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Free‐rising, tethered CTD profiler: increased vertical resolution and near surface profiling
Author(s) -
Maske Helmut,
Ochoa José,
Jáureguí César Almeda,
Avendaño Andrés Carrasco
Publication year - 2012
Publication title -
limnology and oceanography: methods
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.898
H-Index - 72
ISSN - 1541-5856
DOI - 10.4319/lom.2012.10.475
Subject(s) - ctd , thermocline , turbidity , remote sensing , water column , environmental science , stratification (seeds) , profiling (computer programming) , geology , oceanography , computer science , seed dormancy , botany , germination , dormancy , biology , operating system
The formation of a diurnal thermocline at few meters depth is difficult to document because of the mixing induced by research platforms. We built a free‐rising CTD‐platform, including sensors for chlorophyll fluorescence, turbidity, and light, that profiles to ~0.4 m below the surface with better than 0.03 m resolution and at sufficient distance from the research platform to measure an undisturbed water column. The profiler, with a practical maximum depth of 100 m is controlled mechanically using sacrificial weights and a safety tether that assures easy recovery of the instrument. The design concept is easily adapted to many commercial CTD models. Off Baja California, most profiles showed temperature stratification near the surface and some profiles showed near surface chlorophyll fluorescence thin layers; these features would be difficult to observe with normal CTD profilers.