PIERO LIONELLO | University of Salento (original) (raw)
Papers by PIERO LIONELLO
Frontiers in Marine Science, Dec 15, 2021
The fate of the beaches around the world has paramount importance as they are one of the main ass... more The fate of the beaches around the world has paramount importance as they are one of the main assets for touristic activities and act as a natural barrier for coastal protection in front of marine storms. Climate change could put them at risk as sea levels rise and changes in the wave characteristics may dramatically modify their shape. In this work, a new methodology has been developed to determine the flooding of sandy beaches due to changes in sea level and waves. The methodology allows a cost-effective and yet accurate estimation of the wave runup for a wide range of beach equilibrium profiles and for different seagrass coverage. This, combined with regional projections of sea level and wave evolution, has allowed a quantification of the future total water level and coastline retreat for 869 beaches across the Balearic Islands for the next decades as a function of greenhouse gases emission scenario. The most pessimistic scenario (RCP8.5) at the end of the century yields an averaged percentage of flooded area of 66% under mean conditions which increases up to 86% under extreme conditions. Moreover, 72 of the 869 beaches of the region would permanently disappear while 314 would be completely flooded during storm episodes. Under a moderate scenario of emissions (RCP4.5), 37 beaches would permanently disappear while 254 would disappear only during storm episodes. In both cases, the average permanent loss of beach surface at the end of the century would be larger than 50%, rising over 80% during storm conditions. The results obtained for the Balearic Islands can be extrapolated to the rest of the Mediterranean as the beaches in all the regions have similar characteristics and will be affected by similar changes in sea level and wave climate. These projections indicate that adaptation plans for beach areas should be put in place as soon as possible.
VENEDIG ITALY ESA STUDY CONTRACT REPORT No ESA Study Contract Report will be accepted unless this... more VENEDIG ITALY ESA STUDY CONTRACT REPORT No ESA Study Contract Report will be accepted unless this sheet is inserted at the beginning of each volume of the Report ESA CONTRACT NO 6875/87/ HGE I (SC) SUBJECT Development of a satellite SAR image spectra and altimeter \'laVe height data assimilation system for ERS-l
Ocean Engineering, Sep 1, 2017
Harbours are essential infrastructures for economic activity that are susceptible to impacts from... more Harbours are essential infrastructures for economic activity that are susceptible to impacts from climate change driven processes, like sea level rise (SLR), or alterations in wave patterns. In this paper, the impact of climate change on wave agitation in ports (oscillations due to wind waves) and, therefore, on port operability is analyzed. This is carried out through a numerical model suite, considering the RCP8.5 scenario to project changes in wave fields, and three values of SLR. The study is particularized for the port of Barcelona (NW Mediterranean), but the used methodology can be applied to other harbours. Results suggest that changes due only to waves will be minimal and with a general trend to slightly decrease wave agitation. On the contrary, the effect of SLR and the associated increase of water depth will favor the penetration of waves within the harbour, leading to a certain reduction of port operability, the magnitude of which will depend on the SLR value. However, the complexity of wave patterns within the harbours, due to multiple reflections of waves on port structures, implies that the reduction of operability strongly varies according to the position and orientation of the berthing zones inside the harbour.
Atmospheric Chemistry and Physics, Feb 4, 2019
The First Mediterranean Assessment Report (MAR1) prepared by the independent network of Mediterra... more The First Mediterranean Assessment Report (MAR1) prepared by the independent network of Mediterranean Experts on Climate and environmental Change (MedECC) founded in 2015, is now published. MAR1 assesses the best available scientific knowledge on climate and environmental change and associated risks in the Mediterranean Basin in order to render it accessible to policymakers, stakeholders and citizens. The report includes a Summary for Policymakers (SPM), which comprises the key messages of the MAR1. The report has been written by 190 scientists from 25 countries, all contributing in individual capacity and without financial compensation. The UNEP/MAP – Barcelona Convention Secretariat, through its Plan Bleu Regional Activity Center, and the Secretariat of the Union for the Mediterranean work in partnership to support MedECC, and to contribute to establish a sound and transparent scientific assessment process.
This study describes the impact of climate change on rainfall probability over three Mediterranea... more This study describes the impact of climate change on rainfall probability over three Mediterranean areas: (1) North-Western coast, (2) South Italy and (3) central part of the Mediterranean sea. The effect of adopting model version with different horizontal resolutions is analyzed. Two climate representative concentration pathways (rcp4.5 and rcp8.5) three different grid resolutions (0.11, 0.44 e 0.75 degs) are considered. The first two simulations (0.11. and 0.44degs resolution) have been carried out using COSMOMED, which is a coupled atmosphere-ocean system consisting of the regional climate model COSMO-CLM and the ocean-sea model NEMO. The low resolution (0.75 degs) simulation has been carried out with a global AOGCM model, named CMCC-CM, whose results have been used to force the regional model simulations. High resolution simulations are still in progress (presently the year 2090 has been reached). Therefore, this abstract is limited to comparing the time slice 2021-2050 (warm pe...
The severity of future hazards along the coastlines depends on sea level rise, vertical land moti... more The severity of future hazards along the coastlines depends on sea level rise, vertical land motion and intensity of marine storminess. This study describes the effect of climate change on this last factor at the coast of the Mediterranean Sea. Specifically, we have computed the distribution of large surges and wave heights along the Mediterranean Sea coastline in the present condition and in a future climate scenario. This analysis is obviously important for evaluation of coastal risks and management of coastal defences (e.g. Nichols & Hoozemans, 1996).
Global and Planetary Change, 2017
Geophysical Research Letters, 2017
The Hadley circulation (HC) extent and strength are analyzed in a wide range of simulated climate... more The Hadley circulation (HC) extent and strength are analyzed in a wide range of simulated climates from the Last Glacial Maximum to global warming scenarios. Motivated by HC theories, we analyze how the HC is influenced by the subtropical stability, the near‐surface meridional potential temperature gradient, and the tropical tropopause level. The subtropical static stability accounts for the bulk of the HC changes across the simulations. However, since it correlates strongly with global mean surface temperature, most HC changes can be attributed to global mean surface temperature changes. The HC widens as the climate warms, and it also weakens, but only robustly so in the Northern Hemisphere. On the other hand, the Southern Hemisphere strength response is uncertain, in part because subtropical static stability changes counteract meridional potential temperature gradient changes to various degrees in different models, with no consensus on the response of the latter to global warming.
Natural Hazards and Earth System Sciences, 2013
Natural Hazards and Earth System Sciences, Feb 20, 2014
There is an increasing interest of scientists on climate extremes. A progressively larger number ... more There is an increasing interest of scientists on climate extremes. A progressively larger number of papers dealing with climate issues have been produced in the past 15 yr, and those dealing with extremes have increased at an even faster pace. The number of papers on extremes in the Mediterranean follows this overall trend and confirms how extremes are perceived to be important by the scientific community and by society. This special issue (which is mainly related to activities of the MedCLIVAR (Mediterranean CLImate VARiability and Predictability) and CIRCE (Climate Change and Impact Research: the Mediterranean Environment) projects), contains thirteen papers that are representative of current research on extremes in the Mediterranean region. Five have precipitation as its main target, four temperature (one paper addresses both variables), and two droughts; the remaining papers consider sea level, winds and impacts on society. Results are quite clear concerning climate evolution toward progressively hotter temperature extremes, but more controversial for precipitation, though in the published literature there are indications for a future increasing intensity of hydrological extremes (intense precipitation events and droughts). Scenario simulations suggest an attenuation of extreme storms, winds, waves and surges, but more results are requested for confirming this future change.
Climate Research, 2003
This study attempts to estimate the effect of CO 2 doubling on the frequency and intensity of hig... more This study attempts to estimate the effect of CO 2 doubling on the frequency and intensity of high wind waves and storm-surge events in the Adriatic Sea. The meteorological forcings were derived from two 30-yr-long time-slice experiments that simulated the global atmospheric circulation in the present and the doubled-CO 2 climate scenarios. These time-slice experiments were carried out by the Danish Meteorological Institute using the ECHAM-4 model at T106 resolution. Unfortunately, the resolution of the T106 wind is inadequate for simulation of the wave field and the storm surge in the Adriatic Sea, and it results in a gross underevaluation of extreme events. In this study, regional surface wind fields have been derived from T106 sea-level-pressure fields by statistical downscaling. Downscaled wind fields have been used to force a wave and an ocean model during the two 30-yrlong simulations. The downscaled wind fields produce a large improvement with respect to the T106 fields, but a systematic underestimation with respect to the observed wave height and surge levels remains present. This shortcoming of the analysis might prevent identification of very intense events. Consequently, extreme-value analysis of the results of the present climate simulation produces values lower than observed, and obviously the same systematic bias is expected in the evaluation of the future climate. Some caution is therefore necessary in the interpretation of the results of this study. Nonetheless, the comparison between the present and future climate simulations shows no substantial change in the extreme surge level and a decrease in the extreme wave height.
Physics And Chemistry Of The Earth, Parts A/b/c, 2012
This paper discusses present characteristics and trends of severe marine storminess in the Northe... more This paper discusses present characteristics and trends of severe marine storminess in the Northern Adriatic. It merges oceanographic and meteorological aspects by considering storm surges, wind waves and the atmospheric cyclones that cause them. The paper introduces these three processes and the different role of south-easterly (Sirocco) and easterly (Bora) wind regimes. The specific characteristics of cyclones producing severe marine storms in terms of location where cyclogenesis occurs, trajectories and intensity, are compared with those of generic cyclones crossing northern Italy. It is shown that cyclones producing high waves and surges in most cases have different characteristics and their lists overlap only partially. However, both high wave and surge events have a similar annual cycle, with maximum activity in November and hardly any event in summer (June–July–August). The trends of severe high wave and surge events are discussed (various thresholds are considered) and they are shown to be broadly consistent. Timeseries, which show large inter-annual variability and very little overall tendencies on multi-decadal time scale, suggest progressively milder storms during the second half of the 20th century.
Journal of Geophysical Research, 1989
In the next decade a wealth of ocean surface data will become available through the launch of sat... more In the next decade a wealth of ocean surface data will become available through the launch of satellites such as ERS 1. We discuss the problem of how to make optimal use of this data. We have investigated the benefits of having a coupled wind-wave analysis over the oceans for quality assessment of satellite data, for monitoring the performance of the algorithms (e.g., for the scatterometer), and for producing consistent wind and wave analyses. Using a reliable wave prediction scheme, the WAM model, we show how to cross validate altimeter wave height with scatterometer data and how to construct an analyzed wave model spectrum from the altimeter wave height. The analyzed wave spectrum may be cross validated with the synthetic aperture radar image spectrum. Implications for improvement of, for example, the Seasat scatterometer algorithm are pointed out. 1. INTRODUCTION This paper is a presentation of results of a study on the feasibility of using altimeter wave height data from a satellite in a real time wave data assimilation scheme. The main topics are the potential this offers for quality assurance and validation of scatterometer data and synthetic aperture radar (SAR) data as well as cross validation of these data sources. The wave data assimilation scheme we constructed uses first-guess wave fields from the Wave Model (WAM) model, the first model that explicitly solves the energy balance equation for the two-dimensional wave spectrum [WAM Development and Implementation (WAMDI) group, 1988]. Since global wind fields [Anderson et al., 1987] and altimeter data were available during part (September 6, to September 17, 1978) of the Seasat period, it was decided to experiment with assimilations of Seasat altimeter data in order to explore these main topics. Waves are generated by the wind, and it is well known that wave prediction models are sensitive to errors in the wind field [Janssen et al., 1984]. The questions of the impact of the scatterometer data on wave prediction and the use of wave data for wind analysis are therefore of interest. We performed two hindcast experiments with the WAM model, one forced by analyzed wind fields without scatterometer data and one forced by analyzed wind fields including scatterometer data. The results of this study are reported in section 2. An investigation of the differences in wave height between the two experiments confirmed the conclusion of Anderson et al. [1987] that scatterometer data has impact in the southern hemisphere and occasionally in the tropics. Since a wave model is such a "sensitive measuring device" of the wind field, the question of the quality of scatterometer data may be addressed. To that end we collocated modeled wave height of the two experiments with
On 12 November 2019, an exceptional flood event occurred in Venice, second only to the one that h... more On 12 November 2019, an exceptional flood event occurred in Venice, second only to the one that had occurred on 4 November 1966. The event caused the flooding of about 90% of the streets in the historic centre and the sea level reached a value of 189 cm compared to the local mean-sea-level datum. Subsequent analysis of the meteorological event highlighted the contributions at different temporal and spatial scales. A sub-synoptic cyclone, centred in the Tyrrhenian Sea, caused a strong Sirocco wind along the entire Adriatic basin, with a fairly typical atmospheric configuration. However, embedded in the first cyclone, a second meso-beta scale cyclone developed and moved in the north-westward direction over the Adriatic Sea along the Italian coast. This cyclone had a speed of about 12 m/s, very close to the speed of the shallow water waves for the depth of the northern Adriatic basin. The perturbation then triggered a Proudman resonance, as confirmed by the numerical simulations, and caused a meteotsunami-like wave that affected the north-western coasts of the Adriatic Sea. Through model simulations, we have estimated that the mesoscale cyclone contributed about 40 cm, of which about 40% may be attributed to the air-pressure forcing, amplified through the Proudman resonance, and the rest to the wind forcing influencing both the open Adriatic Sea and the shallow Venetian lagoon. Finally, we have also analysed the propagation and transformation of the perturbation upon its entrance into the Venetian lagoon. This work is part of the COST action CA19109 MEDCYCLONES (European Network for Mediterranean Cyclones in weather and climate) and the Interreg Italy-Croatia STREAM project (Strategic development of flood management, project ID 10249186).
ABSTRACT This study considers intense precipitation events at the Mediterranean coast characteriz... more ABSTRACT This study considers intense precipitation events at the Mediterranean coast characterized as sequences of days with continuous precipitation and large accumulated values at the end of the rainy day sequence. Long periods with multiple precipitation maxima are split in sets of shorter events. The list of cyclones are provided by an tracking algorithm applied to the ERA-40 (ECMWF Re-Analysis) dataset for the period 1958-2002. Data for the analysis of daily precipitation are provided by the ECA (European Climate Assessment, hosted at Royal Netherlands Meteorological Institute, KNMI) dataset. The presence of cyclones when intense precipitation is recorded shows a clear link between the two processes and the link emerging from this analysis is much stronger that that deriving from the analysis of individual very rainy days. This analysis also shows that there is link between the precipitations events and the intensity of the cyclones, their velocity, and the amount of water vapor in the middle troposphere.
Global and Planetary Change, Apr 1, 2017
Abstract The evolution of the upper water column in the Mediterranean Sea during more than 60 yea... more Abstract The evolution of the upper water column in the Mediterranean Sea during more than 60 years is reconstructed in terms of few parameters describing the mixed layer and the seasonal thermocline. The analysis covers the period 1945–2011 using data from three public sources: MEDAR-MEDATLAS, World Ocean Database, MFS-VOS program. Five procedures for estimating the mixed layer depth are described, discussed and compared using the 20-year long time series of temperature profiles of the DYFAMED station in the Ligurian Sea. On this basis the so-called three segments profile model (which approximates the upper water column with three segments representing mixed layer, thermocline and deep layer) has been selected for a systematic analysis at Mediterranean scale. A widespread increase of the thickness and temperature of the mixed layer, increase of the depth and decrease of the temperature of the thermocline base have been observed in summer and autumn during the recent decades. It is shown that positive temperature extremes of the mixed layer and of its thickness are potential drivers of the mass mortalities of benthic invertebrates documented since 1983. Hotspots of mixed layer anomalies have been also identified. These results refine previous analyses showing that ongoing and future warming of upper Mediterranean is likely to increase mass mortalities by producing environmental conditions beyond the limit of tolerance of some benthic species.
Physics And Chemistry Of The Earth, Parts A/b/c, 2012
An analysis of the climate change signal for seasonal temperature and precipitation over the Nort... more An analysis of the climate change signal for seasonal temperature and precipitation over the Northern Adriatic region is presented here. We collected 43 regional climate simulations covering the target area, including experiments produced in the context of the PRUDENCE and ENSEMBLES projects, and additional experiments produced by the Swedish Meteorological and Hydrological Institute. The ability of the models to simulate
Frontiers in Marine Science, Dec 15, 2021
The fate of the beaches around the world has paramount importance as they are one of the main ass... more The fate of the beaches around the world has paramount importance as they are one of the main assets for touristic activities and act as a natural barrier for coastal protection in front of marine storms. Climate change could put them at risk as sea levels rise and changes in the wave characteristics may dramatically modify their shape. In this work, a new methodology has been developed to determine the flooding of sandy beaches due to changes in sea level and waves. The methodology allows a cost-effective and yet accurate estimation of the wave runup for a wide range of beach equilibrium profiles and for different seagrass coverage. This, combined with regional projections of sea level and wave evolution, has allowed a quantification of the future total water level and coastline retreat for 869 beaches across the Balearic Islands for the next decades as a function of greenhouse gases emission scenario. The most pessimistic scenario (RCP8.5) at the end of the century yields an averaged percentage of flooded area of 66% under mean conditions which increases up to 86% under extreme conditions. Moreover, 72 of the 869 beaches of the region would permanently disappear while 314 would be completely flooded during storm episodes. Under a moderate scenario of emissions (RCP4.5), 37 beaches would permanently disappear while 254 would disappear only during storm episodes. In both cases, the average permanent loss of beach surface at the end of the century would be larger than 50%, rising over 80% during storm conditions. The results obtained for the Balearic Islands can be extrapolated to the rest of the Mediterranean as the beaches in all the regions have similar characteristics and will be affected by similar changes in sea level and wave climate. These projections indicate that adaptation plans for beach areas should be put in place as soon as possible.
VENEDIG ITALY ESA STUDY CONTRACT REPORT No ESA Study Contract Report will be accepted unless this... more VENEDIG ITALY ESA STUDY CONTRACT REPORT No ESA Study Contract Report will be accepted unless this sheet is inserted at the beginning of each volume of the Report ESA CONTRACT NO 6875/87/ HGE I (SC) SUBJECT Development of a satellite SAR image spectra and altimeter \'laVe height data assimilation system for ERS-l
Ocean Engineering, Sep 1, 2017
Harbours are essential infrastructures for economic activity that are susceptible to impacts from... more Harbours are essential infrastructures for economic activity that are susceptible to impacts from climate change driven processes, like sea level rise (SLR), or alterations in wave patterns. In this paper, the impact of climate change on wave agitation in ports (oscillations due to wind waves) and, therefore, on port operability is analyzed. This is carried out through a numerical model suite, considering the RCP8.5 scenario to project changes in wave fields, and three values of SLR. The study is particularized for the port of Barcelona (NW Mediterranean), but the used methodology can be applied to other harbours. Results suggest that changes due only to waves will be minimal and with a general trend to slightly decrease wave agitation. On the contrary, the effect of SLR and the associated increase of water depth will favor the penetration of waves within the harbour, leading to a certain reduction of port operability, the magnitude of which will depend on the SLR value. However, the complexity of wave patterns within the harbours, due to multiple reflections of waves on port structures, implies that the reduction of operability strongly varies according to the position and orientation of the berthing zones inside the harbour.
Atmospheric Chemistry and Physics, Feb 4, 2019
The First Mediterranean Assessment Report (MAR1) prepared by the independent network of Mediterra... more The First Mediterranean Assessment Report (MAR1) prepared by the independent network of Mediterranean Experts on Climate and environmental Change (MedECC) founded in 2015, is now published. MAR1 assesses the best available scientific knowledge on climate and environmental change and associated risks in the Mediterranean Basin in order to render it accessible to policymakers, stakeholders and citizens. The report includes a Summary for Policymakers (SPM), which comprises the key messages of the MAR1. The report has been written by 190 scientists from 25 countries, all contributing in individual capacity and without financial compensation. The UNEP/MAP – Barcelona Convention Secretariat, through its Plan Bleu Regional Activity Center, and the Secretariat of the Union for the Mediterranean work in partnership to support MedECC, and to contribute to establish a sound and transparent scientific assessment process.
This study describes the impact of climate change on rainfall probability over three Mediterranea... more This study describes the impact of climate change on rainfall probability over three Mediterranean areas: (1) North-Western coast, (2) South Italy and (3) central part of the Mediterranean sea. The effect of adopting model version with different horizontal resolutions is analyzed. Two climate representative concentration pathways (rcp4.5 and rcp8.5) three different grid resolutions (0.11, 0.44 e 0.75 degs) are considered. The first two simulations (0.11. and 0.44degs resolution) have been carried out using COSMOMED, which is a coupled atmosphere-ocean system consisting of the regional climate model COSMO-CLM and the ocean-sea model NEMO. The low resolution (0.75 degs) simulation has been carried out with a global AOGCM model, named CMCC-CM, whose results have been used to force the regional model simulations. High resolution simulations are still in progress (presently the year 2090 has been reached). Therefore, this abstract is limited to comparing the time slice 2021-2050 (warm pe...
The severity of future hazards along the coastlines depends on sea level rise, vertical land moti... more The severity of future hazards along the coastlines depends on sea level rise, vertical land motion and intensity of marine storminess. This study describes the effect of climate change on this last factor at the coast of the Mediterranean Sea. Specifically, we have computed the distribution of large surges and wave heights along the Mediterranean Sea coastline in the present condition and in a future climate scenario. This analysis is obviously important for evaluation of coastal risks and management of coastal defences (e.g. Nichols & Hoozemans, 1996).
Global and Planetary Change, 2017
Geophysical Research Letters, 2017
The Hadley circulation (HC) extent and strength are analyzed in a wide range of simulated climate... more The Hadley circulation (HC) extent and strength are analyzed in a wide range of simulated climates from the Last Glacial Maximum to global warming scenarios. Motivated by HC theories, we analyze how the HC is influenced by the subtropical stability, the near‐surface meridional potential temperature gradient, and the tropical tropopause level. The subtropical static stability accounts for the bulk of the HC changes across the simulations. However, since it correlates strongly with global mean surface temperature, most HC changes can be attributed to global mean surface temperature changes. The HC widens as the climate warms, and it also weakens, but only robustly so in the Northern Hemisphere. On the other hand, the Southern Hemisphere strength response is uncertain, in part because subtropical static stability changes counteract meridional potential temperature gradient changes to various degrees in different models, with no consensus on the response of the latter to global warming.
Natural Hazards and Earth System Sciences, 2013
Natural Hazards and Earth System Sciences, Feb 20, 2014
There is an increasing interest of scientists on climate extremes. A progressively larger number ... more There is an increasing interest of scientists on climate extremes. A progressively larger number of papers dealing with climate issues have been produced in the past 15 yr, and those dealing with extremes have increased at an even faster pace. The number of papers on extremes in the Mediterranean follows this overall trend and confirms how extremes are perceived to be important by the scientific community and by society. This special issue (which is mainly related to activities of the MedCLIVAR (Mediterranean CLImate VARiability and Predictability) and CIRCE (Climate Change and Impact Research: the Mediterranean Environment) projects), contains thirteen papers that are representative of current research on extremes in the Mediterranean region. Five have precipitation as its main target, four temperature (one paper addresses both variables), and two droughts; the remaining papers consider sea level, winds and impacts on society. Results are quite clear concerning climate evolution toward progressively hotter temperature extremes, but more controversial for precipitation, though in the published literature there are indications for a future increasing intensity of hydrological extremes (intense precipitation events and droughts). Scenario simulations suggest an attenuation of extreme storms, winds, waves and surges, but more results are requested for confirming this future change.
Climate Research, 2003
This study attempts to estimate the effect of CO 2 doubling on the frequency and intensity of hig... more This study attempts to estimate the effect of CO 2 doubling on the frequency and intensity of high wind waves and storm-surge events in the Adriatic Sea. The meteorological forcings were derived from two 30-yr-long time-slice experiments that simulated the global atmospheric circulation in the present and the doubled-CO 2 climate scenarios. These time-slice experiments were carried out by the Danish Meteorological Institute using the ECHAM-4 model at T106 resolution. Unfortunately, the resolution of the T106 wind is inadequate for simulation of the wave field and the storm surge in the Adriatic Sea, and it results in a gross underevaluation of extreme events. In this study, regional surface wind fields have been derived from T106 sea-level-pressure fields by statistical downscaling. Downscaled wind fields have been used to force a wave and an ocean model during the two 30-yrlong simulations. The downscaled wind fields produce a large improvement with respect to the T106 fields, but a systematic underestimation with respect to the observed wave height and surge levels remains present. This shortcoming of the analysis might prevent identification of very intense events. Consequently, extreme-value analysis of the results of the present climate simulation produces values lower than observed, and obviously the same systematic bias is expected in the evaluation of the future climate. Some caution is therefore necessary in the interpretation of the results of this study. Nonetheless, the comparison between the present and future climate simulations shows no substantial change in the extreme surge level and a decrease in the extreme wave height.
Physics And Chemistry Of The Earth, Parts A/b/c, 2012
This paper discusses present characteristics and trends of severe marine storminess in the Northe... more This paper discusses present characteristics and trends of severe marine storminess in the Northern Adriatic. It merges oceanographic and meteorological aspects by considering storm surges, wind waves and the atmospheric cyclones that cause them. The paper introduces these three processes and the different role of south-easterly (Sirocco) and easterly (Bora) wind regimes. The specific characteristics of cyclones producing severe marine storms in terms of location where cyclogenesis occurs, trajectories and intensity, are compared with those of generic cyclones crossing northern Italy. It is shown that cyclones producing high waves and surges in most cases have different characteristics and their lists overlap only partially. However, both high wave and surge events have a similar annual cycle, with maximum activity in November and hardly any event in summer (June–July–August). The trends of severe high wave and surge events are discussed (various thresholds are considered) and they are shown to be broadly consistent. Timeseries, which show large inter-annual variability and very little overall tendencies on multi-decadal time scale, suggest progressively milder storms during the second half of the 20th century.
Journal of Geophysical Research, 1989
In the next decade a wealth of ocean surface data will become available through the launch of sat... more In the next decade a wealth of ocean surface data will become available through the launch of satellites such as ERS 1. We discuss the problem of how to make optimal use of this data. We have investigated the benefits of having a coupled wind-wave analysis over the oceans for quality assessment of satellite data, for monitoring the performance of the algorithms (e.g., for the scatterometer), and for producing consistent wind and wave analyses. Using a reliable wave prediction scheme, the WAM model, we show how to cross validate altimeter wave height with scatterometer data and how to construct an analyzed wave model spectrum from the altimeter wave height. The analyzed wave spectrum may be cross validated with the synthetic aperture radar image spectrum. Implications for improvement of, for example, the Seasat scatterometer algorithm are pointed out. 1. INTRODUCTION This paper is a presentation of results of a study on the feasibility of using altimeter wave height data from a satellite in a real time wave data assimilation scheme. The main topics are the potential this offers for quality assurance and validation of scatterometer data and synthetic aperture radar (SAR) data as well as cross validation of these data sources. The wave data assimilation scheme we constructed uses first-guess wave fields from the Wave Model (WAM) model, the first model that explicitly solves the energy balance equation for the two-dimensional wave spectrum [WAM Development and Implementation (WAMDI) group, 1988]. Since global wind fields [Anderson et al., 1987] and altimeter data were available during part (September 6, to September 17, 1978) of the Seasat period, it was decided to experiment with assimilations of Seasat altimeter data in order to explore these main topics. Waves are generated by the wind, and it is well known that wave prediction models are sensitive to errors in the wind field [Janssen et al., 1984]. The questions of the impact of the scatterometer data on wave prediction and the use of wave data for wind analysis are therefore of interest. We performed two hindcast experiments with the WAM model, one forced by analyzed wind fields without scatterometer data and one forced by analyzed wind fields including scatterometer data. The results of this study are reported in section 2. An investigation of the differences in wave height between the two experiments confirmed the conclusion of Anderson et al. [1987] that scatterometer data has impact in the southern hemisphere and occasionally in the tropics. Since a wave model is such a "sensitive measuring device" of the wind field, the question of the quality of scatterometer data may be addressed. To that end we collocated modeled wave height of the two experiments with
On 12 November 2019, an exceptional flood event occurred in Venice, second only to the one that h... more On 12 November 2019, an exceptional flood event occurred in Venice, second only to the one that had occurred on 4 November 1966. The event caused the flooding of about 90% of the streets in the historic centre and the sea level reached a value of 189 cm compared to the local mean-sea-level datum. Subsequent analysis of the meteorological event highlighted the contributions at different temporal and spatial scales. A sub-synoptic cyclone, centred in the Tyrrhenian Sea, caused a strong Sirocco wind along the entire Adriatic basin, with a fairly typical atmospheric configuration. However, embedded in the first cyclone, a second meso-beta scale cyclone developed and moved in the north-westward direction over the Adriatic Sea along the Italian coast. This cyclone had a speed of about 12 m/s, very close to the speed of the shallow water waves for the depth of the northern Adriatic basin. The perturbation then triggered a Proudman resonance, as confirmed by the numerical simulations, and caused a meteotsunami-like wave that affected the north-western coasts of the Adriatic Sea. Through model simulations, we have estimated that the mesoscale cyclone contributed about 40 cm, of which about 40% may be attributed to the air-pressure forcing, amplified through the Proudman resonance, and the rest to the wind forcing influencing both the open Adriatic Sea and the shallow Venetian lagoon. Finally, we have also analysed the propagation and transformation of the perturbation upon its entrance into the Venetian lagoon. This work is part of the COST action CA19109 MEDCYCLONES (European Network for Mediterranean Cyclones in weather and climate) and the Interreg Italy-Croatia STREAM project (Strategic development of flood management, project ID 10249186).
ABSTRACT This study considers intense precipitation events at the Mediterranean coast characteriz... more ABSTRACT This study considers intense precipitation events at the Mediterranean coast characterized as sequences of days with continuous precipitation and large accumulated values at the end of the rainy day sequence. Long periods with multiple precipitation maxima are split in sets of shorter events. The list of cyclones are provided by an tracking algorithm applied to the ERA-40 (ECMWF Re-Analysis) dataset for the period 1958-2002. Data for the analysis of daily precipitation are provided by the ECA (European Climate Assessment, hosted at Royal Netherlands Meteorological Institute, KNMI) dataset. The presence of cyclones when intense precipitation is recorded shows a clear link between the two processes and the link emerging from this analysis is much stronger that that deriving from the analysis of individual very rainy days. This analysis also shows that there is link between the precipitations events and the intensity of the cyclones, their velocity, and the amount of water vapor in the middle troposphere.
Global and Planetary Change, Apr 1, 2017
Abstract The evolution of the upper water column in the Mediterranean Sea during more than 60 yea... more Abstract The evolution of the upper water column in the Mediterranean Sea during more than 60 years is reconstructed in terms of few parameters describing the mixed layer and the seasonal thermocline. The analysis covers the period 1945–2011 using data from three public sources: MEDAR-MEDATLAS, World Ocean Database, MFS-VOS program. Five procedures for estimating the mixed layer depth are described, discussed and compared using the 20-year long time series of temperature profiles of the DYFAMED station in the Ligurian Sea. On this basis the so-called three segments profile model (which approximates the upper water column with three segments representing mixed layer, thermocline and deep layer) has been selected for a systematic analysis at Mediterranean scale. A widespread increase of the thickness and temperature of the mixed layer, increase of the depth and decrease of the temperature of the thermocline base have been observed in summer and autumn during the recent decades. It is shown that positive temperature extremes of the mixed layer and of its thickness are potential drivers of the mass mortalities of benthic invertebrates documented since 1983. Hotspots of mixed layer anomalies have been also identified. These results refine previous analyses showing that ongoing and future warming of upper Mediterranean is likely to increase mass mortalities by producing environmental conditions beyond the limit of tolerance of some benthic species.
Physics And Chemistry Of The Earth, Parts A/b/c, 2012
An analysis of the climate change signal for seasonal temperature and precipitation over the Nort... more An analysis of the climate change signal for seasonal temperature and precipitation over the Northern Adriatic region is presented here. We collected 43 regional climate simulations covering the target area, including experiments produced in the context of the PRUDENCE and ENSEMBLES projects, and additional experiments produced by the Swedish Meteorological and Hydrological Institute. The ability of the models to simulate