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In this study, we evaluated extreme climate indicators for precipitation and temperature in the Brazilian Legal Amazon (BLA) from 1961 to 2021. Data from 38 National Institute of Meteorology (INMET) weather stations with a record failure rate less than 12% were used, and RClimDex software and the Mann–Kendall test, Pettitt test, standard normal homogeneity test (SNHT), and Buishand test were employed to analyse the data. The results showed increased extreme rainfall events, including the annual total rainfall divided by wet days (SDII). More frequent discontinuities were observed in the 1980s (SNHT) and 1990s (Pettitt and Buishand tests). The extreme temperature climate indicators also significantly increased, particularly in the 1990s. These increases are likely linked to changes in local climate conditions due to agricultural expansion, intensified industrial activities, and regional urbanization. This study underscores the need for proactive measures to curb illegal deforestation and reduce CO2 emissions and further research to better understand and mitigate the adverse impacts of these changes on the BLA environment and local communities. [ABSTRACT FROM AUTHOR]

The contribution of surface and lateral forcing to the observed Arabian Gulf warming trend is studied based on the results of a high-resolution (1/100°, 60 vertical layers) MIT general circulation model (MITgcm) covering the period 1993-2021. The model validation against available observations reveals that the simulation satisfactorily reproduces the main features of the Arabian Gulf's dynamics and their variability. We show that the heat content of the Arabian Gulf generally follows the reported variability of sea surface temperature, with significant increasing trends of 0.1 x 107 J m-3 and 0.2°C per decade. The interannual variability of the heat content is dominated by the surface heat fluxes, while the long-term warming of the basin is primarily driven by lateral fluxes. The analyses of the heat exchanges through the Strait of Hormuz indicate a pronounced upward trend in the transported heat toward the Arabian Gulf, which is associated with an increase in both the volume and temperature of the exchanged waters. Considering the inflow and outflow in the Strait separately, the temperature increase is more prominent in the inflowing waters; however, the dominant factor driving the rising trend in heat content exchanges is the increase in the volume of waters being exchanged. This implies that the observed warming of the Arabian Gulf during the investigated period is directly related to the acceleration of its overturning circulation. [ABSTRACT FROM AUTHOR]

Based on National Oceanic and Atmospheric Administration (NOAA, USA) and Japan Meteorological Agency (JMA) climate data sets for 1982–2021, regional features and trends of interannual variations in water temperature in the upper 2200-m layer of the tropical Pacific Ocean were investigated, as well as their possible relationships with climatic characteristic variations. The obtained results describe the three-dimensional structure of temperature anomalies and heat content variability in the water column and warming rate in different areas for specific phases of the recent global warming. [ABSTRACT FROM AUTHOR]

The contribution of surface and lateral forcing to the observed Arabian Gulf warming trend is studied based on the results of a high-resolution (1/100°, 60 vertical layers) MIT general circulation model (MITgcm) covering the period 1993–2021. The model validation against available observations reveals that the simulation satisfactorily reproduces the main features of the Arabian Gulf’s dynamics and their variability. We show that the heat content of the Arabian Gulf generally follows the reported variability of sea surface temperature, with significant increasing trends of 0.1 × 107 J m−3 and 0.2°C per decade. The interannual variability of the heat content is dominated by the surface heat fluxes, while the long-term warming of the basin is primarily driven by lateral fluxes. The analyses of the heat exchanges through the Strait of Hormuz indicate a pronounced upward trend in the transported heat toward the Arabian Gulf, which is associated with an increase in both the volume and temperature of the exchanged waters. Considering the inflow and outflow in the Strait separately, the temperature increase is more prominent in the inflowing waters; however, the dominant factor driving the rising trend in heat content exchanges is the increase in the volume of waters being exchanged. This implies that the observed warming of the Arabian Gulf during the investigated period is directly related to the acceleration of its overturning circulation.

Based on the NOAA climate datasets and Global Ocean Data Assimilation System (GODAS), trends and regional features of interannual changes in water temperature on the surface and in the upper 1000-meter layer of the Japan Sea were analyzed. Their possible causal relationships with variations in atmospheric pressure, climatic indices, and thermal characteristics in the adjacent area of the Kuroshio energetically active zone were determined. The results of the study made it possible to describe a three-dimensional structure of the anomalies of temperature and heat content in various layers of the sea water column and to quantify a rate of warming in different parts of the study area under conditions of the current phase of global warming. [ABSTRACT FROM AUTHOR]

The European climate is changing displaying profound impacts on agriculture, thus strongly reaching the scientific community's attention. In this review, the compilation of selected scientific research on the agroclimatic conditions' changes and their impact on the productivity parameters (phenology timing, product quality and quantity) of grapevines and on the spatiotemporal characteristics of the viticultural areas are attempted for the first time. For this purpose, a thorough investigation through multiple search queries was conducted for the period (2005–2021). Overall, increasing (decreasing) trends in critical temperature (precipitation) parameters are the reality of the recent past with visible impacts on viticulture. The observed climate warming already enforces emerging phenomena related to the modification of the developmental rate (earlier phenological events, shortening of phenological intervals, lengthening of the growing season, earlier harvest), the alteration of product quality, the heterogeneous effects on grapevine yield and the emergence of new cool-climate viticulture areas highlighting the cultivation's rebirth in the northern and central parts of the continent. The vulnerability of the wine-growing ecosystem urges the integration of innovative and sustainable solutions for confronting the impacts of climate change and safeguarding the production (quantity and quality) capacity of viticultural systems in Europe under a continuously changing environment. [ABSTRACT FROM AUTHOR]

The influence of global warming on mid-depth water mass ventilation in the Japan Sea was investigated using both Argo-based and ship-based hydrographic datasets. The Argo-based dataset of the entire Japan Sea area revealed a warming trend during the past two decades in the upper portion of the Japan Sea Proper Water (UJSPW), which lies at intermediate depths from just under the main thermocline to approximately 1000 m. The warming rates in the southern Japan Sea are generally greater than those in the northern sea by a factor of 2–3. Long-term hydrographic data obtained over the last five decades in the northeast and southeast of the sea revealed that higher warming rates in the southern sea began from 2008, although a significant warming in both northern and southern seas was initiated from the late 1980s. A stagnation in the UJSPW formation from the late 1980s was suggested by a positive shift in the winter sea surface temperature in its formation region and a decreasing trend in dissolved oxygen concentration during the 1990s. In addition, a vertical multi-box model demonstrated that an imbalance between the heating from the upper layer and the cold water supply from its source region induces a warming in the UJSPW. We conclude that a significant change in the mid-depth water mass ventilation occurred in the entire Japan Sea in the late 1980s due to a stagnation in the UJSPW formation. Subsequently, a modest event in the mid-depth water mass ventilation have occurred since 2008. The higher warming rates in the southern sea than those in the northern sea in the event suggest a reduction in cold UJSPW supply to the southern sea from its formation region.

Surface air temperature trends and extreme events are of global concern and they are related. Here, we show that the occurrence of record hot years over different latitudes from 1960 to 2019 are more strongly correlated with the observational annual mean temperature trends normalized by internal variability. Compared with the raw trends showing Arctic amplification, the normalized trends show a tropical amplification over land. Two hot spots with more frequent occurrence of record hot years are identified: northern hemisphere ocean (vs. land) and southern hemisphere tropical land (vs. mid‐ and high‐latitude lands). Ensemble mean results from 32 Earth system models agree with observations better than individual models, but they do not reproduce observed large differences in correlations across latitudes between normalized trends and record‐breaking events over land versus ocean. Our results enable the quantification of record hot year occurrence through normalized warming trends and provide new metrics for model evaluation and improvement. Plain Language Summary: Surface air temperature trends and extreme hot events are of global concern and they are related. Based on generic time series, it was argued that the occurrence of extreme events depends on the normalized, rather than the raw, trends. However, it remains unknown whether this dependence is relevant to the comparison of extreme hot event occurrences over different regions, such as the Arctic versus Amazon. Here, we show that the occurrence of record hot years over different regions from 1960 to 2019 are more strongly correlated with the observational annual mean temperature trends normalized by internal variability. Compared with the raw trends showing Arctic amplification, the normalized trends show a tropical amplification over land. Two hot spots with more frequent occurrence of record hot years are identified: Northern hemisphere ocean (vs. land) and southern hemisphere tropical land (vs. mid‐ and high‐latitude lands). Results averaged from 32 Earth system models agree with observations better than individual models, but they do not reproduce observed large differences in correlations across latitudes between normalized trends and record‐breaking events over land versus ocean. Our results enable the quantification of record hot year occurrence through normalized warming trends and provide new metrics for model evaluation and improvement. Key Points: Occurrence of record hot years in different latitudes is better correlated with normalized, rather than raw, temperature trendsCompared with the raw trends showing Arctic amplification, the normalized trends show a tropical amplification over landEarth system models' correlations between normalized trends and record‐breaking events are as high over land as over ocean, unlike in observations [ABSTRACT FROM AUTHOR]

The European climate is changing displaying profound impacts on agriculture, thus strongly reaching the scientific community’s attention. In this review, the compilation of selected scientific research on the agroclimatic conditions’ changes and their impact on the productivity parameters (phenology timing, product quality and quantity) of grapevines and on the spatiotemporal characteristics of the viticultural areas are attempted for the first time. For this purpose, a thorough investigation through multiple search queries was conducted for the period (2005–2021). Overall, increasing (decreasing) trends in critical temperature (precipitation) parameters are the reality of the recent past with visible impacts on viticulture. The observed climate warming already enforces emerging phenomena related to the modification of the developmental rate (earlier phenological events, shortening of phenological intervals, lengthening of the growing season, earlier harvest), the alteration of product quality, the heterogeneous effects on grapevine yield and the emergence of new cool-climate viticulture areas highlighting the cultivation’s rebirth in the northern and central parts of the continent. The vulnerability of the wine-growing ecosystem urges the integration of innovative and sustainable solutions for confronting the impacts of climate change and safeguarding the production (quantity and quality) capacity of viticultural systems in Europe under a continuously changing environment.

This study examines the problematic impact of selecting a different base period (colder 1961–1990 vs. warmer 1988–2017), on the trend magnitude of widely used percentile‐based extreme temperature indices (e.g., warm/cold spells, warm/cold days and nights). The percentile‐based indices are part of a core set of indices (27 in total) that have become a common standard for monitoring climate change, as recommended by the Expert Team on Climate Change Detection and Indices (ETCCDI). The indices were designed to be comparable across regions provided that similar analyses are employed. Unfortunately, the use of different base periods and periods of interest to explore local and global climate change undermines the comparability of findings across regions. When utilizing "day‐count" indices with fixed thresholds, the use of different base/reference periods changes the intercept without influencing the slope (for a given period length). However, this assertion does not hold with percentile‐based indices. Our analyses show that percentile‐based temperature indices (e.g., days with temperature below the 10th or above the 90th percentiles) are particularly susceptible to the problematic use of different base periods. Hence, using percentile‐based indices may have adverse effects on researchers' conclusions. The current paper reports the results of a comparative study that used different base periods for the most commonly used percentile‐based extreme temperature indices. It was found that the (negative) trend magnitude of the cold percentile‐based indices (frequency of cold days and nights and cold spells) is strongly amplified while the (positive) trend magnitude of the warm indices (frequency of warm days and nights and warm spells) is dramatically diminished when percentiles were derived from a base period that included records from the last two decades (e.g., 1981–2010, 1988–2017). These features are even more pronounced when the study period covers only the last 30–40 years. [ABSTRACT FROM AUTHOR]

A number of studies have noted that the use of distinct reference periods when comparing indices measuring the frequency of days exceeding a particular temperature percentile threshold leads to apparently different behaviour. We show that these differences arise because of the interplay between the increasing temperatures and the choice of reference period. The time series of the indicators calculated using the different reference periods are offset, as expected, but also diverge. Linear trends calculated over the same period from the same underlying data but where different reference periods have been used are substantially different if a change in climatological conditions has occurred between the two reference periods. We show this not only occurs in our simple empirical approach, but also for the averages of gridded observational and reanalysis datasets and also at a station level. This has implications for data set comparisons using trends in temperature percentile indices that are based on different reference periods. It also has implications for updates to standard reference periods used to monitor the climate.

Global surface evapotranspiration is one of the most significant components of the response of the water cycle to a warming climate. However, trends in surface evapotranspiration differ considerably from the trend in climate warming according to recent studies, with some studies even showing an opposing trend. The reason for this difference in the response of surface evapotranspiration to climate warming is still not completely understood. We validated the gridded FLUXNET evapotranspiration dataset and the Global Land Surface Assimilation Dataset (GLDAS) against evapotranspiration data observed in northern China using the eddy covariance system. The response of surface evapotranspiration to an increase in temperature varied with the type of climate (classified by the amount of precipitation) and the trend of surface evapotranspiration with warming showed similar features to the transitions between these climate types. The climate type with precipitation in the range of 250–350 mm was the most sensitive to the effects of warming on evapotranspiration. In more humid climates, surface evapotranspiration increased with increasing temperature, whereas in drier climates surface evapotranspiration decreased with increasing temperature. A similar response of evapotranspiration to increasing temperatures was also observed elsewhere in regions of climate transition. There are two main mechanisms of evapotranspiration: (1) an increase in temperature resulting in a direct increase in potential evapotranspiration; and (2) an increase in temperature resulting in a loss of soil moisture due to the increase in evapotranspiration, which in turn will indirectly suppress surface evapotranspiration due to the loss of vegetation. [ABSTRACT FROM AUTHOR]

We use 25 years of Advanced Very High-Resolution Radiometer (AVHRR) data from NOAA Polar Orbiting Environmental Satellites received by six Australian and two Antarctic reception stations to construct a detailed climatology of sea surface temperature (SST) around Australasia. The data have been processed following international GHRSST protocols to help reduce instrument bias using in situ data, with only night-time nearly cloud-free data used to reduce diurnal bias and cloud contamination. A pixel-wise climatology (with four annual sinusoids) and linear trend are fit to the data using a robust technique and monthly non-seasonal percentiles derived. The resulting Atlas, known as the SST Atlas of Australian Regional Seas (SSTAARS), has a spatial resolution of ~2 km and thus reveals unprecedented detail of regional oceanographic phenomena, including tidally-driven entrainment cooling over shelves and reef flats, wind-driven upwelling, shelf winter water fronts, cold river plumes, the footprint of the seasonal boundary current flows and standing mesoscale features in the major offshore currents. The Atlas (and associated statistics) will provide a benchmark for high-resolution ocean modelers and be a resource for ecosystem studies where temperatures, and their extremes, impact on ocean chemistry, species ranges and distribution. [ABSTRACT FROM AUTHOR]

This paper deals with the analysis of the MET Office Hadley Centre's sea surface temperature data set (HadSST3) by using long-range dependence techniques. We incorporate linear and segmented trends using fractional integration, and thus permitting long memory behavior in the detrended series. The results indicate the existence of warming trends in the three series examined (Northern and Southern Hemispheres along with global temperatures), with orders of integration which are in the range (0.5, 1) and thus implying nonstationary long memory and mean reverting behavior. This is innovative compared with other works that assume short memory behavior in the detrended series. Allowing for segmented trends two features are observed: increasing values in the degree of dependence of the series across time and significant warming trends from 1940 onwards. [ABSTRACT FROM AUTHOR]

In order to assess the performance of two versions of the IAP/LASG Flexible Global Ocean-Atmosphere-Land System (FGOALS) model, simulated changes in surface air temperature (SAT), from natural and anthropogenic forcings, were compared to observations for the period 1850-2005 at global, hemispheric, continental and regional scales. The global and hemispheric averages of SAT and their land and ocean components during 1850-2005 were well reproduced by FGOALS-g2, as evidenced by significant correlation coefficients and small RMSEs. The significant positive correlations were firstly determined by the warming trends, and secondly by interdecadal fluctuations. The abilities of the models to reproduce interdecadal SAT variations were demonstrated by both wavelet analysis and significant positive correlations for detrended data. The observed land-sea thermal contrast change was poorly simulated. The major weakness of FGOALS-s2 was an exaggerated warming response to anthropogenic forcing, with the simulation showing results that were far removed from observations prior to the 1950s. The observations featured warming trends (1906-2005) of 0.71, 0.68 and 0.79°C (100 yr) for global, Northern and Southern Hemispheric averages, which were overestimated by FGOALS-s2 [1.42, 1.52 and 1.13°C (100 yr)] but underestimated by FGOALS-g2 [0.69, 0.68 and 0.73°C (100 yr)]. The polar amplification of the warming trend was exaggerated in FGOALSs2 but weakly reproduced in FGOALS-g2. The stronger response of FGOALS-s2 to anthropogenic forcing was caused by strong sea-ice albedo feedback and water vapor feedback. Examination of model results in 15 selected subcontinental-scale regions showed reasonable performance for FGOALS-g2 over most regions. However, the observed warming trends were overestimated by FGOALS-s2 in most regions. Over East Asia, the meridional gradient of the warming trend simulated by FGOALS-s2 (FGOALS-g2) was stronger (weaker) than observed. [ABSTRACT FROM AUTHOR]

Mixed layer depth (MLD) variability from seasonal to decadal time scales in the Bay of Biscay is studied in this work. A hydrographic time series running since 1991 in the study area, a climatology of the upper layer vertical structure based on the topology of this temperature profile time series and a one-dimensional water column model have been used for this purpose. The prevailing factors driving MLD variability have been determined with detail, and agreement with observations is achieved. Tests carried out to investigate climatological profile skill to reproduce the upper layer temporal evolution have demonstrated its ability to simulate variability at seasonal time scales and reproduce the most conspicuous events observed. This has enabled us to carry out a reconstruction of the MLD variability for the last 60 years in the study area. Favourable sequence of intense mixing events explains interannual differences and cases of extraordinary deepening of winter mixed layer. The negative phase of the Eastern Atlantic pattern seems to determine important interannual variability through intense episodes of cooling and mixing as in winter 2005 in the Bay of Biscay. Low-frequency variability is also observed. A very striking and unexpected shallower winter MLD during the 1970s and 1980s than those observed from 1995 has been found. Simulation results support this counter-intuitive outcome of shallower winter mixed layers concurrent with generalized upper water warming trends reported on several occasions for the area. The long-term trends in MLD seem related with decadal variability in the North Atlantic Oscillation, being in phase and opposition with other deepening-shallowing cycles found from subtropical-to-subpolar areas in the North Atlantic. [ABSTRACT FROM AUTHOR]

Abstract: Climate change in the Mediterranean region cannot be understood without taking into account changes in the Mediterranean Sea, which is an important source of moisture and heat for the Mediterranean climate system. Many research papers have been published in the last two decades increasing our knowledge about long-term trends and inter-annual variability of temperature and salinity in the Western Mediterranean. Although recent changes have been better documented, there remain uncertainties because different results are obtained depending on the period of time analyzed or the geographic region selected. This paper analyses the regional, seasonal and decadal variability of sea surface temperature in the Western Mediterranean basins (Northern (Ligurian Sea and Gulf of Lions), Balearic, Algerian and Alboran) by means of thermal satellite images. Monthly data from the PO.DAAC (Physical Oceanography Distributed Active Archive Center) have been processed for the period 1985–2007. Results show an averaged warming linear trend of 0.03°C/yr. This rate is higher during the spring (0.06°C/yr) in all the basins and the highest values were registered in the Northern basin in June. The study suggests that an early warming of the Sea is occurring in all the basins during the spring, with an increment of 0.5–1°C in the mean SST of April, May and June over the two decades studied. The analysis of thermal anomalies confirms the warming trend with a dominance of negative anomalies during 1985–1996 and a dominance of positive anomalies during the last decade (1997–2007). Intense anomalies are more frequent in the Northern basin. [Copyright &y& Elsevier]

Abstract: We analyse hydrographic, meteorological and sea level time series in the continental shelves of Málaga Bay and L''Estartit, in the South and North Western Mediterranean. We have detected an important reduction of the warming rates reported for the 90s decade, showing that the warming process of the Mediterranean is superimposed on several years lasting oscillations. These accelerations or interruptions, typically account for a fraction of the total trend, and therefore they are not able to obscure the warming detection if the time series are long enough. On the other hand, they can produce artificial results if the time series are short when compared with the length of these cycles. The warming of the shelf waters, its acceleration during the 90s and the reversal during the beginning of the XXI century, are also observed in air temperature time series along the Spanish Mediterranean. We have also checked the influence of the warming acceleration/disruption on the sea level rise. Mean sea level trends are around 1 mm/yr when long time series are analysed, but shorter time series can result in rising trends as large as 13 mm/yr, for accelerated warming periods, or even no sea level change for reversals of the warming trends. Another factor to study is the influence of the NAO on these warming/cooling periods as well as on the strength of upwelling favourable winds, which could have a great importance on shelf ecosystems. [Copyright &y& Elsevier]

• Late pruning is a valuable technique to reduce grapes sugar content at harvest. • Grapes organic acids degradation is postponed in late-pruned vines. • Late pruning induces a variability in the intra-spur growth pattern. • The delaying effect is independent from the vine leaf area-to-fruit ratio. Late pruning is an emerging cultural technique aimed at deferring ripening kinetics and reducing the negative effects of warming trends on grape maturity. It relies on the inhibition of basal nodes and on the postponement of the progression of phenological stages. As a consequence, late pruning is capable of maintaining at harvest a moderate sugar concentration and an adequate acidity level in grapes. This work was intended to deepen the effects of late pruning, focusing on the intra-vine phenology variability and progression as well as on the interactions existing between the changes in vine balance and the ripening time shift. Two experiments were conducted over two consecutive years in different vineyards located in Abruzzo (central Italy), comparing late pruning (LP) applied when unpruned canes had shoots with two/three leaves already unfolded (phenological stage BBCH 12/13) with standard winter pruning executed at dormancy (WP). LP shifted phenology and led to a significant variability in the development stages detected on shoots arising from the different nodes of the spurs, whereas in WP vines shoots arising from count-nodes developed in synchrony. LP successfully delayed ripening, but the outputs of the two experiments were different: LP postponed sugars accumulation and the decrease of acidity in both experiments (-2° Brix and +2.5 g/L at harvest, as an average of the two experiments) though the yield was negatively affected only in the first experiment (-47% as compared to WP). Late spur-pruning confirmed its efficacy in spreading grapes maturity and maintaining higher acidity along with a reduced sugar concentration. The delaying effect seems to be quite independent from the seasonal vine balance given as leaf area-to-fruit ratio. The study provided further clarification of the physiological bases underlying vine response to delayed winter pruning and indicated robustness of its effects regardless environmental conditions and degree of vine balance. [ABSTRACT FROM AUTHOR]