First results are presented of 18 months' experience with a microwave profiler that has been in operation in an unattended mode. Profiles of temperature and water vapor were retrieved without bias by a statistical regression method that was more accurate as opposed to a neural network approach, in particular for water vapor. Cloud liquid water was estimated by a neural network. The accuracy of the retrieved profiles estimated against quasisimultaneous radiosonde measurements are of comparable quality to that of the retrievals of ground-based Fourier transform infrared (FTIR) measurements. For temperature, the accuracy is about 0.6 K near the surface and less or equal to 1.6 K up to 7 km in summer and 4 km in winter. For water vapor, the corresponding values are 0.2-0.3 g m Ϫ3 near the surface and 0.8-1.0 g m Ϫ3 from 1-to 2-km altitude. The vertical resolution, however, is worse than that of FTIR measurements.Two case studies-a 1-week anticyclonic situation and 1 day with a cold front passage-demonstrate the capacity of microwave radiometry to sense the thermodynamic structure of the lower troposphere up to 3-4 km quasi-continuously with reasonable accuracy and height resolution, interrupted only during precipitation events. The diurnal course of temperature and humidity as well as the weakening of the amplitudes and decay with altitude was traced up to 4 km. Considerable structure was found, too, in the liquid water profile during the passage of the cold front. The cloud base retrieved from the microwave data corresponded well with collocated ceilometer measurements.

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Temperature affects many life processes, but its effect might be expected to differ among eukaryotic organisms inhabiting similar environments. We reviewed literature on temperature thresholds of humans, livestock, poultry, agricultural crops, and sparse examples of fisheries. We found that preferable and harmful temperatures are similar for humans, cattle, pigs, poultry, fish, and agricultural crops. Preferable temperatures range from 17°C to 24°C. Stress temperature thresholds are lower when humidity is higher. However, extended exposure to temperatures above 25°C with high humidity can cause heat stress in many organisms. Short exposures to temperatures above 35°C with high humidity, or above 40°C with low humidity, can be lethal. Increases in exposure, frequency, and duration of stressful and lethal temperatures increase the physiological stress and bodily damage suffered by humans, livestock, poultry, fish, and agricultural crops.

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Based on two years of measurements with a time resolution of 1 min, some climatological findings on precipitable water vapor (PWV) and cloud liquid water (CLW) in central Europe are given. A weak diurnal cycle is apparent. The mean overall diurnal variation was about 0.15 cm in summer and 0.05 cm in winter, equivalent to 8% and 5%, respectively. The PWV increase starts in summer at about 0800 local time and has a maximum of about 0.02 cm h Ϫ1 between 1000 and 1500 local time, equivalent to about 1% PWV h Ϫ1 . There was, on average, no PWV variation during the night in winter. PWV decreased in winter during the morning with a maximum of 0.01 cm h Ϫ1 and increased in the afternoon with a maximum of 0.01 cm h Ϫ1 . Thus, the accuracy of the monthly means of PWV based on monitoring systems with low-time resolution (satellites, radiosondes) is only slightly affected by the diurnal course of PWV in central Europe.On average an increase in PWV and CLW was found in the 30-min interval before precipitation in summer. The PWV increase was, however, only about 0.1 cm or 5% of PWV within the last 2 h before rain. The corresponding CLW increase was 0.1 mm, which is considerable as precipitation was observed when CLW reached 0.3-0.4 mm.