Intra-seasonal oscfffations of radio refractive index during southwest monsoon over India

The study deals with the spatial and temporal variations of intra-seasonal oscillations in radio refractive index during southwest monsoon season over India and islands over Indian seas. Average daily radio refractive index data from 1 June to 30 September and that of the individual years for the period 1969-1986 were subjected to harmonic analysis to investigate the contributions of various periodicities in monsoon radio refractive index. The inter-annual variability of various intra-seasonal oscillations have been studied for each 5° latitudinal strip from 50 oN to 30° N with the help of variance explained by various frequency modes for different years. Variance explained by 30-60 day and 10-20 day modes were studied in relation to monsoon performance. The northward and eastward propagation of30.60 day mod~ was noticed. The 10.20 day mode and seasonal mode dominate at latitudinal belts 5°N.10oN and 25°N-30°N respectively. Between 10°N and 25°N, both 30-60 day and 10-20 day modes occur.

Features of Seasonal Sea Level Oscillations in the Russian Arctic Seas

Based on the analysis of long series of monthly mean sea level values from the database of the PSMSL and ESIMO portals, we obtained estimates of the mean and extreme amplitudes of seasonal oscillations. The mean amplitude of annual sea level oscillations in the White Sea is 7 cm, in the Barents Sea is 9–10 cm, in the Kara Sea, is 8–9 cm, in the Laptev Sea, is 10–11 cm, in the East Siberian and Chukchi seas is 13–14 cm. In the estuarine areas of seas, the amplitude of annual oscillations increases, and the semiannual, third-annual, and quarter-annual components appear in the sea level spectra. They are formed due to the asymmetry of the seasonal sea level variation with a sharp maximum during the flood period in June. Interannual changes in the amplitude of seasonal oscillations were identified and estimates of their extreme values were obtained. In some years, the amplitude of seasonal oscillations reaches 50 cm in the Yenisei Gulf and Gulf of Ob, 60 cm near the mouth of the Lena River, and 75 cm at the mouth of the Olenek River.

Seasonal variation in blood pressure recorded in routine primary care

Objective: Seasonal variations in blood pressure (BP) exist. There is limited information about important clinical factors associated with increased BP and the strength and amplitude of seasonal variation in primary care. Methods: This was a repeated cross-sectional observational study of routinely measured BPs in primary care using data from electronic medical records in the greater Toronto region, from January 2009 to June 2019. We used time-series models and mean monthly systolic BPs (SBPs) and diastolic BPs (DBPs) to estimate the strength and amplitude of seasonal oscillations, as well as their associations with patient characteristics. Results: 314,518 patients were included. Mean SBPs and DBPs were higher in winter than summer. There was strong or perfect seasonality for all characteristics studied, except for BMI less than 18.5 (underweight). Overall, the mean maximal amplitude of the oscillation was 1.51mmHg for SPB (95% CI 1.30mmHg to 1.72mmHg) and 0.59mmHg for DBP (95% CI 0.44mmHg to 0.74mmHg). Patients aged 81 years or older had larger SBP oscillations than younger patients aged 18 to 30 years; the difference was 1.20mmHg (95% CI 1.15mmHg to 1.66mmHg). Hypertension was also associated with greater oscillations, difference 0.53mmHg (95% CI 0.18mmHg to 0.88mmHg). There were no significant differences in SBP oscillations by other patient characteristics, and none for DBP. Conclusion: Strong seasonality was detected for almost all patient subgroups studied and was greatest for older patients and for those with hypertension. The variation in BP between summer and winter should be considered by clinicians when making BP treatment decisions.

Multiscale interactions between monsoon intra-seasonal oscillations and low pressure systems that produce heavy rainfall events of different spatial extents

The sub-seasonal and synoptic-scale variability of the Indian summer monsoon rainfall are controlled primarily by monsoon intra-seasonal oscillations (MISO) and low pressure systems (LPS), respectively. The positive and negative phases of MISO lead to alternate epochs of above-normal (active) and below-normal (break) spells of rainfall. LPSs are embedded within the different phases of MISO and are known to produce heavy precipitation events over central India. Whether the interaction with the MISO phases modulates the precipitation response of LPSs, and thereby the characteristics of extreme rainfall events (EREs) remains unaddressed in the available literature. In this study, we analyze the LPSs that produce EREs of various spatial extents viz., Small, Medium, and Large over central India from 1979 to 2012. We also compare them with the LPSs that pass through central India and do not give any ERE (LPS-noex). We find that thermodynamic characteristics of LPSs that trigger different spatial extents of EREs are similar. However, they show differences in their dynamic characteristics. The ERE producing LPSs are slower, moister and more intense than LPS-noex. The LPSs that lead to Medium and Large EREs tend to occur during the positive phase of MISO when an active monsoon trough is present over central India. On the other hand, LPS-noex and the LPSs that trigger Small EREs occur mainly during the neutral or negative phases of the MISO. The large-scale dynamic forcing, intensification of LPSs, and diabatic generation of low-level potential vorticity due to the presence of active monsoon trough help in the organization of convection and lead to Medium and Large EREs. On the other hand, the LPSs that form during the negative or neutral phases of MISO do not intensify much during their lifetime and trigger scattered convection, leading to EREs of small size.

Short Rotation Intensive Culture of Willow, Spent Mushroom Substrate and Ramial Chipped Wood for Bioremediation of a Contaminated Site Used for Land Farming Activities of a Former Petrochemical Plant

The aim of this study was to investigate the bioremediation impacts of willows grown in short rotation intensive culture (SRIC) and supplemented or not with spent mushroom substrate (SMS) and ramial chipped wood (RCW). Results did not show that SMS significantly improved either biomass production or phytoremediation efficiency. After the three growing seasons, RCW-amended S. miyabeana accumulated significantly more Zn in the shoots, and greater increases of some PAHs were found in the soil of RCW-amended plots than in the soil of the two other ground cover treatments’ plots. Significantly higher Cd concentrations were found in the shoots of cultivar ‘SX61’. The results suggest that ‘SX61’ have reduced the natural attenuation of C10-C50 that occurred in the unvegetated control plots. The presence of willows also tended to increase the total soil concentrations of PCBs. Furthermore, we found that many contaminant concentrations were subject to seasonal oscillations, showing average increases throughout the whole experimental site after a growing period, while showing significantly different variations, such as lesser increases or even decreases, after a dormant period. These observations suggest that contaminants may have leached or degraded faster in untreated conditions, and conversely to have mobilized towards trees through water flow driven by plant transpiration during growing seasons.

Can land subsidence be monitored with ambient seismic auto-correlations?

<p>Mexico City has been undergoing rapid subsidence for more than 100 years due to groundwater extraction. During the 2010s, rates surpassing 30 centimeters/year were observed by satellite geodetic measurements. Not only does this subsidence pose grave challenges for buildings, urban infrastructure, and water management, but it also changes the seismic response of the affected subsurface layers and thereby alters the seismic hazard in the metropolis that has seen devastating site effects both in the 1985 Michoacan and 2017 Puebla earthquake. We use data and numerical modeling of ambient noise auto-correlations to gain a better insight into the subsidence process through ambient noise techniques.</p><p>We establish a baseline for the long-term and seasonal variations of seismic velocity near the basin from long-term recordings of the Geoscope station UNM, located at the Universidad Nacional Autónoma de México in the geotechnical hill zone. We further study temporary recordings from the MASE array (MASE (2007): Meso America Subduction Experiment. Caltech. Dataset. doi:10.7909/C3RN35SP) to see how subsidence and other factors may influence seismic velocity in the geotechnical hill, transition, and lake zones.</p><p>We find that seasonal oscillations and a strong, rapid velocity drop coincident with the 2017 Puebla earthquake overlay a multi-year increasing trend in seismic velocity. We cautiously interpret the multi-year increase as a long-term effect of subsidence. We further study the temporal correlations of seismic velocity changes with other environmental time series like precipitation, and model auto-correlations in order to improve our understanding of their composition and sensitivity.</p>

Interannual and Intra-seasonal Oscillations in the Length of Day, Atmospheric Angular Momentum and Atmospheric Surface Pressure Time Series Observed at Chosen Meteorological Stations Near the Equator

The atmospheric surface pressure time series of Madras, Darwin, and Tahiti together with non-tidal length-of-day (LODR) variations and axial component of atmospheric angular momentum (AAM) were analyzed by wavelet transform as well as the combination of the Fourier transform band pass filter with the Hilbert transform (FTBPF + HT) to detect interannual and intra-seasonal oscillations in them. It was found that annual oscillations in the atmospheric surface pressure variations of Darwin and Tahiti stations are in phase and are about 180o out of phase in the atmospheric surface pressure variations of Madras station. The phase of the annual oscillation in atmospheric surface pressure variations of Madras station is slightly greater (~ 20o) than the phase of the annual oscillation in the LODR time series. The amplitude and phase variations of the annual and semi-annual oscillations computed by the FTBPF + HT combination in LODR and the axial component of AAM are very similar. The mean amplitudes of the semi-annual oscillation in the atmospheric surface pressure variations of Madras and Tahiti are of the order of 0.4 hPa, the phases of these oscillations are stable and the amplitude of the semi-annual oscillation in the atmospheric surface pressure variations of Darwin is negligible due to unstable phase of this oscillation. The atmospheric surface pressure variations of Madras, Darwin, and Tahiti stations show similar amplitude wideband signals with a central period of ~ 4 years (cutoff periods ranging from about 2.2 to 20 years) related to El Niño phenomenon. The amplitude maxima of this signal corresponding to the strongest El Niño events in 1982-83, 1997-98, and 2014-15 are also present in amplitude variations of this signal in the LODR and AAM χ3 time series.

Forcing Seasonality of influenza-like epidemics with daily Solar resonance

Seasonality of acute viral respiratory diseases is a well-known and yet not fully understood phenomenon. Here we show that such seasonality, as well as the distribution of viral disease’s epidemics with latitude on Earth, can be fully explained by the virucidal properties of UV-B and A Solar photons through a daily, minute-scale, resonant forcing mechanism. Such an induced periodicity can last, virtually unperturbed, from tens to hundreds of cycles, and even in presence of internal dynamics (host’s loss of immunity) much slower than seasonal will, on a long period, generate seasonal oscillations.