Assessment of aerosols optical properties and radiative forcing over an Urban site in North-Western India

2016 ◽  
Vol 38 (10) ◽  
pp. 1232-1244 ◽  
Author(s):  
Vikram Mor ◽  
Rajesh Dhankhar ◽  
S. D. Attri ◽  
V. K. Soni ◽  
M. Sateesh ◽  
...  
Keyword(s):  
Optical Properties ◽  
Radiative Forcing ◽  
Urban Site ◽  
Western India ◽  
North Western

Variable monsoons and human adaptations: Archaeological and palaeoenvironmental records during the last 1400 years in north-western India

The Holocene ◽  
2020 ◽  
Vol 30 (9) ◽  
pp. 1332-1344
Author(s):  
Anil K Pokharia ◽  
Jeewan Singh Kharakwal ◽  
Shalini Sharma ◽  
Michael Spate ◽  
Deepika Tripathi ◽  
...  
Keyword(s):  
Climate Change ◽  
Ice Age ◽  
Future Climate Change ◽  
Urban Site ◽  
Western India ◽  
Monsoon Precipitation ◽  
Medieval Period ◽  
Drought Resistant ◽  
The Impact ◽  
North Western

We present the first systematic evaluation of the relationship between the archaeological and palaeoclimatic record from north-western India during the past millennium, from the urban site of Chandravati. The rarity of Medieval sites, systematic excavations and multi-disciplinary work in the subcontinent obscure the impact of two distinct climate anomalies − the ‘Medieval Warm Period’ (‘MWP’, 740 − 1150 CE), followed by the ‘Little Ice Age’ (‘LIA’, 1350 − 1850 CE). The finds from the archaeological site indicate the presence of winter and summer crops, suggesting the region was likely warm and mild humid during pre-Medieval period (ca. 600 − 800 CE). During Medieval times (between ca. 800 − 1300 CE), a diversification of the crop assemblage suggests that the region was under a warm and humid climate, corresponding to the ‘MWP’, driving increased monsoon precipitation. During the post-Medieval period (ca. 1350 − 1800 CE), drought-resistant millets and other summer pulse crops indicate the region probably experienced weak SW monsoon precipitation coinciding with globally recognised ‘LIA’. These interpretations are supported through phytolith data from the archaeological deposit broadly indicating two phases, the first being a period of diversified agricultural/anthropogenic activity (ca. 600 − 1350 CE), followed by a period dominated by drought-resistant crops (ca. 1350 − 1800 CE). Pollen data from a proximal lake corroborate the warm and humid phase ca. 800 − 1400 CE, with strong representation of warm−humid favouring tropical forest taxa, followed by non-arboreal indicators of a drier more open landscape ca. 1500 − 1800 CE. These environmental changes may have combined with other historic and institutional factors that led to the ultimate abandonment of the city. These changing cropping patterns, vegetation and cultural developments provide insight into past human response to climate change as well as important lessons for modern societies in exploring sustainable agricultural strategies to future climate change.

scholarly journals Assessment of regional aerosol radiative effects under the SWAAMI campaign – Part 2: Clear-sky direct shortwave radiative forcing using multi-year assimilated data over the Indian subcontinent

2020 ◽  
Vol 20 (22) ◽  
pp. 14237-14252
Author(s):  
Harshavardhana Sunil Pathak ◽  
Sreedharan Krishnakumari Satheesh ◽  
Krishnaswamy Krishna Moorthy ◽  
Ravi Shankar Nanjundiah
Keyword(s):  
Radiative Forcing ◽  
Regional Distribution ◽  
Indian Region ◽  
Western India ◽  
Surface Cooling ◽  
Gangetic Plain ◽  
Clear Sky ◽  
Atmospheric Warming ◽  
North Western ◽  
Aerosol Radiative

Abstract. Clear-sky, direct shortwave aerosol radiative forcing (ARF) has been estimated over the Indian region, for the first time employing multi-year (2009–2013) gridded, assimilated aerosol products, as an important part of the South West Asian Aerosol Monsoon Interactions (SWAAMI) which is a joint Indo-UK research field campaign focused at understanding the variabilities in atmospheric aerosols and their interactions with the Indian summer monsoon. The aerosol datasets have been constructed following statistical assimilation of concurrent data from a dense network of ground-based observatories and multi-satellite products, as described in Part 1 of this two-part paper. The ARF, thus estimated, is assessed for its superiority or otherwise over other ARF estimates based on satellite-retrieved aerosol products, over the Indian region, by comparing the radiative fluxes (upward) at the top of the atmosphere (TOA) estimated using assimilated and satellite products with spatiotemporally matched radiative flux values provided by CERES (Clouds and Earth's Radiant Energy System) single-scan footprint (SSF) product. This clearly demonstrated improved accuracy of the forcing estimates using the assimilated vis-à-vis satellite-based aerosol datasets at regional, subregional and seasonal scales. The regional distribution of diurnally averaged ARF estimates has revealed (a) significant differences from similar estimates made using currently available satellite data, not only in terms of magnitude but also the sign of TOA forcing; (b) the largest magnitudes of surface cooling and atmospheric warming over the Indo-Gangetic Plain (IGP) and arid regions from north-western India; and (c) negative TOA forcing over most parts of the Indian region, except for three subregions – the IGP, north-western India and eastern parts of peninsular India where the TOA forcing changes to positive during pre-monsoon season. Aerosol-induced atmospheric warming rates, estimated using the assimilated data, demonstrate substantial spatial heterogeneities (∼0.2 to 2.0 K d−1) over the study domain with the IGP demonstrating relatively stronger atmospheric heating rates (∼0.6 to 2.0 K d−1). There exists a strong seasonality as well, with atmospheric warming being highest during pre-monsoon and lowest during winter seasons. It is to be noted that the present ARF estimates demonstrate substantially smaller uncertainties than their satellite counterparts, which is a natural consequence of reduced uncertainties in assimilated vis-à-vis satellite aerosol properties. The results demonstrate the potential application of the assimilated datasets and ARF estimates for improving accuracies of climate impact assessments at regional and subregional scales.

scholarly journals Assessment of Regional Aerosol Radiative Effects under SWAAMI Campaign – PART 2: Clear-sky Direct Shortwave Radiative Forcing using Multi-year Assimilated Data

2020 ◽  
Author(s):  
Harshavardhana Sunil Pathak ◽  
Sreedharan Krishnakumari Satheesh ◽  
Krishnaswamy Krishna Moorthy ◽  
Ravi Shankar Nanjundiah
Keyword(s):  
Radiative Forcing ◽  
Regional Distribution ◽  
Radiant Energy ◽  
Indian Region ◽  
Western India ◽  
Surface Cooling ◽  
Clear Sky ◽  
Atmospheric Warming ◽  
North Western ◽  
Aerosol Radiative

Abstract. Clear-sky, direct shortwave Aerosol Radiative Forcing (ARF) has been estimated over the Indian region, for the first time employing multi-year (2009–2013) gridded, assimilated aerosol products. The aerosol datasets have been constructed following statistical assimilation of concurrent data from a dense network of ground-based observatories, and multi-satellite products, as described in Part-1 of this two-part paper. The ARF, thus estimated, are assessed for their superiority or otherwise over other ARF estimates based on satellite-retrieved aerosol products, over the Indian region, by comparing the radiative fluxes (upward) at Top of Atmosphere (TOA) estimated using assimilated products with spatio-temporally matched radiative flux values provided by CERES (Clouds and Earth's Radiant Energy System) Single Scan Footprint (SSF) product. This clearly demonstrated improved accuracy of the forcing estimates using the assimilated vis-a-vis satellite-based aerosol datasets; at regional, sub-regional and seasonal scales. The regional distribution of diurnally averaged ARF estimates has revealed (a) significant differences from similar estimates made using currently available satellite data, not only in terms of magnitude but also sign of TOA forcing; (b) largest magnitudes of surface cooling and atmospheric warming over IGP and arid regions from north-western India; and (c) negative TOA forcing over most parts of the Indian region, except for three sub-regions – the Indo-Gangetic plains (IGP), north-western India and eastern parts of peninsular India where the TOA forcing changes to positive during pre-monsoon season. Aerosol induced atmospheric warming rates, estimated using the assimilated data, demonstrate substantial spatial heterogeneities (~ 0.2 to 2.0 K day−1) over the study domain with the IGP demonstrating relatively stronger atmospheric heating rates (~ 0.6 to 2.0 K day−1). There exists a strong seasonality as well; with atmospheric warming being highest during pre-monsoon and lowest during winter seasons. It is to be noted that the present ARF estimates demonstrate substantially smaller uncertainties than their satellite counterparts, which is a natural consequence of reduced uncertainties in assimilated vis-a-vis satellite aerosol properties. The results demonstrate the potential application of the assimilated datasets and ARF estimates for improving accuracies of climate impact assessments at regional and sub-regional scales.

Gastrointestinal Protective Effect of Zizyphus xylopyrus (Retz) Willd Leaf Extract Against Indomethacin and HCl-EtOH Induced Ulcers

2019 ◽  
Vol 5 (2) ◽  
pp. 140-146
Author(s):  
Shweta Jain ◽  
Sourabh Jain ◽  
Nagendra S. Chauhan ◽  
Ankur Vaidya
Keyword(s):  
Protective Effect ◽  
Ethanolic Extract ◽  
Negative Control ◽  
Gastric Epithelium ◽  
Gastric Ulcers ◽  
Western India ◽  
Skin Infections ◽  
Ulcer Index ◽  
Digestive Disorders ◽  
North Western

Background: Zizyphus xylopyrus (Retz.) Willd. (Rhamnaceae) is a straggling shrub or a small tree, armed with spines, found throughout north western India, Pakistan and China. Methods: The aerial and root barks, leaves and fruits of Zizyphus species are used in medicine for the treatment of various diseases such as weakness, liver complaints, obesity, diabetes, skin infections, fever, diarrhea, insomnia and digestive disorders. Ethanolic extract of leaves of Zizyphus xylopyrus (Retz) Willd was prepared by solvent extraction and subjected to study the protective effect against Indomethacin and HCl-EtOH induced ulcer using Ranitidine (100 mg/kg) and Omeprazole (8 mg/kg) as standard respectively. Results: Histopathological lesions with marked disorientation of the gastric epithelium was observed in negative control, while extract treated rats showed a better protected mucosa with intact epithelium in comparison to standard treated rats. Ulcer index and percentage ulcer protection also represent protecting effects of the extract. Conclusion: Ethanolic extract of Z. xylopyrus (Retz) Willd leaves extract was found to be significantly protective against gastric ulcers.

scholarly journals Optical and Physical Properties of Atmospheric Aerosols over the Bay of Bengal during ICARB

2009 ◽  
Vol 66 (9) ◽  
pp. 2640-2658 ◽  
Author(s):  
Vijayakumar S. Nair ◽  
K. Krishna Moorthy ◽  
S. Suresh Babu ◽  
S. K. Satheesh
Keyword(s):  
Atmospheric Aerosols ◽  
Bay Of Bengal ◽  
Radiative Forcing ◽  
Latitudinal Gradients ◽  
Back Trajectory ◽  
Western India ◽  
Size Distributions ◽  
Average Mass ◽  
Scattering Coefficients ◽  
Vertical Heterogeneity

Abstract Simultaneous and collocated measurements of total and hemispherical backscattering coefficients (σ and β, respectively) at three wavelengths, mass size distributions, and columnar spectral aerosol optical depth (AOD) were made onboard an extensive cruise experiment covering, for the first time, the entire Bay of Bengal (BoB) and northern Indian Ocean. The results are synthesized to understand the optical properties of aerosols in the marine atmospheric boundary layer and their dependence on the size distribution. The observations revealed distinct spatial and spectral variations of all the aerosol parameters over the BoB and the presence of strong latitudinal gradients. The size distributions varied spatially, with the majority of accumulation modes decreasing from north to south. The scattering coefficient decreased from very high values (resembling those reported for continental/urban locations) in the northern BoB to very low values seen over near-pristine environments in the southeastern BoB. The average mass scattering efficiency of BoB aerosols was found to be 2.66 ± 0.1 m2 g−1 at 550 nm. The spectral dependence of columnar AOD deviated significantly from that of the scattering coefficients in the northern BoB, implying vertical heterogeneity in the aerosol type in that region. However, a more homogeneous scenario was observed in the southern BoB. Simultaneous lidar and in situ measurements onboard an aircraft over the ocean revealed the presence of elevated aerosol layers of enhanced extinction at altitudes of 1 to 3 km with an offshore extent of a few hundred kilometers. Back-trajectory analyses showed these layers to be associated with advection from west Asia and western India. The large spatial variations and vertical heterogeneity in aerosol properties, revealed by the present study, need to be included in the regional radiative forcing over the Bay of Bengal.

scholarly journals Aerosol radiative forcing over a tropical urban site in India

2004 ◽  
Vol 31 (12) ◽  
pp. n/a-n/a ◽  
Author(s):  
G. Pandithurai ◽  
R. T. Pinker ◽  
T. Takamura ◽  
P. C. S. Devara
Keyword(s):  
Radiative Forcing ◽  
Urban Site ◽  
Aerosol Radiative Forcing ◽  
Aerosol Radiative

Aerosol radiative forcing due to enhanced black carbon at an urban site in India

2002 ◽  
Vol 29 (18) ◽  
pp. 27-1-27-4 ◽  
Author(s):  
S. Suresh Babu ◽  
S. K. Satheesh ◽  
K. Krishna Moorthy
Keyword(s):  
Black Carbon ◽  
Radiative Forcing ◽  
Urban Site ◽  
Aerosol Radiative Forcing ◽  
Aerosol Radiative

Studies on the origin, evolution, and distribution of the Gramineae. III. The tribes of the subfamily Eragrostoideae

1960 ◽  
Vol 8 (3) ◽  
pp. 256 ◽  
Author(s):  
W Hartley ◽  
C Slater
Keyword(s):  
Wide Distribution ◽  
Western India ◽  
Distribution Maps ◽  
Winter Temperatures ◽  
Close Relationship ◽  
Hot Arid Climate ◽  
South West Africa ◽  
The Tropics ◽  
World Distribution ◽  
North Western

In further studies of grass distribution, maps are presented showing the world distribution of the Eragrosteae (sensu str.) and of the subfamily Eragrostoideae within which it is included. Both taxa show centres of high relative specific differentiation in inland Australia and in South West Africa, but in addition, the subfamily has centres of differentiation in the Sahara rekion, northern Mexico, and north-western India. The centres of differentiation are all in regions of hot, arid climate near the tropics of Cancer and Capricorn. The close relationship between climate and distribution is most apparent in the case of the subfamily Eragrostoideae, species of which are relatively abundant in the grass flora of all arid regions with high winter temperatures and summer or non-seasonal rainfall incidence. The distributions of most of the other tribes and subtribes which have been included in the Eragrostoideae show a similar relationship to climate. Some apparent exceptions to this are discussed, and it is shown that the geographical evidence supports conclusions from recent cytotaxonomic and anatomical studies that the taxa concerned should be removed from the subfamily. The very wide distribution of the subfamily and of its constituent taxa, as well as the close relationship between the distribution pattern and climate, suggests that the subfamily is a very old one. Geographical and taxonomic evidence indicates that it may have originated in tropical or subtropical Africa at least as early as the Oligocene.

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