Probability Distribution of Extreme Events in a Baroclinic Wave Laboratory Experiment
Round 1
Reviewer 1 Report
Comments on “Probability Distribution of Extreme Events in a BaroclinicWave
Laboratory Experiment” by Uwe Harlander , Ion Dan Borcia, Miklos Vincze 2, and Costanza Rodda
This is a nice short paper based on the lab. experiment with a classical setup. The statistical results on extreme events are compared with those for the atmosphere and good qualitative agreement was found. This shows that the experiment exhibits similar main physics to that of the large-scale atmospheric circulation. I recommend publication. I only found a couple of minor issues:
1. Figs 4 and 5. Please give units for mean and var.
2. Line 118. Misprint Fort -> For
Author Response
The authors: We thank the reviewer for the positive assessment and the constructive comments. We respond to the comments point by point.
This is a nice short paper based on the lab. experiment with a classical setup. The statistical results on extreme events are compared with those for the atmosphere and good qualitative agreement was found. This shows that the experiment exhibits similar main physics to that of the large-scale atmospheric circulation. I recommend publication. I only found a couple of minor issues:
Comment: Figs 4 and 5. Please give units for mean and var.
Response: In the revised version, the units for mean and variance are given in the figure caption.
Comment: Line 118. Misprint Fort -> For
Response: Corrected.
Reviewer 2 Report
Page 2, Figure 1. The image on the left and right have already been featured in the literature. Why are there no references?
Page 4, Table 2. Please do not change the temperature unit. Previously, Kelvin was used, not degrees Celsius.
Page 4, Table 2. What does NTSC mean? Is it the National Television System Committee?
Page 5, Figure 3. Why are the axis titles not added as in Figure 4?
Page 7, Figure 6."Left column, experiment; right column, NCEP data." Why are the marks (a) and (b) above the figure?
Author Response
The authors: We thank the reviewer for the positive assessment and the constructive comments. We respond to the comments point by point.
Comment: Page 2, Figure 1. The image on the left and right have already been featured in the literature. Why are there no references?
Response: In the revised manuscript references are given.
Comment: Page 4, Table 2. Please do not change the temperature unit. Previously, Kelvin was used, not degrees Celsius.
Response: In the revised version we use Kelvin in the table.
Comment: Page 4, Table 2. What does NTSC mean? Is it the National Television System Committee?
Response: NTSC is an abbreviation for “National Television Standards Committee”. It is a video format standard (besides the PAL, and SECAM video format). In the revised manuscript we removed it from the table since it is not relevant for the reader.
Comment: Page 5, Figure 3. Why are the axis titles not added as in Figure 4?
Response: In the revised manuscript version we added the axis labels to Figure 3.
Comment: Page 7, Figure 6."Left column, experiment; right column, NCEP data." Why are the marks (a) and (b) above the figure?
Response: It means that “Figure 6 (a)” shows the experiment and “Figure 6 (b)” shows the NCEP data.
Reviewer 3 Report
This paper compares the probability distribution of extreme events in a laboratory experiments to those occurring in the atmosphere. The topic is interesting & relevant and I am therefore happy to recommend publication subject to the following minor modifications.
- The authors should explain how the cylindrical annulus geometry of the experiments is likely to be a good model for a spherical shell atmosphere.
- The authors should explain whether the results are sensitive to the size of the sector used in Figure 3 for example.
- Page 1: the statement “Temperature control was rather easy … large number of researchers” needs to be substantiated with references.
- Page 1: Taylor number is referred to before it is actually defined.
- Page 1: Explain the symbols involved in the definition of the Rossby and Taylor number.
- Page 2: It is poor practice to start a sentence with a reference, i.e. [21] experimentally investigated … would be much better as The authors of [21] …
- Page 2: Is Ta = 3x10^{31} correct? This seems extremely high.
- Page 2: the statement “However, empirical experience in the laboratory justifies this approach” needs to be supported by a reference.
- Page 3, Figure 2: What is the color code for surface temperature?
- What is E_i in eq. (2)
- Page 5, figure 4: what are the units of the mean & variance?
Author Response
The authors: We thank the reviewer for the positive assessment and the constructive comments. We respond to the comments point by point.
This paper compares the probability distribution of extreme events in a laboratory experiments to those occurring in the atmosphere. The topic is interesting & relevant and I am therefore happy to recommend publication subject to the following minor modifications.
Comment: The authors should explain how the cylindrical annulus geometry of the experiments is likely to be a good model for a spherical shell atmosphere.
Response: In the revised manuscript we give an argument why the cylindrical geometry can capture the essential dynamics of baroclinic wave and jet formation (see blue text at the beginning of the conclusion section). In fact, we are planning experiments for the near future that include some part of the beta-effect by using a sloping bottom. However, presently we started by using the simplest setup for the experiment.
Comment: The authors should explain whether the results are sensitive to the size of the sector used in Figure 3 for example.
Response: We added a note on page 4 (blue text). It is relevant to minimize topographic effects that are absent in the experiment. However, corresponding sectors over other oceans do not alter the statistical results significantly.
Comment: Page 1: the statement “Temperature control was rather easy … large number of researchers” needs to be substantiated with references.
Response: We included the reference of two review articles with many references to support our claim.
Comment: Page 1: Taylor number is referred to before it is actually defined.
Response: To solve this we now give a link to equation (1).
Comment: Page 1: Explain the symbols involved in the definition of the Rossby and Taylor number.
Response: As said in the text, all the symbols are explained in table 1.
Comment: Page 2: It is poor practice to start a sentence with a reference, i.e. [21] experimentally investigated … would be much better as The authors of [21] …
Response: We agree and have corrected this.
Comment: Page 2: Is Ta = 3x10^{31} correct? This seems extremely high.
Response: We used the following numbers for estimating the Taylor number for the Earth atmosphere:
a=10^6m; b=6*10^6m; d=10^4m; Omeg=7.2921e-05rad/s; nu=15.11*10^(-6)m^2/s;
The Taylor number is so large since L=b-a is a large number (6x10^6m) and goes with an exponent of 5 in the definition of the Taylor number. At the same time d is rather small (10km). Of course, the meaning for a Taylor number of the Earth atmosphere using equation (1) is not straightforward. In the revised manuscript we added a short comment (blue text).
Comment: Page 2: the statement “However, empirical experience in the laboratory justifies this approach” needs to be supported by a reference.
Response: We added a reference supporting this view.
Comment: Page 3, Figure 2: What is the color code for surface temperature?
Response: We added the numbers for the color code in the figure caption.
Comment: What is E_i in eq. (2)
Response: $E_i$ is the spatial mean and $V_i$ the spatial variance for each day (i.e. once per revolution) $i=1,2,...,2880$ of the series of IR-images. The definition is given on page 4 and highlighted in blue.
Comment: Page 5, figure 4: what are the units of the mean & variance?
Response: In the revised manuscript we give the units Kelvin (K) and K^2 in the figure caption.
Reviewer 4 Report
This article presents the investigation of the probability distribution of extreme events for Atmospüheric dynamics. The investigation has been done using lab equipment, a Baroclinic Wave Laboratory Experiment, where differentially heated rotating annulus, has provided insight into the dynamics of the streams.
Th tequinique is used to simulate the interaction of a temperature gradient with the flow in rotating domains and has been proven to be representative of describing the atmosphere dinamics.
In this article probability density distributions of extreme events from a longterm laboratory experiment are studied and compared to the measured atmospheric probability density distributions.
The article is clear and well written with good language. Figures and derivation are clear and the reader can understand clearly the conclusions from the data elaborated.
Author Response
This article presents the investigation of the probability distribution of extreme events for Atmospheric dynamics. The investigation has been done using lab equipment, a Baroclinic Wave Laboratory Experiment, where differentially heated rotating annulus has provided insight into the dynamics of the streams.
The technique is used to simulate the interaction of a temperature gradient with the flow in rotating domains and has been proven to be representative of describing the atmosphere dynamics.
In this article probability density distributions of extreme events from a longterm laboratory experiment are studied and compared to the measured atmospheric probability density distributions.
The article is clear and well written with good language. Figures and derivation are clear and the reader can understand clearly the conclusions from the data elaborated.
The authors: We thank the reviewer for the very positive assessment.
