the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
The impacts of dust aerosol and convective available potential energy on precipitation vertical structure in eastern China as seen from multiple source observations
- 1School of Earth and Space Science, Comparative Planetary Excellence Innovation Center, University of Science and Technology of China, Hefei 230026, China
- 2State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei 230026, China
- 3Institut de recherche sur les forêts, Université du Québec en Abitibi-Témiscamingue (UQAT), Rouyn-Noranda, J9X 5E4, Canada
- 1School of Earth and Space Science, Comparative Planetary Excellence Innovation Center, University of Science and Technology of China, Hefei 230026, China
- 2State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei 230026, China
- 3Institut de recherche sur les forêts, Université du Québec en Abitibi-Témiscamingue (UQAT), Rouyn-Noranda, J9X 5E4, Canada
Abstract. The potential impacts of dust aerosol and atmospheric convective available potential energy (CAPE) on the vertical development of precipitating clouds in eastern China were studied using multiple-sources observations. In the study area, heavy dusty condition is coupled with strong north wind which carried airmass contained high concentration of mineral dust particles with cold temperature and strong wind shear. This leads to weaker CAPE in dusty days comparing with that in pristine days. Based on satellite observations, the precipitating drops under dusty condition grow faster at middle layer (with temperature -5 °C to +2 °C) but slower at upper and lower layer comparing with the pristine counterpart. For a given precipitation top height, the precipitation rate under dusty condition is weaker in upper layer but heavier at middle and lower layer. And the associated latent heating rate released by precipitation at middle layer is stronger. The precipitation top temperature (PTT) shows fairly good linear relationship with near surface rain rate (NSRR). The linear regression slope between PTT and NSRR are stable at dusty and pristine conditions. However, the PTT0 (precipitation top temperature related to rain onset) at the onset of rain are highly affected by both CAPE and aerosol condition. In pristine days, stronger CAPE facilitate the vertical development of precipitation and leads to a decrease of PTT0 at the rate of -0.65 °C per 100 J kg-1 CAPE for deep convective precipitation with variation of 15 %, and by -0.41 °C per 100 J kg-1 CAPE for stratiform precipitation with variation of 12 %. After removing the impacts of CAPE on PTT, dust aerosols lead an increase of PTT at the rate by +4.19 °C per unit AOD for deep convective precipitation and by +0.35 °C per unit AOD for stratiform precipitation. This study showed clear evidence that meteorology conditions are combined with aerosol condition together to affect the vertical development of precipitation clouds. And quantitative estimation of the sensitivity of PTT to CAPE and dust were provided.
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Hongxia Zhu et al.
Status: closed
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RC1: 'Comment on acp-2022-492', Anonymous Referee #1, 08 Oct 2022
The authors present an investigation on the response of precipitation vertical structures to dust aerosols in southeastern China, which are mainly transported from northwestern China. The results are very interesting and understandable, and the analysis methods are quite scientifically solid. I would recommend accepting this paper after some improvement.
Major comments:
- Abstract: This work mainly investigated the dust aerosol impact on precipitation vertical structures using multi-source data, and gave statistical results. Nevertheless, I did not see the specific study area and time period.
- The titile of Section 2 of “Study area and data” needs to be rephrased, since most of the paragraphs focus on the methodology. As such, this section can be restructured. For instance, I do not understand what is the logic and purpose of the references such as “Teller and Levin (2006)” and Yin and Chen (2007), both of which are simply listed as seprated arguments and not tightly linked to the data or methodologies used in this study. In my opinion, these descriptions are more like related to the research status and can be moved to the introdution part.
- The English writing of this manuscript needs thorough improvement, and a complete polishing from the abstract to conclusion part is necessary with the help of native English speaker or a more experienced researchers.
- L204-206: In the presence of dust episode occurring in eastern China, a combination of high wind shear, low cape was observed, the author argued that “Such condition doesn’t favor the vertical development of convection.” Are there any literatures supporting this argument? In my view of point, the precipitation accompanied with dust episode is largely under the influence of large-scale circulation. This synoptic forcing favors the lifting of air mass and convection initiation. Besides, not every precipitation event was characterized by high CAPE, low wind shear.
Minor comments:
- “eastern China” in the title of this manuscript can be revised to “southeastern China”
- L14: “the study area” is suggested to be replaced with a specified area (e.g., southeast China?)
- L15: “contained”-> “containing”
- L34: “, they can” -> “, which can”
- L35: “to directly affect” -> “thereby directly affecting”
- L38: “warmer temperature” is not appropriate and can be revised to “higher temperature”
- L39: “server” -> “serve”
- L40: “moderate” can be revised to “mediate” or “modulate”
- L46: “Studies” -> “Previous studies”
- L78:“significantly was” -> “was significantly”
- L79: “. Such as” -> “, including”
- L83: I would suggest adding more recent references on the dependence of aerosol effect on precipitation on “the altitudes of the aerosol layer”, and the authors can refer to Lee et al. ACPD 2022 (https://doi.org/10.5194/acp-2022-385) and the referneces therein.
- L104: “In some studies,” in which studies? The authors can add references here to support this statement.
- L132: grammar errors in “, they are treated”.
- L137: The acronym for “precipitation top temperature” has been given in introduction part and in this place and the folllowing section, it is supposed to appear as “PTT”.
- L173: the references to ERA-5 reanalysis are lacking.
- L178: “during recent two decades” -> “during recent decades”
- L179-180: it is a too long sentence in “by anthropogenic emission related fine mode aerosols with small fraction of coarse mode aerosol”, and full of redudant words. I would suggest rewriting
- L181: “in which” or “when” can be added before “heavy dust aerosol”
- L182: “are” -> “were”, and “that” is missing before “were defined”
- L183: “excessed” -> “exceeded”
- L188-190: I would suggest clarifying whether the selected date of 12 June 2006 was also a rainy day in the southeast China.
- L199: “CAPE” is not an atmospheric dynamic variable
- L200: please clarify what is “strong coupling” between dusty condition and meteorology condition? It seems to me this term is contradictory with the following weak correlation observed between dust AOD and meteorology.
- L225: “start”-> “starting”
- L288 and L321: the full name for precipitation top height was actually given in L66, and thus should be avoided here.
- L362: Except for the “atmospheric thermodynamical effects”, the atmospheric dynamic impact can not be ignored.
- Figure 3: I would suggest adding the time period for which the meteorological fields are derived. Also the data sources are suggested to be added in this figure caption.
- Figure 11: it would be beneficial to give more descriptions in the figure caption on “70%” at the top of each panel in this figure. What does it mean, or how is it defined.
- AC1: 'Reply on RC1', Rui Li, 01 Dec 2022
-
RC2: 'Comment on acp-2022-492', Anonymous Referee #2, 17 Oct 2022
This study investigates the possible impacts of dust aerosol and convective available potential energy on precipitation vertical structure by using multiple source observations. Great efforts have been made to try to disentangle the aerosol and meteorological conditions. This manuscript is well designed, and the analysis methods are technically sound. However, the scientific and presentation quality need significant improvement. For example, 1) introduction section is a bit confusing for me. A lot of studies and findings were simply listed in a detailed but unclear way. In the end, it is still not clear what are the challenges in this topic and especially why this study is novel, which hampers the manuscript. I recommend the authors to revise this section into a good story; 2) section 3.2 is important and actually contains quite a lot interesting findings. But only the simple descriptions were presented without giving any discussion, implication or even comparison with previous studies. After reading this section, I don’t really get scientifically useful information. It’s more like a technical report. As such, I would recommend its publication pending the above-mentioned concerns and following specific comments satisfactorily addressed.
Specific comments
Line 16: How did author define the ‘pristine days’? It is incorrectly used if the authors only meant days with low dust concentrations, because other aerosol can dominate especially over east China.
In lines 49-57, the author showed the findings of dust aerosol weakening convection precipitation but immediately in lines 59-65 the opposite was listed. I would expect at least an explanation / mention here.
Lines 133-136: this is a repetition of lines 130-132.
MODIS-retrieved aerosol size parameters have little quantitative skill over land (e.g., https://doi.org/10.5194/amt-4- 201-2011). Thus, derivation of CMAOD from FMF is not a good try. In addition, how did the author consider the aerosol humidification effect in the presence of precipitation?
Lines 167-169: But it’s not always the case and even rarely happens that one precipitating grid can be surrounded by eight clear-sky grids.
Lines 169-171: Did the author take the study region as a whole when defining “dusty day”? For example, for a individual day, mean clear-sky CMAOD surrounding precipitating grids is larger than 0.5, in this case, how did the authors deal with other clear-sky CMAOD far away from precipitation? Also classify it as dusty days? This is not clear.
Line 173: It’s better to clarify how the authors did the spatial and temporal co-locations between TRMM and ERA5?
Lines 227-229: It is true for convective clouds but not for stratiform clouds. Can the authors explain the reason?
Line 231: Please develop a bit how dust can suppress warm rain?
Lines 236-239: As I understand, the contoured frequency by altitude diagrams is 2D probability density distribution, which represents how the data concentrate. Thus, it can not be used to illustrate if dust increases or decreases LH for a specific altitude. To do so, one should normalize data so that probability sums to 1 for each altitude, so called ‘joint-histgram’ .
Figure 6: Three LH methods are quite different with each other. I was wondering if the LH profiles are reliable? Why did author chosoe VPH in Figure 5? I don’t see any validation studies were cited. It is expected that the results will change quite a lot and also the conclusion will not hold anymore if other two methods are used since the vertical profiles have large difference as shown in Fig. 6.
Line 254: Why the warm rain was sometimes included and but sometimes not? Any reason?
Figure 9: It’s interesting that the dependence of Slope on PTT is getting stronger from C to A. Could the authors develop a bit on this? Also, Fig.9 was kind of repeating Fig.7 & 8. Although the plot types are different, all information as discussed in Fig 9 can be also seen in Fig 7&8. I recommend the author to condense a bit or put one into SI.
Line 313-315: What is the regression slope mentioned here? Can the authors explain more? How can the similar slopes indicate the growth rates of rain drops are similar under ‘pristine environment’?
Line 331: Good idea!
Lines 322-323: Any references support such argument?
- AC2: 'Reply on RC2', Rui Li, 01 Dec 2022
Status: closed
-
RC1: 'Comment on acp-2022-492', Anonymous Referee #1, 08 Oct 2022
The authors present an investigation on the response of precipitation vertical structures to dust aerosols in southeastern China, which are mainly transported from northwestern China. The results are very interesting and understandable, and the analysis methods are quite scientifically solid. I would recommend accepting this paper after some improvement.
Major comments:
- Abstract: This work mainly investigated the dust aerosol impact on precipitation vertical structures using multi-source data, and gave statistical results. Nevertheless, I did not see the specific study area and time period.
- The titile of Section 2 of “Study area and data” needs to be rephrased, since most of the paragraphs focus on the methodology. As such, this section can be restructured. For instance, I do not understand what is the logic and purpose of the references such as “Teller and Levin (2006)” and Yin and Chen (2007), both of which are simply listed as seprated arguments and not tightly linked to the data or methodologies used in this study. In my opinion, these descriptions are more like related to the research status and can be moved to the introdution part.
- The English writing of this manuscript needs thorough improvement, and a complete polishing from the abstract to conclusion part is necessary with the help of native English speaker or a more experienced researchers.
- L204-206: In the presence of dust episode occurring in eastern China, a combination of high wind shear, low cape was observed, the author argued that “Such condition doesn’t favor the vertical development of convection.” Are there any literatures supporting this argument? In my view of point, the precipitation accompanied with dust episode is largely under the influence of large-scale circulation. This synoptic forcing favors the lifting of air mass and convection initiation. Besides, not every precipitation event was characterized by high CAPE, low wind shear.
Minor comments:
- “eastern China” in the title of this manuscript can be revised to “southeastern China”
- L14: “the study area” is suggested to be replaced with a specified area (e.g., southeast China?)
- L15: “contained”-> “containing”
- L34: “, they can” -> “, which can”
- L35: “to directly affect” -> “thereby directly affecting”
- L38: “warmer temperature” is not appropriate and can be revised to “higher temperature”
- L39: “server” -> “serve”
- L40: “moderate” can be revised to “mediate” or “modulate”
- L46: “Studies” -> “Previous studies”
- L78:“significantly was” -> “was significantly”
- L79: “. Such as” -> “, including”
- L83: I would suggest adding more recent references on the dependence of aerosol effect on precipitation on “the altitudes of the aerosol layer”, and the authors can refer to Lee et al. ACPD 2022 (https://doi.org/10.5194/acp-2022-385) and the referneces therein.
- L104: “In some studies,” in which studies? The authors can add references here to support this statement.
- L132: grammar errors in “, they are treated”.
- L137: The acronym for “precipitation top temperature” has been given in introduction part and in this place and the folllowing section, it is supposed to appear as “PTT”.
- L173: the references to ERA-5 reanalysis are lacking.
- L178: “during recent two decades” -> “during recent decades”
- L179-180: it is a too long sentence in “by anthropogenic emission related fine mode aerosols with small fraction of coarse mode aerosol”, and full of redudant words. I would suggest rewriting
- L181: “in which” or “when” can be added before “heavy dust aerosol”
- L182: “are” -> “were”, and “that” is missing before “were defined”
- L183: “excessed” -> “exceeded”
- L188-190: I would suggest clarifying whether the selected date of 12 June 2006 was also a rainy day in the southeast China.
- L199: “CAPE” is not an atmospheric dynamic variable
- L200: please clarify what is “strong coupling” between dusty condition and meteorology condition? It seems to me this term is contradictory with the following weak correlation observed between dust AOD and meteorology.
- L225: “start”-> “starting”
- L288 and L321: the full name for precipitation top height was actually given in L66, and thus should be avoided here.
- L362: Except for the “atmospheric thermodynamical effects”, the atmospheric dynamic impact can not be ignored.
- Figure 3: I would suggest adding the time period for which the meteorological fields are derived. Also the data sources are suggested to be added in this figure caption.
- Figure 11: it would be beneficial to give more descriptions in the figure caption on “70%” at the top of each panel in this figure. What does it mean, or how is it defined.
- AC1: 'Reply on RC1', Rui Li, 01 Dec 2022
-
RC2: 'Comment on acp-2022-492', Anonymous Referee #2, 17 Oct 2022
This study investigates the possible impacts of dust aerosol and convective available potential energy on precipitation vertical structure by using multiple source observations. Great efforts have been made to try to disentangle the aerosol and meteorological conditions. This manuscript is well designed, and the analysis methods are technically sound. However, the scientific and presentation quality need significant improvement. For example, 1) introduction section is a bit confusing for me. A lot of studies and findings were simply listed in a detailed but unclear way. In the end, it is still not clear what are the challenges in this topic and especially why this study is novel, which hampers the manuscript. I recommend the authors to revise this section into a good story; 2) section 3.2 is important and actually contains quite a lot interesting findings. But only the simple descriptions were presented without giving any discussion, implication or even comparison with previous studies. After reading this section, I don’t really get scientifically useful information. It’s more like a technical report. As such, I would recommend its publication pending the above-mentioned concerns and following specific comments satisfactorily addressed.
Specific comments
Line 16: How did author define the ‘pristine days’? It is incorrectly used if the authors only meant days with low dust concentrations, because other aerosol can dominate especially over east China.
In lines 49-57, the author showed the findings of dust aerosol weakening convection precipitation but immediately in lines 59-65 the opposite was listed. I would expect at least an explanation / mention here.
Lines 133-136: this is a repetition of lines 130-132.
MODIS-retrieved aerosol size parameters have little quantitative skill over land (e.g., https://doi.org/10.5194/amt-4- 201-2011). Thus, derivation of CMAOD from FMF is not a good try. In addition, how did the author consider the aerosol humidification effect in the presence of precipitation?
Lines 167-169: But it’s not always the case and even rarely happens that one precipitating grid can be surrounded by eight clear-sky grids.
Lines 169-171: Did the author take the study region as a whole when defining “dusty day”? For example, for a individual day, mean clear-sky CMAOD surrounding precipitating grids is larger than 0.5, in this case, how did the authors deal with other clear-sky CMAOD far away from precipitation? Also classify it as dusty days? This is not clear.
Line 173: It’s better to clarify how the authors did the spatial and temporal co-locations between TRMM and ERA5?
Lines 227-229: It is true for convective clouds but not for stratiform clouds. Can the authors explain the reason?
Line 231: Please develop a bit how dust can suppress warm rain?
Lines 236-239: As I understand, the contoured frequency by altitude diagrams is 2D probability density distribution, which represents how the data concentrate. Thus, it can not be used to illustrate if dust increases or decreases LH for a specific altitude. To do so, one should normalize data so that probability sums to 1 for each altitude, so called ‘joint-histgram’ .
Figure 6: Three LH methods are quite different with each other. I was wondering if the LH profiles are reliable? Why did author chosoe VPH in Figure 5? I don’t see any validation studies were cited. It is expected that the results will change quite a lot and also the conclusion will not hold anymore if other two methods are used since the vertical profiles have large difference as shown in Fig. 6.
Line 254: Why the warm rain was sometimes included and but sometimes not? Any reason?
Figure 9: It’s interesting that the dependence of Slope on PTT is getting stronger from C to A. Could the authors develop a bit on this? Also, Fig.9 was kind of repeating Fig.7 & 8. Although the plot types are different, all information as discussed in Fig 9 can be also seen in Fig 7&8. I recommend the author to condense a bit or put one into SI.
Line 313-315: What is the regression slope mentioned here? Can the authors explain more? How can the similar slopes indicate the growth rates of rain drops are similar under ‘pristine environment’?
Line 331: Good idea!
Lines 322-323: Any references support such argument?
- AC2: 'Reply on RC2', Rui Li, 01 Dec 2022
Hongxia Zhu et al.
Hongxia Zhu et al.
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