The paper reports measurements of the water relations of a barley crop (cv. Proctor) and a winter wheat crop (cv. Maris Huntsman), grown on the same site at Sutton Bonington. Throughout the two growing seasons, days were chosen when hourly measurements could be made of leaf water potential, by means of a pressure chamber, and of stomatal resistance, by means of a diffusion porometer. Environmental factors, e.g. radiation, temperature, humidity, were recorded concurrently. Relationships between leaf water potential, stomatal resistance and environmental factors are explored and compared for the two cereals. In particular, as frequent measurements were made over two months, the influence of leaf age on responses to environmental factors can be examined. On selected days with bright sunshine and dry soil the response of both cereals to water stress is analysed with particular reference to the control of evaporation by stomatal closure
What are the consequences of climatic and human‐induced change on the water balance and ecological diversity of the Upper San Pedro River Basin (USPB), which spans the border between southeastern Arizona and northern Sonora, Mexico? What are the effects of such change at event, seasonal, interannual, and decadal timescales? The interdisciplinary Semi‐Arid Land Surface Atmosphere Program (SALSA) seeks an answer to these complex questions.
Abstract An evaporation model based on Lagrangian turbulent diffusion principles is developed and compared with simpler single‐ and dual‐source K ‐theory models of evaporation. The performance of the Lagrangian model is assessed against observations of total evaporation by an eddy‐correlation instrument and found to be satisfactory for a millet crop in west Africa. Three versions of existing simpler models containing K ‐theory descriptions of within‐canopy turbulence are described and their results also compared. The two K ‐theory models that explicitly take into acccount the soil source perform better than the single‐source Penman‐Monteith model. A Lagrangian analysis does not seem to be necessary for this kind of crop because the low source‐density profile of the crop, associated with a low leaf‐area index, caused the near‐field effect to be very small. The overall difference between the evaporation estimates of the dual‐source and Lagrangian models is therefore small. It is concluded that, for practical purposes, K ‐theory remains an adequate approximation of turbulent transport in sparse‐crop evaporation models. Significant anomalies in the surface heat fluxes, particularly those of sensible heat, accompanied the decrease in the sea ice concentration. Substantial atmospheric warming was simulated over and in the vicinity of areas in which leads were considered. In all but one experiment there were anomalous easterlies between about 40 and 60°S with westerly anomalies further to the south. The surface pressure at high latitudes appears to change in a consistent fashion with the fraction of open water, with the largest changes occurring in the Weddell and near the Ross Seas. Some of the feedbacks which may enhance the responses here, but which are not included in our model, are discussed.
Many northern Australian rivers have limited or non-existent dry season flow and rivers tend to dry to a series of pools, or waterholes, which become particularly important refugial habitat for aquatic biota during the periods between streamflow events. The present study developed techniques to identify in-stream waterholes across large and inaccessible areas of the Flinders and Gilbert catchments using Landsat imagery. Application of this technique to 400 scenes between 2003 and 2010 facilitated the identification of key waterhole refugia that are likely to persist during all years. Relationships for predicting total waterhole area from streamflow characteristics were produced for four river reaches. Using these relationships and streamflow predictions based upon climate data scaled using 15 global climate models, the potential impacts of future climate on waterhole persistence was assessed. Reductions in waterhole area of more than 60% were modelled in some years under drier scenarios and this represents a large reduction in available habitat for areas that already have limited in-stream refugia. Conversely, under wetter future climates the total area of waterholes increased. The approach developed here has applicability in other catchments, both in Australia and globally, and for assessing the impacts of changed flow resulting from water resource development.
Abstract Phenol (hydroxybenzene) is a commercially important derivative of benzene. It is the primary feedstock for the production of epoxy resins and polycarbonates, phenolic resins and molding compounds, caprolactam, aniline, and other chemical derivatives. More than 95% of the phenol consumed is produced by the cumene peroxidation process. Phenol is a white, crystalline mass at room temperature. Its freezing point is 40.91°C. It is a protoplasmic poison that is corrosive to living tissue and is readily absorbed through the skin. Phenol’s consumption growth rate is based primarily on its use in engineering plastics such as bisphenol A, polycarbonates, polyetherimide and poly(phenylene oxide), and epoxy resins for the electronics industry. Due to the nature of its end markets, phenol consumption is highly cyclic. Future production processes for phenol will be affected by the disparity in growth rate between phenol and its coproduct, acetone.
'/%3e%3c/defs%3e%3cpath fill='%23012169' d='M0 0h10080v5040H0z'/%3e%3cpath stroke='%23fff' stroke-width='.6' d='m0 0 6 3m0-3L0 3' clip-path='url(%23b)' transform='scale(840)'/%3e%3cpath stroke='%23e4002b' stroke-width='.4' d='m0 0 6 3m0-3L0 3' clip-path='url(%23c)' transform='scale(840)'/%3e%3cpath stroke='%23fff' stroke-width='840' d='M2520 0v2520M0 1260h5040'/%3e%3cpath stroke='%23e4002b' stroke-width='504' d='M2520 0v2520M0 1260h5040'/%3e%3cg fill='%23fff'%3e%3cuse xlink:href='%23d' x='2520' y='3780'/%3e%3cuse xlink:href='%23a' x='7560' y='4200'/%3e%3cuse xlink:href='%23a' x='6300' y='2205'/%3e%3cuse xlink:href='%23a' x='7560' y='840'/%3e%3cuse xlink:href='%23a' x='8680' y='1869'/%3e%3cuse xlink:href='%23e' x='8064' y='2730'/%3e%3c/g%3e%3c/svg%3e)
'%3e%3cpath fill='%23012169' d='M0 0v30h60V0z'/%3e%3cpath stroke='%23fff' stroke-width='6' d='m0 0 60 30m0-30L0 30'/%3e%3cpath stroke='%23C8102E' stroke-width='4' d='m0 0 60 30m0-30L0 30' clip-path='url(%23b)'/%3e%3cpath stroke='%23fff' stroke-width='10' d='M30 0v30M0 15h60'/%3e%3cpath stroke='%23C8102E' stroke-width='6' d='M30 0v30M0 15h60'/%3e%3c/g%3e%3c/svg%3e)