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This study demonstrated the influence of downscaling using the regional climate model (RCM) driven by Era-Interim reanalysis (EIN) in simulating different aspects of the Indian summer monsoon (ISM). It is also examined, whether increasing the horizontal resolution of RCM will inevitably be capable of adding more information to ISM characteristics and its spatio-temporal variability. In this regard, two RCM (at 50 km: Reg50 and 25 km: Reg25) simulations were conducted for six years from 2000 to 2005 for the South Asia Coordinated Regional Downscaling Experiment (CORDEX) domain. The added value (AV) is found to be strongly dependent on region and considered metrics. A slight improvement towards increasing spatial resolution is observed in the simulation of the mean ISM characteristics, while considerable improvements are noticed for the frequency distribution of extremes. The notable improvement in the daily climatology of precipitation is observed over the region of northeast India (~ 35%) and the Hilly region (~ 32%) and the lowest improvement over north-central India (~ 8%). The reduction of anomalously strong northeasterly flow over the southeastern Arabian Sea and strengthening of the moisture leaden southeasterly wind flow from the Bay of Bengal in Reg25 compared to Reg50 is consistent with the reduction of dry bias over India in Reg25. The robust improvements are noticed for the heavy precipitation events (probability density function: PDF tails) and mean precipitation due to extreme precipitation events, particularly over the areas characterized by complex topographical features (e.g., the Western Ghats, Indo-Gangetic plains, and northeast India and Hilly regions) as well as over the areas having substantial bias (e.g., central India), indicating its strong sensitivity towards model resolution. The increasing latent heat flux in Reg25 contributes to increasing the moisture and hence rainfall over India. Both simulations apparently simulate many of the ISM characteristics better than the EIN, thereby emphasizing the usefulness of finer resolutions in the better simulation of the Indian monsoon, especially for heavy rainfall. However, the RegCM bias is comparable to or even greater in some places than the EIN bias. This suggests that high-resolution models are important for improving performance; however, it does not necessarily mean that they can have AV for every aspect and all places. Apart from this, the substantial difference in the AV over different regions or aspects highlights the importance of carefully selecting AV matrices for the different areas and characteristics being investigated. RegCM exhibits some systematic biases in precipitation despite substantial improvement due to misrepresentation of dynamical and thermodynamical processes, including northward and eastward propagating convective bands. [ABSTRACT FROM AUTHOR]

An effort is made to implement a regional earth system model (RESM); ROM, over CORDEX-South Asia (SA). The added value of RESM is assessed for mean precipitation, its variability (intraseasonal to interannual), extremes, and associated processes. In this regard, ROM's fields are compared with the respective fields of its standalone version (REMO), the models belonging coupled model intercomparison project (CMIP5 and CMIP6), and regional climate models of CORDEX-CORE simulations. RESM shows substantial improvement for most of the Indian monsoon's aspects; however, the magnitude of the value addition varies spatiotemporally and also with different aspects.. The improved representation of intraseasonal variability (active-break spell's duration and intensity) and Interannual variability attributed to improved mean seasonal precipitation. Additionally, correct representation of sea surface temperature, Indian Ocean Dipole, and its underlying dynamics also contribute to improving the mean precipitation. The notable improvement is seen especially over the south-eastern regions of the Bay of Bengal (BoB) and South-Central India, where increasing (decreasing) low-pressure systems over Central India (BoB) are noticed as a consequence of air-sea coupling, leading to enhanced (reduced) precipitation over Central India (BoB), reducing dry (wet) bias found in REMO and the other models. Despite substantial improvements, RESM has a systematic wet bias in the mean precipitation associated with a warm bias over the western coast of the Arabian Sea. An overestimation of very high extreme precipitation due to the enhanced contribution of low-pressure systems indicates the model's limitations, suggesting the need for further tuning of the RESM. [ABSTRACT FROM AUTHOR]

Introduction: Allelic frequency distribution of drug metabolizing enzyme genes among populations is important to identify risk groups for adverse drug reaction and to select representative populations for clinical trials. Although India emerged as an important hub for clinical trials, information about the pharmacogenetic diversity for this region is still lacking. Here, we investigated genetic diversity of cytochrome-P450-2C9 (CYP2C9) gene which metabolizes wide range of drugs and is highly expressed in the human liver. Methods: In total, 1278 individuals from 36 diverse Indian populations, 210 individuals from in-house data-repository and 489 other South Asian samples from the 1000 Genomes Project were selected. Variants observed in CYP2C9 gene were subjected to various statistical analyses. Results: High frequency of CYP2C9*3 (∼ 13%) and CYP2C9*3/*3 (∼ 1%) was observed among South Asians, compared to 21 populations living outside the Indian subcontinent. The allelic/genotypic frequency does not correlate with geographical location or linguistic affiliation, except populations speaking Tibeto-Burmans language, who have lower frequency of CYP2C9*3 and CYP2C9*3/*3. Since, South Asians practice strict endogamy, presence of unique mutation and high frequency of homozygous genotypes not surprising. CYP2C9*3 has been associated with therapeutic response.The effect of CYP2C9*3/*3 is more pronounced compared to heterozygous and wild type homozygous genotypes as evident in many in vitro studies. As South Asians have high frequency, it would be interesting to explore potential of CYP2C9*3 as a marker for personalized therapy. Our study revealed several rare functional variants, which form eight novel and rare haplotypes of CYP2C9 (CYP2C9*63–*70). Of which, CYP2C9*64, *65, *66, *68, *69 and *70 haplotypes are South Asian-specific. Conclusion: Overall, we find high genetic heterogeneity within South Asians and identified South Asian-specific putative functional CYP2C9 haplotypes. High frequency of CYP2C9*3 and CYP2C9*3/*3 was observed in South Asian populations. Taken together, current study greatly enriches the knowledge of naturally occurring CYP2C9 variants and its diversity in South Asia, which are relevant to further CYP2C9-related functional research and for personalized medicine. [ABSTRACT FROM AUTHOR]

Palaeoclimatic reconstructions from sediment cores of the Arabian Sea, Bay of Bengal, and other terrestrial ecosystems including lakes, peatlands and proglacial areas from the Indian subcontinent have been used to understand the past Indian Summer Monsoon (ISM) variability. The core monsoon zone (CMZ) of India is one of the most important regions to understand past ISM dynamics. Pollen based palaeoclimatic reconstructions in the CMZ of India suggest a progressive increase in the ISM during the Holocene. However, the results suggesting a weak ISM after the Younger Dryas (YD) cooling event are contrary to the observations made in other parts of the country. Besides this, the minor climatic fluctuations are difficult to find in most of the reconstructions. This may be attributed to poor sample resolution and chronological control. These limitations make it difficult to ascertain whether the response of vegetation to climatic change has been insignificant or whether this change is not reflected in the proxy (proxy response). As a consequence, we argue that pollen based palaeoclimatic reconstructions are one of the most widely used proxies and will be meaningful as backbone for climate models only if the reconstructions become more quantitative. [ABSTRACT FROM AUTHOR]

This study investigated the impact of the Arabian Sea (AS) warming in modulating the winter precipitation over the Indian subcontinent and associated dynamical response such as subtropical jet variability using regional climate model, RegCM4.7 of the International Centre for Theoretical Physics (ICTP). In this regard, a control run (Reg CTL) is forced by real sea surface temperature (SST), and two sensitivity experiments with uniformly increased SST over AS by 0.45 °C (Reg SST45) and 0.90 °C (Reg SST90) are performed. The results obtained from a control experiment (Reg CTL) are compared with corresponding values from RegSST45 and RegSST90 to assess the warming impact. The model (Reg CTL) realistically simulates the circulation features, precipitation, and temperature over the Indian subcontinents in the winter season (November–December-January-February; NDJF) during 2006–2015. It is found that AS warming increases the precipitation over most parts of India during winter. The precipitation response varies with the month (NDJF) and the magnitude of AS warming. In general, precipitation is found to intensify with increasing AS warming over northern India and adjoining south Asian nations like Afghanistan, Pakistan, and some parts of Burma and Nepal. The strengthening of STJ is observed due to AS warming (Reg SST45). The strengthening of the subtropical jet (STJ) persists with an intensification of AS warming (Reg SST90); however, the magnitude of strengthening is less than Reg SST45, which is consistent with the corresponding increase of precipitation over India. Cold wave duration is found to be significantly sensitive to the intensity of AS warming. It is noticed that the AS warming increases the cold wave duration over the northern part of India with major increases over the western Himalayan region. • RegCM shows resemblance to observation in simulating winter monsoon characteristics and associated mechanisms. • The Arabian Sea warming impact in modulating winter precipitation over the Indian subcontinent is investigated • The precipitation increases over most parts of India during winter that varies with months and levels of warming. • The strengthening of the subtropical jet (STJ) is consistent with the precipitation increase. [ABSTRACT FROM AUTHOR]

Abstract: Single-grain optically stimulated luminescence dating was applied to Late Quaternary sediments at two sites in the Middle Son Valley, Madhya Pradesh, India. Designated Bamburi 1 and Patpara, these sites contain Late Acheulean stone tool assemblages, which we associate with non-modern hominins. Age determinations of 140–120ka place the formation of these sites at around the Marine Oxygen Isotope Stage 6–5 transition, placing them among the youngest Acheulean sites in the world. We present here the geochronology and sedimentological setting of these sites, and consider potential implications of Late Pleistocene archaic habitation in north-central India for the initial dispersal of modern humans across South Asia. [Copyright &y& Elsevier]

This study analyses the impacts of climate change on water resources in the Banas River Basin, which is located in a semi-arid part of the state of Rajasthan in India. A bias-corrected ensemble mean of three CORDEX-SA driving GCM experiments (CNRM-CM5, CCSM4, and MPI-ESM-LR) was used with the Soil Water Assessment Tool (SWAT) to predict water yield and evapotranspiration for three future periods (2011–2040, 2041–2070, and 2071–2099) under two representative concentration pathway scenarios (RCP4.5 and RCP8.5), and the results were compared with the data of a historical period (1979–2008). The SUFI-2 method was used for the calibration and validation of the SWAT model. The model was calibrated for the period of five years (1982–1986) and validated for the next five years (1987–1991). The values of R2, NSE, bR2, PBIAS, and RSR were, respectively, 0.78, 0.77, 0.61, 47.4 and 0.48 during the calibration period, and 0.71, 0.65, 0.60, 72.1 and 0.59 during the validation period. Trend analysis was also performed for annual future predicted flows using the Sen Slope method. From the results, it can be predicted that precipitation, evapotranspiration, and water yield will increase in all the three future periods under both RCP4.5 and RCP8.5. Water availability in the future in the basin (zone wise) was identified using appropriate indicators. Per-capita water availability and meteorological variation were used to calculate future water availability and, considering these indicators, it can be concluded that zone 3 will better than the other zones. Zone 3 exhibits high values of per capita water availability and meteorological variation. This study will be useful in understanding the impacts of climate change on the water availability of the river basin and may help in overall water management in the present and the future. Unlabelled Image • SWAT model was applied to study the water security using Ensemble CORDEX-SA climatic model at the basin level • Calibration and validation of model were satisfactory, the R2 is 0.78 and 0.71 • Water security analysis on the basis of per capita water availability and meteorological variation in the future periods [ABSTRACT FROM AUTHOR]

For the first time for CORDEX-South Asia, a high-resolution regional earth system model (ROM) is adopted to assess the impact of horizontal resolution (0.22° and 0.11°) in simulating the Indian summer monsoon rainfall (ISMR) and the underlying spatiotemporal variability. ROM at both resolutions bears a close resemblance to observations in simulating the mean precipitation climatology compared to other regional climate models (RCMs) participated in CORDEX- South Asia. ROM shows substantial improvement relative to the ensemble mean of the RCMs included in CORDEX-South Asia. While comparing both simulations with observations, some systematic wet and dry bias over Central India (CI) and Northern Western Ghats is noticed. In general, the wet/dry bias over India is mainly associated with the overestimation/underestimation of the large-scale/convective component. Increasing horizontal resolution from 0.22° to 0.11° significantly adds value in simulating the JJAS mean precipitation by reducing the wet bias over western central India (WCI) and southern peninsular India and dry bias over eastern CI. The reduction in wet/dry bias is mainly associated with suppression/enhancement of the large scale/convective precipitation. This improvement in mean precipitation is partially due to the improved representation of the propagation of mesoscale systems such as boreal summer intraseasonal oscillation (eastward and northward). Despite the above improvements, the wet precipitation bias, particularly over WCI, persists. The weaker Findlater Jet associated with weaker land-ocean thermal contrast caused by the warm sea surface temperature (SST) bias over the western Arabian Sea (AS) suggests that AS moisture transport does not contribute to the wet bias over India. The wet bias is possibly associated with favourable atmospheric conditions (atmospheric instability). • A high-resolution regional earth system model namely ROM is implemented over CORDEX-South Asia. • The impact of horizontal resolution (0.22° and 0.11°) in simulating the summer monsoon characteristics is investigated. • The improved representation of the dynamical and thermodynamical processes yield better monsoon simulation. [ABSTRACT FROM AUTHOR]