It is commonly known that children do not engage in a sufficient amount of physical activity. Weather conditions and day length may influence physical activity of children. Little is known about the relationship between physical activity and seasons. The purpose of this study was to investigate the relationships between weather conditions and physical activity in 6–12 year old children based on hip-worn Actigraph wGT3X–BT accelerometer data. The study sample consisted of 2015 subjects aged 6–12 years from the Health Oriented Pedagogical Project (HOPP) study carried out in Horten municipality and Akershus county, Norway. Six days of sedentary and moderate-to-vigorous physical activity data was gathered in January–June and September–October, 2015, presented as daily averages. The accelerometer-monitored physical activity of children grouped within nine schools was matched with regional weather conditions and assessed with the means of linear mixed models. Increased day length was associated with decreased sedentary behavior. Warmer temperature and dry weather were associated with increased moderate-to-vigorous physical activity after adjusting for age and sex. One-hour increase in daylight resulted in a decrease of sedentary time by, on average, 2 min (95% CI = (−2.577, −0.798)). For every 5 °C increase in temperature (range: −0.95 and 15.51 °C) and dry weather, average moderate-to vigorous physical activity increased by 72 and 67 min (males and females, respectively) (p < 0.001). Days with precipitation had, on average, 10 fewer minutes of moderate-to-vigorous physical activity compared with days without precipitation (95% CI = (−16.704, −3.259)). Higher temperatures and dry weather led to higher physical activity levels, seeing larger increases among boys than girls. A school-based physical activity intervention program should be adjusted regarding local weather conditions in line with the present findings.

Radio systems are affected by rainfall, and the attenuation increases significantly with rain rate and frequency. Above about 10 GHz rainfall must generally be considered for estimating expected link availability with sufficient attenuation margin included. Rain rate is a key factor, and depending on climate, it will dictate the possible path length and other factors such as antenna size, for the planned performance of a system that operates at higher frequencies than about 10 GHz. This paper presents results from an analysis of Norwegian tipping bucket rain gauge data from 1967 to 2013. It is found that the rain rate currently used by the Radiocommunication Sector of the International Telecommunication Union recommendation for attenuation prediction, R 0.01 -the rate exceeded for 0.01% of an average year-has actually increased in all parts of the country from where long-term data exist. Moreover, the year to year variability is significant. The increase may well be seen as a consequence of climate change. Such a change may cause higher attenuation effects than expected when radio links are designed following "normal" dimensioning procedures.

No abstract

Rainfall rate varies both temporarily and spatially. Radio systems, where rain attenuation causes outages, may take advantage of this effect to increase the radio link or satellite link availability using diversity techniques. In the Oslo region with Norwegian Meteorological Institute located at Blindern, there are 24 tipping bucket rain gauges within 50 km radius of the institute where each station has 5 years or more of simultaneous data periods with the station at the institute. The simultaneous data have been used to calculate spatial rain rate correlation and derive a prediction method based on separation distance and orientation with respect to dominating weather direction. Part of joint rain rate distribution was fitted to lognormal to find the measured correlation coefficients. In addition, an analysis of independent radiosonde data suggests that prevailing wind at 700 hPa or 850 hPa altitude (approximately 3000 m or 1500 m above sea level), conditioned thunderstorm index in the range of 15 to 20, may be used to identify the actual rainfall movement or dominant weather direction. Compared with current recommended method by the Radiocommunication Sector of International Telecommunication Union, the new method gives an improved site diversity prediction judged by site selection of minimum 20 GHz attenuation data measured in 2012 from Earth stations located at Nittedal and Kjeller separated by 23 km.

No abstract