Observed Temperature Trends

Shine, K. P., R. S. Freckleton, and P. M. de F. Forster, Comment on Climate Forcing by Stratospheric Ozone Depletion Calculated from Observed Temperature Trends, by Zhong et al. Geophys. Res. Lett., 25, 663-664 (1998). 

Shine, K.P., R.S. Frcckleton and P.M. de F.Forster. Comment on Climate forcing by stratospheric ozone depletion calculated from observed temperature trends , Geophys.Res.lMt., 25. 663-664.1998. 

In recent years it has been recognized that dynamic factors contribute much to observed temperature trends. For instance, in 1995 a marked similarity was observed between the spatial distributions of the SAT field and NAM fluctuations for the last 30 years, with a clear increase in the NAM index. The increasing trend of the index was accompanied by mild winters, changes in the spatial distribution of precipitation in Europe, and ozone layer depletion in the latitudinal belt >40°N. Similar data are available for the Southern Hemisphere. The main conclusion is that along with the ENSO event, both NAM and SAM are the leading factors in global atmospheric variability. In this connection, attention should be focused on the problem of the 30-year trend of NAM toward its increase, the more so that after 1995 the index lowered. It is still not clear whether this trend is a part of long-term oscillations. 

Using the spectroscopic technique previously described, Didenko et al., investigated the collapse temperature for rare gases in organic solvents (octanol and dodecane) with Cr(CO)6 as the spectroscopic probe [58]. They observed a trend in temperature consistent with that predicted based on differences in thermal... 

The wall temperature maps shown in Fig. 28 are intended to show the qualitative trends and patterns of wall temperature when conduction is or is not included in the tube wall. The temperatures on the tube wall could be calculated using the wall functions, since the wall heat flux was specified as a boundary condition and the accuracy of the values obtained will depend on their validity, which is related to the y+ values for the various solid surfaces. For the range of conditions in these simulations, we get y+ x 13-14. This is somewhat low for the k- model. The values of Tw are in line with industrially observed temperatures, but should not be taken as precise. 

In principle two similar crucibles containing respectively a sample of the alloy under investigation and an inert reference specimen are cooled (or heated) together in a furnace. By means of conveniently inserted thermocouples it is possible to follow (1) the continuous reference temperature trend of the reference specimen, (2) the temperature trend of the specimen under examination and (3) the temperature difference (A 7 ) between the two. If, at a certain temperature, there is a change in the structure of the sample (that is, if a boundary line in the corresponding phase diagram is crossed), a variation in the slope of the temperature vs. time curve is recorded. As a consequence the A7 vs. time curve (or vs. temperature) shows a deviation from the baseline. The temperatures at which such deviations are observed are used to build the phase diagram. 

In (b) typical trends of temperature vs. time are presented T0 is the controlled furnace temperature trend, 7 R is the T trend of the inert reference specimen, Ts is the trend observed for a sample undergoing some transformation. The corresponding differential curve (AT vs. time (or vs. temperature)) is shown in (c). 

The interaction of adsorbed reactants (phenol and methanol adsorbed separately and coadsorbed) and possible reaction products of phenol methylation with the Cul-xCoxFe204 system has been studied at temperatures between lOOoC and 350oC and probed by in situ FTIR spectroscopy. The spectra of adsorbed methanol, phenol and methylated products on catalyst surface, at lOOoC, did not possess much changes compared to the spectra of pure components that indicated the molecular adsorption of species on catalyst surface. The remarkable changes in the spectra occur, above 100°C due to the chemisorption of substrates, were observed and correlated with the observed reaction trend. 

Cons Perfectly isothermal conditions are not observed for simple prototypes such as described in Fig. 10.6, especially for highly exothermic reactions like partial or total oxidation, with observed temperature profiles and local hot spots (see results for the Selox reaction). However, these limitations do not prevent the observation of significant trends when large libraries are tested under various operating conditions. Commercial, improved systems adapted to the requirement of academia are now available on the market... 

In recent years, neuron models have been successfully used they are more stable than traditional climate models. For instance, Pasini et al. (2006) considered an application of the neural network for climate modeling. The study was carried out into the temperature trend on regional and global scales for the last 140 years. It showed that the model based on the neural network reproduces with high accuracy the non-linear effects observed in temperature variations over the northern Atlantic. 

Recently close attention has been given to assessment of climate in Siberia and the Far East as regions adjacent to the Arctic. Flere a 0.5°-0.9°C increase of temperature in the last decade was observed, the trends of average temperatures increasing from north to south. Precipitation was redistributed, with an increase in winter and a negligible decrease in some regions in summer. For instance, in the Amur River basin over the last 30 years precipitation in the cold period of the year increased by 35%, and annual precipitation increased by 12.3%. 

For the He/MeONO system, the temperature dependence of Pn for He was determined [119. An 18% decrease in over a 31 K increase in temperature was observed. This trend is similar to that observed previously for MIC [122] and can be explained by considering the size of the vibrational partition function of MeONO which increases by 19% over the 31 K temperature interval studied. Previous studies of collisional energy transfer in MeONO have shown that the vibrational degrees of freedom of the colliders is important. Thus, an inert gas such as helium, which has only translational degrees of freedom, would be expected to show a decrease in collision efficiency relative to MeONO on itself with increasing temperature. 

The data in Table 13.3 show that the onset temperature of reaction for the three minerals becomes higher as the relative content of C becomes lower. As evident from the third column in Table 13.3, this trend is supported by the calculated temperature of maximum solubility. The second column reflects the experimentally observed temperature where the solubility is significant enough that the acid-base reaction starts. Thus, the numbers in the second column should be slightly lower than those in the third column, but they should be in the same range. The exception is C2 S, where the calculated is lower than the experimentally observed value for the onset of reaction. This anomaly may simply be because the measurements started at room temperature, and if they had been done from 0°C, one would have obtained a temperature closer to the theoretical calculations. 

Figure 4 shows that the PCO2 and temperature trends in computed and observed values of ki are similar. Computed values are below the experimental values as expected, implying a ki value some ten to twenty times ki. This qualitative and quantitative agreement between theory and experiment gives further support for our mechanistic model. 

The details of oscillation patterns, especially for chaotic oscillations, are often very sensitive to changes in the catalyst sample caused, for example, by variations between catalyst batches or differing pretreatment conditions. However, it is usually possible to observe clear trends in the frequency and oscillation amplitude with the variation of particular reaction parameters. For instance, increasing reaction temperature normally leads to increased frequency and decreased amplitude of the oscillations if other parameters... 

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