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February 2014
Remote Sensing of Drought:
Innovative Monitoring Approaches
Edited by Brian D. Wardlow, Martha C.
Anderson, and James P. Verdin
CRC Press, Taylor and Francis: Boca Raton, London, New
York. 2012. 422 pages, list of contributors, maps, figures; 20
pages color plates, references
ISBN 978-1-4398-3557-9 (hardcover)
Reviewed by:
Michael K. Crosby, Post-doctoral
Research Associate, Department of Forestry, Mis-
sissippi State University, Mississippi State, MS
The importance of water to our society has led to an
increasing demand for current, accurate information
concerning the extent, severity, and duration of drought
events. The technological advances over the course of
the past 30+ years have led to an increasing amount of
information derived from remotely-sensed sources (i.e.,
Remote Sensing of Drought: Innovative Monitoring
discusses the most recent developments
regarding drought monitoring using remotely-sensed data.
The topics covered in this book make it a valuable resource
for researchers, graduate students, and analysts interested
in the early detection and monitoring of drought events.
The book comprises five parts, containing 16 chapters from
48 contributors. Aside from an introductory and summary
chapter, the other 14 are divided into four parts in rela-
tion to components of the hydrologic cycle, 1) vegetation, 2)
evapotranspiration, 3) soil moisture and groundwater, and
4) precipitation. This logical grouping, and the inclusion of a
‘Contents’ section at the beginning of each chapter, allows the
reader to easily find desired information.
Chapter 1 serves as an introduction to drought monitor-
ing, giving a historical perspective as well as discussing
some current efforts. The authors discuss indices developed
to assess drought (e.g., Palmer’s Drought Severity Index) as
well as potential shortcomings. They then introduce efforts
to incorporate satellite remote sensing into drought monitor-
ing efforts and initiatives to create Drought Early Warning
Systems (DEWS).
Part 1 comprises four chapters that focus on drought mon-
itoring of vegetated areas. Chapter 2 provides an overview of
the role of remote sensing in vegetation drought monitoring
through the development of indices related to plant vigor/
moisture content (e.g., Normalized Difference Vegetation
Index) and the evolution and development of additional indi-
ces. The incorporation of remotely-sensed data with climatic
and biophysical variables is covered in Chapter 3, where the
authors detail the development of the Vegetation Drought
Response Index (VegDRI) for operational drought monitoring.
A treatment of forecasting future vegetation conditions, and
the importance of vegetation indices, is provided in Chapter
4. Chapter 5 provides a different look at vegetation drought
monitoring by analyzing the fraction of absorbed photosyn-
thetically active radiation over vegetated areas.
In Part 2, there are three chapters that deal with estimat-
ing evapotranspiration (ET) and its importance in drought
monitoring. Chapter 6 details the development of two models
for estimating ET for operational drought monitoring using 1)
changes in soil moisture using a vegetative water budget and
2) differences in surface energy balance. The development
of a multi-scale model for determining ET using thermal
infrared imagery (the Evaporative Stress Index, or ESI) is
explained in Chapter 7. Chapter 8 outlines the function of
remotely-sensed data in an ET model, as well as the utility of
a model for monitoring drought in Kenyan croplands.
A variety of methods for assessing soil moisture are provid-
ed in Part 3. Chapter 9 summarizes a method for estimating
soil moisture for drought monitoring using microwave remote
sensing. Chapter 10 provides an overview of the current
development of the North American Land Data Assimila-
tion System, which is used to assess and forecast drought
conditions in the United States. An interesting program for
estimating terrestrial water storage by analyzing changes in
satellite positions, called the Gravity Recovery and Climate
Experiment (GRACE), is discussed in Chapter 11.
Part 4 is composed of four chapters that deal with monitor-
ing precipitation. Chapter 12 provides a discussion of mon-
itoring precipitation through both in situ (e.g., rain gauges)
and remotely-sensed observations and the importance/short-
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