A5037551559- Climate variability and models
- Meteorological Phenomena and Simulations
- Atmospheric and Environmental Gas Dynamics
- Arctic and Antarctic ice dynamics
- Atmospheric Ozone and Climate
- Oceanographic and Atmospheric Processes
- Hydrology and Drought Analysis
- Climate change and permafrost
- Forecasting Techniques and Applications
- Methane Hydrates and Related Phenomena
- Flood Risk Assessment and Management
- Science and Climate Studies
- Tropical and Extratropical Cyclones Research
- Plant Water Relations and Carbon Dynamics
- Scientific Computing and Data Management
- Fire effects on ecosystems
- Disaster Management and Resilience
- Atmospheric chemistry and aerosols
- demographic modeling and climate adaptation
- Medical and Agricultural Research Studies
- Geophysics and Gravity Measurements
- Educational Technology and Optimization
- Distributed and Parallel Computing Systems
- Hydrology and Watershed Management Studies
- Statistical and numerical algorithms
Federal Office of Meteorology and Climatology MeteoSwiss
2022
Universitat Politècnica de Catalunya
2016-2021
Barcelona Supercomputing Center
2016-2021
Institut Català de Ciències del Clima
2014-2017
ETH Zurich
2012-2015
Climate change is shaping extreme heat and rain. To what degree human activity has increased the risk of high impact events public concern still heavily debated. Recent studies attributed single to climate by comparing model experiments where influence an external driver can be included or artificially suppressed. Many these results however did not properly account for errors in simulating probabilities event occurrences. Here we show, exploiting advanced correction techniques from weather...
Abstract. The Earth System Model Evaluation Tool (ESMValTool) is a community diagnostics and performance metrics tool designed to improve comprehensive routine evaluation of system models (ESMs) participating in the Coupled Intercomparison Project (CMIP). It has undergone rapid development since first release 2016 now well-tested that provides end-to-end provenance tracking ensure reproducibility. consists (1) an easy-to-install, well-documented Python package providing core functionalities...
Abstract. The Stratosphere–troposphere Processes And their Role in Climate (SPARC) Quasi-Biennial Oscillation initiative (QBOi) aims to improve the fidelity of tropical stratospheric variability general circulation and Earth system models by conducting coordinated numerical experiments analysis. In equatorial stratosphere, QBO is most conspicuous mode variability. Five have therefore been designed (i) evaluate compare verisimilitude modelled QBOs under present-day conditions, (ii) identify...
Abstract Event attribution aims to estimate the role of an external driver after occurrence extreme weather and climate event by comparing probability that occurs in two counterfactual worlds. These probabilities are typically computed using ensembles simulations whose simulated known be imperfect. The implications imperfect models this context largely unknown, limited number observed events past conduct a robust evaluation. Using idealized framework, model limitation is studied generating...
Climate models are subject to high parametric uncertainty induced by poorly confined model parameters of parameterized physical processes. Uncertain typically calibrated in order increase the agreement with available observations. The common practice is adjust uncertain manually, often referred as expert tuning, which lacks objectivity and transparency use These shortcomings haze inter‐comparisons hinder implementation new parameterizations. Methods would allow systematically calibrate...
In general, biases of climate models depend upon the state (i.e., are nonstationary). Recent studies have shown that adoption a stationary temperature bias can lead to an overestimation projected summer warming in southern Europe. It has also been proposed use correction increases linearly with temperature. While such assumption is well‐justified for near‐term projections, one wonders whether and at what this relation levels off if it does. Here we show, using regional model simulations...
Abstract Resolution in climate models is thought to be an important factor for advancing seasonal prediction capability. To test this hypothesis, ensemble reforecasts are conducted over 1993–2009 with the European community model EC-Earth three configurations: standard resolution (~1° and ~60 km ocean atmosphere models, respectively), intermediate (~0.25° km), high ~39 two latter configurations being used without any specific tuning. The systematic biases of 2-m temperature, sea surface...
Abstract The Quasi‐biennial Oscillation (QBO) dominates the interannual variability of tropical stratosphere and influences other regions atmosphere. high predictability QBO implies that its teleconnections could lead to increased skill seasonal decadal forecasts provided relevant mechanisms are accurately represented in models. Here modelling sampling uncertainties examined using a multi‐model ensemble QBO‐resolving atmospheric general circulation models have carried out set coordinated...
Abstract Perturbed physics ensembles (PPEs) have been widely used to assess climate model uncertainties and provided new estimates of sensitivity parametric uncertainty in state-of-the-art models. So far, mainly global models were generate PPEs, little work has conducted with regional This paper discusses the parameter two PPEs a driven by reanalysis data for present over Europe. The is evaluated variables 2-m temperature, precipitation, total cloud cover, focus on annual cycle, interannual...
Abstract An important source of model uncertainty in climate models arises from unconfined parameters physical parameterizations. These are commonly estimated on the basis manual adjustments (expert tuning), which carries risk overtuning for a specific region or time period. This issue is particularly germane case regional (RCMs), often developed and used one few geographical regions only. study addresses role objective parameter calibration this context. Using previously methodology, an RCM...
Observational estimates of the climate system are essential to monitoring and understanding ongoing change assessing quality models used produce near- long-term information. This study poses dual unconventional question: Can be assess observational references? We show that this question not only rests on solid theoretical grounds but also offers insightful applications in practice. By comparing four products sea surface temperature with a large multimodel forecast ensemble, we find...
Abstract The skill of weather and climate forecast systems is often assessed by calculating the correlation coefficient between past forecasts their verifying observations. Improvements in can thus be quantified differences. uncertainty difference needs to judge whether observed constitutes a genuine improvement, or compatible with random sampling variations. A widely used statistical test for known unsuitable, because it assumes that competing forecasting are independent. In this paper,...
Abstract During the first quarter of 2015 United States experienced a widespread and extended episode low surface wind speeds. This had strong impact on power generation. Some farms did not generate enough cash for their steady payments, value some assets decreased. Although industry expressed concerns, has received much attention from scientific community remains weakly understood. In this paper we aim to fill gap advance understanding underlying processes at seasonal time scales. Using...
Abstract We present a robust assessment of the impact sea ice initialization from reconstructions real state on and atmosphere prediction skill. ran two ensemble seasonal experiments 1979 to 2012 : one using realistic initial conditions another where is initialized climatology, with forecast systems. During melting season in Arctic Ocean, forecasts become skilful until 3–5 months ahead, thanks memory held by thickness. freezing both Antarctic Oceans, are for 7 2 months, respectively,...
Abstract. The Earth System Model Evaluation Tool (ESMValTool), a community diagnostics and performance metrics tool for evaluation analysis of system models (ESMs), is designed to facilitate more comprehensive rapid comparison single or multiple participating in the Coupled Intercomparison Project (CMIP). ESM results can be compared against observations reanalysis data as well other including predecessor versions same model. updated extended version (v2.0) ESMValTool includes several new...
Attributing the change in likelihood of extreme weather events, particularly those occurring at small spatiotemporal scales, to anthropogenic forcing is a key challenge climate science. While warmer world associated with an increase atmospheric moisture on global scale, impact magnitude precipitation episodes has substantial regional variability. Analysis individual cases important understanding extent these changes spatial scales relevant stakeholders. Here, we present probabilistic...
Southern Africa and South America have experienced recent extremes in dry wet rainy seasons which caused severe socio-economic damages. Selected past extreme events are here studied, to estimate how human activity has changed the risk of occurrence such events, by applying an event attribution approach (Stott et al., 2004)comprising global climate models Coupled Model Intercomparison Project 5 (CMIP5). Our assessment shows that models' representation mean precipitation variability over is...
The last major volcanic eruptions, the Agung in 1963, El Chichon 1982 and Pinatubo 1991, were each associated with a cooling of troposphere that has been observed over large continental areas Western Pacific, Indian Ocean Southern Atlantic. Simultaneously, Eastern tropical Pacific temperatures increased due to prevailing Niño conditions. Here we show pattern these near-surface temperature anomalies is partly reproduced decadal simulations EC-Earth model initialised climate observations...
Northern Hemisphere western boundary currents, like the Gulf Stream, are key regions for cyclogenesis affecting large-scale atmospheric circulation. Recent observations and model simulations with high-temporal -spatial resolution have provided evidence that associated ocean fronts locally affect troposphere dynamics. A coherent view of how this affects mean climate its variability is, however, lacking. In particular separate role resolved atmosphere dynamics in shaping circulation is still...