A mathematical morphology approach for a qualitative exploration of drought events in space and time

Vernieuwe, Hilde; Baets, Bernard De; Verhoest, Niko

doi:10.1002/joc.6226

Cited by 15 publications

(19 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We improve the robustness of the identification of moisture deficit clusters by first applying a 2‐D median filter to the global map of P − E percentiles at each time step (Figure S2). This spatial smoothing reduces small‐scale heterogeneity and is a common preprocessing step in drought clustering analyses (Andreadis et al, 2005; Herrera‐Estrada et al, 2017; Sheffield et al, 2009; Vernieuwe et al, 2019).…”

Section: Methodsmentioning

confidence: 99%

Landfalling Droughts: Global Tracking of Moisture Deficits From the Oceans Onto Land

Herrera-Estrada

Diffenbaugh

2020

Water Resources Research

View full text Add to dashboard Cite

Droughts threaten food, energy, and water security, causing death and displacement of millions of people and billions of dollars in damages. However, there are still important gaps in the understanding of drought mechanisms and behaviors, inhibiting the accuracy of early-warning systems designed to protect communities worldwide. We use an object-tracking algorithm to track clusters of precipitation-minus-evaporation moisture deficits across land and ocean areas of the globe from 1981-2018. This analysis reveals a new type of "landfalling drought" that originates over the ocean and "migrates" onto land. We find that 16% of droughts that affected the continents worldwide from 1981-2018 were landfalling droughts. These droughts were significantly larger (220-425%) and more intense (4-30%)-and grew (253-285%) and intensified (9-28%) faster-than droughts that developed solely over the land or ocean. To identify potential underlying mechanisms, we analyze moisture transport associated with landfalling droughts over western North America. We find that landfalling droughts in this region are associated with anomalously anticyclonic atmospheric pressure patterns that reduce moisture fluxes over the Pacific Ocean toward the continent. By advancing understanding of the spatiotemporal evolution of droughts, our findings offer the potential to improve seasonal-scale prediction and long-term projection of global drought risks. Plain Language Summary Droughts can have devastating impacts on a region's domestic water supply, electricity generation, agriculture, and ecosystem health. However, the processes by which droughts arise, develop, and end are not yet fully understood, creating barriers for accurate prediction. In this study, we define droughts as instances when the quantity of precipitation minus evaporation is below normal, allowing us to identify droughts over both the land and ocean. Tracking droughts from where they start to where they end reveals that 16% of droughts that affect continents start over the ocean and travel onto land. We find that these "landfalling droughts" are larger, more intense, and grow faster after making landfall, compared to droughts that start and end completely over land. While the role of sea surface temperatures has been studied in relation to drought development over the continents, fewer studies have analyzed moisture deficits over the oceans. Our results suggest that monitoring and tracking moisture deficits offshore has the potential to yield improvements in drought prediction, warning, and preparation. Recent advances in satellite observations, climate modeling, and computing have improved global drought monitoring and forecasting capabilities (Wood et al., 2015). Much of the predictive capacity arises from the ocean's role in drought development (

show abstract

Section: Methodsmentioning

confidence: 99%

Landfalling Droughts: Global Tracking of Moisture Deficits From the Oceans Onto Land

Herrera-Estrada

Diffenbaugh

2020

Water Resources Research

View full text Add to dashboard Cite

show abstract

“…e method divided inundation extent into water-body extent and water-invasion extent with high timeliness and accuracy. It is worth mentioning that Vernieuwe et al [25] have put forward a Mathematical Morphology approach for a qualitative exploration of drought events in space and time.…”

Section: Space-filling Methodmentioning

confidence: 99%

“…For the purpose of analyzing the accuracy of different methods, we estimated the inundation depth and inundation extent caused by the Sanhekou Reservoir at water volume of 1910 × 10 6 m 3 and 2349 × 10 6 m 3 , as shown in Table 1. HD represents the hydrodynamic method proposed in the literature [2], SF is the space-filling method put forward in the literature [20], LM is the method of simple expansion indicated in the literature [25], and MM represents the method proposed in this paper.…”

Section: Accuracy Analysismentioning

confidence: 99%

Estimation Method of Inundation Extent Based on Mathematical Morphology

Lai

Safonov

2019

Mathematical Problems in Engineering

View full text Add to dashboard Cite

Estimation of inundation extent is critical for the flood control system. It helps decision-maker determine the scope of damage to save residents' lives and property. In this paper, we analyzed the drawbacks of two kinds of methods of inundation estimation, hydrodynamic method and space-filling method, and divided inundation extent into water-body extent and water-invasion extent for the purpose of enhancing estimation accuracy. Based on Mathematical Morphology, an inundation estimation method suitable for flood mapping around natural and artificial lakes was put forward by integrating remote sensing (RS) data and digital elevation model (DEM) data. is method consists of three aspects, including the subdivision of water-body extent, the deduction of water-invasion extent which is viewed as the expansion of water-body extent, and the smoothing the boundaries of waterinvasion extent. With subdividing DEM data horizontally into cross sections to build equiangular subsets, the expansion operation was implemented by structuring elements which were established based on set operations and scalar flexibilities. us, water-invasion extent was easily described by the structuring elements under given water volume, so that inundation extent was conveniently estimated by spatial data. e experiment results show that the method has the advantages of high accuracy and expressiveness and low time consumption. It had been used to analyze the inundation caused by the water conservancy project named Hanjiang-to-Weihe River Water Transfer Project in China. e method served as decision support for building an efficient emergency response mechanism and helped implement flood disaster forecast and simulation.

show abstract

“…In this paper, the methodology is presented for providing an answer for both options. To illustrate the approach, we make use of a database containing characteristics of drought events in mainland Australia as characterised by Vernieuwe et al [4].…”

Section: Introductionmentioning

confidence: 99%

“…As stated before, this paper introduces two options that allow for a more effective communication about droughts. To demonstrate this, we make use of a database assembled by Vernieuwe et al [4]. Yet, other databases could have been used as well.…”

Section: Introductionmentioning

confidence: 99%

Effective Drought Communication: Using the Past to Assess the Present and Anticipate the Future

Vernieuwe

Baets

Verhoest

2021

Water

Self Cite

View full text Add to dashboard Cite

Especially during drought events, it is important that water gets properly allocated and is not misused or wasted. For an effective drought management, it is thus of utmost importance to raise the awareness of water managers as well as the general public about the drought’s severity. In this paper, we provide two possible sources of information that can be used to communicate about drought events. To illustrate our approach, we make use of drought events that were identified in preceding work as connected components in space and time through the use of operators from the field of mathematical morphology and summarized in terms of characteristics such as affected area, duration and intensity. We demonstrate how these drought characteristics can be used to query for historical drought events that are most similar to an ongoing event, such that lessons learnt from the management of past events can be incorporated in the management of the ongoing event. Further, we also demonstrate how a probabilistic model describing the dependence structure between the drought characteristics is identified and how such model can serve as a basis to estimate the severity of the event. Both approaches provide information that can be used to communicate to laymen about the severity of the ongoing drought, which will help them to anticipate the future.

show abstract

A mathematical morphology approach for a qualitative exploration of drought events in space and time

Cited by 15 publications

References 41 publications

Landfalling Droughts: Global Tracking of Moisture Deficits From the Oceans Onto Land

Landfalling Droughts: Global Tracking of Moisture Deficits From the Oceans Onto Land

Estimation Method of Inundation Extent Based on Mathematical Morphology

Effective Drought Communication: Using the Past to Assess the Present and Anticipate the Future

Contact Info

Product

Resources

About