PG Thesis
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Item Influence of Indian ocean on structure and variability of monsoon low level jet in the present and future climate perspectives(College of climate change and environmental science, Vellanikkara, 2023-11-30) Neha Johnson.; Ruchith , R DThe Monsoon Low-Level Jet (MLLJ) is a crucial synoptic feature of the Indian summer monsoon, responsible for a significant portion of moisture transport to the Indian subcontinent. The present study focuses on analyzing the variability and vertical structure of the Monsoon Low-Level Jet (MLLJ) during the Southwest Monsoon season from 1979 to 2022. To conduct in-depth analysis, the total MLLJ path was divided into five regions: the Southern Indian Ocean, Equatorial Indian Ocean, Arabian Sea, Indian subcontinent, and the Bay of Bengal. The mean jet core height for these selected regions was found to be 588.84 ± 37.81, 874 ± 16.9, 849.62 ± 24.11, 830 ±39.85, 832 ± 41.25 and mean jet speed were found to be 2.96 ± 2.78, 10.49 ± 1.07, 15.79 ± 3.1, 11.43 ± 3.4 and 9.857 ± 3.09 respectively. Monthly variation in the jet properties were also analysed. To consider the impact of global warming on MLLJ characteristics, the analysis was conducted by dividing the study period into two epochs: pre-20 (1979 – 2000) and post-20 (2001 – 2022). The properties of the jet exhibit remarkable differences between these two epochs. Trend analysis also indicates a significant change between these epochs. Jet properties show robust interconnections with sub-seasonal ocean processes, including Somali, Oman, and South Eastern Arabian Sea upwellings in the Indian Ocean. The Arabian Sea Mini Warm Pool exhibits a significant correlation with jet properties, especially Arabian Sea core height.Extensive research was conducted to deeply investigate the pivotal influence of MLLJ characteristics on cloud and precipitation processes. The association of Convective Available Potential Energy (CAPE) and convective precipitation with core height exhibited similarities in the Arabian Sea (AS) and Indian subcontinent (IS) regions, while the Bay of Bengal (BB) region displayed notable differences. The Jet speed exhibits same pattern. In the study, MLLJ characteristics were examined in relation to ocean-atmospheric processes, including the IOD, ENSO, and SIOD indices, with a focus on notable variations in the SIOD index. The MLLJ characteristics also correlate with Indian summer rainfall, showing significant relationships. To assess future prospects, historical (1850-2014) and projection (2015-2096) data from IITM ESM were analyzed in conjunction with jet properties.Item Crop weather relationship studies in bitter gourd(Department of Agricultural Meteorology, College of Horticulture, Vellanikkara, 1996) Lincy Davis, P; Balakrishna Pillai, PAn experiment was conducted during 1995 – 96 at the College of Horticulture, Vellenikkara to find out the optimum date of sowing and to study the crop – weather relationship in bitter gourd, variety mc –84. The experiment was laid out in randomised black design with 3 replications. The treatments consisted of twelve dates of sowing starting from April 15th, 1995 and ending in March, 15th, 1996. For each and every treatment one control plot was maintained. The biometric observations of the crop growth characters, flowering and yield attributes were taken at different stages of development of the crop. The observations on the incidence of pests and diseases were recorded from the control plots. The observations on weather elements were recorded daily. October sowing was significantly superior to others with regard to number of female flower production, number of fruits, fruit set, fruit length girth, weight and yield. The crop weather relationship studies showed that the temperature range during 45 to 65 DAS and sunshine hours during 40-60 DAS were positively correlated with both total yield and number of female flowers per plant while minimum temperature during 45-60 DAS and mean relative humidity during 45-70 DAS were negatively correlated with both total yield and number of female flowers per plant. Crop sown during September, October and November were free from the attack of Bactrocera cucurbitae (Coq.). While Eudioptes indica (Saund.) occurred throughout the year. Mosaic disease incidence was severe in crops sown during June. But September sown crop was free from diseases.Item Forecasting of rice yield using climatological variables(Department of Statistics, College of Veterinary and Animal Sciences, Mannuthy, 1986) Ajitha, T K; Prabhakaran, P VItem Effect of graded doses of nirogen and potash on growth, root yield and alkaloid content of Periwinkle (Catharanthus roseus (L.) G. Don)(Department of Horticulture, College of Agriculture, Vellayani, 1981) Regunath, B R; Sethumadhavan, PAn experiment was conducted at the College of Agriculture, Vellayani during the year1979-80 to study the effect of four levels of nitrogen (50, 100,150 and 200 kg per hectre) and three levels of potash (50, 100 and 150 kg per hectare) in RCBD on the growth, yield and alkaloid content of Periwinkle (Catheranthus roseus (L.) G. Don). Application of N, particularly at higher levels, had significant influence on plant height, girth of stem and tap root, fresh and dry yield of leaves, shoot, root and total alkaloid yield per hectare. Increased application of N increased the percentage of alkaloid content in root and at lower levels it increased the length of tap root, girth and number of lateral roots.Item Water availability and climatic water balance for a selected cropped area(Department of Irrigation and Drainage Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 2018) Venkata Sai, K; Asha JosephItem Regional groundwater resource modelling using modflow - a case study(Department of Irrigation and Drainage Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 2018) Uday Bhanu Prakash; Sasikala, DWater is the basic need for all living organisms and is essential for sustainable development. World is facing a growing demand for high quality water resources while the water availability remains constant. Quantifying the water resources is necessary for efficient use of water resources. Groundwater modelling is a tool used to study the groundwater behavior and quantify the groundwater resource. In this study, Visual MODFLOW was used to study the groundwater behavior and predict groundwater heads at different scenarios in West Godavari district. Andhra Pradesh is known as ‘Rice bowl of India’. East Godavari and West Godavari districts contribute to the maximum production of paddy in Andhra Pradesh. Around 3000TMC of Godavari river is draining into bay of Bengal, whereas flow in Krishna River is in a critical condition. So, Government of Andhra Pradesh planned to divert surplus water in Godavari river to Krishna river using ‘Pattiseema lift irrigation project’. Pattiseema lift irrigation project will pumping around 100 -125 TMC using 24 motors to Godavari river. The main objective of the study is to analyse the spatial and temporal variation of groundwater, identifying the potential groundwater zones to collect the lithology and developing the groundwater flow model for the study area were the different objectives of the study. Spatial and temporal variation of the groundwater heads was studied using a plot between groundwater heads at different locations with respect to time and observed that groundwater vary with respect to topography, climate and soil properties. Potential groundwater zones were identified by developing map using groundwater heads. Different locations were selected and well log was collected from Groundwater and Water audit Department, Government of Andhra Pradesh. From lithology data, it is observed that major portion of the West Godavari district was occupied by sandstone followed by clay, sand, clayey sandstone, granite gneissis and shales. Model is developed using data from 53 head observation wells from 2003 to 2017. 117 A model was developed by assigning all boundaries, aquifer properties and head observation levels. Calibration and validation of the model was done. The model has been used for prediction with different scenarios and also used to study the groundwater behavior at different scenarios. Model was also used to study the effect of ‘Pattiseema lift irrigation project’ on groundwater recharge. After assigning all inputs, the model was calibrated with 2003 to 2005 year data in steady state condition with and 2006 to 2011 data was added for transient state condition. Calibrated model was validated using groundwater heads up to 2017. In validation a new recharge layer is added considering the effect of lift irrigation canal. Validated model was used for prediction. In prediction the effect of decreasing recharge by 5 per cent in every five year for the next fifteen years was studied. The effect of increasing the pumping rate by 5 per cent in every five year for the next fifteen years was also studied. The effect of ‘Pattiseema lift irrigation project was also studied and we observed that considering the lift irrigation project there was an increase in the net recharge from 50 mm/year to 100 mm/year. There was also a 3 m rise in groundwater level nearer to the canal From this study, it was observed that West Godavari district is safe with increase in pumping rate and decrease in recharge up to 2032. This is due to the recharge from rivers and lift irrigation canal. Considering the predicted heads and surface water availability, proper cropping pattern can be adopted to increase productivity. Conjunctive use of surface and groundwater can also be adopted in the study area to solve the water shortage problem. A better understanding of the behavior of the groundwater resources of the area can help in making efficient managerial decisions in futureItem Impact of projected climate change on cropping pattern of agro ecological units of northern Kerala(Academy of Climate Change Education and Research, Vellanikkara, 2018) Yasser, E K; Sunil K MukundanClimate change poses a developing threat to sustainability of social and economic development, livelihoods, and environmental management across the globe. Characterizing the ecosystems using the AEZ concept is a good decision-making approach for variety of farming activities performed by the farmers and is a useful tool for studying the impact of climate change. The objectives of this study are (1) to study rainfall variability and to determine water availability periods of Agro ecological units of southern Kerala under different climate change scenarios. (2) To study the impact of projected climate change on cropping pattern, crop calendar and the possible changes in the water requirements of major cropping systems prevailed in the various Agro ecological Units of northern Kerala. Daily rainfall data for the period 1991-2014 were collected from the India Meteorological Department, Thiruvananthapurm. Weather cock v.1.5 was used for converting the daily weather data into standard week, month and seasonal formats. It is also used to compute PET and Thornthwaite water balances. CROPWAT model was used for the calculations of crop evapotranspiration, crop water requirements and irrigation requirements for the development of irrigation schedules under various management conditions and scheme water supply. The annual rainfall availability in most of the AEUs of Kozhikode, Kannur, Kasaragod and Wayanad districts show an increasing trend in the projected climate. The number of annual rainy days generally shows a linear trend. The seasonal rainfall of southwest and summer monsoon will show an increase from the current situation where as northeast monsoon and winter will have a decreasing trend. In projected climate of both RCP 4.5 and 8.5 the number of months having the surplus and deficit have a similar trend compared to present situation. The crop evapotranspiration values of rice-based cropping system will show a tendency to decrease. In perennial cropping systems of coconut based and rubber the projected crop evapotranspiration will have a reduction from the presentsituation whereas in coffee-based cropping system the ETc will have an increasing trend. The irrigation requirement of all the major cropping systems will increase from the present situation except in the case of rice-fallow-fallow. The length of growing period of the cropping season in the major rice growing areas of different AEUs are getting shorter with slight differences among various agro-ecological units, implying a higher risk of operating under projected climate as per RCP 4.5. The sowing date will be delayed up to three to five weeks. It can be also observed that the crops will have to suffer water stress during the grain filling stage and will be under heavy rains at time of harvest in almost all the considered cases.Item Temporal changes in the weather elements at Panangad region and their influence on the hydrography of a pond(Department of Fishery Hydrography, College of Fisheries, Panangad, 2004) Pronob Das; Raman, N NThe present study was undertaken with a view to finding out the seasonal and diurnal changes of weather elements at Panangad region, seasonal and diurnal changes in the hydrographic parameters of a freshwater pond and finally to understand the possible influence of weather elements on hydrographic conditions of a pond during the four seasons viz. southwest monsoon season (June-September), post monsoon season (October-November), northeast monsoon season (December-February) and pre monsoon season (March-April) at the College of fisheries, Panangad, Cochin. Meteorological data were collected at 03 UTC (0830 IST) and 12 UTC (1730 IST) daily during the period from June 2003 to April 2004. Water samples were collected from a pond every fortnightly to analyse hydrographical parameters. To study the diurnal variation, 24-hour observation were taken at an interval of 3 hrs, once for each season. Meteorological observation includes air temperature, maximum temperature, minimum temperature, total rainfall, relative humidity, cloudiness, wind speed and direction. Hydrographic parameters like water temperature, pH, transparency, water level, total alkalinity, primary productivity, dissolved oxygen, nitrate, nitrite, phosphate and silicate were estimated. There was a considerable seasonal variation in water qualities. The surface temperature closely followed the air temperature and exhibits a clear double oscillation. Low pH values confined to the southwest monsoon period were due to heavy rainfall. pH showed a positive relation with air temperature. At higher temperature evaporation was more and water level decreased, which leads to the higher concentration of plankton bloom and low level of transparency. Presence of nutrient elements in optimum concentration and there by production of phytoplankton and algal bloom may be the possible reason for the high productivity during the northeast and pre monsoon periods. The low values of primary production during southwest monsoon period (June to September) and in October might be due to cloudy conditions before and during the sampling, which reduced light intensity, and along with incessant rains cut down production. The high concentration of alkalinity during pre monsoon may be due to decrease in water level due to evaporation. The effect of rainfall in decreasing bicarbonates is well known. Dissolved oxygen was at the highest level in ponds during colder months and was due to low temperature and intense photosynthetic activities. Subsequent fall of dissolved oxygen in pre monsoon period is attributed to the death and decay of plankton and presence of other organic matter. The plankton population in the pond was highest during the month of December/January to April, coinciding with the higher concentration of alkalinity and nutrients. Diurnal variations in water temperature, pH, dissolved oxygen, alkalinity and primary productivity were well marked. Among nutrients phosphate, nitrate and nitrite did not show any specific pattern, where as silicate concentration showed well-marked short-term variation in all seasons. Weather elements showed significant relationship with many hydrographical parameters and the variations might be due to the combined effects of all those factors. The influence may be direct or indirect. Among the weather elements the influence of air temperature and rainfall was most prominent. The seasonal and diurnal changes in weather elements were equally important for the changes in hydrographical parameters. Shallow water bodies quickly react to the changes in weather elements.