Physical Sciences and Mathematics Commons^™

High Spatial And Temporal Resolution Census Data Reveals Communities At Risk Along The Wildland-Urban Interface (Wui) In California, Usa, Jessica E. Viner, Slade T. Laszewski, Wesley Ho, Justin Ewoldt, Pionnah Gregorio, Liz Lyon, Brian Hoover, Shenyue Jia

Mathematics, Physics, and Computer Science Faculty 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 …

Changes In Fire Weather Climatology Under 1.5 ◦C And 2.0 ◦C Warming, Rackhun Son, Hyungjun Kim, Shih-Yu (Simon) Wang, Jee-Hoon Jeong, Sung-Ho Woo, Ji-Yoon Jeong, Byung-Doo Lee, Seung Hee Kim, Matthew Laplante, Chun-Geun Kwon, Jin-Ho Yoon

Mathematics, Physics, and Computer Science Faculty Articles and Research

The 2015 Paris Agreement led to a number of studies that assessed the impact of the 1.5 ◦C and 2.0 ◦C increases in global temperature over preindustrial levels. However, those assessments have not actively investigated the impact of these levels of warming on fire weather. In view of a recent series of high-profile wildfire events worldwide, we access fire weather sensitivity based on a set of multi-model large ensemble climate simulations for these low-emission scenarios. The results indicate that the half degree difference between these two thresholds may lead to a significantly increased hazard of wildfire in certain parts of …

Investigating The Lagged Relationship Between Smap Soil Moisture And Live Fuel Moisture In California, Usa, Shenyue Jia, Seung Hee Kim, Son V. Nghiem, Keun Hang S. Yang, Menas Kafatos

Mathematics, Physics, and Computer Science Faculty Articles and Research

Live fuel moisture (LFM), defined as the ratio between water in the fresh biomass out of the dry biomass, is a vital measurement of vegetation water content and flammability. In this study, we investigated the dynamics of in-situ measurement of LFM at all the active sites in California, USA and revealed the difference between evergreen forest and shrub/scrub, the two dominant land cover types in California's fire-prone regions. We found that LFM of evergreen forest responses to soil moisture increase later than shrub/scrub, due to a later occurrence of major precipitation, a lower air temperature, and the different plant physiology. …

A Feasibility Study On The Application Of Tvdi On Accessing Wildfire Danger In The Korean Peninsula, Kwang Nyun Kim, Seung Hee Kim, Myoung Soo Won, Keun Chang Jang, Won Jun Choi, Yun Gon Lee

Mathematics, Physics, and Computer Science Faculty Articles and Research

Wildfire is a major natural disaster affecting socioeconomics and ecology. Remote sensing data have been widely used to estimate the wildfire danger with an advantage of higher spatial resolution. Among the several wildfire related indices using remote sensing data, Temperature Vegetation Dryness Index (TVDI) assesses wildfire danger based on both Normalized Difference Vegetation Index (NDVI) and Land Surface Temperature (LST). Although TVDI has physical advantages by considering both weather and vegetation condition, previous studies have shown TVDI does not performed well compare to other wildfire related indices over the Korean Peninsula. In this study we have attempted multiple modification to …

Estimating Live Fuel Moisture Using Smap L-Band Radiometer Soil Moisture For Southern California, Usa, Shenyue Jia, Seung Hee Kim, Son V. Nghiem, Menas Kafatos

Mathematics, Physics, and Computer Science Faculty Articles and Research

Live fuel moisture (LFM) is a field-measured indicator of vegetation water content and a crucial observation of vegetation flammability. This study presents a new multi-variant regression model to estimate LFM in the Mediterranean ecosystem of Southern California, USA, using the Soil Moisture Active Passive (SMAP) L-band radiometer soil moisture (SMAP SM) from April 2015 to December 2018 over 12 chamise (Adenostoma fasciculatum) LFM sites. The two-month lag between SMAP SM and LFM was utilized either as steps to synchronize the SMAP SM to the LFM series or as the leading time window to calculate the accumulative SMAP SM. …

Estimation Of The Relationship Between Satellite-Derived Vegetation Indices And Live Fuel Moisture Towards Wildfire Risk In Southern California, Kristen Whitney, Seung Hee Kim, Shenyue Jia, Menas Kafatos

Mathematics, Physics, and Computer Science Faculty Articles and Research

Southern California possesses a Mediterranean climate having semi-arid to arid characteristics and contains shrubland areas at high risk to wildfire. To assess wildfire danger, fire agencies have been monitoring the moisture of vegetation, called live fuel moisture (LFM), using field-based sampling. Unfortunately, spatial and temporal resolution of live fuel moisture data are significantly limited because sampling is labor intensive. Remote sensing satellite data has been used to monitor vegetation moisture content and health of shrublands. Therefore, a potential approach to overcome the limitations of manual measurements of live fuel moisture is to use vegetation indices (VIs) derived from satellite data. …

Estimating Live Fuel Moisture In Southern California Using Remote Sensing Vegetation Water Content Proxies, Shenyue Jia, Seung Hee Kim, Son V. Nghiem, Wonhee Cho, Menas Kafatos

Mathematics, Physics, and Computer Science Faculty Articles and Research

Wildfires are a major ecological disturbance in Southern California and often lead to great destruction along the Wildland-Urban Interface. Live fuel moisture has been used as an important indicator of wildfire risk in measurements of vegetation water content. However, the limited field measurements of live fuel moisture in both time and space have affected the accuracy of wildfire risk estimations. Traditional estimation of live fuel moisture using remote sensing data was based on vegetation indices, indirect proxies of vegetation water content and subject to influence from weather conditions. In this study, we investigated the feasibility of estimating live fuel moisture …

Estimating Live Fuel Moisture From Modis Satellite Data For Wildfire Danger Assessment In Southern California Usa, Boksoon Myoung, Seung Hee Kim, Son V. Nghiem, Shenyue Jia, Kristen Whitney, Menas Kafatos

Mathematics, Physics, and Computer Science Faculty Articles and Research

The goal of the research reported here is to assess the capability of satellite vegetation indices from the Moderate Resolution Imaging Spectroradiometer onboard both Terra and Aqua satellites, in order to replicate live fuel moisture content of Southern California chaparral ecosystems. We compared seasonal and interannual characteristics of in-situ live fuel moisture with satellite vegetation indices that were averaged over different radial extents around each live fuel moisture observation site. The highest correlations are found using the Aqua Enhanced Vegetation Index for a radius of 10 km, independently verifying the validity of in-situ live fuel moisture measurements over a large …