aaqr.org/articles/aaqr-19-03-achr-0146
Emission Hotspots & Trends: The study identifies significant increases in open biomass burning (OBB) emissions in Punjab (83–106%) and Myanmar (2338–3054%) compared to anthropogenic sources, using long-term data from GFED4s and FINN.
Carbonaceous Aerosol Impact: OBB emits large quantities of carbonaceous aerosols (black carbon and organic carbon), which rise up to 3–5 km and disperse across South Asia, affecting regional air quality.
Radiative Forcing Effects: The aerosols result in substantial negative radiative forcing—up to –6.14 W/m² at the surface and –0.50 W/m² at the top of the atmosphere in Punjab, with even stronger effects over Myanmar.
Weather Modifications: Carbonaceous aerosols reduce surface temperature by ~2 K, increase relative humidity by ~8%, and alter the planetary boundary layer height by up to 600 m, impacting regional meteorology. Increased atmospheric stability creates positive feedback for air pollution in IGP.
https://www.mdpi.com/2073-4433/12/9/1092
Model Performance & Resolution: WRF-Chem effectively simulates observed precipitation patterns; however, minimal differences between 25 km and 4 km resolutions suggest that parameterization sensitivity at finer scales needs further refinement.
Rainfall Influence of Aerosols: Presence of aerosols leads to a 20–50% change in rainfall over Kedarnath, showing that aerosol–cloud interactions significantly impact precipitation intensity during deep convective events.
Aerosol Transport & Impact: Simulations reveal strong vertical transport of aerosols—natural aerosols increase by 50%+, and anthropogenic aerosols by 200%+—altering cloud microphysics including rain and ice concentrations.
Instability Modulation: Aerosol–radiation feedback causes notable changes in atmospheric instability metrics (e.g., CAPE, CIN, and vorticity), highlighting aerosols’ potential role in intensifying severe weather in the Himalayas.
https://www.sciencedirect.com/science/article/pii/S0169809519309500
Persistent Upper-Level BC Plume: Model simulations and analysis reveal a stable and persistent BC layer above 500 hPa over central India during the monsoon season, linked to anti-cyclonic circulation in the upper troposphere.
Limited Vertical Transport on Convective Days: Despite favorable conditions like high CAPE and helicity, simulations do not show significant BC reaching the upper troposphere-lower stratosphere (UT/LS) during individual high-convection days.
Higher Free Tropospheric BC in Monsoon: Seasonal analysis indicates elevated BC concentrations in the free troposphere during the monsoon compared to winter, highlighting the role of monsoonal dynamics in vertical redistribution.
Model Gaps in Himalayan Region: While the model captures BC trends for most of South Asia, it underperforms over central Himalayan cities—pointing to a need for improved parameterizations for advection and boundary conditions.
https://link.springer.com/article/10.1007/s00382-024-07291-2
Ensemble Design: An international team conducted 13 high-resolution (2.2–4 km) regional climate simulations covering October 2019 to September 2020, forming the first kilometer-scale ensemble for the entire Third Pole.
Methodology: The simulations, part of a CORDEX Flagship Pilot Study, use ERA5 reanalysis as boundary conditions and apply various models and physical configurations to capture regional complexities.
Performance Evaluation: Despite discrepancies among reference precipitation datasets, the ensemble generally outperforms ERA5 in capturing warm-season precipitation patterns, wet-day frequency, hourly rainfall, and wet spell characteristics.
Future Value: The ensemble offers a valuable foundation for improving hydroclimate process understanding and supports future climate impact assessments in this climatically sensitive and topographically complex region.
https://doi.org/10.3390/atmos16030327
Elevation-Dependent Warming: All datasets show a positive elevation-dependent warming trend in winter and autumn, with the intensity of warming varying across the datasets.
Elevation-Dependent Wetting: Positive elevation-dependent wetting trends are observed in all seasons except autumn, mainly due to drying at lower elevations and relatively stable precipitation at higher elevations.
Dataset-Specific Characteristics: ERA5 and IMDAA yield similar results; TPRR shows more extreme and distinct temperature trends; HAR-v2 displays milder variations in both temperature and precipitation trends.
Importance of Validation: The study stresses the need to validate reanalysis datasets against in situ and satellite observations to determine the most reliable dataset for EDCC studies, especially in data-sparse regions.
https://doi.org/10.5194/acp-25-17869-2025
Lightning Moisture Link: Lightning-intense deep convective systems over the Himalayas are closely associated with enhanced water vapour transport into the upper troposphere.
Model Observation Consistency: Both ICON-CLM simulations and satellite datasets (AIRS, MLS) show increased upper-tropospheric moisture during lightning events, though ERA5 tends to overestimate this effect, particularly during the monsoon.
Transport Dynamics: ERA5 indicates slow, widespread horizontal transport of moist air over the Tibetan Plateau, while the km-scale ICON-CLM simulates faster, more localized vertical transport.
UTLS Moistening Extent: Lightning-driven convection generally moistens the upper troposphere, but only a few events contribute directly to lower stratospheric moistening, with outcomes influenced by synoptic-scale circulation.
