Shortwave irradiation

Figure 7-1. Schematic illustration of eight forms of radiant energy incident on an exposed leaf, including six that involve shortwave irradiation from the sun and contain the letter S and two that involve infrared (IR) radiation incident on the upper and the lower leaf surfaces. Also illustrated is the IR emitted by a leaf.

Certain plants, especially those exposed to intense shortwave irradiation, have vertical leaves, such as willow, many species of Eucalyptusand certain chaparral and desert shrubs. Over the course of a day, vertical leaves... 

Soil acts as an extremely important component in the energy balances of plants. For instance, shortwave irradiation can be reflected from the surface of the soil, it is the source of longwave radiation that can correspond to a temperature considerably different from that of the ambient air, and heat can be conducted to or from stems in the region of their contact with the soil. Also, considerable amounts of energy can be stored by the soil, in contrast to the case for most leaves. Although the soil surface can have large daily oscillations in temperature (e.g., Fig. 7-13), the soil temperature at moderate depths of 1 m can be extremely steady on a daily basis (variations less than 0.1°C) and fairly steady seasonally. 

D. If the net radiation balance averaged over the spine surface is due entirely to shortwave irradiation (i.e., IRabsocbed = IRemitted) and if the maximum shortwave irradiation measured perpendicular to the cylinder lateral surface is 100 W m-2, what is the mean T6 51116 to within 0.1°C Ignore spine heat conduction to the stem. 

Summer days in the boreal zone are long, the daily period of illumination increasing virtually to 24 h in the north. Radiation is a primary driving variable of earth surface-atmosphere energy exchange including evaporation. On a clear day, for an unpolluted atmosphere, shortwave irradiance at the earth s surface obtains a maximum of around 70-80% of the extraterrestrial value due to... 

As an example of the integrated effect of atmospheric radiation attenuation, for June-August 1997 at a relatively sunny aspen forest site in Northern Canada (53.7°N, 106.2°W ), the measured shortwave irradiance averaged 80% of the clear-sky value computed for an atmospheric transmissivity of 0.8 (T.A. Black, personal communication). 

FIGURE 4 (A) Relations between daily clear-sky shortwave irradiance at... 

Murcray, F. J A. Goldman, J. C. Landry, and T. M. Stephen, 02 Continuum A Possible Explanation for the Discrepancies between Measured and Modeled Shortwave Surface Irradiances, Geophys. Res. Lett., 24, 2315-2317 (1997). 

D. Given that net radiation is due entirely to absorbed shortwave radiation and that heat loss does not occur through evaporation or conduction to the stem, Equation 7.2 indicates that the absorbed solar irradiation must be balanced by convective heat loss (Eq. 7.15) ... 

Convection ceases at the tropopause level, and the temperature in the stratosphere and mesosphere is determined strictly by radiation balance. At altitudes above 20 km the absorption of solar ultraviolet radiation becomes increasingly important. The temperature peak at the stratopause has its origin in the absorption of near-ultraviolet radiation by stratospheric ozone. In fact, the existence of the ozone layer is in itself a consequence of the ultraviolet (UV) irradiation of the atmosphere. The enormous temperature increase in the thermosphere is due to the absorption of extremely shortwaved and thus energetic radiation coupled with the tenuity of the atmosphere, which prevents an effective removal of heat by thermal radiation. Instead, the heat must be carried downward by conduction toward denser layers of the atmosphere, where H20 and C02 are sufficiently abundant to permit the excess energy to be radiated into space. 

Transfer the Hank s/sperm solution on a watch glass or small plastic Petri dish, and UV-irradiate. Inactivated sperm should be stored on ice. Since individual sources vary in their output of UV irradiation, a time-course of irradiation should be performed. However, as a reference point, we find that irradiation for 5 min at a distance of 20 cm by our UV shortwave source produces inactivated sperm still able to fertilize. Shorter periods fail to inactivate and lead to diploid embryos, easily discemable by their longer tails. Longer periods highly reduced fertility. 

Colorless, nonluminescent substances, which show self-absorption in the shortwave UV region, can be visualized under a UV-lamp (X = 254 nm) by using TLC plates with a fluorescent indicator. On layers containing or impregnated with a fluorescent indicator, the emission is reduced in regions where UV active substances absorb the UV light with which they are irradiated. Such substances... 

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