Chemistry Reference
In-Depth Information
Because these samplers physically disturb the natural state of the marine
microlayer,
in vitro
results obtained from collected samples could not be
proven to represent films in their natural state. Despite this limitation,
these studies resulted in characterisation of quasi-static film elasticities and
led to parameterisations that adequately define bounds within which the
marine microlayer typically ranges. By setting such bounds, these works
provided constraints for laboratory experiments (e.g., Hirsa et al. 1995,
McKenna 1997, Saylor 1997). At the same time, techniques for making
short wave measurements
in situ
were developed by independent re-
searchers (Hwang 1989, Bock and Hara 1995), and others have followed
(Zhang 1995, Suoja 2000).
Field measurements of the microlayer and its effects on air-sea pro-
cesses have advanced with the use of specialized sampling and measure-
ment platforms. Carlson et al. (1988) developed a small catamaran plat-
form (SCUMS,
S
elf-
C
ontained
U
nderway
M
icrolayer
S
ampler) for
making measurements of the extent of chemical enrichment (using an in-
line fluorometer and UV-absorbance detector), near-surface microstructure
(using high-resolution, fast-response temperature sensors), and surface
wave statistics (using a simple laser slope gauge). This platform was re-
fined to incorporate a fixed-point slope gauge capable of measuring tem-
poral wave spectra and was deployed during several field programs in the
Atlantic and Pacific Oceans. A scanning laser slope gauge (Bock and Hara
1995) was integrated later to allow full three-dimensional wave spectral
measurements of capillary and capillary-gravity waves (wavelengths be-
tween 7.9 x 10
-3
and 3.1 x 10
-1
m could be measured), as well as an array
of capacitive wire wave gauges to measure longer gravity waves (wave-
lengths greater than 10 m). A recent configuration of this platform (shown
in Fig. 1) was used in the Coastal Ocean Processes field experiments con-
ducted off Southern California and in the Northwestern Atlantic Ocean in
1995 and 1997. This research catamaran has the capability of simultane-
ously measuring short and long wave spectra, surface chemical enrich-
ment, wind stress, and near-surface turbulence.
