67 research outputs found

    Responses of Satellite Chlorophyll-a to the Extreme Sea Surface Temperatures over the Arabian and Omani Gulf

    Full text link
    peer reviewedExtreme events such as Marine Heat Waves (MHWs) and Low Chlorophyll-a (LChl-a) in the ocean have devastating impacts on the marine environment, particularly when they occur simultaneously (i.e., the compound of MHWs and LChl-a events). In this study, we investigate the spatiotemporal variability of MHWs and LChl-a events in the Arabian and Omani Gulf. For this purpose, we used satellite-based high-resolution observations of SST (0.05° × 0.05°; from 1982 to 2020) and chlorophyll-a concentration data (0.04° × 0.04°; from 1998 to 2020). Hourly air temperature, wind, and heat flux components from the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis (ERA5) were used to explain the link between these extreme events and atmospheric forcings. Moreover, our results revealed that the annual frequency of MHW and LChl-a is related to the El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD). The results revealed an average SST warming trend of about 0.44 ± 0.06 °C/decade and 0.32 ± 0.04 °C/decade for the Arabian Gulf (AG) and the Gulf of Oman (OG), respectively. This warming rate was accompanied by MHW frequency and duration trends of 0.97 events/decade and 2.3 days/decade, respectively, for the entire study region from 1982 to 2020. The highest annual MHW frequencies were recorded in 2010 (6 events) and 2020 (5 events) associated with LChl-a frequency values of 4 and 2, respectively. La Niña events in 1999, 2010, 2011, and 2020 were associated with higher frequencies of MHW and LChl-a. The positive phase of IOD coincides with high MHW frequency in 2018 and 2019. The longest compound MHW and LChl-a event with a duration of 42 days was recorded in 2020 at OG. This extreme compound event was associated with wind stress reduction. Our results provide initial insights into the spatiotemporal variability of the compound MHW and LChl-a events that occurred in the AG and OG

    Extreme marine heatwaves and cold-spells events in the Southern North Sea: classifications, patterns, and trends

    Get PDF
    In this study, we examined the long-term spatiotemporal trend of marine heatwaves (MHW) and marine cold spells (MCS) characteristics in the southern North Sea over the last four decades (1982-2021). We then estimated the difference between their annual mean values and the possible relationship with the large-scale climate modes of natural sea surface temperature (SST) and atmospheric variability using satellite SST data. The SST warming rate was 0.33 ± 0.06°C/decade and was associated with an increase in MHW frequency (0.85 ± 0.39 events/decade) and a decrease in MCS frequency (-0.92 ± 0.40 events/decade) over the entire period. We found a distinct difference between the annual mean values of MHW and MCS characteristics, with a rapid increase in total MHW days (14.36 ± 8.16 days/decade), whereas MCS showed an opposite trend (-16.54 ± 9.06 days/decade). The highest MHW frequency was observed in the last two decades, especially in 2014 (8 events), 2020 (5 events), and 2007 (4 events), which were also the warmest years during the study period. Only two years (2010 and 2013) in the last two decades had higher MCS frequency, which was attributed to the strong negative phase of the North Atlantic Oscillation (NAO). Our results also show that on the annual scale, both the East Atlantic Pattern (EAP) and the Atlantic Multidecadal Oscillation (AMO) play a more important role in the formation of the MHW in the southern North Sea than the other teleconnections (e.g., the NAO). However, the NAO made the largest contribution only in the winter. Strong significant (p < 0.05) positive/negative correlations were found between oceanic and atmospheric temperatures and the frequency of MHW/MCS. This suggests that with global warming, we can expect an increase/decrease in MHW/MCS occurrences in the future

    Sea Surface Temperature: From Observation to Applications

    Get PDF
    This book covers a broad range of sea surface temperature studies from very different points of view and scales; the SST is observed from very local to regional and oceanic scales. The chapters of this book move from local and remote data sensing validation to local and regional trend analysis, and also give some insight into marine heatwaves and future climate scenarios

    Impacto das Ondas de Calor Marinhas na Concentração de Clorofila-A no Atlântico Sul Sudoeste

    Get PDF
    TCC(graduação) - Universidade Federal de Santa Catarina. Centro de Filosofia e Ciências Humanas. OceanografiaOndas de calor marinhas (OCMs) são eventos caracterizados pelo aumento anômalo da temperatura nos oceanos, que podem ter enormes impactos sobre ecossistemas marinhos. O presente estudo investigou a frequência, intensidade e duração de OCMs no Atlântico Sul sudoeste para o período de 1982-2019 e seu impacto na concentração de Clorofila-a (biomassa fitoplanctônica) para o período de 2002-2017. Para tal foram utilizados os dados diários de temperatura da superfície do mar (TSM) para a detecção e análise das OCMs, e dados diários de concentração de clorofila-a da superfície do mar (CSM). As OCMs foram identificadas e as concentrações de CSM foram analisadas em relação a sua distribuição espacial nos dias de ocorrência das OCMs. Os resultados mostraram que as OCMs identificadas ocorreram em toda a região atingindo intensidades máximas de 4,5°C. A análise de tendências para o período de 1982- 2019 mostrou que houve não só um aumento na frequência, mas também na intensidade e duração dos eventos de OCM para a região de 25-50°S e 20-60°O para todas as estações, principalmente no verão e no inverno austral. Quando os eventos de OCMs são mais frequentes e intensos, há uma redução nas concentrações de CSM nas áreas de oceano aberto, longe da região costeira da pluma do Rio da Prata. Quando as OCMs são menos frequentes e fracas, a CSM tende a aumentar, mas esse impacto não é tão claro. Na região costeira de Cabo Frio, no verão, houve uma redução na concentração de CSM associado a ocorrência de OCMs. Assim, o estudo mostrou que as OCMs ocorreram no Atlântico Sul sudoeste e possivelmente impactam indiretamente ecossistemas marinhos através da redução na concentração da CSM.Marine heat waves (MHWs) are events characterized by anomalous increases in ocean temperatures, which can have enormous impacts on marine ecosystems. The present study investigated the frequency, intensity and duration of MHWs in the Southwest Atlantic for the period 1982-2019 and their impact on chlorophyll-a concentration (phytoplankton biomass) for the period 2002-2017. This was done using daily sea surface temperature (SST) data for the detection and analysis of MHWs and daily sea surface chlorophyll-a concentration (SSC) data. The MHWs were identified and the SSC concentrations were analyzed in relation to their spatial distribution on the days of MHWs occurrence. The results showed that the identified MHWs occurred throughout the region reaching maximum intensities of 4.5°C. The analysis of tendencies for the period 1982- 2019 showed that there was not only an increase in the frequency but also in the intensity and duration of MHW events for the region of 25-50°S and 20-60°W for all seasons, mainly in the summer and austral winter. When MHW events are more frequent and intense, there is a reduction in SSC concentrations in the open ocean areas, far from the coastal region of the Rio de la Plata plume. When MHWs are less frequent and weaker, SSC tends to increase, but this impact is not so clear. In the coastal region of Cabo Frio, in the summer, there was a reduction in the concentration of SSC associated with the occurrence of MHWs Thus, the study showed that MHWs occurred in the southwest Atlantic and possibly indirectly impact marine ecosystems by reducing the concentration of SSC

    Exploring, exploiting and evolving diversity of aquatic ecosystem models: A community perspective

    Get PDF
    Here, we present a community perspective on how to explore, exploit and evolve the diversity in aquatic ecosystem models. These models play an important role in understanding the functioning of aquatic ecosystems, filling in observation gaps and developing effective strategies for water quality management. In this spirit, numerous models have been developed since the 1970s. We set off to explore model diversity by making an inventory among 42 aquatic ecosystem modellers, by categorizing the resulting set of models and by analysing them for diversity. We then focus on how to exploit model diversity by comparing and combining different aspects of existing models. Finally, we discuss how model diversity came about in the past and could evolve in the future. Throughout our study, we use analogies from biodiversity research to analyse and interpret model diversity. We recommend to make models publicly available through open-source policies, to standardize documentation and technical implementation of models, and to compare models through ensemble modelling and interdisciplinary approaches. We end with our perspective on how the field of aquatic ecosystem modelling might develop in the next 5–10 years. To strive for clarity and to improve readability for non-modellers, we include a glossary

    Implementation of Sensors and Artificial Intelligence for Environmental Hazards Assessment in Urban, Agriculture and Forestry Systems

    Get PDF
    The implementation of artificial intelligence (AI), together with robotics, sensors, sensor networks, Internet of Things (IoT), and machine/deep learning modeling, has reached the forefront of research activities, moving towards the goal of increasing the efficiency in a multitude of applications and purposes related to environmental sciences. The development and deployment of AI tools requires specific considerations, approaches, and methodologies for their effective and accurate applications. This Special Issue focused on the applications of AI to environmental systems related to hazard assessment in urban, agriculture, and forestry areas
    corecore