Wetland Landscape Characterization

Detection of Small Wetlands with Multi Sensor Data in East Africa

“…[21,24] note that C-band SAR is primarily useful in sensing the characteristics of relatively sparse and short layers of vegetation and it is very useful in distinguishing herbaceous wetlands from clearing. Generally L-band SAR is seen to perform better in detection and differentiation of wetland types as also noted by [21][22][23][24][25][26] than C-band due to its ability to penetrate much into the vegetation canopy. Nevertheless, L-band data results were too generalized, i.e., a larger than expected wetland area was delineated.…”

“…This is attributed to their higher resolution of 0.25 m. The detailed information obtained was very useful in the classification process and differentiation of the land uses. The importance of aerial photographs in detection and delineation of small wetlands is also emphasized in the literature [3,[19][20][21][24][25][26]. In addition to their usefulness in detailed mapping of the wetlands, they are indeed effective in boundary delineation.…”

“…It is, however, also important to note that the strengths of SAR as an appropriate tool for wetlands detection reside in the sensitivity of radar backscatter to the dielectric properties (soil and vegetation moisture content) and geometric (surface roughness) attributes of imaged surface; the higher the moisture content, the higher the dielectric constant and the stronger the signal and vice versa [12]. Thus the size of wetlands changes rapidly with occurrence of increased moisture content in the soil [13,25]. This could also explain why flood plains were easily detected because some parts were very wet and covered with natural wetland vegetation like papyrus and reeds compared to inland valleys.…”

Random sets to model uncertainty in remotely sensed objects

“…They have important functions in minimizing the effects of flooding and erosion as well as in recharging of ground water. A wetland is usually characterized by a dominance of wetland plants, soils subjects to waterlog and indicators of wetland water regime [97]. Remote sensing images have been used to obtain information about these criteria for identifying wetlands, detecting their changes over time and monitoring the effects of human influences [e.g., 64,77,83,102,127].…”

“…Wetlands experiencing periodic flooding exhibit changes in the spatial distribution and temporal duration of inundation areas. A better understanding of wetland dynamics is important for the wetland ecosystem monitoring and habitat assessment [97].…”