Photosynthesis is the process which powers life on Earth. It takes the energy contained in sunlight, uses carbon dioxide, and generates chemical energy that is stored in form of sugars and similar compounds that fuel the activity of the biosphere, including us humans. And just as any other Earth system process, in doing so it follows the laws of thermodynamics. But does thermodynamics also restrict the efficiency by which photosynthesis can use sunlight?
I have an opening for a Postdoc position available in my group that is rather flexible and provides a lot of freedom because it is unattached to any research project (it is the succession of my co-worker Maik Renner, who advanced to a permanent position elsewhere). I would like the research to broadly focus on advancing the application of thermodynamics and optimality principles to Earth system science, but the concrete topic is up to you. So if you are curious to learn more about thermodynamics and how to apply it, I’d like you to think about a topic and apply! The formal details are provided on our homepage here. Continue reading “Are you looking for a stimulating Postdoc opportunity? Our group has a position open, applying thermodynamics and optimality to Earth system science.”
Global warming, the increase in near-surface temperature due to the enhanced greenhouse effect at global scale, has clearly been reflected in observations over the last 50 years. However, the severities of warming in different regions and different period differs a lot. Scientists have considered many factors which may contribute to shape the temperature trends. For example, our ESD paper explained the stronger temperature trends over land compared to oceans by the different ways by which the diurnal variation in solar radiation is buffered on land and ocean. Here we introduce another simple but significant factor, sunny and rainy days. Continue reading “Does global warming behave the same on rainy and sunny days? No, it doesn’t, and our new JGR paper explains why.”
Winds over the ocean typically have higher wind speeds, resulting in high efficiencies of wind turbines and making this an attractive environment for generating a lot of renewable energy. But how efficient are turbines going to be when offshore wind farms become larger and larger? Continue reading “More offshore wind energy is likely to reduce turbine efficiencies, but still a lot of renewable energy can be generated. This is what a new @AgoraEW study shows to which we contributed.”
Cutting down tropical rainforests and replacing them with soybean fields alters how the land surface functions, and this affects the atmosphere. Rainforests have a heterogeneous canopy that absorbs sunlight very well and is aerodynamically rough, and they have deep-reaching root systems that allow them to draw water from deep within the soil, especially during the dry season when water input by precipitation is limited. When trees are cut down and replaced by soybean fields, these physical aspects of the land surface are changed, thus impacting how the absorbed solar energy is partitioned at the surface, and how this energy is transferred into the overlying atmosphere. Tropical deforestation is one of the many aspects of global change that has been dealt with over the last decades, evaluated with observations and climate models, so what else can add new insights? And what can these insights be used for? Continue reading “Do roughness changes of tropical deforestation affect surface energy balance partitioning? No, they don’t. That’s what we found when we estimated the effects from first principles.”
In meteorology, air temperature measurements are typically taken 2m above the surface. It is a routine measurement at weather stations, and this temperature is the basis for analyzing trends, such as global warming. The temperature of the surface is not so often measured, but it can be inferred by satellites from how much radiation is being emitted by the surface. Being only 2m apart, one may think that the temperatures basically reflect more or less the same, given their close proximity. We actually found out that this is not the case: surface temperature responds much more strongly to a lack of water than air temperature. This finding was just published in our article in the journal Geophysical Research Letters. Continue reading “If you think surface and air temperature are basically the same thing, think again. Or read our new paper.”
I thought it might be a good idea to meet with wind energy critics to hear what they have to say. But my experience told me otherwise. Perhaps I should have been warned. They are associated with a German organization called „Vernunftkraft“, which has „sensible“ in its name. How presumptuous! It should have been a red warning flag for me. Continue reading “Making sense of German wind energy”
Why do I start writing a blog? Well, I see a few reasons: Continue reading “Starting a blog”