Sentences with phrase «net of albedo»

As for the Keil & Trenberth cartoon, reproduced on p. 58 of Houghton's 1996 text, the sum of inputs into the atmosphere, net of albedo and the 168 W / m ^ 2 of direct isnolation that you cite, is clearly 519.

Not exact matches

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.

Does more evaporation lead to more clouds and if so is the net effect of more clouds to increase albedo or to further increase GHE?

It melts without having much cooling effect, and in short order there is net warming because of the reduced albedo of wet snow vs. dry snow and bare rock vs. snow cover.

This is what I get out of it: the Arctic - ice - albedo situation is more complicated than earlier thought (due to clouds, sun - filled summers, dark winters, etc), but NET EFFECT, the ice loss and all these other related factors (some negative feedbacks) act as a positive feedback and enhance global warming.

Our observational studies (Gray and Schwartz, 2010 and 2011) of the variations of outward radiation (IR + albedo) energy flux to space (ISCCP data) vs. tropical and global precipitation increase (from NCEP reanalysis data) indicates that there is not a reduction of global net radiation (IR + Albedo) to space which is associated with increased global or tropical - regional raialbedo) energy flux to space (ISCCP data) vs. tropical and global precipitation increase (from NCEP reanalysis data) indicates that there is not a reduction of global net radiation (IR + Albedo) to space which is associated with increased global or tropical - regional raiAlbedo) to space which is associated with increased global or tropical - regional rainfall.

The albedo enhancement over the cloud - rain areas tends to increase the net (IR + albedo) radiation energy to space more than the weak suppression of (IR + albedo) in the clear areas.

I believe we all agree that sea ice has an empirically observed higher albedo than sea water, so that a significant net melting of sea ice should lower the average albedo of Earth.

The albedo change resulting from the snowline retreat on land is similarly large as the retreat of sea ice, so the combined impact could be well over 2 W / sq m. To put this in context, albedo changes in the Arctic alone could more than double the net radiative forcing resulting from the emissions caused by all people of the world, estimated by the IPCC to be 1.6 W / sq m in 2007 and 2.29 W / sq m in 2013.»

One of the most puzzling things is that the heating between 1980 and 2000 seems to have been driven by a large increase in net received shortwave radiation due to albedo reduction, rather than by any observed reduction in outgoing longwave radiation.

Six Chinese scientists used remotely - sensed imaging data, including leaf area index (LAI), normalized difference vegetation index (NDVI), an enhanced vegetation index (EVI), gross primary production (GPP) and net primary production (NPP), coupled with other data (temperature, soil moisture, evapotranspiration, albedo and wind) over the period 2003 to 2014 to analyze the effects of a wind farm on summer vegetative growth in a region of northern China.

You would do better to discuss why FG were not sure of their result for various practical reasons, e.g. the net radiative flux imbalance at the top of the atmosphere has only been measured for a very short time, and their study doesn't include albedo forcings from melting ice — if you're actually as interested in their results as you pretend to be.

The Milankovitch cycles are weak from the point of view of net solar forcing, but they affect the albedo through systematic changes in northern ice cover during the months when there is more daylight.

If the net result of more open water was dominated by albedo and positive then we would have seen a rapid acceleration after 2007 and more after 2012.

The 30 % is used on the left hand side of this exceedingly simple equation to determine the net radiations hitting the atmosphere and surface taking into account earth albedo.

The jets achieve their effect by altering the flow of energy through the troposphere but in doing so they alter albedo so, depending on the overall net situation, if another forcing increases or decreases albedo then the jets may not have to shift so far or the jets may need to move a bit further depending on the net balance at the time.

In the IPCC summary there's a figure indicating land use (albedo) is responsible for a net forcing of -0.25 W / m2, with an uncertainty range of 0 to -0.5 W / m2 (the figure also indicates that scientific understanding of albedo is very low).

An aside: one of the reasons that clouds modulate temperature so effectively is not just the albedo increase which bounces downwelling short wave radiation back into space, but because they radiate IR back to the surface thus reducing the net rate of thermal radiative loss.»

http://earthobservatory.nasa.gov/IOTD/view.php?id=83672 http://www.nytimes.com/2014/05/13/science/earth/collapse-of-parts-of-west-antarctica-ice-sheet-has-begun-scientists-say.html It will add about 10 feet according to an interview with one of the scientists involved; but over a long time and fairly vague time frame, unless reinforcing processes (carbon release from melting permafrost, shallow ocean bottom warmingn in the form of methane from clathrates), a major reduction in earth's albedo from permafrost, net ice sheet, and total sea ice, continue to increasingly accelerate the process.

An aside: one of the reasons that clouds modulate temperature so effectively is not just the albedo increase which bounces dowelling short wave radiation back into space, but because they radiate IR back to the surface thus reducing the net rate of thermal radiative loss.

When you compare this with the actual surface temperature of ~ 288 K and the temperature in absence of the greenhouse effect but no change in albedo of ~ 255 K, what we can say is the follows: The greenhouse effect due to all the greenhouse gases (water vapor, clouds, and the long - lived GHGs like CO2 and CH4) raises the temperature of the Earth by an amount of ~ 33 K (which is 288K — 255K); the albedo due to cloud reduces the temperature by ~ 17 K (which is 272 K — 255 K); the net effect of both the GHGs and the cloud albedo is ~ 16 K (which is 288K — 272K).

Land cover changes, largely due to net deforestation, have increased the surface albedo giving an RF of — 0.2 [± 0.2] W m — 2, with a medium - low level of scientific understanding.

They found that changes in atmospheric ionization during the 11 - year solar cycle, and the resulting variations in aerosol formation, produced a globally asymmetric radiative forcing with a net cloud albedo effect of − 0.05 W m − 2.

The fact of the matter is that IPCC has relied in AR4 on models, which assume a strongly positive net feedback from clouds, while subsequent physical observations show that the primary impact of clouds with warming is increased albedo and higher SW reflection resulting in an overall negative cloud feedback.

I have now realised that the global albedo changes necessary and the changes in solar energy input to the oceans can be explained by the latitudinal shifts (beyond normal seasonal variation) of all the air circulation systems and in particular the net latitudinal positions of the three main cloud bands namely the two generated by the mid latitude jet streams plus the Inter Tropical Convergence Zone (ITCZ).

A drying of the atmosphere — that the researchers note — takes place in the subtropical subsidence zone (the 30 degrees latitude) but expands towards the 30 - 45 degrees latitude — Earth's Meditteranean climates, where their model suggests net cloud cover would actually decrease most (see dotted line in first image in this article, at top)-- most notably around 500 hPa (roughly translating to a height of around 5 kilometers of altitude in the troposphere) decreasing albedo and increasing solar heat absorption, therefore net climate warming.

However, the effect of waves depends on the wind, and the net result fro measured results for clear days very closely approximates the reflection of P polarized light from smooth water at high sun angles: the «classic» water albedo of 0.06 is a good approximation between 90 degrees and 25 degrees solar angles.

In the paper, the two main findings are said to be that: (1) the net local effect of the volatiles lost when trees are cut is cooling, and (2) that this volatiles effect is of similar magnitude to albedo and CO2 effects from deforestation.

And I think you hit the nail on the head with: «5) Once we scientifically - oriented Skeptics accept the reality of the Atmospheric «greenhouse effect» we are, IMHO, better positioned to question the much larger issues which are: a) HOW MUCH does CO2 contribute to that effect, b) HOW MUCH does human burning of fossil fuels and land use changes that reduce albedo affect warming, and, perhaps most important, c) Does the resultant enhanced CO2 level and higher mean temperature actually have a net benefit for humankind?»

Re # 5 As far as I understand it (drawing on my recollections of a lecture Hansen gave here at Yale a few weeks back), the actual net forcing associated with Milankovich cycles is relatively small, but it tends to trigger massive feedbacks (e.g. polar ice expanding, lowering albedo, cooling, expanding more) that «snowball» into a glacial period.

The «equilibrium state» can not absorb more LW since, by the definition of equilibrium, the net absorption is zero, and insolation (corrected for albedo) is still the same.

[23] Chapter 8 of AR5, referring to a seven model study, states that» There is no agreement on the sign of the temperature change induced by anthropogenic land - use change» and concludes that a net cooling of the surface — accounting for processes that are not limited to the albedo — is about as likely as not».