GAJANAN AHER - Academia.edu (original) (raw)

Papers by GAJANAN AHER

Aerosol and Air Quality Research

Atmospheric aerosol characterization experiments were conducted, for the first time, over AC-Ahme... more Atmospheric aerosol characterization experiments were conducted, for the first time, over AC-Ahmednagar, a semi-urban location in southwest India, using a multi-spectral solar radiometer from January 2016 to May 2018. The MODIS/Terra retrieved Level-2 daily swath AOD550 nm data sets during 2011-2021 were also used to infer long-term behaviour of columnar aerosols at AC-Ahmednagar. The daily-averaged, Microtops II Sun photometer measured AOD500 nm and AOD1020 nm and MODIS retrieved AOD550 nm reveal a discernible wide spectrum of variability in their magnitudes. Magnitude-wise, AODs at both the wavelengths depict an increasing trend of about 0.05 year-1 (AOD500 nm) and 0.03 year-1 (AOD1020 nm). However, MODIS AOD550 nm illustrates statistically insignificant increasing trend of about 0.007 year-1. Microtops II Sun photometer derived Angstrom exponent (AE) depicts a noticeable day-today variability with respect to its overall mean value (1.06 ± 0.30) indicating the presence of diverse-sized aerosols. The AOD500 nm against AE440-870 nm contour density map analysis qualitatively characterizes different aerosol types prevalent in the atmospheric column. The weighted PSCF (WPSCF)

Asian Journal of Atmospheric Environment

Aerosol Science and Engineering, 2022

International Journal of Remote Sensing, 2018

Multi-year Aerosol Robotic Network (AERONET) direct Sun retrieved and inversion algorithm derived... more Multi-year Aerosol Robotic Network (AERONET) direct Sun retrieved and inversion algorithm derived aerosol products at a semi-arid, urban site, Jaipur (26.90°N, 75.80°E) and island observing site, Maldives Climate Observatory-Hanimaadhoo (MCO-Hanimaadhoo, 6.74°N, 73.17°E) are analysed to investigate heterogeneity in aerosol optical and microphysical properties. Results reveal the existence of a large seasonal diversity in the frequency distributions of aerosol optical depth (AOD 500 nm , AOD 1020 nm) and Ångström exponent (AE 440-870 nm) during different seasons at Jaipur and MCO-Hanimaadhoo. These are indicative of the advection of different aerosol types (viz., black carbon (BC) aerosol, organic aerosol, sulfate particle, dust, sea salt, nitrate particle, and mixtures thereof) from a variety of production mechanisms influenced by strong seasonal changes of anthropogenic activities as well as modulations induced by the climatic condition. The cumulative frequency analysis of the single scattering albedo (SSA) difference (i.e. ΔSSA = SSA 440 nm-SSA 1020 nm) shows that at Jaipur ΔSSA is predominantly negative (around 88% days) while at MCO-Hanimaadhoo it is positive (around 74% days). The positive and negative values of ΔSSA are respectively linked to a stronger absorption by BC mixed anthropogenic pollution aerosols at 1020 nm and to a stronger absorption by mineral dust containing iron oxide at 440 nm. The spectral behaviour of SSA, thus, facilitates investigation of the existence of iron oxide or BC in aerosols. The 'Bivariate Kernel density' plots of SSA versus fine-mode fraction (FMF) of AOD 440 nm /AE 440-870 nm reveal that at Jaipur the aerosol ensemble consists of coarse-mode particles (AE and FMF cluster in the range 0.2-0.4), a dominant category along with significant finemode and much less mixed category. At MCO-Hanimaadhoo finemode particle category (with FMF and AE cluster in the range 0.90-0.95 and 1.2-1.6 respectively) is the only dominant category. The persisting log-normal bimodal feature in aerosol volume size distribution (AVSD) is observed both at Jaipur and

Aerosol Science and Engineering, 2022

Aerosol and Air Quality Research, 2016

The present study evaluates the temporal variation of aerosol optical depth (AOD 500 nm) and the ... more The present study evaluates the temporal variation of aerosol optical depth (AOD 500 nm) and the Ångström parameters [viz., Ångström exponent (AE, α), Ångström turbidity coefficient (β) and second order Ångström exponent (α′)] at a tropical observing site, Pune (18°32′N; 73°49′E, 559 m AMSL) during 2008-15. Six-year means for winter and premonsoon seasons together are found to be 0.534 ± 0.13, 1.054 ± 0.27, 0.254 ± 0.08 and 0.167 ± 1.33 for AOD 500 nm , AE, β and α′ respectively. Average month-to-month variability of AOD 500 nm , AE, β and α′ during 2008-15 depicts seasonal cycle with strong departures with respect to long-term means. Frequency distributions for AOD, AE and β are positively skewed (skewness = 0.77, 0.32 and 1.14 respectively) while it is negatively skewed for α′ (skewness =-0.18). Analysis of AE difference, curvature parameter difference (α 2-α 1) and AOD 500 nm-AE 440-870 nm contour density map reveals that the aerosol ensemble at Pune consists of four aerosol types viz., UI (urban/industrial), CM (clear maritime), DD (desert dust) and MT (mixed type). Their relative magnitudes, however, differ during winter and pre-monsoon seasons. Thus, the contour density map shows dominance of UI and relatively less occurrence of MT type aerosols during winter. In pre-monsoon, however, the aerosol scenario is driven by MT type aerosol although UI and DD type aerosols show their remarkable existence.

Aerosol Science and Engineering

The MODerate Resolution Imaging Spectroradiometer (MODIS) retrieved (2009–2015) aerosol and cloud... more The MODerate Resolution Imaging Spectroradiometer (MODIS) retrieved (2009–2015) aerosol and cloud products over South-Central India, including adjoining coastal areas, were quantitatively analyzed to explore aerosol–cloud interaction and to estimate aerosol indirect effect (AIE). The spatial distribution of aerosol optical depth (AOD) showed high AOD 550 nm (~ 0.7) over the northern India and is attributed to the long- and short-range transport of desert dust aerosols, dense population, and industrialization. The mean seasonal AOD 550 nm over region decreases from (0.55 ± 0.11) to (0.45 ± 0.05) and to (0.39 ± 0.04) for monsoon, post-monsoon, and winter seasons, respectively. The western Indian regions, particularly Pune and Jaipur, showed higher mean AOD 500 nm as compared to other cities. The positive correlation of aerosol indirect effect (AIE) with AOD for Pune and Pondicherry through pre- as well post- monsoon seasons for all cities except Pondicherry is ascribed to hygroscopic aerosol particulate growth. The aerosol size spectra undergo significant transformation from dominant high accumulation-mode during September–February months [with Angström exponent (AE) > 1.0] to dominant augmented coarse-mode (AE < 1.0) through March to June–July period. The AOD 500 nm -to-cloud fraction (CF) correlation coefficients range between 0.05 and 0.46 for coastal region, while for Jaipur, Pune, and overall study region, the CFs are 0.53, 0.65, and 0.75, respectively. The pre-monsoon months recorded lower (0.4–0.6 µm) cloud effective radii values than monsoon season (0.8–1.3 µm). The AOD-to-cloud liquid water path correlations for Goa and Pune (0.30–0.48) are higher than other cities (0.01–0.19). The AIE average values for metropolitan, semi-arid, coastal, high-altitude sites, and overall study region were found to be − 0.168, − 0.025, − 0.104, − 0.101, and − 0.128, respectively. There occurs a noticeable negative AIE for three categories (viz., Metropolitan, coastal, and high-altitude station), while for semi-arid category, there exists a prominent Twomey (positive AIE) effect.

Journal of Science and Technology in Civil Engineering (STCE) - NUCE, Aug 30, 2018

To understand the dynamics of aerosols and their associated influence on regional and global clim... more To understand the dynamics of aerosols and their associated influence on regional and global climatic conditions requires the knowledge of spatial and temporal distributions of aerosols on regional and global scales. In this study, the satellite-based MODIS AODs retrievals level 2 products from Terra (MOD04-10 km) and Aqua (MYD04-10 km) satellites were inter-compared with the ground-based AERONET AODs (level 2) over Nghia Do station located in an urban area of Hanoi city, Vietnam for the period of 2010-2016. The Terra AODs showed good-match with the ground-based AODs measurements (slope = 0.830, intercept = 0.099, RMSE = 0.260, R 2 = 0.673, and RMB = 0.970). However, the Aqua AODs expressed systematically the underestimation of AERONET AODs (slope = 0.556, intercept = 0.184, RMSE = 0.390, R 2 = 0.408, and RMB = 0.810). All MODIS AODs indicated the moderate correlation with AERONET AODs (slope = 0.683, intercept = 0.147, RMSE = 0.330, R 2 = 0.520, and RMB = 0.890). Although MODIS AODs followed well the monthly variations of AERONET AODs, the relatively high discrepancy between MODIS and AERONET AODs could be observed during the winter months.

MODerate Resolution Imaging Spectroradiometer (MODIS) retrieved aerosol and cloud products at the... more MODerate Resolution Imaging Spectroradiometer (MODIS) retrieved aerosol and cloud products at the nine selected stations over Western Himalayan and Deccan Plateau regions were inferred to bring out their salient features and to investigate aerosol–cloud interaction. Annually, Ångström exponent (AE) decreases with aerosol optical depth (AOD) while in winter it increases with AOD at most of the stations. Results bring out positive and/or negative association between AOD and almost all the cloud parameters over the selected stations. Aerosol indirect effect (AIE) is quantified for fixed liquid water path (LWP) bins ranging from 1 to 350 g/m2 at an interval of 25 g/m2 for three categories of stations, viz., CAT‐H, CAT‐M, and CAT‐L based on heavy, moderate, and low aerosol loading, respectively. AIE is negative at CAT‐H (−0.04 ± 0.14), while it is positive at CAT‐M (0.01 ± 0.07) and CAT‐L (0.10 ± 0.48). During winter, negative AIE has been observed for all three categories. In pre‐ monso...

aaqr.org

Simultaneous measurements of aerosol optical depth and incoming global solar flux were carried ou... more Simultaneous measurements of aerosol optical depth and incoming global solar flux were carried out with a MICROTOPS-II Sunphotometer and Eppley Precision Spectral Pyranometer over Nowrosjee Wadia College (NWC, Pune) as the nodal centre, and at Pune University (PU) and IUCAA Girwali Observatory (IGO), in a field campaign mode during December 2010-May 2011. Data was analyzed to determine the surface shortwave (SW) aerosol direct radiative forcing (ADRF, ∆F per unit 0.1 AOD) and to study the characteristics of the aerosols. The results indicate that ADRF shows significant day-today variability and co-varies with AOD. The cause of the day-today variation in ADRF is an anticorrelation between ADRF/AOD, and differences in the daily maximum minus minimum RH and temperature. At NWC, ADRF ranges between-37.7 W/m 2 (highest) and-5.9 W/m 2 (lowest). For 500 nm, ADRF takes values in the range-17.3 ± 7.1 W/m 2 to-54.2 ± 5.5 W/m 2 at PU, whereas the corresponding values at IGO are-15.1 ± 2.1 W/m 2 and-36.6 ± 6.4 W/m 2. Monthly ADRF is at the minimum level in winter and maximum during the pre-monsoon period. The magnitude of AOD shows significant diurnal variability. In winter, the mean AOD diurnal percentage departure at 500 nm is positive in the morning and negative during the afternoon, and this is reversed in the pre-monsoon period. The diurnal cycle of AOD is related to the prevalent meteorological conditions, surface-based nocturnal temperature inversion in the atmospheric boundary layer (ABL), and influx of aerosols from different source regions.

Aerosols - Science and Case Studies, 2016

MODerate Resolution Imaging Spectroradiometer (MODIS) retrieved aerosol and cloud products at the... more MODerate Resolution Imaging Spectroradiometer (MODIS) retrieved aerosol and cloud products at the nine selected stations over Western Himalayan and Deccan Plateau regions were inferred to bring out their salient features and to investigate aerosol-cloud interaction. Annually, Ångström exponent (AE) decreases with aerosol optical depth (AOD) while in winter it increases with AOD at most of the stations. Results bring out positive and/or negative association between AOD and almost all the cloud parameters over the selected stations. Aerosol indirect effect (AIE) is quantified for fixed liquid water path (LWP) bins ranging from 1 to 350 g/m 2 at an interval of 25 g/m 2 for three categories of stations, viz., CAT-H, CAT-M, and CAT-L based on heavy, moderate, and low aerosol loading, respectively. AIE is negative at CAT-H (−0.04 ± 0.14), while it is positive at CAT-M (0.01 ± 0.07) and CAT-L (0.10 ± 0.48). During winter, negative AIE has been observed for all three categories. In premonsoon, the majority of LWP bins (86% at CAT-H and 60% at CAT-M) showed positive AIE, while about 71% of LWP bins indicted negative AIE at CAT-L. However, during monsoon about 63-71% of LWP bins showed negative AIE at these categories. Study elucidates the influence of factors like cloud type, cloud dynamics/thermodynamics on aerosol-cloud interactions.

Journal of Atmospheric and Solar-Terrestrial Physics

International Journal of Remote Sensing

Aerosol and Air Quality Research

Atmospheric aerosol characterization experiments were conducted, for the first time, over AC-Ahme... more Atmospheric aerosol characterization experiments were conducted, for the first time, over AC-Ahmednagar, a semi-urban location in southwest India, using a multi-spectral solar radiometer from January 2016 to May 2018. The MODIS/Terra retrieved Level-2 daily swath AOD550 nm data sets during 2011-2021 were also used to infer long-term behaviour of columnar aerosols at AC-Ahmednagar. The daily-averaged, Microtops II Sun photometer measured AOD500 nm and AOD1020 nm and MODIS retrieved AOD550 nm reveal a discernible wide spectrum of variability in their magnitudes. Magnitude-wise, AODs at both the wavelengths depict an increasing trend of about 0.05 year-1 (AOD500 nm) and 0.03 year-1 (AOD1020 nm). However, MODIS AOD550 nm illustrates statistically insignificant increasing trend of about 0.007 year-1. Microtops II Sun photometer derived Angstrom exponent (AE) depicts a noticeable day-today variability with respect to its overall mean value (1.06 ± 0.30) indicating the presence of diverse-sized aerosols. The AOD500 nm against AE440-870 nm contour density map analysis qualitatively characterizes different aerosol types prevalent in the atmospheric column. The weighted PSCF (WPSCF)

Asian Journal of Atmospheric Environment

Aerosol Science and Engineering, 2022

International Journal of Remote Sensing, 2018

Multi-year Aerosol Robotic Network (AERONET) direct Sun retrieved and inversion algorithm derived... more Multi-year Aerosol Robotic Network (AERONET) direct Sun retrieved and inversion algorithm derived aerosol products at a semi-arid, urban site, Jaipur (26.90°N, 75.80°E) and island observing site, Maldives Climate Observatory-Hanimaadhoo (MCO-Hanimaadhoo, 6.74°N, 73.17°E) are analysed to investigate heterogeneity in aerosol optical and microphysical properties. Results reveal the existence of a large seasonal diversity in the frequency distributions of aerosol optical depth (AOD 500 nm , AOD 1020 nm) and Ångström exponent (AE 440-870 nm) during different seasons at Jaipur and MCO-Hanimaadhoo. These are indicative of the advection of different aerosol types (viz., black carbon (BC) aerosol, organic aerosol, sulfate particle, dust, sea salt, nitrate particle, and mixtures thereof) from a variety of production mechanisms influenced by strong seasonal changes of anthropogenic activities as well as modulations induced by the climatic condition. The cumulative frequency analysis of the single scattering albedo (SSA) difference (i.e. ΔSSA = SSA 440 nm-SSA 1020 nm) shows that at Jaipur ΔSSA is predominantly negative (around 88% days) while at MCO-Hanimaadhoo it is positive (around 74% days). The positive and negative values of ΔSSA are respectively linked to a stronger absorption by BC mixed anthropogenic pollution aerosols at 1020 nm and to a stronger absorption by mineral dust containing iron oxide at 440 nm. The spectral behaviour of SSA, thus, facilitates investigation of the existence of iron oxide or BC in aerosols. The 'Bivariate Kernel density' plots of SSA versus fine-mode fraction (FMF) of AOD 440 nm /AE 440-870 nm reveal that at Jaipur the aerosol ensemble consists of coarse-mode particles (AE and FMF cluster in the range 0.2-0.4), a dominant category along with significant finemode and much less mixed category. At MCO-Hanimaadhoo finemode particle category (with FMF and AE cluster in the range 0.90-0.95 and 1.2-1.6 respectively) is the only dominant category. The persisting log-normal bimodal feature in aerosol volume size distribution (AVSD) is observed both at Jaipur and

Aerosol Science and Engineering, 2022

Aerosol and Air Quality Research, 2016

The present study evaluates the temporal variation of aerosol optical depth (AOD 500 nm) and the ... more The present study evaluates the temporal variation of aerosol optical depth (AOD 500 nm) and the Ångström parameters [viz., Ångström exponent (AE, α), Ångström turbidity coefficient (β) and second order Ångström exponent (α′)] at a tropical observing site, Pune (18°32′N; 73°49′E, 559 m AMSL) during 2008-15. Six-year means for winter and premonsoon seasons together are found to be 0.534 ± 0.13, 1.054 ± 0.27, 0.254 ± 0.08 and 0.167 ± 1.33 for AOD 500 nm , AE, β and α′ respectively. Average month-to-month variability of AOD 500 nm , AE, β and α′ during 2008-15 depicts seasonal cycle with strong departures with respect to long-term means. Frequency distributions for AOD, AE and β are positively skewed (skewness = 0.77, 0.32 and 1.14 respectively) while it is negatively skewed for α′ (skewness =-0.18). Analysis of AE difference, curvature parameter difference (α 2-α 1) and AOD 500 nm-AE 440-870 nm contour density map reveals that the aerosol ensemble at Pune consists of four aerosol types viz., UI (urban/industrial), CM (clear maritime), DD (desert dust) and MT (mixed type). Their relative magnitudes, however, differ during winter and pre-monsoon seasons. Thus, the contour density map shows dominance of UI and relatively less occurrence of MT type aerosols during winter. In pre-monsoon, however, the aerosol scenario is driven by MT type aerosol although UI and DD type aerosols show their remarkable existence.

Aerosol Science and Engineering

The MODerate Resolution Imaging Spectroradiometer (MODIS) retrieved (2009–2015) aerosol and cloud... more The MODerate Resolution Imaging Spectroradiometer (MODIS) retrieved (2009–2015) aerosol and cloud products over South-Central India, including adjoining coastal areas, were quantitatively analyzed to explore aerosol–cloud interaction and to estimate aerosol indirect effect (AIE). The spatial distribution of aerosol optical depth (AOD) showed high AOD 550 nm (~ 0.7) over the northern India and is attributed to the long- and short-range transport of desert dust aerosols, dense population, and industrialization. The mean seasonal AOD 550 nm over region decreases from (0.55 ± 0.11) to (0.45 ± 0.05) and to (0.39 ± 0.04) for monsoon, post-monsoon, and winter seasons, respectively. The western Indian regions, particularly Pune and Jaipur, showed higher mean AOD 500 nm as compared to other cities. The positive correlation of aerosol indirect effect (AIE) with AOD for Pune and Pondicherry through pre- as well post- monsoon seasons for all cities except Pondicherry is ascribed to hygroscopic aerosol particulate growth. The aerosol size spectra undergo significant transformation from dominant high accumulation-mode during September–February months [with Angström exponent (AE) > 1.0] to dominant augmented coarse-mode (AE < 1.0) through March to June–July period. The AOD 500 nm -to-cloud fraction (CF) correlation coefficients range between 0.05 and 0.46 for coastal region, while for Jaipur, Pune, and overall study region, the CFs are 0.53, 0.65, and 0.75, respectively. The pre-monsoon months recorded lower (0.4–0.6 µm) cloud effective radii values than monsoon season (0.8–1.3 µm). The AOD-to-cloud liquid water path correlations for Goa and Pune (0.30–0.48) are higher than other cities (0.01–0.19). The AIE average values for metropolitan, semi-arid, coastal, high-altitude sites, and overall study region were found to be − 0.168, − 0.025, − 0.104, − 0.101, and − 0.128, respectively. There occurs a noticeable negative AIE for three categories (viz., Metropolitan, coastal, and high-altitude station), while for semi-arid category, there exists a prominent Twomey (positive AIE) effect.

Journal of Science and Technology in Civil Engineering (STCE) - NUCE, Aug 30, 2018

To understand the dynamics of aerosols and their associated influence on regional and global clim... more To understand the dynamics of aerosols and their associated influence on regional and global climatic conditions requires the knowledge of spatial and temporal distributions of aerosols on regional and global scales. In this study, the satellite-based MODIS AODs retrievals level 2 products from Terra (MOD04-10 km) and Aqua (MYD04-10 km) satellites were inter-compared with the ground-based AERONET AODs (level 2) over Nghia Do station located in an urban area of Hanoi city, Vietnam for the period of 2010-2016. The Terra AODs showed good-match with the ground-based AODs measurements (slope = 0.830, intercept = 0.099, RMSE = 0.260, R 2 = 0.673, and RMB = 0.970). However, the Aqua AODs expressed systematically the underestimation of AERONET AODs (slope = 0.556, intercept = 0.184, RMSE = 0.390, R 2 = 0.408, and RMB = 0.810). All MODIS AODs indicated the moderate correlation with AERONET AODs (slope = 0.683, intercept = 0.147, RMSE = 0.330, R 2 = 0.520, and RMB = 0.890). Although MODIS AODs followed well the monthly variations of AERONET AODs, the relatively high discrepancy between MODIS and AERONET AODs could be observed during the winter months.

MODerate Resolution Imaging Spectroradiometer (MODIS) retrieved aerosol and cloud products at the... more MODerate Resolution Imaging Spectroradiometer (MODIS) retrieved aerosol and cloud products at the nine selected stations over Western Himalayan and Deccan Plateau regions were inferred to bring out their salient features and to investigate aerosol–cloud interaction. Annually, Ångström exponent (AE) decreases with aerosol optical depth (AOD) while in winter it increases with AOD at most of the stations. Results bring out positive and/or negative association between AOD and almost all the cloud parameters over the selected stations. Aerosol indirect effect (AIE) is quantified for fixed liquid water path (LWP) bins ranging from 1 to 350 g/m2 at an interval of 25 g/m2 for three categories of stations, viz., CAT‐H, CAT‐M, and CAT‐L based on heavy, moderate, and low aerosol loading, respectively. AIE is negative at CAT‐H (−0.04 ± 0.14), while it is positive at CAT‐M (0.01 ± 0.07) and CAT‐L (0.10 ± 0.48). During winter, negative AIE has been observed for all three categories. In pre‐ monso...

aaqr.org

Simultaneous measurements of aerosol optical depth and incoming global solar flux were carried ou... more Simultaneous measurements of aerosol optical depth and incoming global solar flux were carried out with a MICROTOPS-II Sunphotometer and Eppley Precision Spectral Pyranometer over Nowrosjee Wadia College (NWC, Pune) as the nodal centre, and at Pune University (PU) and IUCAA Girwali Observatory (IGO), in a field campaign mode during December 2010-May 2011. Data was analyzed to determine the surface shortwave (SW) aerosol direct radiative forcing (ADRF, ∆F per unit 0.1 AOD) and to study the characteristics of the aerosols. The results indicate that ADRF shows significant day-today variability and co-varies with AOD. The cause of the day-today variation in ADRF is an anticorrelation between ADRF/AOD, and differences in the daily maximum minus minimum RH and temperature. At NWC, ADRF ranges between-37.7 W/m 2 (highest) and-5.9 W/m 2 (lowest). For 500 nm, ADRF takes values in the range-17.3 ± 7.1 W/m 2 to-54.2 ± 5.5 W/m 2 at PU, whereas the corresponding values at IGO are-15.1 ± 2.1 W/m 2 and-36.6 ± 6.4 W/m 2. Monthly ADRF is at the minimum level in winter and maximum during the pre-monsoon period. The magnitude of AOD shows significant diurnal variability. In winter, the mean AOD diurnal percentage departure at 500 nm is positive in the morning and negative during the afternoon, and this is reversed in the pre-monsoon period. The diurnal cycle of AOD is related to the prevalent meteorological conditions, surface-based nocturnal temperature inversion in the atmospheric boundary layer (ABL), and influx of aerosols from different source regions.

Aerosols - Science and Case Studies, 2016

MODerate Resolution Imaging Spectroradiometer (MODIS) retrieved aerosol and cloud products at the... more MODerate Resolution Imaging Spectroradiometer (MODIS) retrieved aerosol and cloud products at the nine selected stations over Western Himalayan and Deccan Plateau regions were inferred to bring out their salient features and to investigate aerosol-cloud interaction. Annually, Ångström exponent (AE) decreases with aerosol optical depth (AOD) while in winter it increases with AOD at most of the stations. Results bring out positive and/or negative association between AOD and almost all the cloud parameters over the selected stations. Aerosol indirect effect (AIE) is quantified for fixed liquid water path (LWP) bins ranging from 1 to 350 g/m 2 at an interval of 25 g/m 2 for three categories of stations, viz., CAT-H, CAT-M, and CAT-L based on heavy, moderate, and low aerosol loading, respectively. AIE is negative at CAT-H (−0.04 ± 0.14), while it is positive at CAT-M (0.01 ± 0.07) and CAT-L (0.10 ± 0.48). During winter, negative AIE has been observed for all three categories. In premonsoon, the majority of LWP bins (86% at CAT-H and 60% at CAT-M) showed positive AIE, while about 71% of LWP bins indicted negative AIE at CAT-L. However, during monsoon about 63-71% of LWP bins showed negative AIE at these categories. Study elucidates the influence of factors like cloud type, cloud dynamics/thermodynamics on aerosol-cloud interactions.

Journal of Atmospheric and Solar-Terrestrial Physics

International Journal of Remote Sensing