20 Remote Sensing of African Lakes: A Review
419
20.6.4 A Field Progressing
The field of remote sensing, in general, and the applications of remote sensing to
Africa specifically, are rapidly progressing. On a practical “access” level, much of
the imagery discussed here can be downloaded for free. Where Internet connections
are an issue, the ESA has launched the “TIGER Initiative” to ensure distribution of
images in addition to other capacity building. Additionally, more undersea cables
will increase bandwidth.
Technically, there are many interesting developments. The statistical analysis of
the relative variability of remotely-sensed variables (climate, hydrological and biological), has allowed for new insights in lake functioning based on limited calibration
data (Bergamino et al. 2007; Cózar et al. 2012). Using multiannual optical time series
with monthly or shorter periodicity, this approach has proven successful for identifying important basin-scale features of several of the larger lakes. The analysis of
common patterns in lacustrine systems remains still unexplored, but it is apparently
suitable for the Eastern Africa region, where the spatial density of lakes is relatively high. The analysis of the relative optical variability will likely provide further
valuable information on the processes controlling the dynamics of African lakes.
However, the advancement and successful deployment of remote sensing techniques
for the study and management of African lakes require more accurate estimates of
specific biogeochemical water properties (e.g. Matthews et al. 2012).
As progress is made, it is interesting to imagine what an ideal future might look
like for remote sensing of African lakes. More sensors would be available, not only
to replace past and current ones (such as the Landsat Data Continuity Mission) but
to expand spatial, spectral, temporal and radiometric capacity for satellite-based
monitoring. The capacity of African scientists and lake managers would be increased through local and international cooperation. The ability to download large
files would approach current high-income nation standards through more bandwidth
and more stable connections (including electricity). The availability of regular standardized field data for algorithm development and validation would be increased.
The understanding of the advantages of remote sensing technology for integrated
lake-catchment management by national and international decision makers and stakeholders would improve. Finally, links between the remote sensing of lakes and the
remote sensing of the land in their drainage basins would be strengthened.
References
Awange JL, Sharifi MA, Ogonda G, Wickert J, Grafarend EW, Omulo MA (2008) The falling lake
Victoria water levels: GRACE, TRIMM and CHAMP satellite analysis of the lake Basin. Water
Resour Manage 22:775–796. doi:10.1007/s11269-007-9191-y
Becker M, Llovel W, Cazenave A, Güntner A, Crétaux J-F (2010) Recent hydrological behavior
of the East African great lakes region inferred from GRACE, satellite altimetry and rainfall
observations. C.R. Geosci 342:223–233. doi:10.1016/j.crte.2009.12.010
419
20.6.4 A Field Progressing
The field of remote sensing, in general, and the applications of remote sensing to
Africa specifically, are rapidly progressing. On a practical “access” level, much of
the imagery discussed here can be downloaded for free. Where Internet connections
are an issue, the ESA has launched the “TIGER Initiative” to ensure distribution of
images in addition to other capacity building. Additionally, more undersea cables
will increase bandwidth.
Technically, there are many interesting developments. The statistical analysis of
the relative variability of remotely-sensed variables (climate, hydrological and biological), has allowed for new insights in lake functioning based on limited calibration
data (Bergamino et al. 2007; Cózar et al. 2012). Using multiannual optical time series
with monthly or shorter periodicity, this approach has proven successful for identifying important basin-scale features of several of the larger lakes. The analysis of
common patterns in lacustrine systems remains still unexplored, but it is apparently
suitable for the Eastern Africa region, where the spatial density of lakes is relatively high. The analysis of the relative optical variability will likely provide further
valuable information on the processes controlling the dynamics of African lakes.
However, the advancement and successful deployment of remote sensing techniques
for the study and management of African lakes require more accurate estimates of
specific biogeochemical water properties (e.g. Matthews et al. 2012).
As progress is made, it is interesting to imagine what an ideal future might look
like for remote sensing of African lakes. More sensors would be available, not only
to replace past and current ones (such as the Landsat Data Continuity Mission) but
to expand spatial, spectral, temporal and radiometric capacity for satellite-based
monitoring. The capacity of African scientists and lake managers would be increased through local and international cooperation. The ability to download large
files would approach current high-income nation standards through more bandwidth
and more stable connections (including electricity). The availability of regular standardized field data for algorithm development and validation would be increased.
The understanding of the advantages of remote sensing technology for integrated
lake-catchment management by national and international decision makers and stakeholders would improve. Finally, links between the remote sensing of lakes and the
remote sensing of the land in their drainage basins would be strengthened.
References
Awange JL, Sharifi MA, Ogonda G, Wickert J, Grafarend EW, Omulo MA (2008) The falling lake
Victoria water levels: GRACE, TRIMM and CHAMP satellite analysis of the lake Basin. Water
Resour Manage 22:775–796. doi:10.1007/s11269-007-9191-y
Becker M, Llovel W, Cazenave A, Güntner A, Crétaux J-F (2010) Recent hydrological behavior
of the East African great lakes region inferred from GRACE, satellite altimetry and rainfall
observations. C.R. Geosci 342:223–233. doi:10.1016/j.crte.2009.12.010