Alex Winkler : Alexander von Humboldt Fellow

Alex Winkler

Alexander von Humboldt Fellow

Alex's research focuses on the interactions and feedbacks between the atmosphere and the land surface and its ecosystems, and how the system responds to increasing CO2. He studied Climate System Science at the University of Hamburg, Germany, and worked on the climate sensitivity of CO2 fluxes from permafrost regions in his master thesis. In 2019, he completed his PhD at the Max Planck Institute for Meteorology (MPI) under the supervision of Prof. Brovkin and Prof. Myneni (U. Boston) on the question of what causes the greening trend of the Earth's land surface in satellite observations and Earth system models. In 2020, he moved to the MPI for Biogeochemistry, where he established a junior research group focusing on the land-atmosphere coupling of carbon, water, and energy fluxes. The group uses and develops models of varying complexity that incorporate various Earth observation data streams through machine learning. In 2021, he was awarded the Feodor Lynen Alexander von Humboldt Fellowship to work with Ralph Keeling at Scripps Institution of Oceanography. The project aims to understand what causes phase shifts in the seasonal atmospheric CO2 cycle.

Julia Dohner : Graduate Student

Julia Dohner

Graduate Student

Julia earned her bachelor’s degree in Chemistry at Pomona College in Claremont, CA. Her work as a Ph.D. candidate at Scripps involves global and coastal carbon cycling as well as seawater carbon measuring techniques.

Yuming Jin : Graduate Student

Yuming Jin

Graduate Student

Yuming Jin received his B.S. in Environmental Science from Donghua University in 2018, where he studied wastewater remediation. After undergrad, Yuming joined the Keeling lab and is working on interpreting long-term atmospheric CO2 and O2 measurements in terms of changing global climate and biogeochemistry. Yuming is particularly interested in studying the interaction between the carbon cycle, large-scale atmospheric dynamics, and climate change.

Madat Sardarly : Graduate Student

Madat Sardarly

Graduate Student

Madat received his B.S. majoring in Geophysical Engineering from the University of Strasbourg (UFAZ branch). During his undergraduate studies, he worked on detection of greenhouse gases using satellite imagery and meteorological data. Madat joined the Keeling lab in Fall 2022 and is interested in exploring greenhouse gases in both regional and global scale.

Tim Lueker, Ph.D. : Specialist

Tim Lueker, Ph.D.


Tim began working in the Carbon Dioxide Group at Scripps in 1983, measuring dissolved inorganic carbon (DIC) and Alkalinity in seawater. He earned his Ph.D. under C.D. Keeling in 1998, and then began a postdoc with Ralph Keeling establishing a measurement site for atmospheric O2/N2 and CO2 in Trinidad CA. His specialties include measurements of O2/N2 and CO2 ratio, CO2, and other greenhouse gases in air, and the inorganic carbon chemistry of seawater. He also installs and maintains instruments in Hawaii, helping to document the rising levels of CO2 in a time series popularly referred to as the "Keeling Curve".