Sea Surface Temperature Trends Research Articles

Surface Temperature Pattern Scenarios Suggest Higher Warming Rates Than Current Projections

AbstractAtmosphere‐ocean general circulation models (AOGCMs) struggle to reproduce recently observed sea surface temperature (SST) trend patterns. Here, we quantify the relevance of this SST pattern uncertainty to global‐mean temperature projections through convolving Green's functions with SST pattern scenarios that differ from the ones AOGCMs produce by themselves. We find that future SST pattern uncertainty has a significant impact on projections, such as increasing total model uncertainty by 40% in a high‐emissions scenario by 2085. A reversal of the current cooling trend in the East Pacific over the next few decades could lead to a period of global‐mean warming with a 60% higher rate than currently projected. SST pattern uncertainty works through a destabilization of the shortwave cloud feedback to affect temperature projections. It is critical for climate change impact, adaptation, and mitigation assessments to incorporate this previously unaccounted for uncertainty until we trust the evolution of SST patterns in AOGCMs.

Impact of Sea Surface Temperature in the Extratropical Southern Indian Ocean on Antarctic Sea Ice in Austral Spring

Abstract The relationship between the seasonal Antarctic sea ice concentration (SIC) variability and the extratropical southern Indian Ocean (SIO) sea surface temperature (SST) is explored in this study. It is found that the Antarctic SIC in a wide band of the SIO, Ross Sea, and Weddell Sea is significantly related to an SIO dipole (SIOD) SST anomaly on the interannual time scale during austral spring. This relationship is linearly independent of the effects of El Niño–Southern Oscillation, the Indian Ocean dipole, and the Southern Hemisphere annular mode. The positive phase of the SIOD, with warm SST anomalies off of western Australia and cold SST anomalies centered around 60°E in high latitudes, stimulates a downstream wave train that induces large-scale cyclonic circulations over the SIO and the Ross and Weddell Seas. Subsequently, anomalous horizontal moisture advection causes water vapor divergence, changes the surface energy budget, and cools the underlying ocean, which leads to the increased SIC over the region in the SIO, Ross Sea, and Weddell Sea. This SIOD SST anomaly reached a record low during the austral spring of 2016 and promoted the prominent wave pattern at high latitudes, contributing to the dramatic decline of sea ice in the 2016 spring. In addition, the proportion of the SIC trend that is linearly congruent with the SIOD SST trend during austral spring is quantified. The results indicate that the trend in the SIOD SST may account for a significant component of the 1979–2014 SIC trend in the Ross Sea with the congruency peaking at 60%.

Paradigm shift in the onset phase of the Indian Summer Monsoon since 2000 and its potential connection to South Indian Ocean

The Indian Ocean basin has undergone significant changes over the past two decades, and this study examines major shifts in the onset characteristics of the Indian Summer Monsoon (ISM) in response to changes in the dynamical and thermodynamic conditions. A thermodynamic index shows that the post-2000 period witnesses an approximately 3-day earlier (May 27) onset of ISM than the pre-2000 period. In the absence of an abrupt and distinct change from the dry to the wet season, the post-2000 era can be distinguished by its early and longer onset process. The Subtropical Indian Ocean Dipole (SIOD) undergoes a phase change during its evolution, which weakens the Mascarene High (MH) and hence the pressure gradient. The weakening of the MH along with the heterogeneity in Sea Surface Temperature (SST) trends have led to a weaker meridional pressure gradient over the Indian monsoon domain, resulting in a weak onset of the ISM. Additionally, warming in the Arabian Sea starts earlier than expected. The prolonged duration of the Indian Summer Monsoon (ISM) onset process in the post-2000 era can be attributed to several factors. These include the broader ascending limb of the Hadley cell over the south equatorial Indian Ocean, reduced wind shear, and the early development of a warmer Arabian Sea prior to the onset of the monsoon.

Late Quaternary glacier advances in the Andes of Santiago, central Chile, and paleoclimatic implications

Andean mountain glaciers in central Chile are in a transitional zone between the seasonal influence of the mid-latitude westerlies and subtropical semiarid conditions to the north. Long-term glacial dynamics for these glaciers and their relationship with the paleoclimate during the late Quaternary are poorly known despite their relevancy. We estimate here the timing and extent of late Pleistocene–early Holocene glaciers in the Andes of Santiago (33°50′S) from geomorphological and geochronological analyses. Our observations evidence that a glacial stage occurred before the Last Glacial Maximum (ELGM) at the San Gabriel drift (1,300 m a.s.l.), dated as ∼46–36 ka. Glacial stages during the latest Pleistocene–early Holocene transition period, partially concomitant with the Antarctic Cold Reversal (ACR) and with the Younger Dryas (YD) chronozones, were identified and dated at La Engorda drift (2,450–2,570 m a.s.l.) at ∼15–10 ka. We propose that the San Gabriel drift represents a prolonged glacial advance driven by increased precipitation and cold conditions off central Chile during glacial times. In La Engorda drift, late glacial advances occurred associated with increased regional precipitation, in the context of a transition from humid to arid climate in central Chile, concomitantly with a general warming trend of sea surface temperatures offshore in the southeastern Pacific and with reduced austral summer insolation. The results support the sensitivity of the Andean mountain glaciers to precipitation and paleoclimate conditions, most possibly associated with periods of increased northward influence of the mid-latitude westerlies during glacial and late glacial times, in addition to the El Niño/Southern Oscillation (ENSO) impact since the mid-Holocene, driving late Quaternary glacier advances in central Chile. We estimate a maximum variation of ∼1,200 m in the position of the late Quaternary Equilibrium Line Altitude (ELA), inferred at ∼3,400 m and ∼3,600 m a.s.l. at the time of the San Gabriel and La Engorda drifts, respectively, with respect to its modern location close to 4,600 m a.s.l.

Separating internal and forced contributions to near term SST predictability in the CESM2-LE

An open question in the study of climate prediction is whether internal variability will continue to contribute to prediction skill in the coming decades, or whether predictable signals will be overwhelmed by rising temperatures driven by anthropogenic forcing. We design a neural network that is interpretable such that its predictions can be decomposed to examine the relative contributions of external forcing and internal variability to future regional sea surface temperature (SST) trend predictions in the near-term climate (2020–2050). We show that there is additional prediction skill to be garnered from internal variability in the Community Earth System Model version 2 Large Ensemble, even in a relatively high forcing future scenario. This predictability is especially apparent in the North Atlantic, North Pacific and Tropical Pacific Oceans as well as in the Southern Ocean. We further investigate how prediction skill covaries across the ocean and find three regions with distinct coherent prediction skill driven by internal variability. SST trend predictability is found to be associated with consistent patterns of decadal variability for the grid points within each region.

Aerosol processes perturb cloud trends over Bay of Bengal: observational evidence

Although, the aerosol-cloud interactions and its impact on daily to seasonal radiation/temperature has been well observed over South Asia in last two decade, the role of aerosol-cloud interactions on cloud occurrence trends (and surface temperature) is yet not evident. Here, evidence of aerosol-induced control on cloud occurrence trends over the Northern Bay of Bengal (NBOB) during the monsoon onset period is presented. In last 15 years, increased aerosol emissions over North India have led to an increase in aerosol loading at an elevated altitude of 1–3 km over the NBOB outflow region in monsoon onset period. This elevated aerosol loading induces increases the air temperature at 1–2 km altitude and stabilizes the lower troposphere over the region in recent years. The enhanced atmospheric stability in the region caused low-level cloud occurrences (below 3 km) to increase in recent years by ~20%, potentially contributing to the observed non-intuitive cooling trends in sea surface temperatures. These aerosol-cloud-climate observations emphasize the crucial need for improved aerosol representations in coupled ocean-atmosphere models for accurate predictions of climate change over South Asia.

Patterns and Trends in Chlorophyll‐a Concentration and Phytoplankton Phenology in the Biogeographical Regions of Southwestern Atlantic

AbstractThe Southwestern Atlantic Ocean (SWA), is considered one of the most productive areas of the world, with a high abundance of ecologically and economically important fish species. Yet, the biological responses of this complex region to climate variability are still uncertain. Here, using 24 years of satellite‐derived Chl‐a data, we classified the SWA into 9 spatially coherent regions based on the temporal variability of Chl‐a concentration, as revealed by SOM (Self‐Organizing Maps) analysis. These biogeographical regions were the basis of a regional trend analysis in phytoplankton biomass, phenological indices, and environmental forcing variations. A general positive trend in phytoplankton concentration was observed, especially in the highly productive areas of the northern shelf‐break, where phytoplankton biomass has increased at a rate of up to 0.42 ± 0.04 mg m−3 per decade. Significant positive trends in sea surface temperature were observed in 4 of the 9 regions (0.08–0.26 °C decade−1) and shoaling of the mixing layer depth in 5 of the 9 regions (−1.50 to −3.36 m decade−1). In addition to the generally positive trend in Chl‐a, the most conspicuous change in the phytoplankton temporal patterns in the SWA is a delay in the autumn bloom (between 15 ± 3 and 24 ± 6 days decade−1, depending on the region). The observed variations in phytoplankton phenology could be attributed to climate‐induced ocean warming and extended stratification period. Our results provided further evidence of the impact of climate change on these highly productive waters.

Reversal of decadal trend in West China autumn rainfall in the late 1990s and possible causes

As a complex regional weather and climate phenomenon in China, the highly variable West China autumn rainfall (WCAR) causes severe flooding and related disasters that can have major impacts on socioeconomic and environmental sustainability. This study investigated both the reversal of the decadal trend in the WCAR during 1961–2020 and the related atmospheric circulation and oceanic backgrounds. The results showed that the decadal trend in the WCAR underwent distinct reversal in the late 1990s, with a significant trend of decline (increase) before (after) this reversal, which was directly linked to variations in the large-scale Eurasian atmospheric circulation, local moisture transport and dynamic conditions, and sea surface temperature (SST) in the subtropical South Pacific. Further investigation indicated that reduced sea level pressure over Asia, an enhanced European blocking high, and a deepened Lake Balkhash trough during the latter period favored southward movement of high-latitude cold air into West China. Moreover, a stronger southerly flow in the southern West China was observed in the latter period, which tended to transport more moisture from low-latitude ocean areas. Northward displacement of the East Asian jet (EAJ) also played a strong dynamic role in the reversal of the WCAR trend. Additionally, the reversal of the decadal trend in WCAR might also be attributed to a change in the trend of SST in the subtropical South Pacific from warming to cooling in the late 1990s. This resulted in southward displacement of the EAJ, which generated an anomalous descent and reduction in the WCAR.

Seasonally-reversed trends in the subtropical Northwestern Pacific linked to asymmetric AMO influences

This study identifies seasonally-reversed trends in Kuroshio strength and sea surface temperatures (SSTs) within the western North Pacific (WNP) since the 1990s, specifically in the 22° N–28° N region. These trends are characterized by increases during summer and decreases during winter. The seasonally-reversed trends are a result of the asymmetric responses of the WNP to a shift towards the positive phase of the Atlantic multidecadal oscillation (AMO) around the same period. The positive AMO induces an anomalous descent over the North Pacific during summer, leading to the direct strengthening of the gyre. However, during winter, it triggers an anomalous descent over the tropical Pacific, which excites a poleward wavetrain impacting the WNP and causing gyre weakening. The associated responses of the East Asian monsoon and China Coastal Current contribute to the observed seasonally-reversed SST trends. It is noteworthy that the seasonally-reversed trends in gyre strength and SSTs are predominantly observed north of 20° N in the WNP. This limitation arises because the anomalous cyclone within the winter poleward wavetrain is located north of this latitude boundary. Specifically, the clearest trends in gyre strength are observed in the northern segment of the Kuroshio, while the manifestation of SST trends in the Taiwan Strait could potentially be attributed to the influence and enhancement of the East Asian monsoon and the China Coastal Current. Due to the limited length of observational data, statistical significance of some of the signals discussed is rather limited. A CESM1 pacemaker experiments is further conducted to confirm the asymmetric responses of the North Pacific to the AMO between the summer and winter seasons.

Sea surface temperature trends for Tampa Bay, West Florida Shelf and the deep Gulf of Mexico

Sea surface temperatures for Tampa Bay, the West Florida Continental Shelf (WFS) and the adjacent deep Gulf of Mexico are examined for trends. Data sets are from stations maintained by the Hillsborough County Environmental Protection Commission, buoys maintained by the University of South Florida Coastal Ocean Monitoring and Prediction System and the National Oceanic and Atmosphere Administration (NOAA) National Data Buoy Center, the Optimum Interpolation Sea Surface Temperature analyses by the NOAA National Centers for Environmental Information, and the Hadley Centre Sea Surface Temperature. These various data sets, each with different record lengths, require the consideration of trends both on the basis of record length and start time. Tampa Bay shows a warming trend, but with considerable inter-annual variability and start time bias resulting in a lack of statistical significance in more recent years. The WFS is also generally warming, and its inter-annual variability is largely controlled by the upwelling of cooler, deeper Gulf of Mexico water across the shelf break. The deep GOM shows statistically significant warming in most of the data except for the “gappy” records from buoys, both along the continental shelf and in the deep water. Trends in the Gulf of Mexico are mostly between 0.1 and 0.5 °C/decade, somewhat larger than the secular rise found globally, although within the range of the observed decadal variability.

Temperature and salinity trends in the northern limit of the Canary Current Upwelling System

Thermohaline time series are crucial for detecting and quantifying abiotic changes in the marine environment, and even more so in the present global change scenario. This is particularly relevant for the Ría the Vigo and its adjacent shelf, a highly productive ecosystem at the northern limit of the Canary Current Upwelling System (CanCUS). This study analyses a 34-year time series (1987–2020) of Conductivity-Temperature-Depth (CTD) casts, the longest series available to date in the region. Long-term trends, shifts, and seasonal variability of temperature and salinity were assessed and investigated in relation to regional meteorological variability and basin-scale atmospheric teleconnection indices. Generalized Additive Models (GAM) allowed us to determine that monthly thermohaline variability can be largely explained by regional meteo-climatic variability, mainly upwelling index and river discharge. Trends and shifts in some teleconnection patterns, especially the East Atlantic (EA) pattern, may also be related to both the shift in salinity in 2013 and its long-term decrease below 50 m depth. Despite the current global warming context, no statistically significant trend was observed for either the upwelling index or temperature. The spatial analysis of sea surface temperature trends suggests that our study area has been responding to climate change differently from other surrounding near-shore areas, as the Finisterre Cape or the southern Bay of Biscay. Overall, this study highlights the importance of long-term observations to elucidate the impact of climate change in the northern limit of the CanCUS and encourages caution when extrapolating conclusions from ecosystem studies on a regional scale.

Interannual variability of sea surface temperature at the polar latitudes of the Atlantic Ocean

The general regularities and regional differences in the interannual variability of the sea surface temperature in the polar latitudes of the Atlantic Ocean are revealed according to the OI SST reanalysis data for period 1982—2017. The reanalysis contains daily average sea surface temperature values at the nodes of a regular grid 0,25°×0,25°. In this work, areas where the ice concentration did not exceed
 90 % were analyzed. In both polar basins, the position of areas with a high level of sea surface temperature
 interannual variability qualitatively coincides with the position of intense currents. The maximum values of
 linear sea surface temperature trends are observed in areas of the maximum level of interannual variability,
 while the trends in long-term sea surface temperature variability in the Arctic and Antarctic are noticeably
 different. Significant positive sea surface temperature trends prevail in the Atlantic sector of the Arctic.
 Significant negative trends have been identified only off the northeastern coast of Greenland and north of the Arctic Current. The sea surface temperature decrease on a long-term scale in this area is associated with an increase of cold water transport by the East Greenland and Arctic currents, which are formed as a result
 of the intensive melting of Arctic ice observed in recent decades. In the Atlantic sector of the Antarctic, on the contrary, significant negative sea surface temperature trends prevail. In the Arctic, the maximum values of positive sea surface temperature trends are observed in August—September during the period of maximum warming of surface waters and minimum concentration of drifting ice. In the Antarctic, the maximum negative sea surface temperature trends in absolute value are observed from August to October, during the period of surface water cooling and maximum ice concentration.

A comprehensive satellite-based assessment across the Pacific Arctic Distributed Biological Observatory shows widespread late-season sea surface warming and sea ice declines with significant influences on primary productivity.

Massive declines in sea ice cover and widespread warming seawaters across the Pacific Arctic region over the past several decades have resulted in profound shifts in marine ecosystems that have cascaded throughout all trophic levels. The Distributed Biological Observatory (DBO) provides sampling infrastructure for a latitudinal gradient of biological "hotspot" regions across the Pacific Arctic region, with eight sites spanning the northern Bering, Chukchi, and Beaufort Seas. The purpose of this study is two-fold: (a) to provide an assessment of satellite-based environmental variables for the eight DBO sites (including sea surface temperature (SST), sea ice concentration, annual sea ice persistence and the timing of sea ice breakup/formation, chlorophyll-a concentrations, primary productivity, and photosynthetically available radiation (PAR)) as well as their trends across the 2003-2020 time period; and (b) to assess the importance of sea ice presence/open water for influencing primary productivity across the region and for the eight DBO sites in particular. While we observe significant trends in SST, sea ice, and chlorophyll-a/primary productivity throughout the year, the most significant and synoptic trends for the DBO sites have been those during late summer and autumn (warming SST during October/November, later shifts in the timing of sea ice formation, and increases in chlorophyll-a/primary productivity during August/September). Those DBO sites where significant increases in annual primary productivity over the 2003-2020 time period have been observed include DBO1 in the Bering Sea (37.7 g C/m2/year/decade), DBO3 in the Chukchi Sea (48.0 g C/m2/year/decade), and DBO8 in the Beaufort Sea (38.8 g C/m2/year/decade). The length of the open water season explains the variance of annual primary productivity most strongly for sites DBO3 (74%), DBO4 in the Chukchi Sea (79%), and DBO6 in the Beaufort Sea (78%), with DBO3 influenced most strongly with each day of additional increased open water (3.8 g C/m2/year per day). These synoptic satellite-based observations across the suite of DBO sites will provide the legacy groundwork necessary to track additional and inevitable future physical and biological change across the region in response to ongoing climate warming.

Short-Term Prediction of Global Sea Surface Temperature Using Deep Learning Networks

The trend of global Sea Surface Temperature (SST) has attracted widespread attention in several ocean-related fields such as global warming, marine environmental protection and marine biodiversity. Sea surface temperature is influenced by climate change; with the accumulation of data from ocean remote sensing observations year by year, many scholars have started to use deep learning methods for SST prediction. In this paper, we use a dynamic region partitioning approach to process ocean big data and design a framework applied to a global SST short-term prediction system. On the architecture of a Long Short-Term Memory (LSTM) network, two deep learning multi-region SST prediction models are proposed, which extract temporal and spatial information of SST by encoding, using feature transformation and decoding to predict future multi-step states. The models are tested using OISST data and the model performance is evaluated by different metrics. The proposed MR-EDLSTM model and MR-EDConvLSTM model obtained the best results for short-term prediction, with RMSE ranging from 0.2712 °C to 0.6487 °C and prediction accuracies ranging from 97.60% to 98.81% for ten consecutive days of prediction. The results show that the proposed MR-EDLSTM model has better prediction performance in coastal areas, while the MR-EDConvLSTM model performs better in predicting the sea area near the equator. In addition, the proposed deep learning model has a smaller RMSE compared to the forecasting system based on the ocean model, indicating that the deep learning method has certain advantages in predicting global SST.

Coral Sr‐U Thermometry Tracks Ocean Temperature and Reconciles Sr/Ca Discrepancies Caused by Rayleigh Fractionation

AbstractUnderstanding climate change at the spatiotemporal scales necessary to improve climate projections requires proxy records that complement sparse and often contradictory observational temperature data sets. Massive long‐lived corals have tremendous potential in this regard, continuously recording information about ocean conditions as they grow. Nevertheless, extracting accurate ocean temperatures from corals is challenging because factors other than temperature influence skeletal chemistry. Here, we tested the ability of the coral Sr‐U thermometer to accurately capture annual sea surface temperatures (SSTs) in the subtropical Atlantic, where year‐to‐year temperatures vary by ∼1°C. Using laser ablation inductively coupled plasma mass spectrometry (LA‐ICP‐MS), we generated sufficient U/Ca – Sr/Ca pairs from a slow‐growing (1−2 mm/yr) Siderastrea siderea coral to calculate annual Sr‐U values. With the fine‐scale spatial resolution attained using the laser, skeleton accreted during both fast and slow growing times of the year was represented in our sampling. The resulting 30‐year‐long Sr‐U record tracked the amplitude and timing of annual SST to within ±0.2°C of observations (r = −0.71), whereas the Sr/Ca record did not (r = 0.23). Furthermore, Sr‐U corrected for Sr/Ca offsets among adjacent skeletal elements approximately 1 mm apart. These offsets are equivalent to differences of 2–3°C if typical Sr/Ca–SST calibrations are applied. Our observations indicate that Sr‐U can accurately constrain decadal‐to‐multidecadal variability and secular SST trends in regions where this information is urgently needed.

Warming trends of southwestern Atlantic SST and the summer's warmest SST's impact on South American climate

AbstractSeveral atmospheric variables are directly influenced by oceanic conditions, mainly the sea surface temperature (SST). SST trends and variability over the southwestern Atlantic (SWA) have affected the South American climate, principally the monsoonal period (austral summer). This study analysed the SST trends over the SWA for all seasons. In addition, possible large‐scale triggers of the austral summer's warmest SST over the SWA and the straight impacts of these warmest SSTs on the South American climate were investigated. The results showed a significant positive SST trend of approximately 0.02°C·year−1 over the SWA for all seasons. Since 2000, positive SST anomalies have increased in frequency in all seasons, with the seven warmest summers occurring during the 2010s. The highest SST summers over the SWA have been related to four leading causes: (i) planetary waves triggered by warm anomalies over the subtropical South Pacific; (ii) an omega‐type blocking configuration over the South Atlantic; (iii) a Southern Annular Mode positive phase; and (iv) a strengthening of the Hadley Cell, responding to warm SST over tropical North Atlantic. They all reflected on intensification of the South Atlantic Subtropical High and the western boundary current, heating the SWA. The summer's warmest SST led to positive air temperature anomalies extending in almost all of eastern South America, with significantly highest temperatures over southeastern Brazil, northern Argentina and western Paraguay. Clouds decrease strengthen the incident shortwave in southeastern Brazil, warming the region. Significant reduction of cloudiness and precipitation indicate a low performance of the South Atlantic Convergence Zone. The comparison of the warmest summers in 1980s–1990s in the SWA ratified the role of SST intensification. In conclusion, the positive SST trends over the SWA are related to the summer's warmest SST after 2000s, causing heating and dryness in eastern South America, mainly over southeastern Brazil.

Assessment of long-term trends in chlorophyll-a and sea surface temperature in the Arabian Sea and their association with aerosols using remote sensing

Aerosols over the oceanic region significantly influence Earth's energy budget and climate change. Therefore, this study examines the spatiotemporal patterns of MODIS retrieved aerosol optical depth, sea surface temperature, Chlorophyll-a, Sea-WiFS retrieved aerosol optical depth, and MERRA-2 model dust mass concentrations over the Arabian Sea (4o N–26o N to 50o E−78o E) during the period 2002–2020. The effects of dust aerosols on phytoplankton blooms using the Mann-Kendall and Theil Sen-slope are also analyzed in this study. An increase in aerosol optical depth (AOD) was observed within the latitudes of (4o N–26o N). The AOD shows an increasing trend at 13.4% per year over the Arabian Sea (AS). The highest value of Chl-a (∼7 mgm−3) was observed along the coast of Pakistan, Iran, and Oman. Moreover, a negative correlation is found between AOD and sea surface temperature (SST) along the coast of Oman and Somalia, while a strong positive correlation (∼0.99) is observed between AOD and Chlorophyll-a (Chl-a) along the coasts of Oman and Somalia.

Changes to Sea Surface Temperatures and Vertical Wind Shear and Their Influence on Tropical Cyclone Activity in the Caribbean and the Main Developing Region

Sea surface temperatures and vertical wind shear are essential to tropical cyclone formation. TCs need warm SSTs and low shear for genesis. Increasing SSTs and decreasing VWS influences storm development. This work analyzes SST and VWS trends for the Caribbean, surrounding region, and the Atlantic hurricane main developing region from 1982–2020. Storm intensity increases significantly during this period. Annual and seasonal trends show that regional SSTs in the MDR are warming annually at 0.0219 °C yr−1 and, per season, 0.0280 °C yr−1. Simultaneously, VWS decreases during the late rainfall season, at 0.056 m/s yr−1 in the MDR and 0.0167 m/s yr−1 in the Caribbean and surrounding area. The Atlantic Warm Pool is expanding at 0.51 km2 per decade, increasing upper atmospheric winds and driving VWS changes. Correlations of large-area averages do not show significant relationships between TC intensity, frequency, and SSTs/VWS during the LRS. The observed changes appear to be associated with regional warming SSTs impacting TC changes. Plain Language Abstract: Tropical cyclone (TC) formation requires warm ocean waters and low wind shear. Changes to sea surface anomalies and wind shear influences are essential to understanding storm development and intensification. The ability to forecast storm changes is vital to human lives and livelihoods. This work analyzes sea surface temperatures (SSTs) and vertical wind shear (VWS) trends in the Caribbean, surrounding areas, and the Atlantic main developing region (MDR). We found increasing SSTs, decreasing wind shears, an expanding Atlantic Warm Pool (AWP), and increased storm intensity during the Atlantic hurricane season.

The shift of decadal trend in Middle East dust activities attributed to North Tropical Atlantic variability

The Middle East, as the world’s second-largest dust source region, has dust emissions that significantly impact numerous populated areas, extending from North America to South Asia. Over the past two decades, dust activity in the Middle East has exhibited pronounced variability, with a notable trend shift from positive to negative around 2010. The underlying cause of this trend shift remains elusive. In this study, we employ multi-source datasets and global climate model simulations to demonstrate that the variability of Middle East dust activities is closely tied to changes in North Tropical Atlantic (NTA) sea surface temperature (SST). Specifically, a warm NTA SST anomaly generates an anomalous regional zonal cell characterized by ascending air motion above the NTA and descending air surrounding the Middle East. The associated surface high pressures around the Middle East subsequently induce hot and dry conditions accompanied by intensified Shamal winds in the north, which are favorable for dust emission and transport. The shift in SST trends from positive to negative in the NTA around 2010 is therefore responsible for the observed dust trend shift in the Middle East. This mechanism holds vital implications for predicting decadal dust variability over the Middle East region and further the project of global environment.

Tropical coral reefs in Sri Lanka are threatened due to the fluctuation of seasonal and interannual sea surface temperature.

The thermal stress of oceans causes coral bleaching, which induces loss of life in coral reefs and makes them exposed to other threats which directly and indirectly affect millions of other species that inhabit the reef. However, studies focusing on how those thermal stresses affect Sri Lankan fringing reef ecosystems are scarce. Hence, the patterns of long-term and short-term fluctuations of sea surface temperature (SST) over the shallow reefs around the country were studied by separating them into different zones as the eastern coast (Passikudha, Kayankerni, Adukkuparu, Parrot Rock, and Pigeon Island), the southern coast (Beruwala Barbarian, Hikkaduwa, Unawatuna, Ahangama, Mirissa, Madiha, Polhena, and Devundara), and northern-northwestern coasts (Valiththoondal, Palk Bay, Mannar, Kalpitiya, Thalwila, and Uswatakeiyawa). The 1km Multiscale Ultrahigh Resolution (MUR) Level 4 SST dataset was used to analyze seasonal and interannual SST variability from 2005 to 2021. The data were correlated with the Indian Ocean Dipole (IOD), Ekman velocity, and wind stress curl. The annual, seasonal, and monthly variability of SST on different coasts is significantly different. Higher increasing trends of SST from 0.0324 to 0.0411 ℃/year are observed on different coasts, and most of the time higher positive anomalies are recorded after 2014. The First Inter Monsoon (IM-1) and the month of April are more critical since they reach the maximum SST, and the minimum is in the North West Monsoon (NWM) and January. Significant positive relationships are recorded between the Indian Ocean Dipole (IOD) index and the monthly average SST on different coasts, which was robust on the southern coast. Therefore, tropical coral reefs in Sri Lanka are severely threatened due elevation of SST by global warming and climate variability.