![]() ![]() Spencer and Christy point out that the surface versus satellite temperature controversy will likely not die away soon. The satellite measurements provide the first observational evidence that the surface and deep layer temperatures can vary slightly differently (a couple of tenths of a degree) over a decade or so." "The physics in these models is not refined enough to do anything else. In addition, the GCM did not include the direct forcing on the atmosphere from this century's two largest volcanoes," noted Spencer. "It is well known that GCMs will produce atmospheric temperatures that vary in lock-step with the surface temperatures. While Hurrell and Trenberth attempt to account for possible differences between the surface and deep-layer measurements by forcing a computerized atmospheric general circulation model (GCM) with the observed sea-water temperatures, this methodology is likely flawed. This is most likely a well-known phenomenon in which the temperature in the deep atmosphere is not as strongly linked to the surface temperature as it is over land." "It is primarily over the oceans where they disagree by a couple of tenths of a degree C. "Over Northern Hemisphere land areas, where the best surface thermometer data exist, the satellites and thermometers agree almost perfectly", said Dr. The disagreement between satellites and surface-based thermometers, furthermore, is not geographically uniform. Even in these disputed intervals, we find excellent agreement between the two independent, direct atmospheric temperature measurements from balloons and satellites." ![]() Christy explained further, "In particular, we've examined these two `breaks' claimed by Hurrell and Trenberth. "In fact, balloon measurements of the temperature in the same regions of the atmosphere we measure from space are in excellent agreement with the satellite results." Dr. "There isn't a problem with the measurements that we can find," Spencer explained. Spencer, an atmospheric scientist at NASA. So their estimate of the late 1981 break is inconsistent with these observations," observed Dr. "During the first period, we had two separate satellites, operating simultaneously, and agreeing with each other to about 0.02 degrees C. The recent paper's conclusion is based on two apparent "breaks" in the satellite versus sea-water temperature record, one in late 1981 and the other in late 1991. This so-called "disagreement" between satellite and surface temperature measurements is not new.ĭespite the fact that Hurrell and Trenberth estimate of the temperature of the atmosphere through a simple linear regression model based only on the sea surface temperatures, and a global climate model simulation with the same sea surface temperatures but no stratospheric volcanic aerosols, while the MSU data actually measure the temperature of the free atmosphere, Hurrell and Trenberth conclude that the satellite data must be wrong. C/decade, in apparent disagreement with the satellites. ![]() In the latest (March 13, 1997) edition of Nature, two scientists, James Hurrell and Kevin Trenberth, report that sea-surface temperatures monitored by buoys and ships at various locations in the tropics show, for the same period as the satellite record, a warming trend of +0.12 deg. The lower tropospheric temperature trend has been calculated to be -0.04 degrees C/decade. John Christy (The University of Alabama in Huntsville) have used the Microwave Sounding Units (MSUs) flying aboard NOAA's TIROS-N weather satellites to construct a continuous record of lower tropospheric (from the surface to about 4 miles) temperatures since the first MSU was launched in late 1978. Spencer (NASA Marshall Space Flight Center) and Dr. And while these data are exceedingly precise, verified by multiple satellite observations, and balloon measurements taken in-situ, they reveal no discernable warming trend in the Earth's lower atmosphere over the last 18+ years.ĭr. Recently, much scientific debate has focused on the global temperature of the Earth's lower atmosphere as measured by orbiting satellites. ![]()
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