bluuebunny/crossref_metadata_2025_split huggingface dataset:
The dependence of gust factor probabilities on convective activity: Analysis conducted for Eurotunnel
Authors: Bradbury Wms , Deaves D M 
Published: June 2010

AbstractThe ratio of the maximum gust in an hour to the mean wind for the how is the ‘gust factor’. Extreme value analysis of gust factors was conducted as part of the design studies for Eurotunnel's Wind Alert System. This analysis indicated that the population of gust factors was mixed, suggesting that two different types of mechanism cause hourly gust maxima. Various investigations confirmed this indication and identified the two mechanisms. During the majority of hours the gust factor is a measure of the maximum gust due to the turbulent fluctuations of the atmospheric boundary layer. However, during a substantial minority of hours it is a measure of a gust caused by a ‘convective’ meteorological event such as a thunderstorm, squall line or heavy shower. The latter mechanism causes occasional exceptional gust factors, which can be of dominating importance for a transport system which must react when there is a risk of severe gusts.
Development of premium telephone weather services: A partnership between the public and the private sectors
Authors: Farrow R. 
Published: June 2010

AbstractThis paper outlines the background to the changes in the Met. Office telephone weather services and considers the effects chat this has had in the market place for readily available public information services. The launch of Weathercall and related services, the agreement between the Met. Office and Telephone Information Services plc ‐ which was one of the very first commercial agreements for o. form of joint venture between the public and private sectors ‐ has proved to be very successful. The partnership has exploited new market opportunities for premium, value‐added information services and greatly increased Met. Office revenues. The paper also considers ways in which telephone weather services can diversify into new ventures, directions and communications technologies in order to open up new revenue‐generating apportunties without creating demands for substantial additional resources within the Met. Office.
The separation of rain and hail using single polarisation radar echoes and IR cloud‐top temperatures
Authors: Hardaker P J , Auer A H 
Published: June 2010

AbstractA previous study has combined infrared cloud‐top temperature and single polarisation radar reflectivity to delineate between had and no‐hail situations and also to estimate had diameter assuming a mono‐disperse drop‐size distribution. The ‐work presented here builds on this previous study, to formalise the empirically derived results into an algorithm that is intended to be of benefit to an operational forecast system.
Gust factors within frontal depressions at Rio, Greece
Authors: Ahmed Sharif 
Published: June 2010

AbstractWind gust factors are determined from data obtained on the south shore of the Rio‐Antirio Strait, at the western entrance of the Gulf of Corinth, during the passage of frontal depressions. It was found that in this region the wind gusts decrease as the wind speed increases. The measured gust factors fall in‐between those used for structural design in the United Kingdom and those used in the United States.
A case study of a mesoscale trapped gravity wave accompanied by severe weather
Authors: Rasmussen Erik A 
Published: June 2010

AbstractThe unexpected development of a mesoscale disturbance accompanied by severe weather in the form of strong convection, dense snow and strong gusty winds at a synoptic situation where most of Denmark would normally he sheltered by the Norwegian mountains is discussed. Using all the meteorological data available, including a variety of non‐synoptic data, supported by a linear model, it is concluded that the phenomenon which caused the outbreak of severe weather was a low‐level ‘trapped’ or ‘ducted’ gravity wave.
The directional‐dependence of the enhancement of rainfall over complex orography
Authors: Weston Keith J , Roy Marjory G 
Published: June 2010

AbstractRainfall over Scotland is analysed to determine the distributions of rainfall amount associated with flow from different directions. The dominant effects of orography are dearly displayed, with large amounts of rainfall over the first area of high ground encountered and a rapid decline downwind; indeed, amounts are already declining before the highest ground is reached. This general behaviour applies to all flow directions, including those in which showery precipitation predominates. A simple model of mean orographic enhancement is developed which incorporates cloudwater generation by orographic and synoptic‐scale lifting, the conversion of cloud‐water to rainwater and wind‐drift of falling precipitation. This model allows spatially detailed patterns of rainfall to be inferred. The dependence of rainfall enhancement on wind speed is investigated with the model: over the first area of high ground there is an almost linear increase of rainfall with increasing wind speed, hut over subsequent high ground rainfall amounts decrease with increasing speed, in accord with observations.
The diagnosis and forecast of clear sky ultraviolet levels at the Earth's surface
Authors: Austin J , Barwell B R , Cox S J , Hughes P A , Knight J R , Ross G , Sinclair P , Webb A R 
Published: June 2010

AbstractA climatology of clear sky ultraviolet (UV) levels, weighted by the sensitivity of human skin, is presented. Away from the tropics the values are shown to be strongly dependent on the time of year, with peak values occurring in midsummer. Near the equator two annual maxima occur due to the twice‐yearly passage of the sun over the equator. The second factor influencing clear‐sky UV levels is the total ozone amount. In mid latitudes, because of lower ozone amounts, UV levels are generally higher around the autumn equinox than at the spring equinox. High UV levels also occur locally in spring due to the Antarctic ozone hole, although Arctic spring values have not yet been significantly affected. Next, total ozone amounts are shown to be related to meteorological parameters. Using a simple representation of the UV level in terms of the solar zenith angle and total ozone amount, an operational procedure for forecasting UV levels is outlined Finally, some comparisons with observed UV levels are presented and a sample UV forecast is shown.
Use of satellite imagery to diagnose events leading to frontal thunderstorms: Part II of a case study
Authors: Browning K A , Roberts N M 
Published: June 2010

AbstractConvective and mesoscale processes can be diagnosed in some detail by careful scrutiny of high‐resolution satellite imagery. An example is presented in which lines of convergence within warm, moist, low‐level air created a series of very straight rope‐like clouds whose smooth texture, as seen by polar orbiting satellite imagery, indicated that they were capped by a stable lid. The moist air deepened with time until the lid was penetrated and deep convection was observed to break out. The rope‐like clouds occurred near the leading edge of a so‐called dry intrusion and they are believed to have been associated with the kind of multiple cold frontal structure often encountered in such regions.
Methods for assessing the benefits of meteorological services in Australia
Authors: Anaman Kwabena A , Thampapillai Dodo J , Henderson‐Sellers A , Noar Peter F , Sullivan Patrick J 
Published: June 2010

AbstractA review of several methods for assessing the economic and social benefits of meteorological services provided in Australia is undertaken. Meteorological services discussed are the basic public weather service and several user‐pay specialised services produced by the Australian Bureau of Meteorology for firms in various sectors of the economy. The usefulness and limitations of the contingent valuation technique often used to estimate the economic value of public goods and services (such as the basic public weather service) are reviewed. Methods for valuing the economic benefits of user‐pay services discussed include the direct economic benefits derived from the use of meteorological services for producers and consumers based on the producer and consumer surplus concepts, simulation modelling incorporating economic optimisation based on the cost–loss ratio technique and cost function analysis to establish the effect of the quality of weather information on the operating costs of a business firm. The social or non‐economic benefits of meteorological services are also discussed, including the difficulty of placing monetary values on these benefits.
Fog forecasting in Cuba. Neural networks versus discriminant analysis
Authors: Naranjo‐Diaz Lino R , Alfonso Arnaldo P 
Published: June 2010

AbstractTwo methods for fog forecasting in Cuba are compared: use of the classical Fisher discriminant function, and the LVQ algorithm developed by the Laboratory of Computer and Information Sciences, Helsinki University of Technology. The relative number of correct forecasts is over 70% for both, which can be considered a good performance. When the learning sample is large enough and nearly equi‐probabalistic, the LVQ algorithm provides a greater number of correct forecasts than those obtained via the Fisher discriminant function. However, the results attained via the LVQ algorithm are not steady when the learning sample is far from being equi‐probabalistic, because the number of fog cases is much reduced. Until larger samples are available for some regions, it will be necessary to use both methods for fog forecasting in Cuba.
Variation in air and sea‐surface temperatures and their effect on anchovy fishing along the south‐eastern Black Sea coast
Authors: Durukanoǧlu H Fehmi 
Published: June 2010

AbstractThis paper deals with the influence of the annual temperature distribution on anchovy fishing in Trabzon and its surroundings (which have been taken to be representative of the coastal region of the south‐east Black Sea). Data used in this study come from two periods: 1960 to 1990 and 1987 to 1992. It is shown that the variation in temperature distribution has no effect on anchovy fishing. Also, it is demonstrated that commercial fishing takes place when the temperature is lower than the annual mean.
Excessive rainfall over the Belgian Ardennes in December 1993: Evaluation of model predictions
Authors: Van Meijgaard Erik 
Published: June 2010

AbstractDecember 1993 turned out to be very wet on the European continent. Around 20 December the Meuse basin in Belgium and France was hit by an unusual amount of precipitation, which gave rise to extensive flooding of the Meuse in the Dutch province of Limburg. For a 33‐day period starting on 6 December 1993 the precipitation forecasts for the Belgian Ardennes were evaluated using the observations of 20 Belgian climate stations. Besides short‐term forecasts made with regional models like the HIRLAM, level 2.0, the UKMO‐model and the RACMO/HIRHAM, precipitation prognoses extracted from ECWMF‐forecasts were examined. On average all model predictions were too low, varying from 10% for the 36‐ to 60‐hour (day‐2) ECMWF‐forecast to over 50% for the 6‐ to 30‐hour UKMO‐forecast. On the other hand, the UKMO‐forecast correlated best with the observations (0.85). The rainfall on 20 December, the wettest day, was underestimated by all model predictions, with the exception of the day‐2 ECMWF‐forecast. With the RACMO/HIRHAM a three‐day rerun was made starting from the 1200 UTC ECMWF‐analysis on 18 December 1993. The resulting precipitation on 20 December compared very well with the data. A similarly prepared HIRLAM‐run, however, performed worse compared with the operational run.
Practical subjective application of the omega equation and Sutcliffe development theory
Authors: Carroll Edward B 
Published: June 2010

AbstractSutcliffe development theory and the similar omega equation provide an objective framework for the understanding of synoptic‐scale development in the extra‐tropics. Both are widely applied by forecasters in the UK Met. Office, with the omega equation also being used by forecasters working in other meteorological services. Using results from experiments with a quasi‐geostrophic numerical model, this paper examines the pitfalls associated with each, and suggests ways in which these can be avoided. The partitioning between so‐called steering and development terms in the Sutcliffe equation is shown to be misleading, and an alternative form is suggested which is more accurate and circumvents significant cancellation problems associated with the existing form. It is shown that oversimplifiction of the omega equation can lead to it being applied in unsuitable ways. In particular, it is argued that the conversion from omega forcing to vertical velocity is best made at the mid‐tropospheric level, say at 500 hPa, and that therefore diagnostics such asQ‐vectors or their divergence are better applied at this level than, say, at 700 hPa. The so‐called Sutcliffe, or Trenberth, form of the omega equation is recommended as being suitable for subjective application.
Test results from a Mobile Profiler System
Authors: Cogan J 
Published: June 2010

AbstractA Mobile Profiler System is being developed to provide operational users with atmospheric soundings in near to real time. The reduction of refresh time from the 2 to 12 hours of traditional rawinsonde systems to as short as 3 to 5 minutes should considerably reduce errors caused by time staleness. The mobile profiler combines a small satellite receiver and processor with ground‐based remote‐sensing systems and a portable meteorological ground station. Ground‐based systems include a 924 MHz radar wind profiler, a radio acoustic sounding system for virtual temperature, and a multi‐channel microwave radiometer for virtual temperature and total water vapour and liquid water content. Satellite soundings contain temperature, dew point and the derived variables of wind speed and direction. This paper describes the mobile profiler, provides a very brief outline of the combined sounding technique and presents some results from field tests. Comparisons with rawinsonde soundings nearly coincident in space and time provide an indication of the accuracy of the system. For the merged soundings, average standard deviations and means for virtual temperature were about 1.5 to 2.0 K and ±0.5 K, respectively. Preliminary results for wind speed suggested values consistent with those reported in the literature, but were inconclusive for wind direction.
A comparative real‐time trial between the UK Met. Office and Oceanroutes to predict road surface temperatures
Authors: Thornes John E 
Published: June 2010

AbstractA comparative trial between the Met. Office and Oceanroutes to predict road surface temperatures for a motorway site in Cumbria was held in the spring of 1994. Hourly data for 26 nights when the minimum road surface temperature was equal to or less than 5 °C have been analysed and the results show no significant difference between the accuracy of the forecast for the two organisations. An end‐user specification for road weather forecast providers is also presented.
On estimating extreme wind speeds from short‐period data
Authors: Ahmed Sharif I. 
Published: June 2010

AbstractTwo methods based on the Weibull distribution were used to estimate the extreme wind speeds, with recurrent intervals of 50 and 100 years, from short‐period data. Three years of data were separated into periods of one, two and three years. For each period we applied the least‐squares fit method and the mean wind speed and the standard deviation method, and estimated the extreme wind speeds. Also, we used the classical method of moments to estimate the extreme speeds from the three years of data. The extreme wind speeds estimated by these two methods were found to be in agreement with those processed by the classical method of moments.
The Farnborough Storm—evidence of a microburst
Authors: Waters A J , Collier C G 
Published: June 2010

AbstractObservations from radar, satellite and conventional ground‐based sources are shown as evidence for the occurrence of a microburst during a severe thunderstorm at Farnborough, Hampshire, UK on 24 May 1989. The data are compared with published analyses of microbursts in the USA, and it is concluded that the microburst observed in the UK is comparable. A descriptive model of the evolution of the gust front and microburst is proposed.
Extreme warm frontal icing on 25 February 1994 causes an aircraft accident near Uttoxeter
Authors: Pike W S 
Published: June 2010

AbstractAn active, double warm‐frontal zone, aligned WNW‐ESE over the British Isles, produced copious precipitation over a wide area from southern Scotlant to the English Midlands during the evening of 25 February 1994. A turboprop cargo aircraft carrying Royal Mail parcels from Edinburgh to the intended destination of Coverntry suffered severe icing during its descent from 18000 ft over Manchester Airport, flying SSE wards in frontal nimbostratus. Then, some freezing rain was encountered below about 3000 ft over snow‐covered ground during the final stages of the flight. At one time, three of the four engines had ‘flamed‐out’, and subsequent attempts to re‐start both of the failed starboard (windward) side engines were unsuccessful. While the official report criticises the crew for following incorrect drills, and for not using their weather radar; eventually the asymmetric build‐up of ice on the windward‐side airframe and dead engines made the aircraft uncontrollable.
New estimates of probable maximum precipitation in South West England
Authors: Clark C 
Published: June 2010

AbstractTwo methods have been used to estimate the probable maximum precipitation (PMP) over South West England. The first is based on an analysis of rainfall frequency data; the second uses depth duration data from rare storms. Both methods give results of around 500 mm for the 24‐hour PMP, which for many parts of the region is considerably higher than that given by the Flood Studies Report. By relating PMP to average annual rainfall, new maps of the distribution of PMP over South West England were produced. Values of PMP are highest on low ground, reflecting the effect of convectional processes in these areas.
Weather forecasting for aviation and marine operations in the Antarctic Peninsula region
Authors: Wattam S , Turner J 
Published: June 2010

AbstractAn account is given of one Austral summer's experience of forecasting for flying activities and marine operations around the Antarctic Peninsula. Data available included surface and upper‐air observations, analyses and forecasts from the UK Meteorological Office global, 19‐level model and AVHRR satellite imagery. The numerical analyses and forecasts provided good guidance and correctly represented most of the synoptic‐scale features. A number of mesoscale disturbances affected the central Peninsula area and the AVHRR imagery was very valuable in allowing the development and track of these systems to be followed. The major problems were the absence of observations to the west of the Peninsula, the lack of radiosonde ascents from the Peninsula itself and the complexity of local wind systems as a result of the topography. Forecasting frontal activity over the ocean areas was also very difficult because of the unavailability of precipitation forecasts in the GRIB data.
Use of INSAT winds for better depiction of monsoon depressions over the Indian region
Authors: Mahajan P N , Talwalkar D R , Chinthalu G R , Rajamani S 
Published: June 2010

AbstractThis study is aimed at evaluating the impact of non‐conventional winds using data obtained by INSAT satellites over the Indian region. The emphasis is on whether the satellite‐derived wind data improve the depiction of monsoon system, flow patterns, the centre of the system, etc. in the objective analysis of the wind field. For this purpose, monthly climatological normals of the wind field are considered as the initial guess field and then objective analyses of the wind field are performed, first using only conventional winds over the land areas and subsequently including winds constructed from cloud‐motion vectors at 850 and 700 hPa. This experiment was performed for the period of 19–21 September, 1991, when a monsoon depression formed over the Bay of Bengal. Verification of these analyses were made by comparing them with carefully drawn subjective analyses. It is inferred that INSAT winds have a positive impact on the objective analysis, and improvement in the analysis is more marked over the data‐void regions of the Arabian sea and the Bay of Bengal. The results presented in the study reveal that INSAT winds are of potential use in the objective analysis of the wind field, thus giving a better depiction of monsoon depression over the Indian region.
The impact of radar and raingauge sampling errors when calibrating a weather radar
Authors: Seed A W , Nicol J , Austin G L , Stow C D , Bradley S G 
Published: June 2010

AbstractThis paper investigates the impact of sampling errors on the estimation of the parameters of the relation Z = aRb used in the measurement of rainfall (R) from radar reflectivity (Z). Simulation results show that, at levels of sampling errors likely to be observed in real data sets, of the order 100 gauge and radar observation pairs are required to estimate a with an accuracy better than 15% and b better than 10%. Errors in radar rainfall estimates for rain rates less than 15 mm h−1 are insensitive to the Z‐R parameters. High‐resolution measurements from a vertically pointing radar (300 to 400 m above ground level, 1‐minute averages) are compared with raingauge measurements taken at the radar site during a period of widespread rainfall. The radar provided surprisingly poor estimates of rain rates, with mean standard errors of 80% for rain rates less than 2 mm h−1. The auto‐correlations of the residuals in the radar estimates were found to be very low after only 2 minutes, leading to the conclusion that radar estimates of rainfall intensities should be made at a high space/time resolution and then averaged so as to reduce measurement errors arising from sampling problems.
Producers' evaluation of an enhanced weather information service for the cotton industry in Australia
Authors: Anaman Kwabena A , Lellyett Stephen C 
Published: June 2010

AbstractThe study is concerned with producers' evaluation of an enhanced weather information service called the Cottonfields Weather Service produced by the Australian Bureau of Meteorology. The service has been in existence since the 1992/93 production year. It provides, at some cost to producers, the latest weather information for their locality, which is more detailed than the information obtained from the basic public weather service provided free of charge through the mass media. Access to the service is through a phone facsimile machine. The study involved a sample survey of 108 members of the Namoi Cotton Co‐operative, one of the largest cotton producing groups in Australia. Producers' assessment of the service was based on numerical scoring of key quality attributes of information for managerial decision making such as timeliness, ease of understanding, accuracy and overall usefulness. Results of the analysis indicated that about 51% of the members of the Co‐operative have adopted the service. Users generally considered the service to be of high quality, useful and effective. There was little variation in producers' assessment of various information quality attributes of the service. The level of formal education appeared to be the significant socio‐economic variable influencing the adoption of the service.