Moisture source

If it is variable, set the outside air intake quantity to the winter value. Set the desired temperature up to a maximum, leaving the humidity setting alone. It will be appreciated that as the room temperature rises during the heating test the rh tends to fall. However, since the humidity setting remains unaltered the humidifying system will be called upon to operate until at one condition it is working at peak winter rate. Due to the faster characteristic of heaters, the rh will be found to fall but absolute moisture should be found to steadily rise. The duration of the test is normally about 3 h and final conditions should be held for half an hour to prove the moisture source. 

Fig. 13.5 Cumulative mercury vapour from PMA-treated soil in relation to elapsed days Soil in PMA pot 6 was autoclaved before addition of PMA others (PMA pots 7, 8, 9), containing unautoclaved treated soil, varied in initial moisture Source Reproduced with permission from the American Chemical Society [30]... 

Figure 11 Vostok temperature changes from present-day values back to 420 kyr BP, estimated either AT s(spat) (in red) by the conventional approach based on the 6D profile alone (Petit et al., 1999) accounting correctly for the oceanic correction (see text), or A7 s(inv) (in green) from the inverse method based on the use of deuterium excess to account for moisture source changes (source Vimeux et al, 2002).

Glacial interglacial changes in moisture sources for Greenland influences on the ice core record of climate. Science 261, 508-511. 

Weyhenmeyer C. E., Burns S. J., Waber H. N., Aesbach-Hertig W., Kipfer R., Loosli H. H., and Matter A. (2000) Cool glacial temperatures and changes in moisture source recorded in Oman groundwaters. Science 287, 842- 845. 

Equilibrium isotopic-fractionation factors for O and D during evaporation and condensation are temperature-dependent, but the main control on degree of fractionation of precipitation 0 and D from the source composition is the fraction of water extracted from an air mass before condensation of the precipitation of interest (e.g. Dansgaard 1964). This in turn is controlled primarily by the difference between the temperature at which condensation first begins for an air mass, and the temperature at which the precipitation of interest condenses. The first-condensation temperature in turn is tied closely to the ocean surface temperature by the high and more-or-less constant relative humidities over most ocean surfaces (Vimeux et al. 2001). Hence, and 5D of precipitation depend in part on the temperatures at all contributing moisture sources, and not just on the temperature at the site. 

The altitude effecf and the continental effecf (Rozanski et al. 1993) refer to the tendencies for and 5D of precipitation to become progressively lower towards continental interiors and higher elevations. The altitude effect includes important control by temperature. Both may reflect a stochastic tendency for air masses moving away from moisture sources to encounter conditions (frontal/convective) that cause moisture extraction and so isotopic fractionation for °0 and D H it is possible that modeling of and 5D of precipitation could involve stochastic treatments. As reviewed by Rozanski et al. (1993), the continentality depletion for 5 0 of precipitation reaches 8 per mil over 4500 km into Europe from the Atlantic coast. This continental effect is more pronounced in winter than in summer, perhaps because evapotranspiration returns most summertime precipitation to the atmosphere, whereas runoff is more important in wintertime. 

Different sources of evaporating water can have different isotopic compositions, and often different path lengths to a site producing different continentality. Changes in moisture source thus can affect and 5D of precipitation in the absence of a temperature change (e.g. Charles et al. 1994). 

FIG. 2. Flow diagram showing the successive steps (processes) involved in production of Zousoon. The numbers in parentheses are given as weight ratio relative to raw meat == 1000. The starch cell preparation may be varied from 0 to 40 (weight ratio) and has a proximate composition of 22.4% protein, 68.0% carbohydrate, 1.9% fat, 0.8% ash, and 7.5% moisture. Source Chang et at (1991). Reprinted with kind permission from Elsevier Science Ltd. 

Definition Land or areas (such as tidal flats or swamps) containing much soil moisture. Source ... 

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