Latent heat flux

Sea Salts - Most of the Na and Cl in both Greenland and Antarctica is of marine origin [1,13,21]. Near the ocean, sea salts may also account for most of the Mg, K, Ca, and S042-. Concentrations of Na and Cl display a maximum in winter Greenland precipitation which is coincident with the minimum oxygen isotope delta values [1,13,18]. The seasonal maximum in sea salt concentrations may be due to increased storminess, over the ocean in winter or to an increased poleward latent heat flux during the polar night [13]. 

The combustion heat rate (latent heat flux of conversion gas) (W/m )... 

From the information about the mass flux of the conversion gas it is possible to calculate the latent heat flux of combustion contained in the conversion gases from the relationship... 

If this excess absorption by clouds is ultimately shown to be a real phenomenon, then an increased cloud formation and extent due to anthropogenic emissions may alter the radiative balance of the atmosphere not only through increased reflectance but also through increased absorption of solar radiation. Such an effect could impact atmospheric temperatures, their vertical distribution, and circulation, as well as surface wind speeds and the surface latent heat flux (Kiehl et al., 1995). Hence establishing if this is truly excess absorption, and if so, its origins, is a critical issue that remains to be resolved. 

The latent heat flux for dilute solutions is given by [34]... 

An appropriately chosen set of surface parameters can be related to specific physical processes. For example, it is not surprising that the area covered by vegetation drives the magnitude of the latent heat flux, or that morphometric parameters help to describe the roughness and turbulence characteristics over a particular urban surface. Therefore, the following three most important characteristics can be outlined (cf. Piringer and Joffre, 2005 [497], for a summary). 

Following Zhang and McPhaden (1995), the important contribution of latent heat fluxes increases with the increase in sea surface temperature (SST). This holds true for moderate ranges in the SST, the wind speed, and the humidity difference between the surface air and the saturation humidity observed at the sea surface of the North Atlantic. This means, however, that latent heat fluxes and associated fluctuations in air temperature should be roughly in... 

Zhang, G. J., McPhaden, M. J., 1995. The relationship between sea surface temperature and latent heat flux in the Equatorial Pacific. Journal of Climate, 8, 589-605. 

The calculation of the resistance coefficients can be accomplished in the frame of the Monin-Obukhov similarity theory (Monin and Yaglom, 1971). The genuine flux quantities are the friction velocity u and the scale functions 0 and referring to temperature and humidity. The turbulent momentum flux f, the sensible heat flux the mass flux from evaporation and condensation and the corresponding latent heat flux are... 

Drag Coefficients for Wind Stress and for the Sensible and Latent Heat Flux For the numerical simulations of the Baltic Sea circulation discussed here, the parameterization of Smith and Banke (1975)... 

In closed air circulation mode, no heat exchange between water and air is present. The relative humidity reaches nearly 100%, and the latent heat flux vanishes. The temperature in the air space of the facility quickly (approximately 1 minute) adjusts to the water temperature so that, in addition, the sensible heat flux is eliminated. Thus no net heat flux at the water surface is present and the bulk temperature is equal to the surface temperature (see Fig. 5). 

If the air space of the wind-wave flume is flushed with dry air (relative humidity approximately 75%), a latent heat flux is established through evaporation. The surface temperature drops a few tenth of a degree ( cool skin ) and skin-bulk temperature difference is forced across the thermal sublayer. 

Two conditions were realized in the wind wave facility in the first set of experiments the interface was clean, whereas in the second set a surfactant (Triton-X-100, concentration 3 ppm) was used. Image sequences of duration of 1 second (60 frames at 60 Hz) were recorded every 10 seconds for a time period of 50 minutes. This procedure was repeated at four different wind speeds. Using the controllable air ventilation system in the wind wave facility, the latent heat flux was switched on and off every 5 minutes. The net loss of heat at the water surface was determined by the rate of change of the overall water bulk temperature (Schimpf 2000). 

Fig. 7. Estimates of the skin-bulk temperature based on latent heat flux switching method and prediction of a fit assuming a surface renewal model...

Figure 9. Fluxes of methanol measured with a fast response PTR-MS instrument during hay harvesting at a field site in western Austria. The data shown are for methanol fluxes on the second day after hay cutting, and for periods when the prevailing wind was suitable. Methanol fluxes largely correlated with air temperature, declined sharply in the afternoon, and approached zero as the hay harvest began after 15 45. Also plotted are sensible heat flux (i.e. transfer of heat due to conduction and convection) and latent heat flux (i.e. heat loss due to evaporation of liquid water). Data redrawn from Ref. [45].

The incoming solar energy absorbed by the Earth is —44 units this is balanced by the net upward flux of infrared radiation of — 15 units, plus —6 unit loss by sensible heat conduction, and —23 unit loss by latent heat. The Earth emits — 115 units of infrared radiation to the atmosphere, whereas the atmosphere emits —170 units of infrared radiation, a net deficit of —55 units. Since the atmosphere absorbs —26 units of solar radiation, the net radiative loss from the atmosphere is —29 units this is made up for by the sensible and latent heat fluxes. The net radiative cooling of the atmosphere is thus balanced by the latent heat of condensation released in precipitation processes and by the convection and conduction of sensible heat from the surface. 

The early development process of cyclones is very important in the ECS and a definite fact is that the heat fluxes are transferred from ocean to atmosphere, in which the latent heat flux is not only more important than the sensible heat flux but is about 20 times that of the sensible heat flux. The heat fluxes transferred from ocean to atmosphere accelerate the instability of the atmosphere in the lower layer, which is one of the important causes leading to a cyclone developing in the ECS. 

The incoming energy to the system is dependent on the location of the road. The net energy supplied to the surface is divided into change in heat storage in the pavement structure, sensible heat flux and latent heat flux. 

Sensible heat flux = pCpCr T - T ir)U o = Hs Latent heat flux = LTpCEiqsea - qakWw = Hi Moisture flux = /OCfC sea - qairWw = E... 

It is obvious, then, that we must couple two models of atmosphere and ocean for prediction of seasonal time scale. Physically, these two models interact with each other in sucha way thatthe atmospheric model, uses SST predicted by the ocean model, which requires the surface wind stress, the net surface energy flux (i.e., the sum of sensible and latent heat fluxes), and the net influx of fresh water (i.e., precipitation minus evaporation). The atmospheric model requires information on surface energy exchange as well as the SST. 

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