|In the present paper, WRF-CHEM numerical model is used to evaluate the feedback of aerosols, mainly originated as sea salt aerosols (SSA), in the development of three Medicanes. To this end, simulations have been performed with interactive aerosol concentrations (IA) instead of prescribing aerosols (PA). The results indicate that IA produces longer-lasting and more intense Medicanes than PA. The role of nudging is also explored to show that it generally produces longer but less intense cyclones.|
Although the paper has improved compared to the previous version, I do not consider it yet at sufficient level for publication in a journal with high impact factor, such as ACP.
1)The introduction still suffers from several problems.
- The Introduction is very short and should contain some additional paragraphs on aerosol-cloud interactions.
- Some sentences are still incorrect or are not clear:
Line 27: There is still no consensus on the definition of medicanes. Following the most accepted definition, the WISHE mechanism is only one possible way of development that some medicanes follow. There is no evidence that “medicanes are generally maintained as tropical cyclones”. Conversely, if you consider as medicanes only those with tropical mechanisms of development, you should change “generally” with “always”. But you should elaborate more on this point and provide the definition you are considering.
Line 28: When you write about the advection of warm and moist air toward the low pressure center, I think of baroclinic cyclones (in the warm sector), not of tropical cyclones, where advection is secondary compared to sea surface fluxes and latent heat release. For tropical cyclones, the WISHE mechanism is effective, as you explain a few lines later.
Line 48: please explain in which way aerosols may affect medicane genesis. I expect that they may affect their development, but not their formation.
Line 50: “special”: the cyclogenetic mechanism of medicanes is the same as that of baroclinic cyclones (medicanes originate as extratropical cyclones), but the evolution is different. Does “special” refer to the particular atmospheric conditions in which these cyclones form (see Cavicchia et al., 2014)?
Line 50-52: the sentence on the high influence of initial conditions is true also for extra-tropical cyclones, not only for medicanes (e.g., Doyle et al., 2013: Initial Condition Sensitivity and Predictability of a Severe Extratropical Cyclone Using a Moist Adjoint, and related bibliography).
2)I have to repeat what I mentioned in the review of the previous version: spectral nudging (as your runs confirm) is not appropriate for individual case studies, since the dynamics are not allowed to make the cyclone evolve freely (without constraints) within the domain, affecting negatively the simulation in terms of cyclone intensification, but it is appropriate for downscaling of global climate models. You can read more about how to use FDDA in WRF in the slide 2 of the presentation by the developer of FDDA, dr. Jimy Dudhia (NCAR), that you can find at https://vdocuments.mx/wrf-four-dimensional-data-assimilation-fdda-jimy-dudhia.html3).
The lower two rows in Fig. 2 are nearly identical: this clearly shows, as expected, that the nudging strongly controls the cyclone tracks. Since it reduces the role of internal model physics in the simulation of the cyclone, also the treatment of aerosols has no longer a significant impact on the cyclone simulation.
3)Following Kudryavtsev and Makin (2011), Liu et al. (2012), Rizza et al. (2021), the so-called spume droplets, which have radii in the approximate range [20–500] μm, are not relevant for CCN, as you correctly mention, but they are important to consider as they can significantly modify the roughness for high wind speed, such as those typical of medicanes. Thus, to make your work complete, you should include this modification as well, or at least take into consideration this significant limitation.
4)The methodology used to define the TITAN algorithm is not clear:
Line 206: what do you mean with “cyclonic potential field?”
Line 207: why do you use the odd unit of rad h-1 for vorticity?
Line 209-210: what do you mean with “5 minimum points in a cluster”?
Line 210: why do you set the threshold of B to 20 m instead of the usual value of 10 m?
Line 210-211: what do you mean with “the lower and upper tropospheric thermal wind parameters calculated in the 900-600 hPa and 600-300 hPa layers”, without any indication on the value they should take?
Line 212: what do you mean with “zero vorticity radius”? the minimum? the maximum? the average in the four directions?
Line 19: the presence of environmental wind shear at mid-latitudes should also be mentioned.
Line 25: … early development …
Line 29: potential instability instead of convection
Line 37: … paid to …
Line 41: … plays …
Line 43-44: please rephrase as: “Hence, the use of an appropriate microphysics parameterization, along with the explicit solving of aerosols, seems to be fundamental for the development of the medicanes in the model simulations”.
Line 44: … insight into …
Line 79: degree is not necessary and can be removed
Line 107: the datasets come from WRF users’ webpage, but there are several datasets available: which one do you use?
Line 117: grid spacing is correct; resolution has a different meaning (see Skamarock, 2004)
Line 168: Are you sure the alignment anticipates the occurrence of tropical features by one day? According to their typical mechanisms of development, they should be nearly simultaneous.
Line 173: please provide a reference to indicate where this data are provided!
Line 177: … large compact …: are not the two adjectives contradicting?
Line 177: … approached Greece …
Line 180-181: it seems like the medicane and the initial low are two different systems: is it true?
Line 188, Line 190: 0600 UTC.
Figure 1: I could hardly identify the grey boxes in Fig. 1.
Line 232: How is K_H defined?
Line 248: generally instead of systematically
Line 253: separated by 1 day
Line 270: are instead of is
Figure 2: color scale is missing
Line 309: to resemble the large scale …
Line 307-315: your explanation addresses why a more intense medicane formed in the IA runs, but not why it is longer-lasting
Line 321: what do you mean with “when it comes to medicanes”?
Line 324: because of …
Line 325: the most similar …
Line 325-326: do you mean that they are very close in terms of track? Otherwise, what is their similarity considering that the intensity is different?
Figure 5 caption: the blue marks refer to times when the medicane structure is lost: in which simulations? In both?
Figure 5: I do not understand the choice of considering the structure along the vertical of the medicane center, and not as average over a region around it, considering that this is the area where the eye is present, and obviously cannot be representative of the conditions conducive to convection;
Figure 6 caption: what do you mean with “time-averaged”? are you considering only the times when a medicane is detected?
Figure 6 caption: What do you mean with “in-level anomaly of potential temperature”?
Line 338: are you sure that you can see the “divergence of the warm air aloft”? or is it just the increased equivalent potential temperature with height that you can find everywhere in the domain near the tropopause?
Line 349: height-radius is more appropriate than height-longitude;
Line 352: Figure 7 shows ...
Line 402: their own …
Cavicchia, L., H. von Storch, and S. Gualdi, 2014: A long-term climatology of medicanes. Climate Dyn., 43, 1183–1195, doi:10.1007/s00382-013-1893-7.
Doyle, J. D., C. Amerault, C. A. Reynolds, and P. A. Reinecke, 2014: Initial condition sensitivity and predictability of a severe ex- tratropical cyclone using a moist adjoint. Mon. Wea. Rev., 142, 320–342, https://doi.org/10.1175/MWR-D-13-00201.1.
Kudryavtsev, V.N., Makin, V.H., 2011. Impact of ocean spray on the dynamics of the marine atmospheric boundary layer. Boundary-Layer Meteorol. 140, 383–410. https://doi.org/10.1007/s10546-011-9624-2.
Liu, B., Guan, C., Xie, L., Zhao, D., 2012. An investigation of the effects of wave state and sea spray on an idealized typhoon using an air–sea coupled modeling system. Adv. Atmos. Sci. 29, 391–406.
Skamarock, W. C., 2004: Evaluating mesoscale NWP models using kinetic energy spectra. Monthly Weather Review, 132, 3019-3032.