the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Aerosol-meteorology feedback diminishes the trans-boundary transport of black carbon into the Tibetan Plateau
Yuling Hu
Shichang Kang
Haipeng Yu
Junhua Yang
Mukesh Rai
Xiufeng Yin
Xintong Chen
Pengfei Chen
Abstract. Black carbon (BC) exerts potential effect on climate, especially in the Tibetan Plateau (TP), where the cryosphere and environment are very sensitive to climate change. The TP saw the record-breaking aerosol pollution event during the period from April 20 to May 10, 2016. This paper investigated the meteorological causes, trans-boundary transport flux of BC, and aerosol-meteorology feedback as well as its effect on trans-boundary transport flux of BC during this severe aerosol pollution event via using observational and reanalysis dataset and simulation from the coupled meteorology and aerosol/chemistry model (WRF-Chem). By analyzing the weather maps derived from reanalysis dataset, it is found that the plateau vortex and southerly winds were key factors that contributed to the severe aerosol pollution event. Subsequently, with the good performance of WRF-Chem model on the spatiotemporal characteristics of meteorological conditions and aerosols, the trans-boundary transport flux of BC during the pollution event was investigated. The results show that the vertically integrated cross-Himalayan transport flux of BC decreases from west to east, with the largest transport flux of 20.8 mg m−2 s−1 occurring at the deepest mountain valley in southwestern TP. Results from simulations with and without aerosol-meteorology feedback show that aerosols induce significant changes in meteorological conditions in the southern TP and Indo-Gangetic Plain (IGP), with the atmospheric stratification being more stable and the planetary boundary layer height decreasing in both regions, and 10-m wind speed increasing in the southern TP but decreasing in the IGP. Changes in meteorological conditions in turn lead to a decrease of surface BC concentration with value up to 0.16 μg/m3 (50 %) in the southern TP and an increase of surface BC concentration with value up to 2.2 μg/m3 (75 %) in the IGP. By excavating the impact of aerosol-meteorology feedback on the trans-boundary transport flux of BC, it has been acquired that the aerosol-meteorology feedback decreases the integrated transport flux of BC from central and western Himalayas towards the TP. This study not only provides crucial policy implications for mitigating glacier melt caused by aerosols over the TP, but also is of great significance to the ecological environment protection for the TP.
- Preprint
(8147 KB) -
Supplement
(1838 KB) - BibTeX
- EndNote
Yuling Hu et al.
Status: open (until 05 Jun 2023)
-
RC1: 'Comment on egusphere-2023-252', Anonymous Referee #1, 14 May 2023
reply
General comments
The manscript reported a record-breaking aerosol pollution event in the TP. Cross-boundary transport along the south slope the Himalayas from the surrounding regions was clearly the cause, implying galcier melt and ecological environment disturbtion for the TP. Due to the extremely scarce avaiblity of field observations, however, cross-boundary transport flux, meterological pattern delivering aerosol, and the aerosol-meteorology feedback have rarely been discussed. The manuscript clearly shows strong aerosol-meteorology feedback on the transpor flux of aerosols. The strong feedback on meteorology and aerosol distribution are also discussed in details. I hence recommanded this manuscript for publication in ACP.
Specific comments
- The measurement distinguish this manuscript and also a previous one, i.e., zhang et al., 2020, written by the key authors from a pure model simulation. However, these major results on transport flux and the aerosol-meteorology feedback are merely model simulations? Whether do the observation here or in other places reflect the pattern of transport flux or the aerosol-meteorology feedback pattern on transport flux?
- Although observation-model comparison on BC concentration and AOD have been conducted, these results do not fully justify the simulated transport flux pattern? More regious comparisons also transport flux among observations/reanalysis and models, or intermodel comparison on transport flux, might be helpful?
- The WRF-Chem experiments take advantage of the record-breaking aerosol pollution event and run with aerosol-meteorology feedback on or off. Is there any observational evidence that aerosol-meteorology feedback changes the distribution or transport flux of BC? Is there model evidences that aerosol-meteorology feedback model better capture the observation of BC concentration or transport flux?
- Zhang et al., 2020 suggest that model resolving more valleys and mountains better capture valley transport and overall cross-Himalayan transport. As the authors have discussed potential weakness in current 15 km resolution model, will the current model be statisfying in simulatiing the aerosol-meteorology feedback?
- From Figure 7 & Figure 13, the aerosol-meteorology feedback does not simply lower the transport flux as written in the title?
- The authors know cleary the uncertainties in a pure model simulation (in lines 906-917). A disscussion on wanted future experiments to constrain these ucnertainties would be nice.
Citation: https://doi.org/10.5194/egusphere-2023-252-RC1 -
RC2: 'Comment on egusphere-2023-252', Anonymous Referee #2, 17 May 2023
reply
The interaction between aerosols and meteorology, and its impact on the cross-boundary transport flux of BC (black carbon) over the Tibetan Plateau (TP), has received limited attention in previous research. This paper presents a comprehensive investigation of the aerosol-meteorology feedback and its influence on BC transport flux during a period of heavy aerosol pollution. The study utilizes WRF-Chem simulation to thoroughly analyze the phenomenon. Additionally, the paper elucidates the meteorological factors that contribute to the occurrence of severe aerosol pollution events over the TP. The concept introduced in this article is characterized by its novelty, and the study's findings hold significant implications for the preservation of the TP's ecological environment. Hence, I recommend that this manuscript be revised and considered for publication in ACP. Please find below some specific comments for further improvement:
- The authors validated the model performance on BC and AOD by comparing the simulation and observation. Although the comparison results are basically satisfactory, the data used to validate the model performance is still simple and I suggest inter-model comparison should be considered, which might be more convincing.
- When analyzing the meteorological causes of the heavy aerosol pollution event, isotherms in the weather maps in Figure 3 are not included in the analysis, and isotherms lead to blurring of potential heights and wind fields in weather maps, so I suggest removing them.
- As the author stated in the title as well as in Figure.12, the aerosol-meteorology feedback decreased the cross-boundary transport flux of BC towards the TP. In fact, this conclusion is the result of pure model simulation because of the harsh environment, limited access for fieldwork, and the sparsity of fixed instrumental stations over the TP. So is there similar study in other places and What effect does the aerosol-meteorology feedback have on the transport flux of aerosols?
- Line 949, Line 1090, Line 1176, Line 1213–1214, and Line 1227: ATMOSPHERIC CHEMISTRY AND PHYSICS --> Atmos. Chem. Phys.
- Line 1128: JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES --> Journal of Geophysical Research: Atmospheres
- Line 1034–1035: NATURE CLIMATE CHANGE -->Nature Climate Change
- Line 1220: SCIENTIFIC REPORT--> Scientific Report
- Line 1221–1224: The corresponding article is quoted incorrectly and lacks the journal name.
Citation: https://doi.org/10.5194/egusphere-2023-252-RC2
Yuling Hu et al.
Yuling Hu et al.
Viewed
| HTML | XML | Total | Supplement | BibTeX | EndNote | |
|---|---|---|---|---|---|---|
| 235 | 60 | 7 | 302 | 22 | 2 | 2 |
- HTML: 235
- PDF: 60
- XML: 7
- Total: 302
- Supplement: 22
- BibTeX: 2
- EndNote: 2
Viewed (geographical distribution)
| Country | # | Views | % |
|---|
| Total: | 0 |
| HTML: | 0 |
| PDF: | 0 |
| XML: | 0 |
- 1