TY  - JOUR
A1  - Grott, Matthias
A1  - Knollenberg, J.
A1  - Hamm, M.
A1  - Ogawa, K.
A1  - Jaumann, R.
A1  - Otto, Katharina Alexandra
A1  - Delbo, M.
A1  - Michel, P.
A1  - Biele, J.
A1  - Neumann, W.
A1  - Knapmeyer, M.
A1  - Kuehrt, E.
A1  - Senshu, H.
A1  - Okada, T.
A1  - Helbert, J.
A1  - Maturilli, A.
A1  - Müller, N.
A1  - Hagermann, A.
A1  - Sakatani, N.
A1  - Tanaka, S.
A1  - Arai, T.
A1  - Mottola, S.
A1  - Tachibana, S.
A1  - Pelivan, Ivanka
A1  - Drube, L.
A1  - Vincent, J-B
A1  - Yano, H.
A1  - Pilorget, C.
A1  - Matz, K. D.
A1  - Schmitz, N.
A1  - Koncz, A.
A1  - Schröder, S. E.
A1  - Trauthan, F.
A1  - Schlotterer, M.
A1  - Krause, C.
A1  - Ho, T-M
A1  - Moussi-Soffys, A.
T1  - Low thermal conductivity boulder with high porosity identified on C-type asteroid (162173) Ryugu
JF  - Nature astronomy
N2  - C-type asteroids are among the most pristine objects in the Solar System, but little is known about their interior structure and surface properties. Telescopic thermal infrared observations have so far been interpreted in terms of a regolith-covered surface with low thermal conductivity and particle sizes in the centimetre range. This includes observations of C-type asteroid (162173) Ryugu1,2,3. However, on arrival of the Hayabusa2 spacecraft at Ryugu, a regolith cover of sand- to pebble-sized particles was found to be absent4,5 (R.J. et al., manuscript in preparation). Rather, the surface is largely covered by cobbles and boulders, seemingly incompatible with the remote-sensing infrared observations. Here we report on in situ thermal infrared observations of a boulder on the C-type asteroid Ryugu. We found that the boulder’s thermal inertia was much lower than anticipated based on laboratory measurements of meteorites, and that a surface covered by such low-conductivity boulders would be consistent with remote-sensing observations. Our results furthermore indicate high boulder porosities as well as a low tensile strength in the few hundred kilopascal range. The predicted low tensile strength confirms the suspected observational bias6 in our meteorite collections, as such asteroidal material would be too frail to survive atmospheric entry7.
Y1  - 2020
U6  - https://doi.org/10.1038/s41550-019-0832-x
SN  - 2397-3366
VL  - 3
IS  - 11
SP  - 971
EP  - 976
PB  - Nature Publishing Group
CY  - London
ER  - 
TY  - JOUR
A1  - Grott, Matthias
A1  - Knollenberg, J.
A1  - Hamm, M.
A1  - Ogawa, K.
A1  - Jaumann, R.
A1  - Otto, Katharina Alexandra
A1  - Delbo, M.
A1  - Michel, Patrick
A1  - Biele, J.
A1  - Neumann, Wladimir
A1  - Knapmeyer, Martin
A1  - Kührt, E.
A1  - Senshu, H.
A1  - Okada, T.
A1  - Helbert, Jorn
A1  - Maturilli, A.
A1  - Müller, N.
A1  - Hagermann, A.
A1  - Sakatani, Naoya
A1  - Tanaka, S.
A1  - Arai, T.
A1  - Mottola, Stefano
A1  - Tachibana, Shogo
A1  - Pelivan, Ivanka
A1  - Drube, Line
A1  - Vincent, J-B
A1  - Yano, Hajime
A1  - Pilorget, C.
A1  - Matz, K. D.
A1  - Schmitz, N.
A1  - Koncz, A.
A1  - Schröder, Stefan E.
A1  - Trauthan, F.
A1  - Schlotterer, Markus
A1  - Krause, C.
A1  - Ho, T-M
A1  - Moussi-Soffys, A.
T1  - Low thermal conductivity boulder with high porosity identified on C-type asteroid (162173) Ryugu
JF  - Nature astronomy
N2  - C-type asteroids are among the most pristine objects in the Solar System, but little is known about their interior structure and surface properties. Telescopic thermal infrared observations have so far been interpreted in terms of a regolith-covered surface with low thermal conductivity and particle sizes in the centimetre range. This includes observations of C-type asteroid (162173) Ryugu1,2,3. However, on arrival of the Hayabusa2 spacecraft at Ryugu, a regolith cover of sand- to pebble-sized particles was found to be absent4,5 (R.J. et al., manuscript in preparation). Rather, the surface is largely covered by cobbles and boulders, seemingly incompatible with the remote-sensing infrared observations. Here we report on in situ thermal infrared observations of a boulder on the C-type asteroid Ryugu. We found that the boulder’s thermal inertia was much lower than anticipated based on laboratory measurements of meteorites, and that a surface covered by such low-conductivity boulders would be consistent with remote-sensing observations. Our results furthermore indicate high boulder porosities as well as a low tensile strength in the few hundred kilopascal range. The predicted low tensile strength confirms the suspected observational bias6 in our meteorite collections, as such asteroidal material would be too frail to survive atmospheric entry7
Y1  - 2019
U6  - https://doi.org/10.1038/s41550-019-0832-x
SN  - 2397-3366
VL  - 3
IS  - 11
SP  - 971
EP  - 976
PB  - Nature Publishing Group
CY  - London
ER  - 
TY  - GEN
A1  - Frieler, Katja
A1  - Levermann, Anders
A1  - Elliott, J.
A1  - Heinke, J.
A1  - Arneth, A.
A1  - Bierkens, M. F. P.
A1  - Ciais, Philippe
A1  - Clark, D. B.
A1  - Deryng, D.
A1  - Doell, P.
A1  - Falloon, P.
A1  - Fekete, B.
A1  - Folberth, Christian
A1  - Friend, A. D.
A1  - Gellhorn, C.
A1  - Gosling, S. N.
A1  - Haddeland, I.
A1  - Khabarov, N.
A1  - Lomas, M.
A1  - Masaki, Y.
A1  - Nishina, K.
A1  - Neumann, K.
A1  - Oki, T.
A1  - Pavlick, R.
A1  - Ruane, A. C.
A1  - Schmid, E.
A1  - Schmitz, C.
A1  - Stacke, T.
A1  - Stehfest, E.
A1  - Tang, Q.
A1  - Wisser, D.
A1  - Huber, V.
A1  - Piontek, Franziska
A1  - Warszawski, L.
A1  - Schewe, Jacob
A1  - Lotze-Campen, Hermann
A1  - Schellnhuber, Hans Joachim
T1  - A framework for the cross-sectoral integration of multi-model impact projections
BT  - land use decisions under climate impacts uncertainties
T2  - Earth system dynamics
N2  - Climate change and its impacts already pose considerable challenges for societies that will further increase with global warming (IPCC, 2014a, b). Uncertainties of the climatic response to greenhouse gas emissions include the potential passing of large-scale tipping points (e.g. Lenton et al., 2008; Levermann et al., 2012; Schellnhuber, 2010) and changes in extreme meteorological events (Field et al., 2012) with complex impacts on societies (Hallegatte et al., 2013). Thus climate change mitigation is considered a necessary societal response for avoiding uncontrollable impacts (Conference of the Parties, 2010). On the other hand, large-scale climate change mitigation itself implies fundamental changes in, for example, the global energy system. The associated challenges come on top of others that derive from equally important ethical imperatives like the fulfilment of increasing food demand that may draw on the same resources. For example, ensuring food security for a growing population may require an expansion of cropland, thereby reducing natural carbon sinks or the area available for bio-energy production. So far, available studies addressing this problem have relied on individual impact models, ignoring uncertainty in crop model and biome model projections. Here, we propose a probabilistic decision framework that allows for an evaluation of agricultural management and mitigation options in a multi-impact-model setting. Based on simulations generated within the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP), we outline how cross-sectorally consistent multi-model impact simulations could be used to generate the information required for robust decision making.

Using an illustrative future land use pattern, we discuss the trade-off between potential gains in crop production and associated losses in natural carbon sinks in the new multiple crop-and biome-model setting. In addition, crop and water model simulations are combined to explore irrigation increases as one possible measure of agricultural intensification that could limit the expansion of cropland required in response to climate change and growing food demand. This example shows that current impact model uncertainties pose an important challenge to long-term mitigation planning and must not be ignored in long-term strategic decision making.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 457 
KW  - global food demand
KW  - water availability
KW  - elevated CO2
KW  - future
KW  - carbon
KW  - system
KW  - productivity
KW  - agriculture
KW  - emissions
KW  - scarcity
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-407968
ER  - 
TY  - JOUR
A1  - Frieler, Katja
A1  - Levermann, Anders
A1  - Elliott, J.
A1  - Heinke, Jens
A1  - Arneth, A.
A1  - Bierkens, M. F. P.
A1  - Ciais, Philippe
A1  - Clark, D. B.
A1  - Deryng, D.
A1  - Doell, P.
A1  - Falloon, P.
A1  - Fekete, B.
A1  - Folberth, Christian
A1  - Friend, A. D.
A1  - Gellhorn, C.
A1  - Gosling, S. N.
A1  - Haddeland, I.
A1  - Khabarov, N.
A1  - Lomas, M.
A1  - Masaki, Y.
A1  - Nishina, K.
A1  - Neumann, K.
A1  - Oki, T.
A1  - Pavlick, R.
A1  - Ruane, A. C.
A1  - Schmid, E.
A1  - Schmitz, C.
A1  - Stacke, T.
A1  - Stehfest, E.
A1  - Tang, Q.
A1  - Wisser, D.
A1  - Huber, Veronika
A1  - Piontek, Franziska
A1  - Warszawski, Lila
A1  - Schewe, Jacob
A1  - Lotze-Campen, Hermann
A1  - Schellnhuber, Hans Joachim
T1  - A framework for the cross-sectoral integration of multi-model impact projections
BT  - land use decisions under climate impacts uncertainties
JF  - Earth system dynamics
N2  - Climate change and its impacts already pose considerable challenges for societies that will further increase with global warming (IPCC, 2014a, b). Uncertainties of the climatic response to greenhouse gas emissions include the potential passing of large-scale tipping points (e.g. Lenton et al., 2008; Levermann et al., 2012; Schellnhuber, 2010) and changes in extreme meteorological events (Field et al., 2012) with complex impacts on societies (Hallegatte et al., 2013). Thus climate change mitigation is considered a necessary societal response for avoiding uncontrollable impacts (Conference of the Parties, 2010). On the other hand, large-scale climate change mitigation itself implies fundamental changes in, for example, the global energy system. The associated challenges come on top of others that derive from equally important ethical imperatives like the fulfilment of increasing food demand that may draw on the same resources. For example, ensuring food security for a growing population may require an expansion of cropland, thereby reducing natural carbon sinks or the area available for bio-energy production. So far, available studies addressing this problem have relied on individual impact models, ignoring uncertainty in crop model and biome model projections. Here, we propose a probabilistic decision framework that allows for an evaluation of agricultural management and mitigation options in a multi-impact-model setting. Based on simulations generated within the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP), we outline how cross-sectorally consistent multi-model impact simulations could be used to generate the information required for robust decision making.
 Using an illustrative future land use pattern, we discuss the trade-off between potential gains in crop production and associated losses in natural carbon sinks in the new multiple crop-and biome-model setting. In addition, crop and water model simulations are combined to explore irrigation increases as one possible measure of agricultural intensification that could limit the expansion of cropland required in response to climate change and growing food demand. This example shows that current impact model uncertainties pose an important challenge to long-term mitigation planning and must not be ignored in long-term strategic decision making.
Y1  - 2015
U6  - https://doi.org/10.5194/esd-6-447-2015
SN  - 2190-4979
SN  - 2190-4987
VL  - 6
IS  - 2
SP  - 447
EP  - 460
PB  - Copernicus
CY  - Göttingen
ER  -