The ocean and atmosphere interact through air-sea fluxes. These fluxes, or exchanges, are the most direct ocean climate indicator of how the ocean influences climate and weather and their extremes, and of how the atmosphere forces ocean variability. Momentum fluxes (wind stress) drive general ocean circulation, setting up the ocean gyres and current systems that can redistribute heat and properties within the ocean. Moisture fluxes (evaporation and precipitation) over the ocean are the source of water that supports life on the planet. Through the latent heat of evaporation, these moisture fluxes are linked to the air-sea fluxes of heat. Air-sea fluxes of heat are the primary mechanism by which the ocean influences the atmosphere.
By comparing fluxes based on direct observations to fluxes computed by models, the models can be improved to more accurately reflect actual conditions. This will allow better understanding of weather and climate, as well as improved forecasts. More accurate forecasts directly lead to a more informed society, able to anticipate and respond to climate and its impacts.
fluxes
Indium Corporation manufactures a complete line of TACFlux which includes no-clean, water-wash, and RMA-based fluxes. Its many uses include: rework and repair of various electronics assemblies and components, SMT component attach (including BGAs and flip-chips), BGA ball-attach, preform soldering, and virtually any application where a flux is required. Cycle times are not critical as TACFlux may sit for hours with no reflow degradation.
Indium Corporation offers a full line of competitive, state-of-the-art wave solder fluxes for electronics assembly. We are the first company to introduce halogen-free, Pb-free wave fluxes that perform as well as the more established halogen-containing tin-lead wave fluxes.
Epoxy fluxes are often used in no-clean SMT component attach applications. The solder bumps on wafer level CSP, micro BGA or BGA packages are dipped in epoxy fluxes, or the flux is applied to the substrate via a jetting process. The assembly is then reflowed, and the epoxy flux acts to both clean up the solder joints before reflow, and to reinforce the final joint from the cured polymer.
For each 30-m pixel included in the model, gross forest-related emissions and removals are estimated as the product of activity data and emission/removal factors. Net forest GHG flux is the sum of gross fluxes. Text and arrows in orange are portions of the removals methodology that are passed into the emissions methodology.
The redox cofactor nicotinamide adenine dinucleotide (NAD) plays a central role in metabolism and is a substrate for signaling enzymes including poly-ADP-ribose-polymerases (PARPs) and sirtuins. NAD concentration falls during aging, which has triggered intense interest in strategies to boost NAD levels. A limitation in understanding NAD metabolism has been reliance on concentration measurements. Here, we present isotope-tracer methods for NAD flux quantitation. In cell lines, NAD was made from nicotinamide and consumed largely by PARPs and sirtuins. In vivo, NAD was made from tryptophan selectively in the liver, which then excreted nicotinamide. NAD fluxes varied widely across tissues, with high flux in the small intestine and spleen and low flux in the skeletal muscle. Intravenous administration of nicotinamide riboside or mononucleotide delivered intact molecules to multiple tissues, but the same agents given orally were metabolized to nicotinamide in the liver. Thus, flux analysis can reveal tissue-specific NAD metabolism.
A new algorithm is applied to study water vapor fluxes in the troposphere using wind and moisture data from the European Centre for Medium-Range Weather Forecasts. The fluxes are divided into filamentary structures known as tropospheric rivers and what are termed here broad fields. The results show that the tropospheric rivers may carry essentially the total meridional transport observed in the extratropical atmosphere but may occupy only about 10% of the total longitudinal length at a given latitude. The transient fluxes in traditional studies do not catch the filamentary structures completely and may therefore underestimate the fraction of transport assigned to moving systems, as well as omitting the geographical concentration. The mean flow and eddy fluxes evaluated by the new algorithm are considered to be more physically realistic.
In Eqs. (7), it is customary to substitute (6) and treat the total flux over a time period, such as a month or more, as the sums of contributions by the time and zonal mean motions, transient perturbations, and stationary eddies. There are a number of ways of performing these resolutions of atmospheric fluxes, and the physical processes involved are included in some of the discussions (e.g., Starr and White 1952a,b).
To try to assess the magnitude of the river fluxes in the troposphere, we introduce a new approach in the present study by dividing the fluxes into river fluxes and the residual called the broad fluxes.
The rivers in the Southern Hemisphere were related to long-wave circulations. Figure 4 gives the geopotential height at 1000 hPa for the same day as Figs. 2 and 3. The rivers were in or slightly ahead of the surface troughs. The equatorward and poleward flows on the west and east sides of the troughs, respectively, form filamentary wind shears or convergence lines over the surface. Since the equatorward flows are usually cold and dry and the poleward flows are warm and moist, the sharp contrasts of temperature and humidity may occur along the convergence lines in the lower troposphere, and the poleward moisture fluxes are stronger than the equatorward fluxes even if the opposite mass fluxes have the same intensity. The poleward fluxes formed by large-scale processes on the warm side of temperature fronts may be further intensified and narrowed by meso- and small-scale convective activities along the convergence lines. Formation of the rivers may be independent of the genesis and development of baroclinic cyclones, though the cyclonic activity may have an effect on the development of rivers. We have discussed the effect on rapidly developing cyclones elsewhere (Zhu and Newell 1994). The rivers are obviously the transient circulation systems, which have an important contribution to water vapor transport.
When the baroclinic waves are destabilized, the cold and dry air behind a polar front fills up the low levels of a new cyclone. As a result, the river is pushed to the eastern edge of the cyclone and may be intensified as the wind speed increases in disturbance development. This may be seen by comparing Figs. 2a and 4. The rivers over South America, to the south of Australia, and over the northeastern Pacific were all located to the east of a cyclone. The cyclone usually moves toward the head of the river, where water vapor convergence is maximum; this point has been treated elsewhere (Zhu and Newell 1994). To the west of the cyclone centers, the flows produced equatorward moisture fluxes, as shown in Fig. 3b, in the northeast Pacific, near Japan, and near the United Kingdom. As pointed out by Zhu and Newell (1994), the extratropical cyclones over the oceans often move toward the heads of rivers. Thus, the storm tracks are located in the river tracks.
Apart from the baroclinic cyclones generated in the extratropical regions, tropical cyclones may also increase the poleward fluxes of water vapor. Figure 2a shows that Typhoon Orchid near the southeast coast of Japan produced a large poleward flux. Typhoon Pat, to the northeast, which was disappearing and merging into Orchid, produced a slightly weaker flux peak to the northeast. Since the cores of tropical cyclones are warm and moist, the maximum fluxes are closer to the storm centers, if compared with the rivers near the extratropical cyclones.
The feature of river fluxes shown in Figs. 2 and 3 is a fairly common occurrence. Figure 5 illustrates thevariation between January and July of the two types of flux, using gridpoint data from three 1-month periods. The river fluxes in January 1992, 1995, and 1996 (Fig. 5a) show concentrations in the central North and South Atlantic, the eastern North Pacific, and the southeast Pacific, while in July 1991, 1994, and 1995 (Fig. 5c), they also cover the Indian Ocean and Southeast Asia monsoon region. A comparison of Figs. 1b and 5c, which cover the same 3 months of July data, shows that the transient rivers formulation includes the strong convergence over western India, which is assigned to the mean fluxes in the traditional approach (Fig. 1b). Figures 5a and 5c also show a general correspondence with the storm tracks, particularly over the oceans in winter. The broad fluxes (Figs. 5b for January and 5d for July), by the selection of Eq. (11), do not show filamentary structure. Interestingly, the broad fluxes (Fig. 5d) show convergence in the Bay of Bengal in the same region that the river fluxes show divergence. This interaction is being further investigated with a series of daily maps. Figure 6 summarizes the meridional fluxes by the two types over a period of 3 years, from June 1991 to May 1992 and June 1994 to May 1996, and includes the zonal scale as in Fig. 3c. Except in the tropical regions, the seasonal and annual mean poleward transports were accomplished by rivers covering only 10% of the longitude. The relative contribution of rivers was slightly larger in the summer hemisphere than in the winter hemisphere. There is substantial interhemispheric transport in the Tropics. 2ff7e9595c
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