Northern Indian Region Research Articles

Enamel Hypomineralization: Prevalence, Defect Characteristics in Primary Dentition in a Northern Indian Region.

No data is available on hypomineralization in the full complement of primary dentition. To report on the prevalence and clinical presentation of enamel hypomineralization (EH) in the primary dentition. A cross-sectional observational study with a random sample of 948, 4-6-year-old schoolchildren of Gautam Buddh Nagar, Uttar Pradesh, India, was conducted after approval from the Institutional Ethics Committee. European Academy of Paediatric Dentistry (EAPD) (2003) criteria were employed to score EH in all primary teeth. A single experienced examiner conducted an entire clinical examination of the study population. Data were expressed as the prevalence, type, extent, and distribution. Further analyses were conducted to compare the prevalence and distribution of different types of lesions in affected subjects using student t-tests and analysis of variance (ANOVA). An overall prevalence of 7.51% (71/948) was reported. A total of 2.75 ± 1.735 teeth/subject were reported to be affected. The most common lesion was creamy white opacity (p = 0.002), while posteruptive breakdown (PEB) was observed in 40.85% (29/71) of affected subjects. The prevalence of EH in primary dentition was 7.51%. Further studies mapping the prevalence as well as possible links with molar incisor hypomineralization (MIH) in other geographical locations of the world are required. Mittal N, Gupta N, Goyal A. Enamel Hypomineralization: Prevalence, Defect Characteristics in Primary Dentition in a Northern Indian Region. Int J Clin Pediatr Dent 2024;17(S-1):S67-S72.

Distribution of ozone, carbon monoxide and oxides of nitrogen over an urban location in the foothills of the North-Western Himalayas

Increasing anthropogenic activities and biomass burning events over the Northern Indian region severely affect the pristine environment of North-Western Himalayas. To investigate their influence in this data sparse region, continuous monitoring of O3, CO and NOx are made during January 2018 to December 2019 over Dehradun, an urban location in the foothills of North-western Himalayas. Ozone shows daytime broad peak and CO and NOx show two peaks during morning and evening hours. The maximum daytime ozone is observed during spring with 58.2 ± 2.0 ppbv (56.2 ± 2.7 ppbv) during 2018 (2019). CO and NOx show maximum value during winter and minimum during summer-monsoon. Their concentrations are found to be influenced from stubble burning and forest fire emissions during late spring. WRF-Chem simulations are made with and without biomass burning emissions to quantify the contribution of these emissions on the variability of these gases over Dehradun. Sensitivity simulations reveal that biomass burning over northern Indian region contributed 43 ppbv, 79 ppbv and 1.2 ppbv increase in O3, CO and NOx mixing ratios over Dehradun. In addition, dust storm event in June 2018 contributed for lower ozone levels in 2018 (16.1 ± 9.3 ppbv) and stratosphere troposphere exchange process enhanced surface ozone in June 2019 (53.6 ± 22.3 ppbv).

GWAS for Early-Establishment QTLs and Their Linkage to Major Phenology-Affecting Genes (Vrn, Ppd, and Eps) in Bread Wheat.

Farmers in northern and central Indian regions prefer to plant wheat early in the season to take advantage of the remaining soil moisture. By planting crops before the start of the season, it is possible to extend the time frame for spring wheat. The early-wheat-establishment experiment began in the 2017 growing season at the Borlaug Institute for South Asia (BISA) in Ludhiana, India, and, after three years of intensive study, numerous agronomic, physiological, and yield data points were gathered. This study aimed to identify wheat lines suitable for early establishment through an analysis of the agro-morphological traits and the genetic mapping of associated genes or quantitative trait loci (QTLs). Advancing the planting schedule by two-three weeks proved to be advantageous in terms of providing a longer duration for crop growth and reducing the need for irrigation. This is attributed to the presence of residual soil moisture resulting from the monsoon season. Early sowing facilitated the selection of genotypes able to withstand early elevated temperatures and a prolonged phenological period. The ideotype, which includes increased photo-growing degree days for booting and heading, as well as a longer grain-filling period, is better suited to early planting than timely planting. Senescence was delayed in combination with a slower rate of canopy temperature rise, which was an excellent trait for early-adapted ideotypes. Thus, a novel approach to wheat breeding would include a screening of genotypes for early planting and an ideotype design with consistent and appropriate features. A genome-wide association study (GWAS) revealed multiple QTLs linked to early adaptation in terms of the yield and its contributing traits. Among them, 44 novel QTLs were also found along with known loci. Furthermore, the study discovered that the phenology regulatory genes, such as Vrn and Ppd, are in the same genomic region, thereby contributing to early adaptation.

Predicting the potential habitat suitability and distribution of “Weed-Onion” (Asphodelus tenuifolius Cavan.) in India under predicted climate change scenarios

Recent shifts in the spectrum of weeds documented throughout the globe in various agroecosystems were purportedly associated with climate change. Consequently, it called for a more thorough investigation of weed vulnerabilities and management in the changing climate scenarios. In the present investigation, we compile geographic occurrence data of an agricultural weed Asphodelus tenuifolius Cavan. using ecospat R package and BIOMOD ensemble forecasting to analyze the existing distribution and anticipate its possible distribution in the future under future climate change scenarios. Nine different algorithms were used and implemented in biomod2 package for modelling the current potential habitat distribution of the selected species across the study region and climatic data was downloaded from WorldClim database. Ensemble modeling showed high habitat suitability of the majority of central, northern, and western Indian regions under current climatic conditions. In addition, by gaining suitable habitats in the future the target species will undergo significant increase in range change. The potential range of habitat suitability for A. tenuifolius is likely to increase from 138.73% to 190.29% in terms of Committee Averaging and 721.42%–1508% in terms of Weighted Mean under Representative Concentration Pathways (RCP 4.5 and RCP 8.5). This ensemble modelling technique will help us to locate the places where its potential range could expand while simultaneously analysing the spatial distributions of field weeds, which may be important for the creation of cutting-edge weed control methods.

Significant Inverse Influence of Tropical Indian Ocean SST on SIF of Indian Vegetation during the Summer Monsoon Onset Phase

Sea surface temperature (SST) substantially influences the land climate conditions through the co-variability of multiple climate variables, which in turn affect the structural and functional characteristics of terrestrial vegetation. Our study explored the varying responses of vegetation photosynthesis in India to the SST variations in the tropical Indian Ocean during the summer monsoon. To characterise the terrestrial photosynthetic activity, we used solar-induced chlorophyll fluorescence (SIF). Our results demonstrated a significant negative SST-SIF relationship during the onset phase of the summer monsoon: the SIF anomalies in the northern and central Indian regions decrease when strong warm SST anomalies persist in the tropical Indian Ocean. Further, SIF anomalies increase with cold anomalies of SST. However, the negative SST anomalies in the tropical Indian Ocean are less impactful on SIF anomalies relative to the positive SST anomalies. The observed statistically significant SST–SIF link is feasible through atmospheric teleconnections. During monsoon onset, positive SST anomalies in the tropical Indian Ocean favour weakened monsoon flow, decreasing moisture transport from the ocean to the Indian mainland. The resultant water deficiency, along with the high air temperature, created a stress condition and reduced the photosynthetic rate, thus demonstrating negative SIF anomalies across India. Conversely, negative SST anomalies strengthened monsoon winds in the onset period and increased moisture availability across India. Negative air temperature anomalies also dampen water stress conditions and increased photosynthetic activity, resulting in positive SIF anomalies. The identified SST-SIF relationship would be beneficial to generate a simple framework that aids in the detection of the probable impact on vegetation growth across India associated with the rapidly varying climate conditions in the Indian Ocean.

Determining the Role of Employee Engagement in Nurse Retention along with the Mediation of Organizational Culture.

In today's unpredictable environment, the rapid emergence of the COVID-19 pandemic has shaken the world and its healthcare infrastructure immensely. As nurses are the building blocks of the healthcare personnel labor market, organizations should develop tactics that aid in their retention. With a solid theoretical foundation in self-determination theory, this study aims to understand the role of employee engagement in keeping nurses in 51 hospitals in the Northern Indian region, along with the mediation of organizational culture through smart PLS. In a complementary mediation relationship with organizational culture, nurse retention is positively correlated with employee engagement.

Family Social Capital and Life Satisfaction Among Working Women: Mediating Role of Work–Life Balance and Psychological Stress

A few studies have examined the factors that contribute to women's life satisfaction in the workplace. Some researchers have taken a gendered approach to this problem, arguing that stress and work–life balance has an effect on women's life satisfaction. This paper makes an important effort to investigate the link between family social capital (FSC) and life satisfaction among working women through the mediating influences of stress and work–life balance. Non-probability sampling was used to contact working women in the Northern Indian Region. The regression analysis showed that all the research hypotheses are supported. This work has made significant implications for scholars and practitioners. Unlike previous studies, this work has measured FSC as a multi-dimensional construct (family support, family interactions, family cohesion, and lack of family conflict). The results obtained are reliable and valid. This work can help academicians and practitioners to get a unique insight into the domain of FSC and life satisfaction.

Spatiotemporal Analysis of Future Trends in Terrestrial Water Storage Anomalies at Different Climatic Zones of India Using GRACE/GRACE-FO

This work is a climatological evaluation of terrestrial water storage anomalies (TWSAs), which act as driving forces for sustainable development, in one of the most populous countries of the world. The objective of this work is to evaluate RL06 mascon data from the GRACE and GRACE-FO satellite missions over India to explore seasonal and interannual changes in terrestrial water storage, encompassing an area of ~3.29 million km2 with 285 grid points, from 2002 through to 2020. Several statistical tests are performed to check the homogeneity (i.e., Pettitt’s test, the BRT, the SNHT, and the VNRT). Most of the homogeneous data are found in winter, pre-monsoon, and post-monsoon, approximately above 42% to 47%, and the least are found in monsoons and annual with only 33%, at a 95% significance level. According to Pettitt’s test, the majority of the breakpoints are present in 2014 for winter, 2012 for pre-monsoon, 2011 for monsoons and post-monsoon, and 2008 as well as 2011 for annual. Furthermore, to detect trends and magnitudes we employed the nonparametric MK test, the MMK test, Sen’s slope estimator, and the parametric SLR test. According to the MK and MMK tests, the most significant negative and positive trends indicate the chances of droughts and floods, respectively. The Indo–Gangetic region shows the highest declination. According to Sen’s slope and the SLR test, the most declining magnitude is found in Delhi, Panjab, Uttrakhand, the northern part of Rajasthan, and Uttar Pradesh. Based on our findings, the average declining rate of yearly terrestrial water storage data from the MK, MMK, and SLR tests is −0.0075 m (−0.75 cm/year) from 2002 to 2020. Koppen–Geiger climate zones are also used to depict the seasonal and interannual descriptive statistics of TWSA trends. Interestingly, the annual means of arid desert cold (−0.1788 cm/year) and tropical savanna (−0.1936 cm/year) have the smallest declining trends when compared to other climatic zones. Northern Indian regions’ temperate dry winter, hot/warm summer, and dry arid steppe hot regions show the maximum declining future trend. This study could be useful in planning and managing water resources, agriculture, and the long-term growth of the country by using an intelligent water delivery system.

Development of an empirical model for weighted mean temperature over North Indian region

Weighted mean temperature ( T m ) is an important parameter in the process of GPS precipitable water vapour (PWV) estimation. GPS PWV is obtained by multiplying a proportionality constant in zenith wet delay (ZWD). This proportionality constant depends on parameter T m . The parameter T m depends on surface temperature which varies from one place to another. When this variation is large, a more specific T m is required for a region for accurate PWV estimation. The topography of the northern Indian region is quite complex and the Himalayan mountains play a vital role in several atmospheric processes in this region. Thus a regional T m model is required for this region which should be developed with observational input over the foothills of northwestern Himalayas. In the present study, a regional weighted mean temperature model is developed over this region using five years of radiosonde observations from 2016 to 2020 over five stations New Delhi, Patiala, Dehradun, Jammu, and Srinagar. Site-specific models are also developed over these locations. Their accuracies are assessed with respect to existing site-specific, regional and global models and radiosonde observations. The results show that differences between developed regional model and existing regional and global linear models are less than 3 °K. The developed regional and site specific models have the T m differences of the order of 2 °K to 3 °K which is less than the difference between other models and radiosonde observations. Site-specific models provide slightly better accuracies (less than 1°K) when compared with the developed regional model. PWV is estimated using both the models and an average difference of less than 1 mm is found when compared with radiosonde observations. The developed regional model has better PWV accuracy than any other existing model in this region. Hence, both site-specific and regional models developed in this study can be used for further PWV estimation in the north Indian region.

Politics of Development in Bundelkhand Region of Northern India: Analysing Role of (Un)Civil Society

This study is an attempt to understand how development politics followed by the civil society organisations (CSOs) (with special reference to non-governmental organisations (NGOs) in India can be analysed in view of the social character of such organisations. The findings of this study are based on field work conducted in the northern Indian region of Bundelkhand. Bundelkhand is an economically underdeveloped, poverty ridden and draught-prone region located in the northern states of Uttar Pradesh (UP) and Madhya Pradesh (MP). The region suffers from deep-rooted social hierarchies and discrimination based on caste. Prevalence of such conditions of underdevelopment has also resulted in the emergence of vibrant CSOs in the region. However, the developmental agenda pursued by these organisations is largely confined to the questions of economic development including poverty alleviation, distribution of benefits of various state policies or raising concerns of depletion of natural resources especially of water scarcity. Larger structural questions of social justice, inclusion or participation of socially marginalised groups, especially of the scheduled castes (SC) and scheduled tribes (ST), have not received adequate attention in the agenda of most of these organisations. This study attempts to argue that what can explain this non-political nature of developmental agenda pursued by these CSOs is the social character of their leadership. A major reason behind the question of representation of social marginalised groups not being the core agenda of development is the continued dominance of social and economically dominant castes in managing these organisations. Though these groups do raise concerns of social equality and justice, it does not form the core agenda of development of the region. The state machinery or international aid agencies continue to work with the dominant sections as the agenda setters, while the representatives of marginalised communities continue to function at the margins of developmental agenda for the region.

Increasing Wind Speeds Fuel the Wider Spreading of Pollution Caused by Fires over the IGP Region during the Indian Post-Monsoon Season

Every year, forest fires and harvest harnessing produce atmospheric pollution in October and November over the Indo-Gangetic Plain (IGP). The fire count data (MODIS) shows a decreasing/increasing trend of fire counts in all confidence ranges in October/November over Northern India. There is a widespread increase in fires with a confidence level above 60 to 80% over the whole Northern Indian region. The Aerosol Optical Index (AOD) also shows an increase with values > 0.7 over the northwestern and IGP regions. There have been some startling results over the lower IGP belt, where there has been increasing trend in AOD during October ~56% and during November, the increase was by a whopping ~116%. However, in November, a slight turning of the winds towards central India might be transporting the AOD towards the central Indian region. Hence, during November, it is inferred that due to the low wind speed over the lower IGP belt and increased fires, the AODs in the polluted air tend to hover for a long time. During recent years from 2010, the winds have become stronger, indicating more transport of AOD is occurring over the lower IGP belt as compared to previous years till 2009, especially in October.

Estimation of surface temperature lapse rate over the Uttarakhand region using 107 station data and MODIS-LST data

An Altitudinal temperature lapse rate (TLR) is essential in understanding the local and regional climate over a mountainous region. This study estimated TLR for the Uttarakhand State in the Northern Indian region using MODIS-LST and the observed air temperature data extracted from the 107 Automatic Weather Stations. The objective of this study is to estimate the TLR: first directly from MODIS-LST and second from the observed station. The result of our analysis shows that MODIS-LST estimated TLR during day-time (−0.54 °C/100 m) is noticeably less accurate than the night-time (−0.59 °C/100 m) and; steeper at night in summer months and shallower during day in winter months. The spatial and temporal changes of TLR of 107 stations varies significantly with the steepest summer (−1.1 °C/100 m) and shallowest winter (−0.12 °C/100 m). Further, for the validation of performance, the MODIS-LST estimated TLR were found out to be highly correlated with the observed air temperature.

Sub-Surface Ocean Structure from Satellite Surface Observations in the North Indian Ocean

In this study interior plus Surface Quasi-Geostrophic (isQG) methodology is used to reconstruct subsurface density anomaly using sea surface temperature (SST), sea surface salinity (SSS) and sea surface height (SSH). The study is carried out in the Arabian Sea and Bay of Bengal of the Northern Indian ocean region. isQG is first tested for identical twin experiments, where the surface data and the stability profile (N2) were taken from a numerical ocean model. The root mean square error (RMSE) between isQG and model density anomalies lie within the error bars of model density anomaly in most of the levels. The impact of expected errors in synthetic observations of SST and SSS on isQG retrieved density anomalies was studied and it is found that error in SSS results in greater RMSE in isQG density anomaly profile in the Arabian sea than in the Bay of Bengal. isQG method is then applied to the satellite observations of SST, SSS and SSH and retrieved density profiles are then compared with model outputs and in-situ observations from RAMA buoy for the year 2019. The comparison indicates seasonal dependency and effect of N2 on the performance of isQG method.

<i>Terminalia chebula</i> (Harar) Characterization by using Morphological Descriptors in Himalayan Region

Terminalia chebula Retz. plays a crucial role in foodstuff, medicine, industry, and environmental protection. The skill of recognizing the variants of the species is very important in some applications, including conservation, strain types identification and performance of strains under different agro-ecological situation. However, it is a difficult task to identify plant species because it requires specialized knowledge. Developing morphological classification system for different genotypes and variants is necessary and valuable since it can help specialists as well as the public to identify and avoid cheating. It is a medicinal tree species which is highly valued in Indian system of medicine viz Ayurveda, Yunani, Sidha etc. Terminalia chebula trees are naturally distributed in the Sub Himalayan tract up to 1400 m above mean sea level in subtropical region, although planted trees can be seen in throughout the Northern Indian region. Research has been conducted to survey, locate the variations, identify the productive strains and also identify the ecological distribution of T. chebula in different agro-ecological regions of Himalayan region. The results indicated a high diversity in fruit and leaf shapes. Nine shapes of fruits were observed in the studied locations (Oblong “Matka type”, Oblong dark colour with short neck, Pyriform, Pyriform type fruit with Medium neck, Narrowly obovate without neck, Clavate with prominent neck, Oval, Ellipsoid and light coloured and Narrowly obovate medium in size with acute tip. Analysis showed that there were significant differences in leaf morphmetric characters, too. Nine shapes of leaves were observed in the region viz. Cuspidate, Elliptic, Aristate, Obtuse, Lanceolate, Ovate, Oblique, Ovoid and Oblong.

Sedimentation Pattern and its Controlling Factors in Indian Lakes

Sedimentation in lakes occurs from the time of its formation and continues till the final deposition. The rate of sedimentation varies depending upon climate, geology, soil cover and relief. In the present study, an attempt has been made to investigate the distribution and variation of sedimentation rate in Indian lakes. For this purpose, Indian lakes are classified into three zones viz., North Indian lakes (NIL), Central Indian lakes (CIL), South Indian lakes (SIL) and 27 sampling points distributed throughout India has been considered among all three zones. Correlation of rate of sedimentation data with catchment area, surface area and lithology is done in order to understand the controlling factors, rainfall and temperature data are also taken into consideration to know the effect on the sedimentation rate. In all three zones, the highest precipitation observed 2488, 1800 and 4000 mm/yr in the Nainital lake, Chilika lake and Pookot lake, respectively and temperature fluctuations in the northern region of India is higher than the central and southern region. The results showed that the NIL have relatively higher sedimentation rate compared to the CIL and SIL due to slopy terrain, higher precipitation, temperature and lithological inconsistency in northern Indian region whereas all these factors are less effective in other two zones with a minor contribution from other independent factors. NIL have ~0.634-0.804 cm/yr and ~0.636-1.117 cm/yr more sedimentation rate than CIL and SIL, respectively.

Comprehensive review of current trends in adenocarcinoma of gall bladder in northern Indian region: An imperative clinico-histological approach

We are aware that epidemiological studies have established significant geographical and ethnic differences and this disproportionality is quite high in Southeast Asia, but the numbers are few in the America and other parts of world. Age, female gender, congenital biliary tract abnormalities and genetic predisposition represent imperative irreversible risk factors. Environment factors too have been implicated in causing gallbladder carcinoma. Other causes of gall bladder carcinoma include bile duct cholelithiasis, chronic inflammatory conditions and parasite infestation. These occurrences are associated with high mortality rates. Countries with highest gallstone prevalence usually suffer with greatest gallbladder cancer mortality. Indistinct and unclear clinical signs frequently prolong the gallbladder cancer diagnosis and lead to its eventual development and poor prognosis. Therefore, surgery seems to be viable treatment option which is practiced all around the globe since decades. Some patients are lucky to have gallbladder cancer treated incidentally when cholecystectomy is performed for cholelithiasis. This review is an attempt to genuinely explore the current trends in adenocarcinoma of gall bladder in Northern Indian region by clinico-histological approach.

Boreal Spring El Niño Convective State and Its Impact on Monsoon Onset

AbstractA lesser known relationship between boreal spring El Niño state and the Indian summer monsoon (ISM) is explored, considering the differences in the evolution of sea surface temperature and convection over the Pacific. Rossby wave tracing analysis reveals that the boreal spring El Niño convective state permits two distinct eastward waveguides from the central Pacific to the ISM domain. The first waveguide reaches the northern Indian region roughly along the African‐Asian jet, and the second waveguide crosses over to the Southern Hemisphere over the eastern Pacific and extends up to the south Indian Ocean region. The net result is an altered free tropospheric temperature distribution over the ISM domain in the month of May leading to a delayed monsoon onset. The existence of the two waveguides and the modulation of monsoon onset makes the boreal spring El Niño state an important component to be accounted for in ISM prediction.

Ocular biometric analysis of cataract surgery candidates, referred from community outreach camps, organized at rural areas of central India

Background: Aim of this study was to analyse the ocular biometric parameters and their associations in a population of cataract surgery candidates.Methods: Ocular biometry records were retrospectively analyzed for 84634 patients with cataracts (84634 eyes) who were treated at Northern Indian region. Ocular biometry characteristics such as Axial length (AL), the Keratometry readings (K1 and K2), and Posterior chamber intraocular lens (PCIOL) power of patients were assessed to find mean, standard deviation, minimum value and maximum value. Statistical analysis was done in Statistical package for social sciences (SPSS) 22.0.Results: Age ranged from 1.0 years to 111 years (mean 63.9±9.24). Males were 43421 (51.3%) and females were 41213 (48.7%). Mean AL was 23.36±3.99 mm. Mean K1 was 44.79± 2.11 D. Mean K2 was 45.05±2.25 D and the average K was 44.92±2.01 D. Significant differences were observed in all the parameters when the findings for females and males were compared.Conclusions: The present study presents normative biometric parameters and their relationships in a rural Indian population. These results may be relevant not only in the evaluation of the refractive error but also in the Intraocular lens (IOL) calculation for cataract surgery. The greatest predictor of the ocular biometrics was age and gender. This would serve as initial normative data for the biometry values in the Indian adults going through cataract surgery because such facts are lacking in Indian population. the rural population.

Comparison of the Performance of Hybrid ETKF-3DVAR and 3DVAR Data Assimilation Systems on Short-Range Forecasts during Indian Summer Monsoon Season in a Limited-Area Model

The impact of deploying a flow-dependent ensemble error covariance in Weather Research and Forecasting (WRF) three-dimensional variational (3DVAR) data assimilation (DA) system is examined for short-range rainfall forecasts during an Indian summer monsoon season. The flow-dependent background error covariance (BEC) is generated using a 50-member ensemble, which is further updated using the ensemble transform Kalman filter (ETKF). Assimilation is performed using a Hybrid variational-ensemble (“Hybrid”) and traditional 3DVAR DA system during the 4 weeks of July 2013. The forecasted wind, temperature, and rainfall from the assimilation experiments are verified against corresponding observations. The results indicate that the flow-dependent ensemble background error covariance in 3DVAR has systematically improved the forecasted wind and temperature when compared to the traditional 3DVAR. Similarly, rainfall forecast skill is superior in the Hybrid experiments relative to that of 3DVAR. Convection-permitting resolution rainfall forecast is validated against 746 telemetric rain gauge observations over the state of Karnataka. The Hybrid experiments show higher quantitative precipitation forecast skill than 3DVAR, particularly towards the later stages of data assimilation cycling. Spatially, the 3DVAR experiment shows a dry bias over the upper peninsular regions and a slight wet bias over the central and the northern Indian regions, while the magnitude of such wet and dry biases is smaller in forecasts from Hybrid analysis. Additionally, the westerly wind over the peninsular Indian landmass analyzed by 3DVAR is considerably weaker than that analyzed by the Hybrid experiments. This is proposed as a possible reason for the reduced dry bias in rainfall forecasts over the Indian landmass in Hybrid versus 3DVAR experiments.

A new Western Disturbance Index for the Indian winter monsoon

The Himalayas are storehouse of freshwater, which is of utmost importance for agriculture and power generation for billions of people in India. Winter (December, January and February: DJF) precipitation associated with Western Disturbances (WDs) influences Himalayan climate, glaciers, snow-water storage, etc. One-third of annual precipitation over northern Indian region is received during winter. Winter WDs are synoptic-scale systems embedded the subtropical westerly jet (SWJ). Their orographic interaction with the Himalayas intensifies precipitation over Pakistan and northern India. Precipitation due to WDs and associated dynamics are termed as Indian winter monsoon (IWM). The present study focuses on the WDs climatology using National Center for Environmental Prediction/National Center for Atmospheric Research, US (NCEP/NCAR) reanalysis data. The period of study spans over 29 years (1986–2016) during which ~500 WDs were observed as per India Meteorological Department (IMD) daily weather report. Precipitation, vertical distribution of wind and geopotential height during the passage of these WDs are analyzed. Importantly, a new index, Western Disturbance Index (WDI), for measuring strength of IWM is proposed by using difference of geopotential height at 200 and 850 hPa levels. The index is able to capture changes in 500 hPa wind, air temperature and mean sea level pressure during the passage of WDs.