Deconvolution in Auger Electron Spectroscopy

Deconvolution calculations have been applied in Auger Electron Spectroscopy to increase resolution and/or to eliminate loss features. We present: i) A short review of the methodology; ii) Recent results obtained in our laboratory in spectroscopy of Al, Ni, Cu, Ag and Te; iii) A discussion on the conditions for the appearance of artefacts originating either in the calculation or the physical processes (emission anisotropy, distribution of electron path lengths, and intrinsic losses)

Propagation from meteorological to hydrological drought in the Horn of Africa using both standardized and threshold-based indices

There have been numerous drought propagation studies in data-rich countries, but not much has been done for data-poor regions (such as the Horn of Africa, HOA). In this study, we characterize meteorological, soil moisture and hydrological drought and the propagation from one to the other for 318 catchments in the HOA to improve understanding of the spatial variability in the drought hazard. We calculate the standardized precipitation index (SPI), standardized soil moisture index (SSMI) and standardized streamflow index (SSI). In addition, we use the variable threshold method to calculate the duration of drought below a predefined percentile threshold for precipitation, soil moisture and discharge. The relationship between meteorological and soil moisture drought is investigated by finding the SPI accumulation period that has the highest correlation between SPI and SSMI, and the relationship between meteorological and hydrological drought is analysed by the SPI accumulation period that has the highest correlation between SPI and SSI time series. Additionally, we calculated these relationships with the ratio between the threshold-based meteorological-drought duration and soil moisture drought duration and the relation between threshold-based meteorological-drought duration and streamflow drought duration. Finally, we investigate the influence of climate and catchment characteristics on these propagation metrics. The results show that (1) the propagation from SPI to SSMI and the mean drought duration ratio of meteorological to soil moisture drought (P / SM) are mainly influenced by soil properties and vegetation, with the short accumulation periods (1 to 4 months) of SPI in catchments with arable land, high mean annual precipitation, and low sand and silt content, while longer accumulations (5 to 7 months) are in catchments with low mean annual upstream precipitation and shrub vegetation; (2) the propagation from SPI to SSI and precipitation-to-streamflow duration ratio are highly influenced by the climate and catchment control, i.e. geology, elevation and land cover, with the short accumulation times in catchments with high annual precipitation, volcanic permeable geology and cropland and the longer accumulations in catchments with low annual precipitation, sedimentary rocks and shrubland; and (3) the influence of mean annual upstream precipitation is more important for the propagation from SPI to SSI than from SPI to SSMI. Additionally, precipitation accumulation periods of approximately 1 to 4 months in wet western areas of the HOA and of approximately 5 to 7 months in the dryland regions are found. This can guide forecasting and management efforts as different drought metrics are thus of importance in different regions.</p

The Asynergies of Structural Disaster Risk Reduction Measures: Comparing Floods and Earthquakes

Traditionally, building‐level disaster risk reduction (DRR) measures are aimed at a single natural hazard. However, in many countries the society faces the threat of multiple hazards. Building‐level DRR measures that aim to decrease earthquake vulnerability can have opposing or conflicting effects on flood vulnerability, and vice versa. In a case study of Afghanistan, we calculate the risk of floods and earthquakes, in terms of average annual losses (AAL), in the current situation. Next, we develop two DRR scenarios, where building‐level measures to reduce flood and earthquake risk are implemented. We use this to identify districts for which DRR measures of one hazard increase the risk of another hazard. We then also calculate the optimal situation between the two scenarios by, for each district, selecting the DRR scenario for which the AAL as a ratio of the total exposure is lowest. Finally, we assess the sensitivity of the total risk to each scenario. The optimal measure differs spatially throughout Afghanistan, but in most districts it is more beneficial to take flood DRR measures. However, in the districts where it is more beneficial to take earthquake measures, the reduction in risk is considerable (up to 40%, while flood DRR measures lead to a reduction in risk by 16% in individual districts). The introduction of asynergies between DRR measures in risk analyses allows policy‐makers to spatially differentiate building codes and other building‐level DRR measures to address the most prevalent risk while not compromising the risk resulting from other hazards

Using rapid damage observations for Bayesian updating of hurricane vulnerability functions: A case study of Hurricane Dorian using social media

Rapid impact assessments immediately after disasters are crucial to enable rapid and effective mobilization of resources for response and recovery efforts. These assessments are often performed by analysing the three components of risk: hazard, exposure and vulnerability. Vulnerability curves are often constructed using historic insurance data or expert judgments, reducing their applicability for the characteristics of the specific hazard and building stock. Therefore, this paper outlines an approach to the creation of event-specific vulnerability curves, using Bayesian statistics (i.e., the zero-one inflated beta distribution) to update a pre-existing vulnerability curve (i.e., the prior) with observed impact data derived from social media. The approach is applied in a case study of Hurricane Dorian, which hit the Bahamas in September 2019. We analysed footage shot predominantly from unmanned aerial vehicles (UAVs) and other airborne vehicles posted on YouTube in the first 10 days after the disaster. Due to its Bayesian nature, the approach can be used regardless of the amount of data available as it balances the contribution of the prior and the observations

Regionale kennisarrangementen: verslag van quickscan en kennisdag 2009

In veel regio’s zijn burgers, bestuurders en ondernemers actief betrokken bij de ontwikkeling van hun omgeving. In het kader van gebiedsplannen wordt gewerkt aan doelen op het terrein van landschap, natuur, landbouw en plattelandsontwikkeling. Hierbij komen uiteenlopende (kennis)vragen naar boven. De kennisvragen worden vaak ad hoc gesteld en men weet vaak niet waar men terecht kan. In een aantal regio’s in Nederland wordt dit verschijnsel onderkend en groeit het besef dat het zoeken naar de antwoorden op deze kennisvragen een serieuze bijdrage levert aan gebiedsontwikkeling. Hier wordt een verbinding met onderwijs en onderzoek gemaakt. Omdat ook bij de kennisinstellingen steeds vaker wordt gezocht naar manieren om meer praktijkgerichte werken, ontstaan er samenwerkingsverbanden. Deze verbindingen tussen regio en onderwijs en onderzoek rond kennisvragen, noemen we een regionaal kennisarrangemen

Future changes in Mekong River hydrology: impact of climate change and reservoir operation on discharge

The transboundary Mekong River is facing two ongoing changes that are expected to significantly impact its hydrology and the characteristics of its exceptional flood pulse. The rapid economic development of the riparian countries has led to massive plans for hydropower construction, and projected climate change is expected to alter the monsoon patterns and increase temperature in the basin. The aim of this study is to assess the cumulative impact of these factors on the hydrology of the Mekong within next 20–30 yr. We downscaled the output of five general circulation models (GCMs) that were found to perform well in the Mekong region. For the simulation of reservoir operation, we used an optimisation approach to estimate the operation of multiple reservoirs, including both existing and planned hydropower reservoirs. For the hydrological assessment, we used a distributed hydrological model, VMod, with a grid resolution of 5 km &amp;times; 5 km. In terms of climate change's impact on hydrology, we found a high variation in the discharge results depending on which of the GCMs is used as input. The simulated change in discharge at Kratie (Cambodia) between the baseline (1982–1992) and projected time period (2032–2042) ranges from &amp;minus;11% to &amp;plus;15% for the wet season and &amp;minus;10% to &amp;plus;13% for the dry season. Our analysis also shows that the changes in discharge due to planned reservoir operations are clearly larger than those simulated due to climate change: 25–160% higher dry season flows and 5–24% lower flood peaks in Kratie. The projected cumulative impacts follow rather closely the reservoir operation impacts, with an envelope around them induced by the different GCMs. Our results thus indicate that within the coming 20–30 yr, the operation of planned hydropower reservoirs is likely to have a larger impact on the Mekong hydrograph than the impacts of climate change, particularly during the dry season. On the other hand, climate change will increase the uncertainty of the estimated reservoir operation impacts: our results indicate that even the direction of the flow-related changes induced by climate change is partly unclear. Consequently, both dam planners and dam operators should pay closer attention to the cumulative impacts of climate change and reservoir operation on aquatic ecosystems, including the multibillion-dollar Mekong fisheries

Improving flood damage assessment models in Italy

Flood damage assessments are often based on stage-damage curve (SDC) models that estimate economic damage as a function of flood characteristics (typically flood depths) and land use. SDCs are developed through a site-specific analysis, but are rarely adjusted to economic circumstances in areas to which they are applied. In Italy, assessments confide in SDC models developed elsewhere, even if empirical damage reports are collected after every major flood event. In this paper, we have tested, adapted and extended an up-to-date SDC model using flood records from Northern Italy. The model calibration is underpinned by empirical data from compensation records. Our analysis takes into account both damage to physical assets and losses due to foregone production, the latter being measured amidst the spatially distributed gross added value