Geography Reference
In-Depth Information
on high resolution satellite images or airborne photos.
Current habitat mapping publications used a lower res-
olution platform such as Spot or Landsat. Flooding and
water physico-chemistry are often based on coarser reso-
lution images.
Temporal resolutions were often difficult to find and/or
not explicitly defined in the abstracts. We therefore sep-
arated the abstracts into several categories which imply a
certain resolution timescale rather than exact quantitative
values (Figure 1.8b). The terms 'year' and 'annual' are the
most frequent (respectively 20% and 8%) but 'early' or
'inter-annual' are less common. The term 'season' is quite
often cited (8% of MS) as well. 'Decade' and 'century'
but also 'day' or 'daily' also occurred occasionally. The
terms 'multi-temporal' or 'historic' concerns 5.5 to 6% of
MS. Interestingly, we see that 47.5% of papers mention
temporal resolution terminology. This obviously shows
the importance of monitoring work in remote sensing.
However, it also illustrates the importance and persis-
tence of satellite data as a source of data acquisition in
river sciences. Despite the lower resolution, the reliable
availability of satellite imagery at predictable time inter-
vals is a major advantage which could very well explain
the past, current and future importance of satellite data
in fluvial remote sensing.
management studies have not made heavy use of remote
sensing since spaceborne data is rarely suited to the spatial
and temporal scales which characterise river processes. In
the papers we surveyed, only a small minority exam-
ined classic river science topics such as fluvial bedforms
and channel topography, sediment calibre and dynamics
(especially in the gravel to boulder size range) and river
fauna. However, within our search results, we can clearly
see the impact of recent published works aimed at devel-
oping remote sensing technology and methods which are
tailored to river sciences and capable of providing data
acquisition strategies that are well suited to river science
investigations. Advances in imaging technology which
now allow for centimetric imagery from the air (Carbon-
neau et al., 2004; Forzieri et al., 2010) and decimetric
imagery from space (Zhang et al., 2004; Johansen et al.,
2010), new LiDAR technology which is customised to
river environments (Kinzel et al., 2007) and processing
methods designed to extract a range of features of interest
to river sciences (Carbonneau, 2005; Jordan and Fonstad,
2005; Buscombe and Masselink, 2009), have all radically
improved our capability to characterise the fluvial forms
and processes mentioned above. Given time we expect
this progress to change the overall profile of publica-
tions in fluvial remote sensing. We would therefore hope
that an identical bibliometric survey conducted in 2020
would yield a significantly enhanced list of publications
where the line between traditional river sciences and
traditional remote sensing has become blurred or even
invisible.
1.3.5 Summary
This survey of published literature in FRS illustrates some
key points about this sub-discipline of remote sensing.
Our database search revealed that over the last 35 years tra-
ditional satellite data was the major data source employed
by fluvial remote sensing studies. We found that a surpris-
ingly high proportion of published work used traditional
remote sensing data such as Landsat, ASTER and even
MODIS (Brodie et al., 2010; Liu et al., 2010; An et al.,
2011). The legacy of traditional satellite remote sensing
can also be seen in the very high number of publications
which focus on vegetation characterisation/quantification
(Laba et al., 2010; Bertoldi et al., 2011). This trend has
continued well into the twenty-first century with air-
borne data remaining in second place and, despite being
capable of higher spatial resolutions, not yet overtaking
spaceborne data in the published literature. The causes
for this are difficult to establish with certainty. How-
ever, the availability of reliable repeat (multi-temporal)
imagery from satellite sources is a likely factor. Further-
more, we believe that the dominance of satellite-based
publications also shows that classic river sciences and
1.4 Brief outline of the volume
The volume is divided into three main sections. First, we
present a series of six chapters with a slightly more
theoretical perspective on the 'Spectrum of Remote
Sensing Techniques and their Applications'. Chapter 2
explores the basic rationale for using remote sensing in
river environments. Starting from the question of 'What
can we see?' this chapter explores the possibilities and
limitations of Fluvial Remote Sensing. Chapter 3 follows
this topic with a discussion on the basic physics which
underpins the application of remote sensing to river
environments. The following chapters thenbegin address-
ing specific elements of technical progress. Chapter 4
discusses hyperspectral (very high spectral resolution)
remote sensing, while Chapter 5 deals with thermal
imagery, which is clearly of importance in the context
Search WWH ::




Custom Search