Seasonal variabilities

Temperature swings following frontal passages are common in North America and Eurasia, but are rare in the tropics, where differences in cloudiness and precipitation arise from seasonal variability in thermal forcing. Poleward from the tropical regions, extratropical cyclones transform latitudinal temperature gradients into kinetic energy. 

Thiels GM, Murray CN, Vanderborght OLJ, et al. 1984. The effect of water acidity and seasonal variability on the distribution of241 Am in the freshwater snail Lymnaea stagnalis L. Health Phys 47(3) 485-487. 

Comparison of day-time to night-time exposure or identification of seasonal variability in exposure ... 

These have been ascribed to seasonal variability in organic inputs through rhizodeposition, microbial death and residue inputs and/or seasonal variability in soil microbial activity and thus metabolism of the... 

Fig. 2.11 Surface phytoplankton maps [kmol/m3] of overall temporal mean (left) and twodimensional time series (Hovmoller diagrams) showing the zonal mean seasonal variability.

Average Values. A major issue is how to cope with the normal variation in the composition of raw materials. The directive defines an average value as the value which best represents the amount of the nutrient which a given food contains and reflects allowances for seasonal variability, patterns of consumption and other factors which may cause the actual value to vary . 

Winner, R.W., H.A. Owen, and M.V. Moore. 1990. Seasonal variability on the sensitivity of freshwater lentic communities to a chronic copper stress. Aquat. Toxicol. 17 75-92. 

And finally, additional research is needed on mercury accumulation and detoxification in comparatively pristine ecosystems. Key uncertainties in understanding the process of mercury uptake in aquatic ecosystems, for example, include relations between water chemistry and respiratory uptake, quantitative estimates of intestinal tract methylation and depuration, and degree of seasonal variability in mercury speciation and methylation-demethylation processes (Post et al. 1996). 

Earthworm population Handsorting expulsion Indicates soil food web functioning spatially and seasonally variable time-consuming Blair et aL (1996)... 

An increase has also been observed in the LAS concentration in the aqueous phase during the cold season, due to reduced microbial activity [3,18,23]. Therefore the flow of LAS towards the coastal zone will be strongly influenced by the seasonal variable as confirmed by the values obtained by Takada et al. [3], who found that for the Tamagawa estuary the flow of LAS was five times higher in winter than in summer. However, in long-term monitoring [6,31,32], the variations detected are principally a function of tidal influence and of the time of day, or the day of the week, when the LAS is introduced into the system [6,33],... 

T.S. Bianchi, C. Rolff, B. Widbom and R. Elmgren, Phytoplankton pigments in Baltic Sea ses-ton and sediments seasonal variability, fluxes and transformations. Estuar. Coast. Shelf Sci. 55 (2002) 369-383. 

At sea level, Pj is approximately 1 atm, but exhibits some temporal and spatial variability. For example, the annual mean pressure in the northern hemisphere is 0.969 atm and in the southern hemisphere is 0.974 atm, with monthly averages varying by as much as 0.0001 atm, i.e., about 1 mbar (1 atm = 1013.25 mbar). These fluctuations are caused by spatial and temporal variations in atmospheric temperature and water vapor content associated with weather, and seasonal and longer-term climate shifts. Pj is also affected by diurnal atmospheric tides, and it decreases with increasing altitude above sea level. Some gases, such CO2 and O2, exhibit seasonal variability that is caused in part by seasonal variability in plant and animal activity (see Figures 25.4 and 6.7). 

Another attempt to compare cardiorespiratory deaths with photo-chemical-oxidant pollution was carried out by Mills, who compared seasonally adjusted nursing-home deaths in Los Angeles with measures of photochemical-oxidant pollution. He found a suggestive positive association between photochemical-oxidant concentration and excess deaths when pollution rose above 390 ng/m (0.2 ppm). Although heat and seasonal variability were considered, the statistical analyses used make it questionable whether their effect could be suppressed. 

The water supply in both watersheds is primarily from rainfall, surface runoff, and springs that are entirely recharged by rainfall. This means that between late May and early September the watersheds receive too much water resulting in terrain instabilities, erosion, and flooding. After September there is continuous drying until late May with only the occasional occurrences of rainstorms. The historic rainfall records are of limited duration and apart from the extreme seasonal variability, it was not possible to show any evidence of changes in the rainfall pattern over the past 10 years [14]. 

Bayona, J. M., M. Casellas, P. Fernandez, A. M. Solanas, and J. Albaiges, Sources and Seasonal Variability of Mutagenic Agents in the Barcelona City Aerosol, Chemosphere, 29, 441-450 (1994). 

Loubet B, Milford C, Hill PW, Tang YS, Cellier P, Sutton MA (2002) Seasonal variability of apoplastic NH4+ and pH in an intensively managed grassland. Plant Soil 238 97-110... 

Mijic Z, Stojic A, Perisic M, Rajsic S, Tasic M, Radenkovic M, Joksic J (2010) Seasonal variability and source apportionment of metals in the atmospheric deposition in Belgrade. Atmos Environ 44(30) 3630-3637... 

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