Katja Friedrich, ATOC Professor

Though precipitation and evaporation are ubiquitous phenomena across the globe, they are infamously difficult to measure and forecast. Dr. Katja Friedrich, Atmospheric and Oceanic Sciences (ATOC) Professor, is investigating the microphysics of clouds and precipitation, with specific attention to snowstorms, thunderstorms, and floods in mountainous and alpine regions. Her latest research focuses on measuring and forecasting evaporation from reservoirs in Colorado. She explains:


“My research team is trying to determine better means of measuring and forecasting precipitation in particular during hazardous high-impact events such as snowstorms, thunderstorms, and floods. Lately, we also focus on the lack of water during drought events, the conservation of water through minimizing evaporation, and extracting water from clouds through cloud seeding. With drought settling into many areas in the western United States, the need to conserve water, and [thus to] understand these systems, is of [imminent] importance.”

Katja Friedrich’s interest in precipitation microphysics can be traced to her Ph.D. studies:

“My background is in atmospheric science. During my Ph.D. work in Munich, Germany, I worked with a bistatic radar – a very new instrument that was developed to observe simultaneously wind and precipitation.  This work, which involved studying thunderstorm and snowstorm structures in the Alps, sparked my interest in microphysics and severe weather.”

Joining the ATOC faculty in 2008, Friedrich spearheads the Cloud and Precipitaiton Research Group. Her research stimulates significant collaborations among researchers both internally and externally to the CU atmospheric community.

In an effort to improve understanding of evaporation processes for enhancement of Colorado’s water management, Friedrich has undertaken the "Reservoir Evaporation Project". She explains:


Mobile radar deployed during a cloud seeding experiment led by Friedrich. Credit: Katja Friedrich.

“The State of Colorado is currently developing a plan to meet future growing water demands. Reservoir evaporation has been perceived as a negligible component of the water cycle within the water resource infrastructure of the arid and semi-arid western United States. This is partly due to both practical and logistical challenges and large uncertainties in its estimation. Reservoirs act as critical buffers to meet agricultural and municipal water deliveries, mitigate flooding, and for hydroelectric power production...

We decided that CU, [involving collaborations between the ATOC Department, Geography Department and the Cooperative Institute for Research in Environmental Sciences], should take the lead bringing together recognized experts in the field of atmospheric science, hydrology, land use, and water resource managers. We are trying to determine what can we do to monitor and forecast reservoir evaporation, and what we can do to implement that into an operational set-up.”

In addition, Friedrich is investigating methods of extracting more water out of clouds, a process known as “cloud seeding.” She notes:

“Research has been going on in the field of cloud seeding for the past 50 to 60 years. In a lab setting, cloud seeding, [a form of weather modification], works; however, in nature, we are having difficulty [showing its viability].”

Friedrich is teaming with scientists from the University of Wyoming and the Boulder-based National Center for Atmospheric Research (NCAR) to conduct cloud seeding research in Wyoming. Due to improvements in instrumentation, Friedrich explains that researchers are able to “extract the few millimeters of additional water that seeding can provide.”


A Cloud and Precipitation Research Group student recovering a precipitation instrument from the snow at the CU Mountain Research Station at Niwot. Credit: Katja Friedrich.

Friedrich’s research has been greatly enhanced by the utilization of unmanned areal vehicles (UAVs). She explains:

“I worked with the AES department on VORTEX2 (2009-2010). During that project, I got very keen on UAVs. Unlike radiosondes, which only give us a vertical profile of temperature, wind, and humidity, UAVs allow us to measure make atmospheric measurements continuously in 3D space. The RECUV (Research and Engineering Center for Unmanned Vehicles) recently received permission to fly in the mountains between Boulder and Nederland. I will be collaborating with RECUV on this project to try and understand how and where clouds form.”

Along with her research, Friedrich has placed a special emphasis on promoting undergraduate education. She aided in the formation of the ATOC Skywatch Observatory, a weather laboratory with the mission of introducing undergraduate students to atmospheric sciences. Friedrich discusses the motivation underlying ATOC’s formation:

“When I came to CU in 2008, we wanted to go beyond teaching students how to conduct temperature and pressure measurements and introduce undergraduate students to more complex instruments. Prof. Pilewskie and I received an NSF-grant and purchased more sophisticated instruments to create the ATOC Skywatch Observatory; we then developed exercises and homework assignments to familiarize students with the limitations, strengths and weaknesses of instruments and data.”

Despite the international nature of atmospheric science research, Friedrich, a German-native, notes the value of being Boulder-based:

“Boulder is a great place to collaborate with scientists from various research areas at institutions like NCAR and NOAA; the university itself, with its departments and centers [such as] INSTARR, LASP, and CIRES, has a wealth of researchers investigating atmospheric sciences even outside of ATOC. Interacting with these scientists leads to many new research ideas and approaches. I find Boulder a very inspirational place.”

-Written By: Ari Sandberg, Intern