Upward Air Motion Research Articles

Connection between Barents Sea Ice in May and Early Summer Monsoon Rainfall in the South China Sea and Its Possible Mechanism

The impacts of Arctic sea ice on climate in middle and high latitudes have been extensively studied. However, its effects on climate in low latitudes, particularly on summer monsoon rainfall in the South China Sea (SCS), have received limited attention. Thus, this study investigates the connection between the Arctic sea ice concentration (SIC) anomaly and the early summer monsoon rainfall (ESMR) in the SCS and its underlying physical mechanism. The results reveal a significant positive correlation between the Barents Sea (BS) SIC in May and the ESMR in the SCS. When there is more (less) SIC in the Barents Sea (BS) during May, this results in a positive (negative) anomaly of the local turbulent heat flux, which lasts until June. This, in turn, excites an upward (downward) air motion anomaly in the vicinity of the BS, causing a corresponding downward (upward) motion anomaly over the Black Sea. Consequently, this triggers a wave train similar to the Eurasian (SEU) teleconnection, propagating eastward towards East Asia. The SEU further leads to an (a) upward (downward) motion anomaly and weakens (strengthens) the western Pacific subtropical high (WPSH) over the SCS, which is accompanied by a southwest adequate (scarce) water vapor anomaly transporting from the Indian Ocean, resulting in more (less) precipitation in the SCS. Furthermore, the response of ESMR in the SCS to the SIC in the BS is further verified by using the Community Atmosphere Model version 5.3 (CAM5.3). This study introduces novel precursor factors that influence the South China Sea summer monsoon (SCSSM), presenting a new insight for climate prediction in this region, which holds significant implications.

Influence of the Madden-Julian Oscillation on the diurnal cycles of convection and precipitation over the Congo Basin

The Congolese rainforest is a hotspot for convection where thunderstorms and rainfall exhibit a strong diurnal cycle. Previous studies have shown that various modes of variability such as the Madden-Julian Oscillation (MJO), the leading mode of intraseasonal variability in the tropics, can impact the diurnal cycles of precipitation and convection over tropical land areas. Thus, this study analyzes the influence of the MJO on diurnal variations of convection and precipitation over the Congo and explores possible mechanisms leading to the observed changes, using Gridded Satellite (GridSat-B1), Tropical Rainfall Measuring Mission (TRMM), and ERA5 reanalysis data. Results show that convection and precipitation are increased during the MJO enhanced convective phase (RMM phases 1 and 2) and decreased during the suppressed convective phase (RMM phases 5 and 6), where the differences are found to be largest during the morning hours when convection is weakest. Convection is generally deeper during the enhanced phase and shallower during the suppressed phase, accompanied by a slower decay of convective clouds and anvils during the enhanced phase. Furthermore, the influence of the MJO was found to be stronger on stratiform precipitation compared to convective precipitation. While the diurnal cycles of convective precipitation fractions are similar during both MJO phases, the fraction of stratiform precipitation is higher during the enhanced phase, mainly in the morning hours. Suggested atmospheric drivers contributing to the observed differences between the two MJO phases include enhanced upward air motion in the mid- and upper levels and strong divergence in the upper levels during the enhanced phase, and strong mid-level divergence and upper- to mid-level subsidence during the suppressed phase, mainly during the nighttime and morning hours. Furthermore, decreased mid-level wind speed, increased upper-level wind speed, and enhanced relative humidity may be contributing factors to the increased formation of stratiform precipitation during the enhanced phase. These results enhance our understanding of the MJO's impacts on precipitation and convection variability, ultimately improving predictions of MJO modulated rainfall over the Congo.

The Performance of S2S Models on Predicting the 21.7 Extreme Rainfall Event in Henan China

Extreme rainfall may cause meteorological disasters and has tremendous impact on societies and economics. Assessing the capability of current dynamic models for rainfall prediction, especially extreme rainfall event prediction, at sub-seasonal to seasonal (S2S) scale and diagnosing the probable reasons are quite important topics in the current climate study field. This study analyzes the formation mechanisms of the extreme rainfall event during 18–22 July 2021 in Henan Province and introduces the Tanimoto Coefficient (TC) to evaluate the prediction performance of S2S models. The results show that confrontation between low-latitude typhoon “In-Fa” and subtropical highs leads to sufficient water vapor transporting to Henan, and that remarkable upward air motion causes strong convergence of water vapor, thereby providing atmospheric conditions for this extreme rainfall event. Furthermore, five S2S models showed limited capability in predicting this extreme rainfall event 20 days in advance with the TCs of four models being below 0.1. Models could capture this event signal 6 days ahead with most TCs above 0.2. The performances of model prediction for this extreme rainfall event were closely related to the fact that the water vapor convergence, vertical movements, relative vorticity, and geopotential height predicted by the NCEP model 20 days ahead were close to the actual situation, in contrast to the other four models 6 days in advance. This study implies that S2S model predictions for this extreme rainfall event show obvious differences, and the application of S2S models in the prediction of extreme events needs to fully consider their prediction uncertainties. The capability of the models to properly reproduce local water vapor convergence and vertical motions is also shown to be crucial for correctly simulating the extreme event, which might provide some hints for the further amelioration of models.

Solving optimal reactive power problem by hurricane search optimization algorithm

In this paper Proposed Hurricane Search Optimization (HSO) algorithm is proposed to solve optimal reactive power problem. An upward motion of air is caused due to release of heat which creates a low-pressure zone and by the rotation of the earth that is set into spin. In this spiraling airflow when energy is high then hurricane is created. Projected Hurricane Search Optimization (HSO) algorithm<strong> </strong>design is based on the examination of the horizontal wind structure in a hurricane and how the wind parcels the progression in the neighboring atmosphere. A mixture of wind models has been developed for past few years to Backtesting and to compute hurricane exterior wind fields. Proposed Hurricane Search Optimization (HSO) algorithm has been tested in standard IEEE 30, 57bus test systems and simulation results show the projected algorithm reduced the real power loss considerably.

Three-dimensional Thermal and Dynamic Structure in Synoptic and Local Scale and its Influence on Haze Formation during Autumn in Beijing

ABSTRACT This study investigates the vertical thermal and dynamic structure of the atmosphere on synoptic and local scales from a three-dimensional perspective and its contribution to haze formation in Beijing during autumn. On a synoptic scale, the occurrence of heavy haze corresponds either to significant horizontal pollutant transport by southerly winds or to strong atmospheric vertical stability with downward air motion at altitudes below ~1500–3000 m; hence, meteorological parameters measured below ~1500 m serve as better indicators of pollutant transport and dispersion than surface observations. When accompanied by increased southerly winds, the upward air motion between the ground and altitudes above ~1500 m can transport pollutants from surrounding areas to Beijing, resulting in a rapid increase in PM2.5 (within several hours) despite weak winds on the surface, which confirms the possibility of regional transport during stagnant surface conditions and its potential role in haze formation. Additionally, the mountain-plain breeze in the Beijing-Tianjin-Hebei (BTH) region during autumn drives strong local wind circulation, influencing the cumulative stage of haze episodes in this season. During the daytime, this breeze pushes pollutants to areas along the mountains and then to Beijing, resulting in a day-by-day increase in pollution. (By contrast, winter haze episodes arise from the accumulation of local pollution under stable meteorological conditions.) The combination of easterly winds and local topography can induce the formation and dissipation of haze, with the orographic effect propelling the haze into higher layers that host the transport of PM2.5 to the southeast. Afterward, southerly winds carry this pollution plume back along the mountain front, where it merges with surface pollutants through vertical mixing, finally this mixed plume arrived Beijing and contributes to the development of the next haze episode.

Thermal Convection Mechanics

Assuming thermal convection takes place continuously inside the North Pacific High, an application of physics to the rising sea-warmed air plumes increases understanding of the relatively high air pressure at the sea surface and at the bases of the plumes. Since the ocean is warmer than the air under the NPH, heat is transferred upward decreasing the air density, which should then accelerate upward when no other forces are around to stop it. By Newton’s 3rd law the upward accelerating air will cause an equal but opposite (downward) reaction resulting in high pressure in the air under the rising column. That is the central proposal offered, which is consistent with available observations. New data that confirm the upward acceleration of the heated air are especially needed. Perhaps dye or neutrally buoyant particles could be released from a ship or buoy to make the upward air motion visible.

Thermal Convection Mechanics

Assuming thermal convection takes place continuously inside the North Pacific High, an application of physics to the rising sea-warmed air plumes increases understanding of the relatively high air pressure at the sea surface and at the bases of the plumes. Since the ocean is warmer than the air under the NPH, heat is transferred upward decreasing the air density, which should then accelerate upward when no other forces are around to stop it. By Newton’s 3rd law the upward accelerating air will cause an equal but opposite (downward) reaction resulting in high pressure in the air under the rising column. That is the central proposal offered, which is consistent with available observations. New data that confirm the upward acceleration of the heated air are especially needed. Perhaps dye or neutrally buoyant particles could be released from a ship or buoy to make the upward air motion visible.

A Mathematical Model of Tornado

We propose a mathematical model of tornado in the framework of continuum mechanics. According to this model, the swirling upward air motion in a tornado can be explained even without taking into account the Coriolis force or the vertical convection of warm air. Our results show that for a tornado to appear two factors are necessary: a powerful rotational motion of air in the upper atmosphere and the growth of air pressure from the center to the periphery of an expected region of tornado. The characteristics of air flow in tornado can be found by solving a boundary value problem for a nonlinear parabolic integro-differential equation for an unknown complex-valued temperature. We formulate this problem, propose an algorithm for its numerical solution, and examine its stationary solutions by the stabilization method.

Effects of Shipping-originated Aerosols on Physical Cloud Properties over Marine Areas near East China

ABSTRACT Shipping emissions have received increasing attention due to their influence on regional climate, and air quality at ports and in coastal areas around the world. In the context of climatology, the effects of shipping-originated aerosols (using the aerosol optical depth, AODship, as a proxy) on clouds in marine areas near East China were examined based on multi-satellite datasets. On average, AODship is approximately 0.17, 0.20, 0.15 and 0.13 in the different seasons, contributing 23%, 30%, 36% and 25% of the total AOD, respectively. In remote sea areas, AODship is generally higher in spring and summer and lower in autumn. Statistical analysis shows that it is strongly related to the cloud parameters, such as the cloud fraction (CF), cloud optical thickness (COT) and cloud effective radius (CER) in the liquid phase. In particular, CER and AODship exhibit a positive correlation in winter but a weakly negative correlation in summer over the northern East China Sea and a positive correlation in spring and summer over the Yellow Sea. In all four seasons, COT and CF decrease as AODship increases. The correlations between AODship and the cloud properties are stronger (R > 0.3) when the aerosol-cloud layers are well mixed than when they are separated, indicating that shipping-originated aerosols drawn into the cloud body can directly affect the microphysical properties of cloud droplets during cloud formation. The water vapor content and upward air motion are key thermodynamic conditions within the low atmospheric layers under the cloud bottom that play an important role in cloud formation and development. Our results provide new insight into the influence of shipping emissions on clouds in Asian marine areas.

Classification and Diurnal Variations of Precipitation Echoes Observed by a C-band Vertically-Pointing Radar in Central Tibetan Plateau during TIPEX-III 2014-IOP

This study investigates classification and diurnal variations of the precipitation echoes over the central Tibetan Plateau based on the observations collected from a C-band vertically-pointing frequency-modulated continuous-wave (C-FMCW) radar during the Third Tibetan Plateau Atmospheric Scientific Experiment (TIPEX-III) 2014-Intensive Observation Period (2014-IOP). The results show that 51.32% of the vertical profiles have valid echoes with reflectivity > –10 dBZ, and 35.06% of the valid echo profiles produce precipitation at the ground (precipitation profiles); stratiform precipitation with an evident bright-band signature, weak convective precipitation, and strong convective precipitation account for 52.03%, 42.98%, and 4.99% of the precipitation profiles, respectively. About 59.84% of the precipitation occurs in the afternoon to midnight, while 40.16% of the precipitation with weaker intensity is observed in the nocturnal hours and in the morning. Diurnal variation of occurrence frequency of precipitation shows a major peak during 2100–2200 LST (local solar time) with 59.02% being the stratiform precipitation; the secondary peak appears during 1300–1400 LST with 59.71% being the weak convective precipitation; the strong convective precipitation occurs mostly (81.83%) in the afternoon and evening with two peaks over 1200–1300 and 1700–1800 LST, respectively. Starting from approximately 1100 LST, precipitation echoes develop with enhanced vertical air motion, elevated echo top, and increasing radar reflectivity. Intense upward air motion occurs most frequently in 1700–1800 LST with a secondary peak in 1100–1400 LST, while the tops of precipitation echoes and intense upward air motion reach their highest levels during 1600–1800 LST. The atmospheric conditions in the early morning are disadvantageous for convective initiation and development. Around noon, the convective available potential energy (CAPE) increases markedly, convective inhibition (CIN) is generally small, and a super-dry-adiabatic layer is present near the surface (0–400 m). In the early evening, some larger values of CAPE, level of neutral buoyancy, and total precipitable water are present, suggesting more favorable thermodynamic and water vapor conditions.

Performance evaluation of RegCM4 in simulating temperature and precipitation climatology over India

In this study, the performance of the Regional Climate Modeling system version 4 (RegCM4) is evaluated over Indian regions through a 30-year climate simulation. The main focus is given on the model bias, correlation between the model simulated and observed results, and the standard error in the model simulations towards the 30-year mean temperature and precipitation climatology and their inter-annual and inter-decadal variability over India and the subregions. We find that the model-simulated temperature climatology has ~ 2 °C cold bias and the precipitation climatology has ~ 0.8 mm/day dry bias over India. Major cold bias (~ 3 °C) is noticed over South Peninsular India in the temperature climatology and a significant dry bias (~ 3 mm/day) is seen over Northeast India in the precipitation climatology. The performance skill of the model is found best over Northwest India for both temperature and precipitation, while it is found poor over South Peninsular India for temperature, and Northeast India for precipitation. Our overall results indicate that the RegCM4 reproduced the temperature climatology reasonably well over Indian regions, while it underestimated the precipitation climatology over many regions particularly during monsoon season. We find that less availability of moisture in the atmosphere and perhaps a weaker convection due to weaker upward motion of air may lead to decrease the precipitation in the model.

Transport of Pollutants by the Sea Breeze in São Paulo under the South Atlantic High

The land-sea breeze circulation is important for the Metropolitan Region of São Paulo (MRSP), influencing predominant wind direction during the night and day, and so, the transport of pollution in the local scale. In the summer of 2014, there were 43 exceedances of the state air quality by ozone, when the South Atlantic Subtropical High strengthened over southeast Brazil. We aimed to study how the land-sea breeze circulation influenced the transport of the pollutants CO, NO, NO2 and O3 in the study area using the WRF/Chem model in the period 28/01-01/02/2014. Two scenarios were considered: CTRL – vehicular emissions based on current emission inventories and SENS – removing 75% of emissions in the MRSP. Results were analysed through maps with the spatial distribution of pollutants in the domain and showed the importance of the land-sea breeze circulation for the transport of pollution. Analysis of the divergence field proved useful for identifying the sea breeze front. Higher O3 concentrations were simulated in the prefrontal convergence line, due to stagnation and accumulation of pollutants brought by the passage of the sea breeze over polluted areas, resulting in the transport of ozone and other pollutants to distant areas northwest during the afternoon and evening. There was also transport of pollutants to the south in the early morning caused by the land breeze. Upward air motion due to the convergence in the prefrontal region caused vertical transport of ozone during the afternoon.

Life Cycle Effects on the Vertical Structure of Precipitation in East China Measured by Himawari-8 and GPM DPR

Abstract We identified precipitating systems from May to August 2016 using data from the Global Precipitation Measurement mission Dual-frequency Precipitation Radar instrument. Then, using this set of cases, Himawari-8 10.4-μm brightness temperature data from before and after each precipitation event were used to identify three life stages of clouds: a developing stage, a mature stage, and a dissipating stage. Using statistical analysis and two case studies, we show that the precipitating systems at different life stages of the clouds have different systematic properties, including the area of precipitation, the convective ratio, the rain-top height, and the brightness temperature. The developing systems had the largest convective ratio, whereas the dissipating systems had the largest area of precipitation. The life stage of the cloud also influenced the vertical structure of the precipitation. The microphysical processes within each stage were unique, leading to various properties of the droplets in precipitation. The developing systems had large, but sparse, droplets; the mature systems had large and dense droplets; and the dissipating systems had small and sparse droplets. Our results suggest that the different properties of precipitating systems in each life cycle stage of clouds are linked to the cloud water content and the upward motion of air.

Distinct responses of East Asian and Indian summer monsoons to astronomical insolation during Marine Isotope Stages 5c and 5e

Loess and stalagmite records in China show different responses of Asian monsoon to the astronomical insolation during Marine Isotope Stage (MIS) 5c and 5e, raising the question whether the amplitudes of the whole Asian monsoon are linearly controlled by the astronomical summer insolation changes and whether the regional differences exist. In this study, a set of numerical experiments are conducted for these stages to examine the sensitivity of Asian summer monsoon to changes in the astronomical parameters. The results highlight a complicated response changing with regions and signals. The East Asian monsoon is remarkably stronger during MIS-5e, which is characterized by southerly winds, primarily due to the anomalous anticyclone over northwestern Pacific. The intensified East Asian monsoon leads to less precipitation in the eastern China and Japan but more in the further north and northwest. However, the Indian monsoon circulation does not vary significantly while the precipitation over Arabian Sea is significantly promoted by the upward air motion. Change in water vapor sources of Indian and Pacific Oceans qualitatively explains the observed differences in stalagmite δ18O records, implying that these proxy changes are primarily controlled by the water vapor delivery from oceans, at least on the astronomical timescale.

Teleconnection between sea ice in the Barents Sea in June and the Silk Road, Pacific–Japan and East Asian rainfall patterns in August

In contrast to previous studies that have tended to focus on the influence of the total Arctic sea-ice cover on the East Asian summer tripole rainfall pattern, the present study identifies the Barents Sea as the key region where the June sea-ice variability exerts the most significant impacts on the East Asian August tripole rainfall pattern, and explores the teleconnection mechanisms involved. The results reveal that a reduction in June sea ice excites anomalous upward air motion due to strong near-surface thermal forcing, which further triggers a meridional overturning wave-like pattern extending to midlatitudes. Anomalous downward motion therefore forms over the Caspian Sea, which in turn induces zonally oriented overturning circulation along the subtropical jet stream, exhibiting the east–west Rossby wave train known as the Silk Road pattern. It is suggested that the Bonin high, a subtropical anticyclone predominant near South Korea, shows a significant anomaly due to the eastward extension of the Silk Road pattern to East Asia. As a possible descending branch of the Hadley cell, the Bonin high anomaly ultimately triggers a meridional overturning, establishing the Pacific–Japan pattern. This in turn induces an anomalous anticyclone and cyclone pair over East Asia, and a tripole vertical convection anomaly meridionally oriented over East Asia. Consequently, a tripole rainfall anomaly pattern is observed over East Asia. Results from numerical experiments using version 5 of the Community Atmosphere Model support the interpretation of this chain of events.

Enhancement of orographic precipitation in Jeju Island during the passage of Typhoon Khanun (2012)

Typhoon Khanun caused over 226mm of accumulated rainfall for 6h (0700 to 1300 UTC), localized around the summit of Mt. Halla (height 1950m), with a slanted rainfall pattern to the northeast. In this study, we investigated the enhancement mechanism for precipitation near the mountains as the typhoon passed over Jeju Island via dual-Doppler radar analysis and simple trajectory of passive tracers using a retrieved wind field. The analysis of vertical profiles of the mountain region show marked features matching the geophysical conditions. In the central mountain region, a strong wind (≥7ms−1) helps to lift low-level air up the mountain. The time taken for lifting is longer than the theoretical time required for raindrop growth via condensation. The falling particles (seeder) from the upper cloud were also one of the reasons for an increase in rainfall via the accretion process from uplifted cloud water (feeder). The lifted air and falling particles both contributed to the heavy rainfall in the central region. In contrast, on the leeward side, the seeder-feeder mechanism was important in the formation of strong radar reflectivity. The snow particles (above 5km) were accelerated by strong downward winds (≤−6ms−1). Meanwhile, the nonlinear jumping flow (hydraulic jump) raised feeders (shifted from the windward side) to the upper level where particles fall. To support these development processes, a numerical simulation using cloud-resolving model theoretically carried out. The accreting of hydrometeors may be one of the key reasons why the lee side has strong radar reflectivity, and a lee side weighted rainfall pattern even though lee side includes no strong upward air motion.

Trends in upper tropospheric water vapour over the Tibetan Plateau from remote sensing

Water vapour in the upper troposphere is the dominant greenhouse gas and provides a large feedback mechanism for amplifying climate change. However, lack of high elevation observations has limited our understating of its long term variability. In this study, the homogenized time series of the upper tropospheric water vapour (UTWV) brightness temperature (BT) over the Tibetan Plateau (TP) during 1979–2012, developed through inter-satellite calibration of high-resolution infrared radiation sounder (HIRS) channel 12 clear-sky measurements, is examined. The HIRS UTWV BT above the TP is increasing (drying), with an annual rate of 0.6 K decade−1 (p < 0.05), with the largest increases above the western TP. On a seasonal basis, HIRS UTWV BT shows only slight changes during 1979–1995, but rapidly increases from 1996 to 2012. Thus, drying is concentrated during recent decades, consistent with reduced water vapour flux and relative humidity. The time series of HIRS UTWV BT is correlated with a Mongolian geopotential height index at 400 hPa and the South Asian summer monsoon index derived from National Centers for Environmental Prediction/National Center for Atmospheric Research reanalysis. Thus atmospheric circulation anomalies are a control of changes in UTWV. In summer, increasing horizontal divergence at 400 hPa has suppressed the upward motion of air from the lower to the upper troposphere, reducing conveyance of sensible heat to the upper troposphere and contributing to the drying observed.

Association of Indian Ocean ITCZ Variations with the Arctic Oscillation during Boreal Winter

AbstractIn this study, the authors analyzed the associations between the Arctic Oscillation (AO) and the tropical Indian Ocean (TIO) intertropical convergence zone (ITCZ) in boreal winter for the period 1979-2009. A statistically significant AO-TIO ITCZ linkage was found. The ITCZ vertical air motion is significantly associated with the AO, with upward (downward) air motion corresponding to the positive (negative) AO phase. The Arabian Sea anticyclone plays a crucial role in linking the AO and the TIO ITCZ. The Arabian Sea vorticity is strongly linked to high-latitude disturbances in conjunction with jet stream waveguide effects of disturbance trapping and energy dispersion. During positive (negative) AO years, the Arabian Sea anticyclone tends to be stronger (weaker). The mean vorticity over the Arabian Sea, averaged from 850 hPa to 200 hPa, has a significant negative correlation with AO (r = .0.63). The anomalous anticyclone over the Arabian Sea brings stronger northeastern winds, which enhance the ITCZ...

Changes in water vapor transports of the ascending branch of the tropical circulation

[2] Recent and future changes in the statistical characteristics of the tropical atmospheric circulation (TAC) pattern and associated changes in the tropical hydrological cycle do not only locally affect the weather properties in the tropical areas but they have an influence on the extratropical regions. The general TAC pattern consists of convective regions of upward, ascending air movement (ASC) and of regions of downward, descending air motion (DESC), with low‐level flow into ASC and midlevel outflow into DESC commonly referred to as the Hadley Cell circulation. Along with the upward air motion, ASC contains most of the tropical precipitation and in its annual cycle by and large follows the Sun’s zenith. Part of the water vapor originates from evaporation in areas close by, but additionally large amounts of water are transported by atmospheric movements from DESC, causing a largely positive tropical water balance (precipitation‐evaporation) at the cost of the dry subtropics. A number of recent studies have addressed past and possible future changes in the moisture budget or in other components of the hydrological cycle over the tropics or over parts of the tropics. An increase in low‐level atmospheric water vapor of 7% per degree of warming is derived from theoretical considerations (Clausius‐Clapeyron relation, e.g., Wentz and Schabel[2000]; Trenberth et al. [2003]; Held and Soden

Sensitivity studies on the impacts of Tibetan Plateau snowpack pollution on the Asian hydrological cycle and monsoon climate

Abstract. The Tibetan Plateau (TP) has long been identified to be critical in regulating the Asian monsoon climate and hydrological cycle. In this modeling study a series of numerical experiments with a global climate model are designed to simulate radiative effect of black carbon (BC) and dust in snow, and to assess the relative impacts of anthropogenic CO2 and carbonaceous particles in the atmosphere and snow on the snowpack over the TP and subsequent impacts on the Asian monsoon climate and hydrological cycle. Simulations results show a large BC content in snow over the TP, especially the southern slope. Because of the high aerosol content in snow and large incident solar radiation in the low latitude and high elevation, the TP exhibits the largest surface radiative flux changes induced by aerosols (e.g. BC, Dust) in snow compared to any other snow-covered regions in the world. Simulation results show that the aerosol-induced snow albedo perturbations generate surface radiative flux changes of 5–25 W m−2 during spring, with a maximum in April or May. BC-in-snow increases the surface air temperature by around 1.0 °C averaged over the TP and reduces spring snowpack over the TP more than pre-industrial to present CO2 increase and carbonaceous particles in the atmosphere. As a result, runoff increases during late winter and early spring but decreases during late spring and early summer (i.e. a trend toward earlier melt dates). The snowmelt efficacy, defined as the snowpack reduction per unit degree of warming induced by the forcing agent, is 1–4 times larger for BC-in-snow than CO2 increase during April–July, indicating that BC-in-snow more efficiently accelerates snowmelt because the increased net solar radiation induced by reduced albedo melts the snow more efficiently than snow melt due to warming in the air. The TP also influences the South (SAM) and East (EAM) Asian monsoon through its dynamical and thermal forcing. Simulation results show that during boreal spring aerosols are transported by southwesterly, causing some particles to reach higher altitude and deposit to the snowpack over the TP. While BC and Organic Matter (OM) in the atmosphere directly absorb sunlight and warm the air, the darkened snow surface polluted by BC absorbs more solar radiation and increases the skin temperature, which warms the air above through sensible heat flux. Both effects enhance the upward motion of air and spur deep convection along the TP during the pre-monsoon season, resulting in earlier onset of the SAM and increase of moisture, cloudiness and convective precipitation over northern India. BC-in-snow has a more significant impact on the EAM in July than CO2 increase and carbonaceous particles in the atmosphere. Contributed by the significant increase of both sensible heat flux associated with the warm skin temperature and latent heat flux associated with increased soil moisture with long memory, the role of the TP as a heat pump is elevated from spring through summer as the land-sea thermal contrast increases to strengthen the EAM. As a result, both southern China and northern China become wetter, but central China (i.e. Yangtze River Basin) becomes drier – a near-zonal anomaly pattern that is consistent with the dominant mode of precipitation variability in East Asia. The snow impurity effects reported in this study likely represent some upper limits as snowpack is remarkably overestimated over the TP due to excessive precipitation. Improving the simulation of precipitation and snowpack will be important for improved estimates of the effects of snowpack pollution in future work.