Associations of weather fronts with pig reproduction and mortality

ABSTRACTFarmers and practising veterinarians have long suspected the impact of weather fronts on production and animal health. A common impression is that sows will farrow earlier in connection with a cold front. There might be a correlation between daily mortality and the occurrence of a strong atmospheric front. Population-based quantitative studies on weather fronts’ effects on animal health and production are very sparse in the scientific literature. In this study, the associations between the weather fronts and daily farrowing incidence, the pregnancy length and the daily death incidence were analysed. The results show that cold front increased the odds of more than daily six farrowings on the day of the front (with at least 3°C cooling OR: 4.79, 95%CI: 1.08-21.21, p=0.039). On the day of the front, with at least 3°C temperature change both the cold and the warm front increased the odds of the farrowing on the day ≥ 118th day of the gestation (OR: 3.10, 95%CI: 1.04-9.30, p=0.43 and OR: 4.39, 95%CI: 1.73-11.15, p=0.002, respectively). On the day after the day of front, the odds of farrowing on the ≤ 113th day of gestation are increased, if the temperature decrease was at least 2°C the OR: 2.30 (95%CI: 1.04-5.06, p=0.039). On the day after the warm front with at least 1°C temperature increase the odds of more than daily three deaths is increased (OR: 5.44, 95%CI: 1.23-24.05, p=0.025).

P6146Atmospheric front patterns and acute cardiovascular diseases, a new perspective in the cardiovascular threat of global climate change

Background There is substantial evidence that the health threat of global climate change is real and it could be a medical emergency. The impact of climate change on health is mediated through atmospheric parameters which are direct environmental stressors on the human body and have a potential cardiovascular (CV) morbidity and mortality effect. Acute cardiovascular diseases (ACVDs) are already major public health issues and in the future unfavourable atmospheric situations, such as increasingly volatile fronts and their negative effects can further increase this problem. Despite evidence about the importance of different atmospheric parameters on health outcomes, there have been few results for atmospheric front patterns' CV effects. Weather fronts are the most complex atmospheric phenomena therefore these atmospheric parameters might have the greatest influence on ACVDs. Purpose We aimed to explore the effects of atmospheric front patterns on ACVDs. Methods A time series Poisson-regression analysis was used to analyse 6499 ACVD hospital admissions, during a five-year period (2009–2013), in light of front patterns. Covariates were three-day (target day and the two previous days) front sequence patterns comprised of the five major front types (no front, warm front, occluded front, cold front, stationary front). Relative risk (RR) estimates for front effects were adjusted for seasonality. The relationship on all ACVDs combined and separately on patient groups by major CV risk factors (hypertension, hyperlipidaemia, diabetes, previous CV diseases) was examined. Results We found that in general, front patterns containing warm front days had a detrimental effect. A warm front, when followed by two days with no fronts present, increased RR by 46% (CI: 4–89%, p=0,015). Cold fronts however were protective. A no front – cold front – occluded front pattern corresponded to a 28% (CI: 8–49%, p=0,037) decrease in RR, with this pattern being present in 1.1% of all days of the study period. Out of the group specific results an occluded front, following days with no fronts present, showed to have the largest effect on hyperlipidaemic patients, increasing RR by 144% (CI: 51–295%, p<0.001). Conclusions This work provides both independent evidence of front patterns' CV effects and a novel tool to investigate and help the understanding of complex associations between atmospheric fronts and ACVDs. The importance of our findings is growing in the context that extreme atmospheric conditions and changes are likely to become more common in the future as a result of climate change. Medical meteorology may open up a new horizon and become an important field of preventive cardiology in the future. In conclusion, a better understanding of atmospheric front effects is of particular importance in order to help identify possible targets for future prevention strategies.

Vertical propagation acoustic-gravity waves from atmospheric fronts into the upper atmosphere

Using experimental observations of atmospheric pressure variations on the Earth’s surface recorded with a network of 4 microbarographs located in the Moscow region during the passage of an atmospheric front, empirical approximations of oscillations of atmospheric pressure field were constructed. The obtained approximating functions were used as the lower boundary condition for the numerical simulation of acoustic-gravity wave propagation to the upper atmosphere from the source in the lower troposphere. Estimates of the amplitude of temperature disturbances in the upper atmosphere caused by iacoustic gravity waves from the atmospheric front are given. The obtained estimates for the temperature disturbance amplitude take values around 170 K. The amplitude of temperature disturbances in the upper atmosphere, caused by background variations of pressure on the Earth's surface, is estimated at 4-5 K.

Propagation to the upper atmosphere of acoustic-gravity waves from atmospheric fronts in the Moscow region

The paper uses experimental data of pressure variations on the Earth's surface during the passage of an atmospheric front recorded by a network of four microbarographs in the Moscow region. Applying these experimental data, empirical approximations of atmospheric pressure field oscillations are suggested. The obtained approximating surface pressure functions are used as the lower boundary condition for simulating the vertical propagation of acoustic-gravity waves from a source in the lower troposphere. Estimates of the amplitude of temperature disturbances in the upper atmosphere caused by acoustic-gravity waves from a propagating atmospheric front are obtained. For the amplitude of wave temperature disturbances, values of about 200 K are obtained. The amplitude of temperature disturbances in the upper atmosphere caused by background pressure fluctuations on the Earth's surface is estimated at 4–5 K.

Propagation to the upper atmosphere of acoustic-gravity waves from atmospheric fronts in the Moscow region

Experimental data of pressure variations on the Earth’s surface during the passage of an atmospheric front recorded on a network of 4 microbarographs in the Moscow region is used. Applying this experimental data, empirical approximations of atmospheric pressure field oscillations are suggested. The obtained approximating surface pressure functions are used as the lower boundary condition for simulating the vertical propagation of acoustic-gravity waves from a source in the lower troposphere. Estimates of the amplitude of temperature disturbances in the upper atmosphere caused by acoustic-gravity waves from a propagating atmospheric front are obtained. For the amplitude of wave temperature disturbances, values of about 200 K is obtained. The amplitude of temperature disturbances in the upper atmosphere caused by background pressure fluctuations on the Earth’s surface is estimated as 4–5 K.