The purpose of this study is to understand the characteristics of the spatial distribution of forest fire occurrences with the local indicators of temporal burstiness in Korea. Forest fire damage data were produced in the form of areas by combining the forest fire damage ledger information with VIIRS-based forest fire occurrence data. Then, detrended fluctuation analysis and the local indicator of temporal burstiness were applied. In the results, the forest fire occurrence follows a self-organized criticality mechanism, and the temporal irregularities of fire occurrences exist. When the forest fire occurrence time series in Gyeonggi-do Province, which had the highest value of the local indicator of temporal burstiness, was checked, it was found that the frequency of forest fires was increasing at intervals of about 10 years. In addition, when the frequencies of forest fires and the spatial distribution of the local indicators of forest fire occurrences were compared, it was found that there were spatial differences in the occurrence of forest fires. This study is meaningful in that it analyzed the time series characteristics of the distribution of forest fires in Korea to understand that forest fire occurrences have long-term temporal correlations and identified areas where the temporal irregularities of forest fire occurrences are remarkable with the local indicators of temporal burstiness.

This study examined meteorological and streamflow droughts for the period from 1951 to 2006 using the Milwaukee River basin in Wisconsin as the study area in an effort to improve the understanding of drought propagation. Specifically, this study aimed to answer the following research questions: (1) What are the temporal trends of meteorological and streamflow droughts identified by drought indicators? (2) How do the drought indicators manifest drought propagation? Meteorological droughts were identified using the Effective Drought Index (EDI), and streamflow droughts were identified using a threshold-level approach. The intensity and duration of both types of drought were found to have decreased over time, most likely due to increasing precipitation. Therefore, in the study area, and likely in the larger region, drought has become of less concern. The propagation of meteorological drought into streamflow drought was detected generally after moderate and severe sequences of negative EDI that eventually led to extreme meteorological drought events. The study finds that both EDI and the threshold-level approach are effective in diagnosing meteorological and streamflow drought events of all durations.

Today, unpredictable damage can result from extreme weather such as heat waves and floods. This damage makes communities that cannot respond quickly to disasters more vulnerable than cities. Thus, people living in such communities can easily become isolated, which can cause unavoidable loss of life or property. In the meantime, many disaster management studies have been conducted, but studies on effective disaster response for areas surrounded by mountains or with weak transportation infrastructure are very rare. To fill the gap, this research aimed at developing an automated analysis tool that can be directly used for disaster response and recovery by identifying in real time the communities at risk of isolation using a web-based geographic information system (GIS) application. We first developed an algorithm to automatically detect communities at risk of isolation due to disaster. Next, we developed an analytics module to identify buildings and populations within the communities and efficiently place at-risk residents in shelters. In sum, the analysis tool developed in this study can be used to support disaster response decisions regarding, for example, rescue activities and supply of materials by accurately detecting isolated areas when a disaster occurs in a mountainous area where communication and transportation infrastructure is lacking.

Hydrological droughts are important for agriculture and other human activities such as navigation and groundwater pumping, so it is necessary to understand their characteristics at various temporal and spatial scales. This study aims to examine the characteristics of hydrological droughts and their propagation from meteorological droughts across Wisconsin. Hydrological droughts were identified for twenty-four U.S. Geological Survey streamflow monitoring sites using the 20th percentile threshold level for each calendar day. Meteorological droughts were identified in the same way using daily precipitation data. Drought events of both types were identified for the period from 1980 to 2018, and the drought in 2012 was examined in detail. Our results indicate that (1) unlike meteorological droughts, hydrological droughts tend to occur more frequently in recent years; (2) characteristics of hydrological droughts are not correlated with those of meteorological droughts or annual precipitation; (3) there are generally three drought regions in Wisconsin showing different drought trends and propagation characteristics; and (4) groundwater withdrawal from unconfined aquifers has exacerbated hydrological droughts. In conclusion, hydrological droughts have become less synchronous with meteorological droughts, which will make drought early warning more challenging. The study sheds light on drought characteristics and propagation in relation to catchment characteristics and human activities.