Can we infer rainfall sensitivity to global warming using observations of precipitation and temperature? Not quite, until you correct for the cooling effects of clouds.

Rainfall events are expected to become heavier as the hydrologic cycle intensifies with global warming. To determine this strengthening, many studies use observed precipitation events and test how these change with observed temperatures. These so-called scaling rates differ from what is expected from theory, showing a decline above temperatures of around 23° – 25°C. This breakdown in scaling makes it difficult to interpret the precipitation response to global warming and its cause further remains unclear. It also raises the question of whether a high-temperature threshold limits the increase in the intensity of precipitation events with temperature. We resolve this in our latest paper by showing that the break in scaling primarily occurs due to radiative effect of clouds on surface temperatures that leads to a covariation between the two variables.

Continue reading “Can we infer rainfall sensitivity to global warming using observations of precipitation and temperature? Not quite, until you correct for the cooling effects of clouds.”
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How much does evaporation affect temperature variations during the day?  That’s what we looked at in a paper just published online in the Journal of Climate.  @annuPanwar_sci @ametsoc @MPI_BGC

Over land, there is a marked variation in surface and air temperature during day and night, with the amplitude described by the diurnal temperature range.  What are the main factors that determine its magnitude across regions and how much is it shaped by evaporation?  This is what Annu Panwar looked at in her last part of her PhD using FluxNet observations and the ERA 5 reanalysis products, with the results just published online in the Journal of Climate. What this analysis shows is that energy balances go a long way to explain the main influences and that evaporation does not have quite such a strong effect as one may think.

Continue reading “How much does evaporation affect temperature variations during the day?  That’s what we looked at in a paper just published online in the Journal of Climate.  @annuPanwar_sci @ametsoc @MPI_BGC”

We’ll be at #EGU22, showing how radiation and maximum power shape temperatures, their extremes, the atmospheric circulation and the wind energy resource. @akleidon @s_ghausi @yinglin_tian

Corona is still around, also in Vienna, but the EGU General Assembly will nevertheless happen again, in a hybrid form. We are thrilled to be there physically, giving our 6 minute short talks on our work, and look forward to seeing and talking to you there!

Continue reading “We’ll be at #EGU22, showing how radiation and maximum power shape temperatures, their extremes, the atmospheric circulation and the wind energy resource. @akleidon @s_ghausi @yinglin_tian”

Interested in how the Earth system works?  I have a #PostDoc opening available in my group, applying thermodynamics, max. power, and optimality to Earth system science. @MPI_BGC

The position is in my research group, which focuses on how the Earth functions as a whole system, the role of life within it, and what a sustainable human future might look like. We take a unique Earth system approach that focuses on thermodynamics, energy conversions, and limits/optimality such as maximum power.

We are seeking a motivated and interested person to help us further develop this approach, evaluate it using observational data, and/or compare it to climate model results. More details are provided in the formal job announcement, which you can find here. More background information in this post.

Continue reading “Interested in how the Earth system works?  I have a #PostDoc opening available in my group, applying thermodynamics, max. power, and optimality to Earth system science. @MPI_BGC”

Last week our group member @annuPanwar_sci successfully defended her PhD thesis on diurnal temperature variations and how they are affected by evaporation and vegetation. Very well done, and congratulations, Annu! @mpibgc

Evaporation cools, right? What may sound so obvious was the topic of Annu’s PhD thesis: to look into observations and find the effects of evaporation in how surface and near-surface air temperatures vary throughout the day. The results are not quite as obvious, and we learned a lot. Here is a brief summary of her thesis, with its contents spread over three papers. Very nice work!

Continue reading “Last week our group member @annuPanwar_sci successfully defended her PhD thesis on diurnal temperature variations and how they are affected by evaporation and vegetation. Very well done, and congratulations, Annu! @mpibgc”

Can we solve the freshwater problem by taking moisture out of the atmosphere with dehumidifiers? When we look at how the hydrologic cycle does its work, we get a straight and clear answer: no, we don’t solve the problem!

In Germany, the construction of Tesla’s Gigafactory near Berlin draws its attention, including its substantial need for freshwater. Despite its many lakes, the area around Berlin is among the driest in Germany. The atmosphere contains water vapor, and it seems like a tempting source for freshwater, just sitting there to be harvested by some form of technology. This is what a company claims to do (and quite a few others elsewhere as well). But can this promise hold up?

Continue reading “Can we solve the freshwater problem by taking moisture out of the atmosphere with dehumidifiers? When we look at how the hydrologic cycle does its work, we get a straight and clear answer: no, we don’t solve the problem!”

“Kraftwerk Erde: Wie der belebte Planet Energie umwandelt” – Vortrag bei #FasziAstroOnline, heute Abend, 13.01.2022, 19 Uhr, live auf youtube.  Mehr Infos im Blog. @MPI_BGC @HdAstro

Die Erde arbeitet wie ein Kraftwerk, indem sie Sonnenenergie in andere Formen umwandelt, die die Winde der Atmosphäre, den Wasserkreislauf, und auch das Leben und die Menschheit auf der Erde erhalten.  Diese Umwandlungen folgen den Gesetzen der Thermodynamik, die sowohl die Richtung als auch die Grenzen setzt.  Aber Erdsystemprozesse beeinflussen sich auch gegenseitig, sodass man einen Blick auf das Gesamtsystem braucht.  In diesem Vortrag zeige ich, dass man allein durch diesen grundlegenden physikalischen Ansatz schon erstaunlich viel vom Erdsystem verstehen kann – über die fundamentalen Rolle von Energie und Entropie, wie Leben den Planeten verändert, aber auch zu angewandten Themen wie dem Klimawandel und warum die Photovoltaik die Technologie ist, die bei weitem den größten Beitrag zur Energiewende liefern wird.

Continue reading ““Kraftwerk Erde: Wie der belebte Planet Energie umwandelt” – Vortrag bei #FasziAstroOnline, heute Abend, 13.01.2022, 19 Uhr, live auf youtube.  Mehr Infos im Blog. @MPI_BGC @HdAstro”

At #AGU21, we present updates on understanding diurnal temperature variations on land and on deriving precipitation sensitivities from observations using “clear-sky” temperatures and maximum power

Corona has not yet gone away, but the AGU Fall Meeting nevertheless takes place, in a hybrid format. Annu Panwar will be physically there, giving an invited talk on her PhD thesis on diurnal temperature variations (see, e.g., her paper in HESS) and a poster, while Sarosh Alam Ghausi will be giving his poster on precipitation scaling virtually.

Continue reading “At #AGU21, we present updates on understanding diurnal temperature variations on land and on deriving precipitation sensitivities from observations using “clear-sky” temperatures and maximum power”

#vEMS21: Our updates on using #thermodynamics for land-atmosphere interactions, the precipitation response to #globalwarming, and the #windenergy potential in the German bight

With summer coming to a close, we are back to present new insights from ongoing research in extreme precipitation events, offshore wind energy and thermodynamics at the European Meteorological Society Annual Meeting 2021. The event, which will be held online next week (6 – 10 September 2021), focuses on weather and climate research and services for the achievement of the UN Sustainable Development Goals. Read on to find out more details about when and what each of us will be presenting.

Continue reading “#vEMS21: Our updates on using #thermodynamics for land-atmosphere interactions, the precipitation response to #globalwarming, and the #windenergy potential in the German bight”

#vEGU21 Next week we’ll present our work on precipitation scaling, diurnal temperature range, offshore wind, and limits to vegetation productivity based on our thermodynamic Earth system view

Thermodynamics rules the world, as well as the science that we present at this year’s EGU General Assembly, which is, alas, virtual rather than in Vienna. It may not be obvious, and our contributions are spread across different sessions. But in the end, we follow the solar energy as it passes through the Earth system, seeking simple, physics-based explanations to simple phenomena: precipitation scaling with temperature found in observations, the diurnal temperature range across regions and vegetation types, also in observations, limits to offshore wind energy in the North sea and what these imply for renewable energy scenarios, and how the really low efficiency of photosynthesis fits to the notion of vegetation being optimal.

Continue reading “#vEGU21 Next week we’ll present our work on precipitation scaling, diurnal temperature range, offshore wind, and limits to vegetation productivity based on our thermodynamic Earth system view”