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  • 1
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    The FESOM model family - recent applications (2017)
    In:  EPIC3IMUM 2017, Stanford, California, 2017-08-29-2017-09-01
    Details
    Publication Date: 2017-09-15
    Description: This contribution focuses on two applications of the FESOM model family. On the one hand, recent runs with the finite volume code FESOM2 on large global meshes with regional focus are presented. FESOM's shallow water branch TsunAWI is the subject of the second part. TsunAWI, still based on finite elements, is used as an operational model in the Indonesia Tsunami Early Warning System (InaTEWS). InaTEWS derives tsunami forecasts in two different ways: from scenarios in a pre-computed database or from an on-the-fly simulation. The pre-computed scenarios are based on TsunAWI simulations with inundation on a triangular mesh with a resolution ranging from 20km in the deep ocean to 300m - 50m in coastal areas. The on-the-fly propagation model EasyWave (Andrey Babeyko, GFZ) solves the linear shallow water equations on a regular finite-difference grid with a resolution of about 1 km and the coast line as a vertical wall. EasyWave is used after a tsunami has been generated in an area not covered by the database or after seismic measurements show an earthquake mechanism not present in the database. As the numerical settings of both models are quite different, variations in the outputs are to be expected; nevertheless, the differences in the warning levels should not be too large for identical sources. In the current study, we systematically compare the warning products like estimated wave height and estimated time of arrival by the two approaches.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
    Format: application/pdf
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  • 2
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    Current status of TsunAWI contributions to the Indonesia Tsunami Early Warning System (InaTEWS) with a comparison of warning products from near-realtime easyWave and precomputed TsunAWI simulations (2018)
    In:  EPIC3UNESCO IOC Symposium: Advances in Tsunami Warning to Enhance Community Responses, Paris, 2018-02-12-2018-02-14
    Details
    Publication Date: 2018-02-17
    Description: Abstract: The Indonesia Tsunami Early Warning System delivers simulated tsunami forecasts in two different ways: either matching scenario(s) from a pre-computed database or running on-the-fly tsunami simulation. Recently, the database has been extended considerably taking into account additional source regions not covered in earlier stages of the system. In this contribution, we present the current status of the data base coverage as well as a study investigating the warning products obtained by the two modeling approaches. The pre-computed tsunami scenarios are based on the finite element model TsunAWI that employs a triangular mesh with resolution ranging from 20km in deep ocean to 300m in coastal areas and to as much as 50m in some highly resolved areas. TsunAWI solves the nonlinear shallow water equations and contains a wetting-drying inundation scheme. The on-the-fly propagation model easyWave solves the linear shallow water equations on a regular finite-difference grid with a resolution of about 1 km and utilizes several simple options to estimate coastal impact. This model is used for forecasting after a tsunami has been generated in an area not covered by the database or after a moment tensor solution shows an earthquake focal mechanism not present in the database. Since warning products like estimated wave height (EWH) and estimated time of arrival (ETA) along the coast are based on modeling results, it is crucial to compare the resulting forecasted warning levels obtained by the two approaches. Resolutions and numerical settings of both models are quite different, therefore variations in the resulting outputs are to be expected; nevertheless, the extent of differences in warning levels should not be too large for identical sources. In the present study, we systematically investigate differences in resulting warning products along InaTEWS forecast points facing the Sunda arc.  Whereas the finite-element mesh of TsunAWI covers the coast up to a terrain height of 50m and warning products have been pre-calculated directly in the forecast points, easyWave offers several options for their approximation including projections from offshore grid points or vertical wall. Differences and potential reasons for variations of warning products like the role of bathymetry resolution as well as the general approach for the assessment of EWH and ETA for different modeling frameworks are discussed.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
    Format: application/pdf
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  • 3
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    Extending the database of pre-computed tsunami simulations for the Indonesian tsunami early warning system (InaTEWS) (2017)
    In:  EPIC3ITS 2017 - International Tsunami Symposium, Bali - Flores, Indonesia, 2017-08-21-2017-08-25
    Details
    Publication Date: 2018-01-30
    Description: The ultimate goal of establishing InaTEWS is to reduce as much as possible the victims due to tsunami. Since 2008, InaTEWS has been operated by BMKG and has shown its performance, proven by its ability to reliably detect and analyze earthquakes within 5 minutes, produce early warnings, and disseminate the products promptly. One of the important elements in the tsunami early warning is the availability of a pre-calculated tsunami database. The tsunami database provides the information about estimated tsunami arrival times and heights in the affected area. In InaTEWS, the pre-calculated tsunami database is integrated into a decision support system that helps operators to take decisions in issuing tsunami warnings. In 2012, this system has been equipped with a database of tsunami simulations covering the Sunda Zone. Obviously this coverage is not sufficient to account for the Eastern part of Indonesia that is also prone to tsunami. As a result that stage of the tsunami result needs to be extended. A project involving BMKG, Alfred Wegener Institute (AWI) and DMInnovation started in May 2015 to strengthen the decision support system of InaTEWS. Several workshops at BMKG were carried out to expand the scenario database in eastern Indonesia. The basis for tsunami scenario computations is the unstructured mesh finite-element numerical model TsunAWI developed by AWI. It is based on non-linier shallow water theory. The discretization scheme is based on finite elements with the mesh generation (covering the whole Indonesian region) that allows for an accurate local resolution along the coast while keeping coarse resolution in the deep ocean. The discretization of faults as a source for tsunami model was developed by Geoscience Australia / DMInnovation. The tsunami scenarios have been calculated for 13 additional source zones, on total 11949 scenarios in eastern Indonesia. The data products of all these scenarios are integrated to the decision support system TOAST developed by gempa GmbH via the Scenario Database Interface TsunDaBI. The sensitivity of the scenarios database with respect to the epicenter density and magnitude variation needed to be assessed, to test as to whether the current tsunami database is already sufficient or additional simulations are needed. In total the scenario repository was extended from 4580 to more than 16000 simulations. The extended tsunami database is expected to improve the tsunami warning bulletin in East Indonesia considerably.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
    Format: application/pdf
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  • 4
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    Comparison of Modeling Approaches and Derived Warning Products in the Framework of the Indonesia Tsunami Early Warning System (InaTEWS) (2018)
    In:  EPIC3AOGS EGU Joint Conference, Tagaytay, Philippines, 2018-02-04-2018-02-08
    Details
    Publication Date: 2018-02-22
    Description: The Indonesia Tsunami Early Warning System estimates tsunami impact by two methods: either matching scenarios from a pre-computed database or running realtime tsunami simulations. The database scenarios are based on the finite element model TsunAWI using a triangular mesh with resolution ranging from 20km in deep ocean to 300m in coastal areas and up to 50m in some highly-resolved areas. TsunAWI solves the nonlinear shallow water equations and contains an inundation scheme. The on-the-fly propagation model easyWave solves the linear shallow water equations on a regular finite-difference grid with a resolution of about 1km and utilizes several options to estimate coastal impact. This model is used for potential tsunami events in areas not covered by the database. Warning products like estimated wave height (EWH) and estimated time of arrival (ETA) along the coast are based on modeling results. Therefore comparisons of the forecasted warning levels for the two approaches are crucial. Resolutions and numerical settings of both models differ, therefore variations in the resulting outputs are to be expected; nevertheless, the extent of differences in warning levels should not be too large for identical sources. In the present study, we systematically investigate differences in warning products along forecast points facing the Sunda arc. TsunAWI determines warning products are directly in the coastal forecast points, easyWave offers several options for their approximation including projections from offshore grid points. Differences and potential reasons for variations of warning products like the role of bathymetry, resolution as well as the general approach for the assessment of EWH and ETA for different modeling frameworks are discussed.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
    Format: application/pdf
    Location Call Number Limitation Availability
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    PAPER (OA)
  • 5
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    Comparison of modeling approaches and the resulting warning products in the framework of the Indonesia Tsunami Early Warning System (InaTEWS) (2017)
    In:  EPIC3ITS2017 - International Tsunami Symposium, Bali - Flores, Indonesia, 2017-08-21-2017-08-25
    Details
    Publication Date: 2017-09-06
    Description: The Indonesia Tsunami Early Warning System delivers simulated tsunami forecasts in two different ways: either matching scenario(s) from a pre-computed database or running on-the-fly tsunami simulation. The pre-computed tsunami scenarios are based on the finite element model TsunAWI that employs a triangular mesh with resolution ranging from 20km in deep ocean to 300m in coastal areas and to as much as 50m in some highly resolved areas. TsunAWI solves the nonlinear shallow water equations and contains a wetting-drying inundation scheme. The on-the-fly propagation model easyWave solves the linear shallow water equations on a regular finite-difference grid with a resolution of about 1 km and utilizes several simple options to estimate coastal impact. This model is used for forecasting after a tsunami has been generated in an area not covered by the database or after a moment tensor solution shows an earthquake focal mechanism not present in the database. Since warning products like estimated wave height (EWH) and estimated time of arrival (ETA) along the coast are based on modeling results, it is crucial to compare the resulting forecasted warning levels obtained by the two approaches. Resolutions and numerical settings of both models are quite different, therefore variations in the resulting outputs are to be expected; nevertheless, the extent of differences in warning levels should not be too large for identical sources. In the present study, we systematically investigate differences in resulting warning products along InaTEWS forecast points facing the Sunda arc. Whereas the finite-element mesh of TsunAWI covers the coast up to a terrain height of 50m and warning products have been pre-calculated directly in the forecast points, easyWave offers several options for their approximation including projections from offshore grid points or vertical wall. Differences and potential reasons for variations of warning products like the role of bathymetry resolution as well as the general approach for the assessment of EWH and ETA for different modeling frameworks are discussed in this contribution.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
    Format: application/pdf
    Location Call Number Limitation Availability
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    PAPER (OA)
  • 6
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    The Tsunami Scenario Database of the Indonesia Tsunami Early Warning System (InaTEWS): Evolution of the Coverage and the Involved Modeling Approaches (2019)
    In:  EPIC3Pure Appl. Geophys.
    Details
    Publication Date: 2019-12-20
    Description: This study reports on recent developments of the Indonesia Tsunami Early Warning System (InaTEWS), specifically the tsunami modeling components used in the system. It is a dual system: firstly, InaTEWS operates a high-resolution scenario database pre-computed with the finite element model TsunAWI; running in parallel, the system also contains a supra real-time modeling component based on the GPU-parallelized linear long-wave model easyWave, capable of dealing with events outside the database coverage. The evolution of the tsunami scenario database over time is covered in the first sections also touching on the involved capacity building efforts. Starting with a coverage of just the Sunda Arc region, the database now includes scenarios for 15 fault zones. The study is augmented by an investigation of warning products used for early warning; the estimated wave height (EWH) and the estimated time of arrival (ETA). These parameters are determined by easyWave and TsunAWI with model specific approaches. Since the numerical setup of the two models is very different, the extent of variations in warning products is investigated for a number of scenarios, where both pure database scenarios and applications to real events are considered. Finally, the performance of the system in past tsunami events is reviewed to point out major system updates.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , peerRev
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  • 7
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    Vulnerability of lowland and upland orchids in their spatially response to climate change and land cover change (2024)
    In:  Ecological Informatics vol. 80 no. 102534
    Details
    Publication Date: 2024-05-18
    Description: Climate change and land cover change often interactively affect plant species distributions. This study addresses the vulnerability of lowland and upland orchids to climate change and land cover change. Endemic orchids of New Guinea were grouped into four classes (lowland epiphyte, lowland terrestrial, upland epiphyte, upland terrestrial) based on their life form and elevation range. Forty occurrence records of endemic orchids were selected for each class, totaling 160 occurrence records. Ensemble modelling combining two machine learning algorithms was used to generate predictive current and future suitable areas for orchid classes. Model performance was evaluated using the AUC and TSS metrics. Suitable areas for both lowland and upland orchids (epiphyte and terrestrial) were predicted decrease in the future due to climate change and land cover change. The loss of suitable areas for upland terrestrial orchids was predicted to be most significant in the worst-case climate change scenario (SSP 5–8.5). Both lowland and upland orchids (epiphyte and terrestrial) tend to shift to higher elevation ranges from the present distributions. The predictive models have AUC values 〉0.90 and TSS value 〉0.80, indicating the models have excellent potential for predicting the impact of climate change and land cover change on orchid distributions.
    Keywords: Ensemble model ; Climate change ; Species distribution model ; Orchids ; Lowland ; Upland ; New Guinea
    Repository Name: National Museum of Natural History, Netherlands
    Type: info:eu-repo/semantics/article
    Format: application/pdf
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