Date of Award
12-1-2023
Language
English
Document Type
Master's Thesis
Degree Name
Master of Science (MS)
College/School/Department
Department of Atmospheric and Environmental Sciences
Dissertation/Thesis Chair
Mathias Vuille
Subject Categories
Atmospheric Sciences
Abstract
The freezing level height (FLH) in the tropical Andes has increased over the past several decades, as is evident with the receding of alpine glaciers in this region. The accuracy of Global Climate Models (GCMs)—specifically previous generations of the Coupled Model Intercomparison Project (CMIP)—in this region remains an issue, as the complex terrain and climate characteristics are difficult to simulate realistically. The changes seen in these tropical alpine glaciers in the past few decades are a clear indicator of the effects climate change is having in this tropical mountain region, making it important to better understand current and projected future glacial changes in the area. In this study, we use different atmospheric reanalysis products to examine historical changes of FLH in four glacierized regions of the tropical Andes: Antisana in Ecuador, Cordillera Blanca in Peru, Quelccaya Ice Cap (QIC) in Peru, and Zongo in Bolivia. The changes in FLH estimated by the reanalysis products for each site are compared to historical simulations from 35 CMIP6 models using different metrics such as mean biases and standard deviation. This comparison allows us to better constrain future projections by performing bias correction and by narrowing the number of models to those that have an equilibrium climate sensitivity (ECS) within the IPCC AR6 likely range of 2.5°C - 4°C. By utilizing the significant linear relationship between FLH and equilibrium line altitude (ELA), we estimate the lifetime of the accumulation zone of glaciers in this region to better understand the impact of climate change on the glaciers of the tropical Andes. This project found that by 2100, Quelccaya Ice Cap will likely be shrinking rapidly with no hope of gaining mass. Under the high-emissions scenario SSP5-8.5, Antisana and Artesonraju Glaciers will lose their accumulation zones by 2100, with Zongo Glacier not too far behind.
Recommended Citation
Turner, Shelby, "An Investigation Into Past And Future Freezing Level Height And Equilibrium Line Altitude In The Tropical Andes Using Cmip6" (2023). Legacy Theses & Dissertations (2009 - 2024). 3257.
https://scholarsarchive.library.albany.edu/legacy-etd/3257
