scholarly journals Latent Heat Nudging in the Canadian Regional Deterministic Prediction System

2018 ◽  
Vol 146 (12) ◽  
pp. 3995-4014 ◽  
Author(s):  
Dominik Jacques ◽  
Daniel Michelson ◽  
Jean-François Caron ◽  
Luc Fillion

Abstract This study reports on the progress toward operational weather radar data assimilation in Canada. As a first step, the latent heat nudging (LHN) technique has been tested for a period of 1 month. It is the first time that LHN is used across the North American continent, a domain significantly larger than that of other LHN studies. Other novel aspects of this study include the use of a quality index associated with individual reflectivity measurements and a discussion on matching the effective resolution of the modeled precipitation for a reduction of the representation errors. Various verification scores indicate that LHN has a positive influence on instantaneous precipitation rates for lead times up to 3 h. In comparison, the nowcasting of precipitation rates by a simple Lagrangian extrapolation method yields improvements that last up to approximately 4 h. Verifications against aircraft measurements indicate small but statistically significant improvements throughout the troposphere for lead times up to 24 h.

2005 ◽  
Vol 119 (1) ◽  
pp. 82 ◽  
Author(s):  
Kathleen L. Londry ◽  
Pascal H. Badiou ◽  
Stephen E. Grasby

The chlorophycean alga Percursaria percursa (Ulvaceae, Ulvales, Chlorophyceae), typical of marine inter-tidal zones, is reported for the first time from hypersaline springs located along the north-western shore of Lake Winnipegosis in Manitoba. Although not usually found inland, P. percursa is the dominant member of microbial mat communities that thrive in shallow pools at the outlets of hypersaline springs.


Author(s):  
Melanya Stan

The sap beetle, Stelidota geminata (Say, 1825) originates from the North American continent and was introduced in Europe, Oriental Region and in the Near East. It is recorded from Romania for the first time.


1962 ◽  
Vol 60 (1) ◽  
pp. 1-20 ◽  
Author(s):  
Margaret D. Beech ◽  
A. E. Duxbury ◽  
Peter Warner

This paper consists of an epidemiological study of 52 cases of Q fever occurring in metropolitan Adelaide in 1957 and also a description of the results of a survey of 516 sera obtained from abattoir workers.The only case occurring outside the abattoirs was a dairy farmer who probably became infected while visiting the abattoirs. If this were so the incubation period (35 days) of his disease would have been exceptionally long.The general features of the outbreak, which lasted several months, differed from those on the North American continent in that the latter occurred explosively within a few days with very high attack rates. The situation in the Adelaide abattoirs is similar to that in Brisbane, where the disease appears to be endemic. However, unlike in Adelaide, cases are commonly recognized outside the abattoirs in Brisbane.In the abattoirs the disease affected mainly inspectors, those working on killing beef, and those working on offal. Mutton workers were not so severely affected. However, all these groups had similar incidences of low titre antibodies suggesting that in the past Q fever spread equally in all killing departments. In departments not directly associated with slaughtering the incidence both of cases in 1957 and low titre antibodies was relatively small.It was suggested that the epidemiological features of Q fever in Adelaide could be explained by the irregular appearance of animals from infected herds situated perhaps in Queensland—a known endemic area. Perhaps the appearance of such animals in the Adelaide abattoirs might be governed by meteorological conditions such that they were prevented from going to the ordinarily most convenient slaughterhouse.


2012 ◽  
Vol 27 (3) ◽  
pp. 757-769 ◽  
Author(s):  
James I. Belanger ◽  
Peter J. Webster ◽  
Judith A. Curry ◽  
Mark T. Jelinek

Abstract This analysis examines the predictability of several key forecasting parameters using the ECMWF Variable Ensemble Prediction System (VarEPS) for tropical cyclones (TCs) in the North Indian Ocean (NIO) including tropical cyclone genesis, pregenesis and postgenesis track and intensity projections, and regional outlooks of tropical cyclone activity for the Arabian Sea and the Bay of Bengal. Based on the evaluation period from 2007 to 2010, the VarEPS TC genesis forecasts demonstrate low false-alarm rates and moderate to high probabilities of detection for lead times of 1–7 days. In addition, VarEPS pregenesis track forecasts on average perform better than VarEPS postgenesis forecasts through 120 h and feature a total track error growth of 41 n mi day−1. VarEPS provides superior postgenesis track forecasts for lead times greater than 12 h compared to other models, including the Met Office global model (UKMET), the Navy Operational Global Atmospheric Prediction System (NOGAPS), and the Global Forecasting System (GFS), and slightly lower track errors than the Joint Typhoon Warning Center. This paper concludes with a discussion of how VarEPS can provide much of this extended predictability within a probabilistic framework for the region.


1950 ◽  
Vol 6 (04) ◽  
pp. 431-449 ◽  
Author(s):  
Joseph O. Baylen ◽  
Dorothy Woodward

On September 26, 1786, Don Francisco de Miranda, adventurer and patriot, secured a passport from the Austrian Minister in Constantinople which enabled him to continue his “grand tour” to Russia. The nature of Miranda’s subsequent visit, and the extent to which his reception at the court of Catherine II influenced Spanish and Russian policy, assumes significance in the light of events on the North American continent immediately preceding and during his stay in Russia.


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