Exploring the impact of El Niño and La Niña on δD and δ18O patterns in global precipitation using ArcGIS software

Title

Exploring the impact of El Niño and La Niña on δD and δ18O patterns in global precipitation using ArcGIS software

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Description

This study aims to determine the impact of El Niño Southern Oscillation (ENSO) events on the environmental factors (including temperature, latitude, elevation and precipitation amount) controlling stable isotopes in precipitation utilizing regression models in the ArcGIS software. Stable isotope ratios (δD and δ18O) of precipitation have been documented to be directly dependent on changes in temperature and precipitation amount in temperate and tropical regions of the world, respectively (Dansgaard, 1964). During El Niño and La Niña Southern Oscillation events, many regions of the world experience changes to temperature and precipitation amount, with some regions becoming cooler and wetter, others becoming warmer and drier, and many others experiencing patterns in between (Trenberth, 1997). Using ArcGIS, global maps will be created showing the variation in δ18O, temperature, latitude, elevation and precipitation amount for six selected years corresponding to strong El Niño, strong La Niña, and normal climatic conditions. Regression models will be performed by climate zone of the world (temperate, tropical, polar) to determine the relationship between environmental factors and δ18O. For normal years, the relationship between temperature and δ18O in temperate regions should be approximately linear (R2~1) and a positive trend, while the relationship between precipitation amount and δ18O in tropical regions should show a negative trend. The δ18O ratios in regions of the world that become cooler and wetter during ENSO events could be more depleted than during normal years, while regions that become warmer and drier will have more enriched ratios than during normal years. This project has immense significance in its potential to predict future patterns of δ18O globally during ENSO events, impact groundwater mass balance models, influence resource allocation in regions heavily impacted by ENSO events, and produce more accurate isotope-based paleoclimatic reconstruction models.

Publication Date

4-18-2018

Project Designation

Capstone Project

Primary Advisor

Shuang-Ye Wu

Primary Advisor's Department

Geology

Keywords

Stander Symposium poster

Comments

Presenter: Amber Johnson

Exploring the impact of El Niño and La Niña on δD and δ18O patterns in global precipitation using ArcGIS software

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