Archive

Posts Tagged ‘climate models’

UVic_ESCM: Flowchart Sketch 1

2012 February 12 Comments off


Way back in the day, as a new hire, in one of my first ‘think outside of the box’ exercises, I color formatted and hyper-linked a bunch of FORTRAN code. A large and aging defense project, there was a lot of it and my pet project quickly became a preferred method within the team for browsing the code. Ah … recall the days when Slackware came on several dozen floppy disks that you downloaded yourself.

Confronted with the UVIC_ESCM code, I wasn’t sure where to start to digest it. Eventually I decided to parse out its calling structure. It’s not a pretty chart. It might not even be complete or accurate. But its a start. Don’t bother clicking ‘more’. I promise it won’t be of any interest to any of you! (Except maybe Kate or Steve :D )

Read more…

UVic_ESCM 2.8 Build Notes

2011 November 27 Comments off


A new earth system climate model of intermediate complexity has been developed and its climatology compared to observations. The UVic Earth System Climate Model consists of a three-dimensional ocean general circulation model coupled to a thermodynamic/dynamic sea-ice model, an energy-moisture balance atmospheric model with dynamical feedbacks, and a thermomechanical land-ice model. In order to keep the model computationally efficient a reduced complexity atmosphere model is used. Atmospheric heat and freshwater transports are parametrized through Fickian diffusion, and precipitation is assumed to occur when the relative humidity is greater than 85%. Moisture transport can also be accomplished through advection if desired. Precipitation over land is assumed to return instantaneously to the ocean via one of 33 observed river drainage basins. Ice and snow albedo feedbacks are included in the coupled model by locally increasing the prescribed latitudinal profile of the planetary albedo. The atmospheric model includes a parametrization of water vapour/planetary longwave feedbacks, although the radiative forcing associated with changes in atmospheric CO2 is prescribed as a modification of the planetary longwave radiative flux. A specified lapse rate is used to reduce the surface temperature over land where there is topography. The model uses prescribed present-day winds in its climatology, although a dynamical wind feedback is included which exploits a latitudinally-varying empirical relationship between atmospheric surface temperature and density. The ocean component of the coupled model is based on the Geophysical Fluid Dynamics Laboratory (GFDL) Modular Ocean Model 2.2, with a global resolution of 3.6° (zonal) by 1.8° (meridional) and 19 vertical levels, and includes an option for brine-rejection parametrization. The sea-ice component incorporates an elastic-viscous-plastic rheology to represent sea-ice dynamics and various options for the representation of sea-ice thermodynamics and thickness distribution. The systematic comparison of the coupled model with observations reveals good agreement, especially when moisture transport is accomplished through advection.

The UVic Earth System Climate Model: Model Description, Climatology, and Applications to Past, Present and Future Climates
Andrew J. Weaver, Michael Eby, Edward C. Wiebe, Cecilia M. Bitz, Phil B. Duffy,
Tracy L. Ewen, Augustus F. Fanning, Marika M. Holland, Amy MacFadyen, H. Damon Matthews,
Katrin J. Meissner, Oleg Saenko, Andreas Schmittner, Huaxiao Wang and Masakazu Yoshimori (2001)
http://mgg.coas.oregonstate.edu/~andreas/pdf/W/weaver01ao.pdf

Read more…

Science Daily: Tropics: Global Warming Likely to Significantly Affect Rainfall Patterns

2010 February 28 Comments off

ScienceDaily (Feb. 28, 2010) — Climate models project that the global average temperature will rise about 1°C by the middle of the century, if we continue with business as usual and emit greenhouse gases as we have been. The global average, though, does not tell us anything about what will happen to regional climates, for example rainfall in the western United States or in paradisical islands like Hawai’i.

Read more…

Steve Goddard's Snowjob

2010 February 27 10 comments

Introduction

In the last several weeks, Steve Goddard has posted a series of threads on WUWT on Northern Hemisphere snow cover extent. (see here and here and here and here.) In one entitled North American snow models miss the mark – observed trend opposite of the predictions, Goddard uses data from Rutger’s Global Snow Lab to claim that the latest 22-year trend for Winter (Dec, Jan, Feb) in the Northern Hemisphere invalidates the CMIP3 modeling of snow extent as presented by Frei and Gong in 2005 in their paper Decadal to Century Scale Trends in North American Snow Extent in Coupled Atmosphere-Ocean General Circulation Models. This paper is summarized at a Columbia University web page Will Climate Change Affect Snow Cover Over North America?

Read more…

The Blunt Skippy

2010 February 16 Comments off

Joe Romm at Climate Progress is looking for ideas to populate his new Climate Science project (here and here). This reminded me of an old page I posted called the Four Points of AGW aka The Blunt Skippy. It sketches out the basics of AGW theory. Real Climate did a similar, but better page in six easy points.

Read more…

Follow

Get every new post delivered to your Inbox.

Join 27 other followers