Reply to comment by J. S. Selker et al. on “Capabilities and limitations of tracing spatial temperature patterns by fiber‐optic distributed temperature sensing”

Reply to comment by Francisco Suárez on “Capabilities and limitations of tracing spatial temperature patterns by fiber‐optic distributed temperature sensing”

“…We do not object at all to the first point of Su arez [2014], which also coincides with the suggestions provided in an earlier comment by Selker et al [2014]. As we already outlined in our response to Selker et al [2014], there is no doubt that FO-DTS field calibration can be further improved by using control baths covering both ends of the expected temperature spectrum [Krause et al, 2014]. We find it important though to reiterate that Rose et al [2013] did aim to quantify uncertainties arising from reported calibration designs of typical field application including the ones of the authors of the comment [e.g., Tyler et al, 2008Tyler et al, , 2009Briggs et al, 2012;Lutz et al, 2012;Krause et al, 2012].…”

“…The calibration reported by Su arez[2014] produced large errors in temperature measurements significantly warmer or colder than the calibration baths, independent from the spatial extent of the signals, while the decline of Water Resources Research PUBLICATIONS independent of cable section length, similar to the results of Su arez[2014]. As previously discussed inRose et al [2013] andKrause et al [2014], the faster decline in accuracy of warm signal detection with reducing signal size than for comparable cold signals, is likely to result from a larger difference to ambient temperatures than for cold bath temperatures and consequently larger relevance of enhanced edge effects at the signal margins.Su arez[2014] claims that ''a critical deterioration of quantitative accuracy of FO-DTS measured temperatures with reducing signal size claimed byRose et al [2013]'' cannot be fully supported by his own data. This assessment for his results is correct, considering that neither his calibration data seem to be satisfying with regard to capturing the full range of temperatures, nor did he actually investigate the impact of variable signal sizes.…”

“…As we already outlined in our response to Selker et al . [], there is no doubt that FO‐DTS field calibration can be further improved by using control baths covering both ends of the expected temperature spectrum [ Krause et al ., ]. We find it important though to reiterate that Rose et al .…”

“…[] and Krause et al . [], the faster decline in accuracy of warm signal detection with reducing signal size than for comparable cold signals, is likely to result from a larger difference to ambient temperatures than for cold bath temperatures and consequently larger relevance of enhanced edge effects at the signal margins.…”