Com - Untitled. We now have accrued enough background knowledge to talk knowingly about global circulation patterns of the air, which produces both the systematic and the air mass-controlled winds on the surface and aloft and which accounts for rain- or snow-producing precipitation. First, however, we show one general feature of hemispheric air distribution. The tropopause (boundary between troposphere and stratosphere) becomes progressively higher from the poles to the equator, as seen in this diagram.
This simply means that cold air at the equator, being heavier, sinks down and brings with it the vertical pressure gradient. Air, as we have seen, moves under pressure gradients, and modified by the Coriolis Force and friction, so as to rise, move laterally, and fall depending on its density. In our real, rotating world the Coriolist Force and other factors cause the single cell to break up into three cells, each with its characteristic circulation pattern. Let examine what happens at each cell zone. Miss Terre. Com - data: NOAA NCEP-NCAR CDAS-1 MONTHLY Intrinsic PressureLevel u. MONTHLY Intrinsic PressureLevel u u u u zonal wind from NOAA NCEP-NCAR CDAS-1: Climate Data Assimilation System I; NCEP-NCAR Reanalysis Project.
Independent Variables (Grids) Pressure grid: /P (mb) ordered [ (200)] :grid Time grid: /T (months since 1960-01-01) ordered (Jan 1982) to (Mar 2012) by 1.0 N= 363 pts :grid Longitude grid: /X (degree_east) ordered (165E) to (167.5E) N= 2 pts :grid Latitude grid: /Y (degree_north) ordered [ (22.5S)] :grid Other Info bufferwordsize calendar standard center US Weather Service - National Met. Datatype realarraytype grib_name gribfield GRIBgridcode gribleveltype gribNumBits gribparam gribvariable PDS_TimeRange pointwidth process 62 wave triangular, 28 layer Spectral model from "Medium Range Forecast" run PTVersion scale_max scale_min subcenter NCEP Ensemble Products units m /s standard units* meter second-1 References Kalnay, E., M. Le changement climatique - Dossiers - La documentation Française. ScienceDirect - Encyclopedia of Quaternary.
Climate - Welcome | WCRP. Climate - Climat Accueil.
Recherche - PARCS Syntheses. The timing, dynamics, and cause of the Holocene Thermal Maximum in the Arctic Home A major goal of PARCS research is to understand the nature and consequences of warmth in the Arctic and its impact on the global climate system. Here we describe such a warming that occurred during the early to middle Holocene. We developed a network of sites with paleoenvironmental records derived from lake and marine sediment cores, glaciers, and other sources. These data are used to identify spatial-temporal patterns of warmth on time scales ranging from decades to millennia. For manageability, we chose to describe first the western Arctic (Kaufman et al. 2004). Our description and analysis of the eastern Arctic Holocene Thermal Maximum will be complete by late 2005. The Methods: A page dedicated to how we executed the synthesis described here. The Data: A page dedicated to the data used in this project.
A Concluding Page: We present our conslusions and provide links to other pages of interest. NOAA-mid-holo. Paleoclimatologists have long suspected that the "middle Holocene" or a period roughly from 7,000 to 5,000 years ago, was warmer than the present day. Terms like the Alti-thermal or Hypsi-thermal or Climatic Optimum have all been used to refer to this warm period that marked the middle of the current interglacial period. Today, however, we know that these terms are obsolete and that the truth of the Holocene is more complicated than originally believed.
What is most remarkable about the mid-Holocene is that we now have a good understanding of both the global patterns of temperature change during that period AND what caused them. It appears clear that changes in the Earth's orbit have operated slowly over thousands and millions of years to change the amount of solar radiation reaching each latitudinal band of the Earth during each month.
In summary, the mid-Holocene, roughly 6,000 years ago, was generally warmer than today, but only in summer and only in the northern hemisphere. CO2. IPCC. Palaeoclimate. Astronomical solutions for paleoclimates generates Earth's orbital parameters (eccentricity, tilt, climatic precession, and insolation) over a span of 50 million years in the past to 20 million years in the future.
One of my slow learning projects has to been to use the output from this program to create illustrations of orbital configurations at key climatic transitions, such as the Eemian interglacial. When graphed, data of orbital parameters often look like this: (Diagram redrawn from Wikipedia and IPCC 4th Assessment Report) For a scientist, this is useful, but not being a scientist I looked for a display that I would find inituitive and useful for explaining what I'm learning to others. I'm not going for precision, but rather, for an illustration that can show the change and show when some orbit parameters would have a collective warming or cooling influence. For example, the following contains my exaggeration of orbit eccentricity and tilt: jg.
Recherche - The Last Interglacial - An Analogue for the Future? Many of the current predictions for future climate and environmental impacts have been made on the basis of complex computer models of the Earth's systems. Though such models have been successful in many areas, and are improving in accuracy and fidelity with increasing computer power, they still carry large uncertainties and margins of error, especially the further into the future that models are run.
One way that such uncertainties might be reduced is by looking at the geological and fossil record for periods in Earth's history that were warmer than today and determine how the environment responded. This may allow us to better estimate the effects of climate change that could face us. Figure 1: Timeline of past 150,000 years.
In Europe, the early part of the Eemian, as it was in transition from the preceding glacial stage, was distinguished by treeless, grassy plains that eventually gave way to pine forests and then extensive oak and hazel forests as the climate warmed. EarthOrbitAndClimate. Recherche - Climate. Bright Stars Temecula Valley (home) Requests and comments can be made at brightstarsWildomar, Vostok Graph) Revision 3/12/2011: Added x-y markers for any data point. Click a datapoint to display the marker; click again to hide it. You can use these markers to compare y-axis values of data that do not fit within a field of view. E.g., you can zoom in on Holocene (past 10kyr) values while having a y-value of an Eemian (115-125kya) datapoint displayed.
In case the new version has bugs, the previous version is still available here: climate_old Revision 2/17/11: Horizontal markers indicating the vertical axis values can be pinned: Mouse over a scale marker to show the horizontal bar, then click the bar or the label. Revision 1/21/11: The graphs can be displayed right to left (palaeoclimate standard) or left to right (common expectation).
Revision 12/29/10: Extended range of viewer to 740 kya to show show full extend of EPICA temperatures.