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The dependence of the large-scale structure of oceanographic fields on short-term variations in atmospheric forcing (AF) at the ocean surface has been studied. Estimates of this dependence were obtained by comparing the results of two numerical experiments with the NEMO model in the ORCA1 configuration used as a computational core in the data assimilation system at the Hydrometeorological Center of Russia. The experiments similar in all other respects differed only in the discreteness of the AF data: 3–24 hours in the main experiment and 1 month in the experiment with time-averaged AF. Large-scale characteristics were compared: kinetic energy averaged over large regions, Atlantic Meridional Overturning Circulation, meridional heat transport, mixed layer depth, and sea ice volume. It has been shown that neglecting high-frequency AF variability can significantly distort the long-term evolution of oceanographic fields reproduced by ocean models and thereby affect the quality of model forecasts. [ABSTRACT FROM AUTHOR]

In the present work, the variations in Total Electron Content (TEC) induced by changes in the ionizing radiation of the Sun, which are related to the rotation period (about 27 days), were investigated. This study was based on a 30-year period. The relative deviations in the TEC and F10.7 values were used in the data analysis. The use of this modification aimed to eliminate the stationary diurnal, seasonal, and solar course of the TEC over the course of the long-term variations in solar activity, preserving the variations within a time scale of 27 days and less. As a result, the values of the linear regression coefficient between the relative deviations in the two considered quantities from the median (quiet conditions) for one rotation period were obtained. Depending on the general level of solar activity, the season, and the latitude, this coefficient varied between 40% and 60%. The analysis showed that the minimum values were observed during high solar activity. The latitudinal distribution demonstrated an increase in the area of the Equatorial Ionization Anomaly (EIA) under the influence of the so-called "fountain effect". As a result, there was a seasonal variation and an increase in the winter months at mid and high latitudes and a decrease in the months of the minimum zenith angle of the Sun at low latitudes. A well-pronounced asymmetry in the equinox months was also obtained. The obtained results are the novelty of this study and can be used to improve empirical models for short-term TEC forecasting. [ABSTRACT FROM AUTHOR]

In the present work, the variations in Total Electron Content (TEC) induced by changes in the ionizing radiation of the Sun, which are related to the rotation period (about 27 days), were investigated. This study was based on a 30-year period. The relative deviations in the TEC and F10.7 values were used in the data analysis. The use of this modification aimed to eliminate the stationary diurnal, seasonal, and solar course of the TEC over the course of the long-term variations in solar activity, preserving the variations within a time scale of 27 days and less. As a result, the values of the linear regression coefficient between the relative deviations in the two considered quantities from the median (quiet conditions) for one rotation period were obtained. Depending on the general level of solar activity, the season, and the latitude, this coefficient varied between 40% and 60%. The analysis showed that the minimum values were observed during high solar activity. The latitudinal distribution demonstrated an increase in the area of the Equatorial Ionization Anomaly (EIA) under the influence of the so-called “fountain effect”. As a result, there was a seasonal variation and an increase in the winter months at mid and high latitudes and a decrease in the months of the minimum zenith angle of the Sun at low latitudes. A well-pronounced asymmetry in the equinox months was also obtained. The obtained results are the novelty of this study and can be used to improve empirical models for short-term TEC forecasting.

The aim of the research was to assess the impact of root exudates of two widely distributed plant species, monocot (couch grass) and dicot (dandelion) on the concentrations of 27 macro- and trace elements in the rhizosphere soil of the plants. A field trial was carried out to study short-term variations in the concentrations of the elements when the plants grew separately or in close proximity to each other in non-contaminated soil and in soil contaminated by RbCl. During daytime, total amount of C and N in the rhizosphere soil of both plant species was found to be constantly decreasing. Similar variations were also found for Mg, Al, V, Ga, and As. The concentrations of some other elements (Na, Se, La, and Ce) showed a maximum value in the middle of day. These variations might be due to changes in the soil temperature. Contamination of soil by RbCl negatively affected the concentrations of several elements in the rhizosphere soil of couch grass and dandelion. The impact was more marked when the plants grew far from each other. Soil contamination by RbCl led to a decrease in number of natural isolates in bulk soil. In the soils taken from roots, of the plants grown in the Rb-contaminated soil, number of the same isolates increased compared with that in bulk soil, but level of the increase was different in the rhizosphere soil of couch grass and dandelion. The variations depended on whether these plants grew close to each other or separately. [ABSTRACT FROM AUTHOR]

Care should be taken to minimize the adverse impact of differential code biases (DCBs) on global navigation satellite systems (GNSS)-derived ionospheric information determinations. For the sake of convenience, satellite and receiver DCB products provided by the International GNSS Service (IGS) are treated as constants over a period of 24 h (Li et al. (2014)). However, if DCB estimates show remarkable intra-day variability, the DCBs estimated as constants over 1-day period will partially account for ionospheric modeling error; in this case DCBs will be required to be estimated over shorter time period. Therefore, it is important to further gain insight into the short-term variation characteristics of receiver DCBs. In this contribution, the IGS combined global ionospheric maps and the German Aerospace Center (DLR)-provided satellite DCBs are used in the improved method to determine the multi-GNSS receiver DCBs with an hourly time resolution. The intra-day stability of the receiver DCBs is thereby analyzed in detail. Based on 1 month of data collected within the multi-GNSS experiment of the IGS, a good agreement within the receiver DCBs is found between the resulting receiver DCB estimates and multi-GNSS DCB products from the DLR at a level of 0.24 ns for GPS, 0.28 ns for GLONASS, 0.28 ns for BDS, and 0.30 ns for Galileo. Although most of the receiver DCBs are relatively stable over a 1-day period, large fluctuations (more than 9 ns between two consecutive hours) within the receiver DCBs can be found. We also demonstrate the impact of the significant short-term variations in receiver DCBs on the extraction of ionospheric total electron content (TEC), at a level of 12.96 TECu (TEC unit). Compared to daily receiver DCB estimates, the hourly DCB estimates obtained from this study can reflect the short-term variations of the DCB estimates more dedicatedly. The main conclusion is that preliminary analysis of characteristics of receiver DCB variations over short-term intervals should be finished prior to estimate daily multi-GNSS receiver DCB products. [ABSTRACT FROM AUTHOR]

The paper discusses the long-term variability of maximum (Tmax) and minimum (Tmin) air temperature variations, both occurring from one day to the next and over several consecutive days (3-4), in Krakow (Poland, Central Europe) from 1826 to 2015 (i.e., over a period of 190 years). The authors analyzed the seasonal variability of short-term variations in air temperature, looking at the most significant changes (±10 °C), as well as at their dynamics and trends over the analyzed multi-annual period. A clear decrease has been observed both in the values of short-term Tmax and Tmin variations and in the number of cases with their significant fluctuations. The decrease has been gradual, without clear abrupt changes to the overall trend. The greatest short-term variations in temperature were most frequent in the cooler half-year, being smaller and less frequent in the summer months. If the observed trend persists, in the upcoming years we can expect a further decrease in the dynamics of variations in thermal conditions, i.e., short-term variations in temperature may more frequently be small, i.e., ±0.1-4.0 °C. However, it is worth noting that Tmax more frequently increased from one day to the next and over several consecutive days, while Tmin more frequently decreased. The reasons for the analyzed changes remain unclear. It seems that natural factors, mainly including the advection of air masses, have a significant impact on short-term variations in air temperature, coupled with local factors, which have been strengthened by the human impact on the environment, including the urban heat island. [ABSTRACT FROM AUTHOR]

The use of long-term (slow variations) for modelling radio propagation behavior in indoor scenarios limits the validity of such models, as most of the environments induced fast variations overlapped with the slow ones. Real world data gathered at different locations in two bands within Fifth Generation FR1 spectrum, 3 GHz and 5 GHz, provide insight on the effect of such fast variations and on the distribution models that would be useful to complement the long term analysis with short term behavior in order to improve the design of such 5G microwave networks. Comparisons among short term performance taking into account both the frequency, the visibility conditions and the environment size, shape and furnishing are presented with the focus on modelling as accurate as possible the narrowband channel. The use of ΔBIC (describing the difference between Bayesian Information Criteria indexes of each fitting) complements and confirms the insight provided by direct inspection on traditional fitting plots. This parameter could be interesting for future network deployments. [ABSTRACT FROM AUTHOR]