Northwestern Part Of India Research Articles

Short-term perturbation in aerosol characteristics over Northwestern India: A case study during Diwali festival

The present study examines the effect of Diwali festival (17–21 October 2017; 19th October was the Diwali day) on aerosol characteristics over Patiala, northwestern part of India. Diwali being one of the major festivals of India that falls between mid-October and mid-November is celebrated with full enthusiasm by burning crackers, fireworks, etc. During this period, the study site also is engulfed with high aerosol loading because of extensive paddy residue burning emission. During Diwali event, a particulate matter (PM10) concentration varies from 132 to 155 μg m−3, while a mass concentration of black carbon aerosols varies from 6 to 9 μg m−3 with the maximum concentration on post-Diwali day. Aerosol optical depth (AOD500) was maximum (0.852) on post-Diwali day indicating the additional loading of submicron particles due to burning of crackers and fireworks. The magnitude of single scattering albedo (SSA500) decreases to a minimum value around 0.864 showing abundance of absorbing aerosols on Diwali affected days (19th and 20th October). A sudden jump of +12.9 W m−2 in atmospheric radiative forcing resulting in a heating rate of up to 1.4 K day−1 on next day of Diwali shows the warming state of the lower and middle atmosphere.

Feeding trails of Dugong Dugong dugon (Müller, 1776) (Mammalia: Sirenia: Dugongidae) in the Gulf of Kachchh, western coast of India

Dugong Dugong dugon (Müller, 1776) is the only herbivorous marine mammal distributed along the tropical and subtropical oceans of the Indo-Pacific regions. The record of the species in India is mainly from the east coast including Andaman and Gulf of Mannar. In this note the authors have recorded feeding trails of Dugong on the Halodule uninervis meadow in the Gulf of Kachchh, i.e., northwestern part of India. Most of the records of this species from this area are stranding records. This is the second record of the trail from this region.

Effect of axial angulation of sacral vestibule s1 on morphometric analysis of sacral vestibule using plain computed tomography in north west Indian population

Background: The present study was aimed to study and develop in-depth understanding of the effect of the axial angulation of sacral vestibule S1 on morphometry of sacral vestibule in North-West Indian population presenting to our institution, which will go a long way in planning to treat the posterior pelvic injuries with percutaneous screws, thereby reducing the morbidity associated with open fixation. Methods: This study was conducted in the Department of Orthopaedics and Radiodiagnosis at Dr Rajendra Prasad Govt. Medical College, Kangra at Tanda over a period of one year. All the patients of the age >18 years and above submitting for either abdominal, lower spinal or non-orthopaedic pathology of pelvic region, presenting for computed tomography to the Department of Radiodiagnosis were included in the study.There was significant difference in axial angulation of S1 (P=0.000) and S2 (P=0.045) between males and females. Results: The axial angulation of S1 ranged from 2° to 23.0° with a mean value of 11.01°±3.74°. There was a significant difference in coronal angulation of S1 between age-groups 18-30 and 51-60 years (10.43±3.10 vs. 11.26±3.74; P=0.023).There was a weak relation between axial angulation of S1 and age-groups 18-30 years (r=0.195; P=0.013), 31-40 years (r=0.139; P=0.201), 41-50 years (r=-0.103; P=0.237), 51-60 years (r=0.013; P=0.850), and >60 years (r=-0.150;). P=0.642). There was a weak relation between interspinus distance with axial angulation of S1 (r=0.049; P=0.225). There was a weak relation between height with axial angulation of S1 (r=0.037; P=0.364). Conclusion: The present study, the first of its kind in North Western part of India arrived to help us anthropometric measurements of sacral vestibule, thereby, helping in development of local protocols for percutaneous fixation in sacral fracture.

Paddy and wheat stubble blazing in Haryana and Punjab states of India: A menace for environmental health

AbstractPaddy and wheat cropping is a widespread farming practice in northwestern parts of India, primarily in the riverine plains of Haryana and Punjab. These fertile lands are well known for extensive agricultural fields; however, they are equally infamous for the burning of paddy and wheat straw and stubble by farmers after the harvesting season. In India, it is reckoned that 22,289 gigagrams (Gg) of paddy stubble biomass is generated annually, and of this 13,915 Gg (62.42%) is set ablaze in the agricultural fields. Haryana and Punjab alone produce 48% of the whole straw production in India, which is openly burned in situ. Burning of farm residue emits various trace gases, such as carbon dioxide (CO2), carbon monoxide (CO), methane (CH4), nitrogen oxides (NOX), and sulfur oxides (SOX), as well as huge quantities of particulate matter (PM), including PM of 10 microns or less (PM10) and 2.5 microns or less (PM2.5), into the atmosphere, causing negative impacts on human health and exacerbating global warming. It is estimated that the burning of one metric tonne (2,204.6 pounds) of straw releases 3 kilograms (kg) of PM, 60 kg of CO, 1,460 kg of CO2, 199 kg of ash, and 2 kg of SO2, causing significant global warming and acid rain. The major problems faced by the local people are eye irritation, dryness of eyes, lung diseases, and chest congestion. The National Capital Region (NCR) of Delhi, Haryana, and Punjab faced a disastrous smog impact during October 2016, and November 2017. These incidents led to chronic obstructive pulmonary disease, pneumoconiosis, bronchitis, cataract, corneal opacity, blindness, and air pollution (smog), especially indoor air pollution, which is also a risk factor for developing pulmonary tuberculosis. Because of severe air pollution, Delhi NCR alone experiences approximately 20,000 premature deaths annually. Cases of road accidents also increase during periods of stubble burning due to poor visibility. The emissions also contribute to haze, global warming, and climate change. In India, the National Green Tribunal prohibited this antediluvian farm practice of straw burning in the pollution‐racked city of New Delhi and the adjacent state of Haryana and, just to the northwest, Punjab. One of the methods that can be used to reduce this menace is incorporation of the straw into the soil, which eventually enhances soil fertility. The crop residue material can also be used for compost formation as a traditional approach. In addition, alternate energy resources can be generated from this agro‐biomass. Further, over the past decades, many conversion processes were developed to produce alternate biofuels in different forms (pellets, briquettes) from crop residues. An integrated crop residue management approach is the need of the hour to control this human‐induced catastrophe.

Atlantic Ni\xf1o modulation of the Indian summer monsoon through Asian jet

The Indian rainfall and the Atlantic Niño peaks during summer month and have inverse relationship. This relationship has been revisited in the current study and it is found that the Atlantic Niño significantly influences a dipole pattern of rainfall in the north–east and the north-western parts of India. The positive phase of the Atlantic Niño intensifies the inter-tropical convergence zone, as a result of this local tropospheric warming, over the equatorial east Atlantic and west Africa, owing to the enlargement of the upper-troposphere divergence. This provokes meridional stationary wave owing to the stronger meridional transfer of energy, as the influences of background jet-streams are minimal over North Africa and Europe. This results in the consecutive anomalous negative, positive, and negative geopotential heights (GPHs) over the tropical east Atlantic, Mediterranean, and north–west Europe, respectively. The north–west Europe acts as the center of action for the propagation of a Rossby wave train zonally oriented toward central Asia reinforcing positive GPH anomaly over there. The positive GPH anomaly reduces the Asian subtropical westerly jet-stream east of the Caspian Sea, owing to the reduction in the upper-troposphere divergence toward the Indian subcontinent and caused for above (below) normal north–east (north–west) Indian summer monsoon rainfall. The atmospheric general circulation model captures general characteristics of wave pattern and changes in the Asian jet when correlated with Atlantic Niño with considerable skill.

Modelling the moistening of the free troposphere during the northwestward progression of Indian monsoon onset

Understanding and prediction of Indian monsoon onset is of paramount importance for agricultural planning, which affects food production and the gross domestic product of the country. A recent observational study suggests that the progression of the Indian monsoon onset in a northwestward direction, which is perpendicular to the mean flow, is reinforced by the moistening of the free troposphere by pre‐monsoon showers and wetting of the land surface. As the onset progresses, the mid‐tropospheric dry layer is thought to be constantly moistened from below by detrainment from shallow cumulus and congestus clouds from the southeast. The dry layer becomes much shallower towards southeast India, making the profile closer to moist adiabatic, providing favourable conditions for deep cumulus convection. Increased moistening of the free troposphere thereby pushes the northern limit of moist convection northwestwards. Here, we examine the representation of this process in hindcast simulations from the fully coupled atmosphere–ocean seasonal forecast system of the UK Met Office, GloSea5. The model effectively captures the mid‐level dry‐air intrusion from the northwest that suppresses convection over the northwestern parts of India. We also show that detrainment from shallow convection, measured by moisture tendencies around the freezing level, acts to saturate the free troposphere ahead of the monsoon onset, eroding the dry layer from the southeast. This work suggests that initialized coupled models are capable of simulating dynamic and thermodynamic processes inherent in monsoon progression during the onset.

Low dose computed tomography KUB region for management of urolithiasis in Indian scenario

Background: The incidence, prevalence and recurrence of urolithiasis are very high; especially in the north-western part of India. Ultrasonography has decreased sensitivity and specificity as compared with NCCT for detection of both renal and ureteral calculi. Drawbacks of NCCT in terms of radiation exposure, cost and repeatability can be overcome by Low dose NCCT protocols. Low dose NCCT can be an investigation with high diagnostic accuracy, less radiation hazards and financial acceptability. Aim of this study was to evaluate use of Low dose CT-KUB over ultrasound (US) for diagnosis of urolithiasis, in Indian scenario.Methods: This is a prospective study, at Tertiary Care Hospital. Patients with acute flank pain, who underwent both US and Low dose NCCT within an interval of 24 hours, at Tertiary Care Hospital. Helical CT scanner (Phillips 128 slice medical systems) with exposure factors setting of KVp 120 and mAs 70 was used.Results: A total of 136 Patients with mean age of 33.01 years (range 19-62 years, SD 10.93), were examined with 82(60.29%) males and 54(39.7%) females, average BMI was 25.07(range 17.2 to 35.02). Low Dose NCCT has a sensitivity of 95% (CI of 89.43-98.14%) and specificity of 87.50% (95% CI of 61.65-98.45%) in the diagnosis of urolithiasis. Mean effective dose of radiation administered in low dose CT-KUB was 1.8-2.2 mSv.Conclusions: In view of information, reliability, repeatability, radiation exposure and cost acceptability; unenhanced Low dose CT-KUB region should be the preferred investigation for the management of urolithiasis, in the scenario of a developing country.

Temperature and Precipitation trends in Kashmir valley, North Western Himalayas

Climate change has emerged as an important issue ever to confront mankind. This concern emerges from the fact that our day-to-day activities are leading to impacts on the Earth’s atmosphere that has the potential to significantly alter the planet’s shield and radiation balance. Developing countries particularly whose income is particularly derived from agricultural activities are at the forefront of bearing repercussions due to changing climate. The present study is an effort to analyze the changing trends of precipitation and temperature variables in Kashmir valley along different elevation zones in the north western part of India. As the Kashmir valley has a rich repository of glaciers with its annual share of precipitation, slight change in the temperature and precipitation regime has far reaching environmental and economic consequences. The results from Indian Meteorological Department (IMD) data of the period 1980–2014 reveals that the annual mean temperature of Kashmir valley has increased significantly. Accelerated warming has been observed during 1980–2014, with intense warming in the recent years (2001–2014). During the period 1980–2014, steeper increase, in annual mean maximum temperature than annual mean minimum temperature, has been observed. In addition, mean maximum temperature in plain regions has shown higher rate of increase when compared with mountainous areas. In case of mean minimum temperature, mountainous regions have shown higher rate of increase. Analysis of precipitation data for the same period shows a decreasing trend with mountainous regions having the highest rate of decrease which can be quite hazardous for the fragile mountain environment of the Kashmir valley housing a large number of glaciers.

Temporal variability in aerosol characteristics and its radiative properties over Patiala, northwestern part of India: Impact of agricultural biomass burning emissions

A comprehensive measurements of aerosol optical depth (AOD), particulate matter (PM) and black carbon (BC) mass concentrations have been carried out over Patiala, a semi-urban site in northwest India during October 2008 to September 2010. The measured aerosol data was incorporated in an aerosol optical model to estimate various aerosol optical parameters, which were subsequently used for radiative forcing estimation. The measured AOD at 500 nm (AOD500) shows a significant seasonal variability, with maximum value of 0.81 during post-monsoon (PoM) and minimum of 0.56 during winter season. The Ångström exponent (α) has higher values (i.e. more fine-mode fraction) during the PoM/winter periods, and lower (i.e. more coarse-mode fraction) during pre-monsoon (PrM). In contrast, turbidity coefficient (β) exhibits an opposite trend to α during the study period. BC mass concentration varies from 2.8 to 13.9 μg m−3 (mean: 6.5 ± 3.2 μg m−3) during the entire study period, with higher concentrations during PoM/winter and lower during PrM/monsoon seasons. The average single scattering albedo (SSA at 500 nm) values are 0.70, 0.72, 0.82 and 0.75 during PoM, winter, PrM and monsoon seasons, respectively. However, inter-seasonal and inter-annual variability in measured aerosol parameters are statistically insignificant at Patiala. These results suggest strong changes in emission sources, aerosol composition, meteorological parameters as well as transport of aerosols over the station. Higher values of AOD, α and BC, along with lower SSA during PoM season are attributed to agriculture biomass burning emissions over and around the station. The estimated aerosol radiative forcing within the atmosphere is positive (i.e. warming) during all the seasons with higher values (∼60 Wm−2) during PoM–08/PoM–09 and lower (∼40 Wm−2) during winter–09/PrM–10. The present study highlights the role of BC aerosols from agricultural biomass burning emissions during post-monsoon season for atmospheric warming at Patiala.

Potato Processing: Vital to Agribusiness in Gujarat

Potato (Solanum tuberosum L.), popularly known as ‘the king of vegetables’ is an exotic plant with its centre of origin in high Andes (around Lake Titikaka near Peru and Bolivia border) in South America. It is believed that the Spanish brought it to Europe in early 16th century just to satisfy botanical curiosity and afterwards it attained the status of a food crop in the entire continent. In India, potato was introduced by the Portuguese in the 17th century. In the beginning it was cultivated just as a kitchen garden crop in some western and north-western parts of India. By the early 20th century potato was a cash crop in several parts of the country. Over the years, potato processing has become vital to agribusiness. Gujarat is one of the leading potato producing states in the country. A large number of potato processing units are located in Gujarat which not only provides a ready market for potato grown here but also provide employment to a large number of people and contribute to state GDP.

Deployment of Differential Global Positioning System in Regional Gravity Surveys

This note presents the deployment of differential global positioning system in regional gravity surveys. The high-precision three-dimensional (latitude, longitude and elevation) real-time global satellite navigation system data play a key role in the processing of gravity data in the form of 'elevation correction'. A suitable method has been developed to maintain accuracy in the elevation data and subsequently the gravity observations. The data acquired during this survey are used to map the obvious geological province areas in the northwestern part of India and for the preparation of Bouguer gravity contour map of India with 1 mGal interval under National Geophysical Mapping of the Geological Survey of India in a phased manner.

Holigarna (Anacardiaceae) from the Early Eocene of Western India and its Palaeogeographical and Palaeoclimatological Significance

Abstract: Thick lignite deposits on the western margin of India were preserved on account of thick vegetation which got buried underneath due to tectonic activities that occurred in northwestern part of India during the early Palaeogene. Study of the fossil flora preserved in these beds is important to deduce the palaeoclimate of the region. Therefore, a field work was undertaken to collect plant fossils from the Tarkeshwar lignite mine, Surat district, Gujarat (western India) which is still unexplored as far as the plant mega-remains are concerned. A fossil wood is systematically described from the Cambay Shale Formation of the mine considered to be of early Eocene in age. It shows close affinities with Holigarna (Anacardiaceae), particularly with H. beddomei and H. grahamii. This genus is evergreen in nature and grows in the Indo-Malayan region, while both the modern analogues of the fossil are endemic to semi-evergreen to evergreen forests of Western Ghats, south India, located at the equator. This not only confirms the palaeolatitudinal position of the Indian subcontinent at the equator during the early Palaeogene, but also indicates the presence of equatorial rain forest in the Indian subcontinent during the period. Based on the timetree, Sapindales started to diverge in the early Palaeocene (62– 57 Ma) as its oldest fossil is from the K-Pg boundary. Discovery of the present anacardiaceous fossil (belonging to Sapindales) from the early Eocene strengthens the above phylogenetic view.

Characterization and radiative impact of dust aerosols over northwestern part of India: a case study during a severe dust storm

The present study focused on examining the impact of a severe dust storm (DS) on aerosol properties over Patiala (30.33°N, 76.4°E), a site located in the northwestern part of India during 20th–23rd March, 2012. On 20th March, average PM10 mass concentration increased abruptly from 182 to 817 µg m−3 along with significant increase in the number density of coarser particles (diameter >0.45 µm). During DS, spectral aerosol optical depth (AOD) increases significantly with more increase at longer wavelengths resulting in weak wavelength dependence (AOD at 380 nm increases by ~210 % and at 870 nm by ~270 % on 20th March). Significant decrease in Angstrom exponent (AE; α 380–870) from 0.56 to 0.11 and fine-mode fraction (FMF; PM2.5/PM10) from 0.49 to 0.25 indicates dominance of coarser particles over the station. Net short wave (SW) radiation flux has been decreased by ~20 % and single scattering albedo (SSA675) has been increased from 0.86 (19th March) to 0.90 (20th March). This observation is attributed to additional loading of scattering type aerosols on arrival of DS. Wavelength dependence of SSA reverses during DS and it increases with wavelength due to dominance of coarse-mode particles. Atmospheric aerosol radiative forcing (ATM ARF) during DS ranged from +45 to +77 W m−2, consequently heating the lower atmosphere up to 2.2 K day−1. Significant atmospheric heating rate due to severe dust storm may affect the regional atmospheric dynamics and hence the climate system.

Mean climate and representation of jet streams in the CORDEX South Asia simulations by the regional climate model RCA4

A number of simulations with the fourth release of the Rossby Center Regional Climate Model (RCA4) conducted within the COordinated Regional climate Downscaling EXperiment (CORDEX) framework for South Asia at 50 km horizontal resolution are evaluated for mean winter (December–March) and summer (June–September) climate during 1980–2005. The two driving data sets ERA-Interim reanalysis and the general circulation model EC-Earth have been analyzed besides the RCA4 simulations to address the added value. RCA4 successfully captures the mean climate in both the seasons. The biases in RCA4 appear to come from the driving data sets which are amplified after downscaling. The jet streams influencing the seasonal precipitation variability in both seasons are also analyzed. The spatial and quantitative analysis over CORDEX South Asia generally revealed the ability of RCA4 to capture the mean seasonal climate as well as the position and strength of the jet streams despite weak/strong jet representation in the driving data. The EC-Earth downscaled with RCA4 exhibited cold biases over the domain and a weak Somali jet over the Arabian Sea. Moreover, the moisture transport from the Arabian Sea during summer is pronounced in RCA4 simulations resulting in enhanced monsoon rainfall over northwestern parts of India. Both the Somali jet and the tropical easterly jet become stronger during strong summer monsoon years. However, there is robust impact of wet years in summer over the Somali jet. Wet-minus-dry composites in winter indicate strengthening (weakening) of the subtropical jet in RCA4 run by ERA-Interim (EC-Earth). The driving data have clear reflections on the RCA4 simulations.

Tramadol for maintenance treatment for an elderly "doda" (poppy husk) user

Natural opioids have been in use in the North Western part of India for a long time. We present the case of an octogenarian doda (poppy husk) user, who sought treatment with us due to unavailability of natural opiates. The patient was treated successfully with tramadol maintenance for over 8 months. This case suggests that tramadol can be used as a harm reduction approach, for maintenance of patients with opioid dependence.

Multi-year model simulations of mineral dust distribution and transport over the Indian subcontinent during summer monsoon seasons

Aerosol distribution over the Arabian Sea and the Indian subcontinent during the northern hemispheric summer is dominated by mineral dust transport from the West Asian desert regions. The radiative impact of these dust plumes is expected to have a prominent role in regulating the Asian Summer Monsoon circulation. While satellite observations have provided information in the spatial distribution of aerosols over the oceanic regions during the season, their utility over the land is rather limited. This study examines the transport of mineral dust over the West Asian desert, the Indian subcontinent and the surrounding oceanic regions during the summer monsoon season with the help of a regional scale model, WRF-Chem. Geographical locations of prominent dust sources, altitude ranges of mineral dust transport and their inter-annual variations are examined in detail. Multi-year model simulations were carried out during 2007 to 2012 with a model integration from 15 May to 31 August of each year. Six-year seasonal mean (June to August) vertically integrated dust amount from 1000 to 300 hPa level shows prominent dust loading over the eastern parts of Arabian desert and the northwestern part of India which are identified as two major sources of dust production. Large latitudinal gradient in dust amount is observed over the Arabian Sea with the largest dust concentration over the northwestern part and is primarily caused by the prevailing northwesterly wind at 925 hPa level from the Arabian desert. The model simulations clearly show that most of the dust distributed over the Indo-Gangetic plane originates from the Rajasthan desert located in the northwestern part of India, whereas dust observed over the central and south peninsular India and over the Arabian Sea are mainly transported from the Arabian desert. Abnormal dust loading is observed over the north Arabian Sea during June 2008. This has been produced as a result of the low pressure system (associated with the onset of summer monsoon) which entered in to the Arabian land mass, resulting strong wind and large dust storms over the region; the prevailing northwesterly wind transported these dust in to the Arabian Sea.

Improved understanding of an extreme rainfall event at the Himalayan foothills – a case study using COSMO

In recent years, an increased occurrence of loss and damage of property and human casualties over the southern rim area of the Himalayas, caused by landslides following intense rainfall events, has been reported. An analysis of Tropical Rainfall Measuring Mission (TRMM)-gridded rainfall data shows that events with an exceedance probability of 1.6% for 200 mm/d rainfall are common over this region during the monsoon season. An improved understanding of the mechanisms, which lead to such events, is important for their prediction and to estimate the impact of climate change on their recurrence. In this study, we analyse such an extreme precipitation event, which hit the Uttarakhand region of the central Himalayas on 13 September 2012. We use the operational regional weather forecast model COSMO at a convection-permitting resolution of 2.8 km to simulate this event. The spatial pattern of daily-accumulated precipitation and atmospheric state profiles simulated by the model compared well with the TRMM-gridded data and radiosonde observations, which adds confidence to our model results. Our analysis suggests a three-step mechanism leading to this event: (1) development of an easterly low-level wind along the Gangetic Plain caused by a low pressure system over the central Gangetic Plain; (2) convergence of moisture over the north-western part of India, leading to an increase of potential instability of the air mass along the valley recesses, which is capped by an inversion located above the ridgeline; and (3) strengthening of the north-westerly flow above the ridges, which supports the lifting of the potentially unstable air over the protruding ridge of the foothills of the Himalayas and triggers shallow convection, which on passing through adjacent folds initiates deep convection.

Development and application of an integrated sustainability index for small-holder dairy farms in Rajasthan, India

In agrarian economy of developing nations like India, smallholder dairy production is an important enterprise and its sustainability is vital for ensuring livelihood and nutritional security to the masses. Studies on methodological aspects of farm sustainability at micro-level are limited, either confined to a particular dimension of sustainability or based on complex data requirement which is not feasible to obtain in the context of smallholder dairy farms. This study has developed a multi-attribute farm level sustainability assessment method encompassing economic, social and ecological dimensions of sustainability and has applied it to assess the sustainability of dairy farming in north-western part of India. Based on data from 120 dairy farms located in rural area of Jaipur district from the state of Rajasthan, the study computed the composite Sustainable Dairy Farming Index (SDFI). The overall substantiality status of the smallholder dairy farms in the study area was not encouraging, implying that it may not be viable for future generation to take up the enterprise. Among the three dimensions of sustainability, the average scores of ecological dimension were highest followed by the economic and social sustainability scores. Some of the core attributes like feed productivity, management of animal genetic potential and gender equality are particularly weak aspects of the dairy production system in India. The direct relationship of economic sustainability with herd size suggests for farmers with very small herds (one to two) animals, increasing the number of dairy animals to about five to six, would be a good strategy to economize on input costs and generate more marketed surplus of milk.

Moyamoya disease - A case report from North Western part of India

Moyamoya disease is a chronic, progressive occlusion of the circle of Willis arteries that leads to the development of characteristic collateral vessels seen on imaging, particularly cerebral angiography. The disease may develop in children and adults, but the clinical features differ. Moyamoya disease occurs predominantly in Japanese individuals but has been found in all races with varying age distributions and clinical manifestations. As a result, moyamoya disease has been under-recognized as a cause of ischemic and hemorrhagic strokes in the Indian subcontinent. At this time, there is no known cure, and existing treatment options are controversial. We here describe the case of a 27-year-old Indian presenting as right-sided hemiparesis with accelerated hypertension.

Observational Analysis of Two Contrasting Monsoon Years

Abstract. The Indian summer monsoon rainfall contributes about 75 % of the total annual rainfall and exhibits considerable interannual variations. The agricultural economy of the country depends mainly on the monsoon rainfall. The long-range forecast of the monsoon rainfall is, therefore of significant importance in agricultural planning and other economic activities of the country. There are various parameters which influence the amount of rainfall received during the monsoon. Some of the important parameters considered by the Indian Meteorological Department (IMD) for the study of monsoon are Outgoing Longwave Radiation (OLR), moisture content of the atmosphere, zonal wind speed, low level vorticity, pressure gradient etc. Compared to the Long Period Average (LPA) value of rain fall, the country as a whole received higher amount of rainfall in June, 2013 (34 % more than LPA). The same month showed considerable decrease next year as the amount of rainfall received was around 43 % less compared to LPA. This drastic difference of monsoon prompted to study the behaviour of some of the monsoon relevant parameters. In this study we have considered five atmospheric parameters as the indicators of monsoon behaviour namely vertical relative humidity, OLR, aerosol optical depth (AOD), wind at 850 hPa and mean sea level pressure (MSLP). In the initial analysis of weekly OLR difference for year 2013 and 2014 shows positive values in the month of May over north-western parts of India (region of heat low). This should result in a weaker monsoon in 2014. This is substantiated by the rainfall data received for various stations over India. Inference made based on the analysis of RH profiles coupled with AOD values is in agreement with the rainfall over the corresponding stations.