Sciences and Exploration Directorate

Florian Tornow

(Post Doc)


Org Code: 611

Mail Code: 611
New York, NY 10025


Research Interests

Clouds and Satellite-based Estimates of their Albedo

Earth Science: Solar Radiation

Clouds reflect large portions of incoming sunlight back to space. To quantify this portion (termed cloud albedo) satellite-borne radiometry of Earth’s atmosphere is essential. Since clouds reflect sunlight unevenly into different space-facing directions and a satellite is only able to capture one of these directions at a time, assumptions are necessary of much reflected radiation went into all unobserved directions. So called angular distribution models rely on past satellite observations to statistically capture reflection patterns for different cloud properties and states of Earth’s surface. In my recent work (Tornow et al., 2020) I developed a novel semi-statistical angular distribution model that incorporates additional cloud microphysical and atmospheric properties and that may improve determining clouds’ albedo from satellite (Tornow et al., 2021a).

Cloud Microphysical Processes

Earth Science: Aerosols & Clouds

The life of clouds is in large parts determined at the smallest scales. In my current work, I’m using large-eddy simulations to investigate how clouds, which form during marine cold air outbreaks, evolve as they interact with aerosols from within the boundary layer as well as the free troposphere that contributes through entrainment. In our latest work, we assess the role of frozen hydrometeors to accelerate the cloud transition from overcast to broken state (Tornow et al., 2021b).

Current Projects

ACTIVATE (Aerosol Cloud Meteorology Interactions Over the Western Atlantic Experiment), funded by NASA’s Science Mission Directorate through the Earth Venture Suborbital Program

Aerosols and Clouds

We aim to improve our understanding of cloud-aerosol interaction through the use of in-situ and remote sensing data gathered from two aircrafts as well as numeric simulations. In my work, I use large-eddy simulations to study the evolution of clouds in cold air outbreaks and the role of microphysical processes in them.


Post-doctoral research scientist

Columbia University, Columbia University Center for Climate System Research and NASA GISS - New York, NY

December 2019 - Present

Research Assistant

Institute for Space Sciences, Freie Universität Berlin - Berlin, Germany

September 2014 - November 2019


Royal Meteorological Institute of Belgium - Brussels, Belgium

May 2014 - August 2014

Student Assistant

Institute for Space Sciences, Freie Universität Berlin - Berlin, Germany

February 2012 - February 2014


2018    PhD, Freie Universität Berlin, Berlin, Germany, Thesis: “Contributions to Estimating Top-Of-Atmosphere Radiative Fluxes using EarthCARE’s BroadBand Radiometer” (Magna cum laude), Advisor: Prof. Dr. Jürgen Fischer

2014.   M. Sc., Freie Universität Berlin, Berlin, Germany, Thesis: “Analysis of radiance co-registration methods for the multi-angular BBR in the framework of the EarthCARE mission”, Advisor: Prof. Dr. Jürgen Fischer




Tornow, F., A. S. Ackerman, A. M. Fridlind, et al. G. Tselioudis, B. Cairns, D. Painemal, and G. Elsaesser. 2023. On the impact of a dry intrusion driving cloud-regime transitions in a midlatitude cold-air outbreak Journal of the Atmospheric Sciences [10.1175/jas-d-23-0040.1]

Painemal, D., S. Chellappan, W. L. Smith, et al. D. Spangenberg, J. M. Park, A. Ackerman, J. Chen, E. Crosbie, R. Ferrare, J. Hair, S. Kirschler, X. Li, A. McComiskey, R. H. Moore, K. Sanchez, A. Sorooshian, F. Tornow, C. Voigt, H. Wang, E. Winstead, X. Zeng, L. Ziemba, and P. Zuidema. 2023. Wintertime synoptic patterns of midlatitude boundary layer clouds over the western North Atlantic: Climatology and insights from in‐situ ACTIVATE observations Journal of Geophysical Research: Atmospheres [10.1029/2022jd037725]

Li, X.-Y., H. Wang, J. Chen, et al. S. Endo, S. Kirschler, C. Voigt, E. Crosbie, L. D. Ziemba, D. Painemal, B. Cairns, J. W. Hair, A. F. Corral, C. Robinson, H. Dadashazar, A. Sorooshian, G. Chen, R. A. Ferrare, M. M. Kleb, H. Liu, R. Moore, A. J. Scarino, M. A. Shook, T. J. Shingler, K. L. Thornhill, F. Tornow, H. Xiao, and X. Zeng. 2023. Large-Eddy Simulations of Marine Boundary Layer Clouds Associated with Cold-Air Outbreaks during the ACTIVATE Campaign. Part II: Aerosol–Meteorology–Cloud Interaction Journal of the Atmospheric Sciences 80 (4): 1025-1045 [10.1175/jas-d-21-0324.1]

Tornow, F., A. S. Ackerman, A. M. Fridlind, et al. B. Cairns, E. C. Crosbie, S. Kirschler, R. H. Moore, D. Painemal, C. E. Robinson, C. Seethala, M. A. Shook, C. Voigt, E. L. Winstead, L. D. Ziemba, P. Zuidema, and A. Sorooshian. 2022. Dilution of Boundary Layer Cloud Condensation Nucleus Concentrations by Free Tropospheric Entrainment During Marine Cold Air Outbreaks Geophysical Research Letters 49 (11): [10.1029/2022gl098444]

Seethala, C., P. Zuidema, J. Edson, et al. M. Brunke, G. Chen, X. Li, D. Painemal, C. Robinson, T. Shingler, M. Shook, A. Sorooshian, L. Thornhill, F. Tornow, H. Wang, X. Zeng, and L. Ziemba. 2021. On Assessing ERA5 and MERRA2 Representations of Cold‐Air Outbreaks Across the Gulf Stream Geophysical Research Letters 48 (19): [10.1029/2021gl094364]

Tornow, F., A. S. Ackerman, and A. M. Fridlind. 2021. Preconditioning of overcast-to-broken cloud transitions by riming in marine cold air outbreaks Atmospheric Chemistry and Physics 21 (15): 12049-12067 [10.5194/acp-21-12049-2021]

Gristey, J. J., W. Su, N. G. Loeb, et al. T. H. Vonder Haar, F. Tornow, K. S. Schmidt, M. Z. Hakuba, P. Pilewskie, and J. E. Russell. 2021. Shortwave Radiance to Irradiance Conversion for Earth Radiation Budget Satellite Observations: A Review Remote Sensing 13 (13): 2640 [10.3390/rs13132640]

Tornow, F., C. Domenech, J. N. Cole, N. Madenach, and J. Fischer. 2021. Changes in TOA SW Fluxes over Marine Clouds When Estimated via Semi-Physical Angular Distribution Models Journal of Atmospheric and Oceanic Technology [10.1175/jtech-d-20-0107.1]

Tornow, F., C. Domenech, H. W. Barker, R. Preusker, and J. Fischer. 2020. Using two-stream theory to capture fluctuations of satellite-perceived TOA SW radiances reflected from clouds over ocean Atmospheric Measurement Techniques 13 (7): 3909-3922 [10.5194/amt-13-3909-2020]

Tornow, F., C. Domenech, and J. Fischer. 2019. On the Use of Geophysical Parameters for the Top-of-Atmosphere Shortwave Clear-Sky Radiance-to-Flux Conversion in EarthCARE Journal of Atmospheric and Oceanic Technology 36 (4): 717-732 [10.1175/jtech-d-18-0087.1]

Tornow, F., H. W. Barker, V. Blázquez, C. Domenech, and J. Fischer. 2018. EarthCARE’s Broadband Radiometer: Uncertainties Associated with Cloudy Atmospheres Journal of Atmospheric and Oceanic Technology 35 (11): 2201-2211 [10.1175/jtech-d-18-0083.1]

Tornow, F., R. Preusker, C. Domenech, et al. C. Carbajal Henken, S. Testorp, and J. Fischer. 2018. Top-of-Atmosphere Shortwave Anisotropy over Liquid Clouds: Sensitivity to Clouds’ Microphysical Structure and Cloud-Topped Moisture Atmosphere 9 (7): 256 [10.3390/atmos9070256]

Tornow, F., N. Clerbaux, A. Ipe, and M. Urbain. 2017. An improved method to estimate reference cloud-free images for the visible band of geostationary satellites International Journal of Remote Sensing 38 (23): 7220-7241 [10.1080/01431161.2017.1372859]

Tornow, F., H. W. Barker, and C. Domenech. 2015. On the use of simulated photon paths to co‐register top‐of‐atmosphere radiances in EarthCARE radiative closure experiments Quarterly Journal of the Royal Meteorological Society 141 (693): 3239-3251 [10.1002/qj.2606]