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- Fu, G. (author), Lin, H.X. (author), Heemink, A.W. (author), Segers, A. (author), Lu, S. (author), Palsson, T. (author) conference paper 2015
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- Lu, S. (author), Lin, H.X. (author), Heemink, A.W. (author), Segers, A. (author), Fu, G. (author) conference paper 2015
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- Heemink, A.W. (author), Segers, A.J. (author) journal article 2002
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Fu, G. (author), Lin, H.X. (author), Heemink, A.W. (author), Segers, A.J. (author), Lu, S. (author), Palsson, T. (author)The 2010 Eyjafjallajokull volcano eruption had serious consequences to civil aviation. This has initiated a lot of research on volcanic ash transport forecast in recent years. For forecasting the volcanic ash transport after eruption onset, a volcanic ash transport and diffusion model (VATDM) needs to be run with Eruption Source Parameters (ESP)...journal article 2015
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Lu, S. (author), Lin, X. (author), Heemink, A.W. (author), Fu, G. (author), Segers, A.J. (author)Volcanic ash forecasting is a crucial tool in hazard assessment and operational volcano monitoring. Emission parameters such as plume height, total emission mass, and vertical distribution of the emission plume rate are essential and important in the implementation of volcanic ash models. Therefore, estimation of emission parameters using...journal article 2015
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Yarce Botero, A. (author), Lopez Restrepo, S. (author), Pinel Pelaez, N. (author), Quintero-Montoya, Olga (author), Segers, Arjo (author), Heemink, A.W. (author)In this work, we present the development of a 4D-Ensemble-Variational (4DEnVar) data assimilation technique to estimate NOx top-down emissions using the regional chemical transport model LOTOS-EUROS with the NO2 observations from the TROPOspheric Monitoring Instrument (TROPOMI). The assimilation was performed for a domain in the northwest of...journal article 2021
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Lopez Restrepo, S. (author), Nino-Ruiz, Elias D. (author), Guzman-Reyes, Luis G. (author), Yarce, Andres (author), Quintero, O. L. (author), Pinel, Nicolas (author), Segers, Arjo (author), Heemink, A.W. (author)In this paper, we propose an efficient and practical implementation of the ensemble Kalman filter via shrinkage covariance matrix estimation. Our filter implementation combines information brought by an ensemble of model realizations, and that based on our prior knowledge about the dynamical system of interest. We perform the combination of...journal article 2021
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Hinestroza-Ramirez, Jhon E. (author), Lopez-Restrepo, Santiago (author), Yarce Botero, A. (author), Segers, Arjo (author), Rendon-Perez, Angela Maria (author), Isaza-Cadavid, Santiago (author), Heemink, A.W. (author), Quintero, Olga Lucia (author)Chemical transport models (CTM) are crucial for simulating the distribution of air pollutants, such as particulate matter, and evaluating their impact on the environment and human health. However, these models rely heavily on accurate emission inventory and meteorological inputs, usually obtained from reanalyzed weather data, such as the...journal article 2023
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Fu, Guangliang (author), Prata, Fred (author), Lin, H.X. (author), Heemink, A.W. (author), Segers, AJ (author), Lu, S. (author)Using data assimilation (DA) to improve model forecast accuracy is a powerful approach that requires available observations. Infrared satellite measurements of volcanic ash mass loadings are often used as input observations for the assimilation scheme. However, because these primary satellite-retrieved data are often two-dimensional (2-D) and...journal article 2017
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Jin, J. (author), Segers, Arjo (author), Liao, Hong (author), Heemink, A.W. (author), Kranenburg, Richard (author), Lin, H.X. (author)Emission inversion using data assimilation fundamentally relies on having the correct assumptions about the emission background error covariance. A perfect covariance accounts for the uncertainty based on prior knowledge and is able to explain differences between model simulations and observations. In practice, emission uncertainties are...journal article 2020
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Lopez Restrepo, S. (author), Yarce Botero, A. (author), Pinel Pelaez, N. (author), Quintero Montoya, O.L. (author), Segers, Arjo (author), Heemink, A.W. (author)The use of low air quality networks has been increasing in recent years to study urban pollution dynamics. Here we show the evaluation of the operational Aburrá Valley’s low-cost network against the official monitoring network. The results show that the PM<sub>2.5</sub> low-cost measurements are very close to those observed by the official...journal article 2021
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Jin, J. (author), Segers, Arjo (author), Lin, H.X. (author), Henzing, Bas (author), Wang, X. (author), Heemink, A.W. (author), Liao, Hong (author)When calibrating simulations of dust clouds, both the intensity and the position are important. Intensity errors arise mainly from uncertain emission and sedimentation strengths, while position errors are attributed either to imperfect emission timing or to uncertainties in the transport. Though many studies have been conducted on the...journal article 2021
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Lopez Restrepo, S. (author), Yarce Botero, A. (author), Pinel, Nicolás (author), Quintero, O. L. (author), Segers, Arjo (author), Heemink, A.W. (author)This work proposes a robust and non-Gaussian version of the shrinkage-based knowledge-aided EnKF implementation called Ensemble Time Local H<sub>∞</sub> Filter Knowledge-Aided (EnTLHF-KA). The EnTLHF-KA requires a target covariance matrix to integrate previously obtained information and knowledge directly into the data assimilation (DA). The...journal article 2022
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Lu, S. (author), Lin, H.X. (author), Heemink, A.W. (author), Segers, Arjo (author), Fu, Guangliang (author)In this paper, we reconstruct the vertical profile of volcanic ash emissions by assimilating satellite data and ground-based observations using a modified trajectory-based 4D-Var (Trj4DVar) approach. In our previous work, we found that the lack of vertical resolution in satellite ash column data can result in a poor estimation of the injection...journal article 2016
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Fu, Guangliang (author), Heemink, A.W. (author), Lu, S. (author), Segers, AJ (author), Weber, Konradin (author), Lin, H.X. (author)The forecast accuracy of distal volcanic ash clouds is important for providing valid aviation advice during volcanic ash eruption. However, because the distal part of volcanic ash plume is far from the volcano, the influence of eruption information on this part becomes rather indirect and uncertain, resulting in inaccurate volcanic ash forecasts...journal article 2016
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Fu, Guangliang (author), Lin, H.X. (author), Heemink, A.W. (author), Lu, S. (author), Segers, Arjo (author), van Velzen, C. (author), Lu, Tongchao (author), Xu, Shiming (author)In this study, we investigate a strategy to accelerate the data assimilation (DA) algorithm. Based on evaluations of the computational time, the analysis step of the assimilation turns out to be the most expensive part. After a study of the characteristics of the ensemble ash state, we propose a mask-state algorithm which records the sparsity...journal article 2017
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Lu, S. (author), Heemink, A.W. (author), Lin, H.X. (author), Segers, Arjo (author), Fu, Guangliang (author)Remote sensing, as a powerful tool for monitoring atmospheric phenomena, has been playing an increasingly important role in inverse modeling. Remote sensing instruments measure quantities that often combine several state variables as one. This creates very strong correlations between the state variables that share the same observation variable....journal article 2017
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Jin, J. (author), Segers, Arjo (author), Heemink, A.W. (author), Yoshida, Mayumi (author), Han, Wei (author), Lin, H.X. (author)Aerosol optical depths (AODs) from the new Himawari-8 satellite instrument have been assimilated in a dust simulation model over East Asia. This advanced geostationary instrument is capable of monitoring the East Asian dust storms which usually have great spatial and temporal variability. The quality of the data has been verified through a...journal article 2019
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Jin, J. (author), Lin, H.X. (author), Segers, Arjo (author), Xie, Yu (author), Heemink, A.W. (author)Data assimilation algorithms rely on a basic assumption of an unbiased observation error. However, the presence of inconsistent measurements with nontrivial biases or inseparable baselines is unavoidable in practice. Assimilation analysis might diverge from reality since the data assimilation itself cannot distinguish whether the differences...journal article 2019
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- Segers, A.J. (author), Heemink, A.W. (author), Verlaan, M. (author), Van Loon, M. (author) report 2000
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