Altitude Effects

The altitude effect is seen in Fig. 9.15. The 5lsO values in Swiss precipitation are lighter with higher altitudes. The gradient, or altitude effect, is — 0.26%o 5180/100m altitude. The altitude effect is observed in this case to be the same in the precipitation and in the derived surface and groundwaters. This effect is not masked by the seasonal temperature effect (Fig. 9.10). 

The altitude effect has to be established in each study area. Leontiadis et al. (1983) reported a value of —0.44%o/100m for the part of Greece that borders Bulgaria. 

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A nice control was tritium, found to be higher in wells with higher plain-recharge contributions, revealing shorter travel times, as compared to low tritium contents in wells with higher contributions of mountain recharge (longer travel times). 

The altitude effect is applied in an ever-growing number of studies as a tool to calculate the recharge altitude from the deuterium and d180 data of springs and wells. Hence, much interest lies in a study of Bortolami et al. (1978), who checked the accuracy of such calculations in a case study in the Italian Maritime Alps. They conducted the following measurements rID and 

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Hunter and Grant (1971) showed that the magnitude of the altitude effect on yield varied with season. In spring, yields were decreased by some 5% for every 30.5 m rise in altitude and in autumn by 1.8%. In summer, yield trends were non-significant or reversed, highest yields sometimes occurring at the higher altitudes. This result was related to the development of moisture stress at lower altitudes. 

A significant altitude effect will be shown by these illuminating compositions, especially those containing excess metal. The decreased atmospheric pressure - and therefore less oxygen - at higher altitudes will slow the burning rate as the excess fuel will not be consumed as efficiently. 

Figure 14 shows the altitude effect on the sampler flow rate. This test was performed in a vacuum chamber. The flow rate was monitored with a bubble tube which was mounted in the chamber and operated by remote control. Each data point is an average of 18 pieces of data three samplers and three flow rates which were monitored while both increasing and decreasing the vacuum. 

Some altitude effects on the operation of chromatographic instruments are anticipated. To achieve reproducible retention times for identifying compounds, mobile-phase flows need to be controlled so that they are independent of ambient pressure. Detectors may also respond to changes in pressure. For example, the electron capture detector is a concentration-sensitive sensor and exhibits diminished signal as the pressure decreases. Other detectors, such as the flame ionization detector, respond to the mass of the sample and are insensitive to altitude as long as the mass flow is controlled. 

The 10 min sums of erythemal solar irradiances measured simultaneously during ten months at two locations in the Czech Republic were analysed. The altitude effect is about 4 to 8% per 1000 m, the radiation amplification factor is about 1.1 and both numbers vary only slightly with solar zenith angle. The statistical model relating erythemal solar irradiance with total column ozone and solar zenith angle was developed. This model and the annual cycles of the mean and variability of total column ozone are used to estimate variability of annual and daily cycles of mean erythemal solar irradiance. 

The UV-ERY measurements made at two locations in the Czech Republic were analysed in [7]. The values of the altitude effect and the radiation amplification factor (RAF) and their dependence on SZA were assessed, and the statistical model relating UV-ERY with SZA and total ozone was developed. In this contribution, the main results obtained in that analysis are summarised (Sections 3, 4 and 5) and then the statistical model and the annual cycle of total ozone (Section 6) are used to estimate the... 

The altitude effect (Sec. 3) and the radiation amplification factor (Sec. 4) were derived from UV-ERY measurements made simultaneously at two locations in the Czech Republic. The value of RAF obtained from the present data agrees with previous studies of other authors. The value of the amplitude effect agrees with the value used by National Weather Service and EPA [10] but is lower than the values obtained by other authors [2, 9]. The statistical model relating UV-ERY irradiance with total ozone and solar zenith angle was developed (Sec. 5 Fig. 2). Although the information on the total ozone does not satisfactorily improves accuracy of the UV-ERY forecast (further variables should be incorporated into the model to improve its accuracy), the model may be used to estimate annual and daily cycles of sun-visible UV-ERY irradiance for various total ozone levels. The results obtained show variability of the model UV-ERY irradiance related to variability of total column ozone. Specifically, it is demonstrated that the UV-ERY irradiance may exceed the annual/daily normal-ozone maxima during non-negligible portion of the year/day (about 214 months/hours) if the total ozone... 

Blumthaler, M., Ambach, W., and Huber, M. (1993) Altitude effect of solar UV radiation dependent on albedo, turbidity, and solar elevation, Meteorol. Z, N.F. 2,116-120. 

A unique application of IR spectroscopy to expl technology is the measurement of auroral far IR emissions (Ref 43). In conjunction with the High Altitude Effects Simulation (HAES)... 

Gonfiantini R, Roche MA, Olivry JC, Fontes JC, Zuppi GM (2001) The altitude effect on the isotopic composition of tropical rains. Chem Geol 181 147-167... 

Gonhantini R, Stichler W, Rozanski K (1995) Standards and intercomparison materials distributed by the International Atomic Energy Agency for stable isotope measurments. In IAEA-TECDOC-825, Reference and intercomparison materials for stable isotopes of light elements. IAEA, Vienna, p. 13-29 Gonhantini R, Roche M-A, Olivry J-C, Fontes J-C, Zupi GM (2001) The altitude effect on the isotopic composition of tropical rains. Chem Geol 181 147-167... 

Delacasiniere A, Grenier JC, Cabot T, Wemeckfaga M (1993) Altitude Effect on the Clearness Index in the French Alps. Sol Energy 51 93-100... 

Altitude. Altitude can either increase or decrease toxicity. It has been suggested that these effects are related to the metabolism of toxicants rather than to physiological mechanisms involving the receptor system, but in most examples this has not been demonstrated clearly. Examples of altitude effects include the observations that at altitudes of > 5000 ft, the lethality of digitalis or strychnine to mice is decreased, whereas that of D-amphetamine is increased. 

Fig. 9.10 Monthly mean <5lsO values in precipitation and monthly mean air temperatures from 1971-1978 for Swiss stations. The value of January (1) is shown twice to complete the cycle. The d180 values are seen to covary with the temperature, reflecting a pronounced temperature effect of 0.35-0.5%o d180/°C. The measurements, carried out at three stations of different altitudes, revealed an altitude effect, precipitation at higher altitudes having isotopically lighter compositions. (From Siegenthaler and Oeschger, 1980.)...

They analyzed <5180 in weighted mean precipitation samples from different altitudes and defined an altitude effect of — 0.26%o/100m (Fig. 9.16). 

Fig. 9.15 Variations of mean <5180 as a function of altitude for Swiss precipitation ( ), groundwaters (x), and rivers (A)- The lines are parallel, all revealing an altitude effect of —0.26%o <5lsO/100m. (From Siegenthaler and Oeschger, 1980.)...

They analyzed groundwaters with known recharge altitudes and found the same altitude effect (Fig. 9.17). 

Fig. 9.17 Altitude effect, reflected in groundwater of known recharge areas, Nicaragua. An effect of —0.26%o c>180/100m is obtained, the same as observed for the regional precipitation (see Fig. 9.16). (From Payne and Yurtsever, 1974.)...

Fig. 9.18 Isotopic compositions, as a function of altitude, for precipitation samples collected in a summer month (April 1976) and a winter month (October 1974), Maritime Alps. The data were used to establish local altitude effect equations (see text). Winter and summer <5lsO values fall on separate lines, reflecting the difference in the origin of the precipitating air masses from the Atlantic and Mediterranean, respectively. (After Bortolami et al., 1978.)...

An altitude effect, caused by spring recharge in higher elevations. This would agree with the increased temperatures, indicating relatively deep circulation. 

Springs for which the recharge altitude could be deduced from field data were analyzed and an isotope-altitude graph was established, defining the local altitude effect (Fig. 9.26). 

The altitude of the area of recharge, relevant to the altitude effect, taken into account in stable isotope paleoclimate deductions (section 9.8). 

Answer 9.5 Calibration of the local isotopic altitude effect. Springs or shallow wells located (a) at different altitudes and (b) at the base of small ridges, to be sure they are recharged by local precipitation. One should exclude springs or wells located at faults, deep wells, or thermal waters—all of these may have remote recharge and therefore will not represent an identifiable recharge altitude. 

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