Response of water temperatures and stratification to changing climate in three lakes with different morphometry

Magee, Madeline R.; Wu, Chin H.

doi:https://doi.org/10.5194/hess-21-6253-2017

Articles | Volume 21, issue 12

https://doi.org/10.5194/hess-21-6253-2017

© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.

https://doi.org/10.5194/hess-21-6253-2017

© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.

Articles | Volume 21, issue 12

Research article

|

11 Dec 2017

Research article |

| 11 Dec 2017

Response of water temperatures and stratification to changing climate in three lakes with different morphometry

Madeline R. Magee and Chin H. Wu

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Final revised paper (published on 11 Dec 2017)
Preprint (discussion started on 26 Jul 2016)

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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- Supplement

RC1: 'Reviewer comments to the MS by Magee & Wu', Anonymous Referee #1, 28 Aug 2016
- AC1: 'Response to Reviewer 1', Chin Wu, 19 Oct 2016
RC2: 'Review on ``Response of water temperatures and stratification to changing climate in three lakes with different morphometry'' by Magee and Wu', Anonymous Referee #2, 01 Sep 2016
- AC2: 'Response to Reviewer 2', Chin Wu, 19 Oct 2016

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

ED: Reconsider after major revisions (further review by Editor and Referees) (19 Oct 2016) by Jan Seibert

AR by Chin Wu on behalf of the Authors (28 Dec 2016) Author's response Manuscript

ED: Referee Nomination & Report Request started (30 Dec 2016) by Jan Seibert

RR by Anonymous Referee #3 (16 Mar 2017)

Suggestions for revision or reasons for rejection

Review of Magee and Wu, “Response of Water Temperatures … different morphometry”.

This paper consists of a sensitivity study of three lakes in the Madison area to changes in meteorological forcing, and compares the responses to these changes among these three lakes utilizing some fairly standard metrics like phenology, max/mean temperatures and stability metrics. I think it could be published, but I’m not entirely convinced of its originality and I have some comments about methodology as well. If the paper is to be revised, they need to do a better job of distinguishing this from the many other papers out there that discuss this sort of sensitivity analysis.

My main methodological concern with this paper is that it attempts to look at the role that lake area has on the response to changes in meteorological conditions, but uses a 1-dimensional model to do so. They include an empirical adjustment to account for lake area, but it seems to me that at this stage, you’re not looking at the response dependence on lake area, you’re looking at the response dependence on an empirical lake area adjustment. Why not just use a 3D model? Computing is cheap these days.

One result I found very strange is their description of the “nonlinear” response of some of the lakes to various perturbations. They state that the response depends on whether they are perturbing, for instance, air temperature in the positive direction or negative direction (p12. Lines 10-15, again lines 20-25). There’s nothing special about the base case, so the division they point out is artificial.

If they are going to discuss step changes in various parameters, they should probably reference the van Cleave and Lenters paper that does this for Lake Superior.

On a more minor note, they should specify what bulk turbulence method they are using in the model.

I was confused by the statement “all parameters and coefficients are kept constant” (p. 5 line 26). What parameters are these?

Do they use the same sediment temperature model for all three lakes? Is this justified?

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RR by Anonymous Referee #4 (16 Apr 2017)

Suggestions for revision or reasons for rejection

Review of ‘Response of water temperatures and stratification to changing climate in three lakes with different morphometry’ by Magee and Wu

General comments
This is a well written paper describing an interesting topic in climatology and limnology: ‘How has lake temperature and stratification responded to a changing climate, and how can we expect these responses to differ among lakes’. Magee and Wu use an exceptional dataset of >100 years and focus on the effects of changing air temperature and wind speed on water temperature and stratification patterns in three lakes situated near Madison, Wisconsin (US), which are characterized by different morphometric features. Similar results have been presented in the literature for lakes elsewhere (see specific details below), but the strengths of this paper is the across-lake comparison and the use of a one-dimensional lake model to disentangle the different factors which contribute to a lakes response to climate change. The authors use the one-dimensional lake model (DYRESM-WQ), which has been used frequently by the limnological community during the past 20 or so years. I must admit, I am not a fan of using models that are not openly available (this is my understanding of DYRESM), especially as many other one-dimensional lake temperature models are openly available to the community. For example, the General Lake Model (GLM), Freshwater Lake model (FLake), and MyLake all have similar capabilities to DYRESM but are open-access. If my understanding is incorrect and DYRESM is openly available, please state this in the methods. The authors use DYRESM to reconstruct the thermal and stratification regime of the lakes during the last century and for sensitivity studies exploring the lake responses to changes in mean annual air temperature and wind speed.
I found the aim of this paper clearly described, the results very convincing and presented in a reasonable manner, and I think the paper will be well received by the limnological community. Specifically, this paper investigates what, in my opinion, is currently lacking in the scientific literature. Specifically, many of the previous studies that have examined the response of lake surface water temperature to climate change have focused on the past few decades. Thus, having a study focusing on lake temperature responses from the start of the 20th century is an important contribution. I do believe this is an important topic, and one that deserves some attention - particularly given the recent emphasis on the rapid warming of lakes from around the world, and the numerous ecological and socioeconomic consequences of increase lake surface water temperature, in addition to their interactions within the climate system.
Overall, I think this paper is well written, the data is well chosen and the analysis is reasonable. I can see this paper being a benchmark for future studies and an important contribution to the literature. I think there is great potential for this paper to be valuable to the community.

Specific Comments

Introduction
In general, the introduction is well written. However, the literature review seems rather limited and many of the recent studies covering this topic have been overlooked. For example, see the O’Reilly et al. (2015) paper and references therein for an update of some recent paper in this topic. Also, in the opening paragraph, the authors refer to decreasing wind speeds but not referred to some of the important papers in this topic, such as Vautard et al. (2010) who demonstrated that wind speeds globally have been decreasing. In addition, of great relevance to the current study is the paper by Woolway et al. (2017a) who followed a very similar approach to that described in this paper when reconstructing the thermal dynamics of Vortsjarv (Estonia) - they also investigated the response of lake temperature dynamics to changes in air temperature and wind speed.

P2L15 - Lake water temperature is closely related to the… Equally important is humidity, cloud cover, solar radiation - in particular the surface energy fluxes. For example, the study of Schmid and Köster (2016) demonstrated that 60% of lake surface water temperature warming in Lake Zurich was caused by air temperature and 40% by increased solar radiation. Also, a paper by Wilhelm et al. (2006) demonstrated that daily extreme water temperatures (although they used the equilibrium temperature) responded to shifts in air temperature, wind speed, relative humidity, and cloud cover. Thus, one could argue that to understand fully how lake surface water temperatures will respond to climate change, one would require each of these variables to be included. This has been shown to be important for some lakes (Schmid and Köster 2016). I realize that the authors have likely considered all of the points I’ve raised here, but I think they should be mentioned in the paper.

Also, important is local features. For example, the study Tanentzap et al. (2008) showed that some lakes might cool as air temperatures increase, as a response of the complicated interactions between lakes and their environment and/or internal processes.

…found that decreasing wind speeds resulted in increased stratification… - This is a great example of the Woolway et al. (2017a) study.

In terms of the influence of lake surface area altering the response of lakes to atmospheric forcing, I think more context is needed here. Specifically, numerous papers have demonstrated the importance of lake size, some of which you already cited. Some examples:

• Winslow et al. (2015), which you cite, demonstrated that small lakes demonstrate a muted response of deep water temperature to climate change.
• Read et al. (2012) demonstrated that lake size influences the relative contribution of wind and convective mixing to the gas transfer coefficient in lakes.
• Woolway et al. (2016) demonstrated that lake size can influence the magnitude of diurnal heating and cooling in lakes which has important consequences for gas transfer (Holgerson et al. 2017).
• Torbick et al. (2016) demonstrates that smaller lakes in northeast United States have been warming more rapidly than larger lakes in terms of surface water temperature.

Note I only list a few above but there are many others, which I trust the authors to find.

Methods
Is DYRESM-WQ open-access? If so, I think details of where the reader can find the source code would be useful. Similar to GLM (General Lake Model), which is openly available, I would hope DYRESM-WQ is available to the community, as all results should be reproducible by the reader.

I would show the light attenuation coefficient as Kd (not k), as it is commonly referred in the limnological community.

Discussion
This paper has some similarities with a paper very recently published in Climatic Change by Woolway et al. (2017b). In particular, they also analyze a > 100 year lake temperature time series from two lakes in Austria (Mondsee and Worthersee), and investigate how 20 lakes with >50 years of observations have responded to climatic warming. I would strongly encourage the authors to discuss these results and compare to their findings. In addition, how do the abrupt shifts, which you discuss (evaluated via the Rodionov method), compare with Woolway et al. (2017b)?

Figures and Tables
Figure 1: Can the authors add a local map to illustrate how close these lakes are to one-another? I know this is mentioned in the text, but including a map would be useful. Also, it is rather difficult to see some of the contour values. If the contours can be re-drawn in grey, that would make the writing more understandable - or potentially redraw these as colour plot, if you are generating figures in colour.

Figure 2. Interestingly, the step in annual air temperature seems to occur at the same time as reported by Woolway et al. (2017b) for Central Europe, a result of a global shift perhaps? Also, the wind speed change in ~1995 is consistent with the results of Woolway et al. (2017a) for Estonia, although they do not report on the exact year, but a shift can be seen from their figures.

References:

Bichet A, Wild M, Folini S, Schär C (2012) Causes for decadal variations of wind speed over land: Sensitivity studies with a global climate model. Geophys Res Lett 39(11). doi:10.1029/2012GL051685.

Holgerson M, Farr E, Raymond P (2017) Gas transfer velocities in small forested ponds. J. Geophys Res. doi: 10.1002/2016JG003734

O’Reilly et al. (2015) Rapid and highly variable warming of lake surface waters around the world. Geophy Res Lett 42, 10773-10781.

Schmid M, Köster O (2016) Excess warming of a Central European lake by solar brightening. Water Resour Res 52:8103-8116. doi:10.1002/2016WR018651

Tanentzap AJ, et al. (2008) Cooling lakes while the world warms: Effects of forest regrowth and increased dissolved organic matter on the thermal regime of a temperate, urban lake. Limnol Oceanogr 53:404-410.

Torbick et al. (2016) demonstrates that smaller lakes in northeast United States have been warming more rapidly than larger lakes in terms of surface water temperature.

Vautard R, Cattiaux J, Yiou P, Thepaut J, Ciais P (2010) Northern Hemisphere atmospheric stilling partly attributed to an increase in surface roughness. Nature Geo Sci 3:756-761.

Wilhelm S, Hintze T, Livingstone DM, Adrian R (2006) Long-term response of daily epilimnetic temperature extrema to climate forcing. Can J Fish Aquat Sci 63:2467-2477.

Woolway, R.I., Jones, I.D., Maberly, S.C. et al. (2016). Diel surface temperature range scales with lake size. PLoS One 11(3): e0152466. doi: 10.1371/journal.pone.0152466

Woolway, R.I., Meinson, P., Nõges, P., Jones, I. D., Laas, A. (2017a). Atmospheric stilling leads to prolonged thermal stratification in a large shallow polymictic lake. Climatic Change. doi:10.1007/s10584-017-1909-0

Woolway, R.I., Dokulil, M., Marszelewski, W., Schmid, M., Bouffard, D., Merchant, C.J. (2017b). Warming of Central European lakes and their response to the 1980s climate regime shift. Climatic Change. doi:10.1007/s10584-017-1966-4

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ED: Publish subject to revisions (further review by Editor and Referees) (01 May 2017) by Jan Seibert

AR by Chin Wu on behalf of the Authors (15 Jun 2017) Author's response Manuscript

ED: Referee Nomination & Report Request started (26 Jun 2017) by Jan Seibert

RR by Anonymous Referee #5 (03 Oct 2017)

ED: Publish subject to minor revisions (further review by Editor) (03 Oct 2017) by Jan Seibert

AR by Chin Wu on behalf of the Authors (13 Oct 2017) Author's response Manuscript

ED: Publish as is (02 Nov 2017) by Jan Seibert

AR by Chin Wu on behalf of the Authors (07 Nov 2017)

Short summary

Water temperatures and stratification in three morphometrically different lakes over the century are examined. Simulations showed that epilimnetic temperatures increased, hypolimnetic temperatures decreased, the length of the stratified season increased due to earlier stratification onset and later fall overturn, and stability increased. Results showed that wind speed has a large effect on temperature and stratification variables, sometimes greater than changes in air temperature.