Indian Region Research Articles

3D assimilation and radiative impact assessment of aerosol black carbon over the Indian region using aircraft, balloon, ground-based, and multi-satellite observations

Abstract. A three-dimensional (spatial and vertical) gridded data set of black carbon (BC) aerosols has been developed for the first time over the Indian mainland using data from a dense ground-based network, aircraft- and balloon-based measurements from multiple campaigns, and multi-satellite observations, following statistical assimilation techniques. The assimilated data reveal that the satellite products tend to underestimate (overestimate) the aerosol absorption at lower (higher) altitudes with possible climate implications. The regional maps of BC-induced atmospheric heating derived using this data set capture the elevated aerosol heating layers over the Indian region along with the spatial high over the Indo-Gangetic Plain. It is shown that, over most of the Indian region, the incorporation of realistic profiles of aerosol absorption/extinction coefficients and single scattering albedo into the radiative transfer calculations leads to enhanced high-altitude warming. This could strongly influence the upper-tropospheric and lower-stratospheric processes, including the vertical transport of BC to higher altitudes, and thus have larger implications for atmospheric stability than what would be predicted using satellite observations alone. This will have larger implications for atmospheric stability than what would be predicted using satellite observations alone and could strongly influence the upper-tropospheric and lower-stratospheric processes, including increased vertical transport of BC to higher altitudes. The 3D assimilated BC data set will be helpful in reducing the uncertainty in aerosol radiative effects in climate model simulations over the Indian region.

Model simulation of carbonaceous fine particulate matter using SAFAR emission inventory and comparison with EDGAR-HTAP simulations

In this study, the evaluation of carbonaceous fine particulate matter (C-PM) was conducted using the SAFAR-India regional model. Two emission inventories were utilized: the newly developed SAFAR inventory and the global EDGAR-HTAP inventory, both for the year 2018. The simulation aimed to capture the seasonal and spatial patterns of black carbon (BC) and organic carbon (OC) concentrations. To validate model results, surface meteorological parameters, and C-PM concentrations were compared with the MERRA reanalysis data for the Indian region. Model simulated surface C-PM concentration with SAFAR emission inventory is found to be slightly overestimated (1.10), whereas simulated results with EDGAR emission inventory is significantly underestimated as compared to MERRA data. Model-simulated meteorological parameters showed a better correlation with MERRA reanalysis. Simulated geographical patterns of seasonal mean C-PM with SAFAR emission inventory exhibit quite a better comparison with MERRA reanalysis as against EDGAR simulated results. However, some differences in the present results are visible, particularly over the IGP region, as compared to MERRA data, but they are mainly attributed to a significant difference in the special resolution of present results (much finer) as compared to coarser MERRA data. In the Indo-Gangetic Plain (IGP) region, the concentration of BCSF and OCSF (BC and OC with SAFAR emission, respectively) show the peak during the winter, followed by the post-monsoon season. Although the correlation coefficients of hourly time series of surface BCSF and OCSF concentrations with MERRA over India are high (0.92 and 0.88), the poor RMSE, is attributed mainly to different scales of resolution. The model simulated BC, and OC concentrations with SAFAR emission input capture the pattern of spatial distribution reasonably well. The present evolution of BC and OC will help to better quantify their impact on climate and atmospheric conditions over the Indian region.

Analysis of differential code biases for GPS receivers over the Indian region

Abstract The GPS Aided Geo Augmented Navigation (GAGAN) system provides the navigational services for single-frequency GNSS user via broadcasting the differential corrections with GEO stationary satellites. The significant differential correction contribution comes from ionospheric time delays and is necessary to be determined precisely. Dual-frequency GPS receivers measure the ionospheric time delays using GPS code and carrier phase measurements. The determination of absolute ionospheric Total Electron Content (TEC) requires the calibration of GPS satellites and receiver hardware biases due to different frequency-dependent signals (L1 and L2) due to environmental changes (Temperature and Humidity). In this paper, A receiver-based Differential Code Biases (DCB) algorithm is implemented to derive a joint estimation of TEC and RDCB parameters using the weighted Least Square (WLS) method. The daily averaged DCBs data for 26 GPS receivers are obtained for 3 years (2014–2016) from 26 GPS reeivers over Indian region. The receiver DCB algorithmis validated with the Fitted Receiver Biases (FRB) method. The correlation (R) between VTEC and RDCB is conducted to investigate the RDCB stability. The results would be useful for the accurate determination of ionospheric differential corrections to GAGAN users.

A long-term drought assessment over India using CMIP6 framework : present and future perspectives

Research on the characteristics and spread of droughts has progressed significantly for future climate scenarios. However, studies on drought mitigation in relation to climate change have been largely inadequate. This study focuses on the severity and frequency of drought events based on meteorological properties of drought under two climate change scenarios: Shared Socioeconomic Pathway (SSP2 4.5 and SSP5 8.5). We utilized the Sixth International Coupled Model Inter-comparison Project sixth phase (CMIP6) ensemble General Circulation Models (GCMs) to collect historical (1901-2014) and future (2025-2100) precipitation data. IMD gridded precipitation was used as a reference data for comparative studies. We constructed the Standardized Precipitation Index (SPI) under two different Socioeconomic Shared Pathways (SSPs) to analyze future drought scenarios in the Indian region. Our results show a gradual increase in SPI values for future years, indicating an increase in the severity of drought events in the Indian region. The increase is more pronounced under the SSP5 8.5 scenario, which assumes high greenhouse gas emissions and limited climate change mitigation efforts. Furthermore, our results suggest that major dry spells are likely to occur in the first half of the future period, particularly in the case of ACCESS-ESM, one of the GCMs used in our analysis. In contrast, the NOR-ESM-MM model indicates that dry spells are anticipated throughout the entire future period. Overall, our study provides valuable insights into the potential impacts of climate change on drought events in the Indian region.

Gender, Religion and Higher Education: Strategies of Muslim Women Students in India

Social scientists critically examine the role of higher education in women’s empowerment. In the Indian context, gender, religion, caste, class and region are crucial in determining access to education. The gender gap has been a significant obstacle in India’s pursuit of educational goals. The status of Muslim women’s education has been a contested policy from state and community vantage. Prominent scholarly writings argue that Muslim women were even more isolated from the social and cultural changes than their men were and even more invisible in the public arena of society. Their condition is more pathetic in educational and cultural realms. The primary objective of this paper is to empirically outline the negotiation and strategies employed by Muslim women students in negotiating with their families, religion, communities and careers. The study followed qualitative methodology to understand Muslim women’s educational choices, the rationale behind their educational decisions, and their agency in negotiating with their families and the career prospects of young Muslim women. The current paper argues that there is a remarkable growth in the history of women’s education in India, especially after the 90s, which could not change the social structure and social status of women in society in general and Muslim women in particular. Still, the gender differences remained stable in the educational practices, in the families, and even in the equity-minded educational committees. According to various government reports and studies, despite the improvement in the educational enrolment rate of Muslims, the representations of the Muslim community in general and Muslim women, in particular, are minimal in higher education. More than looking at the representation of Muslim women in education institutions, the current paper will analyse the challenges and experiences of Muslim women to reach the secondary and higher secondary levels of education.

The Cytotoxic and Anti-tumor Potential of Methanolic Extracts of Indian Marine Isolates in HCT116 Colorectal Cancer Cells.

The marine environment is a rich source of biodiversity, with several of its inhabitants producing unique and physiologically active substances. The use of marine bacterial-derived chemicals over traditional pharmaceuticals is gaining traction due to their larger variety of targets and modes of action. To circumvent the drawbacks of current therapy options, researchers have looked to marine microbes for novel and effective anti-cancer compounds. In this study, we examine one of India's least-examined coastal areas in search of novel bacterial sources of anti-cancer chemicals. Soil sediments from the Indian south coast region were collected and microbes were isolated using standard methods. The microorganisms were identified using 16s rRNA sequencing, and cytotoxic extracts were further examined using GC-MS. MTT, clonogenic, and spheroid tests assessed the extract's cytotoxicity and anti-tumor efficacy. Our results indicated that the bacterial isolates with potent cytotoxic activity were Bacillus drentensis and Bacillus haikouensis and had 10 and 12 potent anti-cancer and other bioactive compounds. The extracts had an IC50 of 30.08 and 109.4 μg/ml in the HCT116 cell line, respectively, and strongly inhibited colony formation. The cell cycle analysis indicated that the extract induced cell death as indicated by the subG0 peak. We also showed that these methanolic extracts induced toxicity in a 3D spheroid model indicating a strong anti-tumor activity. Furthermore, we performed molecular docking for the compounds present in the extracts to VEGFR and nucleolin and found that ergostane had favorable binding energy only to VEGFR. The results indicate that the ME of B. drentensis and B. haikouensis contains potent anti-cancer compounds to exhibit cytotoxic and anti-tumor activity in colorectal cancer cells.

Application Potential of Wastewater Fertigated Short Rotation Coppice Systems in a Selected Region (Aligarh, UP, India)

In many Indian regions, increased wastewater is both a threat to public health and the environment, but it also presents an opportunity as a source of water and nutrients. With less than one-third of India’s wastewater treated and an alarming water scarcity situation, efficient wastewater treatment and reuse schemes are needed to face impending water and fertiliser shortages. This study explores the application potential of wastewater fertigated Short Rotation Coppice systems (wfSRC) as a cost-efficient and promising solution for treating and reusing wastewater in a specific region (400 km2, 184 settlements) of Aligarh (UP), India. Based on real data from a local wfSRC pilot site using bamboo, willow, and poplar, we analysed the system’s treatment performance, nutrient recovery, carbon sequestration potential, land requirements, biomass production potential, and cost–benefit, under various scenarios. The results show that the pilot wfSRC system is efficiently treating 250 m3/day of domestic wastewater on 6864 m2 of land, and serving 2500 people. The land requirements for wfSRC systems vary depending on local conditions (e.g., climate, soil type, wastewater composition) and user demands (e.g., water reuse efficiency, type, and amount of biomass). The calculated areas ranged from 2.75 to 25.7 m2/PE, which equates to a required land area in the whole study region of between 108 and 1006 ha in 2036. This would produce up to 100 DM t/ha/year of valuable biomass. Early local stakeholder involvement and the monitoring of pollutants are recommended as priorities during the planning process for the large-scale implementation of wfSRC systems in India.

Effects of atmospheric aerosols on heat stress over South Asia

The recent trend in global mean temperature is expected to increase the frequency, duration, and intensity of heat waves and heat stress all around the world, especially over the Indian subcontinent. To investigate the plausible mechanisms and implications of meteorological feedback of aerosol forcing on heat stress over South Asia, simulations using a regional climate model (RegCM4) coupled with aerosols were carried out from 2015 to 2019. Generally, extreme heat days are observed mainly over the central and western Indo-Gangetic plains (IGPs) during May. The two heat-humidity indices, wet-bulb temperature (WBT) and heat index (HI), showed moderate effects due to aerosol forcing despite the high aerosol loading during the pre-monsoon. The inclusion of aerosols leads to surface cooling (a reduction in maximum surface temperature), with the highest impact over western India (WI) and the IGP. However, this surface cooling due to aerosols is compensated by an increase in near-surface relative humidity (RH), leading to an increase in WBT and HI. This compensating effect of RH on WBT and HI is greater in WI than that in eastern India. Regional heterogeneity in aerosol-induced changes in heat stress has a strong dependence on land-atmosphere interactions. This study clearly shows that aerosol-induced changes in RH play a decisive role in the assessment of heat stress, which answers the link between the prevalence of high heat stress conditions despite high aerosol loading (surface cooling) over the Indian region.

Detection and molecular characterization of Copamyntis obliquifasciella (Hampson, 1896) infesting medicinal plant, Cassia fistula L from India

Cassia fistula L. is a valuable medicinal plant utilized in many traditional medical systems, including Ayurveda and Oriental medicine system. Copamyntis obliquifasciella Hampson (Lepidoptera: Pyralidae) is a polyphagous insect pest, however the available literature of this pest on C. fistula is limited or rather scarce in India as well as world. Considering the economic importance of this medicinal plant, documentation of insects pests along with the bio-ecology and natural enemy fauna is important for formulating the integrated pest management program. The present study describes the incidence, damage and life cycle of C. obliquifasciella on C. fistula in India. The identity of the pest was confirmed through the examination of morphological characteristics of male and female genitalia, further confirmed through molecular analysis (GenBank no. MK559413). The phylogenetic analysis revealed that the Indian population of C. obliquifasciella shared a close relationship with the populations from Pakistan and China. The initial instar larvae of C. obliquifasciella is feed by nibbling and scraping the chlorophyll content of the leaves, and later they stitch two or three leaves together and fed in between those stitched leaves. The percent pest incidence varied between 20 and 100, and the foliar damage of 5.5–71% was recorded. The total life cycle of C. obliquifasciella was completed in 31.20 ± 2.14 (male) and 34.25 ± 2.36 (female) days. Two hymenopteran parasitoids, such as Phanerotoma sp. (Braconidae: Cheloninae) and Apanteles taragamae Viereck (Braconidae: Microgastrinae) were associated with C. obliquifasciella. To best of our knowledge, this is the first description of C. obliquifasciella and their associated natural enemies from the Indian region.

Pyramiding resistance genes for bacterial leaf blight (Xanthomonas oryzae pv. Oryzae) into the popular rice variety, Pratikshya through marker assisted backcrossing.

Bacterial leaf blight (BLB) is one of the major biotic stress in rice cultivation. Management techniques, such as the development of BLB-resistant cultivars, are required to lessen the severity of the disease attack and yield losses. Pratikshya was selected in the present investigation as the recipient parent, as it is one of the popular high-yielding rice varieties of Odisha, India, which is having excellent grain as well as cooking quality. However, Pratikshya is highly susceptible to BLB which is prevalent in Eastern Indian region. Three major BLB resistance genes xa5, xa13, and Xa21 from the donor source Swarna MAS (CR Dhan 800) were attempted to introduce into Pratikshya through a marker-assisted backcross breeding program. Those markers closely linked to the target genes were employed for foreground selection in the segregating generations till BC2F3. In each backcross generation, progenies containing all three targeted resistance genes and phenotypically more similar to the recipient parent, Pratikshya were selected and backcrossed. Screening of 1,598 plants of the BC2F2 population was conducted against BLB using Xoo inoculum and 35 resistant plants similar to Pratikshya were carried forward to the next generation. In the BC2F3 generation, 31 plants were found to possess all the three resistance genes. For background selection of plants carrying resistance genes 45 polymorphic SSR markers were employed. Evaluation of the pyramided lines at BC2F4 generation exhibited that, most pyramided lines were similar to Pratikshya in terms of morphological features and yield parameters, and some lines were superior to the recurrent parent in terms of morphological features and yield parameters. The three-gene pyramided lines showed a high level of resistance to BLB infection and are anticipated to offer a significant yield advantage over the recipient parent Pratikshya.The pyramided lines can further be used for multi-location trial, so as to be released as a variety or can be used as a potential donor for BLB resistance genes.

Analysis of Total Electron Content (TEC) Variations over Low-Latitude Indian Regions during a Low Sunspot Year of Solar Cycle 24

The Total Electron Content (TEC) measurements from two stations in the Indian sector, namely the equatorial station Bangalore (Geographic latitude 12°, 58' N, longitude 77°, 35' E) and the equatorial ionization anomaly (EIA) station Varanasi (Geographic latitude 25°, 19' N, longitude 82°, 59' E), are used to examine the variations of the TEC. In comparison to Varanasi, Bangalore has greater daytime TEC values. At the anomalous crest locations, significant daily changes in the TEC values are seen. Three distinct possibilities for the topside electron density present in the model (IRI-2001, IR01-Corr, and Ne-Quick) have been taken into consideration when comparing the observed GPS-TEC with the IRI-2016 model-derived TEC. While the TEC using the IRI01-Corr and IRI-2001 approach exhibits greater variances, the TEC obtained using the Ne-Quick options exhibits better agreement with GPS-TEC.

Identification of a shared, common haplotype segregating with an SGCB c.544 T > G mutation in Indian patients affected with sarcoglycanopathy

Sarcoglycanopathy is the most frequent form of autosomal recessive limb-girdle muscular dystrophies caused by mutations in SGCB gene encoding beta-sarcoglycan proteins. In this study, we describe a shared, common haplotype co-segregating in 14 sarcoglycanopathy cases from 13 unrelated families from south Indian region with the likely pathogenic homozygous mutation c.544 T > G (p.Thr182Pro) in SGCB. Haplotype was reconstructed based on 10 polymorphic markers surrounding the c.544 T > G mutation in the cases and related family members as well as 150 unrelated controls from Indian populations using PLINK1.9. We identified haplotype H1 = G, A, G, T, G, G, A, C, T, G, T at a significantly higher frequency in cases compared to related controls and unrelated control Indian population. Upon segregation analysis within the family pedigrees, H1 is observed to co-segregate with c.544 T > G in a homozygous state in all the pedigrees of cases except one indicating a probable event of founder effect. Furthermore, Identical-by-descent and inbreeding coefficient analysis revealed relatedness among 33 new pairs of seemingly unrelated individuals from sarcoglycanopathy cohort and a higher proportion of homozygous markers, thereby indicating common ancestry. Since all these patients are from the south Indian region, we suggest this region to be a primary target of mutation screening in patients diagnosed with sarcoglycanopathy.

India’s photovoltaic potential amidst air pollution and land constraints

India aims for ambitious solar energy goal to fulfill its climate commitment but there are limited studies on solar resource assessment considering both environmental and land availability constraints. The present work attempts to address this issue using satellite-derived air pollution, radiation, and land use data over the Indian region. Surface insolation over India has been decreasing at a rate of -0.29± 0.19 Wm-2 y-1 between 2001 and 2018. Solar resources over nearly 98%, 40%, and 39% of the Indian landmass are significantly impacted by aerosols, clouds, and both aerosols and clouds respectively. Only 29.3% of the Indian landmass is presently suitable for effective solar photovoltaic harnessing, but this is further declining by -0.21% annually, causing a presumptive loss of 50 GW solar potential, translating 75 TWh power generation. Lowering two decades of aerosol burden can make 8% additional landmass apt for photovoltaic use. Alleviating aerosol-induced dimming can fast-track India's solar energy expansion.

An overview of atmospheric aerosol and their effects on human health.

Epidemiologic investigations have previously been published in more than 200 papers, and several studies have examined the impacts of particle air pollution on health. The main conclusions now being made about the epidemiological evidence of particle pollution-induced health impacts are discussed in this article. Although there is no universal agreement, most reviewers conclude that particulate air pollution, particularly excellent combustion-cause contamination prevalent in many municipal and manufacturing environments, is a significant risk for cardiopulmonary sickness and mortality. Most epidemiological research has concentrated on the impacts of acute exposure, although the total public health implications of chronic acquaintance's outcome may be more extraordinarily significant. According to some reviewers, prolonged, repeated exposure raises the risk of cardiorespiratory death and chronic respiratory illness. A more general (but still universal) agreement is that short-term particle pollution exposure has been shown to aggravate pre-existing pulmonary and cardiovascular diseases and increase the number of community members who become sick, require medical treatment, or die. Several in-depth studies conducted in the global and Indian regions are addressed.

Long-term changes in rainfall epochs and intensity patterns of Indian summer monsoon in changing climate

The rainfall spell patterns of the Indian Summer Monsoon (ISM) and their respective intensities have been analyzed in light of changing climate by using climatology of gridded rainfall data during the period 1901–2022. The active and break days over the monsoon core zone are identified for peak monsoon months for each year based on the standard criteria. In general, maximum of four active spells are observed within the monsoon season (99% of the time) with occasional occurrences of additional spells. A significant change is observed from 1901 to 2022 in the contribution of each active spell to the respective cumulative ISM rainfall; but the sum of all the active spells rainfall contributions remained the same. The spell-1 rainfall contribution to the total ISM rainfall is decreasing (−0.4 ± 0.15 mm/decade); while it is increasing (0.22 ± 0.11 mm/decade) in spell-2. Also, it is found that the number of break days between the first and second active spells is declined by 11 days over 122 years along with the enhancement in the number of second active spell days. It is proposed that these may be partly due to the observed decline in the northward propagation speed of the monsoon and partly due to significant shift from positive to negative cloud radiative forcing over the Indian ocean region during the first-half (June–July) of the monsoon to the second-half (August–September) of the monsoon. In addition, the probability density distribution of active spell-4 is observed to be distinctly different from the rest of the active spells. In association, the monsoon trough axis is observed to be shifting southward along with the weakening of low level winds (at 850mb level) from beginning to the end of the active monsoon season. Concurrently, in-situ observations of drop size distributions of low, moderate and extreme rainfall events suggests that the controlling microphysical processes shift from size controlled to number controlled drop size distributions with extreme rainfall events being primarily number controlled. Thus, the significance of the present study may provide the better understanding of the role of duration active spells to the monsoon in changing climate.

Atmospheric–Oceanic Processes over the Pacific Involved in the Effects of the Indian Summer Monsoon on ENSO

Abstract This study investigates the physical mechanisms responsible for the impacts of the Indian summer monsoon (ISM) on the evolution of El Niño–Southern Oscillation (ENSO), with a focus on understanding the monsoon-induced Pacific air–sea interactive processes. An observational analysis displays that a weaker-than-normal ISM can strengthen an ongoing El Niño event and weaken a La Niña event, and conversely for a stronger-than-normal ISM. A 1000-yr output from the Community Earth System Model version 2 is capable of reproducing this observed feature and is therefore used to explore the responsible ocean–atmosphere interactive processes involved. Results show that a weak ISM can cause a cyclonic circulation over the western North Pacific via stimulating atmospheric cold Kelvin waves, and conversely for a strong ISM. The westerly (easterly) wind anomalies on the southern flank of the anomalous cyclone (anticyclone) generate eastward (westward) current anomalies in the mixed layer and thus induce anomalous warm (cold) zonal advection. Furthermore, the wind anomalies excite oceanic downwelling (upwelling) Kelvin waves, which deepen (shoal) the thermocline in the equatorial eastern Pacific and result in anomalous warm (cold) vertical advection. A quantitative mixed layer heat budget analysis demonstrates that the influence of the monsoon-induced Pacific wind anomalies on ENSO is mainly achieved by changing the zonal advective feedback and thermocline feedback. This result is confirmed by model sensitivity experiments in which additional monsoon heating or cooling anomalies are imposed over the Indian region during the developing summer of an ENSO event. Significance Statement While previous studies have reported that the Indian summer monsoon (ISM) could influence the evolution of El Niño–Southern Oscillation (ENSO), this study is aimed at understanding the physical mechanisms for the Pacific air–sea interactive processes induced by the monsoon and their impact on ENSO. It is found that a weak and strong ISM can respectively induce an anomalous cyclonic and anticyclonic circulation over the western North Pacific. The wind anomalies on the southern flank of the anomalous circulation mainly change the zonal advective feedback and the thermocline feedback to affect ENSO development. This study provides a detailed physical explanation of how the ISM influences ENSO evolution.

Heavy Mineral and Mineral Magnetic Tracers of Basaltic versus Cratonic Weathering as Indicators of Spatio-temporal Shifts in the Monsoonal Intensity over Central Indian Region

Abstract Indian summer monsoon holds its core over Central Indian Region (CIR) through Bay of Bengal and Arabian Sea branches. The majority of CIR is occupied by the Godavari Drainage Basin (GDB) which generates a large and episodic flux of sediments in the Bay of Bengal indicating a major shift in the monsoonal pattern over CIR. The large part of Deccan basalt province of GDB is present in the semi-arid watershed governed by the precipitation mostly from Arabian sea branch. Whereas the cratonic province is present in a high monsoonal zone governed by the precipitation from Bay of Bengal branch. Both these zones also represent Cratonic (non-basaltic) versus Basaltic sources converging at the Pranhita/Godavari confluence before their mixing onwards into delta and finally in the Bengal fan. Based on the heavy mineral and low temperature magnetic mineral characteristics of bed loads from the Godavari River before, at and after the confluence we attempt to characterise these two sources as a function of shift in monsoonal pattern over central India. The quantitative heavy mineral studies show dominance of stable minerals derived from the non-basaltic sources with a downstream trend for stable heavy minerals in a long profile to indicate stronger cratonic sources. The surface textures of garnet, epidote and hornblende indicate rapid transport and low residence time for the sediments derived from Precambrian granites, Proterozoic and Gondwana sediments presently defining the Core Monsoon Zone. The opaque grains represented by discrete ilmenite, magnetite and magnetite inclusions in aggregated quartz characteristic of the Deccan basaltic source show decreasing order downstream. The low temperature magnetic susceptibility for heavy minerals indicate Multi Domain and Ti-rich magnetite from Deccan basalts and magnetic inclusion in siliciclastic grains derived mostly from local sources. More detailed heavy mineral and geochemical analysis of the core sediments would help in documenting the temporal shifts in monsoonal intensity and its core regime over the Indian continent.

Total electron content forecasting with neural networks during intense geomagnetic storms of the solar maximum and moderate years of solar cycle 24 in the low latitude Indian region

Total electron content forecasting with neural networks during intense geomagnetic storms of the solar maximum and moderate years of solar cycle 24 in the low latitude Indian region

Changes in the mechanism of the South-Asian summer monsoon onset propagation induced by the pre-monsoon aerosol dust storm

A modeling effort is considered to understand the effect of dust aerosol storms in the Indian summer monsoon (ISM) onset propagation over the Indian subcontinent. The study found how the dust aerosol loading during the pre-monsoon period over the Indian subcontinent positively impacts the advancing ISM onset. The heavy loading of dust aerosol from middle east Asia to the northwest (NW) Indian region boosts the temperature gradient over the mid-troposphere. This sudden rise in the mid-tropospheric atmospheric temperature triggers the low-pressure belt over the monsoon trough. It amplifies the Elevated Heat Pump mechanism and loads enough dust for the dust storm over north India. The formation of the monsoon trough over the Indo-Gangetic Plain (IGP) pulls the moisture-loaded wind towards the Indian subcontinent and the IGP, followed by the onset of monsoon over Kerala within a week. Due to this storm, the intense heat gradient in the troposphere also induces the monsoon propagation and the monsoon advancement from Kerala to BoB within a short time. However, it makes up for the naturally delayed monsoon on time. Plain language summaryStudy shows how the pre-monsoon dust storm modulates the Indian summer monsoon (ISM) propagation over the Indian region. The onset of the monsoon was delayed in a particular year, and the pre-monsoon dust storm over northwest India changed the regular monsoon mechanism and generated an entirely different mechanism. The elevated heat pump theory applies that pushes the monsoon advancement faster than usual. A dust storm over north India causes a sudden rise in the mid-tropospheric temperature gradient and more rapid monsoon advancement than usual.

Preliminary performance analysis of BeiDou-2/GPS navigation systems over the low latitude region

Abstract On a regional or worldwide scale, satellite-based navigation systems can offer three-dimensional Position, Velocity, and Timing (PVT) services to an indefinite number of users. BeiDou-2 is China’s regional navigation satellite system that encompasses the Asia-Pacific region. BeiDou-2’s space section comprises GEO, MEO, and IGSO satellites, making it unique among the navigation systems. This research focuses on key aspects, including satellite visibility and signal strength, as a function of the elevation angle across the low latitude region (Indian region). In addition, the results were compared with those obtained using the GPS. The data is acquired from a GNSS receiver located at the Hyderabad station (latitude:17°24′28″, longitude:78°31′04″). The results show that BeiDou-2 satellites have better visibility than GPS satellites at all elevation angles. However, visibility is low at high elevations; therefore, multiple systems are required to obtain user information. As the elevation angle increases, the carrier-to-noise density ratio (C/No) also increases. Additionally, the standard deviation (STD) was calculated and compared to that of the GPS. Despite the average signal strength of GPS satellites remaining high throughout the elevation range, the STD of BeiDou-2 satellites was found to be low. These results indicate that further work is needed to improve the interoperability of multiple navigation systems and to provide more accurate location information to Indian users.