scholarly journals Correction to: High-resolution flow simulation in Typhoon 21, 2018: massive loss of submerged macrophytes in Lake Biwa

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Satoshi Nakada ◽  
Hiroki Haga ◽  
Maho Iwaki ◽  
Kohji Mabuchi ◽  
Noriko Takamura
Keyword(s):  
High Resolution ◽  
Lake Biwa ◽  
Submerged Macrophytes ◽  
Flow Simulation

scholarly journals High-Resolution Flow-Simulation in Typhoon 21, 2018: Massive Loss of Submerged Macrophytes in Lake Biwa

2020 ◽  
Author(s):  
Satoshi Nakada ◽  
Hiroki Haga ◽  
Maho Iwaki ◽  
Keisuke Hatano ◽  
Kohji Mabuchi ◽  
...  
Keyword(s):  
High Resolution ◽  
Water Level ◽  
Lake Biwa ◽  
Submerged Macrophytes ◽  
Circulation Model ◽  
Climate Change Scenarios ◽  
The South ◽  
Fluid Force ◽  
South Basin ◽  
Massive Outflow

Abstract Global activities of typhoons and hurricanes are gradually changing, and these storms can drastically affect lake ecosystems through the recession of submerged macrophytes that regulate the water quality in lakes. Using an echosounder, we captured the short-term, massive loss of submerged macrophytes attributed to the abnormal fluctuation of the water level induced by the approach of a catastrophic super typhoon in the south basin of Lake Biwa, Japan. This paper investigates the physical processes responsible for the loss of vegetation using a high-resolution circulation model in Lake Biwa as a pilot study area. The circulation model was coupled with dynamical models of the fluid force and erosion acting on the vegetation. Our simulation successfully reproduced the water level fluctuation and high-speed current (torrent) generated by the typhoon gale. The simulated results demonstrate that the fluid force driven by the gale-induced torrent uprooted submerged macrophytes during the typhoon approach and that this fluid force (rather than erosion) caused the outflow of vegetation. As a result, this uprooting attributed to the fluid force induced the massive loss of submerged macrophytes in a large area of the south basin, which might have increased primary production and reduced the stock of fish such as bluegill in the lake. Our approach is practical for evaluating changes in lake environments attributed to the massive outflow of submerged macrophytes under various climate change scenarios. (227 words)

scholarly journals High-resolution flow simulation in Typhoon 21, 2018: massive loss of submerged macrophytes in Lake Biwa

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Nakada Satoshi ◽  
Haga Hiroki ◽  
Iwaki Maho ◽  
Mabuchi Kohji ◽  
Takamura Noriko
Keyword(s):  
High Resolution ◽  
Water Level ◽  
High Speed ◽  
Lake Biwa ◽  
Submerged Macrophytes ◽  
Circulation Model ◽  
Climate Change Scenarios ◽  
Fluid Force ◽  
Southern Basin ◽  
Massive Outflow

AbstractThe global activities of typhoons and hurricanes are gradually changing, and these storms can drastically affect lake ecosystems through the recession of submerged macrophytes that regulate the water quality in lakes. Using an echosounder, we captured the short-term, massive loss of submerged macrophytes attributed to the abnormal fluctuation of the water level induced by the approach of a catastrophic super typhoon in the southern basin of Lake Biwa, Japan. This paper investigates the physical processes responsible for the loss of vegetation using a high-resolution circulation model in Lake Biwa as a pilot study area. The circulation model was coupled with dynamical models of the fluid force and erosion acting on the vegetation. Our simulation successfully reproduced the water level fluctuation and high-speed current (torrent) generated by the typhoon gale. The simulated results demonstrated that the fluid force driven by the gale-induced torrent uprooted submerged macrophytes during the typhoon approach and that this fluid force (rather than erosion) caused the outflow of vegetation. As a result, this uprooting attributed to the fluid force induced the massive loss of submerged macrophytes in a large area of the southern basin, which might have increased primary production and reduced the stock of fish such as bluegill in the lake. Our model can estimate the reduction in the macrophyte height within the range of − 1.3 to − 0.4 m, suggesting that fluid forces greater than the time-averaged value (1.24 × 10−4 N) were available. Flow speeds of approximately 0.8 m/s might be the critical value that induces the fluid force acting on the uprooting of the submerged macrophytes. Our approach is practical for evaluating changes in lake environments attributed to the massive outflow of submerged macrophytes under various climate change scenarios.

APPLICATION OF THE HIGH-RESOLUTION RANS/ILES TECHNOLOGY FOR FLOW SIMULATION AND THE NEARBY ACOUSTIC FIELD OF NEAR-WALL JETS AND MIXING LAYERS

2016 ◽  
Vol 47 (2) ◽  
pp. 159-183 ◽  
Author(s):  
Leonid Aleksandrovich Bendersky ◽  
Dmitriy Aleksandrovich Lyubimov ◽  
Irina Vasilevna Potekhina ◽  
Alena Eduardovna Fedorenko
Keyword(s):  
High Resolution ◽  
Acoustic Field ◽  
Flow Simulation ◽  
Mixing Layers ◽  
Wall Jets ◽  
Near Wall

scholarly journals 3-Dimensional modeling of 2014-Malin Landslide, Maharashtra using satellite-derived data: A quantitative approach to numerical simulation technique

2018 ◽  
Author(s):  
Shovan Lal Chattoraj ◽  
Prashant K. Champati ray ◽  
Sudhakar Pardeshi ◽  
Vikram Gupta ◽  
Yateesh Ketholia
Keyword(s):  
High Resolution ◽  
Debris Flow ◽  
Flow Simulation ◽  
Simulation Models ◽  
Quantitative Information ◽  
Simulation Technique ◽  
Maximum Height ◽  
Deccan Volcanic Province ◽  
South Indian ◽  
High Resolution Satellite Images

Abstract. Debris flows, a type of landslides, are not nowadays limited only to the periodic devastation of the geologically fragile Himalaya but also ubiquitous in weathered Deccan Volcanic Province of the cratonic south Indian peninsula. Comprehensive assessment of landslide hazard, pertinently, requires process-based modeling using simulation methods. Development of precipitation triggered debris flow simulation models of real events are still at a young stage in India, albeit, especially in tectonically less disturbed regions. A highly objective simulation technique has therefore been envisaged herein to model the debris flow run-out happened in Malin. This takes cues from a high- resolution DEM and other ancillary ground data including geotechnical and frictional parameters. The algorithm is based on Voellmy frictional (dry and turbulent frictional coefficients, μ and ξ respectively) parameters of debris flow with pre-defined release area identified on high-resolution satellite images like LISS-IV and Cartosat-1. The model provides critical quantitative information on flow 1) Velocity, 2) Height, 3) Momentum, and 4) Pressure along the entrainment path. The simulated velocity of about 16 m/s at mid-way the slide plummeted to 6.2 m/s at the base with intermittently increased and decreased values. The simulated maximum height was 3.9 m which gradually declined to 1.5 m near the bottom. The results can be beneficial in engineering intervention like the construction of check dams to digest the initial thrust of the flow and other remedial measures designed for vulnerable slope protection.

Echosounding observations of coverage, height, PVI, and biomass of submerged macrophytes in the southern basin of Lake Biwa, Japan

Limnology ◽  
2007 ◽  
Vol 8 (2) ◽  
pp. 95-102 ◽  
Author(s):  
Hiroki Haga ◽  
Taisuke Ohtsuka ◽  
Masanari Matsuda ◽  
Minako Ashiya
Keyword(s):  
Lake Biwa ◽  
Submerged Macrophytes ◽  
Southern Basin

scholarly journals Delineating wetland catchments and modeling hydrologic connectivity using lidar data and aerial imagery

2017 ◽  
Vol 21 (7) ◽  
pp. 3579-3595 ◽  
Author(s):  
Qiusheng Wu ◽  
Charles R. Lane
Keyword(s):  
High Resolution ◽  
Spatial Data ◽  
Overland Flow ◽  
Flow Simulation ◽  
Hierarchical Structures ◽  
Aerial Imagery ◽  
Lidar Data ◽  
Hydrologic Connectivity ◽  
Least Cost Path ◽  
Elevation Model

Abstract. In traditional watershed delineation and topographic modeling, surface depressions are generally treated as spurious features and simply removed from a digital elevation model (DEM) to enforce flow continuity of water across the topographic surface to the watershed outlets. In reality, however, many depressions in the DEM are actual wetland landscape features with seasonal to permanent inundation patterning characterized by nested hierarchical structures and dynamic filling–spilling–merging surface-water hydrological processes. Differentiating and appropriately processing such ecohydrologically meaningful features remains a major technical terrain-processing challenge, particularly as high-resolution spatial data are increasingly used to support modeling and geographic analysis needs. The objectives of this study were to delineate hierarchical wetland catchments and model their hydrologic connectivity using high-resolution lidar data and aerial imagery. The graph-theory-based contour tree method was used to delineate the hierarchical wetland catchments and characterize their geometric and topological properties. Potential hydrologic connectivity between wetlands and streams were simulated using the least-cost-path algorithm. The resulting flow network delineated potential flow paths connecting wetland depressions to each other or to the river network on scales finer than those available through the National Hydrography Dataset. The results demonstrated that our proposed framework is promising for improving overland flow simulation and hydrologic connectivity analysis.

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