Overview
Dr. Jonathan “Johnny” Ryan is a glaciologist who is interested in ice sheet surface processes. His research has investigated several key components that influence the accumulation and ablation of ice sheets, including snowfall, clouds, melt-albedo feedbacks, and supraglacial hydrology. To conduct this research, Johnny primarily relies on satellite remote sensing. This expertise has earned him selection onto NASA’s ICESat-2 and Terra/Aqua/Suomi Science Teams. Johnny also conducts field research and has spent many summers surveying ice sheets and glaciers with uncrewed aerial systems (UAS) or drones. His primary research site is the Greenland Ice Sheet, where he has worked out of Kangerlussuaq and Uummannaq. He has also conducted research on the Northern Patagonia Icefield and the Oregon Cascades. By combining fieldwork with new satellite remote sensing technology, Johnny’s research bridges spatial and temporal scales to generate new insights into ice sheet surface processes. The significance of his research is reflected by recent first- and second-author publications in journals such as Nature, Environmental Research Letters, Science Advances, Nature Communications, and Geophysical Research Letters.
Current Appointments & Affiliations
Recent Publications
Mechanisms of Surface Meltwater Ponding and Drainage on the Greenland Ice Sheet Revealed Using SkySat Imagery and Deep Learning
Journal Article Agu Advances · April 1, 2026 Surface meltwater impacts Greenland Ice Sheet mass balance indirectly by reducing albedo and promoting hydrofracture. However, fully understanding both processes requires accurate mapping of small-scale features such as ponds, channels, and moulins that go ... Full text CiteRevisiting Trends in Greenland Ice Sheet Albedo Using the Combined MODIS and VIIRS Record
Journal Article Earth and Space Science · March 1, 2026 The MODerate resolution Imaging Spectroradiometer (MODIS) instruments onboard NASA's Aqua and Terra satellites have been used to monitor trends in Greenland Ice Sheet albedo for over two decades. These satellites, however, are nearing the end of their prod ... Full text CiteGreenland ice sheet runoff reduced by meltwater refreezing in bare ice.
Journal Article Nature communications · September 2025 The contribution of Greenland Ice Sheet meltwater runoff to global sea-level rise is accelerating due to increased melting of its bare-ice ablation zone. There is growing evidence, however, that climate models overestimate runoff from this critical area of ... Full text CiteRecent Grants
Constraining surface water radiative feedbacks on the Greenland Ice Sheet using very high resolution imagery
ResearchCo Investigator · Awarded by National Aeronautics and Space Administration · 2026 - 2027Retrieval of glacier ice and snow properties over the Greenland Ice Sheet from ICESat-2
ResearchPrincipal Investigator · Awarded by National Aeronautics and Space Administration · 2025 - 2027Role of clouds on Greenland Ice Sheet surface melt
ResearchPrincipal Investigator · Awarded by National Aeronautics and Space Administration · 2024 - 2026View All Grants