Ph.D. First paper Abstract
Tittle: Quantifying glacier area changes using object-based image analysis in Google Earth Engine
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Presented at the EGU-2022:
https://doi.org/10.5194/egusphere-egu22-6853
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Glaciers are an important component of the cryosphere and are key indicators of climate change. Observations of temporal changes in glacier extent are essential for understanding the impacts of climate change, but these observations are not widely available in many parts of the world. Research indicates that climate change has had a significant impact on glacier recession, particularly in the Arctic, where glacier meltwater is an important contributor to global sea-level rise. Therefore, it is important to accurately quantify glacier recession within this sensitive region. In this study, we mapped 480 glaciers in Russian Arctic, Novaya Zemlya, using object-based image analysis (OBIA) applied to multispectral Landsat satellite imagery in Google Earth Engine (GEE) to quantify the area changes between 1986-89 to 2019-21. Our results confirm that in 1986-89, the total glacierized area was 22958.98 km2 and by 2019-21 there was an 5.56% reduction in glacier area to 21680.63 km2. Comparison between manually corrected glacier outlines taken from the Randolph Glacier Inventory (RGI) and the mapped glacier outlines derived using the OBIA method shows there is a 90.26% similarity between both datasets. This confirms that OBIA, combined with the GEE platform, is a promising method for accurately mapping glaciers, reduces the time required for manual correction, and can be applied in other glacierized regions for rapid assessment of glacier change.
Ph.D. Second Paper Abstract
Tittle: Decadal glacier area changes in the Arctic using object-based image analysis in Google Earth Engine
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Presented at the AGU-2022:
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Climate change has had a significant impact on glacier recession worldwide, contributing disproportionately to global sea-level rise. Due to Arctic amplification, glaciers in the Arctic are retreating faster than at lower latitudes. To better understand the impact of climate change on glaciers in the Arctic, observations of temporal changes in glacier extent are necessary, but these observations are not widely available due to the large effort required in accurately mapping glacier area. In this study, we mapped 1723 glaciers in Baffin Island, Canadian Arctic, Disko Island (Qeqertarsuaq), Greenland and Kenai, Alaska, using Object-Based Image Analysis (OBIA) applied to multispectral Landsat satellite imagery in Google Earth Engine (GEE) to quantify the glacier area changes over three decades. The results shows that the overall loss of glaciers in Baffin is 452±227 Km2 (-6.6%), Disko Island glaciers decrease by 23.6% (-457±168 km2), while Kenai Alaska glaciers showed a 196±84 km2 (-25.7%) decline in the total area. A total of 70 glaciers have completely retreated, including sixty-nine on Disko Island and one in Kenai Alaska. The accuracy of the automatically generated outlines was evaluated by comparing with manually corrected outlines (reference data) using a random sampling approach, resulting in an overall accuracy estimate between 93% and 98% with the reference data. This indicates that the method used in GEE has the potential for rapid glacier mapping and can be easily used in other glacierized regions.