Sentences with phrase «large changes in surface temperature»

Not exact matches

Tamsin Edwards, a climatologist at the Open University in the UK, says it is too early to tell, since changes in the PDO can only be detected through statistical analysis of large amounts of data on ocean surface temperatures.

There are strong competing effects such as changes in the large - scale atmospheric circulation, sea surface temperature changes like El Niño and La Niña and the dynamics of westerly storm tracks that all interact at the mid-latitudes,» said Stanford co-author Matthew Winnick who contributed to the study with fellow doctoral student Daniel Ibarra.

As discussed in the Climate chapter, large - scale atmospheric circulation patterns connected to changes in sea - surface temperatures strongly influence natural variations in precipitation and temperature (e.g., Cayan et al. 1999; Mantua and Hare 2002).

Scientists use a large drill to remove parts of the coral to analyse for information about changes in rainfall and sea surface temperature.

For significant periods of time, the reconstructed large - scale changes in the North Pacific SLP field described here and by construction the long - term decline in Hawaiian winter rainfall are broadly consistent with long - term changes in tropical Pacific sea surface temperature (SST) based on ENSO reconstructions documented in several other studies, particularly over the last two centuries.

During El Nino events the ocean circulation changes in such a way as to cause a large and temporary positive sea surface temperature anomaly in the tropical Pacific.

The substantial uncertainties currently present in the quantitative assessment of large - scale surface temperature changes prior to about A.D. 1600 lower our confidence in this conclusion compared to the high level of confidence we place in the Little Ice Age cooling and 20th century warming.»

This conclusion has subsequently been supported by an array of evidence that includes the additional large - scale surface temperature reconstructions and documentation of the spatial coherence of recent warming described above (Cook et al. 2004, Moberg et al. 2005b, Rutherford et al. 2005, D'Arrigo et al. 2006, Osborn and Briffa 2006, Wahl and Ammann in press) and also the pronounced changes in a variety of local proxy indicators described in previous chapters (e.g., Thompson et al. in press).

There are two very basic answers: First, looking at changes in data gets rid of biases at individual stations that don't change in time (such as station location), and second, for surface temperatures at least, the correlation scale for anomalies is much larger (100's km) than for absolute temperatures.

So, it follows on phtysical grounds that any temperature change at the surface gets amplified aloft which means that the variability in temperature (solely the «dry» energy term) is larger aloft than at the surface.

The paleoclimate record (8.2 kyr, and earlier «large lake collapses») shows a dramatic drop in surface temperatures for a substantial period of time when the ocean circulation shuts off or changes, but is that actually what would be expected under these warming conditions?

The paper he wrote together with Friis - Christensen in which he found a correlation between solar activity and clouds had a «slight» flaw: it ignored that the period of the study coincided with a big El Nino, and that large scale changes in ocean surface temperature are going to have an effect on cloud formation.

Before allowing the temperature to respond, we can consider the forcing at the tropopause (TRPP) and at TOA, both reductions in net upward fluxes (though at TOA, the net upward LW flux is simply the OLR); my point is that even without direct solar heating above the tropopause, the forcing at TOA can be less than the forcing at TRPP (as explained in detail for CO2 in my 348, but in general, it is possible to bring the net upward flux at TRPP toward zero but even with saturation at TOA, the nonzero skin temperature requires some nonzero net upward flux to remain — now it just depends on what the net fluxes were before we made the changes, and whether the proportionality of forcings at TRPP and TOA is similar if the effect has not approached saturation at TRPP); the forcing at TRPP is the forcing on the surface + troposphere, which they must warm up to balance, while the forcing difference between TOA and TRPP is the forcing on the stratosphere; if the forcing at TRPP is larger than at TOA, the stratosphere must cool, reducing outward fluxes from the stratosphere by the same total amount as the difference in forcings between TRPP and TOA.

(Within the range where water vapor feedback is runaway, zero change in external forcing»cause s» a large change in climate; the equilibrium surface temperature, graphed over some measure of external forcing, takes a step at some particular value.)

If the surface temperature is slow to catch up to that imbalance then the energy imbalance remains large, and we can have sufficient net heating to cause much faster changes in the ice sheets than from the comparatively smaller imbalances caused by the changes in Earth's orbit associated with the glacial periods in the past.

The ability of a band to shape the temperature profile of the whole atmosphere should tend to be maximum at intermediate optical thicknesses (for a given band width), because at small optical thicknesses, the amounts of emission and absorption within any layer will be small relative to what happens in other bands, while at large optical thicknesses, the net fluxes will tend to go to zero (except near TOA and, absent convection, the surface) and will be insensitive to changes in the temperature profile (except near TOA), thus allowing other bands greater control over the temperature profile (depending on wavelength — greater influence for bands with larger bandwidths at wavelengths closer to the peak wavelength — which will depend on temperature and thus vary with height.

The second aspect of climate change that is likely affecting Alaska more and more is the apparent tendency of warming in the Arctic and warmer sea surface temperatures in the Pacific to contribute to larger waves in the jet stream.

Is the past 10 to 15 years — which have seen little net change in the average surface temperature of the Earth despite ever - larger carbon dioxide emissions — an indication that climate change will not be as bad as previously projected?

But it does say; «Natural climate variations, which tend to involve localized changes in sea surface temperature, may have a larger effect on hurricane activity than the more uniform patterns of global warming...»

Many models have large biases in lower stratospheric water vapour (Gettelman et al., 2010), which could have implications for surface temperature change (Solomon et al., 2010).

Large uncertainties in surface temperature change may exist at every single grid point of the Earth.

The overall level of consistency between attribution results derived from different models (as shown in Figure 9.9), and the ability of climate models to simulate large - scale temperature changes during the 20th century (Figures 9.5 and 9.6), indicate that such model differences are likely to have a relatively small impact on attribution results of large - scale temperature change at the surface.

Note: The step change (temperature drop) at 1945 has been identified as an error in a recent Thompson et al letter to «Nature» with the title «A Large Discontinuity in the Mid-Twentieth Century in Observed Global - Mean Surface Temperattemperature drop) at 1945 has been identified as an error in a recent Thompson et al letter to «Nature» with the title «A Large Discontinuity in the Mid-Twentieth Century in Observed Global - Mean Surface TemperatureTemperature».

Going forwards CO2 forcing is several times larger than the LIA solar forcing which was itself measurable in the surface temperature record, so we expect CO2 forcing to be measurable for sure, and yes, it will be accompanied by some effects of changing clouds too, but we don't know which direction they would push it.

Given the vast pool of very cold water in the deep ocean, even modest changes in the rate it exchanges heat with the surface can produce large changes in temperature without any change in the planetary radiative balance.

Even in areas where precipitation does not decrease, these increases in surface evaporation and loss of water from plants lead to more rapid drying of soils if the effects of higher temperatures are not offset by other changes (such as reduced wind speed or increased humidity).5 As soil dries out, a larger proportion of the incoming heat from the sun goes into heating the soil and adjacent air rather than evaporating its moisture, resulting in hotter summers under drier climatic conditions.6

We further estimate that, in most northern hemispheric regions, these changes in the likelihood of extreme summer mean WBGT are roughly an order of magnitude larger than the corresponding changes in the likelihood of extreme hot summers as simply measured by surface air temperature.

This may seem like a small number compared to changes in daily temperature however to put it into comparison how small global temperature changes can have a large effect, if the Earth's surface temperature was lowered by 5 ⁰ C it would be in a full ice age.

We use a one - dimensional radiative - convective model for the atmospheric thermal structure to compute the change in the surface temperature of the earth for large assumed increases in the trace gas concentrations; doubling the N2O, CH4, and NH3 concentrations is found to cause additive increases in the surface temperature of 0.7 °, 0.3 °, and 0.1 ° K, respectively.

The slowed surface warming is due in large part to changes in ocean cycles, particularly in the Pacific Ocean, causing more efficient ocean heat uptake, thus leaving less heat to warm surface temperatures.

Dessler (2011) used observational data (such as surface temperature measurements and ARGO ocean temperature) to estimate and corroborate these values, and found that the heating of the climate system through ocean heat transport was 20 times larger than TOA energy flux changes due to cloud cover over the period in question.

This conclusion has subsequently been supported by an array of evidence that includes the additional large - scale surface temperature reconstructions and documentation of the spatial coherence of recent warming described above (Cook et al. 2004, Moberg et al. 2005b, Rutherford et al. 2005, D'Arrigo et al. 2006, Osborn and Briffa 2006, Wahl and Ammann in press) and also the pronounced changes in a variety of local proxy indicators described in previous chapters (e.g., Thompson et al. in press).

The NAO's prominent upward trend from the 1950s to the 1990s caused large regional changes in air temperature, precipitation, wind and storminess, with accompanying impacts on marine and terrestrial ecosystems, and contributed to the accelerated rise in global mean surface temperature (e.g., Hurrell 1996; Ottersen et al. 2001; Thompson et al. 2000; Visbeck et al. 2003; Stenseth et al. 2003).

This conclusion has subsequently been supported by an array of evidence that includes both additional large - scale surface temperature reconstructions and pronounced changes in a variety of local proxy indicators, such as melting on icecaps and the retreat of glaciers around the world, which in many cases appear to be unprecedented during at least the last 2000 years.

Importantly, the changes in cereal yield projected for the 2020s and 2080s are driven by GHG - induced climate change and likely do not fully capture interannual precipitation variability which can result in large yield reductions during dry periods, as the IPCC (Christensen et al., 2007) states: ``... there is less confidence in the ability of the AOGCMs (atmosphere - ocean general circulation models) to generate interannual variability in the SSTs (sea surface temperatures) of the type known to affect African rainfall, as evidenced by the fact that very few AOGCMs produce droughts comparable in magnitude to the Sahel droughts of the 1970s and 1980s.»

The use of even more recently computer - reconstructed total solar irradiance data (whatever have large uncertainties) for the period prior to 1976 would not change any of the conclusions in my paper, where quantitative analyses were emphasized on the influences of humans and the Sun on global surface temperature after 1970 when direct measurements became available.

Change in entropy at the surface is a large negative value, because we have to consider the source temperature of the energy.

The basic conclusion of Mann et al. (1998, 1999) that the late 20th century warmth in the Northern Hemisphere was unprecedented during at least the last 1,000 years has subsequently been supported by an array of evidence that includes both additional large - scale surface temperature reconstructions and pronounced changes in a variety of local proxy indicators

Judith writes: «Relative to the broader issue of attribution, which are at the heart of skeptical concern, details of the surface temperature record don't play a terribly large role in most people's skepticism about climate change.»

Also Wentz neglects the fact that small changes in relative humidity or difference between surface and near air temperatures can result in large changes in evaporation rates based on their equation (1) which determines evaporation rate.

The large interannual to decadal hydroclimatic variability in winter precipitation is highly influenced by sea surface temperature (SST) anomalies in the tropical Pacific Ocean and associated changes in large - scale atmospheric circulation patterns [16].

«From 1910 - 1949 (pre-agricultural development, pre-DEV) to 1970 - 2009 (full agricultural development, full - DEV), the central United States experienced large - scale increases in rainfall of up to 35 % and decreases in surface air temperature of up to 1 °C during the boreal summer months of July and August... which conflicts with expectations from climate change projections for the end of the 21st century (i.e., warming and decreasing rainfall)(Melillo et al., 2014).»

Had Hansen used a climate model with a climate sensitivity of approximately 3.4 °C for 2xCO2 (at least in the short - term, it's likely larger in the long - term due to slow - acting feedbacks), he would have projected the ensuing rate of global surface temperature change accurately.

Although documented changes in global surface temperatures during the Holocene and Common era are relatively small, the concomitant changes in OHC are large.»

Table 1 shows the resulting contributions to the global surface temperature changes which are illustrated graphically in Figure 1 [Note: click on Table 1 for a larger version].

It may not be relevant but it should be pointed out that the changes in surface temperature during the period in question have a very large uncertainty.

It would clearly be inappropriate to regress surface temperature changes on forcing changes for the reasons you give, since relative uncertainty in forcing changes is much larger than that in temperature changes.

A small localized change in surface temperature can cause a convection burst (thunderstorm) and a large increase in convection height, improving both reflection of incoming solar radiation, and conveying sensible heat to a higher altitude where it can then escape to space via radiative processes with far less interference.

http://www.agci.org/docs/lean.pdf «Global (and regional) surface temperature fluctuations in the past 120 years reflect, as in the space era, a combination of solar, volcanic, ENSO, and anthropogenic influences, with relative contributions shown in Figure 6.22 The adopted solar brightness changes in this scenario are based on a solar surface flux transport model; although long - term changes are «50 % larger than the 11 - year irradiance cycle, they are significantly smaller than the original estimates based on variations in Sun - like stars and geomagnetic activity.

Climate model simulations indicate that changes in solar radiation a few times larger than those confirmed in the eleven - year cycle, and persisting over multi-decadal time scales, would directly affect the surface temperature.