Snowmelt was measured on a daily basis for 17 days at the open site and 18 days at three Japanese cedar sites with canopy closure of 17.8% (cedar stand A), 5.2% (B) and 2.4% (C) in April. Measured daily snowmelt at each site was reproduced by heat-balance calculation with an accuracy of <±1 mm w.e. From 1st April to the date of snow disappearance net radiation accounted for 88.4, 43.0, 32.7 and 34.2% of total snowmelt energy at the open site, the cedar stands A, B and C, respectively. The ratio of sensible and latent heat to total snowmelt was 33.1–37.9 and 25.9–29.4%, respectively, at three cedar stands. The ratios of sensible and latent heat increased over time in accordance with the rise in temperature at all cedar sites. They became large on a daily basis when air temperature and/or wind speed were high. Wind speed is dependent on morphology around each site that also dictated snowmelt.

Biotypes of common cocklebur were identified, which were assumed to differ only with respect to sensitivity to MSMA. Water use of these biotypes when grown as isolated plants in a growth chamber was determined with stem flow gauges. The MSMA-tolerant biotype exhibited less whole-plant sap flow at media moisture levels above 17%. Furthermore, only in the tolerant biotype did sap flow differ between the upper and lower canopy; the upper canopy had greater sap flow. Field experiments were conducted to compare growth parameters, water use and competitive ability toward cotton of the MSMA-sensitive and -tolerant biotypes. Sensitive biotype plants were taller and had greater leaf area than those of the tolerant biotype; dry weight was equivalent. The tolerant biotype used less water and reduced seed cotton yield more than the sensitive biotype.

Thermodynamics of a seasonal supraglacial lake were examined based on field data from three summers. At maximum, the lake body consisted of an upper layer with thin ice on top, and a lower layer with slush, hard ice and sediment at the bottom. Sublimation from the upper ice surface averaged to 0.7 mm d−1, and melting in the ice interior averaged to 9.1 mm d−1 during summer. Albedo was on average 0.6 and light attenuation coefficient was ~1 m−1. Averaged over December and January, and over 3 different years, we found that the net solar heating was 137 W m−2, while the losses averaged to 62 W m−2 for the longwave radiation, 16 W m−2 for the sensible heat flux, 24 W m−2 for the latent heat flux and 3 W m−2 for the bottom flux. The depth scale is determined by the light attenuation distance and thermal diffusion coefficient, and the net liquid water volume ranged from 0.5 to 1.0 m in different years. The potential winter growth is more than summer melting, and thus the lake freezes up completely in winter in the present climate.

A well-designed environmental control system is the most efficient tool to ensure optimal production in livestock housing. In countries having a hot climate, such as Spain, the former comprises a large proportion of the capital invested in housing, and it deserves a thorough assessment. Most of the research carried out has been done in countries with a temperate climate and considering short hot periods, or even without them. The efficiency of the evaporative cooling system, which is commonly used in hot climate areas, depends upon the pad wetted surface area exposed to the passing air. Keeping the chosen inside temperature requires a definite cooled down of the outdoor air that is related to the ‘temperature tolerance’, i.e. the difference between inside and incoming air temperatures. The objective of this work was to establish the temperature tolerance when using the steady-state heat balance in commercial poultry housing. The heat balance estimates were imbalanced whenever the difference between indoor and outdoor temperature was less than 2°C. Substituting the exhaust air temperature for the indoor temperature in the expression that provides the heat drawn out through ventilation balanced the heat equation. The difference between inside and incoming air temperatures, temperature tolerance, has to be at least 2°C.

A heat balance model was combined with a food intake model and a metabolism model, to form a larger model which estimates a pig’s response to heat stress. The combined model was implemented as a computer program, and used to calibrate, test and validate parts of the heat balance model. Heat transfer modes considered were convection, radiation and evaporation of water at the skin, and heating and humidification of air by breathing. Sensitivity analysis revealed a large effect of air temperature, humidity and velocity on heat loss, especially in a hot environment. It also showed that wetting of the pig’s skin is the most effective means to alleviate heat stress. The calibration procedure confirmed that characteristics related to heat tolerance in pigs must be re-evaluated, due mainly to the changes brought about by genetic improvement (such as reduced backfat thickness). The model was challenged using two different data sets. Although simulated results varied in the same way as measured data, more research is needed to determine more precisely some of the parameters. Long-term predictions were more reliable than those for short (1-day) periods.