Increase In Sea Surface Temperature Research Articles

Interannual Variability and Long-Term Trends in Intensity of the Yellow Sea Cold Water Mass during 1993–2019

The Yellow Sea Cold Water Mass (YSCWM) is an important component of the hydrodynamic system and it significantly impacts the primary production of the Yellow Sea. This study investigated the difference in the interannual variability and long-term trends between the northern YSCWM (NYSCWM) and southern YSCWM (SYSCWM), and explored the main physical environmental factors that led to their inconsistency using multiple wavelet coherence. On the interannual scale, the intensities of the NYSCWM and SYSCWM exhibited consistent variability, but the intensity of the SYSCWM had a larger standard deviation and longer periodic signal than that of the NYSCWM. The two-factor combination of surface air temperature (SAT)–Niño 3.4 in the NYSCWM and sea surface temperature (SST)–northward seawater velocity (Vgos) in the SYSCWM controlled the interannual variability, which meant the influencing intensity variability differed in the NYSCWM and SYSCWM. In the long-term trend, the intensities of the NYSCWM and SYSCWM both showed decreasing trends during the study period. However, the enhanced circulation provided more horizontal heat input into the SYSCWM, and the relatively higher increase in SST and decrease in the amplitude of variation in the thermocline depth promoted vertical heat exchange in the SYSCWM, thereby making the intensity of the SYSCWM decrease more quickly than that of the NYSCWM. These findings provide important references that facilitate a deeper understanding of the influence of hydrological processes on marine ecosystems in marginal seas.

Reflections on the impact and response to the Peruvian 2017 Coastal El Niño event: Looking to the past to prepare for the future.

Climate-related phenomena in Peru have been slowly but continuously changing in recent years beyond historical variability. These include sea surface temperature increases, irregular precipitation patterns and reduction of glacier-covered areas. In addition, climate scenarios show amplification in rainfall variability related to the warmer conditions associated with El Niño events. Extreme weather can affect human health, increase shocks and stresses to the health systems, and cause large economic losses. In this article, we study the characteristics of El Niño events in Peru, its health and economic impacts and we discuss government preparedness for this kind of event, identify gaps in response, and provide evidence to inform adequate planning for future events and mitigating impacts on highly vulnerable regions and populations. This is the first case study to review the impact of a Coastal El Niño event on Peru's economy, public health, and governance. The 2017 event was the third strongest El Niño event according to literature, in terms of precipitation and river flooding and caused important economic losses and health impacts. At a national level, these findings expose a need for careful consideration of the potential limitations of policies linked to disaster prevention and preparedness when dealing with El Niño events. El Niño-related policies should be based on local-level risk analysis and efficient preparedness measures in the face of emergencies.

Global trends in atmospheric layer thickness since 1940 and relationships with tropical and extratropical climate forcing

Global warming necessitates continual insights into changing atmospheric temperatures to enhance climate change monitoring and prediction. The thickness of an atmospheric layer serves as an effective proxy for the average temperature of that layer, playing a pivotal role in weather forecasting, understanding atmospheric dynamics, and detecting shifts in extreme weather conditions. This study investigates the global trends in thickness of the layer between 1000 hPa and 500 hPa, from 1940 to the present and evaluates the impact of tropical and extra-tropical climate modes on these trends. Our findings reveal a consistent, statistically significant positive trend in atmospheric layer thickness. However, the magnitude of this trend varies both regionally and seasonally. The most substantial absolute changes are observed in the high latitudes during their respective winter seasons; however, when considering global changes relative to each location’s unique historical variability, the most pronounced increase occurs in the tropics, specifically over central Africa, with a standard deviation increase of up to 0.03 σ yr−1. Based on the relative changes, the thickness over the Southern Hemisphere’s high-latitude landmasses is increasing at a faster pace during its winter compared to the Northern Hemisphere during its winter. Furthermore, our analysis of the impact of dominant tropical and extra-tropical climate modes revealed a strong correlation (R ∼ 0.9) between sea surface temperature changes in the Pacific warm pool region and the global average thickness. This relationship accounts for about 76% to 78% variance of the inter-annual variability in thickness. Consequently, we identify the increase in sea surface temperature in the Indo-Pacific warm pool as a significant controller of the rate and magnitude of atmospheric layer thickness changes globally. This underscores the crucial role of oceanic-atmospheric interactions in driving global climate variations and extremes.

Pengaruh Proper Rating, Industrial Type, dan Komite Audit terhadap Carbon Emission Disclosure:


 Climate change is the impact of global warming which has a negative impact on daily human activities. The negative impacts of climate change are increasing sea surface temperatures, changes in rainfall, extreme weather intensity and high waves. Pollution of carbon pollution is one of the problems that exist in environmental accounting. Through disclosure of carbon emissions, stakeholders can measure the company's role in reducing greenhouse gas (GHG) emissions and also indicate that the company cares about the environment. The purpose of this study is to determine the simultaneous and partial effects of PROPER Rating, Industrial Type, and Audit Committee influence on Carbon Emission Disclosure. The objects used as samples in this study are non-financial companies listed on the Indonesia Stock Exchange for the 2018-2021 period. The technique used in this study was purposive sampling with a total sample of 23 samples from 509 companies. The data analysis model used in this study is multiple linear regression analysis. This study gives the result that the PROPER Rating, Industrial Type, and Audit Committee variables simultaneously influence Disclosure of Carbon Emissions
 Keywords: Carbon Emission Disclosure, PROPER Rating, Industrial Type, and Committee Audit

Effect of Temperature on the Physiological Response of Enhalus acoroides Seedlings

Increasing sea surface temperatures as an effect of global warming can affect the survival of marine organism, among these marine organisms is seagrass. Temperature is one factor that can determine seagrass's physiological response in maintaining its life, including in the early stages of life in seagrass seedlings. This research aims to study the effect of temperature on the physiological response of Enhalus acoroides seedlings such as growth rate, leaf tissue anatomy, and chlorophyll content. The method used was an experiment in the laboratory. The seagrass seedlings were grown in an aquarium with three sea water temperature treatments (28°C, 31°C and 35°C) for 8 weeks of maintenance. The choice of sea water temperature treatment of 28°C (A) as a control is the optimal temperature range for seagrass, the treatment temperature of 31°C (B) refers to previous study, i.e. the temperature in the area of origin of the seagrass meadow, and the treatment temperature of 35°C (C) is considered as an estimate of temperature under the scenario of. The growth rate and the average leaf length were more optimal with a high chlorophyll content found at a temperature treatment of 28°C. The highest anatomical size of leaf tissue in the upper and lower epidermis was observed at 31°C, while the most extensive mesophyll tissue was observed at 35°C. In this study, temperature significantly affected the growth rate, average leaf length, anatomical structure of mesophyll tissue, and chlorophyll content of the Enhalus acoroides seedlings.

Recent Variations in the Size and Age Structure of the Population of Horse Mackerel <i>Trachurus mediterraneus</i> (Steindachner, 1868) on the South-Western Shelf of Crimea

The influence of the average annual sea surface temperature (SST) on the development of horse mackerel Trachurus mediterraneus on the south-western Crimean shelf has been shown. The changes in the main indicators of the population and their relationship with the change in the average annual SST (0.055°C/year) in 2000–2020 have been identified. Against the background of the observed increase in SST in recent years, the state of the horse mackerel population has improved: there has been an increase in the average age and, accordingly, the proportion of larger, well-fed individuals, and, in general, the average size and weight of fish. It has been shown that according to the nature of the change in the average annual SST, three periods can be distinguished: 2000−2007, 2008−2013 and 2014−2020.

The Role of Tropical Easterly Jet on the Bay of Bengal’s Tropical Cyclones: Observed Climatology and Future Projection

Abstract Tropical cyclones (TCs) in the Bay of Bengal (BoB) are among the most devastating events in nature, significantly influencing human life. They affect the region between April and December, being separated into two distinct phases: the premonsoon (April–June, AMJ) and postmonsoon (October–December, OND), with little activity during the monsoon peak. In this article, the influence of the tropical easterly jet (TEJ) on the observed BoB TC activity, and the expected changes under global warming conditions, are investigated using reanalyses and Coupled Model Intercomparison Project phase 6 (CMIP6) models. The general assumption is that TC activity should increase in response to warmer sea surface temperature (SST). However, several dynamical processes are needed to create organized convection, which is a prerequisite for TC development. The results show that the frequency and accumulated energy should decrease in the future (2020–49), compared to the historical climate (1950–79), during both phases. However, the northern BoB TCs’ intensity increases during OND. The change of the mean TEJ and intermittent shear relaxations in the future climate are found to play a major role in the change of TC activity rather than the SST. During AMJ, a southward shift of the mean TEJ and its intermittent shear relaxations are associated with reduced TC activity. During OND, the decrease of the frequency of TEJ and subtropical jet (STJ) intermittent shear relaxations are associated with the reduction of TC activity. This study clarifies the importance of both the mean and intermittency of the TEJ in determining the future of TC activity in the BoB.

Response of phytoplankton community structure to environmental changes in the coastal areas of northern China

In this study, we analyzed high-frequency data pertaining to phytoplankton and environmental factors in Jiaozhou Bay from December 10, 2004, to December 10, 2005 and from July 26, 2020, to August 1, 2021. Compared with 2004–2005, the abundance of phytoplankton during 2020–2021 presented a “two-peak pattern” of annual variation, and the number of species decreased significantly. The ecological types were dominated by eurythermal species, while cold-water species declined. The overall abundance showed a downward trend, and the peak period moved to a time with lower water temperature. This could be attributed to the increase in sea surface temperature. The increase in water temperature and intensification of eutrophication made the emergence of dominant species more inclined to be single; the diversity and stability of the community structure decreased. Generalized additive model (GAM) and network analysis showed that temperature was the main driving factor influencing the phytoplankton community structure, especially during the peak period. In addition, nitrogen and phosphorus were important factors influencing species composition and competitive advantage of phytoplankton.

Understanding the Role of Sea Surface Temperature and Urbanization on Severe Thunderstorms Dynamics: A Case Study in Surabaya, Indonesia

AbstractWithin the period 2014–2017, five hail events were reported in the city of Surabaya in Indonesia. Although deep convection commonly develops over the Maritime Continent, severe thunderstorms triggering hail events develop less frequently as specific atmospheric conditions are required. The rapid urbanization in Surabaya might have led to increased heat release to the atmosphere and to the deepening of convection, which raises the question of whether urbanization is the culprit of the recent hail events in Surabaya. Hence, for a selected hail event, we used the high‐resolution Weather Research and Forecasting model to understand the storm dynamics and to explore the role of urbanization, sea surface temperature, and aerosol concentration on the storm dynamics with a total of 11 scenarios. The control simulation reveals that low‐level convergence induced by a sea breeze creates instability. At the same time, the urban heat release enhances the energy supply to induce hail formation and retain the storm's lifetime over the city. A factor separation method revealed that the urbanization (added anthropogenic heat flux, urban aerosol, and the rise in building height) and the sea surface temperature increase contribute to the storm enhancement over Surabaya, producing two times higher updraft velocity, doubling the maximum graupel mass mixing ratio and finally resulting in 15%–30% higher accumulated precipitation over Surabaya, compared to the control simulation.

Analysis of marine heatwaves over the Bay of Bengal during 1982–2021

Anomalous increase in sea surface temperature and its impact on natural ecosystems greatly interests the research community. Here we investigate the causes, impacts, and trends of marine heat wave (MHW) events in the Bay of Bengal (BoB) from 1982 to 2021. A total of 107 MHW events have been isolated (> 90th percentile threshold) in this Indian Ocean region, and their variation in intensity, duration, and frequency has been investigated. Our research unveils that an average of three MHW events/year accompanied by a linearly increasing trend of 1.11 MHW events/decade has been observed over the study region. It was also found that the most intense event was observed in 2016, which continued for 69 days, and had a maximum intensity of 5.29 °C and a mean intensity of 2.03 °C (above climatology mean). Moreover, it was observed that the net heat flux, along with anticyclonic eddies, was the primary cause of MHW events. Anticyclonic eddies associated with positive sea surface height anomaly were observed (> 0.20 m) in the vicinity of the most intense MHW event. Additionally, climate change and climate modes like El Niño and Indian Ocean Dipole show a high positive influence on the MHW events. Furthermore, we have examined the MHW event recurrence patterns in various regions of the BoB. From the monthly analysis, it was found that August and November had the most occurrences of MHWs, while April and May had the most extreme MHW events.

Fishery-based adaption to climate change: the case of migratory species flathead grey mullet (Mugil cephalus L.) in Taiwan Strait, Northwestern Pacific.

The flathead gray mullet (Mugil cephalus L.) is a cosmopolitan fish that lives in warm and temperate zones over 42°N-42°S. It is a key fish species for industrial fishing off coastal Taiwan. Gray mullets enter the coastal waters of the southeastern Taiwan Strait (22°N-25°N) to spawn in winter and feed in the coastal and tidal waters of China (25°N-30°N). From 1986 to 2010, the annual catch of gray mullet decreased substantially and remained low. Although the Pacific Decadal Oscillation and El Niño-Southern Oscillation are recognized to affect gray mullet migration, the increase in sea surface temperature may be the main cause of the aforementioned decrease. We explored how weather changes affect fishing conditions and patterns at the gray mullet fishing grounds in Taiwan's coastal areas. Because of the decrease in gray mullet catches, the most common method for catching gray mullet in Taiwan's coastal areas between 1990 and 2010 was the use of drift or trawl nets instead of two-boat purse-seiner fleets. Since 2012, purse-seiner fleets have become the most common method for catching gray mullet. This trend indicates that the local fishing industry is adapting to changing environmental conditions.

Effects of paleogeographic changes and CO2 variability on northern mid-latitudinal temperature gradients in the Cretaceous

The Cretaceous ‘greenhouse’ period (~145 to ~66 million years ago, Ma) in Earth’s history is relatively well documented by multiple paleoproxy records, which indicate that the meridional sea surface temperature (SST) gradient increased (non-monotonically) from the Valanginian (~135 Ma) to the Maastrichtian (~68 Ma). Changes in atmospheric CO2 concentration, solar constant, and paleogeography are the primary drivers of variations in the spatiotemporal distribution of SST. However, the particular contribution of each of these drivers (and their underlying mechanisms) to changes in the SST distribution remains poorly understood. Here we use data from a suite of paleoclimate simulations to compare the relative effects of atmospheric CO2 variability and paleogeographic changes on mid-latitudinal SST gradient through the Cretaceous. Further, we use a fundamental model of wind-driven ocean gyres to quantify how changes in the Northern Hemisphere paleogeography weaken the circulation in subtropical ocean gyres, leading to an increase in extratropical SSTs.

Multiyear changes in oceanographic factors of the autumn migration of the Black Sea anchovy to the shores of Crimea from satellite data in 2000–2021

The purpose of this work is to analyze long-term changes in oceanographic indicators in the southeastern area of the northwestern Black Sea in November-December 2000–2021, which determine the migration activity and fishery performance of the Black Sea hammerhead off the coast of Crimea. Materials and methods used: The fishery statistics, data of information system Copernicus Marine Service of satellite altimetry and surface temperature of waters near the western coast of the Crimean Peninsula in November-December 2000–2021, graphic and statistical methods of the analysis of these data were used in work. Novelty: The element of novelty in the work is the use of oceanographic satellite data in the study of the behaviour of the Black Sea anchovy and long-term changes in its catch off the coast of Crimea. Result: During the period under consideration, the tendency of catch increase of the Black Sea anchovy of the Crimean coast is obvious. The main reasons for the activation of the autumn migration of the Black Sea anchovy to the shores of Crimea is a multi-year increase in sea surface temperature and the strengthening of south-eastern currents to the west of the Crimean Peninsula. Practical significance: The revealed causes of the mass autumn approaches of the Black Sea anchovy to the Crimean coast allow hoping for possibilities of their use in forecasting the results of the Black Sea anchovy fishing in the Crimean fishing area, and also give grounds for continuing research with special attention to monitoring of the Black Sea anchovy occurrence on the Crimean shelf.

Mortality in an off-shore predator critical habitat during the Northeast Pacific marine heatwave

Defining baseline mortality and trends in wildlife populations is imperative to understand natural and anthropogenic threats to overall population health and improve conservation measures for species, particularly in geographically confined habitats. The Guadalupe fur seal Arctocephalus townsendi (GFS) is a threatened pinniped that ranges throughout the west coast of Mexico with sporadic dispersion to higher latitudes. Their breeding habitat is restricted to Guadalupe Island, Mexico, which is vulnerable to periodic and cyclic warming of the Northeast Pacific Ocean. The impacts of environmental change on GFS health and reproductive success at Guadalupe Island are poorly defined and the aim of this study was to establish baseline pup (GFSn) mortality rates and primary causes of death during the 2013-2016 breeding seasons at Guadalupe Island. Interannual mortality rates and causes of death were compared by year, breeding seasons and by geographic location. The highest mortality rate in GFSn was in 2015 (14.7%), followed by 2014 (8.2%), 2016 (6.7%) and 2013 (5.6%). The presumptive causes of mortality of GFSn were consistent with other published long term otariids health surveys and included: emaciation (49%), trauma (24%), infectious disease (8%), drowning (4%) stillbirth/perinatal mortality (4%) and undetermined (11%). However, in 2015 and coinciding with northeast Pacific marine heatwave in 2014-2016, emaciation accounted for 54% of GFSn mortality in contrast to 9% in 2013. For GFSn, terrestrial habitat may influence mortality rates and causes of mortality but like other marine predators, marine habitat features, such as an increase in sea surface temperature are associated with changes in maternal care, nutritional status and pups survival. Monitoring mortality rate and causes in GFSn at Guadalupe Island is crucial to establish baseline health trends, document potential impacts on species demographics and recruitment during marine heatwaves and potential consequences in population recovery.

Ecosystem-level responses to multiple stressors using a time-dynamic food-web model: The case of a re-oligotrophicated coastal embayment (Saronikos Gulf, E Mediterranean)

Multiple stressors may combine in unexpected ways to alter the structure of ecological systems, however, our current ability to evaluate their ecological impact is limited due to the lack of information concerning historic trophic interactions and ecosystem dynamics. Saronikos Gulf is a heavily exploited embayment in the E Mediterranean that has undergone significant ecological alterations during the last 20 years including a shift from long-standing eutrophic to oligotrophic conditions in the mid-2000’s. Here we used a historical Ecopath food-web model of Saronikos Gulf (1998-2000) and fitted the time-dynamic module Ecosim to biomass and catch time series for the period 2001-2020. We then projected the model forward in time from 2021 to 2050 under 8 scenarios to simulate ecosystem responses to the individual and combined effect of sea surface temperature increase, primary productivity shifts and fishing effort release. Incorporating trophic interactions, climate warming, fishing and primary production improved model fit, depicting that both fishing and the environment have historically influenced ecosystem dynamics. Retrospective simulations of the model captured historical biomass and catch trends of commercially important stocks and reproduced successfully the marked recovery of marine resources 10 years after re-oligotrophication. In future scenarios increasing temperature had a detrimental impact on most functional groups, increasing and decreasing productivity had a positive and negative effect on all respectively, while fishing reductions principally benefited top predators. Combined stressors produced synergistic or antagonistic effects depending on the direction and magnitude of change of each stressor in isolation while their overall impact seemed to be strongly mediated via food-web interactions. Such holistic approaches advance of our mechanistic understanding of ecosystems enabling us to develop more effective management strategies in the face of a rapidly changing marine environment.

SEA SURFACE TEMPERATURE ANOMALIES FORMATION IN THE GULF OF MEXICO UNDER THE INFLUENCE OF HURRICANE SULLY ON SEPTEMBER11–17, 2020

Problem Statement and Purpose. Tropical cyclones are one of the most destructive natural phenomena on Earth, causing great social and economic losses. Given the destructive impact of tropical cyclones, the question of their study and the impact of climate change on their behavior is considerable scientific interest. Tropical cyclones "draw" energy from the surface of the ocean. Tropical cyclones arise and develop over the water surface, the temperature of which is not lower than 26 °C. In the case when a well-developed tropical cyclone hits the colder surface of the ocean, it begins to fill up quickly. Thus, a change in the SST on the path of the tropical cyclone may affect the further development and intensity of the storm, and as a result, its destructive power. The purpose of the work is to determine the deviations of the ocean surface temperature in the Gulf of Mexico under the influence of the passage of Hurricane Sally on September 11–17, 2020. Data & Methods. The analysis of sea surface temperature anomalies was performed on the basis of data from the NOAA OI SST V2 High Resolution Dataset Optimum Daily Interpolation of Sea Surface Temperature product, which is long-term climate data (period 1971–2000) and allows determination of daily of sea surface temperature anomalies with a step of 1/4°. Results. Against the background of positive Sea Surface Temperature anomalies associated with the tendency to increase Sea Surface Temperature in the Gulf of Mexico, which has been observed in recent decades, in the places where the trajectory of Hurricane Sally passed during the next day, the appearance of negative Sea Surface Temperature anomalies was noted, which had a focal character and were comparable in area to horizontal dimensions of the hurricane. Over time, cells of negative Sea Surface Temperature anomalies increased in area and temperature deviation. The highest Sea Surface Temperature anomalies values were observed on September 15–16, 2020 and were –1 °C. Negative anomalies persisted after the passage of Sally for a month, after which a positive Sea Surface Temperature anomalies formed on the surface of the Gulf of Mexico, occupying the entire water area of the Gulf. This duration of preservation of anomalies may be related to the circulation of the waters.

Hysteresis of the El Niño-Southern Oscillation to CO2 forcing.

El Niño-Southern Oscillation (ENSO) is the strongest interannual climate variability with far-reaching socioeconomic consequences. Many studies have investigated ENSO-projected changes under future greenhouse warming, but its responses to plausible mitigation behaviors remain unknown. We show that ENSO sea surface temperature (SST) variability and associated global teleconnection patterns exhibit strong hysteretic responses to carbon dioxide (CO2) reduction based on the 28-member ensemble simulations of the CESM1.2 model under an idealized CO2 ramp-up and ramp-down scenario. There is a substantial increase in the ensemble-averaged eastern Pacific SST anomaly variance during the ramp-down period compared to the ramp-up period. Such ENSO hysteresis is mainly attributed to the hysteretic response of the tropical Pacific Intertropical Convergence Zone meridional position to CO2 removal and is further supported by several selected single-member Coupled Model Intercomparison Project Phase 6 (CMIP6) model simulations. The presence of ENSO hysteresis leads to its amplified and prolonged impact in a warming climate, depending on the details of future mitigation pathways.

Economic loss as the impact of climate change on tuna fishermen in Northern Indonesian waters

This study aims to determine how big the impact of climate change is on the economic loss of the catch of Tuna fishermen in the northern waters of Aceh Province, Indonesia. Unfavorable climate change has an impact on decreasing fishing catches due to changes in seawater biophysics such as increasing sea surface temperatures, increasing wave height, and wind. The respondents in this study were 40 Tuna fishermen, located in 6 (six) villages in the waters of North Aceh., from two different WPPs, namely WPP 571 and 572. Data were collected by interview and using questionnaires. The results of this study indicate that there is a decrease in the level of welfare of coastal communities which is marked by a decrease in income levels caused by climate change. The results of the Present Value calculation also show that there is an economic loss for both small boats (<5GT) and large boats (>5GT), and the slope loss for small fishermen is steeper than for large fishermen. This indicates that large fishermen are more resilient to climate change than small fishermen. For an adaptation strategy, it is recommended that Tuna fishermen on the north coast of Aceh waters, both those in WPP 571 and 572, leave small boats and switch to larger boats (>5GT) which are proven to be more resistant to climate change than small boats (<5GT).

On the linkage between future Arctic sea ice retreat, Euro-Atlantic circulation regimes and temperature extremes over Europe

Abstract. The question to what extent Arctic sea ice loss is able to affect atmospheric dynamics and climate extremes over mid-latitudes still remains a highly debated topic. In this study we investigate model experiments from the Polar Amplification Model Intercomparison Project (PAMIP) and compare experiments with future sea ice loss prescribed over the entire Arctic, as well as only locally over the Barents and Kara seas, with a present-day reference experiment. The first step is to perform a regime analysis and analyze the change in occurrence frequencies of five computed Euro-Atlantic winter circulation regimes. Forced by future Arctic sea ice conditions, most models show more frequent occurrences of a Scandinavian blocking pattern in at least 1 winter month, whereas there is an overall disagreement between individual models on the sign of frequency changes of two regimes that, respectively, resemble the negative and positive phase of the North Atlantic Oscillation. Focusing on the ECHAM6 PAMIP experiments, we subsequently employ a framework of conditional extreme-event attribution. It demonstrates how detected regime frequency changes can be used to decompose sea-ice-induced frequency changes of European temperature extremes into two different contributions: one “changed-regime” term that is related to dynamical changes in regime occurrence frequencies and another more thermodynamically motivated “fixed-regime” contribution that is related to increased surface temperatures during a specific circulation regime. We show how the overall fixed-regime warming effect and also an increased Scandinavian blocking pattern frequency under future sea ice reductions can equally contribute to and shape the overall response signal of European cold extremes in midwinter. We also demonstrate how a decreased occurrence frequency of an anticyclonic regime over the eastern Atlantic dynamically counteracts the fixed-regime warming response and results in no significant changes in overall January warm-extreme occurrences. However, when compared to other characteristics of future climate change, such as the thermodynamical impact of globally increased sea surface temperatures, the effects of Arctic sea ice loss on European temperature extremes are of secondary relevance.

A statistical analysis of tropical salinity and its relationship to SST, highlighting two contrasting areas

Tropical air-sea interactions, near-surface salinity (Ss), and sea surface temperature (SST) fluctuations are studied via ocean reanalysis products in the period 1980–2020. The statistical work considers how the net heat and water balance affects mixed layer depth (MLD) and coupling between the upper ocean and atmosphere. Field correlations of Ss – SST exhibit significant negative values in tropical latitudes 10S-15 N, between the semi-permanent marine anticyclones and the equatorial trough. Highlighting contrasts in two areas: the tropical east Atlantic and subtropical southwest Indian Ocean, annual cycles, inter-annual fluctuations of 6 – 8 yr, and long-term downward trends of Ss emerge. The SW Indian Ocean exhibits large swings of net heat and water balance as the monsoon reverses, and steady running-correlations of Ss and SST. The E Atlantic has a subdued annual cycle, and running-correlations are weak and unsteady. In both areas the Ss lags SST by a month. A fresh minus salty composite analysis reveals that the two contrasting areas respond to opposing phases of the Southern Oscillation: E Atlantic (La Nina) and SW Indian (El Nino). Projected long-term trends for increased tropical marine rainfall could be neutralized by declining runoff from continental monsoons. Statistical outcomes infer that a 0.1 ppt reduction of near-surface salinity leads to a 5 m reduction of MLD and a 0.4 C increase of tropical SST, contributing to deeper atmospheric convection. Limitations of the study derive from inferences based on infrequent salinity measurements.