SEMINAR: Tuesday 3/12: MGG Student Seminar

["Katherine Inderbitzen" <kinderbitzen@rsmas.miami.edu>]

Tuesday, April 12, at noon in the CIMAS conference room

Monica Arienzo: What drives lamination formation in stalagmites from the
Bahamas?

When stalagmites are cut along the growth axis, layering is reveled. Very
few studies have been conducted on speleothem laminations. This is
primarily due to the low growth rate of speleothems (typically 10 m/year)
and also due to a lack of understanding of the factors driving lamination
formation (Tan et al., 2006). There are thought to be two main drivers for
the formation of laminations. Laminations are either formed by a more arid
environment leading to the decreased growth rate and increased clay
particle and/or organic deposition. Additionally, laminations can develop
by an increased rainfall leading to an enhanced entrainment of organic
material and/or clay particles in drip water. In order to determine the
factors driving lamination formation, a grey scale image of one stalagmite
from the Bahamas was analyzed for the pixel-by-pixel grey scale value
along the growth axis. The grey scale variability was then compared to the
oxygen and carbon isotope record from the same sample. It has been well
documented that subtropical speleothem carbon and oxygen isotopes are
driven by the amount of rainfall. As precipitation increases, the carbon
and oxygen isotopes will decrease. Therefore, by looking at the
relationship of laminations and carbon and oxygen isotopes, the driver of
laminations can be determined. The results demonstrate that the grey scale
value is inversely related to the isotopic value supporting that darker
lamina form during periods of increased aridity. This method shows promise
for application to better understanding lamination formation in
speleothems and also can be applied to a wide range of laminated datasets.



Emanuelle Feliciano: Measuring Above Ground Biomass and Vegetation
Structure in the South
Florida Everglades Wetland Ecosystem using LiDAR and SAR

Worldwide, anthropogenic activities are disturbing and disrupting nutrient
rich bio-diverse wetland ecosystems. Disturbance of the South Florida
Everglades has been particularly acute, but difficult to quantify given
its limited accessibility. Successful ecosystem monitoring requires the
use of remote sensing. We used space-based Synthetic Aperture Radar (SAR)
observations in the X-, C-, and L-bands to estimate vegetation structure
and above-ground biomass and track their changes over time.

In order to calibrate the multi-wavelength and multi-polarization SAR
observations, we conducted field measurement in three vegetation
communities: hammock, pine and cypress. Our ground measurements included
both traditional forestry surveys and state-of-the-art Terrestrial Laser
Scanning (TLS), a.k.a. ground based LiDAR surveys. A week long TLS survey
was conducted in the Everglades National Park in the three calibrations
sites using a Leica ScanStation C10 TLS instrument which utilizes a
narrow, green (532 nm) laser beam. During this week we collected a total
of 29 scans (33 GB of data). The TLS surveys provided centimeter
resolution 3-D point clouds of the ground surface and below-canopy
vegetation.

Initial analysis of the data has provided detailed 3-D estimates of the
vegetation structure and above ground biomass. A comparative analysis of
the ability of the three bands of SAR to quantify above ground biomass in
the different communities is presented. We also determine the essential
bands needed to most efficiently estimate biomass. We find that the
performance of SAR differs by community types. More rigorous data
processing will provide important quantitative measures that will allow
careful calibration of the remote sensing SAR data.


***************************
Katherine Inderbitzen
Rosenstiel School of Marine & Atmospheric Science
Marine Geology & Geophysics
kinderbitzen@rsmas.miami.edu


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