28 / 59
Ref. No. [UMCES] CBL 2016-015
ACT VS16-06
28
Figure L.
Assessment of the sensor response time for the EXO2 Sonde with Optical DO (sn 14J103998).
Top Panel
: Time series of 10s reads of instruments during transfers between high and low DO buckets
maintained adjacent in a common water bath equilibrated at 15
o
C. Indicated DO levels were maintained by
airstone bubblers (high DO) or air+N2 (low DO) and verified by Winkler assays.
Bottom Panels
: All high
DO to low DO transitions were normalized to last reading before condition switch for the indicated time
post transition (left). Data was fit with a 3 parameter exponential decay function: DO
rel
= DO
relMin
+ a
e
-bt
and indicated τ calculated from fit. Data for low DO to high DO transitions (
lower right
) were treated
similarly but normalized to steady state value in subsequent high DO tank and subsequently fit with an
analogous 3 parameter exponential rise function: DO
rel
= DO
relMin
+ a(1-
e
-bt
) with indicated τ being directly
calculated from fit.