Archives par mot-clé : Model(s)

Pronounced differences between observed and CMIP5-simulated multidecadal climate variability in the twentieth century

by Sergey Kravtsov, June 15, 2017


The observed internal variability so estimated exhibits a pronounced multidecadal mode with a distinctive spatiotemporal signature, which is altogether absent in model simulations. This single mode explains a major fraction of model-data differences over the entire climate index network considered; it may reflect either biases in the models’ forced response or models’ lack of requisite internal dynamics, or a combination of both.

Climate Change: The Facts 2017

by Jennifer Marohasy, June3, 2017


Important new book coming out  …

Contributors to Climate Change: The Facts 2017 do not conform to a unitary view.   As I explain in the book’s introduction:

“An advantage of my approach in the compiling of the chapters for this book – an approach where there has been no real attempt to put everything into neat boxes – is that there are many surprises. I am referring to the snippets of apparently anomalous information scattered through the chapters. These can, hopefully, one day, be reconciled. As this occurs, we may begin to see the emergence of a coherent theory of climate – where output from computer-simulation models bears some resemblance to real-world measurements that have not first been ‘homogenised’.

 

 

80 Graphs From 58 New (2017) Papers Invalidate Claims Of Unprecedented Global-Scale Modern Warming

by Kenneth Richard, May 29, 2017


Last year there were at least 60 peer-reviewed papers published in scientific journals demonstrating that  Today’s Warming Isn’t Global, Unprecedented, Or Remarkable.
 .
Just within the last 5 months,  58 more papers and 80 new graphs have been published that continue to undermine the popularized conception of a slowly cooling Earth temperature history followed by a dramatic hockey-stick-shaped uptick, or an especially unusual global-scale warming during modern times.

 

Onset and ending of the late Palaeozoic ice age triggered by tectonically paced rock weathering

by Yves Goddéris et al., April 10, 2017, Nature Geoscience


The onset of the late Palaeozoic ice age about 340 million years ago has been attributed to a decrease in atmospheric CO2 concentrations associated with expansion of land plants, as plants both enhance silicate rock weathering—which consumes CO2—and increase the storage of organic carbon on land. However, plant expansion and carbon uptake substantially predate glaciation

The Art and Science of Climate Model Tuning

by Hourdin et al., March 2017,

Bulletin of the American Meteorological Society

We also discuss the challenges and opportunities in applying so-called objective methods in climate model tuning. We discuss how tuning methodologies may affect fundamental results of climate models, such as climate sensitivity. The article concludes with a series of recommendations to make the process of climate model tuning more transparent.

Climate models for the layman

by Judith Curry, Feb 2017


Professor Judith A. Curry is the author of over 180 scienti c papers on weather and climate and is a recipient of the Henry G. Houghton Research Award from the Amer- ican Meteorological Society in 1992. She recently retired from the Georgia Institute of Technology, where she held the positions of Professor and Chair of the School of Earth and Atmospheric Sciences. She is currently President of Climate Forecast Appli- cations Network.

Baby, it’s cold outside: Climate model simulations of the effects of the asteroid impact at the end of the Cretaceous

J.  Brugger, G. Feulner S. Petri  (13 January  2017)


Sixty-six million years ago, the end-Cretaceous mass extinction ended the reign of the dinosaurs. Flood basalt eruptions and an asteroid impact are widely discussed causes, yet their contributions remain debated. Modeling the environmental changes after the Chicxulub impact can shed light on this question. Existing studies, however, focused on the effect of dust or used one-dimensional, noncoupled atmosphere models. Here we explore the longer-lasting cooling due to sulfate aerosols using a coupled climate model. Depending on aerosol stratospheric residence time, global annual mean surface air temperature decreased by at least 26°C, with 3 to 16 years subfreezing temperatures and a recovery time larger than 30 years. The surface cooling triggered vigorous ocean mixing which could have resulted in a plankton bloom due to upwelling of nutrients. These dramatic environmental changes suggest a pivotal role of the impact in the end-Cretaceous extinction.


Also : How the darkness and the cold killed the dinosaurs