In the avenue of my research 🗒️ ….. I do air pollution studies by leveraging model simulation, satellite, reanalysis, and observation datasets. Over time, I have used different models and satellite products and worked on a wide spectrum of fields, including spatial-temporal distribution and contribution of aerosol species, vertical distribution, the synergy of aerosol-PBL mechanisms, long-range transport, and radiative perturbation. Now I have focused more on long-range transport and extending the concept of the atmospheric river in terms of aerosols/trace gases. I am using transport diagnostic tools that leverage the atmospheric river concept, tropospheric chemistry reanalysis products, and new satellite observations of Carbon Monoxide (CO), Ozone (O3) and Peroxyacetyl Nitrate (PAN) produced by NASA JPL to analyze large-scale transport of trace gases, improve the use of satellite observations in transport analysis, evaluate current chemistry reanalysis and satellite products, characterize long-range transport phenomena, and quantify impacts on local air quality extremes. In a sense, I will be using the data from the multi-model, multi-constituent chemical data assimilation (MOMO-Chem) framework to extending the concept of the atmospheric river in terms of trace gases.
Tracing Atmospheric Anthropogenic Black Carbon and Its Potential Radiative Response Over Pan-Third Pole Region: A Synoptic-Scale Analysis Using WRF-Chem
The Pan-Third Pole contains the largest number of glaciers outside the polar region that plays a crucial role in atmospheric circulation and the hydrological cycle. However, this pristine region has undergone rapid change through complex interactions including the black carbon (BC) enhanced warming effect and glacier melting. Study shows, Weather Research and Forecasting coupled with Chemistry (WRF-Chem) simulation is able to capture distinctive seasonal variability of BC. The result from our sensitivity experiments revealed that South Asia (SA; 60.7%) and East Asia (EA; 32.9%) contributed more toward the Tibetan Plateau (TP). Our analysis on aerosol-boundary feedback interaction revealed BC expand planetary boundary layer height by 5.0% and 4.8% over SA and EA, respectively, which facilitates BC dispersion and transportation. Whereas, we also found that under the influence of different wind regimes the significant BC transport flux aloft over the TP and the upper troposphere and lower stratosphere. Additionally, mountain-valley channel and synoptic and local meteorological processes also facilitated BC transport to the TP. This study also evaluated the effect of BC on direct radiative forcing and calculated subsequent temperature changes. A strong dimming effect of BC corroborated with the following negative surface temperature changes. However, enhanced BC concentration during winter and spring caused the increase in temperature over the TP. Here, the WRF-Chem model, synergy on aerosol-boundary feedback, BC transport flux, and source-receptor methods confirmed the significant BC contribution and transportation, and notable BC-induced warming over TP. Such transHimalayan BC transport and associated warming could grim glacier melt and water availability in the region.
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South Asian black carbon is threatening the water sustainability of the Asian Water Tower Long-range transport of black carbon from South Asia to the Tibetan plateau and its deposition on glaciers directly enhances glacier melt. Here we find South Asian black carbon also has an indirect effect on the plateau’s glaciers shrinkage by acting to reduce the water supply over the southern Tibetan plateau. Black carbon enhances vertical convection and cloud condensation, which results in water vapor depletion over the Indian subcontinent that is the main moisture flux source for the southern Tibetan plateau. Increasing concentrations of black carbon causes a decrease in summer precipitation over the southern Tibetan plateau, resulting in 11.0% glacier deficit mass balance on average from 2007 to 2016; this loss rises to 22.1% in the Himalayas. The direct (accelerated melt) and indirect (mass supply decrease) effects of black carbon are driving the glacial mass decline of the so-called “Asian Water Tower”.
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