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Zhang, Yuqing, Qinglong You, Guangxiong Mao, Changchun Chen, Xin Li i Jinhua Yu. "Flash Drought Characteristics by Different Severities in Humid Subtropical Basins: A Case Study in the Gan River Basin, China". Journal of Climate 34, nr 18 (wrzesień 2021): 7337–57. http://dx.doi.org/10.1175/jcli-d-20-0596.1.
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AbstractIt is essential to assess flash drought risk based on a reliable flash drought intensity (severity) index incorporating comprehensive information of the rapid decline (“flash”) in soil moisture toward drought conditions and soil moisture thresholds belonging to the “drought” category. In this study, we used the Gan River basin as an example to define a flash drought intensity index that can be calculated for individual time steps (pentads) during a flash drought period over a given grid (or station). The severity of a complete flash drought event is the sum of the intensity values during the flash drought. We explored the spatial and temporal characteristics of flash droughts with different grades based on their respective severities. The results show that decreases in total cloud cover, precipitation, and relative humidity, as well as increases in 500-hPa geopotential height, convective inhibition, temperature, vapor pressure deficit, and wind speed can create favorable conditions for the occurrence of flash droughts. Although flash droughts are relatively frequent in the central and southern parts of the basin, the severity is relatively high in the northern part of the basin due to longer duration. Flash drought severity shows a slightly downward trend due to decreases in frequency, duration, and intensity from 1961 to 2018. Extreme and exceptional flash droughts decrease significantly while moderate and severe flash droughts trend slightly upward. Flash drought severity appears to be more affected by the interaction between duration and intensity as the grade increases from mild to severe. The frequency and duration of flash droughts are higher in July–October. The southern part of the basin is more prone to moderate and severe flash droughts, while the northern parts of the basin are more vulnerable to extreme and exceptional flash droughts due to longer durations and greater severities than other parts. Moderate, severe, extreme, and exceptional flash droughts occurred at approximately 3–6-, 5–15-, 10–50-, and 30–200-yr intervals, respectively, based on the copula analysis.
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Zhang, Linqi, Yi Liu, Liliang Ren, Adriaan J. Teuling, Ye Zhu, Linyong Wei, Linyan Zhang i in. "Analysis of flash droughts in China using machine learning". Hydrology and Earth System Sciences 26, nr 12 (24.06.2022): 3241–61. http://dx.doi.org/10.5194/hess-26-3241-2022.
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Abstract. The term “flash drought” describes a type of drought with rapid onset and strong intensity, which is co-affected by both water-limited and energy-limited conditions. It has aroused widespread attention in related research communities due to its devastating impacts on agricultural production and natural systems. Based on a global reanalysis dataset, we identify flash droughts across China during 1979–2016 by focusing on the depletion rate of weekly soil moisture percentile. The relationship between the rate of intensification (RI) and nine related climate variables is constructed using three machine learning (ML) technologies, namely, multiple linear regression (MLR), long short-term memory (LSTM), and random forest (RF) models. On this basis, the capabilities of these algorithms in estimating RI and detecting droughts (flash droughts and traditional slowly evolving droughts) were analyzed. Results showed that the RF model achieved the highest skill in terms of RI estimation and flash drought identification among the three approaches. Spatially, the RF-based RI performed best in southeastern China, with an average CC of 0.90 and average RMSE of the 2.6 percentile per week, while poor performances were found in the Xinjiang region. For drought detection, all three ML technologies presented a better performance in monitoring flash droughts than in conventional slowly evolving droughts. Particularly, the probability of detection (POD), false alarm ratio (FAR), and critical success index (CSI) of flash drought derived from RF were 0.93, 0.15, and 0.80, respectively, indicating that RF technology is preferable in estimating the RI and monitoring flash droughts by considering multiple meteorological variable anomalies in adjacent weeks to drought onset. In terms of the meteorological driving mechanism of flash drought, the negative precipitation (P) anomalies and positive potential evapotranspiration (PET) anomalies exhibited a stronger synergistic effect on flash droughts compared to slowly developing droughts, along with asymmetrical compound influences in different regions of China. For the Xinjiang region, P deficit played a dominant role in triggering the onset of flash droughts, while in southwestern China, the lack of precipitation and enhanced evaporative demand almost contributed equally to the occurrence of flash drought. This study is valuable to enhance the understanding of flash droughts and highlight the potential of ML technologies in flash drought monitoring.
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Osman, Mahmoud, Benjamin F. Zaitchik, Hamada S. Badr, Jason Otkin, Yafang Zhong, David Lorenz, Martha Anderson i in. "Diagnostic Classification of Flash Drought Events Reveals Distinct Classes of Forcings and Impacts". Journal of Hydrometeorology 23, nr 2 (luty 2022): 275–89. http://dx.doi.org/10.1175/jhm-d-21-0134.1.
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Abstract Recent years have seen growing appreciation that rapidly intensifying flash droughts are significant climate hazards with major economic and ecological impacts. This has motivated efforts to inventory, monitor, and forecast flash drought events. Here we consider the question of whether the term “flash drought” comprises multiple distinct classes of event, which would imply that understanding and forecasting flash droughts might require more than one framework. To do this, we first extend and evaluate a soil moisture volatility–based flash drought definition that we introduced in previous work and use it to inventory the onset dates and severity of flash droughts across the contiguous United States (CONUS) for the period 1979–2018. Using this inventory, we examine meteorological and land surface conditions associated with flash drought onset and recovery. These same meteorological and land surface conditions are then used to classify the flash droughts based on precursor conditions that may represent predictable drivers of the event. We find that distinct classes of flash drought can be diagnosed in the event inventory. Specifically, we describe three classes of flash drought: “dry and demanding” events for which antecedent evaporative demand is high and soil moisture is low, “evaporative” events with more modest antecedent evaporative demand and soil moisture anomalies, but positive antecedent evaporative anomalies, and “stealth” flash droughts, which are different from the other two classes in that precursor meteorological anomalies are modest relative to the other classes. The three classes exhibit somewhat different geographic and seasonal distributions. We conclude that soil moisture flash droughts are indeed a composite of distinct types of rapidly intensifying droughts, and that flash drought analyses and forecasts would benefit from approaches that recognize the existence of multiple phenomenological pathways.
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Christian, Jordan I., Jeffrey B. Basara, Jason A. Otkin, Eric D. Hunt, Ryann A. Wakefield, Paul X. Flanagan i Xiangming Xiao. "A Methodology for Flash Drought Identification: Application of Flash Drought Frequency across the United States". Journal of Hydrometeorology 20, nr 5 (1.05.2019): 833–46. http://dx.doi.org/10.1175/jhm-d-18-0198.1.
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Abstract With the increasing use of the term “flash drought” within the scientific community, Otkin et al. provide a general definition that identifies flash droughts based on their unusually rapid rate of intensification. This study presents an objective percentile-based methodology that builds upon that work by identifying flash droughts using standardized evaporative stress ratio (SESR) values and changes in SESR over some period of time. Four criteria are specified to identify flash droughts: two that emphasize the vegetative impacts of flash drought and two that focus on the rapid rate of intensification. The methodology was applied to the North American Regional Reanalysis (NARR) to develop a 38-yr flash drought climatology (1979–2016) across the United States. It was found that SESR derived from NARR data compared well with the satellite-based evaporative stress index for four previously identified flash drought events. Furthermore, four additional flash drought cases were compared with the U.S. Drought Monitor (USDM), and SESR rapidly declined 1–2 weeks before a response was evident with the USDM. From the climatological analysis, a hot spot of flash drought occurrence was revealed over the Great Plains, the Corn Belt, and the western Great Lakes region. Relatively few flash drought events occurred over mountainous and arid regions. Flash droughts were categorized based on their rate of intensification, and it was found that the most intense flash droughts occurred over the central Great Plains, Corn Belt, and western Great Lakes region.
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Mo, Kingtse C., i Dennis P. Lettenmaier. "Precipitation Deficit Flash Droughts over the United States". Journal of Hydrometeorology 17, nr 4 (1.04.2016): 1169–84. http://dx.doi.org/10.1175/jhm-d-15-0158.1.
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Abstract Flash drought refers to relatively short periods of warm surface temperature and anomalously low and rapid decreasing soil moisture (SM). Based on the physical mechanisms associated with flash droughts, these events are classified into two categories: heat wave and precipitation P deficit flash droughts. In previous work, the authors have defined heat wave flash droughts as resulting from the confluence of severe warm air temperature Tair, which increases evapotranspiration (ET), and anomalously low and decreasing SM. Here, a second type of flash drought caused by precipitation deficits is explored. The authors term these events P-deficit flash droughts, which they associate with lack of P. Precipitation deficits cause ET to decrease and temperature to increase. The P-deficit flash droughts are analyzed based on observations of P, Tair, and SM and ET reconstructed using land surface models for the period 1916–2013. The authors find that P-deficit flash droughts are more common than heat wave flash droughts. They are about twice as likely to occur as heat wave flash droughts over the conterminous United States. They are most prevalent over the southern United States with maxima over the southern Great Plains and the Southwest, in contrast to heat wave flash droughts that are mostly likely to occur over the Midwest and the Pacific Northwest, where the vegetation cover is dense.
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Zhang, Yuqing, Qinglong You, Changchun Chen, Jing Ge i Muhammad Adnan. "Evaluation of Downscaled CMIP5 Coupled with VIC Model for Flash Drought Simulation in a Humid Subtropical Basin, China". Journal of Climate 31, nr 3 (18.01.2018): 1075–90. http://dx.doi.org/10.1175/jcli-d-17-0378.1.
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Abstract Compared to traditional drought events, flash droughts evolve rapidly during short-term extreme atmospheric conditions, with a lasting period of one pentad to several weeks. There are two main categories of flash droughts: the heat wave flash drought (HWFD), which is mainly caused by persistent high temperatures (heat waves), and the precipitation deficit flash drought (PDFD), which is mainly triggered by precipitation deficits. The authors’ previous research focused on the characteristics and causes of flash drought based on meteorological observations and Variable Infiltration Capacity (VIC) model simulations in a humid subtropical basin (Gan River basin, China). In this study, the authors evaluated the downscaled phase 5 of the Coupled Model Intercomparison Project (CMIP5) models’ simulations, coupled with the VIC model (CMIP5–VIC) in reproducing flash droughts in a humid subtropical basin in China. Most downscaled CMIP5–VIC simulations can reproduce the spatial patterns of flash droughts with respect to the benchmarks. The coupled models fail to readily replicate interannual variation (interannual pentad change), but most models can reflect the interannual variability (temporal standard deviation) and long-term average pentads of flash droughts. It is difficult to simultaneously depict both the spatial and temporal features of flash droughts within only one coupled model. The climatological patterns of the best multimodel ensemble mean are close to those of the all-model ensemble mean, but the best multimodel ensemble mean has a minimal bias range and relatively low computational burden.
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Mo, Kingtse C., i Dennis P. Lettenmaier. "Prediction of Flash Droughts over the United States". Journal of Hydrometeorology 21, nr 8 (1.08.2020): 1793–810. http://dx.doi.org/10.1175/jhm-d-19-0221.1.
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AbstractWe examine reforecasts of flash droughts over the United States for the late spring (April–May), midsummer (June–July), and late summer/early autumn (August–September) with lead times up to 3 pentads based on the NOAA second-generation Global Ensemble Forecast System reforecasts version 2 (GEFSv2). We consider forecasts of both heat wave and precipitation deficit (P deficit) flash droughts, where heat wave flash droughts are characterized by high temperature and depletion of soil moisture and P deficit flash droughts are caused by lack of precipitation that leads to (rather than being the cause of) high temperature. We find that the GEFSv2 reforecasts generally capture the frequency of occurrence (FOC) patterns. The equitable threat score (ETS) of heat wave flash drought forecasts for late spring in the regions where heat wave flash droughts are most likely to occur over the north-central and Pacific Northwest regions is statistically significant up to 2 pentads. The GEFSv2 reforecasts capture the basic pattern of the FOC of P-deficit flash droughts and also are skillful up to lead about 2 pentads. However, the reforecasts overestimate the P-deficit flash drought FOC over parts of the Southwest in late spring, leading to large false alarm rates. For autumn, the reforecasts underestimate P-deficit flash drought occurrence over California and Nevada. The GEFSv2 reforecasts are able to capture the approximately linear relationship between evaporation and soil moisture, but the lack of skill in precipitation forecasts limits the skill of P-deficit flash drought forecasts.
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Liu, Yi, Ye Zhu, Liliang Ren, Jason Otkin, Eric D. Hunt, Xiaoli Yang, Fei Yuan i Shanhu Jiang. "Two Different Methods for Flash Drought Identification: Comparison of Their Strengths and Limitations". Journal of Hydrometeorology 21, nr 4 (kwiecień 2020): 691–704. http://dx.doi.org/10.1175/jhm-d-19-0088.1.
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AbstractFlash droughts are extreme phenomena that have been identified using two different approaches. The first approach identifies these events based on unusually rapid intensification rates, whereas the second approach implicitly identifies short-term features. This latter approach classifies flash droughts into two types, namely, precipitation deficit and heat wave flash droughts (denoted as PDFD and HWFD). In this study, we evaluate these two approaches over the Yellow River basin (YRB) to determine which approach provides more accurate information about flash droughts and why. Based on the concept of intensification rate, a new quantitative flash drought identification method focused on soil moisture depletion during the onset–development phase is proposed. Its performance was evaluated by comparing the onset time and spatial dynamics of the identified flash droughts with PDFD and HWFD events identified using the second approach. The results show that the rapid-intensification approach is better able to capture the continuous evolution of a flash drought. Since the approach for identifying PDFD and HWFD events does not consider changes in soil moisture with time, it cannot ensure that the events exhibit rapid intensification, nor can it effectively capture flash droughts’ onset. Evaluation of the results showed that the chosen hydrometeorological variables and corresponding thresholds, particularly that of temperature, are the main reasons for the poor performance of the PDFD and HWFD identification approach. This study promotes a deeper understanding of flash droughts that is beneficial for drought monitoring, early warning, and mitigation.
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Otkin, Jason A., Mark Svoboda, Eric D. Hunt, Trent W. Ford, Martha C. Anderson, Christopher Hain i Jeffrey B. Basara. "Flash Droughts: A Review and Assessment of the Challenges Imposed by Rapid-Onset Droughts in the United States". Bulletin of the American Meteorological Society 99, nr 5 (maj 2018): 911–19. http://dx.doi.org/10.1175/bams-d-17-0149.1.
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AbstractGiven the increasing use of the term “flash drought” by the media and scientific community, it is prudent to develop a consistent definition that can be used to identify these events and to understand their salient characteristics. It is generally accepted that flash droughts occur more often during the summer owing to increased evaporative demand; however, two distinct approaches have been used to identify them. The first approach focuses on their rate of intensification, whereas the second approach implicitly focuses on their duration. These conflicting notions for what constitutes a flash drought (i.e., unusually fast intensification vs short duration) introduce ambiguity that affects our ability to detect their onset, monitor their development, and understand the mechanisms that control their evolution. Here, we propose that the definition for “flash drought” should explicitly focus on its rate of intensification rather than its duration, with droughts that develop much more rapidly than normal identified as flash droughts. There are two primary reasons for favoring the intensification approach over the duration approach. First, longevity and impact are fundamental characteristics of drought. Thus, short-term events lasting only a few days and having minimal impacts are inconsistent with the general understanding of drought and therefore should not be considered flash droughts. Second, by focusing on their rapid rate of intensification, the proposed “flash drought” definition highlights the unique challenges faced by vulnerable stakeholders who have less time to prepare for its adverse effects.
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Liang, Miaoling, Xing Yuan, Shiyu Zhou i Zhanshan Ma. "Spatiotemporal Evolution and Nowcasting of the 2022 Yangtze River Mega-Flash Drought". Water 15, nr 15 (29.07.2023): 2744. http://dx.doi.org/10.3390/w15152744.
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Flash droughts challenge early warnings due to their rapid onset, which requires a proper drought index and skillful nowcasting system. A few studies have assessed the nowcast skill for flash droughts using a one-dimensional index, but whether the models can capture their spatiotemporal evolution remains unclear. In this study, a three-dimensional meteorological flash drought index based on the percentile of 15-day moving average precipitation minus evapotranspiration (P-ET) is developed. The index is then used to investigate the spatiotemporal evolution of a mega-flash drought that occurred in the Yangtze River basin during the summer of 2022. The results show that the mega-flash drought started at the beginning of July in the upper reaches of the river and expanded to the middle and lower reaches at the beginning of August due to the spread of the high-pressure system. The evolution is well captured by the proposed three-dimensional index. The spatial correlations between the China Meteorological Administration global medium-range ensemble forecast system (CMA-GFS)’s nowcast and reanalysis ranged from 0.58 to 0.85, and the hit rate and equitable threat score are 0.54 and 0.26, respectively. This study shows that the CMA-GFS nowcast of the P-ET index roughly captured the drought’s evolution, which can be used for flash drought early warnings and water resource management.
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Zhang, Miao, i Xing Yuan. "Rapid reduction in ecosystem productivity caused by flash droughts based on decade-long FLUXNET observations". Hydrology and Earth System Sciences 24, nr 11 (24.11.2020): 5579–93. http://dx.doi.org/10.5194/hess-24-5579-2020.
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Abstract. A flash drought is characterized by its rapid onset and arouses widespread concerns due to its devastating impacts on the environment and society without sufficient early warnings. The increasing frequency of soil moisture flash droughts in a warming climate highlights the importance of understanding its impact on terrestrial ecosystems. Previous studies investigated the vegetation dynamics during several extreme cases of flash drought, but there is no quantitative assessment on how fast the carbon fluxes respond to flash droughts based on decade-long records with different climates and vegetation conditions. Here we identify soil moisture flash drought events by considering decline rate of soil moisture and the drought persistency, and we detect the response of ecosystem carbon and water fluxes to a soil moisture flash drought during its onset and recovery stages based on observations at 29 FLUXNET stations from croplands to forests. Corresponding to the sharp decline in soil moisture and higher vapor pressure deficit (VPD), gross primary productivity (GPP) drops below its normal conditions in the first 16 d and decreases to its minimum within 24 d for more than 50 % of the 151 identified flash drought events, and savannas show highest sensitivity to flash drought. Water use efficiency increases for forests but decreases for cropland and savanna during the recovery stage of flash droughts. These results demonstrate the rapid responses of vegetation productivity and resistance of forest ecosystems to flash drought.
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Li, Yuxin, Sisi Chen, Jun Yin i Xing Yuan. "Technical note: A stochastic framework for identification and evaluation of flash drought". Hydrology and Earth System Sciences 27, nr 5 (14.03.2023): 1077–87. http://dx.doi.org/10.5194/hess-27-1077-2023.
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Abstract. The rapid development of droughts, referred to as flash droughts, can pose serious impacts on agriculture, the ecosystem, human health, and society. However, its definition, using pentad-averaged soil moisture, could result in low accuracy in assessing the drought occurrence, making it difficult to analyze various factors controlling the formation of flash droughts. Here we used a stochastic water balance framework to quantify the whole probability structure of the timing for soil moisture dropping from a higher level to a lower one. Based on this framework, we can theoretically examine the nonlinear relationship between the rapid decline rate of soil moisture and various hydrometeorological factors and identify possible flash drought risks caused by less rainfall (e.g., long dry spells), higher evapotranspiration (e.g., extreme heat waves), lower soil water storage capacity (e.g., deforestation), or a combination thereof. Applying this framework to the global datasets, we obtained global maps of the average time for drought development and the risks of flash drought. We found that possible flash drought development in humid regions, such as southern China and the northeastern United States, calls particular attention to the need for flash drought monitoring and mitigation.
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Osman, Mahmoud, Benjamin F. Zaitchik, Hamada S. Badr, Jordan I. Christian, Tsegaye Tadesse, Jason A. Otkin i Martha C. Anderson. "Flash drought onset over the contiguous United States: sensitivity of inventories and trends to quantitative definitions". Hydrology and Earth System Sciences 25, nr 2 (8.02.2021): 565–81. http://dx.doi.org/10.5194/hess-25-565-2021.
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Abstract. The term “flash drought” is frequently invoked to describe droughts that develop rapidly over a relatively short timescale. Despite extensive and growing research on flash drought processes, predictability, and trends, there is still no standard quantitative definition that encompasses all flash drought characteristics and pathways. Instead, diverse definitions have been proposed, supporting wide-ranging studies of flash drought but creating the potential for confusion as to what the term means and how to characterize it. Use of different definitions might also lead to different conclusions regarding flash drought frequency, predictability, and trends under climate change. In this study, we compared five previously published definitions, a newly proposed definition, and an operational satellite-based drought monitoring product to clarify conceptual differences and to investigate the sensitivity of flash drought inventories and trends to the choice of definition. Our analyses indicate that the newly introduced Soil Moisture Volatility Index definition effectively captures flash drought onset in both humid and semi-arid regions. Analyses also showed that estimates of flash drought frequency, spatial distribution, and seasonality vary across the contiguous United States depending upon which definition is used. Definitions differ in their representation of some of the largest and most widely studied flash droughts of recent years. Trend analysis indicates that definitions that include air temperature show significant increases in flash droughts over the past 40 years, but few trends are evident for definitions based on other surface conditions or fluxes. These results indicate that “flash drought” is a composite term that includes several types of events and that clarity in definition is critical when monitoring, forecasting, or projecting the drought phenomenon.
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Wen, Jinhua, Yian Hua, Chenkai Cai, Shiwu Wang, Helong Wang, Xinyan Zhou, Jian Huang i Jianqun Wang. "Probabilistic Forecast and Risk Assessment of Flash Droughts Based on Numeric Weather Forecast: A Case Study in Zhejiang, China". Sustainability 15, nr 4 (20.02.2023): 3865. http://dx.doi.org/10.3390/su15043865.
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In recent years, flash droughts with a rapid onset and strong intensity have attracted extensive attention due to their impact on agriculture and ecosystems. However, there is still no feasible method for flash drought forecasting and early warning. This paper employs the thresholds of several meteorological variables to identify flash droughts in Zhejiang Province, China, and build a probabilistic flash drought forecasting model through numeric weather forecast (NWF) and the generalized Bayesian model (GBM). The results show that the northern part of Zhejiang Province has the highest risk of flash drought. The NWF is a viable method to provide future information for flash drought forecasting and early warning, but its forecasting accuracy tends to decline with the increase in the lead time and is very limited when the lead time is over 5 days, especially for the precipitation forecast. Due to the low performance of the NWF, the flash drought forecast based on the raw NWF may be unreliable when the lead time is over 5 days. To solve this problem, probabilistic forecasting based on GBM is employed to quantify the uncertainty in the NWF and is tested through an example analysis. In the example analysis, it was found that the probability of a flash drought exceeds 30% from the probabilistic forecasting when the lead time is 12 days, while the deterministic forecasting via the raw NWF cannot identify a flash drought when the lead time is over 5 days. In conclusion, probabilistic forecasting can identify a potential flash drought earlier and can be used to evaluate the risk of a flash drought, which is conducive for the early warning of flash droughts and the development of response measures.
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Yuan, Xing, Yumiao Wang, Peng Ji, Peili Wu, Justin Sheffield i Jason A. Otkin. "A global transition to flash droughts under climate change". Science 380, nr 6641 (14.04.2023): 187–91. http://dx.doi.org/10.1126/science.abn6301.
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Flash droughts have occurred frequently worldwide, with a rapid onset that challenges drought monitoring and forecasting capabilities. However, there is no consensus on whether flash droughts have become the new normal because slow droughts may also increase. In this study, we show that drought intensification rates have sped up over subseasonal time scales and that there has been a transition toward more flash droughts over 74% of the global regions identified by the Intergovernmental Panel on Climate Change Special Report on Extreme Events during the past 64 years. The transition is associated with amplified anomalies of evapotranspiration and precipitation deficit caused by anthropogenic climate change. In the future, the transition is projected to expand to most land areas, with larger increases under higher-emission scenarios. These findings underscore the urgency for adapting to faster-onset droughts in a warmer future.
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Noguera, Iván, Fernando Domínguez-Castro i Sergio M. Vicente-Serrano. "Flash Drought Response to Precipitation and Atmospheric Evaporative Demand in Spain". Atmosphere 12, nr 2 (27.01.2021): 165. http://dx.doi.org/10.3390/atmos12020165.
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Flash drought is the result of strong precipitation deficits and/or anomalous increases in atmospheric evaporative demand (AED), which triggers a rapid decline in soil moisture and stresses vegetation over short periods of time. However, little is known about the role of precipitation and AED in the development of flash droughts. For this paper, we compared the standardized precipitation index (SPI) based on precipitation, the evaporative demand drought index (EDDI) based on AED, and the standardized evaporation precipitation index (SPEI) based on the differences between precipitation and AED as flash drought indicators for mainland Spain and the Balearic Islands for 1961–2018. The results show large differences in the spatial and temporal patterns of flash droughts between indices. In general, there was a high degree of consistency between the flash drought patterns identified by the SPI and SPEI, with the exception of southern Spain in the summer. The EDDI showed notable spatial and temporal differences from the SPI in winter and summer, while it exhibited great coherence with the SPEI in summer. We also examined the sensitivity of the SPEI to AED in each month of the year to explain its contribution to the possible development of flash droughts. Our findings showed that precipitation is the main driver of flash droughts in Spain, although AED can play a key role in the development of these during periods of low precipitation, especially in the driest areas and in summer.
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Han, Jiaqi, Jiahua Zhang, Shanshan Yang i Ayalkibet M. Seka. "Improved Understanding of Flash Drought from a Comparative Analysis of Drought with Different Intensification Rates". Remote Sensing 15, nr 8 (12.04.2023): 2049. http://dx.doi.org/10.3390/rs15082049.
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The rapid intensification of drought, commonly known as flash drought, has recently drawn widespread attention from researchers. However, how the characteristics and drivers, as well as the ecological impacts of rapidly intensified droughts, differ from those of slowly intensified ones still remains unclear over the globe. To this end, we defined three types of droughts based on the root zone soil moisture (RZSM) decline rates, flash droughts, general droughts, and creep droughts, and then implemented a comparative analysis between them across the globe and the 26 Intergovernmental Panel on Climate Change Special Report on Extremes (IPCC-SREX) regions. The ensemble of RZSM from multiple reanalysis datasets was used to reduce the uncertainties. According to the frequency analysis, our findings suggest that flash droughts contributed to the majority of drought events during 1980–2019, indicating the prevalence of rapid transition from an energy-limited to a water-limited condition in most of the regions. The comparative results of vegetation responses show that flash droughts are more likely to happen in the growing season, leading to faster but relatively minor vegetation deterioration compared to the slowly intensified ones. By analyzing the precipitation and temperature anomalies in the month of drought onset, we found the role of temperature (precipitation) on drought intensification can be generalized as the warmer (drier) the climate is or the faster the drought intensifies, but the main driving forces vary by region. Unlike temperature dominating in midwestern Eurasia and northern high latitudes, precipitation plays a prominent role in the monsoon regions. However, the temperature is expected to be the decisive driver in the warming future, given its monotonically increased contribution over the past four decades.
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DeAngelis, Anthony M., Hailan Wang, Randal D. Koster, Siegfried D. Schubert, Yehui Chang i Jelena Marshak. "Prediction Skill of the 2012 U.S. Great Plains Flash Drought in Subseasonal Experiment (SubX) Models". Journal of Climate 33, nr 14 (15.07.2020): 6229–53. http://dx.doi.org/10.1175/jcli-d-19-0863.1.
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AbstractRapid-onset droughts, known as flash droughts, can have devastating impacts on agriculture, water resources, and ecosystems. The ability to predict flash droughts in advance would greatly enhance our preparation for them and potentially mitigate their impacts. Here, we investigate the prediction skill of the extreme 2012 flash drought over the U.S. Great Plains at subseasonal lead times (3 weeks or more in advance) in global forecast systems participating in the Subseasonal Experiment (SubX). An additional comprehensive set of subseasonal hindcasts with NASA’s GEOS model, a SubX model with relatively high prediction skill, was performed to investigate the separate contributions of atmospheric and land initial conditions to flash drought prediction skill. The results show that the prediction skill of the SubX models is quite variable. While skillful predictions are restricted to within the first two forecast weeks in most models, skill is considerably better (3–4 weeks or more) for certain models and initialization dates. The enhanced prediction skill is found to originate from two robust sources: 1) accurate soil moisture initialization once dry soil conditions are established, and 2) the satisfactory representation of quasi-stationary cross-Pacific Rossby wave trains that lead to the rapid intensification of flash droughts. Evidence is provided that the importance of soil moisture initialization applies more generally to central U.S. summer flash droughts. Our results corroborate earlier findings that accurate soil moisture initialization is important for skillful subseasonal forecasts and highlight the need for additional research on the sources and predictability of drought-inducing quasi-stationary atmospheric circulation anomalies.
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Koster, R. D., S. D. Schubert, H. Wang, S. P. Mahanama i Anthony M. DeAngelis. "Flash Drought as Captured by Reanalysis Data: Disentangling the Contributions of Precipitation Deficit and Excess Evapotranspiration". Journal of Hydrometeorology 20, nr 6 (1.06.2019): 1241–58. http://dx.doi.org/10.1175/jhm-d-18-0242.1.
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Abstract Flash droughts—uncharacteristically rapid dryings of the land system—are naturally associated with extreme precipitation deficits. Such precipitation deficits, however, do not tell the whole story, for land surface drying can be exacerbated by anomalously high evapotranspiration (ET) rates driven by anomalously high temperatures (e.g., during heat waves), anomalously high incoming radiation (e.g., from reduced cloudiness), and other meteorological anomalies. In this study, the relative contributions of precipitation and ET anomalies to flash drought generation in the Northern Hemisphere are quantified through the analysis of diagnostic fields contained within the MERRA-2 reanalysis product. Unique to the approach is the explicit treatment of soil moisture impacts on ET through relationships diagnosed from the reanalysis data; under this treatment, an ET anomaly that is negative relative to the local long-term climatological mean is still considered positive in terms of its contribution to a flash drought if it is high for the concurrent value of soil moisture. Maps produced in the analysis show the fraction of flash drought production stemming specifically from ET anomalies and illustrate how ET anomalies for some droughts are related to temperature and radiation anomalies. While ET is found to have an important impact on flash drought production in the central United States and in parts of Russia known from past studies to be prone to heat wave–related drought, and while this impact does appear stronger during the onset (first several days) of flash droughts, overall the contribution of ET to these droughts is small relative to the contribution of precipitation deficit.
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Otkin, Jason A., Yafang Zhong, Eric D. Hunt, Jordan I. Christian, Jeffrey B. Basara, Hanh Nguyen, Matthew C. Wheeler i in. "Development of a Flash Drought Intensity Index". Atmosphere 12, nr 6 (9.06.2021): 741. http://dx.doi.org/10.3390/atmos12060741.
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Flash droughts are characterized by a period of rapid intensification over sub-seasonal time scales that culminates in the rapid emergence of new or worsening drought impacts. This study presents a new flash drought intensity index (FDII) that accounts for both the unusually rapid rate of drought intensification and its resultant severity. The FDII framework advances our ability to characterize flash drought because it provides a more complete measure of flash drought intensity than existing classification methods that only consider the rate of intensification. The FDII is computed using two terms measuring the maximum rate of intensification (FD_INT) and average drought severity (DRO_SEV). A climatological analysis using soil moisture data from the Noah land surface model from 1979–2017 revealed large regional and interannual variability in the spatial extent and intensity of soil moisture flash drought across the US. Overall, DRO_SEV is slightly larger over the western and central US where droughts tend to last longer and FD_INT is ~75% larger across the eastern US where soil moisture variability is greater. Comparison of the FD_INT and DRO_SEV terms showed that they are strongly correlated (r = 0.82 to 0.90) at regional scales, which indicates that the subsequent drought severity is closely related to the magnitude of the rapid intensification preceding it. Analysis of the 2012 US flash drought showed that the FDII depiction of severe drought conditions aligned more closely with regions containing poor crop conditions and large yield losses than that captured by the intensification rate component (FD_INT) alone.
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Chen, Liang, Trent W. Ford i Priyanka Yadav. "The Role of Vegetation in Flash Drought Occurrence: A Sensitivity Study Using Community Earth System Model, Version 2". Journal of Hydrometeorology 22, nr 4 (kwiecień 2021): 845–57. http://dx.doi.org/10.1175/jhm-d-20-0214.1.
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AbstractFlash droughts are noted by their unusually rapid rate of onset or intensification, which makes it difficult to anticipate and prepare for them, thus resulting in severe impacts. Although the development of flash drought can be associated with certain atmospheric conditions, vegetation also plays a role in propagating flash drought. This study examines the climatology of warm season (March–September) flash drought occurrence in the United States between 1979 and 2014, and quantifies the possible impacts of vegetation on flash drought based on a set of sensitivity experiments using the Community Earth System Model, version 2 (CESM2). With atmospheric nudging, CESM2 well captures historical flash drought. Compared with NASA’s Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2), and National Climate Assessment–Land Data Assimilation System (NCA-LDAS), CESM2 shows agreement on the high flash drought frequency in the Great Plains and southeastern United States, but overestimates flash drought occurrence in the Midwest. The vegetation sensitivity experiments suggest that vegetation greening can significantly increase the flash drought frequency in the Great Plains and the western United States during the warm seasons through enhanced evapotranspiration. However, flash drought occurrence is not significantly affected by vegetation phenology in the eastern United States and Midwest due to weak land–atmosphere coupling. In response to vegetation greening, the extent of flash drought also increases, but the duration of flash drought is not sensitive to greening. This study highlights the importance of vegetation in flash drought development, and provides insights for improving flash drought monitoring and early warning.
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Zhang, Minxia, Shulin Chen, Hong Jiang, Yong Lin, Jinmeng Zhang, Xinzhang Song i Guomo Zhou. "Water-Use Characteristics and Physiological Response of Moso Bamboo to Flash Droughts". International Journal of Environmental Research and Public Health 16, nr 12 (19.06.2019): 2174. http://dx.doi.org/10.3390/ijerph16122174.
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Frequent flash droughts can rapidly lead to water shortage, which affects the stability of ecosystems. This study determines the water-use characteristics and physiological mechanisms underlying Moso bamboo response to flash-drought events, and estimates changes to water budgets caused by extreme drought. We analyzed the variability in forest canopy transpiration versus precipitation from 2011–2013. Evapotranspiration reached 730 mm during flash drought years. When the vapor pressure deficit > 2 kPa and evapotranspiration > 4.27 mm·day−1, evapotranspiration was mainly controlled through stomatal opening and closing to reduce water loss. However, water exchange mainly occurred in the upper 0–50 cm of the soil. When soil volumetric water content of 50 cm was lower than 0.17 m3·m−3, physiological dehydration occurred in Moso bamboo to reduce transpiration by defoliation, which leads to water-use efficiency decrease. When mean stand density was <3500 trees·ha−1, the bamboo forest can safely survive the flash drought. Therefore, we recommend thinning Moso bamboo as a management strategy to reduce transpiration in response to future extreme drought events. Additionally, the response function of soil volumetric water content should be used to better simulate evapotranspiration, especially when soil water is limited.
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Mo, Kingtse C., i Dennis P. Lettenmaier. "Heat wave flash droughts in decline". Geophysical Research Letters 42, nr 8 (24.04.2015): 2823–29. http://dx.doi.org/10.1002/2015gl064018.
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Walker, David W., i Anne F. Van Loon. "Droughts are coming on faster". Science 380, nr 6641 (14.04.2023): 130–32. http://dx.doi.org/10.1126/science.adh3097.
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Hobbins, Michael T., Andrew Wood, Daniel J. McEvoy, Justin L. Huntington, Charles Morton, Martha Anderson i Christopher Hain. "The Evaporative Demand Drought Index. Part I: Linking Drought Evolution to Variations in Evaporative Demand". Journal of Hydrometeorology 17, nr 6 (1.06.2016): 1745–61. http://dx.doi.org/10.1175/jhm-d-15-0121.1.
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Abstract Many operational drought indices focus primarily on precipitation and temperature when depicting hydroclimatic anomalies, and this perspective can be augmented by analyses and products that reflect the evaporative dynamics of drought. The linkage between atmospheric evaporative demand E0 and actual evapotranspiration (ET) is leveraged in a new drought index based solely on E0—the Evaporative Demand Drought Index (EDDI). EDDI measures the signal of drought through the response of E0 to surface drying anomalies that result from two distinct land surface–atmosphere interactions: 1) a complementary relationship between E0 and ET that develops under moisture limitations at the land surface, leading to ET declining and increasing E0, as in sustained droughts, and 2) parallel ET and E0 increases arising from increased energy availability that lead to surface moisture limitations, as in flash droughts. To calculate EDDI from E0, a long-term, daily reanalysis of reference ET estimated from the American Society of Civil Engineers (ASCE) standardized reference ET equation using radiation and meteorological variables from the North American Land Data Assimilation System phase 2 (NLDAS-2) is used. EDDI is obtained by deriving empirical probabilities of aggregated E0 depths relative to their climatologic means across a user-specific time period and normalizing these probabilities. Positive EDDI values then indicate drier-than-normal conditions and the potential for drought. EDDI is a physically based, multiscalar drought index that that can serve as an indicator of both flash and sustained droughts, in some hydroclimates offering early warning relative to current operational drought indices. The performance of EDDI is assessed against other commonly used drought metrics across CONUS in Part II.
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Basara, Jeffrey, i Jordan Christian. "Farming and the Risk of Flash Droughts". American Scientist 111, nr 4 (2023): 238. http://dx.doi.org/10.1511/2023.111.4.238.
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Park, Seonyoung, Eunkyo Seo, Daehyun Kang, Jungho Im i Myong-In Lee. "Prediction of Drought on Pentad Scale Using Remote Sensing Data and MJO Index through Random Forest over East Asia". Remote Sensing 10, nr 11 (15.11.2018): 1811. http://dx.doi.org/10.3390/rs10111811.
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Rapidly developing droughts, including flash droughts, have frequently occurred throughout East Asia in recent years, causing significant damage to agricultural ecosystems. Although many drought monitoring and warning systems have been developed in recent decades, the short-term prediction of droughts (within 10 days) is still challenging. This study has developed drought prediction models for a short-period of time (one pentad) using remote-sensing data and climate variability indices over East Asia (20°–50°N, 90°–150°E) through random forest machine learning. Satellite-based drought indices were calculated using the European Space Agency (ESA) Climate Change Initiative (CCI) soil moisture, Tropical Rainfall Measuring Mission (TRMM) precipitation, Moderate Resolution Imaging Spectroradiometer (MODIS) land surface temperature (LST), and normalized difference vegetation index (NDVI). The real-time multivariate (RMM) Madden–Julian oscillation (MJO) indices were used because the MJO is a short timescale climate variability and has important implications for droughts in East Asia. The validation results show that those drought prediction models with the MJO variables (r ~ 0.7 on average) outperformed the original models without the MJO variables (r ~ 0.4 on average). The predicted drought index maps showed similar spatial distribution to actual drought index maps. In particular, the MJO-based models captured sudden changes in drought conditions well, from normal/wet to dry or dry to normal/wet. Since the developed models can produce drought prediction maps at high resolution (5 km) for a very short timescale (one pentad), they are expected to provide decision makers with more accurate information on rapidly changing drought conditions.
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Gerken, Tobias, Gabriel T. Bromley, Benjamin L. Ruddell, Skylar Williams i Paul C. Stoy. "Convective suppression before and during the United States Northern Great Plains flash drought of 2017". Hydrology and Earth System Sciences 22, nr 8 (7.08.2018): 4155–63. http://dx.doi.org/10.5194/hess-22-4155-2018.
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Abstract. Flash droughts tend to be disproportionately destructive because they intensify rapidly and are difficult to prepare for. We demonstrate that the 2017 US Northern Great Plains (NGP) flash drought was preceded by a breakdown of land–atmosphere coupling. Severe drought conditions in the NGP were first identified by drought monitors in late May 2017 and rapidly progressed to exceptional drought in July. The likelihood of convective precipitation in May 2017 in northeastern Montana, however, resembled that of a typical August when rain is unlikely. Based on the lower tropospheric humidity index (HIlow), convective rain was suppressed by the atmosphere on nearly 50 % of days during March in NE Montana and central North Dakota, compared to 30 % during a normal year. Micrometeorological variables, including potential evapotranspiration (ETp), were neither anomalously high nor low before the onset of drought. Incorporating convective likelihood to drought forecasts would have noted that convective precipitation in the NGP was anomalously unlikely during the early growing season of 2017. It may therefore be useful to do so in regions that rely on convective precipitation.
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Poonia, Vikas, Manish Kumar Goyal, Srinidhi Jha i Saket Dubey. "Terrestrial ecosystem response to flash droughts over India". Journal of Hydrology 605 (luty 2022): 127402. http://dx.doi.org/10.1016/j.jhydrol.2021.127402.
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Mahto, Shanti Shwarup, i Vimal Mishra. "Dominance of summer monsoon flash droughts in India". Environmental Research Letters 15, nr 10 (6.10.2020): 104061. http://dx.doi.org/10.1088/1748-9326/abaf1d.
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van Ginkel, Maarten, i Chandrashekhar Biradar. "Drought Early Warning in Agri-Food Systems". Climate 9, nr 9 (26.08.2021): 134. http://dx.doi.org/10.3390/cli9090134.
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Droughts will increase in frequency, intensity, duration, and spread under climate change. Drought affects numerous sectors in society and the natural environment, including short-term reduced crop production, social conflict over water allocation, severe outmigration, and eventual famine. Early action can prevent escalation of impacts, requiring drought early warning systems (DEWSs) that give current assessments and sufficient notice for active risk management. While most droughts are relatively slow in onset, often resulting in late responses, flash droughts are becoming more frequent, and their sudden onset poses challenging demands on DEWSs for timely communication. We examine several DEWSs at global, regional, and national scales, with a special emphasis on agri-food systems. Many of these have been successful, such as some of the responses to 2015–2017 droughts in Africa and Latin America. Successful examples show that early involvement of stakeholders, from DEWS development to implementation, is crucial. In addition, regional and global cooperation can cross-fertilize with new ideas, reduce reaction time, and raise efficiency. Broadening partnerships also includes recruiting citizen science and including seemingly subjective indigenous knowledge that can improve monitoring, data collection, and uptake of response measures. More precise and more useful DEWSs in agri-food systems will prove even more cost-effective in averting the need for emergency responses, improving global food security.
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Limones, Natalia. "A global-scale overview of precipitation-deficit flash droughts". Terrestrial, Atmospheric and Oceanic Sciences 32, nr 4 (2021): 597. http://dx.doi.org/10.3319/tao.2021.09.16.01.
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Christian, Jordan I., Jeffrey B. Basara, Jason A. Otkin i Eric D. Hunt. "Regional characteristics of flash droughts across the United States". Environmental Research Communications 1, nr 12 (4.11.2019): 125004. http://dx.doi.org/10.1088/2515-7620/ab50ca.
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Tejakusuma, I. G., E. H. Sittadewi i R. Fitriani. "Hydrometeorological hazard detection and warning for risk reduction in West Java, Indonesia". IOP Conference Series: Earth and Environmental Science 1192, nr 1 (1.06.2023): 012043. http://dx.doi.org/10.1088/1755-1315/1192/1/012043.
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Abstract Climate-related disasters, including hydrometeorological disasters, have increased over the last decade, accounting for more than 90% of all-natural disasters in Indonesia. To reduce the risk of disaster, the hydrometeorological disaster must be mitigated. The research, carried out at Sukakerti and Tugumukti villages in West Java, aimed at assessing flash flood disaster conditions and designing hydrometeorological disaster early warning instrumentation for community preparedness. Sukakerti Village has a V-shaped river valley and winding primary and secondary forest morphology. Rainfall-caused landslides precede flash floods. Tugumukti village is characterized by undulating hills and is situated directly on a small river flowing from Mount Burangrang. The river that caused the flash flood is only a few tens of meters wide, but settlements have sprung up all around it. Drought affects agricultural activities during the dry season. Hydrometeorological early warning instrumentation for landslides, flash floods, and agricultural droughts comprises radio communication between field devices and routers and a remote data center. Humidity, temperature, solar radiation, wind speed and direction, rainfall, soil moisture, slope, and ground vibration are all sensors. A speaker on the router warns the public of a potential disaster. This technology outperforms GSM and satellite communications in terms of cost, operation, and maintenance.
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Hoell, Andrew, Britt-Anne Parker, Michael Downey, Natalie Umphlett, Kelsey Jencso, F. Adnan Akyuz, Dannele Peck i in. "Lessons Learned from the 2017 Flash Drought across the U.S. Northern Great Plains and Canadian Prairies". Bulletin of the American Meteorological Society 101, nr 12 (grudzień 2020): E2171—E2185. http://dx.doi.org/10.1175/bams-d-19-0272.1.
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AbstractThe 2017 flash drought arrived without early warning and devastated the U.S. northern Great Plains region comprising Montana, North Dakota, and South Dakota and the adjacent Canadian Prairies. The drought led to agricultural production losses exceeding $2.6 billion in the United States, widespread wildfires, poor air quality, damaged ecosystems, and degraded mental health. These effects motivated a multiagency collaboration among academic, tribal, state, and federal partners to evaluate drought early warning systems, coordination efforts, communication, and management practices with the goal of improving resilience and response to future droughts. This essay provides an overview on the causes, predictability, and historical context of the drought, the impacts of the drought, opportunities for drought early warning, and an inventory of lessons learned. Key lessons learned include the following: 1) building partnerships during nondrought periods helps ensure that proper relationships are in place for a coordinated and effective drought response; 2) drought information providers must improve their understanding of the annual decision cycles of all relevant sectors, including, and beyond, direct impacts in agricultural sectors; and 3) ongoing monitoring of environmental conditions is vital to drought early warning, given that seasonal forecasts lack skill over the northern Great Plains.
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Noguera, Iván, Fernando Domínguez‐Castro i Sergio M. Vicente‐Serrano. "Characteristics and trends of flash droughts in Spain, 1961–2018". Annals of the New York Academy of Sciences 1472, nr 1 (14.05.2020): 155–72. http://dx.doi.org/10.1111/nyas.14365.
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Jong, Bor-Ting, Matthew Newman i Andrew Hoell. "Subseasonal Meteorological Drought Development over the Central United States during Spring". Journal of Climate 35, nr 8 (15.04.2022): 2525–47. http://dx.doi.org/10.1175/jcli-d-21-0435.1.
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Abstract Diagnosis of rapidly developing springtime droughts in the central United States has mostly been made via numerous individual case studies rather than in an aggregate sense. This study investigates common aspects of subseasonal “meteorological drought” evolution, here defined as persistent precipitation minus evapotranspiration (P − ET) deficits, revealed in early (1 April–15 May) and late (16 May–30 June) spring composites of 5-day running mean JRA-55 reanalysis data for three different central U.S. regions during 1958–2018. On average, these droughts are initiated by a quasi-stationary Rossby wave packet (RWP), propagating from the western North Pacific, which arises about a week prior to drought onset. The RWP is related to a persistent ridge west of the incipient drought region and strong subsidence over it. This subsidence is associated with low-level divergent flow that dries the atmosphere and suppresses precipitation for roughly 1–2 weeks, and generally has a greater impact on the local moisture budget than does reduced poleward moisture transport. The resulting “dynamically driven” evaporative demand corresponds to a rapid drying of the root-zone soil moisture, which decreases around 40 percentiles within about 10 days. Anomalous near-surface warmth develops only after the P − ET deficit onset, as does anomalously low soil moisture that then lingers a month or more, especially in late spring. The horizontal scale of the RWPs, and of the related drought anomalies, decreases from early to late spring, consistent with the climatological change in the Pacific Rossby waveguide. Finally, while this composite analysis is based upon strong, persistent P − ET deficits, it still appears to capture much of the springtime development of “flash droughts” as well.
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Cui, Wei, Qian Xiong, Yinqi Zheng, Junfu Zhao, Tangzhe Nie, Lan Wu i Zhongyi Sun. "A Study on the Vulnerability of the Gross Primary Production of Rubber Plantations to Regional Short-Term Flash Drought over Hainan Island". Forests 13, nr 6 (8.06.2022): 893. http://dx.doi.org/10.3390/f13060893.
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Rapidly developing droughts, including flash droughts, have occurred frequently in recent years, causing significant damage to agroforestry ecosystems, and they are expected to increase in the future due to global warming. The artificial forest area in China is the largest in the world, and its carbon budget is crucial to the global carbon sink. As the most prominent plantation plant in the tropics, the rubber (Hevea brasiliensis (Willd. ex A. Juss.) Muell. Arg.) ecosystem not only has important economic significance, but also has the potential to be a major natural carbon sink in hot areas. Frequent drought events have a significant impact on rubber ecosystem productivity, yet there have been few reports on the vulnerability of rubber productivity to drought. The objective of this study is to evaluate the vulnerability of rubber ecosystem gross primary production (GPP) to short-term flash drought (STFD) in Hainan Island, utilizing the localized EC-LUE model (eddy covariance–light use efficiency) validated by flux tower observations as the research tool to conduct the scenario simulations which defined by standard relative humidity index (SRHI), in a total of 96 scenarios (timing × intensity). The results show that, in terms of time, the rubber ecosystem in Hainan Island has the highest vulnerability to STFD during the early rainy season and the lowest at the end of the rainy season. From the dry season to the rainy season, the impact of STFD gradually extends to the northeast. Spatially, the vulnerability of the northern island is higher than that of the southern island and that of the western part is higher than that of eastern Hainan Island. With the increase in STFD intensity, the spatial distribution center of the vulnerability of rubber ecosystem GPP in Hainan Island gradually moves southward. The spatiotemporal pattern of the vulnerability of the rubber ecosystem GPP to STFD over Hainan Island plotted by this study is expected to provide decision makers with more accurate information on the prevention and control of drought disaster risk in rubber ecosystems.
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Chinnasamy, Pennan, i Revathi Ganapathy. "Long-term variations in water storage in Peninsular Malaysia". Journal of Hydroinformatics 20, nr 5 (7.11.2017): 1180–90. http://dx.doi.org/10.2166/hydro.2017.043.
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Abstract Information on ongoing climate change impacts on water availability is limited for Asian regions, particularly for Peninsular Malaysia. Annual flash floods are common during peak monsoon seasons, while the dry seasons are hit by droughts, leading to socio-economic stress. This study, for the first time, analyzed the long-term trends (14 years, from 2002 to 2014) in terrestrial water storage and groundwater storage for Peninsular Malaysia, using Gravity Recovery And Climate Experiment data. Results indicate a decline in net terrestrial and groundwater storage over the last decade. Spatially, the northern regions are more affected by droughts, while the southern regions have more flash floods. Groundwater storage trends show strong correlations to the monsoon seasons, indicating that most of the shallow aquifer groundwater is used. Results also indicate that, with proper planning and management, excess monsoon/flash flood water can be stored in water storage structures up to the order of 87 billion liters per year. This can help in dry season water distribution and water transfer projects. Findings from this study can expand the understanding of ongoing climate change impacts on groundwater storage and terrestrial water storage, and can lead to better management of water resources in Peninsular Malaysia.
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Luo, Han, Zhengjiang Ma, Huanping Wu, Yonghua Li, Bei Liu, Yuxia Li i Lei He. "Validation Analysis of Drought Monitoring Based on FY-4 Satellite". Applied Sciences 13, nr 16 (10.08.2023): 9122. http://dx.doi.org/10.3390/app13169122.
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Droughts are natural disasters that have significant implications for agricultural production and human livelihood. Under climate change, the drought process is accelerating, such as the intensification of flash droughts. The efficient and quick monitoring of droughts has increasingly become a crucial measure in responding to extreme drought events. We utilized multi-imagery data from the geostationary meteorological satellite FY-4A within one day; implemented the daily Maximum Value Composite (MVC) method to minimize interference from the clouds, atmosphere, and anomalies; and developed a method for calculating the daily-scale Temperature Vegetation Drought Index (TVDI), which is a dryness index. Three representative drought events (Yunnan Province, Guangdong Province, and the Huanghuai region) from 2021 to 2022 were selected for validation, respectively. We evaluated the spatial and temporal effects of the TVDI with the Soil Relative Humidity Index (SRHI) and the Meteorological Drought Composite Index (MCI). The results show that the TVDI has stronger negative correlations with the MCI and SRHI in moderate and severe drought events. Meanwhile, the TVDI and SRHI exhibited similar trends. The trends of drought areas identified by the TVDI, SRHI, and MCI were consistent, while the drought area identified by the TVDI was slightly higher than the SRHI. Yunnan Province has the most concentrated distribution, which is mostly between 16.93 and 25.22%. The spatial distribution of the TVDI by FY-4A and MODIS is generally consistent, and the differences in severe drought areas may be attributed to disparities in the NDVI. Furthermore, the TVDI based on FY-4A provides a higher number of valid pixels (437 more pixels in the Huanghuai region) than that based on MODIS, yielding better overall drought detection. The spatial distribution of the TVDI between FY-4A and Landsat-8 is also consistent. FY-4A has the advantage of acquiring a complete image on a daily basis, and lower computational cost in regional drought monitoring. The results indicate the effectiveness of the FY-4A TVDI in achieving daily-scale drought monitoring, with a larger number of valid pixels and better spatial consistency with station indices. This study provides a new solution for drought monitoring using a geostationary meteorological satellite from different spatial–temporal perspectives to facilitate comprehensive drought monitoring.
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Gou, Qiqi, Yonghua Zhu, Haishen Lü, Robert Horton, Xiaohan Yu, Haoqiang Zhang, Xiaoyi Wang i in. "Application of an improved spatio-temporal identification method of flash droughts". Journal of Hydrology 604 (styczeń 2022): 127224. http://dx.doi.org/10.1016/j.jhydrol.2021.127224.
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Pendergrass, Angeline G., Gerald A. Meehl, Roger Pulwarty, Mike Hobbins, Andrew Hoell, Amir AghaKouchak, Céline J. W. Bonfils i in. "Flash droughts present a new challenge for subseasonal-to-seasonal prediction". Nature Climate Change 10, nr 3 (marzec 2020): 191–99. http://dx.doi.org/10.1038/s41558-020-0709-0.
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Theilen-Willige, Barbara, i Helmut Wenzel. "Remote Sensing and GIS Contribution to a Natural Hazard Database in Western Saudi Arabia". Geosciences 9, nr 9 (31.08.2019): 380. http://dx.doi.org/10.3390/geosciences9090380.
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The most frequent disasters in Western Saudi Arabia are flash floods, earthquakes and volcanism, especially submarine volcanism potentially causing tsunamis in the Red Sea and submarine mass movements, dust storms and droughts. As the consequences and effects of the climate change are expected to have an increasing impact on the intensity and occurrence of geohazards as flash floods, length of drought periods, or dust storms, the systematic, continuous monitoring of these hazards and affected areas using satellite data and integration of the results into a geographic information systems (GIS) database is an important issue for hazard preparedness and risk assessment. Visual interpretation and digital image processing of optical aerial and satellite images, as well as of radar images, combined with Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), Shuttle Radar Topographic Mission (SRTM) and Advanced Land Observing Satellite (ALOS) PALSAR DEM data are used in this study for the mapping and inventory of areas prone to geohazards, such as flash floods or tsunami flooding. Causal or critical environmental factors influencing the disposition to be affected by hazards can be analyzed interactively in a GIS database. How remote sensing and GIS methods can contribute to the detection and continuously, standardized monitoring of geohazards in Western Saudi Arabia as part of a natural hazard geodatabase is demonstrated by several examples, such as the detection of areas prone to hydrological hazards, such as flash floods causing flooding of roads and settlements, the outlining of coastal areas of the Red Sea prone to tsunami flooding and storm surge, the mapping of traces of recent volcanic activity, and of fault/fracture zones and structural features, especially of ring structures.
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Xi, Xiazhen, i Xing Yuan. "Significant water stress on gross primary productivity during flash droughts with hot conditions". Agricultural and Forest Meteorology 324 (wrzesień 2022): 109100. http://dx.doi.org/10.1016/j.agrformet.2022.109100.
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Liu, Yi, Ye Zhu, Linqi Zhang, Liliang Ren, Fei Yuan, Xiaoli Yang i Shanhu Jiang. "Flash droughts characterization over China: From a perspective of the rapid intensification rate". Science of The Total Environment 704 (luty 2020): 135373. http://dx.doi.org/10.1016/j.scitotenv.2019.135373.
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Li, Jun, Zhaoli Wang, Xushu Wu, Shenglian Guo i Xiaohong Chen. "Flash droughts in the Pearl River Basin, China: Observed characteristics and future changes". Science of The Total Environment 707 (marzec 2020): 136074. http://dx.doi.org/10.1016/j.scitotenv.2019.136074.
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Sanxay Boutsamaly, Chankhachone Sonemanivong, Soulyphan Kannitha, Phoummixay Siharath, Somchay Vilaychaleun, Khampasith Thammathevo, Amphayvanh Oudomdeth i Tavanh Kittiphone. "Spatial analysis of flash flood and Drought impact from Climate Change in Phongsaly District, Phogsaly Province, by using Geo-Informatics Technology and Modelling". Global Sustainability Research 2, nr 3 (22.06.2023): 1–20. http://dx.doi.org/10.56556/gssr.v2i3.515.
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A method for predicting the water resource in the region in the future to be used as a basis for mitigating the consequences is to study how climate change affects hydrology. The purpose of this study is to i). choose a global climate model that is suitable for the area, ii). rainfall run-off modelling, iii). drought and flood hazard index map. The SSP-126, SSP-245, and SSP-585 scenarios were chosen as the most appropriate global climate model among the four institutes, with efficiency criteria using the coefficient of Nash-Sutcliffe and Kling-Gupta and then calibrate the data with the Bias Correction Linear Scaling method which divides the analysis period into 2 periods for Near-Future and Far-Future from analyzing Rainfall Run-off Modeling from Rainfall Concentration 1-hours, 3-hours and 6-hours. It was found that the SSP-585 scenario in the Rainfall Concentration 1-hours model has the most dangerous area for very high risk until the end of the 21st century. For the analysis of drought indices SPI_1, SPI_3 and SPI_6 in Near-Future, it was found that the frequency of droughts is increasing according to the worst scenario, the scenario with the most drought is SSP-585 and in the Far-Future, the frequency of drought is decreasing according to the worst scenario, the scenario with the most drought is SSP-126.
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Lorenz, David J., Jason A. Otkin, Mark Svoboda, Christopher R. Hain, Martha C. Anderson i Yafang Zhong. "Predicting the U.S. Drought Monitor Using Precipitation, Soil Moisture, and Evapotranspiration Anomalies. Part II: Intraseasonal Drought Intensification Forecasts". Journal of Hydrometeorology 18, nr 7 (1.07.2017): 1963–82. http://dx.doi.org/10.1175/jhm-d-16-0067.1.
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Abstract Probabilistic forecasts of U.S. Drought Monitor (USDM) intensification over 2-, 4-, and 8-week time periods are developed based on recent anomalies in precipitation, evapotranspiration, and soil moisture. These statistical forecasts are computed using logistic regression with cross validation. While recent precipitation, evapotranspiration, and soil moisture do provide skillful forecasts, it is found that additional information on the current state of the USDM adds significant skill to the forecasts. The USDM state information takes the form of a metric that quantifies the “distance” from the next-higher drought category using a nondiscrete estimate of the current USDM state. This adds skill because USDM states that are close to the next-higher drought category are more likely to intensify than states that are farther from this threshold. The method shows skill over most of the United States but is most skillful over the north-central United States, where the cross-validated Brier skill score averages 0.20 for both 2- and 4-week forecasts. The 8-week forecasts are less skillful in most locations. The 2- and 4-week probabilities have very good reliability. The 8-week probabilities, on the other hand, are noticeably overconfident. For individual drought events, the method shows the most skill when forecasting high-amplitude flash droughts and when large regions of the United States are experiencing intensifying drought.
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Do Thi, Mui, i Tuan Pham Anh. "Disasters and some measures to respond to disasters in Son La province". Journal of Science Social Science 67, nr 3 (lipiec 2022): 170–78. http://dx.doi.org/10.18173/2354-1067.2022-0050.
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Due to the influence of climate change, Son La province suffers many impacts of natural disasters on the economy in general and the agriculture, forestry, and fishery industry in particular. The main manifestations of natural disasters in Son La are flash floods, pipe floods, droughts, hail, thunderstorms, and hoarfrost. By the method of collecting documents, analyzing, evaluating, and overviewing natural disasters, and assessing the damage caused by natural disasters to agricultural, forestry, and fishery production, thereby proposing a number of measures. response to natural disasters in Son La province.
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Ojima, Dennis S. "Climate resilient management in response to flash droughts in the US Northern Great Plains". Current Opinion in Environmental Sustainability 48 (luty 2021): 125–31. http://dx.doi.org/10.1016/j.cosust.2021.01.002.
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