Modelling distribution and fate of coralligenous habitat in the Northern Adriatic Sea under a severe climate change scenario

Due to their well-acknowledged capability in predicting habitat distributions, Habitat Suitability Models (HSMs) are particularly useful for investigating ecological patterns variations under climate change scenarios. The shallow coastal regions of the Northern Adriatic Sea, a sub-basin of the Mediterranean Sea, are studded with coralligenous outcrops recognized as important biodiversity hotspots exposed to the effects of climate change. In this research, we investigate the distributions of the Northern Adriatic Sea coralligenous habitats characterized by diverse species assemblages differently influenced by environmental factors, and provide a projection of how these might be impacted by climate change. Two models (Random Forest and MaxEnt), populated with occurrence data gathered from previous publications, environmental parameters’ from online databases (CMEMS, Bio-Oracle), and a set of dedicated ocean model simulations, are applied in recent past conditions and under a future severe climate change scenario (RCP 8.5). The model performance metrics confirm the ability of both approaches for predicting habitat distribution and their relationship with environmental conditions. The results show that salinity, temperature, and nitrate concentration are generally the most relevant variables in affecting the coralligenous outcrops distribution. The environmental variations projected under climate change conditions are expected to favour the spreading of opportunistic organisms, more tolerant to stressful conditions, at the expense of more vulnerable species. This will result in a shift in the distribution of these habitats, with a consequent potential loss of biodiversity in the Northern Adriatic Sea

Utjecaj olujnog vjetra na Jadransko more u uvjetima klimatskih promjena

In this work we assess the quality of the wind fields provided over the Adriatic Sea by the Regional Climate Model COSMO-CLM with reference to a control (CTR) period from 1971 to 2000 and to a future period from 2071 to 2100 under IPCC RCP 8.5 scenario (SCE), focusing on the implications for wave climate characterisation. Model skills have been assessed by comparing CTR results in terms of gross statistical properties and storm features against wind data from coastal observatories along the whole Italian Adriatic coast, showing a satisfactory capability of capturing the main features of mean observed seasonal variability. Significant achievements with reference to existing climatological models have been observed especially in terms of wind directionality, with unprecedented performances in reproducing the bimodal dominance of Bora (from northeast) and Sirocco (from southeast) in the northern basin, and the typical patterns of Bora jets flowing from the mountain ridges enclosing the Adriatic Sea on its eastern side. Future projections generally confirm the tendency to a decreasing energy trend envisaged by previous studies, with a more marked effect for extreme events in the northern basin. Based on the comparison between climatological wind fields and the results of a SWAN wave model run forced by COSMO-CLM, we also define and test a criterion for a rapid identification of some relevant case studies for dedicated wave modelling experiments, without the need of running entire climatological wave simulations. This permits to focus the analysis of climatological oceanographic extreme events to a limited number of selected cases, allowing remarkable saving of computational effort especially if an ensemble approach is desired.U ovom radu ocjenjujemo kvalitetu polja vjetra nad Jadranskim morem dobivenog primjenom Regionalnog klimatskog modela COSMO-CLM za kontrolno razdoblje (CTR) od 1971. do 2000. i za buduće razdoblje od 2071. do 2100. uz pretpostavku klimatskog scenarija IPCC RCP 8.5 (SCE), s posebnim osvrtom na posljedice za valnu klimu. Kvaliteta modela procijenjena je usporedbom njegovih rezultata za CTR-a s podacima vjetra s obalnih opservatorija duž cijelog talijanskog dijela jadranske obale na temelju ukupnih statističkih i olujnih svojstava. Usporedba je pokazala zadovoljavajuće rezultate modela pri reproduciranju glavnih obilježja srednje opažene sezonske varijabilnosti. Značajna unapređenja u odnosu na postojeće klimatske modele dobivena su posebice u reproduciranju smjera vjetra, kao i pri uspješnoj reprodukciji bimodalne dominacije bure (sa sjeveroistoka) i juga (s jugoistoka) u sjevernom bazenu, te tipičnim obrascima bure s jakim intenzitetima ispred planinskih prijevoja duž istočne obale Jadranskoga mora. Buduće projekcije općenito potvrđuju negativni trend energije predviđen i prethodnim studijama, s izrazitijim učinkom na ekstremne događaje u sjevernom bazenu. Na temelju usporedbe klimatoloških valnih polja i rezultata valnog modela SWAN forsiranog izlaznim poljima COSMO-CLM modela, definirani i testirani su kriteriji za brzu identifikaciju relevantnih situacija u modeliranju valova bez potrebe za izvođenjem cijele klimatološke simulacije valova. To dozvoljava da se analiza klimatoloških oceanografskih ekstremnih događaja usredotoči na ograničeni broj odabranih slučajeva, čime se omogućava značajna ušteda računalnih resursa pogotovo ako se želi primjeniti ansambl modela

Analysis of extreme events over Mediterranean sea with coupled numerical models

Questa tesi studia l’applicazione di simulazioni numeriche relative ad eventi estremi, sia atmosferici che oceanici, che si verificano nel bacino del Mediterraneo e che sono fortemente influenzati dall'interazione aerea-mare. Nella prima fase di questo lavoro viene proposta la caratterizzazione fisica degli eventi studiati. I fenomeni studiati sono: i) un evento di Cold Air Outbreak (CAO) avvenuto nell'inverno del 2012 nell'area del Mediterraneo centrale, e in particolare nel nord dell'Italia; ii) un evento di Dense Waters Formation (DWF) prodotta da questo evento CAO; e iii) un evento di "Tropical-Like Cyclone" (TLC) (chiamato "ROLF") che si è sviluppato sulle isole Baleari tra il 6 e il 9 novembre 2011. Inoltre vengono proposti i risultati preliminari di uno studio su un Flood Flash formato sulla Laguna di Venezia. Discuteremo le caratteristiche fisiche che governano questi fenomeni, in particolare l'interazione oceano-atmosfera. Dopo aver descritto questi fenomeni, proponiamo alcune considerazioni sulle applicazioni numeriche necessarie per una corretta simulazione di questi fenomeni, basandoci principalmente su tre approcci numerici. Il primo approccio numerico utilizzato è del tipo "Uncoupled", che consiste nell'uso di modelli atmosferici non accoppiati con modelli oceanici ricavano i dati di SST da datasets satellitari. Il secondo approccio utilizzato si riferisce all'uso di modelli accoppiati di atmosfera-oceano, mentre il terzo presenta l'accoppiamento completo tra atmosfera-oceano ed onde. Lo scopo di queste tecniche di modellizzazione è cercare di descrivere con maggiore precisione i flussi di momento e di calore che si esplicano all’interfaccia aria-mare e che caratterizzano e guidano l’evoluzione di alcuni fenomeni estremi, atmosferici ed oceanici. I risultati mostrano che l'uso di modelli accoppiati fornisce risultati migliori se comparato ad applicazioni non accoppiate, suggerendo spunti significativi per lavori futuri anche nel campo climatologico.This thesis is the result of the work carried out in the three years of course, dealing with the issue of the application of numerical simulations related to extreme events, both atmospheric and oceanic, that appear over the Mediterranean basin and that are strongly influenced by the air-sea interaction. In the first phase of this work the physical characterization of the studied events is proposed. The phenomena studied are i) a case of Cold Air Outbreak (CAO) formed in the winter of 2012 on the central Mediterranean area, and in particular in the north of Italy; ii) a Dense Waters Formation (DWF) produced by this CAO event; and iii) one event of "Tropical-Like Cyclone" (TLC) (called “ROLF”) that developed on the Balearic Islands between the 6th and the 9th of November 2011. Moreover, preliminary results about a Flash Flood formed over the Venice Lagoon are showed in the end of this manuscript. We will discuss the physical characteristics that govern these phenomena, in particular the interaction between sea and atmosphere. After describing and studying the above mentioned phenomena, we propose some considerations regarding the numerical applications that are needed in order to obtain better results. The modeling techniques used for this thesis are mainly three. The first approach used is a classical "Uncoupled", which consists in the use of atmospheric models uncoupled to ocean models and wave models that exploit SST satellite data. The second approach used refers to the use of "Coupled" ocean-atmosphere models, and the third presents the ocean-wave atmosphere coupling. The purpose of these modeling techniques is to try to describe accurately the momentum and heat fluxes that appear at the air-sea interface, and that characterize, very often, some atmospheric and oceanic phenomena. Results show that the use of coupled models provide improved results, having this approach a direct impact mostly on some heat and momentum fluxes and the SST evolution, fundamental in some applications. Moreover, other indirect implications brought along by the use of coupled models, that are often important at the basin scale and regarding also the case of deep marine ventilation, are presented and discussed (Benetazzo et al., 2013, Carniel et al., 2016, Ricchi et al., 2016, Ricchi et al., 2017, Bonaldo et al., 2017)

DELWAVE 1.0

We propose a new point-prediction model, the DEep Learning WAVe Emulating model (DELWAVE), which successfully emulates the behaviour of a numerical surface ocean wave model (Simulating WAves Nearshore, SWAN) at a sparse set of locations, thus enabling numerically cheap large-ensemble prediction over synoptic to climate timescales. DELWAVE was trained on COSMO-CLM (Climate Limited-area Model) and SWAN input data during the period of 1971–1998, tested during 1998–2000, and cross-evaluated over the far-future climate time window of 2071–2100. It is constructed from a convolutional atmospheric encoder block, followed by a temporal collapse block and, finally, a regression block. DELWAVE reproduces SWAN model significant wave heights with a mean absolute error (MAE) of between 5 and 10 cm, mean wave directions with a MAE of 10–25°, and a mean wave period with a MAE of 0.2 s. DELWAVE is able to accurately emulate multi-modal mean wave direction distributions related to dominant wind regimes in the basin. We use wave power analysis from linearised wave theory to explain prediction errors in the long-period limit during southeasterly conditions. We present a storm analysis of DELWAVE, employing threshold-based metrics of precision and recall to show that DELWAVE reaches a very high score (both metrics over 95 %) of storm detection. SWAN and DELWAVE time series are compared to each other in the end-of-century scenario (2071–2100) and compared to the control conditions in the 1971–2000 period. Good agreement between DELWAVE and SWAN is found when considering climatological statistics, with a small (≤ 5 %), though systematic, underestimate of 99th-percentile values. Compared to control climatology over all wind directions, the mismatch between DELWAVE and SWAN is generally small compared to the difference between scenario and control conditions, suggesting that the noise introduced by surrogate modelling is substantially weaker than the climate change signal

Dynamical Downscaling in Seasonal Climate Forecasts: Comparison between RegCM- and WRF-Based Approaches

The purpose of the present study is to assess the large-scale signal modulation produced by two dynamically downscaled Seasonal Forecasting Systems (SFSs) and investigate if additional predictive skill can be achieved, compared to the driving global-scale Climate Forecast System (CFS). The two downscaled SFSs are evaluated and compared in terms of physical values and anomaly interannual variability. Downscaled SFSs consist of two two-step dynamical downscaled ensembles of NCEP-CFSv2 re-forecasts. In the first step, the CFS field is downscaled from 100 km to 60 km over Southern Europe (D01). The second downscaling, driven by the corresponding D01, is performed at 12 km over Central Italy (D02). Downscaling is performed using two different Regional Climate Models (RCMs): RegCM v.4 and WRF 3.9.1.1. SFS skills are assessed over a period of 21 winter seasons (1982–2002), by means of deterministic and probabilistic approach and with a metric specifically designed to isolate downscaling signal over different percentiles of distribution. Considering the temperature fields and both deterministic and probabilistic metrics, regional-scale SFSs consistently improve the original CFS Seasonal Anomaly Signal (SAS). For the precipitation, the added value of downscaled SFSs is mainly limited to the topography driven refinement of precipitation field, whereas the SAS is mainly “inherited” by the driving CFS. The regional-scale SFSs do not seem to benefit from the second downscaling (D01 to D02) in terms of SAS improvement. Finally, WRF and RegCM show substantial differences in both SAS and climatologically averaged fields, highlighting a different impact of the common SST driving field

Considerazioni sul carcinoma metacrono del colon e del retto.

Cod. CNR P 0000237

Climate Change and Military Power: Hunting for Submarines in the Warming Ocean (Spring 2024)

Climate change will have significant effects on military power, capabilities, effectiveness, and employment. Yet, scholars have paid little attention to this topic. We address this gap by investigating the effects of changing ocean conditions on anti-submarine warfare. Anti-submarine warfare capabilities exploit various physical phenomena to detect enemy submarines, principally underwater sound propagation. Underwater sound propagation depends on factors influenced by climate change, such as water temperature and salinity. Through ocean-acoustic simulations, we estimate the effect of climate change on the detection range of enemy submarines in the North Atlantic and in the Western Pacific. Our results show that, in most areas, the range of detection through underwater acoustics is contracting due to climate change.LBJ School of Public Affair