Sorry, you need to enable JavaScript to visit this website.

Investigation of XBT and XCTD biases in the Arabian Sea and the Bay of Bengal with implications for climate studies

TitleInvestigation of XBT and XCTD biases in the Arabian Sea and the Bay of Bengal with implications for climate studies
Publication TypeArticolo su Rivista peer-reviewed
Year of Publication2011
AuthorsBoyer, T., Gopalakrishna V.V., Reseghetti Franco, Naik A., Suneel V., Ravichandran M., Ali N.P. Mohammed, Rafeeq M.M. Mohammed, and R. Chico Anthony
JournalJournal of Atmospheric and Oceanic Technology
Volume28
Pagination266-286
ISSN07390572
KeywordsArabian Sea, Bay of Bengal, Climate change, Climate studies, Climate variability, climate variation, Climatology, Conductivity temperature depths, Correction of errors, CTD data, Data sets, Indian Ocean, Interannual, Long time series, marine atmosphere, Mean temperature, Probes, Rate equations, temperature anomaly, Temperature bias, Temperature changes, Temperature error, Time series, Velocity coefficients, Xbt datum
Abstract

Long time series of XBT data in the Bay of Bengal and the Arabian Sea are valuable datasets for exploring and understanding climate variability. However, such studies of interannual and longer-scale variability of temperature require an understanding, and, if possible, a correction of errors introduced by biases in the XBT and expendable conductivity-temperature-depth (XCTD) data. Two cruises in each basin were undertaken in 2008/09 on which series of tests of XBTs and XCTDs dropped simultaneously with CTD casts were performed. The XBT and XCTD depths were corrected by comparison with CTD data using a modification of an existing algorithm. Significant probe-to-probe fall-rate equation (FRE) velocity and deceleration coefficient variability was found within a cruise, as well as cruise-to-cruise variability. A small ( 0.01°C) temperature bias was also identified for XBTs on each cruise. No new FRE can be proposed for either the Bay of Bengal or the Arabian Sea for XBTs. For the more consistent XCTD, basin-specific FREs are possible for the Bay of Bengal, but not for the Arabian Sea. The XCTD FRE velocity coefficients are significantly higher than the XCTD manufacturers' FRE coefficient or those from previous tests, possibly resulting from the influence of temperature on XCTD FRE. Mean temperature anomalies versus a long-term mean climatology for XBT data using the present default FRE have a bias (which is positive for three cruises and negative for one cruise) compared to the mean temperature anomalies for CTD data. Some improvement is found when applying newly calculated cruise-specific FREs. This temperature error must be accounted for in any study of temperature change in the regions. © 2011 American Meteorological Society.

Notes

cited By 4

URLhttps://www.scopus.com/inward/record.uri?eid=2-s2.0-79953180080&doi=10.1175%2f2010JTECHO784.1&partnerID=40&md5=0955c11f931a3f78db2deb76eab0b64c
DOI10.1175/2010JTECHO784.1
Citation KeyBoyer2011266