anticyclone in August, but their direct contribution to the temperature anomalies was negligible. The North Atlantic SSTAs contributed 9% of the total via the mid-latitude steady Rossby wave. Local soil moisture–temperature feedback contributed 66%, suggesting that the July heatwave and drought exerted a significant impact on the subsequent August extreme heatwave. Global warming has greatly facilitated extreme heatwaves, accounting for about 30%–40% of these events in summer 2022. These results also suggest that the climatic effects of tropical Indo-Pacific and North Atlantic SSTAs on Eastern China are evident in the month-to-month variation in summer. Our results thus contribute to the understanding and prediction of extreme heatwaves in Eastern China.

Evaluation on the Forecast Skills of Precipitation and Its Influencing Factors in the Flood Season in Liaoning Province of China

To clarify the precipitation forecast skills of climate forecast operations in the flood season in Liaoning Province of China, this study examines the forecast accuracies of China’s national and provincial operational climate prediction products and the self-developed objective prediction methods and climate model products by Shenyang Regional Climate Center (SRCC) in the flood season in Liaoning. Furthermore, the forecast accuracies of the main influencing factors on the precipitation in the flood season of Liaoning are assessed. The results show that the SRCC objective methods have a relatively high accuracy. The European Centre for Medium-Range Weather Forecasts (ECMWF) sub-seasonal forecast initialized at the sub-nearest time has the best performance in June. The National Climate Center (NCC) Climate System Model sub-seasonal forecast initialized at the sub-nearest time, and the ECMWF seasonal and sub-seasonal forecasts initialized at the nearest time, perform the best in July. The NCC sub-seasonal forecast initialized at the sub-nearest time has the best performance in August. For the accuracy of the SRCC objective method, the more significant the equatorial Middle East Pacific sea surface temperature (SST) anomaly is, the higher the evaluation score of the dynamic–analogue correction method is. The more significant the North Atlantic SST tripole is, the higher the score of the hybrid downscaling method is. For the forecast accuracy of the main influencing factors of precipitation, the tropical Atlantic SST and the north–south anti-phase SST in the northwest Pacific can well predict the locations of the southern vortex and the northern vortex in early summer, respectively. The warm (clod) SST in China offshore has a good forecast performance on the weak (strong) southerly wind in midsummer in Northeast China. The accuracy of using the SST in the Nino 1+2 areas to predict the north–south location of the western Pacific subtropical high is better than that of using Kuroshio SST. The accuracy of predicting northward-moving typhoons from July to September by using the SST in the west-wind-drift area is better than using the SST in the Nino 3 area. The above conclusions are of great significance for improving the short-term climate prediction in Liaoning.

Manifestation of the Early 20th Century Warming in the East-European Plain: Atmospheric Circulation Anomalies and Its Connection to the North Atlantic SST and Sea Ice Variability

A study of the climatic characteristics and annual runoff of the Volga and Severnaya Dvina rivers demonstrates that, on the East European Plain (EEP), Early Twentieth Century Warming (ETCW) manifested in a multiyear drought between 1934 and 1940; this drought has no analogues in this region in terms of intensity and duration according to Palmer’s classification, and caused extreme hydrological events. The circulation conditions during this event were characterized by an extensive anticyclone over Eastern Europe, combined with a cyclonic anomaly in the circumpolar region. An analysis of the spatial features of sea surface temperature (SST) anomalies indicate that the surface air temperature (SAT) anomalies in July on the EEP during ETCW were related not only to the North Atlantic (NA) warming and positive AMO phase, but also to a certain spatial pattern of SST anomalies characteristic of the 1920–1950 period. The difference between the SST anomalies of the opposite sign in the different NA zones, used as the indicator of the obtained spatial pattern, shows the quite close relations between the July SAT anomalies on the EEP and the atmospheric circulation patterns responsible for them. The positive phase of the Atlantic Multidecadal Oscillation (AMO) and the expansion of the subtropical high-pressure belt to the north and to the east can be considered as global-scale drivers of this phenomenon. The AMO also impacts the sea ice cover in the Barents–Kara Sea region, which, in turn, could have led to specific atmospheric circulation patterns and contributed to droughts on the EEP in the 1930s.

Impacts of autumn-winter Central Asian snow cover on the interannual variation in Northeast Asian winter precipitation

The current work investigated the impact of the interannual variation in the autumn-winter snow cover extent (SCE) over the extratropical Eurasian continent on Northeast Asian winter precipitation (NAWP) using observational data from 1972 to 2019. The leading singular value decomposition (SVD) mode of the interannual variation in the NAWP is significantly related to autumn SCE anomalies over Central Asia (SCE_CA), with decreased autumn SCE_CA corresponding to increased NAWP. The possible mechanisms responsible for this autumn SCE_CA-NAWP relationship are examined. The analytical results show that the reduced autumn SCE_CA has a significant warming effect on the overlying atmosphere and induces an anomalous anticyclone over CA. This anticyclonic response cooperates with the North Atlantic sea surface temperature anomaly (SST)-generated atmospheric wave pattern, promoting a further eastward extension of the wave pattern to the downstream regions of the Eurasian continent. The anomalous autumn SCE_CA can persist to the following winter, and its related atmospheric wave train is maintained and further strengthened by the increased winter SCE over North China (SCE_NC). In winter, the atmospheric circulation features a pronounced low-pressure system over Northeast Asia and a high-pressure system over the western North Pacific sector. The anomalous southeasterly winds between these two systems transport water vapor from the lower-latitude Pacific Ocean to the interior of the continent, accounting for more NAWP. A composite analysis further indicates that this autumn SCE_CA-NAWP relationship is primarily independent of the North Atlantic SSTs.

A Physics‐Based Empirical Model for the Seasonal Prediction of the Central China July Precipitation

AbstractJuly is the rainy peak month of central China, with a large interannual variation of local precipitation often causing serious droughts and floods. The seasonal prediction of the central China July precipitation (CCJP) is an important but still challenging task. Here, we suggest several robust seasonal predictors for the CCJP, including the preceding winter intensity of El Niño‐South Oscillation (ENSO), the winter‐to‐spring decaying rate of ENSO signals in the central Pacific, as well as the spring tropical and subpolar North Atlantic sea surface temperature anomalies. A physics‐based empirical model is then developed to predict the CCJP by using the principal component regression of the aforementioned seasonal predictors. In our statistical model, the seasonal prediction skill of the CCJP is high, with the cross‐validated reforecast skill at 0.81 during 1993–2021. This suggests a skillful seasonal prediction of the CCJP, with potentially enormous benefits for the local society and economy.

Correction to: Impacts of the strengthened Atlantic meridional overturning circulation on the North Atlantic sea surface temperature: mean state

Correction to: Impacts of the strengthened Atlantic meridional overturning circulation on the North Atlantic sea surface temperature: mean state

Spring Regional Sea Surface Temperatures as a Precursor of European Summer Heatwaves

AbstractDifferent spring and early summer North Atlantic sea surface temperature anomalies (SSTAs) have been shown to precede recent European summer heatwaves (EuSHWs). So far, the limited number of observed events associated with several physical mechanisms has prevented a robust identification of SSTAs as precursors. Here, we extend beyond previous studies by combining 100 historical simulations (1850–2005) of the MPI Grand‐Ensemble with an explainable neural‐network method. We find that the spring tripolar North Atlantic pattern with positive SSTAs in the Subtropical Gyre is a precursor of EuSHWs. In addition, positive SSTAs west of the Iberian Peninsula, and in the North Sea, the Baltic Sea and the Mediterranean Sea relate to distinct early summer soil moisture anomaly patterns and are precursors of western and southeastern EuSHWs, respectively. While the phase of the tripolar North Atlantic pattern indicates whether a EuSHW might emerge, regional SSTAs indicate the spatial characteristics of EuSHWs.

Tropical Pacific and North Atlantic Sea Surface Temperature Patterns Modulate Mississippi Basin Hydroclimate Extremes Over the Last Millennium

AbstractMississippi River basin floods impart large socioeconomic impacts over the central United States. Improving flood predictability depends on our understanding of the dynamical controls on Mississippi basin hydroclimate. However, short instrumental records make it difficult to constrain the connections between flooding and climate variability. Here, we use the Paleo Hydrodynamics Data Assimilation product, spanning the Last Millennium, to investigate the impacts of tropical Pacific and North Atlantic sea surface temperature (SST) variability on hydrological extremes across the Mississippi River and its major tributaries. Wet extremes are associated with strong El Niño‐like warming over the tropical Pacific, but specific SST patterns matter: dry (wet) conditions occur during Central Pacific (Eastern Pacific) El Niño events. The influence of North Atlantic SSTs is less clear, but cool SSTs contribute to Ohio basin wet extremes. These results are relevant for seasonal‐to‐interannual flood hazard prediction on the fourth largest river basin in the world.

Unraveling the mechanisms and implications of a stronger mid-Pliocene Atlantic Meridional Overturning Circulation (AMOC) in PlioMIP2

Abstract. The mid-Pliocene warm period (3.264–3.025 Ma) is the most recent geological period in which the atmospheric CO2 concentration was approximately equal to the concentration we measure today (ca. 400 ppm). Sea surface temperature (SST) proxies indicate above-average warming over the North Atlantic in the mid-Pliocene with respect to the pre-industrial period, which may be linked to an intensified Atlantic Meridional Overturning Circulation (AMOC). Earlier results from the Pliocene Model Intercomparison Project Phase 2 (PlioMIP2) show that the ensemble simulates a stronger AMOC in the mid-Pliocene than in the pre-industrial. However, no consistent relationship between the stronger mid-Pliocene AMOC and either the Atlantic northward ocean heat transport (OHT) or average North Atlantic SSTs has been found. In this study, we look further into the drivers and consequences of a stronger AMOC in mid-Pliocene compared to pre-industrial simulations in PlioMIP2. We find that all model simulations with a closed Bering Strait and Canadian Archipelago show reduced freshwater transport from the Arctic Ocean into the North Atlantic. This contributes to an increase in salinity in the subpolar North Atlantic and Labrador Sea that can be linked to the stronger AMOC in the mid-Pliocene. To investigate the dynamics behind the ensemble's variable response of the total Atlantic OHT to the stronger AMOC, we separate the Atlantic OHT into two components associated with either the overturning circulation or the wind-driven gyre circulation. While the ensemble mean of the overturning component is increased significantly in magnitude in the mid-Pliocene, it is partly compensated by a reduction in the gyre component in the northern subtropical gyre region. This indicates that the lack of relationship between the total OHT and AMOC is due to changes in OHT by the subtropical gyre. The overturning and gyre components should therefore be considered separately to gain a more complete understanding of the OHT response to a stronger mid-Pliocene AMOC. In addition, we show that the AMOC exerts a stronger influence on North Atlantic SSTs in the mid-Pliocene than in the pre-industrial, providing a possible explanation for the improved agreement of the PlioMIP2 ensemble mean SSTs with reconstructions in the North Atlantic.

A comparison of seasonal rainfall forecasts over Central America using dynamic and hybrid approaches from Copernicus Climate Change Service seasonal forecasting system and the North American Multimodel Ensemble

AbstractSeasonal rainfall forecasts provide information several months ahead to support decision making. These forecasts may use dynamic, statistical, or hybrid approaches, but their comparative value is not well understood over Central America. This study conducts a regional evaluation of seasonal rainfall forecasts focusing on two of the leading dynamic climate ensembles: the Copernicus Climate Change Service seasonal forecasting system (C3S) and the North American Multimodel Ensemble (NMME). We compare the multimodel ensemble mean and individual model predictions of seasonal rainfall over key wet season periods in Central America to better understand their relative forecast skill at the seasonal scale. Three types of rainfall forecasts are compared: direct dynamic rainfall predictions from the C3S and NMME ensembles, a statistical approach using the lagged observed sea surface temperature (SST), and an indirect hybrid approach, driving a statistical model with dynamic ensemble SST predictions. Results show that C3S and NMME exhibit similar regional variability with strong performance in the northern Pacific part of Central America and weaker skill primarily in eastern Nicaragua. In the northern Pacific part of the region, the models have high skill across the wet season. Indirect forecasts can outperform the direct rainfall forecasts in specific cases where the direct forecasts have lower predictive power (e.g., eastern Nicaragua during the early wet season). The indirect skill generally reflects the strength of SST associations with rainfall. The indirect forecasts based on Tropical North Atlantic SSTs are best in the early wet season and the indirect forecasts based on Niño3.4 SSTs are best in the late wet season when each SST zone has a stronger association with rainfall. Statistical predictions are competitive with the indirect and direct forecasts in multiple cases, especially in the late wet season, demonstrating how a variety of forecasting approaches can enhance seasonal forecasting.

КРУПНОМАСШТАБНЫЕ ЛЕТНИЕ ВОЛНЫ ТЕПЛА НА ЮГЕ ЕВРОПЕЙСКОЙ РОССИИ

For large-scale heat waves that occur in the south of the European part of Russia (EPR), the frequency variability since the beginning of the 20th century is considered, including variations on decadal scales and a trend during the global warming period, accompanying variations in the aridity index SPI, and the structure of the longest waves. The geographic distribution of air temperature anomalies on the territory of the Russian Federation, large-scale circulation conditions, the North Atlantic sea surface temperature (SST) anomalies, which accompanied heat waves in the south of the EPR, are analyzed using the composite analysis. In particular, the wave structure was revealed of the composite field of the air temperature anomaly for days with heat waves and the related 500 hPa geopotential height (H500) fields over Russia. The H500 field structure generally corresponds to the negative phase of the East Atlantic-Western Russia (EAWR) circulation pattern. Similar structures of the geopotential field are observed during heat waves in the northern half of the EPR. However, in this case, there are specific features that contribute to the inflow of cold air from the north to the southern regions. It is shown that the values of the EAWR index are significantly shifted towards negative values in the months when long heat waves occur over the southern EPR. The waves are accompanied by positive anomalies of the North Atlantic SST and the strongly increased blocking anticyclone activity. The downward trend in the EAWR index observed in recent decades and the SST rise expected with the global warming increase a risk of droughts in the main grain-producing region of the country.

Development and Assessment of Seasonal Rainfall Forecasting Models for the Bani and the Senegal Basins by Identifying the Best Predictive Teleconnection

The high variability of rainfall in the Sahel region causes droughts and floods that affect millions of people every year. Several rainfall forecasting models have been proposed, but the results still need to be improved. In this study, linear, polynomial, and exponential models are developed to forecast rainfall in the Bani and Senegal River basins. All three models use Atlantic sea surface temperature (SST). A fourth algorithm using stepwise regression was also developed for the precipitation estimates over these two basins. The stepwise regression algorithm uses SST with covariates, mean sea level pressure (MSLP), relative humidity (RHUM), and five El Niño indices. The explanatory variables SST, RHUM, and MSLP were selected based on principal component analysis (PCA) and cluster analysis to find the homogeneous region of the Atlantic with the greatest predictive ability. PERSIANN-CDR rainfall data were used as the dependent variable. Models were developed for each pixel of 0.25° × 0.25° spatial resolution. The second-order polynomial model with a lag of about 11 months outperforms all other models and explains 87% of the variance in precipitation over the two watersheds. Nash–Sutcliffe efficiency (NSE) values were between 0.751 and 0.926 for the Bani River basin and from 0.175 to 0.915 for the Senegal River basin, for which the lowest values are found in the driest area (Sahara). Results showed that the North Atlantic SST shows a more robust teleconnection with precipitation dynamics in both basins.

Assessing changes in size at maturity for the European hake (Merluccius merluccius) in Atlantic Iberian waters

European hake (Merluccius merluccius) is a commercially important resource in Iberian Atlantic waters. Despite the recovery plan implemented in 2006 and the multiannual management plan for western waters, fishing mortality is still higher than that corresponding to the maximum sustainable yield for the southern European hake stock. The biological processes underlying the dynamics of this stock and its life history traits are essential for assessing population productivity and resilience, making them basic information for management. We analysed the temporal variability of size at maturity (L50) of this species and the main factors influencing it in Atlantic Iberian waters from 1982 to 2019. The annual variability of L50 for each sex was modelled with generalized additive models, considering explanatory environmental variables (Atlantic Multidecadal Oscillation, North Atlantic Oscillation and sea surface temperature) and biological variables (biomass, spawning biomass at length and relative condition factor). The results showed that the L50 of males decreased by a total of 12.9 cm and L50 of females decreased by a total of 10.9 cm from 1982 to 2019. For females the significant explanatory variables were year, spawning biomass at length, biomass and the North Atlantic Oscillation, while for males only year was an explanatory variable. These results are important for understanding the status of the European hake population, signalling that L50 is a good indicator for predicting future population dynamics.

The Summertime Circulation Types over Eurasia and Their Connections with the North Atlantic Oscillation Modulated by North Atlantic SST

ERA5 monthly averaged reanalysis data during 1979–2020 are used to analyze the anomalous characteristics of summertime circulation types over Eurasia and their connections with the North Atlantic Oscillation (NAO) modulated by North Atlantic sea surface temperature (SST). A circulation index (CI) is defined to describe the anomalous characteristics of summertime circulation types over the Eurasian mid-high latitude and classify the anomalous circulation into a double-ridge type (DR-type) and double-trough type (DT-type). The results show that these anomalous circulation types are closely related to the variation of the western Pacific subtropical high (WPSH), East Asian subtropical jet (EASJ), South Asia high (SAH) and summer precipitation anomalies in China. There is a significant negative correlation between summer NAO and circulation types over Eurasia. The positive CI is favorable for the southward movement of the EASJ and two positive height anomalies over the Ural Mountains and the Sea of Okhotsk, respectively. Accompanied by moisture convergence and a strong ascending motion over the middle and lower reaches of the Yangtze River Valley (MLYRV), the summer rainfall will be above normal. These patterns are reversed in positive NAO-index years. The connection between the NAO and circulation types over Eurasia is modulated by a tri-pole SST anomaly pattern over the North Atlantic, which may induce the NAO-like atmospheric circulation and strengthen the impacts of the NAO on Eurasian circulation types. A wave train from the North Atlantic to East Asia, which is aroused by the tri-pole SST anomaly pattern, is the potential mechanism for linking summer NAO and circulation types over Eurasia.

Impacts of the strengthened Atlantic meridional overturning circulation on the North Atlantic sea surface temperature: mean state

Impacts of the strengthened Atlantic meridional overturning circulation on the North Atlantic sea surface temperature: mean state

Persistence or Transition of the North Atlantic Oscillation Across Boreal Winter: Role of the North Atlantic Air‐Sea Coupling

AbstractClimate anomalies over North America and Europe are closely related to the North Atlantic Oscillation (NAO). The persistence, decay or switch of the NAO phase across the boreal winter determines whether the NAO‐related climate anomalies are sustained, weakened or reversed during the boreal winter. This study compares the spatiotemporal evolution of atmospheric wind and sea surface temperature (SST) anomalies over the North Atlantic corresponding to persistence and switch of the NAO phase across the boreal winter. It is revealed that the persistence of the NAO from early to late winter is associated with a strong coupling between the NAO and the North Atlantic tripole SST anomalies. The formation of the tripole SST anomalies is attributed to the wind‐related surface latent heat flux changes. The tripole SST anomalies feedback on the NAO through eddy‐mean flow interaction. In contrast, during the winters with the switch of the NAO phase, the North Atlantic SST anomalies follow the wind changes, but do not have obvious feedback on the NAO. Our analysis identifies a prominent change of the winter NAO evolution in the early 1990s. The NAO switches its phase from early to late winter during 1970s through the early 1990s, but tends to maintain its phase during the boreal winter after the early 1990s. This interdecadal change appears to be related to the mean SST change. The SST increase in both the tropical and mid‐latitude North Atlantic Ocean in the early 1990s enhances the feedback of the NAO‐induced tripole SST anomalies on the NAO.

Multiproxy Reconstruction of Pliocene North Atlantic Sea Surface Temperatures and Implications for Rainfall in North Africa

AbstractWetter conditions in the African Sahel during the Pliocene (5.3–2.6 Ma) likely played an important role in hominid evolution and may be explained by warm North Atlantic sea‐surface temperatures (SSTs), similar to the modern warm phase of the Atlantic multidecadal oscillation (AMO). We reconstruct Pliocene North Atlantic (2°S to 60°N) SSTs through a multiproxy reduced‐dimension methodology that combines two new foraminiferal (Trilobatus sacculifer) Mg/Ca‐based SST records from Ocean Drilling Program sites in the northwestern Atlantic (Site 997) and Gulf of Mexico (Site 625) with previously published multi‐proxy SST records from seven additional Atlantic sites. Our Pliocene reconstructions indicate that the North Atlantic was overall warmer than the comparison period (0–0.5 Ma) with the most extreme warming occurring in the tropical and eastern subtropical North Atlantic and in the Labrador Sea. Furthermore, the mean state of North Atlantic warming at 5 Ma resembles that of the modern warm phase of the AMO with average SST anomalies of 3.8°C ± 0.5°C in the AMO region. With that reconstructed index, along with reconstructed El Niño‐like eastern Tropical Pacific SSTs from our previous research, we reconstruct rainfall over the Pliocene North Africa, covering the Sahara‐Sahel region and the Megalake Chad Basin and find up to twice the rainfall of that today. We surmise that this increased precipitation rate, along with other aiding land and sub‐surface processes, sustained Megalake Chad.

Colpophyllia natans From Tobago, a Novel Paleoclimate Archive for Reconstructing Sea Surface Temperature in the Tropical Atlantic

AbstractMassive, long‐lived Siderastrea and Diploria corals are species commonly used for sea surface temperature (SST) reconstructions in the North Atlantic. However, they are rarely found to exceed 200 years in age. Thus, it is imperative to continuously develop alternative taxa for paleoreconstructions. Colpophyllia natans, a highly populous tropical North Atlantic coral, are known to grow large colonies, potentially containing environmental records spanning several hundreds of years. However, its low density and complicated architecture poses a challenge in extracting climate signals from this coral. This study presents the first monthly‐resolved climate calibration of Colpophyllia natans and validates its utility as a new paleoarchive, relative to Siderastrea siderea. Linear regressions of monthly and interannual coral Sr/Ca with instrumental SST reveal robust, significant relationships (p < 0.05), indicating that microsampling along a single thecal wall of C. natans allowed for robust climate reconstructions. Additionally, both corals capture similar SST variations (t‐test, p ≥ 0.05), which allowed for the generation of a single, composite interspecies SST record that correlates with instrumental SST even more strongly (p < 0.0001) than the individual corals. Mean annual and boreal summer interspecies SST correlate significantly with North Atlantic SST indices (p < 0.05), demonstrating the ability to capture regional, long‐term SST trends in the North Atlantic. Spatial correlation maps of boreal winter interspecies SST to instrumental SST and geopotential height anomalies reveal coherent spatial patterns linked to the North Atlantic Oscillation. Our findings suggest that Colpophyllia natans has enormous potential as a new paleoclimate archive for reconstructing temporal and spatial SST variability in the tropical Atlantic.

An Integrated View of Organic Biomarker‐Based Sea Surface Temperature Changes in the Subarctic Pacific Since the Last Ice Age

AbstractThe phase relationships of sea surface temperature (SST) changes between the North Pacific and North Atlantic during deglacial millennial‐scale climate events have been of great interest. However, uncertainties remain partly due to the sparsity of deglacial SST records in the North Pacific. This study presents a new high‐resolution ‐SST record spanning the entire last deglaciation from core LV63‐41‐2 retrieved from the Northwestern Pacific off the Kamchatka Peninsula, which allows us to explore regional SST change patterns and associated driving mechanisms by compiling previously published SST data in the subarctic Pacific. The subarctic Pacific SST changes during the Bølling‐Allerød and Younger Dryas show in‐phase relationships in response to the North Atlantic SST variations, suggesting a dominant control of atmospheric teleconnections between both oceans. During Heinrich Stadial 1 (HS1) when the North Atlantic exhibited significant cooling, the subarctic Pacific SST developments are complex, showing gradual warming from the Last Glacial Maximum to HS1 in the Northwestern Pacific and cooling at the onset of HS1 in the Northeastern Pacific. We suggest that the inconsistent phase responses resulted from the combined effects of multiple processes, which involve an enhanced poleward advection of warm subtropical waters, cold meltwater inputs from the retreating Cordilleran Ice Sheet into the Northeastern Pacific, and a persistent La Niña‐like state in the tropical Pacific.