Gerrit Holl
Wissenschaftlicher Mitarbeiter at Deutscher Wetterdienst
Offenbach am Main, Hesse, Germany
Summary
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Top SchoolGerrit Holl is a Wissenschaftlicher Mitarbeiter with 12 years of experience developing satellite-based nowcasting and operational imagery products at the Deutscher Wetterdienst, combining research and production responsibilities. He holds a strong academic background in space science and applied physics, with postdoctoral work on atmospheric retrievals and contributions to international projects such as FIDUCEO. Gerrit brings practical software engineering and QA expertise to scientific Python ecosystems, contributing bug fixes, tests, and documentation to flagship projects like xarray and NumPy and improving fsspec’s caching tests. His work shows attention to numerical edge cases, data-handling subtleties (NetCDF/h5netcdf), and reproducible testing—skills that bridge atmospheric science and robust data software. Based in Offenbach am Main, he is focused on preparing meteorological services for next-generation geostationary satellites while keeping one foot in open-source code quality and reliability.
12 years of coding experience
4 years of employment as a software developer
Bachelor of Science (B.Sc.), Applied Physics, Bachelor of Science (B.Sc.), Applied Physics at University of TwenteMaster of Science (M.Sc.), Space Science and Technology, Master of Science (M.Sc.), Space Science and Technology at Luleå University of Technology
English, Dutch
Stackoverflow
25,126reputation
6.5mreached
102answers
163questions
python-decorators
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asynchronous
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python
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passwords
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numpy
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subprocess
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Github Skills (25)
pytest10
python10
python-decorators10
testing10
xray10
numpy10
fsspec10
passwords10
xa10
abstract-class10
netcdf10
test-automation10
data-structure9
asynchronous9
subprocess9
Programming languages (13)
Github contributions (5)
pydata/xarray
Jan 2017 - Oct 2020
N-D labeled arrays and datasets in Python
Role in this project:
Back-end Developer
Back-end DeveloperContributions:2 reviews, 5 commits, 8 PRs in 3 years 9 months
Contributions summary:Gerrit primarily contributed to bug fixes and documentation improvements within the xarray library. Their work included correcting error messages, addressing issues related to floating-point data types, and ensuring compliance with PEP 440 for versioning. Furthermore, the user improved the handling of scalar attributes when reading NetCDF files with the h5netcdf engine, adding a test and updating documentation to reflect the change. They demonstrate a good understanding of the xarray codebase and focus on data handling details.
pythonnetcdfnumpydaskarrays
numpy/numpy
Jan 2015 - Jan 2018
The fundamental package for scientific computing with Python.
Role in this project:QA Engineer / Test Automation Engineer
QA Engineer / Test Automation EngineerContributions:14 commits, 13 PRs, 84 comments in 3 years
Contributions summary:Gerrit primarily contributed to improving the quality and reliability of the NumPy library. They focused on adding and modifying test cases to address specific bugs and edge cases, specifically related to masked arrays and structured data types. These contributions included ensuring correct behavior of masked_where and fill values, and ensuring consistent handling of zero-dimensional arrays, ultimately enhancing the robustness of the library. Their work directly addressed reported issues, ensuring the integrity of NumPy's core functionalities.
lapackpythonmpindarrayconvolution
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