CO2, Soot, Modeling and Climate Sensitivity

15 07 2009

Warming Caused by Soot, Not CO2

From the Resilient Earth

Submitted by Doug L. Hoffman on Wed, 07/15/2009 – 13:19

A new paper in Science reports that a careful study of satellite data show the assumed cooling effect of aerosols in the atmosphere to be significantly less than previously estimated. Unfortunately, the assumed greater cooling has been used in climate models for years. In such models, the global-mean warming is determined by the balance of the radiative forcings—warming by greenhouse gases balanced against cooling by aerosols. Since a greater cooling effect has been used in climate models, the result has been to credit CO2 with a larger warming effect than it really has.

This question is of great importance to climate modelers because they have to be able to simulate the effect of GHG warming in order to accurately predict future climate change. The amount of temperature increase set into a climate model for a doubling of atmospheric CO2 is called the model’s sensitivity. As Dr. David Evans explained in a recent paper: “Yes, every emitted molecule of carbon dioxide (CO2) causes some warming—but the crucial question is how much warming do the CO2 emissions cause? If atmospheric CO2 levels doubled, would the temperature rise by 0.1°, 1.0°, or by 10.0° C?”


Temperature sensitivity scenarios from IPCC AR4.

The absorption frequencies of CO2 are already saturated, meaning that the atmosphere already captures close to 100% of the radiation at those frequencies. Read the rest of this entry »


Comments : 209 Comments »

Categories : Carbon dioxide, modeling

Spy Sat Images of Arctic ice declassified

15 07 2009

From the “pictures actually do matter” department…NSIDC’s Mark Serreze is thrilled to get them

download

Recently declassified high-resolution satellite photos, such as this one from the Canadian Fram Strait, could provide scientists with more detailed information about Arctic sea ice melting.

from Science News

Hundreds of high-resolution satellite photos of the Arctic sea ice taken during the past 10 years should be immediately declassified and released to the scientific research community, the National Research Council reported on July 15. Shortly after, the United States Geological Survey made about a thousand of the images available to the public through the Global Fiducials Library.

“Most people from the scientific community are not aware that these images have been collected,” says Stephanie Pfirman, chair of the NRC committee that wrote the report. “They’ll be very excited to see these results.”

The photos could help scientists study the rapid changes taking place in the Arctic, the committee members say. Current research efforts that might benefit include studies of polar bear habitats, of the movement of ice floes and of the formation and evolution of melt ponds — bodies of water that form on ice sheets and accelerate their melting. Read the rest of this entry »


Comments : 36 Comments »

Categories : Arctic, sea ice

GISS: World’s airports continue to run warmer than ROW

15 07 2009

Guest post by John Goetz

AIRLNRAD1As noted in the previous post, GISS has released their monthly global temperature summary for June, 2009. This month’s whopping anomaly of 0.63C is once again much higher than that of RSS, UAH, and even NOAA, which is the source of the GISS temperature data. Not only is the anomaly higher than the other metrics, but it is trending in the opposite direction.

Temperature data from 1079 stations worldwide contributed to the analysis, 134 of them being located in the 50 US states. Data from essentially the same few stations have been used for the past twenty-four months. Many, many hundreds of stations that have historically been included in the record and still collect data today continue to be ignored by GISS in global temperature calculations.

Once again, the bulk of temperatures comprising the present-day worldwide GISS average come from airports – in this case 554 airports, according to the NOAA metadata from the V2 station inventory. In the US, the ratio of airports to total stations continues to run very high, with 121 out of the 134 reporting stations being located at airports.

Why worry about airports? Aside from recent posts on this site documenting problems with airport ASOS equipment in the US, WUWT has also documented a number of equipment siting problems, notably the typical close proximity of the equipment to a tarmac heat sink. Airports can introduce a mini-UHI effect where one would otherwise not be found.

The NOAA metadata is not entirely accurate, and several stations located at airports are not noted as such. Some examples include Londrina and Brasilia in Brazil, Ely / Yelland in Nevada, and Broome in Austrailia. Those stations were easy to find because they had “airport” (or some variant) in the station name. A check of coordinates using Google Earth confirmed the airport locations.

Let’s examine the metadata a little further, shall we? Read the rest of this entry »


Comments : 137 Comments »

Categories : UHI, climate data, weather_stations