Study of the Seasonal Water Cycle over the Indian Subcontinent and the Southern Ocean using Stable Isotopes in Rainwater and Water Vapor
Stable isotope ratios in rainwater and water vapor act as a tracers of the hydrological cycle. The data on stable isotopic composition in rainwater and water vapor are limited due to the lack of observational studies across the Indian subcontinent and over the ocean. These present day observations a...
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ftiiscdiss:oai:etd.iisc.ac.in:2005/2829 2023-05-15T18:25:06+02:00 Study of the Seasonal Water Cycle over the Indian Subcontinent and the Southern Ocean using Stable Isotopes in Rainwater and Water Vapor Rahul, P Ghosh, Prosenjit 2016 application/pdf http://etd.iisc.ac.in/handle/2005/2829 http://etd.iisc.ac.in/static/etd/abstracts/3679/G27885-Abs.pdf en_US eng G27885 http://etd.iisc.ac.in/handle/2005/2829 http://etd.iisc.ac.in/static/etd/abstracts/3679/G27885-Abs.pdf Indian Subcontinent Hydrological Cycle Southern Ocean Seasonel Time Scales Rainwater Isotopes Stable Isotope Analysis Water Vapor Isotopes Stable Isotopes in Water Cycle Hydrology Thesis 2016 ftiiscdiss 2022-02-22T11:37:00Z Stable isotope ratios in rainwater and water vapor act as a tracers of the hydrological cycle. The data on stable isotopic composition in rainwater and water vapor are limited due to the lack of observational studies across the Indian subcontinent and over the ocean. These present day observations are important database to deduce the paleo-climatic condition from geological archives. In majority of the cases, isotopic records are translated into physical factors with the present background knowledge where relationships with physical variables are well established. In case of tropical region, the primary controlling factor identified behind the stable isotopic variations is the amount of rainfall. However recent observations contradict such relationships challenging the role of amount effect and identified source moisture effect on stable isotope ratios in rainwater at Indian stations. The thesis investigated the amount effect relationship of isotopes at seasonal time scales. The long period observation covering 4 years, where daily time interval rainwater samples collected were used for our study. We used two different station locations; Thiruvananthapuram and Bangalore, where monsoonal rainfall is received for Southwest and Northeast periods. The role of mesoscale and synoptic convection and rainout along the transport pathways were found responsible for the isotopic variance. The role of moisture source regions, rainout over the advection pathways, high rainfall producing systems such as depression and cyclones, and continental recycling of water on rainwater and water isotopes ratios were major findings of the thesis work which are detailed in the chapters. Upon knowing the atmospheric and oceanic condition at the moisture source region based on satellite data and reanalysis data set we modeled our observations using the governing equations of isotope fractionation and well accepted Rayliegh’s distillation model. The observations on rainwater and water vapor isotope ratios in oceanic region are extremely limited due to difficulties in conducting sampling. Water vapor and rainwater observations over the Southern Ocean during the expedition of 2013 and estimation of the moisture recycling across the latitudes over the oceanic regions is a novel work in this thesis. Thesis Southern Ocean Indian Instiute of Science, Bangalore: etd@IIsc (Electronic Theses and Disserations) Indian Southern Ocean |
institution |
Open Polar |
collection |
Indian Instiute of Science, Bangalore: etd@IIsc (Electronic Theses and Disserations) |
op_collection_id |
ftiiscdiss |
language |
English |
topic |
Indian Subcontinent Hydrological Cycle Southern Ocean Seasonel Time Scales Rainwater Isotopes Stable Isotope Analysis Water Vapor Isotopes Stable Isotopes in Water Cycle Hydrology |
spellingShingle |
Indian Subcontinent Hydrological Cycle Southern Ocean Seasonel Time Scales Rainwater Isotopes Stable Isotope Analysis Water Vapor Isotopes Stable Isotopes in Water Cycle Hydrology Rahul, P Study of the Seasonal Water Cycle over the Indian Subcontinent and the Southern Ocean using Stable Isotopes in Rainwater and Water Vapor |
topic_facet |
Indian Subcontinent Hydrological Cycle Southern Ocean Seasonel Time Scales Rainwater Isotopes Stable Isotope Analysis Water Vapor Isotopes Stable Isotopes in Water Cycle Hydrology |
description |
Stable isotope ratios in rainwater and water vapor act as a tracers of the hydrological cycle. The data on stable isotopic composition in rainwater and water vapor are limited due to the lack of observational studies across the Indian subcontinent and over the ocean. These present day observations are important database to deduce the paleo-climatic condition from geological archives. In majority of the cases, isotopic records are translated into physical factors with the present background knowledge where relationships with physical variables are well established. In case of tropical region, the primary controlling factor identified behind the stable isotopic variations is the amount of rainfall. However recent observations contradict such relationships challenging the role of amount effect and identified source moisture effect on stable isotope ratios in rainwater at Indian stations. The thesis investigated the amount effect relationship of isotopes at seasonal time scales. The long period observation covering 4 years, where daily time interval rainwater samples collected were used for our study. We used two different station locations; Thiruvananthapuram and Bangalore, where monsoonal rainfall is received for Southwest and Northeast periods. The role of mesoscale and synoptic convection and rainout along the transport pathways were found responsible for the isotopic variance. The role of moisture source regions, rainout over the advection pathways, high rainfall producing systems such as depression and cyclones, and continental recycling of water on rainwater and water isotopes ratios were major findings of the thesis work which are detailed in the chapters. Upon knowing the atmospheric and oceanic condition at the moisture source region based on satellite data and reanalysis data set we modeled our observations using the governing equations of isotope fractionation and well accepted Rayliegh’s distillation model. The observations on rainwater and water vapor isotope ratios in oceanic region are extremely limited due to difficulties in conducting sampling. Water vapor and rainwater observations over the Southern Ocean during the expedition of 2013 and estimation of the moisture recycling across the latitudes over the oceanic regions is a novel work in this thesis. |
author2 |
Ghosh, Prosenjit |
format |
Thesis |
author |
Rahul, P |
author_facet |
Rahul, P |
author_sort |
Rahul, P |
title |
Study of the Seasonal Water Cycle over the Indian Subcontinent and the Southern Ocean using Stable Isotopes in Rainwater and Water Vapor |
title_short |
Study of the Seasonal Water Cycle over the Indian Subcontinent and the Southern Ocean using Stable Isotopes in Rainwater and Water Vapor |
title_full |
Study of the Seasonal Water Cycle over the Indian Subcontinent and the Southern Ocean using Stable Isotopes in Rainwater and Water Vapor |
title_fullStr |
Study of the Seasonal Water Cycle over the Indian Subcontinent and the Southern Ocean using Stable Isotopes in Rainwater and Water Vapor |
title_full_unstemmed |
Study of the Seasonal Water Cycle over the Indian Subcontinent and the Southern Ocean using Stable Isotopes in Rainwater and Water Vapor |
title_sort |
study of the seasonal water cycle over the indian subcontinent and the southern ocean using stable isotopes in rainwater and water vapor |
publishDate |
2016 |
url |
http://etd.iisc.ac.in/handle/2005/2829 http://etd.iisc.ac.in/static/etd/abstracts/3679/G27885-Abs.pdf |
geographic |
Indian Southern Ocean |
geographic_facet |
Indian Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_relation |
G27885 http://etd.iisc.ac.in/handle/2005/2829 http://etd.iisc.ac.in/static/etd/abstracts/3679/G27885-Abs.pdf |
_version_ |
1766206325481537536 |