Simulation of Hydrophysical Processes in Coastal Regions of the Sea

In the present work, we generalize the results of our investigations in the field of simulation of hydrophysical and ecological processes in coastal regions of various seas and some closed basins. The developed and applied mathematical models and the results of numerical experiments are briefly analyzed.     

Spectroscopic observations of parsamian 21

This work presents spectroscopic observations of Parsamian 21, which has been shown recently by Staude and Neckel to be a fuor-type star. A list of identified absorption lines is given. The results are compared with previous spectroscopic observations over the period 1966–1990. It is shown that the H line profile changed during this period; according to the observations of 1986, the center of the H absorption line was shifted by –140 km/sec from ₀ and reached –600 km/sec at the line edge. It follows from the presented lightcurve that the star has undergone brightness variations of nearly three magnitudes and most likely became a fuor before 1902.Translated fromAstrofizika, Vol. 39, No. 2, pp. 227–235, April–June, 1996.     

Trends in Canadian Short‐Duration Extreme Rainfall: Including an Intensity–Duration–Frequency Perspective

Short-duration (5 minutes to 24 hours) rainfall extremes are important for a number of purposes, including engineering infrastructure design, because they represent the different meteorological scales of extreme rainfall events. Both single location and regional analyses of the changes in short-duration extreme rainfall amounts across Canada, as observed by tipping bucket rain gauges from 1965 to 2005, are presented. The single station analysis shows a general lack of a detectable trend signal, at the 5% significance level, because of the large variability and the relatively short period of record of the extreme short-duration rainfall amounts. The single station 30-minute to 24-hour durations show that, on average, 4% of the total number of stations have statistically significant increasing amounts of rainfall, whereas 1.6% of the cases have significantly decreasing amounts. However, regional spatial patterns are apparent in the single station trend results. Thus, for the same durations regional trends are presented by grouping the single station trend statistics across Canada. This regional trend analysis shows that at least two-thirds of the regions across Canada have increasing trends in extreme rainfall amounts, with up to 33% being significant (depending on location and duration). Both the southwest and the east (Newfoundland) coastal regions generally show significant increasing regional trends for 1- and 2-hour extreme rainfall durations. For the shortest durations of 5–15 minutes, the general overall regional trends in the extreme amounts are more variable, with increasing and decreasing trends occurring with similar frequency; however, there is no evidence of statistically significant decreasing regional trends in extreme rainfall amounts. The decreasing regional trends for the 5- to 15-minute duration amounts tend to be located in the St. Lawrence region of southern Quebec and in the Atlantic provinces. Additional analysis using criteria specified for traditional water management practice (e.g., Intensity-Duration-Frequency (IDF)) shows that fewer than 5.6% and 3.4% of the stations have significant increasing and decreasing trends, respectively, in extreme annual maximum single location observation amounts. This indicates that at most locations across Canada the traditional single station IDF assumption that historical extreme rainfall observations are stationary (in terms of the mean) over the period of record for an individual station is not violated. However, the trend information is still useful complementary information that can be considered for water management purposes, especially in terms of regional analysis.