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Chapman University

Institute for ECHO Articles and Research

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Articles 1 - 13 of 13

Full-Text Articles in Physical Sciences and Mathematics

Kinematic And Dynamic Structure Of The 18 May 2020 Squall Line Over South Korea, Wishnu Agum Swastiko, Chia-Lun Tsai, Seung Hee Kim, Gyuwon Lee Apr 2024

Kinematic And Dynamic Structure Of The 18 May 2020 Squall Line Over South Korea, Wishnu Agum Swastiko, Chia-Lun Tsai, Seung Hee Kim, Gyuwon Lee

Institute for ECHO Articles and Research

The diagonal squall line that passed through the Korean Peninsula on the 18 May 2020 was examined using wind data retrieved from multiple Doppler radar synthesis focusing on its kinematic and dynamic aspects. The low-level jet, along with warm and moist air in the lower level, served as the primary source of moisture supply during the initiation and formation process. The presence of a cold pool accompanying the squall line played a role in retaining moisture at the surface. As the squall line approached the Korean Peninsula, the convective bands in the northern segment (NS) and southern segment (SS) of …


Nowcasting Heavy Rainfall With Convolutional Long Short-Term Memory Networks: A Pixelwise Modeling Approach, Yi Victor Wang, Seung Hee Kim, Geunsu Lyu, Choeng-Lyong Lee, Soorok Ryu, Gyuwon Lee, Ki-Hong Min, Menas C. Kafatos Apr 2024

Nowcasting Heavy Rainfall With Convolutional Long Short-Term Memory Networks: A Pixelwise Modeling Approach, Yi Victor Wang, Seung Hee Kim, Geunsu Lyu, Choeng-Lyong Lee, Soorok Ryu, Gyuwon Lee, Ki-Hong Min, Menas C. Kafatos

Institute for ECHO Articles and Research

The recent decades have seen an increasing academic interest in leveraging machine learning approaches to nowcast, or forecast in a highly short-term manner, precipitation at a high resolution, given the limitations of the traditional numerical weather prediction models on this task. To capture the spatiotemporal associations of data on input variables, a deep learning (DL) architecture with the combination of a convolutional neural network and a recurrent neural network can be an ideal design for nowcasting rainfall. In this study, a long short-term memory (LSTM) modeling structure is proposed with convolutional operations on input variables. To resolve the issue of …


Yearly Population Data At Census Tract Level Revealed That More People Are Now Living In Highly Fire-Prone Zones In California, Usa, Slade Lazeweski, Shenyue Jia, Jessica E. Viner, Wesley Ho, Brian Hoover, Seung Hee Kim, Menas C. Kafatos Mar 2024

Yearly Population Data At Census Tract Level Revealed That More People Are Now Living In Highly Fire-Prone Zones In California, Usa, Slade Lazeweski, Shenyue Jia, Jessica E. Viner, Wesley Ho, Brian Hoover, Seung Hee Kim, Menas C. Kafatos

Institute for ECHO Articles and Research

In California (CA), the wildland-urban interface (WUI) faces escalating challenges due to surging population and real estate development. This study evaluates communities along CA's WUI that have witnessed substantial population growth from 2010 to 2021, utilizing demographic data and the 2020 WUI boundaries by the University of Wisconsin-Madison SILVIS Lab. Employing the Mann-Kendall test, we analyze yearly population trends for each census tract along the CA WUI and assess their significance. House ownership, affordability, and wildfire risk are examined as potential drivers of this demographic shift. Our findings indicate that 12.7% of CA's total population now resides in census tracts …


Verifying Empirical Predictive Modeling Of Societal Vulnerability To Hazardous Events: A Monte Carlo Experimental Approach, Yi Victor Wang, Seung Hee Kim, Menas C. Kafatos Aug 2023

Verifying Empirical Predictive Modeling Of Societal Vulnerability To Hazardous Events: A Monte Carlo Experimental Approach, Yi Victor Wang, Seung Hee Kim, Menas C. Kafatos

Institute for ECHO Articles and Research

With the emergence of large amounts of historical records on adverse impacts of hazardous events, empirical predictive modeling has been revived as a foundational paradigm for quantifying disaster vulnerability of societal systems. This paradigm models societal vulnerability to hazardous events as a vulnerability curve indicating an expected loss rate of a societal system with respect to a possible spectrum of intensity measure (IM) of an event. Although the empirical predictive models (EPMs) of societal vulnerability are calibrated on historical data, they should not be experimentally tested with data derived from field experiments on any societal system. Alternatively, in this paper, …


Feasibility Analysis Of Aeronet Lunar Aod For Nighttime Particulate Matter Estimation, Kwang Nyun Kim, Seung Hee Kim, Sang Seo Park, Yun Gon Lee May 2023

Feasibility Analysis Of Aeronet Lunar Aod For Nighttime Particulate Matter Estimation, Kwang Nyun Kim, Seung Hee Kim, Sang Seo Park, Yun Gon Lee

Institute for ECHO Articles and Research

Several studies have attempted to estimate particulate matter (PM) concentrations using aerosol optical depth (AOD), based on AOD and PM relationships. Owing to the limited availability of nighttime AOD data, PM estimation studies using AOD have focused on daytime. Recently, the Aerosol Robotic Network (AERONET) produced nighttime AOD, called lunar AOD, providing an opportunity to estimate nighttime PM. Nighttime AOD measurements are particularly important as they help fill gaps in our understanding of aerosol variability and its impact on the atmosphere, as there are significant variations in AOD between day and night. In this study, the relationship between lunar AOD …


Equivalent Hazard Magnitude Scale, Yi Victor Wang, Antonia Sebastian Dec 2022

Equivalent Hazard Magnitude Scale, Yi Victor Wang, Antonia Sebastian

Institute for ECHO Articles and Research

Hazard magnitude scales are widely adopted to facilitate communication regarding hazard events and the corresponding decision making for emergency management. A hazard magnitude scale measures the strength of a hazard event considering the natural forcing phenomena and the severity of the event with respect to average entities at risk. However, existing hazard magnitude scales cannot be easily adapted for comparative analysis across different hazard types. Here, we propose an equivalent hazard magnitude scale to measure the hazard strength of an event across multiple types of hazards. We name the scale the Gardoni Scale after Professor Paolo Gardoni. We design the …


Relative Importance Of Radar Variables For Nowcasting Heavy Rainfall: A Machine Learning Approach, Yi Victor Wang, Seung Hee Kim, Geunsu Lyu, Choeng-Lyong Lee, Gyuwon Lee, Ki-Hong Min, Menas C. Kafatos Dec 2022

Relative Importance Of Radar Variables For Nowcasting Heavy Rainfall: A Machine Learning Approach, Yi Victor Wang, Seung Hee Kim, Geunsu Lyu, Choeng-Lyong Lee, Gyuwon Lee, Ki-Hong Min, Menas C. Kafatos

Institute for ECHO Articles and Research

Highly short-term forecasting, or nowcasting, of heavy rainfall due to rapidly evolving mesoscale convective systems (MCSs) is particularly challenging for traditional numerical weather prediction models. To overcome such a challenge, a growing number of studies have shown significant advantages of using machine learning (ML) modeling techniques with remote sensing data, especially weather radar data, for high-resolution rainfall nowcasting. To improve ML model performance, it is essential first and foremost to quantify the importance of radar variables and identify pertinent predictors of rainfall that can also be associated with domain knowledge. In this study, a set of MCS types consisting of …


Crisisready's Novel Framework For Transdisciplinary Translation: Case-Studies In Wildfire And Hurricane Response, Andrew Schroeder, Caleb Dresser, Akash Yadav, Jennifer Chan, Shenyue Jia, Caroline Buckee, Satchit Balsari Dec 2022

Crisisready's Novel Framework For Transdisciplinary Translation: Case-Studies In Wildfire And Hurricane Response, Andrew Schroeder, Caleb Dresser, Akash Yadav, Jennifer Chan, Shenyue Jia, Caroline Buckee, Satchit Balsari

Institute for ECHO Articles and Research

Extreme weather events including wildfires and hurricanes are becoming increasingly hazardous due to climate change, and often result in transient or permanent population displacements. Disaster-related disruptions in infrastructure, workforce, wages, and social networks can combine with population displacements to result in interruptions in health care access and prolonged impacts on morbidity and mortality. The data needed to make health systems and emergency management approaches more resilient to these hazards, and more responsive to the needs of affected populations, are sequestered in silos across private corporations and public agencies. In two case studies, we describe how our research team at CrisisReady …


Meteorological Characteristics Of Fog Events In Korean Smart Cities And Machine Learning Based Visibility Estimation, Jaemin Kim, Seung Hee Kim, Hyun Woo Seo, Yi Victor Wang, Yun Gon Lee May 2022

Meteorological Characteristics Of Fog Events In Korean Smart Cities And Machine Learning Based Visibility Estimation, Jaemin Kim, Seung Hee Kim, Hyun Woo Seo, Yi Victor Wang, Yun Gon Lee

Institute for ECHO Articles and Research

To address various urban issues such as fine dust, traffic congestion, and water shortage caused by rapid urbanization, a national pilot Smart City is planned in two Korean cities, Sejong and Busan. As weather data is crucial for improving the environment and operating future transportation while constructing a smart city, preparing for future weather disasters by analyzing the characteristics of various meteorological phenomena in the planned development area is necessary. This study analyzed the fog generation characteristics for the period of 2016–2020 at the automatic weather system sites of the Korea Meteorological Administration in Sejong and Busan, and the characteristics …


Murphy Scale: A Locational Equivalent Intensity Scale For Hazard Events, Yi Victor Wang, Antonia Sebastian May 2022

Murphy Scale: A Locational Equivalent Intensity Scale For Hazard Events, Yi Victor Wang, Antonia Sebastian

Institute for ECHO Articles and Research

Empirical cross-hazard analysis and prediction of disaster vulnerability, resilience, and risk requires a common metric of hazard strengths across hazard types. In this paper, the authors propose an equivalent intensity scale for cross-hazard evaluation of hazard strengths of events for entire durations at locations. The proposed scale is called the Murphy Scale, after Professor Colleen Murphy. A systematic review and typology of hazard strength metrics is presented to facilitate the delineation of the defining dimensions of the proposed scale. An empirical methodology is introduced to derive equivalent intensities of hazard events on a Murphy Scale. Using historical data on …


High Spatial And Temporal Resolution Census Data Reveal Communities At Risk Along The Wildland-Urban Interface (Wui) In California, Usa, Shenyue Jia, Slade Lazeweski, Jessica E. Viner, Wesley Ho, Brian Hoover May 2022

High Spatial And Temporal Resolution Census Data Reveal Communities At Risk Along The Wildland-Urban Interface (Wui) In California, Usa, Shenyue Jia, Slade Lazeweski, Jessica E. Viner, Wesley Ho, Brian Hoover

Institute for ECHO Articles and Research

We tracked census tract level population change along California's wild land-urban interface (WUI) during the past decade (2010-2019), an ecological sensitive region transitioning from developed land to wilderness. Our results from Mann-Kendall analysis, a method employed for monotonic trend detection showed that about one-third (29.1%) of census tracts in California’s WUI have seen a significant population increase from 2010 to 2019, affecting 12.7% population in California. The population increase along WUI is largely driven by the sixteen counties in the San Francisco Bay Area (10) and Southern California (6). We also found that higher proportion of WUI residents in Bay …


Surface Urban Heat Island In South Korea’S New Towns With Different Urban Planning, Kyungil Lee, Yoonji Kim, Hyun Chan Sung, Seung Hee Kim, Seong Woo Jeon Apr 2022

Surface Urban Heat Island In South Korea’S New Towns With Different Urban Planning, Kyungil Lee, Yoonji Kim, Hyun Chan Sung, Seung Hee Kim, Seong Woo Jeon

Institute for ECHO Articles and Research

A new town is strategically built within a short period compared to naturally developed cities. It is considered an appropriate study area for analyzing the urban climate problems such as surface urban heat islands (SUHIs) that is differently generated according to urban planning and development. In this study, we suggest comprehensive method for determining and comparing changes in surface UHI distribution during 1989–2048 in two new towns with different urban planning. First, a substantial increase in built-up areas was observed from 1989 (< 5%) to 2018 (> 40%) in both new towns. However, SUHI phenomenon-increasing patterns were different of about 12.25% depending on urban …


Assessment Of Aerosol Optical Depth Under Background And Polluted Conditions Using Aeronet And Viirs Datasets, Mijin Kim, Seung Hee Kim, Woogyung Vincent Kim, Yun Gon Lee, Jhoon Kim, Menas C. Kafatos Oct 2020

Assessment Of Aerosol Optical Depth Under Background And Polluted Conditions Using Aeronet And Viirs Datasets, Mijin Kim, Seung Hee Kim, Woogyung Vincent Kim, Yun Gon Lee, Jhoon Kim, Menas C. Kafatos

Institute for ECHO Articles and Research

We investigated aerosol optical depth (AOD) under background and polluted conditions using Aerosol Robotic Network (AERONET) and Visible Infrared Imaging Radiometer Suite (VIIRS) observations. The AOD data were separated into background, high, and median AOD (BAOD, HAOD, and MAOD, respectively) based on the cumulative AOD distribution at each point and then their spatiotemporal variations were analyzed. Persistent pollutant emissions from industrial activity in South Asia (SUA) and Northeast Asia (NEA) produced the highest BAOD values. Gridded-BAODs obtained from VIIRS Deep Blue AOD products showed widespread high-level BAOD over the oceans associated with transport from dust and biomass burning events. The …