Warm periods

Figure 3-57 Power fail indicator/alert circuits (a) a 5V under-voltage indicator (b) an under-voltage indicator for any voltage (c) power-down signal derived from the input line (longest warming period).

Warming spikes appeared more than 20 times in the Greenland ice records. Within hundreds or thousands of years after the start of a warm period, the climate went into slow cooling followed by quick cooling over as short a time as a century. There would then begin another warming that could take only a few years. 

After a warm period, in the Pangea/Panthalassa arrangement of Earth about 210 My ago, the end-Triassic mass mortality caused the disappearance of mammal-like reptiles leaving place to the dinosaurs, the first angiosperms, and the first mammals. 

Jones 2001). According to sea level changes, the last Ice Age, centered at 18,000 years ago, was even colder than now (3-4 C) (Lamheck 2001). In contrast, the Medieval Warm Period was wanner than now (0.5 C), and both the Interglacial Period (130,000 y from now) and the Eocene Warm period (33-53 My from now) were even warmer (3-4 C) (Webb 1992). 

A side objective arised from the evidence of high background tropospheric ozone levels observed during the warm period of the year over Eastern Mediterannean. The study of the mechanisms maintaining the enhanced tropospheric ozone in the Aegean and interrelationships with the UV radiation field is hence also part of the project. 

When the same photolysis is carried out at — 70°C to get the meso-diepoxide 310, warming to room temperature affords 306. However, if a second irradiation at shorter wavelength is carried out during the warming period, a mixture containing only 307 and 308 is obtained. Based on these observations, Rigaudy et al.17S have proposed the mechanism in Scheme 5, suggesting that... 

These data were based on actual temperature measurements. Using proxy data, that is inferred from other data, it is clear that the earth s temperature has been fluctuating and that now we are in a warm period (Figure 15.2) [2-4],... 

Tollen s test The reagent should be freshly prepared by mixing two solutions (A and B). Solution A is a 10% aqueous AgNOs solution and solution B is a 10% aqueous NaOH solution. When the test is required, 1 ml of solution A and 1 ml of solution B are mixed, and the silver oxide thus formed is dissolved by dropwise addition of 10% aqueous NH4OH. To the clear solution, 10 drops of the compound to be tested are added. A silver mirror is indicative of the presence of an aldehyde. The reagent mixture (A + B) is to be prepared immediately prior to use otherwise, explosive silver fulminate will form. The silver mirror is usually deposited on the walls of the test tube either immediately or after a short warming period in a hot water bath. This is to be disposed of immediately with diluted HN03 (detection limit, 50 mg compounds tested, Q to C6). 

Two and four tenths grams of d-cts-dinitrobis (ethylene-diamine) cobalt (III) bromide (3.4 X 10-3 mol) is suspended in 35 ml. of water in a 100-ml. conical flask. Freshly precipitated silver chloride (6 g.) is added, the mixture heated to 50 to 60°, and the flask stoppered and shaken vigorously for 4 to 5 minutes. The mixture is kept at about 50 to 60° during this time by warming periodically. The mixture is filtered and the silver halide precipitate washed with 5 ml. of warm water. Four grams of potassium ethylenedia-... 

The annual trend of the relative moisture content over the greater part of the Black Sea shows its maximum values in the cold season of the year and the lowest values in the warm period. The humid subtropical areas of the eastern coast are characterized by a somewhat distinct regime here, the highest values are observed in the summer and the intra-annual variations are in-... 

The principal features of the vertical T,S structure of the Black Sea waters are shown in Fig. 3. The upper mixed layer (UML) of the Black Sea in the warm period of the year has a thickness less than 10 m (see Fig. 3a). At this time, it is underlain by the layer of the seasonal pycnocline (ther-mocline) this layer is also thin (10-20 m) but features high vertical gradients of temperature (0.2-0.3 °Cm 1) and, correspondingly, of water density... 

The absolute minimum of the water temperature in the Black Sea is usually encountered in the upper part of the main pycnocline and has values of 6.5-75 °C (see Fig. 3a). Only in severe winters is it located in the UML. The layer with a temperature lower than 8 °C is referred to as the cold intermediate layer (CIL) [2-4], In the warm period of the year, it is sandwiched between the seasonal and main pycnoclines of the Black Sea with a slight local decrease in the vertical density gradients (see Fig. 3a). Over the greater part of the area, at the end of the winter, the upper boundary of the CIL (the upper 8 °C isotherm) is exposed at the sea surface. At this time, the major part of the CIL is located inside the UML and only its lower part is related to the main pycnocline. Thus, in this period, the CIL provisionally becomes the cold surface layer. 

The rather northernly fauna of Pfezletice near Prague contains Mimomys savini and is the best indicator that decidedly warm periods also occurred here. Recently, I was able to show the presence of finds of distinctly Mediterranean avian species (spoonbill, Platalea white-headed duck , Oxyura) in this material. 

This continental glaciation happened seven times over the last 2.2 million years. Warm intervals, some of them hundreds of thousands of years long, stretched between these planetary deep-freezes. Geologists do not agree whether the ice will return or not. Even if the present day is in a warm period between glaciations, tens or hundreds of thousands of years may elapse before the next advance of the ice sheets. 

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