Getting to Grips with Clouds

25 Oct 2019

Postdoc Linda Forster is an Outgoing LMU Research Fellow and is now engaged on a project on cloud formation at the California Institute of Technology (Caltech). The results should help to improve forecasts of future climate change.

It is usually assumed that someone whose head is in the clouds doesn’t really deserve to be taken seriously. But that postulate certainly does not apply to physicist Linda Forster. Clouds are her daily bread-and-butter, so to speak. “Despite clouds being an everyday phenomenon, we still have to learn a great deal about their properties. Acting both as reflectors and absorbers, they have a huge impact on the radiation budget of the of the atmosphere, and thus on climate.”

In November 2018, Forster left Munich for Pasadena in Los Angeles County with an LMU Research Fellowship in her pocket. She now works at Jet Propulsion Laboratory (JPL) operated by Caltech. Roughly 9600 km separate the JPL from her birthplace in the administrative district of Wolfratshausen in Bavaria. But she had long hoped to have the chance to do research at JPL, where NASA develops its satellites and directs their voyages in space. So her own long journey to California was a dream come true. More than rainfall and sunshine

While most people only talk about the weather, Forster has always been more interested in the whys and the hows of what goes on in the atmosphere. “At school, I had a distinct preference for natural sciences and for tinkering around with things,” she recalls. So it’s perhaps not surprising that her research has a markedly practical bent. Her doctoral research at LMU was devoted to the development of a camera system (HaloCam) to study halo displays formed by ice clouds as well as a method that allowed her to retrieve shape, size and concentration of the ice crystals inside the clouds from the recorded photos. For this work, she received an Amelia Earhart International Fellowship.

The goal of my current project is to create 3D reconstructions of cloud volumes based on high-resolution satellite images taken from multiple viewing angles,” she says. “I hope that this will lead to a better understanding of the properties of clouds, and tell us more about how they develop.” Conventional satellite-based forms of remote sensing actually provide very little information about the inner structure of clouds. But Forster points out that vertical cloud profiles in particular could yield important insights into the formation and development of clouds. This type of data could potentially close gaps in our knowledge which contribute to the uncertainties that remain in state-of-the-art climate models.

A more detailed picture of the three-dimensional composition of clouds would allow climatologists to improve their estimates of the extent to which clouds absorb and reflect solar radiation. This in turn would enhance the accuracy of forecasts of future climate change. In the first phase of her current project, Forster is working primarily with computer simulations. “I spend most of my time at the computer, so I’m not in the lab as much as I used to be. But the development of new methods with the aid of JPL’s supercomputer and the analysis of satellite data are just as exciting!” 2.200 Students – 38 Nobel Laureates

At Caltech, Forster has access to the best technical infrastructure in the world for her purpose. But that’s not all. No less than 38 Nobel Laureates either studied or carried out research there. Caltech is a comparatively small university with only 2200 students, but it is regularly ranked among the ten best third-level institutions in the world. Furthermore, she can count on continuing support from her alma mater. Although she is now based virtually on the shores of the Pacific, she maintains regular contact with her mentor and former doctoral supervisor Professor Bernhard Mayer at LMU’s Meteorological Institute der LMU.

Linda Forster works where NASA develops many of their satelites: The Jet Propulsion Laboratory at Caltech. (Photo: Linda Forster)

The fact that Forster can call upon the expertise of three institutions is one of the advantages enjoyed by holders of an Outgoing LMU Research Fellowship. The scheme was initiated in 2017, and each year it enables five highly promising junior researchers to carry out a research project of their own choosing at a non-European university. “It’s an amazing opportunity for a young researcher to have – the chance to choose a research project and the best possible host institution for its realization,” she says. In addition, Fellows are in an ideal position to learn new techniques and make useful contacts. – Forster recently met Katie Bouman, who made a major contribution to the recent imaging of the vicinity of the black hole at the center of the galaxy M87, and the two are planning to collaborate in the near future. There and back again

Forster has adapted well to her new environment. Anthony Davis, her sponsor at JPL, and Yuk Yung, her supporting professor at Caltech, each gave her a warm welcome and helped her to find her feet. Settling in was greatly facilitated by the fact that Caltech provides apartments in the immediate vicinity of the campus for new postdocs. Her working day begins at around 9 in the morning and usually ends as darkness falls. This leaves her with little time to enjoy the fabled Californian sunshine. But as compensation for the overtime she puts in, she can take a long weekend off every fortnight, which gives her a chance to enjoy beach volleyball or surfing. “I was able to practice on the Eisbachwelle on the Isar in Munich before I arrived,” she remarks.

Linda Forster’s stay in California is now nearing its end, and she will soon return to LMU for the second half of her Fellowship. Although she regrets having to leave the US, she is nevertheless looking forward to coming back to her alma mater. “The great thing about an LMU Research Fellowship,” she says, “is that in the outgoing phase one gains experience and can make new contacts, while retaining one’s links with one’s research group at LMU.”

The deadline for applications for LMU Research Fellowships is November 12, 2019. Further information on the program and how to apply is available here. You may also be interested in this:

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