Yunyan Zhang


Portrait of  Yunyan Zhang
  • Title
    Scientist, Leader of Climate Analysis Group
  • Email
  • Phone
    (925) 422-5778
  • Organization


It has always been fascinating for me to study the life cycle of clouds. My research interests include diurnal cycle, low-level stratiform clouds, shallow cumulus, shallow to deep convection transition, cloud climate feedback, and the interactive processes between land surface, atmospheric boundary layer and clouds.

I made observational analysis for mechanistic understanding of clouds and convection using satellite data and both in-situ and remote sensing data from field campaigns and long-term observations at DOE ARM climate facilities. I performed numerical modeling and analysis using fine-scale modeling tools such as large eddy simulations and single column models. I diagnosed model performance for validation and improvement, including traditional low-resolution global climate models with parameterized cloud and convection processes, Multi-scale Modeling Framework (MMF) with super-parameterization, and high-resolution kilometer grid scale global storm resolving models (GSRMs). I also used to develop forcing data sets to drive cloud resolving model or single-column model through constrained variational analysis to support DOE ASR cloud modeling activities for various field campaigns.

Ph.D., Atmospheric and Oceanic Sciences, University of California at Los Angeles

B.S., Atmospheric Sciences, Peking University, Beijing, China


Tian, J., Y. Zhang, S. A. Klein, R. Ӧktem, & L. Wang, 2022: How does land cover and its heterogeneity length scales affect the formation of summertime shallow cumulus clouds in observations from the US Southern Great Plains? Geophys. Res. Lett.49, e2021GL097070.

Tian, Y., Y. Zhang, S. A. Klein, 2022: What determines the number and the timing of pulses in afternoon precipitation in Green Ocean Amazon (GoAmazon) observations? Geophys. Res. Lett. 49, e2021GL096075,

Tao, C., Y. Zhang, Q. Tang, H.-Y. Ma, V. P. Ghate, S. Tang, S. Xie, and J. A. Santanello, 2021: Land–Atmosphere Coupling at the U.S. Southern Great Plains: A Comparison on Local Convective Regimes between ARM Observations, Reanalysis, and Climate Model Simulations. J. Hydrometeor., 22, 463-481.

Tian, Y., Y. Zhang, S. A. Klein, C. Schumacher, 2021: Interpreting the diurnal cycle of clouds and precipitation in the ARM GoAmazon observations: Shallow to deep convection transition. J. Geophys. Res. Atmos., 126, e2020JD033766.

Tian, J., Y. Zhang, S. A. Klein, L. Wang, R. Ӧktem and D. M. Romps, 2021: Summertime continental shallow cumulus cloud detection using GOES-16 satellite and ground-based stereo cameras at the DOE ARM Southern Great Plains site. Remote Sens., 13, 2309.

Tao, C., Y. Zhang, S. Tang, Q. Tang, H.-Y. Ma, S. Xie, and M. Zhang, 2019: Regional moisture budget and land‐atmosphere coupling over the U.S. Southern Great Plains inferred from the ARM long‐term observations. J. Geophys. Res. Atmos., 124.

Lee, J., Y. Zhang, and S. A. Klein, 2019: The effect of land surface heterogeneity and background wind on shallow cumulus clouds and the transition to deeper convection. J. Atmos. Sci., 76, 401-419.

Terai, C. R., Y. Zhang, S. A. Klein, M. D. Zelinka, J. C. Chiu, and Q. Min, 2019: Mechanisms behind the extratropical stratiform low‐cloud optical depth response to temperature in ARM site observations, J. Geophys. Res. Atmos., 124, 2127– 2147.

Lareau, N. P., Y. Zhang, and S. A. Klein, 2018: Observed boundary layer controls on shallow cumulus at the ARM Southern Great Plains Site. J. Atmos. Sci., 75, 2235–2255,

Zhang, Y., S.A. Klein, J. Fan, A.S. Chandra, P. Kollias, S. Xie, and S. Tang, 2017: Large-Eddy Simulation of Shallow Cumulus over Land: A Composite Case Based on ARM Long-Term Observations at Its Southern Great Plains Site. J. Atmos. Sci., 74, 3229–3251,

Xie, S., Y. Zhang, S. Giangrande, M. Jensen, R. McCoy, and M. Zhang, 2014:  Interactions between Cumulus Convection and Its Environment as Revealed by the MC3E Sounding Array. J. Geophys. Res. Atmos.,

Zhang, Y. and S.A. Klein, 2013: Factors Controlling the Vertical Extent of Fair-Weather Shallow Cumulus Clouds over Land: Investigation of Diurnal-Cycle Observations Collected at the ARM Southern Great Plains Site. J. Atmos. Sci., 70, 1297–1315,

Caldwell, P., Y. Zhang and S. A. Klein, 2013: CMIP3 low cloud feedback interpreted through a mixed-layer model.  J. Climate 26, 1607-1625.

Zhang, Y. and S.A. Klein, 2010: Mechanisms Affecting the Transition from Shallow to Deep Convection over Land: Inferences from Observations of the Diurnal Cycle Collected at the ARM Southern Great Plains Site. J. Atmos. Sci., 67, 2943–2959,

Zhang, Y., B. Stevens, B. Medeiros, and M. Ghil, 2009: Low-Cloud Fraction, Lower-Tropospheric Stability, and Large-Scale Divergence. J. Climate, 22, 4827–4844,

Zhang, Y., S. A. Klein, C. Liu, B. Tian, R. T. Marchand, J. M. Haynes, R. B. McCoy, Y. Zhang, and T. P. Ackerman, 2008: On the diurnal cycle of deep convection, high-level cloud, and upper troposphere water vapor in the Multiscale Modeling Framework, J. Geophys. Res. Atmos., 113, D16105,

Zhang, Y., B. Stevens and M. Ghil, 2005: On the diurnal cycle and susceptibility to aerosol concentration in a stratocumulus-topped mixed layer. Quart. J. Roy. Meteor. Soc., 131, 1567–1583.

  • Early Career Research Program award, US Department of Energy, 2015
  • Spot Award, Atmospheric, Earth and Energy Division, PLS, LLNL, 2016, 2017, 2018
  • Chancellor Dissertation Fellowship, University of California, Los Angeles, 2005
  • Best Student Poster Award, American Meteorological Society the 16th Symposium on Boundary Layers and Turbulence, Portland, Maine, 2004
  • IGPP Fellowship, University of California, Los Angeles, 1999-2001
  • Chancellor Fellowship, University of California, Los Angeles, 1999


  • DOE Atmospheric System Research (ASR) Program, Co-Chair Warm Boundary Layer Processes Working Group,  the ARM-ASR Coordination Team (AACT) member, since 2017
  • DOE Atmospheric Radiation Measurement (ARM) Program, User Executive Committee member since 2021; Science Board member since 2020
  • Member of the GEWEX Global Land/Atmosphere System Study (GLASS) Panel and GEWEX Data and Analysis Panel (GDAP) since 2021; member of the GLASS Local Land-Atmosphere Coupling (LoCo) working group since 2016
  • Organizing committee member, “The future of the atmospheric large eddy simulation”, the DOE ASR LES workshop, 2022; “Improving understanding of land atmosphere interactions through integration of surface flux and atmospheric boundary layer measurements”, the AmeriFlux Land-Atmosphere Interaction workshop in collaboration with the DOE ASR and ARM programs, 2021; “Improvement and Calibration of Clouds in Models”, Toulouse, France, 2021; “Understanding and Modeling Atmospheric Processes (UMAP)”, 2nd PAN-GASS meeting, Australia, 2018
  • LLNL Laboratory Directed Research and Development (LDRD), Energy, Earth, and Atmospheric S&T committee, 2017 to 2019
  • Proposal or panel reviewer for DOE, NASA, NSF, NOAA, Israel Science Foundation and Netherlands Organization of Scientific Research, and peer reviewers for 17 scientific journals
  • Associate editor, Journal of Geophysical Research - Atmospheres since 2022
  • Mentor to 5 postdocs in recent years