Jun 30, 2007
Driest Year on Record in Los Angeles and Surroundings
This was the driest rain season ever in downtown Los Angeles and at many other locations in southwestern California. The 2006-2007 rain season, which began on July 1 2006 and ended on June 30 2007 is officially the driest ever in downtown Los Angeles since records began 130 years ago in 1877. Only 3.21 inches of rain fell during the season....nearly one foot or 11.93 inches below the normal for the season...which is 15.14 inches. Rainfall totaled only 21% of normal.
Rainfall was below normal in every month of this past season...with not one month receiving rainfall totaling one inch or greater. It is the first season since records began in 1877 not to have a single month during which one inch or more of rain was recorded. ironically, it follows just two years after the second wettest year on record (2004/05).
Why the dryness. The jet stream shifted north this year reflecting what appears to be a regime change underway in the Pacific Decadal Oscillation. Bill Patzert, a Jet Propulsion Laboratory scientist who researches the ocean’s role in climate variations noted stationary high pressure has pushed the moisture-bringing jet stream to the north, which has also allowed moist air to linger over Texas, he said. In California, he said, the drought situation resembles the 1950s and ‘60s rather than the unusually wet ‘80s and ‘90s, and it’s not going away.
“I think last year, unfortunately, people should plan on that as a preview of coming attractions, because there are no big patterns in the Pacific that are rainmakers,” he said. “There’s no El Nino galloping over the horizon to save us here.”
If indeed the Pacific regime change is taking place, expect more troublesome dry years in the southwest but much more snow in the Pacific Northwest and western Canada, where Whistler Mountain in British Columbia (near Vancouver) set a new snow record this season, with snowfall better than 40% above the normal.
Jun 27, 2007
Four Winters of Urban Heat Island Data from Barrow, Alaska (USA)
The Idso’s reviewed the 2007 paper by Hinkel and Nelson entitled “Anthropogenic heat island at Barrow, Alaska, during winter: 2001-2005” in the Journal of Geophysical Research. The authors report that since 2001 for the village of Barrow, Alaska (71.3°N, 156.5°W) - which has a population of approximately 4500 people - screen-level air temperatures have been recorded at hourly intervals by 68 data loggers that were distributed “to form an approximate grid pattern over the 150-square km study area” in and around the village.
On the basis of rural and urban group temperature averages for the period 1 December to 31 March of four consecutive winters, Hinkel and Nelson determined that the spatially-averaged temperature of the urban area was about 2°C warmer than that of the rural area, and that it was not uncommon for the daily magnitude of the urban heat island to exceed 4°C. In fact, they report that on some days the magnitude of the urban heat island exceeded 6°C, and that values in excess of 8°C were even recorded, while noting that the warmest individual site temperatures were “consistently observed in the urban core area.”
When attempting to measure a background global temperature increase that is believed to have been less than 1°C over the past century (which represents a warming on the order of 0.1°C per decade), it has to be appreciated just how difficult that task is when the presence of a mere 4500 people can create a winter heat island that may be two orders of magnitude greater than the signal being sought. Clearly, there is no way that temperature measurements made within the range of influence of even a small village can be adjusted to the degree of accuracy that is needed to reveal the true magnitude of the pristine rural temperature change. The only data of any value to this endeavor must be obtained from areas upon which there has been no historical human encroachment.
See story here.
Jun 27, 2007
A Review Of Vegetation–Atmosphere Interactions And Their Influences On Mesoscale Phenomena
By Roger Pielke Sr. Climate Science Blog
There is an excellent review paper (McPherson 2007) that provides further documentation of the first-order role of land surface processes within the climate system.
Among the conclusions, Dr. McPherson writes,
“The transformation of regional vegetation coverage to different land uses, especially the substitution of native forest with cropland, can result in local or regional climate changes as significant as those ascribed to the enhancement of atmospheric greenhouse gases by humans. Hence, it is important that scientists help policymakers put into perspective the consequences of various sources of weather modification.”
This important role of vegetation as a component of the climate system was recognized, for example, by the 2005 National Research Council Report titled Radiative Forcing of Climate Change: Expanding the Concept and Addressing Uncertainties , but was not appropriately reported on in the 2007 IPCC WG1 Report (i.e. see Chapter 8 and Chapter 9). Dr. McPherson has provided a very effective peer reviewed publication that documents an important climate change issue that the IPCC inadequately communicated to policymakers.
Read full weblog here
Jun 19, 2007
Comment on the Nature Weblog By Kevin Trenberth Entitled “Predictions of Climate”
Roger Pielke Sr. Climate Science Weblog
There is a remarkable weblog on Nature from an unexpected source that supports these views. The weblog is presented by one of the Lead Authors of Chapter 3 the IPCC WG1 report [Kevin Trenberth] and is in direct conflict with statements that climate science is settled. The Trenberth weblog reads:
I have often seen references to predictions of future climate by the Intergovernmental Panel on Climate Change (IPCC), presumably through the IPCC assessments (the various chapters in the recently completed Working Group I Fourth Assessment report ican be accessed through this listing). In fact, since the last report it is also often stated that the science is settled or done and now is the time for action.
In fact there are no predictions by IPCC at all. And there never have been. The IPCC instead proffers “what if” projections of future climate that correspond to certain emissions scenarios. There are a number of assumptions that go into these emissions scenarios. They are intended to cover a range of possible self consistent “story lines” that then provide decision makers with information about which paths might be more desirable. But they do not consider many things like the recovery of the ozone layer, for instance, or observed trends in forcing agents. There is no estimate, even probabilistically, as to the likelihood of any emissions scenario and no best guess.
Even if there were, the projections are based on model results that provide differences of the future climate relative to that today. None of the models used by IPCC are initialized to the observed state and none of the climate states in the models correspond even remotely to the current observed climate. In particular, the state of the oceans, sea ice, and soil moisture has no relationship to the observed state at any recent time in any of the IPCC models. There is neither an El Niño sequence nor any Pacific Decadal Oscillation that replicates the recent past; yet these are critical modes of variability that affect Pacific rim countries and beyond. The Atlantic Multidecadal Oscillation, that may depend on the thermohaline circulation and thus ocean currents in the Atlantic, is not set up to match today’s state, but it is a critical component of the Atlantic hurricanes and it undoubtedly affects forecasts for the next decade from Brazil to Europe. Moreover, the starting climate state in several of the models may depart significantly from the real climate owing to model errors. I postulate that regional climate change is impossible to deal with properly unless the models are initialized.
For Roger’s full weblog and comments see full weblog here.
Jun 18, 2007
Local Scientist Calls Global Warming Theory ‘Hooey’
The Capital Times
Reid Bryson, known as the father of scientific climatology, considers global warming a bunch of hooey. The UW-Madison professor emeritus, who stands against the scientific consensus on this issue, is referred to as a global warming skeptic. But he is not skeptical that global warming exists, he is just doubtful that humans are the cause of it. There is no question the earth has been warming. It is coming out of the “Little Ice Age,” he said in an interview this week. “However, there is no credible evidence that it is due to mankind and carbon dioxide. We’ve been coming out of a Little Ice Age for 300 years. We have not been making very much carbon dioxide for 300 years. It’s been warming up for a long time,” Bryson said. The Little Ice Age was driven by volcanic activity. That settled down so it is getting warmer, he said.
Humans are polluting the air and adding carbon dioxide to the atmosphere, but the effect is tiny, Bryson said. “It’s like there is an elephant charging in and you worry about the fact that there is a fly sitting on its head. It’s just a total misplacement of emphasis,” he said. “It really isn’t science because there’s no really good scientific evidence.” Just because almost all of the scientific community believes in man-made global warming proves absolutely nothing, Bryson said. “Consensus doesn’t prove anything, in science or anywhere else, except in democracy, maybe.”
See full story here.