Correction to “Tracing the upper ocean's ‘missing heat’”
This article corrects:
- Tracing the upper ocean's “missing heat” Volume 38, Issue 14, Article first published online: 30 July 2011
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 In the paper “Tracing the upper ocean's ‘missing heat’” by C. A. Katsman and G. J. van Oldenborgh (Geophysical Research Letters, 38, L14610, doi:10.1029/2011GL048417, 2011), there is an error in one computation. Colleagues brought this error to our attention. In the paper, we present modeled distributions of 8-yr trends in upper ocean heat content (UOHC) for the periods with central years ranging from 1969–1999 (Figure 2a) and for the period 1990–2020 (Figure 2b). In these figures, 11% and 3% of the distribution consists of zero or negative trend values, respectively.
 In converting this percentage of running 8-yr periods with no increase in UOHC into the probability that one or more of these events would occur, we inadvertently used a formula that assumed the 8-yr trends were independent. This is obviously not the case, as the periods are overlapping.
2. Corrected Results
 We have recomputed the probability in two ways. The first was simply counting the number of ensemble members that show a negative trend in these years. The second method consists of estimating the decorrelation time Td by the lag at which the autocorrelation of the time series of 8-yr trends is 1/e and defining the number of degrees of freedom D = N/Td, with N = 31 years is the length of the considered time period. The probability P of an 8-yr period without an increase in UOHC is then calculated from P = 1 − (1 − p)D with p the probability of a negative trend value derived from the distributions displayed in Figure 2 of the paper.
 For the 8-yr trends, the decorrelation time Td is about 3 years, so that D ≈ 10. For the historical period 1969–1999 both methods give a 65% chance of one or more 8-yr periods with a negative trend, rather than the 97% chance mentioned in the caption of Figure 2. For the 1990–2020 period the estimates are 25–30% rather then the reported 57% (Section 3, caption of Figure 2).
 Section 4 of the auxiliary material contains a similar computational error with regard to the distribution of 9-yr trends. For this case, we calculated that Td ≈ 3.5 years, so D ≈ 9 degrees of freedom. The distribution of 9-yr trends has 2.1% negative trends in UOHC for 1990–2020, and 0.4% for 2000–2030. The corrected calculation yields a 5–15% probability of at least one period with a 9-yr negative trend occurring in 1990–2020 and 0–5% in 2000–2030, rather than the reported 48% and 11%.
 Despite the computational error, the statement that “the analysis reveals that an 8-yr period without upper ocean warming is not exceptional” in the abstract of Katsman and van Oldenborgh  remains valid.
 The computational error has no impact at all on the analysis in the remainder of the paper, from which we concluded that such a period without upper ocean warming is explained by increased radiation to space, largely as a result of El Niño variability on decadal timescales, and by increased ocean warming at larger depths, partly due to a decrease in the strength of the Atlantic meridional overturning circulation.