PG Thesis
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Item Global change and subterranean ecosystems of Kerala(College of Climate Change and Environmental Science , Vellanikkara, 2023-01-31) Arya Shaji; Rajeev RaghavanItem Assessment of marine plastics n selected blue carbon ecosystems along the Indian coast(College of Climate Change and Environmental Science, Vellanikkara, 2023-01-30) Subadra, K M; Ratheesh Kumar, RItem Future projections of Indian summer monsoon rainfall in CMIP6(College of Climate Change and Environmental Science, Vellanikkara, 2022-11-30) Lekshmi, M S; Roxy Mathew KollThe state-of-the-art climate model simulations of the Indian monsoon must be examined since future climate policy choices rely on accurate monsoon projections. This study examines the fidelity of 22 CMIP6 models in simulating the Indian summer monsoon from 1950 to 2014. The models are rated based on how well they reproduce seasonal mean precipitation and monsoon circulation characteristics. The multimodel mean of the better models reported in this study is expected to give more reliable Indian monsoon estimates. The Indian summer monsoon's near-term, mid-term, and long-term variations have been studied under SSP1-2.6, SSP2-4.5, and SSP5-8.5 scenarios. According to the findings, future changes in Indian monsoon rainfall are closely tied to changes in low level monsoon winds. Under a global warming scenario, the low level monsoon wind over the North Arabian Sea (north of 15°N) is expected to strengthen, whereas the low level monsoon wind over the South Arabian Sea (south of 15°N) is expected to weaken. This pattern is caused by a poleward shift in the low-level monsoon. This poleward shift causes changes in precipitation over land and ocean. Long-term strengthening of the North Arabian Sea wind speed would result in enhanced rainfall over central India as well as the sinking of air (reduced rainfall) south of the equator, completing the cycle. The quantity of rainfall that may fall on the southern peninsula as a result of global warming, however, will be limited by a decrease in the South Arabian Sea wind speed. Weak winds (south of 15°N) will hinder the moisture buildup caused by the warming of the West Indian Ocean from reaching the subcontinent; rather, it will rise above the ocean, causing an increase in rainfall over the Arabian Sea. Keywords: CMIP6, Indian Summer Monsoon Rainfall, Monsoon Circulation, Climate ProjectionsItem Carbon sink potential of selected forest plantations in Kerala(College of Climate Change and Environmental Science, Vellanikkara, 2023-04-27) Karthik, M S; Sandeep, SNowadays the global climate is changing due to the accumulation of carbon dioxide due to fossil fuel emissions and anthropogenic activities. Forest ecosystems can act as both source and sink of carbon and thus play a crucial role in global carbon cycles. Also, it is one of the most carbon rich habitats on the planet, and their protection is vital in reducing the greenhouse gases in the atmosphere. The objective of the study is to assess baseline scenarios and determine the carbon storage potentials of the selected forest plantations under the Kerala Forest development corporation (KFDC). The study was conducted in the selected forest plantations Marottichal and Kulathupuzha under the Kerala Forest development Corporation. Teak and acacia are considered as the major plantation at Marottichal and sandal mixed plantation was selected in the Kulathupuzha range. The estimation of carbon storage in these plantations was conducted by non-destructive methods. The methods employed included measuring the GBH of the trees, collecting soil from different depths across the profile, and collecting litter and undergrowth from the plots. The GBH data obtained from the field measurements were used as inputs for the allometric equations of the trees thus giving its biomass. In teak plantations, 2008, 2009 and 2010 planted trees showed a carbon storage of 230.85, 216.31 and 239.67 (t/ha) respectively. In all the soil profiles, there was a significant decrease in organic matter content with depth. On the other hand, eight-year-old (2014) acacia plantation accounts for 234.07 t/ha carbon. Soil organic carbon accounts for the major carbon pool (134.64 t/ha). Twelve-and eleven – year – old sandal mixed plantations showed relatively lesser carbon storage than teak and acacia, accounting for 133.51 and 122.19 (t/ha) carbon. This is because the above ground pools accounted for very limited contributions to the carbon storage caused by slow growth of sandal trees. The present study data of carbon storage potential of selected plantations could be added to the data repository and would be useful in carbon accounting during implementation of projects such as Carbon Neutral Kerala.Item Energy analysis of rice cultivation in kole lands of Thrissur district(College of Climate Change and Environmental Science, Vellanikkara, 2022-12-30) Resmi Dhanapal; Mary Regina, FA study was conducted to analyse the energy input and output of rice cultivation in the Kole lands of Thrissur district of Kerala. A total of 358 farmers belonging to two different Padashekharam were surveyed for the study. Two Padashekharams namely Sangam Padashekharam and Porathur Padav Padashekharam were selected for the survey. The persolal details, operational details and machinery details were collected through face-to-face interview. Energy input by human labour, fuel, machinery, electricity, pesticide, fertilizers and energy output as grain and straw were estimated. All the quantified inputs were transformed into energy values using their respective equivalent energy coefficients. Energy efficiency, energy productivity, specific energy and net energy were calculated using standard procedures. The energy inputs were divided into direct energy, indirect energy, renewable energy, non-renewable energy, commercial energy and non-commercial energy. The inputs were also used to find the carbon emission from the field. The results show that the Sangam Padashekharam has a greater energy consumption than Porathur Padav Padashekharam. However, the grain yield is found to be greater in Sangam Padashekharam. The total input and output of Sangam Padashekharam are 33959.53 MJha-1 and 198912.5 MJha-1 respectively, whereas the total input and output of Porathur Padav Padashekharam are 25782.75 MJha-1 and 92225 MJha-1. The energy pattern consists of 34% fertilizers, 26% electricity, 16% diesel, 8% chemical, 8% human labour, 5% seed and 3% machinery. The specific energy, net energy, energy efficiency and energy productivity in this region was 0.51 MJkg-1, 115697.62 MJha-1, 4.71 and 2.31KgMJ-1 respectively. It was also found that the methane emission from paddy field is the largest contributor to carbon emission than any other inputs used for paddy cultivation and it is about 1078.514 kgCO2 eq. The second major contributor is electricity which is about 551.915 kgCO2 eq. The findings revealed that the energy input for fertilizer is higher in the Kole region. This higher input was due to farmers’ practice of applying fertilizer at rates higher than the PoP recommendation. Energy consumption and production costs can be reduced by using the recommended amount of fertilizer. The second highest energy input is electricity, which can be reduced by using a more efficient pump.Item Influence of climatic variables on selected marine fish populations in south estern Arabian Sea(College of Climate Change and Environmental Science, Vellanikkara, 2023-01-27) Reshma, R; Najmudeen, T MThe potential impacts of climate variables on commercially important marine fish population in the southeastern Arabian Sea are mostly unexplored. There are large knowledge gaps that prevent a comprehensive understanding the impacts of climatic variables from the other factors which influence the fish biomass and catches is vital for studying the stock dynamics of fishery resources. The study used Biomass Dynamic Models to investigate relationships between environmental variables and the biomass of commercially important fish species along southwest coast of India and to predict their future changes under various RCP scenarios. For modeling, the time-series data on species/resource wise, gear-wise annual catch and fishing effort for the harvest of selected fishery resources for the period 1985-2019 were used, along with the environmental variables such as annual average data on Sea Surface Temperature (SST), Coastal Upwelling Index (CUI), Marine Heat Waves (MHW) and precipitation (PPT). The results indicate that the models attempted for all the fish groups gave very good fit as observed by the regression plots of observed catch against expected catch with high regression coefficients. The biomass estimated using the model parameters indicate that, the climate variables considered in the present study showed significant lagged effects on biomass of the fish species in varying intensities. The SST component in the biomass was highest for the pelagic fish species ribbonfishes and the contribution to biomass due to SST ranged from 25.7% to 26.4% with an average of 26.0%, and lowest for squids. In general, the influence of SSST on the biomass of two pelagic species are greater that of the demersal species. The influence of precipitation on the biomass of the fish species selected for study were always lower than that of SST both in pelagic as well as demersal resources. The influence of CUI and MHW were much lower in all the species studied compared to that of SST and precipitation, with MHW became the least influencing variable. The predicted biomass tends to decrease over the future periods in the SST model, and increase for the precipitation along the region. In both the projections, lowest values were observed for RCP 6 and highest values for RCP 8.5 scenario for all the species. Coupled with overexploitation, and habitat degradation, climate change impacts are reported to cause challenges in the sustainability of marine ecosystems and fisheries along the coastal waters of India. Present study throws light on the use of biomass dynamics models to unravel the effects of climate variables on the fish biomass and the results indicate that the dynamics of climate variables should also be taken into consideration while determining the harvestable potential of each fishery resource, especially, for the pelagic fish stocks.Item Soil erosion risk assessment in a sub-watershed of karuvannur river basin, Thrissur Kerala using rusle model(College of Climate Change and Environmental Science, Vellanikkara, 2023-05-09) Akash, P J; Mary Regina, FA study was conducted to assess the soil erosion risk regions of a sub-watershed and to classify the whole area based on the severity of the erosion rate classes. Kurumali watershed in the Karuvannur river basin in Thrissur district of Kerala, India was selected for the study. The RUSLE soil erosion model is used to calculate the annual value o soil loss and the intensity of soil erosion. The ArcGIS software was used to implement the RUSLE factors. Parameters like Rainfall erosivity factor (R ), Soil erodibility factor (K), Slope length steepness factor (LS), Cover management factor ( C), and Practice factor (P ) were used for the estimation of soil erosion or the working of the RULE model. The Digital Elevation Model (DEM) of the sub-watershed was used to estimate the LS factor. The land use data of the sub-watershed, collected from Kerala State Land Use Board, were used for estimating the C factor and P factor. 20-year (2000-2020) daily rainfall data of two stations (Pudukkad and Varandarapilly) were collected from Irrigation Design and Research Board (IDRB) for calculating R factor. Soil samples were collected from various physiographic units in the Kurumali watershed for evaluating soil organic matter, texture, structure, and permeability and these were used to calculate the K factor. The soil erosion risk map was produced in the ArcGIS environment after analysing the RUSLE parameters, R, K, LS, C and P. The maps were converted to raster format using a raster calculator and then combined to produce the soil erosion model. The soil loss values for the Kurmali watershed range from 0 to 70.26 tonnes ha-1y-1 with a standard deviation of 1.24. The average soil erosion rate estimated for the watershed ranges between 0 to 1 tonnes ha-1year-1. It was found that about 82.5% of the area (34969.86 ha) comes under the ‘Very slight’(<1 tonnes ha-1 year-1 ) soil erosion class. 11.1% of areas are classified under ‘Slight’ erosion. The ‘Moderate’ erosion class has an area coverage of 1.97%. About 4.42% of the area is under the ‘Moderately high’ to ‘Very high’ (>10 tonnes ha-1 year-1). Among different land use types barren lands has the highest erosion rate followed by plantations. And dense forest has the least erosion rate, due to its dense canopy cover. Measures must be taken to reduce the soil erosion of the study area. Some practices that can be performed to prevent soil erosion in the study area have been suggested.Item Mangrove resource assessment through participatory mapping(College of Climate Change and Environmental Science, Vellanikkara, 2022-12-27) Gopika Shibu; Deepak Samuel, VMangroves are one of the most productive ecosystems which provide aquatic biodiversity conservation, infrastructure protection, livelihood support, climate change mitigation, and adaptation. Due to these services, this unique ecosystem is considered as a biological hotspot but they are in a declining state. For the conservation and management of this ecosystem, assessment of resource use and ecosystem services with the involvement of the local community are essential. The local community are the primary resource users and the chance of exploitation is higher from them, but on the other side, they are the one who plays a major role in the conservation process. The most effective management of resources is possible only with the involvement of the local community. In this study, the resource assessment of mangroves in the Thrissur district of Kerala has been done with the involvement of the local community. A total of four villages have been done. A total of four villages have been selected, two from each the north and south region of the district. Participatory coastal resource assessment (PCRA) tools have been used in this study to compact the local knowledge, resource use, and experience for the management of mangrove resources. Participatory resource mapping exercise, transect walk, and assessment of ecosystem services with the local community have been done. Historical change of mangrove patches with the help of Google Earth also assessed. This study will be helpful for community-based mangrove management to support local and regional decision-making processes.Item Monitoring soil carbon stocks and their thermal stability in the mangrove systems of Kerala(College of Climate Change and Environmental Science, Vellanikkara, 2023-01-24) Abhirami, S R; Sandeep, S