The implication is that over a short period,
the weather noise can mask significant differences in the forced component.
Kleeman, R., Y. Tang, and A.M. Moore, 2003: The calculation of climatically relevant singular vectors in the presence of
weather noise as applied to the ENSO problem.
Claiming that the forced climate response must be larger than
the weather noise for climate prediction on all time scales is just silly.
It is easy to see that unpredictable
weather noise dominates short term variability.
Specifically,
any weather noise over the last 30 years in the troposphere must hold for the surface as well.
[Response: Over short periods the size of
the weather noise is significantly larger than the structural differences in the models.
Using the broad uncertainty you provide for the models (
weather noise, etc.), I calculate that the T2LT and T2 means deviate from the model means at the level of 1.25 and 1.26 (sigma - means), respectively.
Are you really claiming that models perfectly simulate «internal model
weather noise»?
While this methodology doesn't eliminate your point that the trends from different periods in the observed record (or from different observed datasets) fall at various locations within our model - derived 95 % confidence range (clearly they do), it does provide justification for using the most recent data to show that sometimes (including currently), the observed trends (which obviously contain natural variability, or,
weather noise) push the envelop of model trends (which also contain
weather noise).
(bear in mind a well that there are multiple simulations and that
weather noise causes substantial spread over short periods of time).
The early part of the century is still buried in the noise a bit; sort of like
weather noise is buried in climate signal.
if you had listen to what people told you about
the weather noise in short term climate observations or about SIGNIFICANT timescales in this discussion, you wouldn't be wrong on yet another point.
Because the magnitude of the counter acting effects depends on the degree of non-linearity, the rms of the residuals to a linear fit, the length of the trend and the temporal auto - correlation of the «
weather noise», it is difficult to generalize whether the method will generally result in too many false positives or negatives.
Yes, the Arctic warms and cools in consonant with the rest of the globe, but with much local excursions and plenty of
weather noise and cyclical climate perturbations contributing to the overall picture.
I think that a more scientifically justifiable statement, at least for the U.S. and extratropical land areas is that daily
weather noise continues to drum out the siren call of climate change on local, weather scales.
The models also produce their own such
weather noise.
Nowadays we would use an ensemble of runs with slightly perturbed initial conditions (usually a different ocean state) in order to average over «
weather noise» and extract the «forced» signal.
As mentioned above, with a single realisation, there is going to be an amount of
weather noise that has nothing to do with the forcings.
My opinion, judging from the amount of unforced (and hence unpredictable)
weather noise is that you would not have been able to say that even a perfect model was clearly better than this.
The implication is that over a short period,
the weather noise can mask significant differences in the forced component.
These were single realisations, and so don't have an ensemble envelope around them (which is how we would assess the uncertainty due to
weather noise today).
Using 12 - month averages eliminates the seasonal and
weather noise.
But right now they're not much different than the short - term
weather noise we've seen previously.
I would really like some clarity as to how the ensemble of model runs are whittled down into a narrower subset without comprimising the ability of the model to «span the full range» of «
weather noise».
(2) In general, any year's global temperature that is «on trend» should be exceeded within 5 years (when size of trend exceeds «
weather noise»)
As far as «climate» goes, a 30 year smooth reduces most on
the weather noise giving you something to fit with a reasonable error range so you don't have to magnify some obscure signal by a factor of ten to get a «fit».
Nevertheless, the simplistic notion that climate variations consist of an analytic trend plus multidecadal periodic cycles hidden by higher - frequency «
weather noise» remains endemic among those who feature themselves as «climate scientists.»
We can estimate value of
weather noise by computing the classical deviation from the mean.
This value of
the weather noise is only valid for this weather station.
I have analyzed the temperature data of Sept 21 from the weather station at Quatsino, BC for the 1895 -2009 interval and have obtained a value of + / - 1.5 K of
weather noise for both Tmax and T min.
This indicates that random
weather noise played a very large role in December's weather.
It included an animation of the HADSST2 SST anomalies for 1939 through 1947, using maps of 12 - month average data to reduce the seasonal component and
weather noise.
Isn't this topic yet another indication that for purposes of making climate - related predictions, the signal / noise paradigm of temperature signal versus
weather noise is a completely flaky proposition — all of it, the whole signal / noise paradigm.
This «
weather noise» is assumed to be obtained from the calculations even tho the models / codes / application procedures do not resolve «weather».
If we assume
weather noise IS AR (1) and has the lag - 1 correlation that gives the variability in 8 year trends Gavin gets, then you can prove the monthly weather data since 2001 is an outlier.
Yeah, it's 10 - year long
weather noise.
The other model I looked at (The canadian one) didn't have as much «
weather noise» in GMST.
Additionally, the temporal variations in a global solution meta - functional are assigned to «
weather noise».
That is exactly what Schmidt is doing when he is «generating»
weather noise in his GCMs even if the model does something infinitely crudest than DNS.
For example, Echo - G seems to have a huge amount of
weather noise at the GMST level which sets it apart from other models.
Warming and cooling signals in
weather noise is not so easy to determine as to the cause.
AR5 3.2.2.3 says of it «Overall, the SST data should be regarded as more reliable because averaging of fewer samples is needed for SST than for HadMAT to remove synoptic
weather noise.
The figure below the jump shows what happens when we apply such a correction (note: we maintain some internal
weather noise).
From this, they conclude that there's a corner frequency somewhere, and everything above this corner frequency is
weather noise, and everything below this corner frequency is climate signal.
It is easy to see that unpredictable
weather noise dominates short term variability.
So the longer the averaging time - period and the wider the spatial average, the smaller
the weather noise and the greater chance to detect any particular signal.
I am convinced they don't know what they are doing when it comes to internal climate variability («
weather noise») and statistical treatment of ensemble GCM runs.
This difference in temperature, less
weather noise, would obviously be a reflection of the trend.
Not exact matches
The challenge lies in the fact that natural variability is always a part of any extreme
weather event, so when scientists do attribution exercises, they are trying to discern the human signal out of the
noise.