A method for correcting seal-borne oceanographic data and application to the estimation of regional sea ice thickness
| Autor: | Eamon K Frazer, Michael Williams, Patricia J. Langhorne, Daniel P. Costa, Kimberly T. Goetz |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
0106 biological sciences
geography Leptonychotes weddellii geography.geographical_feature_category Offset (computer science) 010504 meteorology & atmospheric sciences biology 010604 marine biology & hydrobiology Aquatic Science Oceanography Geodesy biology.organism_classification 01 natural sciences Latitude Salinity Water column Data logger Sea ice thickness Sea ice Ecology Evolution Behavior and Systematics Geology 0105 earth and related environmental sciences |
| Zdroj: | Journal of Marine Systems. 187:250-259 |
| ISSN: | 0924-7963 |
| Popis: | The high-latitude oceans surrounding Antarctica are substantially undersampled compared to lower latitudes. Mammal based instruments such as Conductivity-Temperature-Depth Satellite Relay Data Loggers (CTD-SRDLs) present one possible solution. Unfortunately, these are subject to instrument-dependent offsets in absolute salinity. This study investigates a set of satellite-transmitted data collected by CTD-SRDLs mounted on Weddell seals (Leptonychotes weddellii) in the South-western Ross Sea in 2011. The uncorrected salinity offset between devices was found to be up to 1.4 g kg−1, making the data unsuitable for some oceanographic studies without correction. Here, a correction method was developed that uses profiles from pairs of CTD-SRDLs that are considered to be co-located and to sample the same body of water if they occur within defined time and space windows. Using least squares, a best-fit solution to the matrix of offsets in co-located pairs was found that reduces salinity offsets between the CTD-SRDLs. These offsets are smaller than the original offsets by a factor of 10. A calibrated reference instrument, that was co-located with some of the devices, provided further improvement in the absolute accuracy of all the CTD-SRDLs. Using the corrected CTD-SRDL data we estimate the rejection of salt into the water column by sea ice formation, and derived the time evolution of sea ice thickness in the South-western Ross Sea. Our estimates of regional sea ice thickness are in agreement with direct sea ice thickness measurements taken over a limited area in November 2011, providing further affirmation of our method. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect