Drift simulation of MH370 debris using superensemble techniques

Abstract. On 7 March 2014 (UTC), Malaysia Airlines flight 370 vanished without a trace. The aircraft is believed to have crashed in the southern Indian Ocean, but despite extensive search operations the location of the wreckage is still unknown. The first tangible evidence of the accident was discovered almost 17 months after the disappearance. On 29 July 2015, a small piece of the right wing of the aircraft was found washed up on the island of Réunion, approximately 4000 km from the assumed crash site. Since then a number of other parts have been found in Mozambique, South Africa and on Rodrigues Island. This paper presents a numerical simulation using high-resolution oceanographic and meteorological data to predict the movement of floating debris from the accident. Multiple model realisations are used with different starting locations and wind drag parameters. The model realisations are combined into a superensemble, adjusting the model weights to best represent the discovered debris. The superensemble is then used to predict the distribution of marine debris at various moments in time. This approach can be easily generalised to other drift simulations where observations are available to constrain unknown input parameters. The distribution at the time of the accident shows that the discovered debris most likely originated from the wide search area between 28 and 35° S. This partially overlaps with the current underwater search area, but extends further towards the north. Results at later times show that the most probable locations to discover washed-up debris are along the African east coast, especially in the area around Madagascar. The debris remaining at sea in 2016 is spread out over a wide area and its distribution changes only slowly

VISIR-I: Small vessels - Least-time nautical routes using wave forecasts

A new numerical model for the on-demand computation of optimal ship routes based on sea-state forecasts has been developed. The model, named VISIR (discoVerIng Safe and effIcient Routes) is designed to support decision-makers when planning a marine voyage. The first version of the system, VISIR-I, considers medium and small motor vessels with lengths of up to a few tens of metres and a displacement hull. The model is comprised of three components: a route optimization algorithm, a mechanical model of the ship, and a processor of the environmental fields. The optimization algorithm is based on a graph-search method with time-dependent edge weights. The algorithm is also able to compute a voluntary ship speed reduction. The ship model accounts for calm water and added wave resistance by making use of just the principal particulars of the vessel as input parameters. It also checks the optimal route for parametric roll, pure loss of stability, and surfriding/broaching-to hazard conditions. The processor of the environmental fields employs significant wave height, wave spectrum peak period, and wave direction forecast fields as input. The topological issues of coastal navigation (islands, peninsulas, narrow passages) are addressed. Examples of VISIR-I routes in the Mediterranean Sea are provided. The optimal route may be longer in terms of miles sailed and yet it is faster and safer than the geodetic route between the same departure and arrival locations. Time savings up to 2.7% and route lengthening up to 3.2% are found for the case studies analysed. However, there is no upper bound for the magnitude of the changes of such route metrics, which especially in case of extreme sea states can be much greater. Route diversions result from the safety constraints and the fact that the algorithm takes into account the full temporal evolution and spatial variability of the environmental fields

Coastal ocean forecasting with an unstructured grid model in the southern Adriatic and northern Ionian seas

Abstract. SANIFS (Southern Adriatic Northern Ionian coastal Forecasting System) is a coastal-ocean operational system based on the unstructured grid finite-element three-dimensional hydrodynamic SHYFEM model, providing short-term forecasts. The operational chain is based on a downscaling approach starting from the large-scale system for the entire Mediterranean Basin (MFS, Mediterranean Forecasting System), which provides initial and boundary condition fields to the nested system. The model is configured to provide hydrodynamics and active tracer forecasts both in open ocean and coastal waters of southeastern Italy using a variable horizontal resolution from the open sea (3–4 km) to coastal areas (50–500 m). Given that the coastal fields are driven by a combination of both local (also known as coastal) and deep-ocean forcings propagating along the shelf, the performance of SANIFS was verified both in forecast and simulation mode, first (i) on the large and shelf-coastal scales by comparing with a large-scale survey CTD (conductivity–temperature–depth) in the Gulf of Taranto and then (ii) on the coastal-harbour scale (Mar Grande of Taranto) by comparison with CTD, ADCP (acoustic doppler current profiler) and tide gauge data. Sensitivity tests were performed on initialization conditions (mainly focused on spin-up procedures) and on surface boundary conditions by assessing the reliability of two alternative datasets at different horizontal resolution (12.5 and 6.5 km). The SANIFS forecasts at a lead time of 1 day were compared with the MFS forecasts, highlighting that SANIFS is able to retain the large-scale dynamics of MFS. The large-scale dynamics of MFS are correctly propagated to the shelf-coastal scale, improving the forecast accuracy (+17 % for temperature and +6 % for salinity compared to MFS). Moreover, the added value of SANIFS was assessed on the coastal-harbour scale, which is not covered by the coarse resolution of MFS, where the fields forecasted by SANIFS reproduced the observations well (temperature RMSE equal to 0.11 °C). Furthermore, SANIFS simulations were compared with hourly time series of temperature, sea level and velocity measured on the coastal-harbour scale, showing a good agreement. Simulations in the Gulf of Taranto described a circulation mainly characterized by an anticyclonic gyre with the presence of cyclonic vortexes in shelf-coastal areas. A surface water inflow from the open sea to Mar Grande characterizes the coastal-harbour scale

A meteo-hydrological modelling system for the reconstruction of river runoff: the case of the Ofanto river catchment

A meteo-hydrological modelling system has been designed for the reconstruction of long time series of rainfall and river runoff events. The modelling chain consists of the mesoscale meteorological model of the Weather Research and Forecasting (WRF), the land surface model NOAH-MP and the hydrology-hydraulics model WRF-Hydro. Two 3-month periods are reconstructed for winter 2011 and autumn 2013, containing heavy rainfall and river flooding events. Several sensitivity tests were performed along with an assessment of which tunable parameters, numerical choices and forcing data most impacted on the modelling performance. The calibration of the experiments highlighted that the infiltration and aquifer coefficients should be considered as seasonally dependent. The WRF precipitation was validated by a comparison with rain gauges in the Ofanto basin. The WRF model was demonstrated to be sensitive to the initialization time and a spin-up of about 1.5 days was needed before the start of the major rainfall events in order to improve the accuracy of the reconstruction. However, this was not sufficient and an optimal interpolation method was developed to correct the precipitation simulation. It is based on an objective analysis (OA) and a least square (LS) melding scheme, collectively named OA+LS. We demonstrated that the OA+LS method is a powerful tool to reduce the precipitation uncertainties and produce a lower error precipitation reconstruction that itself generates a better river discharge time series. The validation of the river streamflow showed promising statistical indices. The final set-up of our meteo-hydrological modelling system was able to realistically reconstruct the local rainfall and the Ofanto hydrograph

Collaboration experience between Dermatology Unit and Infectious Disease Clinic in Modena: optimization strategies for HIV, hepatitis and syphilis screening tests

Introduction Screening tests for HIV, HBV, HCV and syphilis are very important to detect and treat these infections at an early stage and prevent their diffusion inside communities. Sexually Transmitted Diseases Ambulatory of Dermatology Unit (STDs-DU) and “Test & Counselling” Ambulatory of Infectious Disease Clinic (T&C-IDC) in Modena began collaboration in 2010 and adopted a common diagnostic serological profile since 2013. Objective The main aim of the study was to analyse the results of screening tests performed in the STDs-DU and T&C-IDC, comparing the results obtained after the adoption of the shared protocol with the previous period. The secondary objective was to evaluate the efficacy of our collaboration in term of number of new diagnoses and linkage to care. Materials and Methods Consecutive patients referred to the STDs-DU and T&C-IDC from January 2010 to December 2016, with at least one performed screening test for HIV, HBV, HCV and syphilis were enrolled. Referral of patients with a new infection was obtained by capture-recapture methods in hospital databases. Results During the seven-years observation we collected 13117 admittances for 9154 patients. We observed a significant increase in the number of screening tests (p<0.001) and ratio between tests and admissions (p=0.002). 644 (7.0%) people with at least one infection were diagnosed. Among these, the most common was syphilis (41.9%), followed by HBV (25.7%), HCV (21.4%) and HIV (10.9%). Syphilis and HCV occurred predominantly in Italians (72.5% and 81.1%) and males (75.7% and 75.5%), while foreign-born (85.5%) mainly harboured HBV infection. HIV diagnosis was detected more frequently among males (67.1%) with a similar proportion between Italians and foreign-born. 543 out of 644 (84.3%) patients were linked to care. Conclusions The cooperation between STDs-DU and T&C-IDC has proven to work well increasing the diagnosis over the time and obtaining good results in linkage to care

Optimization strategies for HIV, syphilis and hepatitis testings in infectious disease and dermatology clinics: preliminary results of Modena collaboration experience

Background: HIV and sexually transmitted diseases (STDs) screening tests are usually offered in many Italian health institutions. These tests are very important for detection of HIV and STDs, for treating them at an early stage and for prevention of diffusion inside communities. Generally, HIV test is the only screening exam performed in Infectious Disease Clinic (IDC). Increased collaboration between IDC and STDs Centre using the same approach to test sexually transmitted infections could implement the number of new diagnoses. In the Azienda Ospedaliero-Universitaria (AOU) of Modena, the IDC and STDs Centre of Dermatology Clinic began a strict collaboration and adopted a common diagnostic profile including HIV, syphilis, HBV and HCV screening tests since 2013. The aim of the study was to observe the results of a seven-years collaboration in term of number of new HIV and STDs diagnoses. Material & Methods: Consecutive patients who underwent at least 1 screening test for HIV, syphilis, HBV and HCV from January 2010 to September 2016 in IDC or STDs Centre were included. Demographical data were electronically recorded in clinical databases. “Linkage to care” was obtained through a capture and recapture method using Modena HIV surveillance System and Modena HIV clinic databases. Results: During the study period 10675 admittances related to 8623 patients, who carried out at least 1 screening test, were registered in the centres. They were mainly male (68.2%). Median age was 33 years-old (IQR 26-43). Foreigners represented 26.5% of tested people. Since 2013 an increasing number of admittances was observed (1343 accesses in 2010 and 1901 in 2015). HBV, HCV and syphilis tests increased in IDC after 2013 as well as HIV tests in STDs Centre (Figure 1). A total of 700 people were positive for at least 1 screening test: 71 with HIV infection (2016 incidence rate 1.4%), 314 with syphilis (2016 incidence rate 1.3%), 182 with HCV infection (2016 incidence rate 1.64%) and 161 with HBV infection (2016 incidence rate 3.8%). The number of HIV and HBV positive tests increased in the last 2 years but the trend was statistically significant only for HIV (p<0.001). 57% of HIV new infections were observed in Italian men, while 82% of new HBV infections were detected in young foreigners. During the study period the number of new syphilis infections showed a reduction (p<0.001) while HCV positive tests were changeless (p=0.245). 87.6% of new infections were found be linked in care in AOU of Modena. Conclusion: The agreement between IDC and STDs Centre has proven to work well increasing the diagnosis over the time and obtaining a good results in “linkage to care”, which allows to patients with positive screening test to be sent to the pertinent Clinic for further investigations and therapeutical management

A meteo-hydrological modelling system for the reconstruction of river runoff: the case of the Ofanto river catchment

Abstract. A meteo-hydrological modelling system has been designed for the reconstruction of long time series of rainfall and river runoff events. The modelling chain consists of the mesoscale meteorological model of the Weather Research and Forecasting (WRF), the land surface model NOAH-MP and the hydrology–hydraulics model WRF-Hydro. Two 3-month periods are reconstructed for winter 2011 and autumn 2013, containing heavy rainfall and river flooding events. Several sensitivity tests were performed along with an assessment of which tunable parameters, numerical choices and forcing data most impacted on the modelling performance.The calibration of the experiments highlighted that the infiltration and aquifer coefficients should be considered as seasonally dependent.The WRF precipitation was validated by a comparison with rain gauges in the Ofanto basin. The WRF model was demonstrated to be sensitive to the initialization time and a spin-up of about 1.5 days was needed before the start of the major rainfall events in order to improve the accuracy of the reconstruction. However, this was not sufficient and an optimal interpolation method was developed to correct the precipitation simulation. It is based on an objective analysis (OA) and a least square (LS) melding scheme, collectively named OA+LS. We demonstrated that the OA+LS method is a powerful tool to reduce the precipitation uncertainties and produce a lower error precipitation reconstruction that itself generates a better river discharge time series. The validation of the river streamflow showed promising statistical indices.The final set-up of our meteo-hydrological modelling system was able to realistically reconstruct the local rainfall and the Ofanto hydrograph

Optimization strategies for HIV, hepatitis and syphilis testing in Infectious Disease Clinic and Dermatology Unit of Modena: seven-years results of collaboration experience

Introduction: Human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV) and syphilis infections modify the epidemiology and presentation of each other. Screening tests are very important for detection of sexually transmitted infections (STIs), for treating them at an early stage and prevent the diffusion inside communities. “Test & Counselling” Ambulatory of Infectious Disease Clinic (T&C-IDC) and Sexually Transmitted Diseases Ambulatory of Dermatology Unit (STDs-DU) of the Azienda Ospedaliero-Universitaria Policlinico of Modena began collaboration in 2010 and adopted a common diagnostic profile since 2013. The main objective was to analyse the results of screening tests performed in the T&C-IDC and STDs-DU during the study period in order to identify early HIV, HBV, HCV and syphilis infections. The secondary objective was to evaluate the efficacy of our collaboration in term of number of new STIs diagnoses and linkage to care. Material and Methods: Consecutive patients referred to the T&C-IDC and STDs-DU from January 2010 to December 2016, with at least one performed screening test for HIV, HBV, HCV and syphilis were enrolled. Demographic and laboratory data were acquired from each patient. Linkage to care of positive patients was obtained through a join of different outpatient clinical databases. Results: During the seven-years observation we collected 13117 admittances for 9154 patients. Median age was 35.1 years ± 12.6 and foreign-born population represents 29% of the tested people. People who resulted positive for at least one screening test increased during the study period. A total of 668 infections were detected in 644 patients. Discussion: The agreement between T&C-IDC and STDs-DU has proven to work well increasing the diagnosis over the time and obtaining a good results in linkage to care, which allows to patients with positive screening test to be sent to the pertinent Clinic for further investigations and therapeutic management

Strategic environmental sensitivity mapping for oil spill contingency planning in the Peruvian marine-coastal zone

Major oil spills can cause significant impacts on marine-coastal zones, particularly on areas with a high oil spill risk, which combine a high oil spill hazard-high likelihood of oil stranding at high concentrations, and a high environmental sensitivity-high concentration of highly sensitive ecological and socioeconomic resources. In this context, a straightforward multicriteria methodology is proposed to determine the second factor of the oil spill risk, namely the strategic environmental sensitivity (SES), in 68 sectors covering the entire Peruvian marine-coastal zone. The methodology comprised the weighted integration of physical, biological, and socioeconomic sensitivity indicators based on their relevance in surface marine oil spills and the Peruvian ecological and socioeconomic context. As a result, relative SES levels from very low to very high were assigned to the sectors. To demonstrate the SES applicability, an oil spill risk assessment at a screening level was performed in a selected sector with current oil production activities. The oil beaching likelihood of worst-case discharge scenarios modelled for January 2021 was used to determine an overall screening oil spill hazard level in the selected sector, while a matrix relating the SES and hazard determined the screening oil spill risk. The results can be used as a decision-support tool to enhance the oil spill contingency planning in Peru or be used in other relevant processes such as the integrated coastal zone management, the marine spatial planning, or the contingency planning of other liquid contaminants. In addition, the proposed methodologies can be adapted to different local and international contexts and scales

A relocatable ocean modelling platform for downscaling to shelf-coastal areas to support disaster risk reduction

High-impact ocean weather events and climate extremes can have devastating effects on coastal zones and small islands. Marine Disaster Risk Reduction (DRR) is a systematic approach to such events, through which the risk of disaster can be identified, assessed and reduced. This can be done by improving ocean and atmosphere prediction models, data assimilation for better initial conditions and developing an efficient and sustainable impact forecasting methodology for Early Warnings Systems. A common user request during disaster remediation actions is for high-resolution information, which can be derived from easily deployable numerical models nested into operational larger-scale ocean models. The Structured and Unstructured Relocatable Ocean Model for Forecasting (SURF) enables users to rapidly deploy a nested high-resolution numerical model into larger-scale ocean forecasts. Rapidly downscaling the currents, sea level, temperature, and salinity fields is critical in supporting emergency responses to extreme events and natural hazards in the world’s oceans. The most important requirement in a relocatable model is to ensure that the interpolation of low-resolution ocean model fields (analyses and reanalyses) and atmospheric forcing is tested for different model domains. The provision of continuous ocean circulation forecasts through the Copernicus Marine Environment Monitoring Service (CMEMS) enables this testing. High-resolution SURF ocean circulation forecasts can be provided to specific application models such as oil spill fate and transport models, search and rescue trajectory models, and ship routing models requiring knowledge of meteooceanographic conditions. SURF was used to downscale CMEMS circulation analyses in four world ocean regions, and the high-resolution currents it can simulate for specific applications are examined. The SURF downscaled circulation fields show that the marine current resolutions affect the quality of the application models to be used for assessing disaster risks, particularly near coastal areas where the coastline geometry must be resolved through a numerical grid, and high-frequency coastal currents must be accurately simulated