Sentences with phrase «oxygen isotope o18»

The main panel 1 data is from stable oxygen isotope measurements from the shells of macroscopic marine organisms («fossil shells»), collected by Veizer et al (1999), as re-interpreted by Royer et al (2004).

The continental glaciations of the Pleistocene left signatures on the landscape in the form of glacial deposits and landforms; however, the best knowledge of the magnitude and timing of the various glacial and interglacial periods comes from oxygen isotope records in ocean sediments.

Looking at the isotopic record from the PETM, scientists see both carbon and oxygen isotope ratios spiking in exactly the way we expect to see in the Anthropocene record.

Global, cyclic, decadal, climate patterns can be traced over the past millennium in glacier fluctuations, oxygen isotope ratios in ice cores, sea surface temperatures, and historic observations.

A negative trend is also seen in oxygen isotope records in Greenland ice cores (NGRIP - members 2004), which implies that the proxy records from northern Sweden display a general feature of Holocene climate in the North Atlantic region, possibly linked to orbital forcing of summer insolation.

Carbon and oxygen isotope ratios both shift at the same boundary; the former shows disruption of the carbon cycle, while the latter shows an abrupt warming of about 6 degrees.

Paleo temperatures from oxygen isotope ratios from the greenland ice cores show that a temperature increase of 0.7 °C will not bring the current temperature up to the level of the Medieval Warm Period let alone the Roman optimum and the MInoan Warm period which were both warmer than the medieval warm period.

Schmidt, G.A., 1999: Forward modeling of carbonate proxy data from planktonic foraminifera using oxygen isotope tracers in a global ocean model.

Despite these successes in linking variations in greenhouse gas concentrations to climate change in the geologic past, the oxygen isotope palaeotemperature record from 600 Myr ago to the present displays notable intervals for which inferred temperatures and pCO2 levels are not correlated1.

Oxygen isotope and palaeotemperature records from six Greenland ice - core stations temperatures during the Medieval Warm Period (~ AD 800-1100) were about 1 °C warmer than those of the Current Warm Period.

In this study, we used oxygen isotope ratios, which is a commonly used palaeothermometer.

We use isotope data from Zachos et al. [4], which are improved over data used in our earlier study [5], and we improve our prescription for separating the effects of deep ocean temperature and ice volume in the oxygen isotope record as well as our prescription for relating deep ocean temperature to surface air temperature.

The oxygen isotope evolution of seawater: a critical review of a long - standing controversy and an improved geological water cycle model for the past 3.4 billion years

We use the rich climate history of the Cenozoic era in the oxygen isotope record of ocean sediments to explore the relation of climate change with sea level and atmospheric CO2, inferring climate sensitivity empirically.

The principal dataset we use is the temporal variation of the oxygen isotope ratio (δ18O relative to δ16O; figure 1a right - hand scale) in the shells of deep - ocean - dwelling microscopic shelled animals (foraminifera) in a near - global compilation of ocean sediment cores [4].

As shown in the graph below, cosmic - ray intensity (as measured by the radioactive carbon isotope C - 14) and terrestrial climate (as measured by the oxygen isotope O - 18) correlate in amazing detail over an interval of at least 3000 years (see graph below; the bottom graph is the central section, blown up to reveal detail)

Juillet - Leclerc, A., and G. Schmidt, 2001: A calibration of the oxygen isotope paleothermometer of coral aragonite from Porites.

Because of the rapid growth rate of the snails, which are a widespread invasive species in India, moisture - sensitive oxygen isotope ratios in growth bands in the animals» shells preserve week - to - week rainfall rates, the researchers found.

This proxy, known as the δ18O stable oxygen isotope ratio, varies in proportion to the ambient moisture.

Inter - and intra-annual stable carbon and oxygen isotope signals in response to drought in Mediterranean pines

The proxy works like this: Although water can form using either a light or a heavy oxygen isotope, snails more readily draw in water with oxygen - 16 than with its heavier counterpart, oxygen - 18.

Prior to this, persistent warmth occurred from 1970 to 1975, a prominent anomaly that has been noted before (Schwerdtfeger 1976; Mosley - Thompson et al. 1991) and is consistent with positive anomalies of atmospheric mass over the Antarctic (Swanson and Trenberth 1981), and with positive oxygen isotope anomalies in West Antarctic ice cores (Mosley - Thompson et al. 1991).

In order to complete my analysis, I divided the beetles into five marine oxygen isotope intevals, as Elias did in his paper.

There is complexity in the path of the water vapor to the location, but the distance the water vapor travels is very important to the heavy oxygen isotope.

The Taylor ice core from Antarctica has about half the oxygen isotope range that those in Greenland do.

HS12 uses the oxygen isotope record in ocean sediments Zachos et al. (2008) to estimate past changes of sea level and ocean temperature, and thus obtain a largely empirical estimate of climate sensitivity.

135: It has been suggested that the 100 ka cycle in oxygen isotope data is due to changes in orbital inclination relative to the invariable plane (perpendicular to the solar system's angular momentum).

Uses a time series of hydrographic and stable oxygen isotope (δ18O) measurements collected at a near - coastal site in Marguerite Bay to quantify the prevalence of meteoric freshwater (glacial melt plus precipitation) separately from sea ice melt

Stable oxygen isotope ratios contained in the shell can be used to infer past water temperatures.

A study by Thomas, Dennis et al 2009 [8] derived a high resolution temperature proxy record from oxygen isotope ratios from the ice core.

This result emphasizes the nonstationary character of the oxygen isotope time series.

The correlation between atmospheric CO2 concentrations and global temperatures (I assume the global temperature readings are through Oxygen isotope analysis, but I am not sure how the CO2 readings were determined).

Mondo, I'm sorry my comment related explicitly to the oxygen isotope, O - 18, as a proxy for temperature and not tree rings.

http://www.agu.org/pubs/crossref/2002/2000PA000571.shtml On the 1470 - year pacing of Dansgaard - Oeschger warm events The oxygen isotope record from the Greenland Ice Sheet Project 2 (GISP2) ice core was reanalyzed in the frequency and time domains.

Preliminary results of oxygen isotope analysis of tree rings suggests anomalously low values during the 11th Century, perhaps indicating large - scale changes in circulation.

Core PS2138 - 2: MIS 6 and MIS 5 (5e) have mainly been identified by oxygen isotope stratigraphy, paleomagnetostratigraphy, and the occurrence of benthic foraminifera species Pullenia bulloides (P.b.)(Supplementary Fig. 5) 58, 67, 68.

The stratigraphic framework and related age models of the four sediment cores used in this study, are based on oxygen isotope stratigraphy, 10Be stratigraphy, paleomagnetostratigraphy, biostratigraphy, lithostratigraphy, and / or magnetic susceptibility records (Supplementary Figs. 2 — 5).

The three lines are: (1) the beginning: the Khirthar transgression and the onset of neritic carbonate accumulation in the Bartonian Age (preceding onset of the Middle Eocene climatic optimum [MECO]-RRB-; (2) the midlife change (Bartonian - Priabonian transition): the shift from carbonate - rich to carbonate - poor, higher - nutrient environments under estuarine circulation, causing widespread dysaerobia culminating in opaline silicas; and (3) the Eocene - Oligocene = Priabonian - Rupelian boundary and glaciation during oxygen isotope event Oi - 1, with return of improved ventilation in neritic environments and resumption of carbonate accumulation.

Matthiessen, J. & Knies, J. Dinoflagellate cyst evidence for warm interglacial conditions at the northern Barents Sea margin during marine oxygen isotope stage 5.

The fact that the Little Ice Age (about A.D. 1500 to 1900) stands out as a significant climatic event in the oxygen isotope and electrical conductivity records confirms the worldwide character of this event.

Another standards paper: Kim, Sang - Tae; O'Neil, James R.; Hillaire - Marcel, Claude; Mucci, Alfonso (2007) Oxygen isotope fractionation between synthetic aragonite and water: Influence of temperature and Mg2 + concentration» Geochimica et Cosmochimica Acta 71 (19) 4704 - 4715

The team then compared the oxygen isotope ratio for each year's wet season from 1990 to 2010 with a cyclone activity index of the average accumulated energy expended, based on factors such as number of cyclones, cyclone strength, size and time on storm track.

Another methodological classic: James R. O'Neil, Robert N. Clayton, and Toshiko K. Mayeda (1969) «Oxygen Isotope Fractionation in Divalent Metal Carbonates» J. Chem.

Rainfall from cyclones contains relatively little heavy oxygen so analysing the oxygen isotope ratio of calcite in stalagmites can reveal the extent of cyclone activity.

Calcareous nannofossils from approximately the past 7000 yr of the Holocene and from oxygen isotope stage 5 are present at 39 analyzed sites in the central Arctic Ocean.

The temperature is measured by the the oxygen isotope ratio, which we recently learned is the temperature of the leaves, and the leaves tend to keep a constant temperature.

The group highlighted the added value of measuring paired coral strontium / calcium ratios (Sr / Ca) and oxygen isotope ratios (δ18O), two key proxies for sea surface temperature that are often referred to as paleothermometers (δ18O also reflects sea surface salinity).

For decades, scientists studying climate change have measured the oxygen isotope ratio in tree - ring cellulose to determine the ambient temperature and relative humidity of past climates.

The key indicator is the «heavy» oxygen isotope δ18O.

Like the data used right through 0.02 to 66 My, the Freidrich et al collection comprises stable oxygen isotope ratios from the shells of tiny bottom - dwelling, deep - water marine organisms (benthic foraminifera).