Is the Atlantic a Source for Decadal Predictability of Sea-Level Rise in Venice?

Sea-level rise is one of the most critical consequences of global warming, with potentially vast impacts on coastal environments and societies. Sea-level changes are spatially and temporally heterogeneous on multiannual-to-multidecadal timescales. Here, we demonstrate that the observed rate of winter sea-level rise in the Italian city of Venice contains significant multidecadal fluctuations, including interdecadal periods of near-zero trend. Previous literature established a connection between the local sea-level trend in Venice and over the broad subpolar and eastern North Atlantic. We demonstrate that for multidecadal variations in sea-level trend such connection holds only since the mid-20th Century. Such multidecadal sea-level fluctuations relate to North Atlantic sea-surface temperature changes described by the Atlantic multidecadal variability, or AMV. The link is explained by combined effect of AMV-linked steric variations in the North Atlantic propagating in the Mediterranean Sea, and large-scale atmospheric circulation anomalies over the North Atlantic with a local effect on sea level in Venice. We discuss the implications of such variability for near-term predictability of winter sea-level changes in Venice. Combining available sea-level projections for Venice with a scenario of imminent AMV cooling yields a slowdown in the rate of sea-level rise in Venice, with the possibility of mean values remaining even roughly constant in the next two decades as AMV effects contrast the expected long-term sea-level rise. Acknowledging, understanding, and communicating this multidecadal variability in local sea-level rise is crucial for management and protection of this world-class historical site.Plain Language Summary Environmental and socioeconomic impacts of sea-level rise are one of the major concerns of global warming. Here, we consider the case of the Italian city of Venice, one of the iconic locations for the potentially dramatic effects of sea-level rise. We show that the sea-level evolution in Venice during the past similar to 150 years contains strong multidecadal fluctuations, so that periods of more than two decades when there is little or no trend occurred even in the recent past. We link these fluctuations with sea-level and climatic variations in the North Atlantic. In particular, we focus on the phenomenon known as Atlantic multidecadal variability, or AMV, which describes the alternation over multidecadal periods of warm and cold phases of the North Atlantic surface. Our results indicate that warm AMV phases are linked to faster sea-level rise in Venice and vice versa. Accordingly, we build sea-level rise scenarios for Venice until 2035 by considering an imminent AMV cooling as suggested by recent studies. The scenarios yield a temporary slowdown of sea-level rise as the AMV contrasts the effects of global warming. This sea-level variability can strongly impact on the management of protective measures against flooding currently operative in Venice

Robust decadal hydroclimate predictions for northern Italy based on a twofold statistical approach

The Mediterranean area belongs to the regions most exposed to hydroclimatic changes, with a likely increase in frequency and duration of droughts in the last decades. However, many climate records like, e.g., North Italian precipitation and river discharge records, indicate that significant decadal variability is often superposed or even dominates long-term hydrological trends. The capability to accurately predict such decadal changes is, therefore, of utmost environmental and social importance. Here, we present a twofold decadal forecast of Po River (Northern Italy) discharge obtained with a statistical approach consisting of the separate application and cross-validation of autoregressive models and neural networks. Both methods are applied to each significant variability component extracted from the raw discharge time series using Singular Spectrum Analysis, and the final forecast is obtained by merging the predictions of the individual components. The obtained 25-year forecasts robustly indicate a prominent dry period in the late 2020s/early 2030s. Our prediction provides information of great value for hydrological management, and a target for current and future near-term numerical hydrological predictions

Robust decadal hydroclimate predictions for northern Italy based on a twofold statistical approach

The Mediterranean area belongs to the regions most exposed to hydroclimatic changes, with a likely increase in frequency and duration of droughts in the last decades. However, many climate records like, e.g., North Italian precipitation and river discharge records, indicate that significant decadal variability is often superposed or even dominates long-term hydrological trends. The capability to accurately predict such decadal changes is, therefore, of utmost environmental and social importance. Here, we present a twofold decadal forecast of Po River (Northern Italy) discharge obtained with a statistical approach consisting of the separate application and cross-validation of autoregressive models and neural networks. Both methods are applied to each significant variability component extracted from the raw discharge time series using Singular Spectrum Analysis, and the final forecast is obtained by merging the predictions of the individual components. The obtained 25-year forecasts robustly indicate a prominent dry period in the late 2020s/early 2030s. Our prediction provides information of great value for hydrological management, and a target for current and future near-term numerical hydrological predictions

Why the 2022 Po River drought is the worst in the past two centuries

The causes of recent hydrological droughts and their future evolution under a changing climate are still poorly understood. Banking on a 216-year river flow time series at the Po River outlet, we show that the 2022 hydrological drought is the worst event (30% lower than the second worst, with a six-century return period), part of an increasing trend in severe drought occurrence. The decline in summer river flows (−4.14 cubic meters per second per year), which is more relevant than the precipitation decline, is attributed to a combination of changes in the precipitation regime, resulting in a decline of snow fraction (−0.6% per year) and snowmelt (−0.18 millimeters per day per year), and to increasing evaporation rate (+0.013 cubic kilometers per year) and irrigated areas (100% increment from 1900). Our study presents a compelling case where the hydrological impact of climate change is exacerbated by local changes in hydrologic seasonality and water use

Detailed study of the microwave emission of the supernova remnant 3C 396

We have observed the supernova remnant 3C~396 in the microwave region using the Parkes 64-m telescope. Observations have been made at 8.4 GHz, 13.5 GHz, and 18.6 GHz and in polarisation at 21.5 GHz. We have used data from several other observatories, including previously unpublished observations performed by the Green Bank Telescope at 31.2 GHz, to investigate the nature of the microwave emission of 3C 396. Results show a spectral energy distribution dominated by a single component power law emission with $\alpha=(-0.364 \pm 0.017)$. Data do not favour the presence of anomalous microwave emission coming from the source. Polarised emission at 21.5 GHz is consistent with synchrotron-dominated emission. We present microwave maps and correlate them with infrared (IR) maps in order to characterise the interplay between thermal dust and microwave emission. IR vs. microwave TT plots reveal poor correlation between mid-infrared and microwave emission from the core of the source. On the other hand, a correlation is detected in the tail emission of the outer shell of 3C 396, which could be ascribed to Galactic contamination.Comment: published in MNRA

Reply to Comment on: Hawking radiation from ultrashort laser pulse filaments

A comment by R. Schutzhold et al. raises possible concerns and questions regarding recent measurements of analogue Hawking radiation. We briefly reply to the opinions expressed in the comment and sustain that the origin of the radiation may be understood in terms of Hawking emission

Oxidative Stress Markers to Investigate the Effects of Hyperoxia in Anesthesia

Oxygen (O-2) is commonly used in clinical practice to prevent or treat hypoxia, but if used in excess (hyperoxia), it may act as toxic. O-2 toxicity arises from the enhanced formation of Reactive Oxygen Species (ROS) that exceed the antioxidant defenses and generate oxidative stress. In this study, we aimed at assessing whether an elevated fraction of inspired oxygen (FiO(2)) during and after general anesthesia may contribute to the unbalancing of the pro-oxidant/antioxidant equilibrium. We measured five oxidative stress biomarkers in blood samples from patients undergoing elective abdominal surgery, randomly assigned to FiO(2) = 0.40 vs. 0.80: hydroperoxides, antioxidants, nitrates and nitrites (NOx), malondialdehyde (MDA), and glutathionyl hemoglobin (HbSSG). The MDA concentration was significantly higher 24 h after surgery, and the body antioxidant defense lower, in the FiO(2) = 0.80 group with respect to both the FiO(2) = 0.40 group and the baseline values (p <= 0.05, Student's t-test). HbSSG in red blood cells was also higher in the FiO(2) = 0.80 group at the end of the surgery. NOx was higher in the FiO(2) = 0.80 group than the FiO(2) = 0.40 group at t = 2 h after surgery. MDA, the main end product of the peroxidation of polyunsaturated fatty acids directly influenced by FiO(2), may represent the best marker to assess the pro-oxidant/antioxidant equilibrium after surgery