Black carbon (BC), which is one of the highly absorbing capacities of solar radiation, reduces albedo of atmospheric aerosol. BC along with fine particulate matters (PM2.5), which play crucial role ...in climate and health, was monitored online for an entire year of 2011 at an urban megacity of Delhi, situated in the northern part of India. Daily mass concentration of BC varies from 0.9 to 25.5μgm−3, with an annual mean of 6.7±5.7μgm−3 displayed clear monsoon minima and winter maxima; however, PM2.5 concentration was ranging from 54.3 to 338.7μgm−3, with an annual mean of 122.3±90.7μgm−3. BC typically peaked between 0800 and 1000 LST and again between 2100 and 2300 LST, corresponding to the morning and evening traffic combined with the ambient meteorological effect. During summer and monsoon, the BC concentrations were found less than 5μgm−3; however, the highest concentrations occurred during winter in segments from <5 to >10μgm−3. In over all study, the BC mass concentration was accounted for ~6% of the total PM2.5 mass, with a range from 1.0% to 14.3%. The relationship between meteorological parameters and BC mass concentrations was studied and a clear inverse relationship (r=−0.53) between BC and wind speed was observed. Relation between visibility and BC mass concentrations was also significantly negative (−0.81), having relatively higher correlation during post-monsoon (−0.85) and winter (−0.78) periods and lower during summer (−0.45) and monsoon (−0.54) periods. The mixed layer depths (MLDs) were found to be shallower during post monsoon (379m) and winter (335m) as compared during summer (1023m) and monsoon (603m). The study indicated that during post-monsoon season, the impact of biomass burning is higher as compared to combustion of fossil fuels. Results are well associated with the rapid growth of anthropogenic emissions and ambient meteorological conditions over the station.
► Yearlong real-time measurement of BC and PM2.5 was carried out over Delhi. ► BC was accounted for ~6% to the total PM2.5 mass, with a range of 1 to 14%. ► The correlation among WS and visibility with BC was found to be negative.
The optical and radiative characteristics of water-soluble and carbonaceous aerosol species in the PM2.5 samples were examined for a representative megacity over the Indo-Gangetic Basin (IGB). ...Aerosol optical and radiative transfer models were used to extract sulphate (SO4), nitrate (NO3), organic carbon (OC) and elemental carbon (EC) from the observations done in 2012. Initial results suggest that the mass concentration of OC dominated over other species, but impacts on optical characteristics were mostly due to the SO4 aerosols. Further, EC shows relatively large impact on radiative forcing. The aerosol optical depth (AOD) at 500 nm for SO4, NO3, EC and OC was found to be contributing ~36%, 20%, 27% and 9%, respectively in the total AOD value (0.61 ± 0.18) during the entire study period. The single scattering albedo (SSA) for SO4 and NO3 was high and suggested their scattering nature; however, being the highly absorbing species, EC was found to show the lowest values of SSA during the study period. SSA for OC was, however, ~0.70, which was found to show the second highest warming species in the atmosphere with contribution of ~10%, after EC, which caused the highest warming (~70%), to the total atmospheric forcing.
•Optical and radiative characteristics of aerosol species of PM2.5 samples were examined.•The SO4 contributed highest (~36%) to the total AOD and lowest (~9%) for OC.•EC contributed highest to the total ADRFATM, though has lowest contribution to the PM2.5.•OC is the second highest contributor (~10%) as warming species to the total ADRFATM.
The microphysics behind the formation of rain droplets is an important feature influencing orographic precipitation at any location. The raindrop microphysics were determined for the precipitation in ...Mahabaleshwar, the orographic region of the Western Ghats in the Indian subcontinent, using Joss–Waldvogel Disdrometer (JWD) observational data for the period from 2013 to 2019. Smaller (< 1 mm) rain droplets were found to be dominant in monsoon seasons, while in the pre-monsoon and post-monsoon, a higher concentration of medium-sized (1–3 mm) and larger (> 3 mm) rain droplets were observed. In each season, the peak rain droplet concentration moved toward giant rain droplets with increasing rain rate. The probability density function of mass-weighted mean diameter (D
m
), normalized-intercept parameter (log
10
N
w
), rain rate (log
10
R), liquid water content (log
10
W), shape parameter (
µ
), and slope parameter (
Λ
) indicate a clear distinction in all three seasons. High D
m
and lower log
10
N
w
mean values were observed during the convective precipitation, while the opposite was observed during the stratiform rainfall of each season, except for the post-monsoon convective precipitation. Monsoon rainfall of both convective and stratiform nature had the lowest D
m
and highest log
10
N
w
compared to the respective cloud structure of pre-monsoon and post-monsoon. The D
m
and log
10
N
w
values in post-monsoon stratiform rain lay between the values observed in the monsoon and post-monsoon seasons. At the same time, the convective precipitation in the post-monsoon had the highest D
m
value, with a larger log
10
N
w
than the pre-monsoon convective precipitation. A unique µ-Λ quadratic equation was also determined for the pre-monsoon, monsoon, and post-monsoon season rain events.
Timely identification of individuals "at-risk" for myopia progression is the leading requisite for myopia practice as it aids in the decision of appropriate management. This study aimed to develop ...'myopia progression risk assessment score' (MPRAS) based on multiple risk factors (10) to determine whether a myope is "at-risk" or "low-risk" for myopia progression. Two risk-score models (model-1: non-weightage, model-2: weightage) were developed. Ability of MPRAS to diagnose individual "at-risk" for myopia progression was compared against decision of five clinicians in 149 myopes, aged 6-29 years. Using model-1 (no-weightage), further 7 sub-models were created with varying number of risk factors in decreasing step-wise manner (1a: 10 factors to 1g: 4 factors). In random eye analysis for model-1, the highest Youden's J-index (0.63-0.65) led to the MPRAS cut-off score of 41.50-43.50 for 5 clinicians with a sensitivity ranging from 78 to 85% and specificity ranging from 79 to 87%. For this cut-off score, the mean area under the curve (AUC) between clinicians and the MPRAS model ranged from 0.89 to 0.90. Model-2 (weighted for few risk-factors) provided similar sensitivity, specificity, and AUC. Sub-model analysis revealed greater AUC with high sensitivity (89%) and specificity (94%) in model-1g that has 4 risk factors compared to other sub-models (1a-1f). All the MPRAS models showed good agreement with the clinician's decision in identifying individuals "at-risk" for myopia progression.
This study investigates the projected changes in the upper troposphere and lower stratosphere (UTLS) water vapor over the Asian summer monsoon (ASM) region based on satellite records, numerical ...simulations using variable-resolution global climate model focused over south Asia (HIST-natural and anthropogenic forcing in the historical period, and FUT-following RCP4.5 in future), and Coupled Model Intercomparison Project Phase 5 (CMIP5) datasets. The simulations generally reproduced the seasonal cycle in the UTLS water vapor and regional water vapor maximum. With progressive warming in future, excessive upper tropospheric moistening is noted over the ASM region in far-future (2070–2095) climate against the HIST climate (1980–2005) with water vapor mixing ratio increasing to ~ 7.5 ppmv relative to ~ 5 ppmv noted in the HIST. It is further noted that projected changes in water vapor are linked to anomalous warming (~ 1–4 K) in the upper tropospheric layers juxtaposed with zonally elongated ASM anticyclone and enhanced water vapor flux divergence by amplifications in rotational winds. Further, the simulations indicate robust increase in ASM upper tropospheric water vapor as compared to those at mid- and lower- troposphere in accordance with the Clausius–Clapeyron temperature dependence of moisture response to warming and amplified troposphere warming with altitude. A simple comparison between the ASM and the entire globe indicates that upper tropospheric water vapor-temperature relationship has a similar response, however, the projected variability in temperature and moisture is significantly larger (about twice) over the ASM region highlighting strong regional influence. Nonetheless, the projections indicate that ASM is a potential regional source in modulating UTLS water vapor budget in a warming climate.
Sun/sky radiometer observations over the Indo-Gangetic Basin (IGB) region during pre-monsoon (from April–June 2009) have been processed to analyze various aerosol characteristics in the central and ...eastern IGB region, represented by Kanpur and Gandhi College, respectively, and their impacts on climate in terms of radiative forcing. Monthly mean aerosol optical depth (AOD at 500 nm) and corresponding Angstrom Exponent (AE at 440–870 nm, given within the brackets) was observed to be about 0.50 (0.49) and 0.51 (0.65) in April, 0.65 (0.74) and 0.67 (0.91) in May and 0.69 (0.45) and 0.77 (0.71) in June at Kanpur and Gandhi College, respectively. Results show a positive gradient in AOD and AE from central to eastern IGB region with the advancement of the pre-monsoon, which may be caused due to diverse geographical location of the stations having different meteorological conditions and emission sources. Relatively lower SSA was observed at the eastern IGB (0.89) than the central IGB (0.92) region during the period, which suggests relative dominance of absorbing aerosols at the eastern IGB as compared to central IGB region. The absorbing aerosol optical properties over the station suggest that the atmospheric absorption over central IGB region is mainly due to dominance of coarse-mode dust particles; however, absorption over eastern IGB region is mainly due to dominance of fine-particle pollution. The derived properties from sun/sky radiometer during pre-monsoon period are used in a radiative-transfer model to estimate aerosol radiative forcing at the top-of-the atmosphere (TOA) and at the surface over the IGB region. Relatively large TOA and surface cooling was observed at the eastern IGB as compared to the central IGB region. This translates into large heating of the atmosphere ranging from 0.45 to 0.55 K day−1 at Kanpur and from 0.45 to 0.59 K day−1 at Gandhi College.
The precipitation characteristics of tropical cyclone (TC) formed over the Arabian Sea during the onset phase of the Indian summer monsoon (i.e., late‐May and early‐June months) and in the ...post‐monsoon season were investigated during the period from 2014 to 2021 using the Global Precipitation Measurement (GPM) satellite level 2 V07 data. For the cyclonic precipitation, 2‐D frequency distribution between liquid water content (LWC) and non‐liquid water content, that is, ice water content (IWC) shows significant variation with the rain type and season. A large proportion of rain droplets are within the LWC (IWC) range of 0–800 (0–350) g/m2 for the stratiform precipitation of TCs in both seasons. The average value of the mass‐weighted mean diameter (Dm), for the stratiform and convective precipitation at 2 km above the mean sea level in the monsoon (post‐monsoon) season is 1.29 (1.27) mm and 1.47 (1.31) mm, respectively. A gradual decrease in the normalized intercept parameters (Nw) is found to occur with an increase in Dm, irrespective of cloud type and season. There is an enormously high concentration of supercooled liquid and ice particles observed above the melting layer during the convection precipitation in both seasons. In the stratiform cyclonic cloud, the contribution of the collision‐coalescence and breaking‐up process is about 36.62% (47.58%) and 52.52% (41.52%) during the monsoon (post‐monsoon) season. However, the collision‐coalescence process (63.45% in monsoon and 70.2% in post‐monsoon) is acting as dominating microphysical process in the convective precipitation as compared to the break‐up process.
Plain Language Summary
Tropical cyclone, a natural hazard causing significant economic loss and human life in the coastal region. As there is substantial improvement in forecast skill of the tropical cyclone movement and region of landfall, while prediction of the tropical cyclone's intensity is still challenging. The knowledge about the precipitation characteristics of the cyclonic cloud is helpful to improve the intensity of the tropical cyclone through the parameterization in the numerical models. For this, we study the microphysical characteristics of the tropical cyclone formed in the Arabian Sea.
Key Points
The cyclonic rainfall characteristics were investigated over the Arabian Sea using Global Precipitation Measurement‐dual‐frequency precipitation radar
Tropical cyclone formed during the monsoon onset phase, characterized with high fraction of intense rain rate, strong reflectivity and bigger raindrops
The contribution of collision‐coalescence (break‐up) is significantly high in convective (stratiform) rain
Heterogeneity amidst healthy individuals at genomic level is being widely acknowledged. This, in turn, is modulated by differential response to environmental cues and treatment regimens, ...necessitating the need for stratified/personalized therapy. We intend to understand the molecular determinants of Ayurvedic way (ancient Indian system of medicine) of endo-phenotyping individuals into distinct constitution types termed "
which forms the basis of personalized treatment. In this study, we explored and analyzed the healthy human gut microbiome structure within three predominant
groups from a genetically homogenous cohort to discover differentially abundant taxa, using 16S rRNA gene based microbial community profiling. We found Bacteroidetes and Firmicutes as major gut microbial components in varying composition, albeit with similar trend across
. Multiple species of the core microbiome showed differential abundance within
types, with gender specific signature taxons. Our study reveals that despite overall uniform composition of gut microbial community, healthy individuals belonging to different
groups have enrichment of specific bacteria. It highlights the importance of
based endo-phenotypes to explain the variability amongst healthy individuals in gut microbial flora that have important consequences for an individual's health, disease and treatment.
The mass concentration of carbonaceous species, organic carbon (OC), and elemental carbon (EC) using a semicontinuous thermo-optical EC-OC analyzer, and black carbon (BC) using an Aethalometer were ...measured simultaneously at an urban mega city Delhi in Ganga basin from January 2011 to May 2012. The concentrations of OC, EC, and BC exhibit seasonal variability, and their concentrations were ∼2 times higher during winter (OC 38.1 ± 17.9 μg m
−3
, EC 15.8 ± 7.3 μg m
−3
, and BC 10.1 ± 5.3 μg m
−3
) compared to those in summer (OC 14.1 ± 4.3 μg m
−3
, EC 7.5 ± 1.5 μg m
−3
, and BC 4.9 ± 1.5 μg m
−3
). A significant correlation between OC and EC (
R
= 0.95,
n
= 232) indicate their common emission sources with relatively lower OC/EC ratio (range 1.0–3.6, mean 2.2 ± 0.5) suggests fossil fuel emission as a major source of carbonaceous aerosols over the station. On average, mass concentration of EC was found to be ∼38 % higher than BC during the study period. The measured absorption coefficient (b
abs
) was significantly correlated with EC, suggesting EC as a major absorbing species in ambient aerosols at Delhi. Furthermore, the estimated mass absorption efficiency (σ
abs
) values are similar during winter (5.0 ± 1.5 m
2
g
−1
) and summer (4.8 ± 2.8 m
2
g
−1
). Significantly high aerosol loading of carbonaceous species emphasize an urgent need to focus on air quality management and proper impact assessment on health perspective in these regions.
Apomixis is a method of reproduction to generate clonal seeds and offers tremendous potential to fix heterozygosity and hybrid vigor. The process of apomictic seed development is complex and ...comprises three distinct components, viz., apomeiosis (leading to formation of unreduced egg cell), parthenogenesis (development of embryo without fertilization) and functional endosperm development. Recently, in many crops, these three components are reported to be uncoupled leading to their partitioning. This review provides insight into the recent status of our understanding surrounding partitioning apomixis components in gametophytic apomictic plants and research avenues that it offers to help understand the biology of apomixis. Possible consequences leading to diversity in seed developmental pathways, resources to understand apomixis, inheritance and identification of candidate gene(s) for partitioned components, as well as contribution towards creation of variability are all discussed. The potential of
, an aposporous crop, is also discussed as a model crop to study partitioning principle and effects. Modifications in cytogenetic status, as well as endosperm imprinting effects arising due to partitioning effects, opens up new opportunities to understand and utilize apomixis components, especially towards synthesizing apomixis in crops.
PDF
