Flash Drought Characteristics by Different Severities in Humid Subtropical Basins: A Case Study in the Gan River Basin, China

2021 ◽  
pp. 1-44
Author(s):  
Yuqing Zhang ◽  
Qinglong You ◽  
Guangxiong Mao ◽  
Changchun Chen ◽  
Xin Li ◽  
...  
Keyword(s):  
Soil Moisture ◽  
River Basin ◽  
Vapour Pressure Deficit ◽  
Severity Index ◽  
Drought Severity ◽  
Rapid Decline ◽  
Drought Risk ◽  
Drought Event ◽  
Drought Period ◽  
Drought Intensity

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 towards 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, vapour 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 to 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 approximately every 3-6, 5-15, 10-50, and 30-200 year intervals, respectively, based on the copula analysis.

scholarly journals Estimating the water needed to end the drought or reduce the drought severity in the Carpathian region

2015 ◽  
Vol 19 (1) ◽  
pp. 177-193 ◽  
Author(s):  
T. Antofie ◽  
G. Naumann ◽  
J. Spinoni ◽  
J. Vogt
Keyword(s):  
Pannonian Basin ◽  
Quantitative Measure ◽  
Severity Index ◽  
Drought Severity ◽  
Severe Drought ◽  
Drought Event ◽  
Local Conditions ◽  
Drought Period ◽  
Carpathian Region ◽  
Drought Recovery

Abstract. A drought severity climatology for the Carpathian region has been produced using the self-calibrating Palmer Drought Severity Index (Sc-PDSI) for the period 1961–2010. Using the Sc-PDSI and the assumptions of the Palmer drought model (PDM) the precipitation required for drought termination (when Sc-PDSI reaches −0.5) and amelioration (when Sc-PDSI reaches −2.0) are computed for periods of 1, 3, and 6 months. We discuss the reduction of the uncertainty in the determination of the beginning and ending of drought conditions, and provide a quantitative measure of the probability that any drought could be ameliorated or terminated. We present how the spatial variability of the amount of water needed for drought recovery and the climatological probability of receiving that amount of water is determined by the local conditions against the general climate characteristics of a small area such as the Carpathian region. Regionally, the Pannonian Basin, the Transylvanian Plateau and the external Carpathian foothills and plains in the southern and eastern part of the region require the highest quantity of precipitation to recover from a drought while having the lowest climatological probabilities for such amounts of rainfall. High precipitation amounts over the northern and northwest part of the region result in higher soil moisture supplies and higher climatological probabilities to end a given drought event. Moreover, the succession and/or predominance of particular types of general atmospheric circulation patterns produce a seasonal cycle and inter-annual variability of precipitation that is quantitatively reflected in the excess of precipitation that is above normal required for drought recovery. Overall, the results of this study provide an overview on the chances of recovery from a drought period with moderate or severe drought and present information useful in decision making in water and drought management.

scholarly journals Estimating the water needed to end or ameliorate the drought in the Carpathian region

2014 ◽  
Vol 11 (2) ◽  
pp. 1493-1527 ◽  
Author(s):  
T. Antofie ◽  
G. Naumann ◽  
J. Spinoni ◽  
J. Vogt
Keyword(s):  
Pannonian Basin ◽  
Quantitative Measure ◽  
Severity Index ◽  
Drought Severity ◽  
Severe Drought ◽  
Drought Event ◽  
Local Conditions ◽  
Drought Period ◽  
Carpathian Region ◽  
Drought Recovery

Abstract. A drought severity climatology for the Carpathian Region has been produced using the self-calibrating Palmer Drought Severity Index (Sc-PDSI) for the period 1961–2010. Using the Sc-PDSI and the assumptions of the Palmer Drought Model (PDM) the precipitation required for drought termination (when Sc-PDSI reaches −0.5) and amelioration (when Sc-PDSI reaches −2.0) are computed for periods of 1, 3 and 6 months. We discuss the reduction of the uncertainty in the determination of the beginning and ending of drought conditions and provide a quantitative measure of the probability that any drought could be ameliorated or terminated. We present how the spatial variability of the amount of water needed for drought recovery and the climatological probability of receiving that amount of water is determined by the local conditions against the general climate characteristics of a small area such as the Carpathian Region. Regionally, the Pannonian Basin, the Transylvanian Plateau and the external Carpathians foothills and plains in the southern and eastern part of the region require the highest quantity of precipitation to recover from a drought while having the lowest climatological probabilities for such amounts of rainfall. High precipitation amounts over the North and northwest part of the region result in higher soil moisture supplies and higher climatological probabilities to end a given drought event. Moreover the succession and/or predominance of particular types of general atmospheric circulation patterns produce a seasonal cycle and inter-annual variability of precipitation that is quantitatively reflected in the excess of precipitation above normal required for drought recovery. Overall, the results of this study provide an overview on the chances of recovery from a drought period with moderate or severe drought and present information useful in decision making in water and drought management.

scholarly journals Attribution Analysis of Hydrological Drought Risk Under Climate Change and Human Activities: A Case Study on Kuye River Basin in China

Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1958 ◽  
Author(s):  
Zhang ◽  
Wang ◽  
Zhou
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Human Activities ◽  
Large Scale ◽  
Research Area ◽  
Drought Severity ◽  
Drought Risk ◽  
Drought Duration ◽  
Recurrence Period ◽  
The Impact

This study conducted quantitative diagnosis on the impact of climate change and human activities on drought risk. Taking the Kuye river basin (KRB) in China as the research area, we used variation point diagnosis, simulation of precipitation and runoff, drought risk assessment, and attribution quantification. The results show that: (1) the annual runoff sequence of KRB changed significantly after 1979, which was consistent with the introduction of large-scale coal mining; (2) under the same drought recurrence period, the drought duration and severity in the human activity stage were significantly worse than in the natural and simulation stages, indicating that human activities changed the drought risk in this area; and (3) human activities had little impact on drought severity in the short duration and low recurrence period, but had a greater impact in the long duration and high recurrence period. These results provide scientific guidance for the management, prevention, and resistance of drought; and guarantee sustainable economic and social development in the KRB.

scholarly journals Research on Occurrence and Development of Pasture Drought Events in Alpine Grassland using the Drought Threshold

2018 ◽  
Author(s):  
Tiaofeng Zhang ◽  
Lin Li ◽  
Hongbin Xiao ◽  
Hongmei Li
Keyword(s):  
Soil Moisture ◽  
Alpine Grassland ◽  
Soil Drought ◽  
Severe Drought ◽  
Drought Event ◽  
Drought Intensity ◽  
Quantitative Expression ◽  
Initial Soil Moisture ◽  
Initial Soil ◽  
The Relationship

Abstract. Pasture is vital to livestock husbandry development in Qinghai and even in North China. Drought is the primary meteorological disaster that affects pasture, but insufficient soil moisture is the most prominent cause of pasture drought. Timely and accurate determination of the soil moisture threshold of pasture is important for objective recognition and monitoring of the occurrence and development of pasture drought. This study aims at investigating pasture responses to soil drought as well as quantitative expression of soil drought degree and drought threshold. Test plots were selected from the pasture test station. Five testing groups were set according to coverage rate (0–100 %) at the initiation the pasture growth period. The impacts of profile moisture characteristics, drought threshold, and precipitation on duration of pasture drought were studied. Research results have demonstrated that moisture in the soil profile below 20 cm decreases slightly throughout drought events in alpine grassland. Changes of soil moisture in the 0–20 cm layer can generally reflect drought stress of the pasture. In the process of a drought event, the relationship between soil water storage and cumulative relative water loss can be expressed via a logarithmic linear equation. Quantitative expression of drought degree in grasslands can be realized by transforming the slope of this equation into the index D with an interval of [0, 1]. The occurrence rates of mild drought,moderate drought, and severe drought were 0.36, 0.45, and 0.70, respectively. The duration of severe drought was closely related with initial soil moisture. The relationship between duration of drought and the necessary minimum precipitation can be expressed by an exponential equation. Values of the D index can express soil drought intensity and pasture drought intensity. The durations for different grades of drought events were correlated with both initial soil moisture and previous precipitation. The conclusions of this study can provide scientific references for the objective understanding onoccurrence, development, monitoring, and early warning of pasture drought.

scholarly journals Drought Analysis in the Yellow River Basin Based on a Short-Scalar Palmer Drought Severity Index

Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1526 ◽  
Author(s):  
Ye Zhu ◽  
Yi Liu ◽  
Xieyao Ma ◽  
Liliang Ren ◽  
Vijay Singh
Keyword(s):  
Soil Moisture ◽  
Time Scale ◽  
Palmer Drought Severity Index ◽  
Yellow River ◽  
Severity Index ◽  
Yellow River Basin ◽  
Drought Severity ◽  
The Yellow River ◽  
The Yellow River Basin ◽  
Drought Severity Index

Focusing on the shortages of moisture estimation and time scale in the self-calibrating Palmer drought severity index (scPDSI), this study proposed a new Palmer variant by introducing the Variable Infiltration Capacity (VIC) model in hydrologic accounting module, and modifying the standardization process to make the index capable for monitoring droughts at short time scales. The performance of the newly generated index was evaluated over the Yellow River Basin (YRB) during 1961–2012. For time scale verification, the standardized precipitation index (SPI), and standardized precipitation evapotranspiration index (SPEI) at a 3-month time scale were employed. Results show that the new Palmer variant is highly correlated with SPI and SPEI, combined with a more stable behavior in drought frequency than original scPDSI. For drought trend detection, this new index is more inclined to reflect comprehensive moisture conditions and reveals a different spatial pattern from SPI and SPEI in winter. Besides, two remote sensing products of soil moisture and vegetation were also employed for comparison. Given their general consistent behaviors in monitoring the spatiotemporal evolution of the 2000 drought, it is suggested that the new Palmer variant is a good indicator for monitoring soil moisture variation and the dynamics of vegetation growth.

scholarly journals Commonly Used Drought Indices as Indicators of Soil Moisture in China

2015 ◽  
Vol 16 (3) ◽  
pp. 1397-1408 ◽  
Author(s):  
Hongshuo Wang ◽  
Jeffrey C. Rogers ◽  
Darla K. Munroe
Keyword(s):  
Soil Moisture ◽  
Time Scales ◽  
Standardized Precipitation Index ◽  
Meteorological Drought ◽  
Severity Index ◽  
Agricultural Drought ◽  
Weather Data ◽  
Drought Indices ◽  
Drought Severity ◽  
Better Than

Abstract Soil moisture shortages adversely affecting agriculture are significantly associated with meteorological drought. Because of limited soil moisture observations with which to monitor agricultural drought, characterizing soil moisture using drought indices is of great significance. The relationship between commonly used drought indices and soil moisture is examined here using Chinese surface weather data and calculated station-based drought indices. Outside of northeastern China, surface soil moisture is more affected by drought indices having shorter time scales while deep-layer soil moisture is more related on longer index time scales. Multiscalar drought indices work better than drought indices from two-layer bucket models. The standardized precipitation evapotranspiration index (SPEI) works similarly or better than the standardized precipitation index (SPI) in characterizing soil moisture at different soil layers. In most stations in China, the Z index has a higher correlation with soil moisture at 0–5 cm than the Palmer drought severity index (PDSI), which in turn has a higher correlation with soil moisture at 90–100-cm depth than the Z index. Soil bulk density and soil organic carbon density are the two main soil properties affecting the spatial variations of the soil moisture–drought indices relationship. The study may facilitate agriculture drought monitoring with commonly used drought indices calculated from weather station data.

scholarly journals Understanding the Sensitivity of Different Drought Metrics to the Drivers of Drought under Increased Atmospheric CO2

2011 ◽  
Vol 12 (6) ◽  
pp. 1378-1394 ◽  
Author(s):  
Eleanor J. Burke
Keyword(s):  
Soil Moisture ◽  
Standard Deviation ◽  
Climate Model ◽  
Relative Sensitivity ◽  
Severity Index ◽  
Atmospheric Co2 ◽  
Drought Severity ◽  
Available Energy ◽  
The Mean ◽  
Hadley Centre

Abstract A perturbed physics Hadley Centre climate model ensemble was used to study changes in drought on doubling atmospheric CO2. The drought metrics analyzed were based on 1) precipitation anomalies, 2) soil moisture anomalies, and 3) the Palmer drought severity index (PDSI). Drought was assumed to occur 17% of the time under single CO2. On doubling CO2, in general, PDSI drought occurs more often than soil moisture drought, which occurs more often than precipitation drought. This paper explores the relative sensitivity of each drought metric to changes in the main drivers of drought, namely precipitation and available energy. Drought tends to increase when the mean precipitation decreases, the mean available energy increases, the standard deviation of precipitation increases, and the standard deviation of available energy decreases. Simple linear approximations show that the sensitivity of drought to changes in mean precipitation is similar for the three different metrics. However, the sensitivity of drought to changes in the mean available energy (which is projected to increase under increased atmospheric CO2) is highly dependent on metric: with PDSI drought the most sensitive, soil moisture less sensitive, and precipitation independent of available energy. Drought metrics are only slightly sensitive to changes in the variability of the drivers. An additional driver of drought is the response of plants to increased CO2. This process reduces evapotranspiration and increases soil moisture, and generally causes less soil moisture drought. In contrast, the associated increase in available energy generally causes an increase in PDSI drought. These differing sensitivities need to be taken into consideration when developing adaptation strategies.

Long lead statistical forecasts of area burned in western U.S. wildfires by ecosystem province

2002 ◽  
Vol 11 (4) ◽  
pp. 257 ◽  
Author(s):  
Anthony L. Westerling ◽  
Alexander Gershunov ◽  
Daniel R. Cayan ◽  
Tim P. Barnett
Keyword(s):  
Soil Moisture ◽  
Large Scale ◽  
Forecast Model ◽  
Severity Index ◽  
Fire Season ◽  
Drought Severity ◽  
Canonical Correlations ◽  
Area Burned ◽  
Wildfire Season ◽  
Random Guess

A statistical forecast methodology exploits large-scale patterns in monthly U.S. Climatological Division Palmer Drought Severity Index (PDSI) values over a wide region and several seasons to predict area burned in western U.S. wildfires by ecosystem province a season in advance. The forecast model, which is based on canonical correlations, indicates that a few characteristic patterns determine predicted wildfire season area burned. Strong negative associations between anomalous soil moisture (inferred from PDSI) immediately prior to the fire season and area burned dominate in most higher elevation forested provinces, while strong positive associations between anomalous soil moisture a year prior to the fire season and area burned dominate in desert and shrub and grassland provinces. In much of the western U.S., above- and below-normal fire season forecasts were successful 57% of the time or better, as compared with a 33% skill for a random guess, and with a low probability of being surprised by a fire season at the opposite extreme of that forecast.

scholarly journals Using the Local Drought Data and GRACE/GRACE-FO Data to Characterize the Drought Events in Mainland China from 2002 to 2020

2021 ◽  
Vol 11 (20) ◽  
pp. 9594
Author(s):  
Lilu Cui ◽  
Cheng Zhang ◽  
Zhicai Luo ◽  
Xiaolong Wang ◽  
Qiong Li ◽  
...  
Keyword(s):  
Mainland China ◽  
Severity Index ◽  
Precipitation Anomaly ◽  
Probability Of Detection ◽  
Drought Severity ◽  
Drought Event ◽  
Loss Assessment ◽  
Drought Characteristics ◽  
Disaster Loss ◽  
Gravity Recovery

Accurate quantification of drought characteristics helps to achieve an objective and comprehensive analysis of drought events and to achieve early warning of drought and disaster loss assessment. In our study, a drought characterization approach based on drought severity index derived from Gravity Recovery and Climate Experiment (GRACE) and its Follow-On (GRACE-FO) data was used to quantify drought characteristics. In order to improve drought detection capability, we used the local drought data as calibration criteria to improve the accuracy of the drought characterization approach to determine the onset of drought. Additionally, the local precipitation data was used to test drought severity determined by the calibrated drought characterization approach. Results show that the drought event probability of detection (POD) of this approach in the four study regions increased by 61.29%, 25%, 94.29%, and 66.86%, respectively, after calibration. We used the calibrated approach to detect the drought events in Mainland China (MC) during 2016 and 2019. The results show that CAR of the four study regions is 100.00%, 92.31%, 100.00%, and 100.00%. Additionally, the precipitation anomaly index (PAI) data was used to evaluate the severity of drought from 2002 to 2020 determined by the calibrated approach. The results indicate that both have a strong similar spatial distribution. Our analysis demonstrates that the proposed approach can serve a useful tool for drought monitoring and characterization.

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