The Impact of Climate Change upon the Snowmelt Hydrology of an Upland UK Catchment

Snowmelt hydrology is important in the winter flow regime of upland catchments in the UK as it can attenuate the extremes of the river flow hydrograph. The sensitivity of snow accumulation and melt to changes in climate, in particular to increases in temperature, could impact upon the variability of the winter flow regime. The potential impacts of this change are increases in flood risk and decreases in low flows. Hence this project investigated the consequences of projected climatic change upon snowmelt hydrology of the Dacre Beck catchment in the English Lake District. A distributed snowmelt model was created which spatialised temperature and precipitation data across the catchment. The model accumulated snow when the temperature fell below 0°C and applied one of three temperature-index snowmelt equations to melt the accumulated snowpack. The model was driven using stochastic baseline and projected (2050s medium emissions) weather series calculated using the UKCP09 weather generator. The results showed a large future reduction in both winter snow accumulation and the magnitude of snowmelt hydrology. However, the limited hydrological process representation of the model meant it could not reliably forecast changes in the winter flow regime. Therefore the snow accumulation and melt equations were incorporated into the physically based Connectivity Runoff Model (CRUM). This improved model was calibrated to observed discharge data within a Generalised Likelihood Uncertainty Estimation (GLUE) framework before being run with a sample of baseline and projected UKCP09 weather generator series. The results showed that both high and low flows in the winter flow regime were likely to increase which contradicted previous expectations but it was unclear about the role of snowmelt hydrology in these changes. Further investigation using temperature perturbed weather series found that these changes in the winter flow regime were most likely caused by increases in rainfall which overrode the impact of changes in snowmelt hydrology

Cartograms for use in forecasting weather driven natural hazards

This study evaluates the potential of using cartograms to visualise, and aid interpretation of, forecasts of weather driven natural hazards in the context of global weather forecasting and early warning systems. The use of cartograms is intended to supplement traditional cartographic representations of the hazards in order to highlight the severity of an upcoming event. Cartogrammetric transformations are applied to forecasts of floods, heatwaves, windstorms and snowstorms taken from the European Centre for Medium-range Weather Forecasts (ECMWF) forecast archive. Key cartogram design principles of importance in standard weather forecast visualisation are tested in terms of the tasks needed to visualise and interpret the forecast maps. These design principles include the influence of spatial autocorrelation of the variable mapped, the minimum and maximum values of a variable, the value of the sea, the addition of geographic features and the geographic extent used. Results show that the utility of the cartograms is dependent on these design principles, but the optimal cartogram transformation is dependent on geographical features (such as coastlines) and forecast features (such as snowstorm intensity). The importance of forecaster familiarisation training is highlighted. It was found in particular that for highly spatially autocorrelated weather variables used in analysing several upcoming natural hazards such as 2m temperature anomaly, the visualisation of the distortion provides a promising addition to standard forecast visualisations for highlighting upcoming weather driven natural hazards

The impact of SMOS soil moisture data assimilation within the Operational Global Flood Awareness System (GloFAS)

In this study the impacts of Soil Moisture and Ocean Salinity (SMOS) soil moisture data assimilation upon the streamflow prediction of the operational Global Flood Awareness System (GloFAS) were investigated. Two GloFAS experiments were performed, one which used hydro-meteorological forcings produced with the assimilation of the SMOS data, the other using forcings which excluded the assimilation of the SMOS data. Both sets of experiment results were verified against streamflow observations in the United States and Australia. Skill scores were computed for each experiment against the observation datasets, the differences in the skill scores were used to identify where GloFAS skill may be affected by the assimilation of SMOS soil moisture data. In addition, a global assessment was made of the impact upon the 5th and 95th GloFAS flow percentiles to see how SMOS data assimilation affected low and high flows respectively. Results against in-situ observations found that GloFAS skill score was only affected by a small amount. At a global scale, the results showed a large impact on high flows in areas such as the Hudson Bay, central United States, the Sahel and Australia. There was no clear spatial trend to these differences as opposing signs occurred within close proximity to each other. Investigating the differences between the simulations at individual gauging stations showed that they often only occurred during a single flood event; for the remainder of the simulation period the experiments were almost identical. This suggests that SMOS data assimilation may affect the generation of surface runoff during high flow events, but may have less impact on baseflow generation during the remainder of the hydrograph. To further understand this, future work could assess the impact of SMOS data assimilation upon specific hydrological components such as surface and subsurface runoff

Plastic in global rivers: are floods making it worse?

Riverine plastic pollution is of global concern due to its negative impact on ecosystem health and human livelihood. Recent studies show a strong link between river discharge and plastic transport, but the role of floods is still unresolved. We combined high-resolution mismanaged plastic waste data and river flood extents with increasing return periods to estimate flood-driven plastic mobilisation, from local to global scale. We show that 10 year return period floods already tenfold the global plastic mobilisation potential compared to non-flood conditions. In the worst affected regions, plastic mobilisation increases up to five orders of magnitude. Our results suggest a high inter-annual variability in plastic mobilisation, previously ignored by global plastic transport models. Flood defences reduce plastic mobilisation substantially, but regions vulnerable to flooding often coincide with high plastic mobilisation potential during floods. Consequentially, clean-up and mitigation measures and flood risk management are inherently interdependent and need to be managed holistically

Can global rainfall forecasts identify areas at flash flood risk? Proof of concept for Ecuador

Globally, flash floods are one of the costliest natural hazards for property damage and loss of life. The low accuracy of flash flood forecasts beyond a few hours limits their use in early warning systems. This study aims to compare the performance of ECMWF raw ensemble (ENS) and ecPoint rainfall forecasts. These two systems are profoundly different because the first provides forecasts at a grid-scale while the second provides forecasts at a point-scale that mirror point observations such as rain gauges. ecPoint rainfall forecasts have been shown to provide better guidance than ENS in predicting extreme (localized) rainfall up to 10 days ahead. Hence, this study assesses whether ecPoint also enhances ENS performance in identifying areas at risk of flash floods up to medium-range leads. A one-year objective verification was conducted for flash flood events in Ecuador. The country’s varied climate and the existence of a comprehensive database describing the occurrence of flash flood events made Ecuador an attractive site for the verification analysis. Knowing the magnitudes of flash-flood-triggering rainfall events is imperative to carry out the objective verification analysis. The authors did not have this information at their disposal, and suitable rainfall observations were not available to estimate the magnitudes of flash-flood-triggering rainfall events. This study proposes a methodology that uses short-term ecPoint rainfall forecasts as a proxy for point rainfall observations to define the magnitude of flash-flood triggering rainfall events when suitable rainfall observations are unavailable. Due to the probabilistic nature of the ecPoint output, this approach simulates a very high-density observational network in data-scarce regions. From a general comparison of the rainfall thresholds defined using short-range ecPoint rainfall forecast and those computed from a low-density observational network, overall, the flash-flood-triggering rainfall thresholds seem reasonable, but they might be slightly underestimated in the coastal region and overestimated in the Andean region. The verification results suggest that ecPoint generally provides better guidance than ENS in identifying areas at risk of flash floods when rainfall originates from small-scale convective systems. In these cases, ENS might completely miss the flash flood event, while ecPoint was able to anticipate it. When rainfall originates from large-scale convective systems, ecPoint and ENS performances are comparable, showing that ENS can predict areas at risk of flash floods around the globe up to medium-range leads under certain weather conditions. However, ecPoint provides better guidance on the magnitude of the flash-flood-triggering rainfall events. The findings of this study have the potential to significantly improve early warning systems, aid decision-makers, and enhance emergency preparedness worldwide against flash floods. This would ultimately contribute to better mitigation of the devastating impacts of flash floods on communities and infrastructure

The Global Flood Partnership Conference 2017 - From hazards to impacts

From 27 – 29 June 2017, the 2017 Global Flood Partnership Conference was held at the University of Alabama, U.S.A. More than 90 participants attended the conference coming from 11 different countries in 5 continents. They represented 56 institutions including international organisations, the private sector, national authorities, universities, governmental research agencies and non-profit organisations. Each year, floods cause devastating losses and damage across the world. Growing populations in ill-planned flood-prone coastal and riverine areas are increasingly exposed to more extreme rainfall events. With more population and economic assets at risk, governments, banks, international development and relief agencies, and private firms are investing in flood reduction measures. However, in many countries, the flood risk is not managed optimally because of a lack of scientific data and methods or a communication gap between science and risk managers. The Global Flood Partnership was launched in 2014 and is a cooperation framework between scientific organisations and flood disaster managers worldwide to develop flood observational and modeling infrastructure, leveraging on existing initiatives for better predicting and managing flood disaster impacts and flood risk globally. The conference theme was “From hazards to impacts” and participants had the opportunity to showcase their latest relevant research and activities. As usual, the advances and success stories of the Partnership were reviewed and the next steps to further strengthen the GFP were discussed. As in past meetings, participants had numerous opportunities to present their work, exchange ideas, and turn it into a lively and successful meeting. This included a "Marketplace of Ideas" session, "Ignite" talks, Problem-solving session, workshops, poster pitch session and breakout groups.JRC.E.1-Disaster Risk Managemen

EFAS upgrade for the extended model domain

This publication is a Technical report by the Joint Research Centre (JRC), the European Commission’s science and knowledge service. It aims to provide evidence-based scientific support to the European policymaking process. The scientific output expressed does not imply a policy position of the European Commission. Neither the European Commission nor any person acting on behalf of the Commission is responsible for the use that might be made of this publication.JRC.E.1-Disaster Risk Managemen

EFAS upgrade for the extended model domain

This publication is a Technical report by the Joint Research Centre (JRC), the European Commission’s science and knowledge service. It aims to provide evidence-based scientific support to the European policymaking process. The scientific output expressed does not imply a policy position of the European Commission. Neither the European Commission nor any person acting on behalf of the Commission is responsible for the use that might be made of this publication.JRC.E.1-Disaster Risk Managemen

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection