Sentences with phrase «radiative forcing a change in»
radiative forcing a change in average net radiation at the top of the troposphere resulting from a change in either solar or infrared radiation due to a change in atmospheric greenhouse gases concentrations; perturbance in the balance between incoming solar radiation and outgoing infrared radiation
https://www.ipcc.ch/
Radiative Forcing A change in average net radiation (in W m - 2) at the top of the troposphere resulting from a change in either solar or infrared radiation due to a change in atmospheric greenhouse gases concentrations; perturbance in the balance between incoming solar radiation and outgoing infrared radiation.
Not exact matches
China's stated aim of improving air quality over the coming years would change this radiative forcing, leading to a rather counter-intuitive consequence; the increase in China's contribution to global warming.
Climate model projections neglecting these changes would continue to overestimate the radiative forcing and global warming in coming decades if these aerosols remain present at current values or increase.
«What is most interesting is that there are big shifts in the surface mass balance that occur from only very small changes in radiative forcing,» said Ullman, who is in OSU's College of Earth, Ocean, and Atmospheric Sciences.
As we explain in our glossary item, climatologists use the concept of radiative forcing and climate sensitivity because it provides a very robust predictive tool for knowing what model results will be, given a change of forcing.
This change in radiative forcing is described as «idealized» by the CMIP group [2].
That is, a change in radiative forcing of about 4 W / m2 would give around 1 °C warming.
Dynamical effects (changes in the winds and ocean circulation) can have just as large an impact, locally as the radiative forcing from greenhouse gases.
While a relatively minor part of the overall aerosol mass, changes in the anthropogenic portion of aerosols since 1750 have resulted in a globally averaged net radiative forcing of roughly -1.2 W / m2, in comparison to the overall average CO2 forcing of +1.66 W / m2.
We can estimate this independently using the changes in ocean heat content over the last decade or so (roughly equal to the current radiative imbalance) of ~ 0.7 W / m2, implying that this «unrealised» forcing will lead to another 0.7 × 0.75 ºC — i.e. 0.5 ºC.
[Response: A similar conclusion to the one cited by Gavin above was reached independently by a panel of scientists (of which I was a member) convened to report on these issues by the National Academy of Sciences last year, resulting in the NAS report «Radiative Forcing of Climate Change: Expanding the Concept and Addressing Uncertainties (2005)».
Forcing caused by changes in the Sun's brightness, by dust in the atmosphere, or by volcanic aerosols can also be translated into radiative fForcing caused by changes in the Sun's brightness, by dust in the atmosphere, or by volcanic aerosols can also be translated into radiative forcingforcing.
Suppose also that — DESPITE THIS STABILIZING MECHANISM some as - yet unknown ocean circulation cycle operates that is the sole cause of the Holocene centennial scale fluctuations, and that this cycle has reversed and is operating today, yielding a temperature change that happens to mimic what models give in response to radiative forcing changes.
Changes in TSI can be converted into a radiative forcing, which tells us the energy imbalance it causes on Earth.
«In today's atmosphere, the radiative forcing from human activities is much more important for current and future climate change than the estimated radiative forcing from changes in natural processes.&raquIn today's atmosphere, the radiative forcing from human activities is much more important for current and future climate change than the estimated radiative forcing from changes in natural processes.&raquin natural processes.»
Where «dT» is the change in the Earth's average surface temperature, «λ» is the climate sensitivity, usually with units in Kelvin or degrees Celsius per Watts per square meter (°C / [W - m - 2]-RRB-, and «dF» is the radiative forcing.
This is a very straightforward and easy to understand formula - the larger the change in solar irradiance, the larger the energy imbalance it causes, and thus the larger the radiative forcing.
If you doubled CO2 and let the system come into equilibrium, the imbalance you'd measure from space would be zero — but there would still be about 4 W / m ** 2 of radiative forcing from the change in CO2.
In addition, researchers calculated the changes in the shortwave and longwave and net radiation between the pre-industrial simulation and the present - day simulations to estimate the radiative forcing resulting from the aerosol effects on cirrus cloudIn addition, researchers calculated the changes in the shortwave and longwave and net radiation between the pre-industrial simulation and the present - day simulations to estimate the radiative forcing resulting from the aerosol effects on cirrus cloudin the shortwave and longwave and net radiation between the pre-industrial simulation and the present - day simulations to estimate the radiative forcing resulting from the aerosol effects on cirrus clouds.
He then uses what information is available to quantify (in Watts per square meter) what radiative terms drive that temperature change (for the LGM this is primarily increased surface albedo from more ice / snow cover, and also changes in greenhouse gases... the former is treated as a forcing, not a feedback; also, the orbital variations which technically drive the process are rather small in the global mean).
Where «dT» is the change in the Earth's average surface temperature, «λ» is the climate sensitivity, usually with units in Kelvin or degrees Celsius per Watts per square meter (°C / [W m - 2]-RRB-, and «dF» is the radiative forcing, which is discussed in further detail in the Advanced rebuttal to the «CO2 effect is weak» argument.
The top priorities should be reducing uncertainties in climate sensitivity, getting a better understanding of the effect of climate change on atmospheric circulation (critical for understanding of regional climate change, changes in extremes) and reducing uncertainties in radiative forcing — particularly those associated with aerosols.
Similarly, many studies that attempt to examine the co-variability between Earth's energy budget and temperature (such as in many of the pieces here at RC concerning the Spencer and Lindzen literature) are only as good as the assumptions made about base state of the atmosphere relative to which changes are measured, the «forcing» that is supposedly driving the changes (which are often just things like ENSO, and are irrelevant to radiative - induced changes that will be important for the future), and are limited by short and discontinuous data records.
The surface temperature change is proportional to the sensitivity and radiative forcing (in W m - 2), regardless of the source of the energy imbalance.
However, in view of the fact that cloud feedbacks are the dominant contribution to uncertainty in climate sensitivity, the fact that the energy balance model used by Schmittner et al can not compute changes in cloud radiative forcing is particularly serious.
«They're pretty evenly distributed across the atmosphere,» said Stephen Montzka, a NOAA scientist who monitors global changes in HFCs and studies their radiative forcing effects over time.
You are arguing that 100ppm change in radiative forcing for CO2, amounting to 0.6 deg C change, multiplied by a wv feedback giving 1.8 deg C change, plays an important part in raising the sea level by 100 meters.
Jo's scientific interests include radiative transfer in the atmosphere, climate modelling, radiative forcing of climate change and the influence of solar irradiance variability on climate.
Abstract:» The sensitivity of global climate with respect to forcing is generally described in terms of the global climate feedback — the global radiative response per degree of global annual mean surface temperature change.
The researchers discovered that periods of increased radiative forcing could produce drought - like conditions that extended indefinitely and that these conditions were closely tied to prolonged changes in Pacific Ocean surface temperatures.
Some other forcings have a very small global radiative forcing and yet lead to large impacts (orbital changes for instance) through components of the climate that aren't included in the default set - up.
Maybe it was due to changes in CO2 radiative forcing (in part) since historical CO2 levels weren't as stable as assumed by the IPCC, at least that's what van Hoof et al. conclude from CO2 data derived from stomatal frequency analysis.
Your earlier # 182 was equally disconcerting where you quoted Norris and Slingo (2009) saying «At present, it is not known whether changes in cloudiness will exacerbate, mitigate, or have little effect on the increasing global surface temperature caused by anthropogenic greenhouse radiative forcing.»
It's a theory now substantiated by physics and observations regarding total radiative forcing and sensitivity, and in our current case of warming attributable to increased forcing agents form human / industrial means we are experiencing a change in trends pertaining to weather events driven by total change factors.
The model results (which are based on driving various climate models with estimated solar, volcanic, and anthropogenic radiative forcing changes over this timeframe) are, by in large, remarkably consistent with the reconstructions, taking into account the statistical uncertainties.
While the local, seasonal climate forcing by the Milankovitch cycles is large (of the order 30 W / m2), the net forcing provided by Milankovitch is close to zero in the global mean, requiring other radiative terms (like albedo or greenhouse gas anomalies) to force global - mean temperature change.
And yet, Simon, you were responding to a set of comments which were about climate sensitivity, for which radiative forcing would be a much more relevant metric — and you responded in a fashion which gave no suggestion that you were changing the topic.
On the possibility of a changing cloud cover «forcing» global warming in recent times (assuming we can just ignore the CO2 physics and current literature on feedbacks, since I don't see a contradiction between an internal radiative forcing and positive feedbacks), one would have to explain a few things, like why the diurnal temperature gradient would decrease with a planet being warmed by decreased albedo... why the stratosphere should cool... why winters should warm faster than summers... essentially the same questions that come with the cosmic ray hypothesis.
Changes in the planetary and tropical TOA radiative fluxes are consistent with independent global ocean heat - storage data, and are expected to be dominated by changes in cloud radiative fChanges in the planetary and tropical TOA radiative fluxes are consistent with independent global ocean heat - storage data, and are expected to be dominated by changes in cloud radiative fchanges in cloud radiative forcing.
As an example of the possible extreme change in radiative forcing in a 50 - year time horizon for Isaken et al (2011)'s 4 x CH4 (i.e. quadrupling the current atmospheric methane burden) case of additional emission of 0.80 GtCH4 / yr is 2.2 Wm - 2, and as the radiative forcing for the current methane emissions of 0.54 GtCH4 / yr is 0.48 Wm - 2, this give an updated GWP for methane, assuming the occurrence of Isaksen et al's 4 x CH4 case in 2040, would be: 33 (per Shindell et al 2009, note that AR5 gives a value of 34) times (2.2 / [0.8 + 0.48]-RRB- divided by (0.54 / 0.48) = 50.
In fact, these past climate changes allow us to learn how sensitive the earth's climate system is to the known radiative forcing that we are producing by increasing the levels of greenhouse gases in the atmospherIn fact, these past climate changes allow us to learn how sensitive the earth's climate system is to the known radiative forcing that we are producing by increasing the levels of greenhouse gases in the atmospherin the atmosphere.
Gerald Marsh offered this opinion in «A Global Warming Primer» (page 4 - excerpt) «Radiative forcing is defined as the change in net downward radiative flux at the tropopause resulting from any process that acts as an external agent to the climate system; it is generally measured iRadiative forcing is defined as the change in net downward radiative flux at the tropopause resulting from any process that acts as an external agent to the climate system; it is generally measured iradiative flux at the tropopause resulting from any process that acts as an external agent to the climate system; it is generally measured in W / m2.
Consequently, as they say slightly earlier in the abstract: «At present, it is not known whether changes in cloudiness will exacerbate, mitigate, or have little effect on the increasing global surface temperature caused by anthropogenic greenhouse radiative forcing.»
Mike's work, like that of previous award winners, is diverse, and includes pioneering and highly cited work in time series analysis (an elegant use of Thomson's multitaper spectral analysis approach to detect spatiotemporal oscillations in the climate record and methods for smoothing temporal data), decadal climate variability (the term «Atlantic Multidecadal Oscillation» or «AMO» was coined by Mike in an interview with Science's Richard Kerr about a paper he had published with Tom Delworth of GFDL showing evidence in both climate model simulations and observational data for a 50 - 70 year oscillation in the climate system; significantly Mike also published work with Kerry Emanuel in 2006 showing that the AMO concept has been overstated as regards its role in 20th century tropical Atlantic SST changes, a finding recently reaffirmed by a study published in Nature), in showing how changes in radiative forcing from volcanoes can affect ENSO, in examining the role of solar variations in explaining the pattern of the Medieval Climate Anomaly and Little Ice Age, the relationship between the climate changes of past centuries and phenomena such as Atlantic tropical cyclones and global sea level, and even a bit of work in atmospheric chemistry (an analysis of beryllium - 7 measurements).
In fact, there is reasonably compelling evidence that changes in drought in the western U.S. over the past millennium may, in large part, reflect the forced response of ENSO to past volcanic and solar radiative forcinIn fact, there is reasonably compelling evidence that changes in drought in the western U.S. over the past millennium may, in large part, reflect the forced response of ENSO to past volcanic and solar radiative forcinin drought in the western U.S. over the past millennium may, in large part, reflect the forced response of ENSO to past volcanic and solar radiative forcinin the western U.S. over the past millennium may, in large part, reflect the forced response of ENSO to past volcanic and solar radiative forcinin large part, reflect the forced response of ENSO to past volcanic and solar radiative forcing.
Abstract:» The sensitivity of global climate with respect to forcing is generally described in terms of the global climate feedback — the global radiative response per degree of global annual mean surface temperature change.
Given the economic tenor of many news stories, an analogy to inflation may be useful in clarifying the idea of slow but steady radiative bracket creep, as the CO2 forcing can be outlined in terms of its effect on the radiative balance, which reduces to watts / M2 and their rate of change.
But models based on physical principles also reproduce the response to seasonal and spatial changes in radiative forcing fairly well, which is one of the many lines of evidence that supports their use in their prediction of the response to anthropogenic forcing.
It is not, in principle, impossible for coupled ocean - atmosphere climate to be chaotic, but all evidence so far points to the likelihood that the strength of the response to GHG radiative forcing changes overwhelms the effect of any chaos there may be in the system.