«
We compare observations and models to figure out how well our models are performing, as well as how we should interpret our space - based observations.»
Not exact matches
These dust particles have surprisingly diverse mineral content
and structure as
compared with
models of interstellar dust based on previous astronomical
observations.
Changes in fall - winter rainfall from
observations (top panel) as
compared to
model simulation of the past century (middle panel),
and a
model projection of the middle of the 21st century.
Nesvorný
and his colleagues followed particles released in their
model from various types of comets or from asteroids
and compared the particles» fates with
observations of the zodiacal dust cloud.
By
comparing the
models to recent
observations of clusters in the Milky Way galaxy
and beyond, the results show that Advanced LIGO (Laser Interferometer Gravitational - Wave Observatory) could eventually see more than 100 binary black hole mergers per year.
The study
compared Simmons»
and other scientists»
models with field
observations and laboratory experiments.
To check their
model forecast, as the dry season has gotten underway, the researchers have
compared their initial forecast with
observations coming in from NASA's precipitation satellite missions» multisatellite datasets, as well as groundwater data from the joint NASA / German Aerospace Center Gravity Recovery
and Climate Experiment (GRACE) mission.
In this technique, scientists initiate a computer
model with data collected before a past event,
and then test the
model's accuracy by
comparing its output with
observations recorded as the event unfolded.
In February, Australian
and American researchers who
compared ocean
and climate
modeling results with weather
observations published findings in Nature Climate Change advancing earlier studies that explored the oscillation's global influence.
Figure 1: Annual average TOA shortwave cloud forcing for present - day conditions from 16 IPCC AR4
models and iRAM (bottom center)
compared with CERES satellite
observations (bottom right)
Various global temperature projections by mainstream climate scientists
and models,
and by climate contrarians,
compared to
observations by NASA GISS.
In fact, the calculation has been done very carefully by Hansen
and co-workers, taking all factors into consideration,
and when
compared with
observations of ocean heat storage over a period long enough for the observed changes to be reliably assessed,
models and observations agree extremely well (see this article
and this article.).
These include using the same
model used to detect the planet instead to fit synthetic, planet - free data (with realistic covariance properties,
and time sampling identical to the real data),
and checking whether the «planet» is still detected;
comparing the strength of the planetary signal with similar Keplerian signals injected into the original
observations; performing Bayesian
model comparisons between planet
and no - planet
models;
and checking how robust the planetary signal is to datapoints being removed from the
observations.
This approach allowed them to
compare the rate
and distribution of warming predicted by
models with those shown in
observations.
Students learn about
and revisit ways to represent
observations and information
and compare the use
and effectiveness of maps,
compare / contrast,
models,
and graphic organizers in presenting
and evaluating data.
Recording
Observations: Have students record their observations about which flooding scenario caused more damage to the model houses and the floodplain, and compare these to the observations of
Observations: Have students record their
observations about which flooding scenario caused more damage to the model houses and the floodplain, and compare these to the observations of
observations about which flooding scenario caused more damage to the
model houses
and the floodplain,
and compare these to the
observations of
observations of their peers.
We don't
compare observations with the same time period in the
models (i.e. the same start
and stop dates), but to all
model projections of the same time length (i.e. 60 - month to 180 - month) trends from the projected data from 2001 - 2020 (from the A1B run)(the trends of a particular length are calculated successively, in one month steps from 2001 to 2020).
Global warming deniers * pull similar dirty tricks with the comparison of global temperature with
model projections — for example, by plotting only the tropical mid-troposphere,
and by
comparing observations with the projections of scenarios which are furthest from reality.
All predictions (whether in a laboratory or natural setting) are based on such
models and it is only from
comparing predictions to
observations that one progresses.
How should one make graphics that appropriately
compare models and observations?
Comparing models to
observations is perfectly fine, but the comparison has to be apples - with - apples
and the analysis has to be a little more sophisticated than saying «look at the lines» (or «linear striations»).
Even with a near - perfect
model and accurate
observations,
model -
observation comparisons can show big discrepancies because the diagnostics being
compared while similar in both cases, actually end up be subtly (
and perhaps importantly) biased.
There is a «
model» which has a certain sensitivity to 2xCO2 (that is either explicitly set in the formulation or emergent),
and observations to which it can be
compared (in various experimental setups)
and, if the data are relevant,
models with different sensitivities can be judged more or less realistic (or explicitly fit to the data).
More interestingly, in response to the second referee's objection that older SRES scenarios were used instead of the new RCP scenarios, Hansen replied: «Our paper
compares observations (thus the past)
and models, thus only deals with the past.
The evaluation of the
model leaves much to be desired: no differences are shown
compared with
observations,
and some errors are large.
A detailed reanalysis is presented of a «Bayesian» climate parameter study (Forest et al., 2006) that estimates climate sensitivity (ECS) jointly with effective ocean diffusivity
and aerosol forcing, using optimal fingerprints to
compare multi-decadal
observations with simulations by the MIT 2D climate
model at varying settings of the three climate parameters.
As has been noted by others, this is
comparing model temperatures after 2020 to an
observation - based temperature in 2015,
and of course the latter is lower — partly because it is based on HadCRUT4 data as discussed above, but equally so because of
comparing different points in time.
All in all the science of hurricanes does appear to be much more fun
and interesting than the average climate change issue, as there is a debate, a «fight» between different hypothesis, predictions
compared to near - future
observations,
and all that does not always get pre-eminence in the exchanges about
models.
See Stowasser & Hamilton, Relationship between Shortwave Cloud Radiative Forcing
and Local Meteorological Variables
Compared in
Observations and Several Global Climate
Models, Journal of Climate 2006; Lauer et al., The Impact of Global Warming on Marine Boundary Layer Clouds over the Eastern Pacific — A Regional
Model Study, Journal of Climate 2010.
Forest et al. 2006
compares observations of multiple surface, upper air
and deep - ocean temperature changes with simulations thereof by the MIT 2D climate
model run at many climate parameter settings.
Scientists use data gathered from ARM's fixed, mobile,
and aerial facilities worldwide to address these issues
and compare the
observations to their
models.
The researchers focused on
comparing model projections
and observations of the spatial
and seasonal patterns of how energy flows from Earth to space.
One could take the outcomes of different starting conditions, or use of different
model parameters,
and compare them against
observations.
Researchers looking to
compare climate
model - simulated clouds
and cloud
observations from the ARM Climate Research Facility can access a helpful new tool.
Consequently, short of waiting until after climate change has occurred, the best guide we have for judging
model reliability is to
compare model results with
observations of present
and past climates.Our lack of knowledge about the real climate makes it difficult to verify
models.
The scientists, using computer
models,
compared their results with
observations and concluded that global average annual temperatures have been lower than they would otherwise have been because of the oscillation.
The radiative flux predicted by the HIRLAM weather
model was
compared to
observations made in Jokioinen
and Sodankylä.
And Ed
compares CMIP5
models with updated
observations; but instead of evidencing the «pause» some researches keep watching that figure as an evidence of global warming.
Revisionist
and / or «still consistent with
observations»: in terms of changing the assumptions, changing the amount of time necessary for a pause to be significant, changing tack to OHC,
comparing real earth to the spread of all
models, etc..
We
compare the output of various climate
models to temperature
and precipitation
observations at 55 points around the globe.
Santer (2003)
compares the rise of the tropopause from 1979 - 1999 from
observations (reanalysis) to the rise calculated by a
model driven by anthropogenic
and non-anthropogenic forcings.
The motivation for this paper is twofold: first, we validate the
model's performance in the Gulf of Mexico by
comparing the
model fields to past
and recent
observations,
and second, given the good agreement with the observed Gulf of Mexico surface circulation
and Loop Current variability, we expand the discussion
and analysis of the
model circulation to areas that have not been extensively observed / analyzed, such as the vertical structure of the Loop Current
and associated eddies, especially the deep circulation below 1500 m.
This paper covers the historical experiments —
comparing model results from 850-2005 to
observations and proxy reconstructions — as well as some idealized experiments designed to measure metrics such as climate sensitivity, transient climate response,
and carbon cycle feedbacks.
I haven't seen a study that
compared the number of studies based upon actual
observations as
compared to
model studies
and sensitivity beliefs either come to think of it.
Because the
models are not deterministic, multiple simulations are needed to
compare with
observations,
and the number of simulations conducted by
modeling centers are insufficient to create a pdf with a robust mean; hence bounding box approaches (assessing whether the range of the ensembles bounds the
observations) are arguably a better way to establish empirical adequacy.
We
compare aircraft
observations to
modeled CH4 distributions by accounting for a) transport using the Stochastic Time - Inverted Lagrangian Transport (STILT)
model driven by Weather Research
and Forecasting (WRF) meteorology, b) emissions from inventories such as EDGAR
and ones constructed from California - specific state
and county databases, each gridded to 0.1 ° x 0.1 ° resolution,
and c) spatially
and temporally evolving boundary conditions such as GEOS - Chem
and a NOAA aircraft profile measurement derived curtain imposed at the edge of the WRF domain.
The
model's ensemble - mean EOF accounts for 43 % of the variance on average across the 40 ensemble members,
and is largely similar to
observations although the centers - of - action extend slightly farther east
and the southern lobe is weaker (maximum amplitude of approximately 2 hPa
compared to 3 hPa in
observations; Fig. 3c).
As I said, when
comparing with
observations over the short period being considered here, it makes more sense to
compare with
models that include natural internal variability (i.e.: GCMs — as in the final version) than against models that do not include this and only include externally - forced changes (ie: Simple Climate Models, SCMs, — as in the SOD ver
models that include natural internal variability (i.e.: GCMs — as in the final version) than against
models that do not include this and only include externally - forced changes (ie: Simple Climate Models, SCMs, — as in the SOD ver
models that do not include this
and only include externally - forced changes (ie: Simple Climate
Models, SCMs, — as in the SOD ver
Models, SCMs, — as in the SOD version).
«In the case of the Arctic we have high confidence in
observations since 1979, from
models (see Section 9.4.3
and from simulations
comparing with
and without anthropogenic forcing),
and from physical understanding of the dominant processes; taking these three factors together it is very likely that anthropogenic forcing has contributed to the observed decreases in Arctic sea ice since 1979.»
This month's report includes a compilation of ship - based
observations from the Geographic Information Network of Alaska IceWatch program, a discussion of the August
modeling contributions
and how they
compare to June
and July, a look at the predictions in specific regions,
and a discussion of current ice
and weather conditions.