Because the other open thread is getting pretty full.
Entries from June 2008
The Big Thaw
June 12, 2008 · 182 Comments
The blogosphere is buzzing with discussion of new research soon to be published in Geophysical Research Letters, Accelerated Arctic land warming and permafrost degradation during rapid sea ice loss (Lawrence et al. 2008, GRL, in press, scheduled for publication tomorrow), a collaboration between researchers from NCAR (National Center for Atmospheric Research) and NSIDC (National Snow and Ice Data Center). Their research indicates that, in large part due to the rapid reduction of summer sea ice in the arctic, land areas in the far north will warm much faster than the rest of the globe. This would lead to rapid melting of permafrost, which in turn could release massive stores of CO2 trapped in the permafrost.
Categories: Global Warming
Hurst
June 10, 2008 · 27 Comments
When doing trend analysis, one of the most common ways to compensate for autocorrelation in the data is to compute an “effective number” of data points when estimating the uncertainty of the trend value, rather than simply use the raw number of data. To compute the effective number, we begin by computing the number of data points per degree of freedom as
where 
Then, when computing the uncertainty in our estimated trend rate, we substitute 
Categories: Global Warming
Victoria Rainfall Fall Rain
June 8, 2008 · 52 Comments
On the thread about drought in Australia, Greg writes:
If you want to take on bodgy statistics Tamino, look no further than this one:“Research by CSIRO scientists Wenju Cai and Tim Cowan has detected that, since 1950, Victoria has suffered a 40 per cent decline in autumn rainfall compared with the long-term average.”
Compare and contrast the reality:
http://www.bom.gov.au/cgi-bin/silo/reg/cli_chg/timeseries.cgi?variable=rain®ion=vic&season=0305
The link is to this graph from the Australian Bureau of Meteorology (BoM):
The blue bars show the annual values, the black line shows an 11-yr moving average. Apparently Greg thinks this graph contradicts the assertion that autumn rainfall has declined significantly in Victoria. But does it? Let’s take a closer look.
Categories: Global Warming
