A daily drought index based on evapotranspiration and its application in regional drought analyses

Abstract Drought is a natural phenomenon caused by extreme and persistent precipitation shortage. This shortfall causes impacts on hydrology, agriculture, and the economy of a country. Secondly, drought/dryness has certain unique characteristics (severity, duration) among the natural hazards which makes it difficult to classify the persistent and subjective network of impacts. Drought classification is important to manage drought, allowing both quantitative evaluation and potential risk assessment planning. The simpler approach of drought indices made it easier for various researchers and organizations to classify drought. Several drought indices have been proposed at the national and global level to characterize hydrological, meteorological and agricultural droughts. Until now, there has been no widely agreed drought index among researchers. Therefore, researchers are trying to modify and reconstruct a simple, complete, and robust drought index for effective use and planning of the management of water resources. Due to the complex terrestrial ecosystem, researchers used to integrate multiple drought indexes for evaluation and monitoring of regional drought conditions. The reviewed composite or aggregated indices revealed that the researchers are mainly focused on regional climatic and environmental conditions, and differences of theoretical backgrounds while integrating a drought index. There is a lack of performance evaluation of these indices because usually the comparative analysis between the integrated index and earlier developed composite indices is not performed. Secondly, the developer researchers did not mention limitations such as data, which is considered a paramount issue while applying these indices in other regions. Therefore, there is still comprehensive work needed for the simple integration of drought indexes for general applications.

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Estimation of annual regional drought index considering the joint effects of climate and water budget for Krishna River basin, India

Environmental Monitoring and Assessment ◽

10.1007/s10661-020-08379-y ◽

2020 ◽

Vol 192 (7) ◽

Author(s):

Rehana Shaik ◽

Monish N.T. ◽

Sireesha Naidu G.

Keyword(s):

River Basin ◽

Water Budget ◽

Drought Index ◽

Joint Effects ◽

Regional Drought

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Use Of a New Agricultural Drought Index Within a Regional Drought Observatory

Methods and Tools for Drought Analysis and Management - Water Science and Technology Library ◽

10.1007/978-1-4020-5924-7_6 ◽

2007 ◽

pp. 103-124 ◽

Cited By ~ 4

Author(s):

A. Matera ◽

G. Fontana ◽

V. Marletto ◽

F. Zinoni ◽

L. Botarelli ◽

...

Keyword(s):

Drought Index ◽

Agricultural Drought ◽

Regional Drought

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Regional Drought Assessment Based on the Reconnaissance Drought Index (RDI)

Water Resources Management ◽

10.1007/s11269-006-9105-4 ◽

2006 ◽

Vol 21 (5) ◽

pp. 821-833 ◽

Cited By ~ 328

Author(s):

G. Tsakiris ◽

D. Pangalou ◽

H. Vangelis

Keyword(s):

Drought Index ◽

Reconnaissance Drought Index ◽

Drought Assessment ◽

Regional Drought

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Assessing the Remotely Sensed Evaporative Drought Index for Drought Monitoring over Northeast China

Remote Sensing ◽

10.3390/rs11171960 ◽

2019 ◽

Vol 11 (17) ◽

pp. 1960 ◽

Cited By ~ 2

Author(s):

Lilin Zhang ◽

Yunjun Yao ◽

Xiangyi Bei ◽

Kun Jia ◽

Xiaotong Zhang ◽

...

Keyword(s):

Northeast China ◽

Drought Index ◽

Crop Yields ◽

Standardized Precipitation Index ◽

Drought Monitoring ◽

Drought Condition ◽

The West ◽

Moisture Condition ◽

West Part ◽

Regional Drought

Many existing satellite evapotranspiration (ET)-based drought indices have characterized regional drought condition successfully, but the relatively short time span of ET products limits their use in long-term climatological drought assessment. In this study, we assess Evaporative Drought Index (EDI) as a drought monitoring indicator over Northeast China through a retrospective comparison with drought-related indicators. After verifying its utility for detecting documented regional drought events and impacts of drought on crop production, we apply it to improve our understanding of the variation in dryness over Northeast China from 1982 to 2015. Our results illustrate that EDI is generally effective for characterizing terrestrial moisture condition and its standardized formula, namely, Standardized Evaporative Drought Index (sEDI) corresponds well with historical drought events and inter-annual grain crop yields over Northeast China. Although the calculation of sEDI does not directly incorporate precipitation and soil moisture, statistical analyses indicate sEDI can detect drought in accordance with the Standardized Precipitation Index (SPI) and Palmer Drought Severity Index (PDSI), with the highest correlations found in the west part of Northeast China (R < −0.7). Further analysis illustrates sEDI is more related to commonly-used drought metrics over areas with short canopy vegetation (R < −0.5) than woodland (R < −0.2), which suggests precipitation may not be a good representative of drought condition over areas with deep-rooted vegetation. Then, we find 56.5% of Northeast China shows an upward dry trend from 1982 to 2015, which mainly concentrates in the west part of the study area. Conversely, 14.4% of Northeast China shows a significant wetted trend and most of them locate at cropland areas, due to the improved water management. This study suggests that EDI is a feasible method to monitor spatially distributed drought condition and can provide unique drought information not reflected by rainfall deficits, which also can be used to evaluate traditional precipitation-based indicators.

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Effects of different reference periods on drought index estimations for 1901–2014

10.5194/hess-2016-445 ◽

2016 ◽

Author(s):

Myoung-Jin Um ◽

Yeonjoo Kim ◽

Daeryong Park ◽

Jeong Bin Kim

Keyword(s):

West Africa ◽

East Asia ◽

Drought Index ◽

Research Unit ◽

Spatial Extent ◽

Drought Severity ◽

Climate Change Scenarios ◽

Climate Data ◽

Drought Characteristics ◽

Regional Drought

Abstract. This study aims to understand how different reference periods (i.e., calibration periods) of climate data for estimating the drought index influence regional drought assessments. Specifically, we investigate the influence of different reference periods on historical drought characteristics such as trends, frequency, intensity and spatial extents using the standard precipitation evapotranspiration index with a 12-month lag (SPEI-12) estimated from the datasets of the climate research unit (CRU) and the University of Delaware (UDEL). For the 1901–1957 (P1) and 1958–2014 (P2) estimation periods, three different types of reference periods are used: P1 and P2 together, P1 and P2 separately and P1 only. Focusing on East Asia, Europe, North America and West Africa, we find the influence of the reference periods to be significant in East Asia and West Africa, with dominant drying trends from P1 to P2. The reference periods influence the assessment of drought characteristics, particularly for severity and spatial extent, whereas their influence on the frequency is relatively small. Finally, self-calibration, which is the most common practice with an index such as SPEI, tends to underestimate the drought severity and spatial extent relative to the other approaches used in this study. Although the conclusions drawn in this study are limited to two global datasets, they nevertheless highlight the need for the reference period to be clarified in drought assessments to better understand regional drought characteristics and their temporal changes, particularly under climate change scenarios.

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