sunRunner1D: A Tool for Exploring ICME Evolution through the Inner Heliosphere

Round 1

Reviewer 1 Report

The paper discusses a one-dimensional model for estimating CMEs in order to predict the parameters of the space model. The authors considered several events. By selecting initial conditions, the authors reproduce the properties of these ICMEs with varying degrees of success. The work can be published after the comments have been eliminated.

 

1. The authors claim that they have developed a tool that can be useful in predicting CW. However, in the proposed scheme, the authors change the boundary conditions, achieving coincidence with the measured parameters of the CME near the Earth's orbit. Often these boundary conditions do not look plausible. How such a method can help in real forecasts.

 

2. It is not entirely clear from the description that data on the undisturbed solar wind (speed, temperature, magnetic field) were used as parameters along which the CME propagates. Also, high-speed  SW streams that have flown out after the CME can catch up and affect the spread of the CME. These parameters can be obtained using the WSA model and, for example, the ballistic model. The authors write in section 2.3 that “In all cases, we focused on the main parameters of the solar wind, including speed, quantity density, temperature and magnetic field strength." But in Fig. 3 and 5 there is no inhomogeneity in the radius.

 

3. If the parameters of the undisturbed SW are not set and do not change in the model, then why is this done. Do the authors consider the background SW to be insignificant for the distribution of CME.

 

4. In Table 2, the parameters are given up to the seventh digit. Why is this done. Probably such accuracy is much less than the accuracy of measurements. How critical is the model to the choice of initial conditions.

 

5. For event 1, the authors assume the eruption of 2 prominences. But in Fig. 3, one pulse is visible for the boundary conditions. How to explain it.

 

6. For Event 1, the temperature at STEREO-A is calculated to be 50 MK. This is significantly more than the estimates made earlier (Fig. 1). It is unclear why the calculated temperature is so high, and other parameters, such as velocity and density, roughly coincide with the measurements. Does this mean that the model is not applicable for this event.

 

7. For event 2, the initial boundary temperature at the Sun is 5 MK. It seems that this value is redundant. How it can be explained.

 

7. Для события 2 начальная граничная температура на Солнце равна 5 МК. Кажется, что это значение избыточно. Как это можно объяснить.

 

8. In Fig. 8, the temperature at a distance from the Sun at the moment t = 0 is also visible excess temperature. This error is probably related to the initial conditions. This can also be seen in the speed.

 

9. In general, when comparing different events with measurements, it can be seen that the model describes the parameters on the F shock wave quite well. But in the above measurements, the existence of an R shock wave is almost not visible. Perhaps the authors should insert a discussion of this discrepancy into the discussion. Is this a disadvantage property of the chosen one-dimensional model.

 

 

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

The topic of the paper is relevant, and it is well written. The work is nice and useful to readers. I saw only one rather serious problem in it. And even then, I, as a reader, am ready to share the blame for it with the authors. However, I fear that some other readers, on the basis of the title and abstract, will expect even more from this meaningful work than it contains. Perhaps small changes in the title and the end of the abstract will allow future readers to experience only positive emotions, which will not be mixed with slight disappointment. The promised tool actually exists. It is good enough to help researchers better understand the changes in ICME as it propagates through the inner heliosphere. However, those who try to use this tool in space weather forecasting are unlikely to find it easy-to-use and fairly reliable. The authors understand this better than me. To their credit, they don't just pick winning examples and don't hide problems. I hope that with the further development of the proposed approach, forecasters will receive a useful tool. But a future possible article presenting such a tool will look different. There will be more events, more attention paid to error estimates, more references to other works, and so on. In the meantime, we have already a fundamental study, performed and presented at a high level.

 Below are also a couple of minor notes:

 The text mentions plots a, b, c, but these letters are not on the figures themselves.

It is not clear why there are such large times in Figure 2.

 

 

After minor revision the paper can be published.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 3 Report

The manuscript “sunRunner1D: A tool for Exploring ICME Evolution through the

Inner Heliosphere” introduce a new tool, sunRunner1D, that is a compromise for simple empirically algorithm and complex 3D MHD simulations to reproduce the structure and evolution of CMEs from the solar corona to 1 AU. The sunRunner1D can be easily run by novice users with only modest computational resources. The authors demonstrated that this tool can effectively reproduce the essential properties of four cases of ICMEs, and suggested that this tool can be helpful in predicting the time of arrival (ToA) and geomagnetic consequences of ICMEs. 

 

The paper is well written, and there is only some minor suggestions.

 

First, the usage of abbreviations. For example, ToA and MHD.

Line 4: “arrival time” à “time-of-arrival” 

Line 41: “time-of-arrival” à”time-of-arrival (ToA)” 

Line 375-376: “time of arrival”à “ToA”

Line 402-403: “time-of-arrival (ToA)”à “ToA”.

Line 18: “MHD” à ”magnetohydrodynamic (MHD)”.

Line 29: “magnetohydrodynamic (MHD)” à “MHD”.

 

Second, the curves of solar wind parameters as the function of time in Figures 1, 6, 9, 11.

For a better comparison, all in situ measurements can be shown by black curves, and the model results can be drawn in another color (red).

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The authors took into account the comments and made corrections and clarifications to the article.