Since most of the inhabitants in West Africa is working with, or are dependent on agricultural work, accurate weather forecasts are important in their daily work. Knowledge of when to start to sow is one of the most important features from a farmer’s point of view. It can be devastating for the farmers if the soil is not moist enough when planting since the crops risks to dry out, but also planting too late needs to be avoided since it will affect the growing time and therefore might reduce the production. In this thesis, investigations whether the start of the rainy season in Ghana and parts of Burkina Faso is predictable, only with the use of patterns in rainfall and changes in sea surface temperature in the Gulf of Guinea. The region of interest has been divided into four equally sized areas with a latitudinal width of 2  from south to north. The models are first of all predicting the start of the rainy season in the southernmost area by use of four different methods, three that are based on precipitation patterns and one based on changes in sea surface temperature. Thereafter, the three northerly areas are predicted with a linear function based on when the rainy season started in the southernmost area. The results shows that the model is acceptable in its predictability but is very good in indicating if the rainy season will start earlier or later than the year before. This is of major benefits for the farmers in the region. On a long‐range average, the rainy season starts in the southernmost area first and then it starts further north, but this is not always the case in individual years, which makes the models complicated to use in some years. In order to give reliable forecasts to the farmers, the rainy season needs to be defined so it fulfils the conditions that are needed for plants to grow. Therefore, the start of the rainy season is defined as when 40 mm of precipitation is received during a five‐day period with at least 16 mm in one of these five days. Thereafter, the next 30 days cannot contain more than 18 days without precipitation. / Eftersom de flesta invånarna i Västafrika arbetar med, eller är beroende av jordbruksarbete så är väderprognoser till stor hjälp i det dagliga arbetet. Att ha kännedom om när det är lämpligt att börja så är en av de viktigaste aspekterna ur böndernas perspektiv. Att börja så innan marken är tillräckligt fuktig kan leda till förödande konsekvenser för bönderna då grödorna riskerar att torka ut och dö, men även att vänta för länge med att så bör undvikas eftersom det påverkar längden på skördesäsongen och därmed också produktionen. I den här studien har det gjorts undersökningar om det är möjligt att göra prognoser för när regnperioden börjar i Ghana och delar av Burkina Faso med hjälp av nederbördsfördelningen och förändringar i ytvattentemperaturen i Guineabukten. Regionen har delats in i fyra lika stora områden med latitudinell bredd på 2 ° från söder till norr. Modellerna börjar med att göra en prognos för regnperiodens början i det sydligaste området med hjälp av fyra olika metoder, tre som är baserade på nederbördsfördelningen och en som är baserad på ändringar i ytvattentemperaturen. Därefter görs prognoser för de tre nordligare områdena med hjälp av en linjär funktion baserad på när regnperioden började i det sydligaste området. Resultaten visar att modellen är acceptabel när det gäller att komma så nära den verkliga starten som möjligt, men är väldigt bra på att indikera om regnperioden kommer att börja tidigare eller senare än året innan. Detta är till stor nytta för bönderna i området. Över ett längre perspektiv så börjar regnperioden först i det sydligaste området för att sedan börjar längre norrut, men så ser det inte ut i varje enskilt år, vilket gör att modellerna inte är användbara alla år. För att kunna ge bönderna så bra prognoser som möjligt så behöver regnperioden definieras så att den uppfyller de villkor som krävs för att de ska kunna börja så. Därför har regnperiodens början definierats som när 40 mm nederbörd mottagits under en femdagarsperiod med minst 16 mm under en av dessa fem dagar. Därefter får de närmaste 30 dagarna inte innehålla mer än 18 dagar utan nederbörd.

This paper examines the effects of disclosures on information asymmetry by studying bid-ask spreads around independent management forecasts and earnings announcements released with forecasts. The findings suggest the disclosure of independent management forecasts increase information asymmetry in the market rather than resolving it. Regulation FD has reduced the overall level of information asymmetry in the market with respect to both earnings announcements and management forecasts although it has a greater effect on management forecasts, post-forecast spreads. Closer analysis reveals that when “good news” forecasts and separated from “bad news” independent management forecasts, good news management forecasts decrease information asymmetry. Since initial tests demonstrated that management forecasts increase information asymmetry, these findings suggests that the magnitude of the effect of bad news management forecasts is greater than that of good news forecasts.

This dissertation focuses on (river) forecasting, but also includes a study on stormwater treatment. Using forecasts for decision-making is complicated by their inherent uncertainty. An interview-based study qualitatively and a survey empirically investigate forecast use in emergency management. Emergency managers perceive uncertainty as a given rather than as a problem. To cope with the uncertainty, decision-makers gather as much information as possible; forecasts are only one piece of information among many. For decision-making, emergency managers say that they rely more on radar than on river forecasting. However, forecasts play an important role in communication with the public, because they are the official interpretation of the situation. Emergency managers can add a lot of value to those forecasts by combining them with local knowledge, but might not do so because of accountability concerns. Forecasts must have value to emergency managers, because those with more work experience rely more on them than those without. Another study further develops the application of quantile regression to generate probabilistic river forecasts. Compared to existing research, this study includes a larger number of river gages; includes more independent variables; and studies longer lead times. Additionally, it is the first to apply this method to the U.S. American context. It was found that the model has to be customized for each river gage for extremely high event thresholds. For other thresholds and across lead times, a one-size-fits-all model suffices. The model performance is robust to the size of the training dataset, but depends on the year, the river gage, lead time and event threshold that are being forecast. An additional study considers the robustness of stormwater management to the amount of runoff. Impervious surfaces, such as roads and parking lots, can increase the amount of runoff and lead to more pollution reaching streams, rivers, and lakes. Best Management Practices (BMPs) reduce the peak discharge into the storm sewer system and remove pollutants such as sediments, phosphorus and nitrogen from the stormwater runoff. Empirically, it is found that BMP effectiveness decreases sooner, steeper and deeper with increasing sizes of storm events than assumed in current computer models.

There has been an increasing interest in the finance literature regarding the impact of transactions costs on US equity markets. The US empirical evidence indicates that transactions costs influence both trading volume (Atkins and Dyl (1997)) and asset returns (Amihud and Mendelson (1986)). Additionally, the theoretical finance literature also indicates that transactions costs affect equilibrium asset returns (Fisher (1994)). In this thesis we assess the impact of transactions costs on the UK equity markets, from four aspects. Firstly, we provide empirical support to the hypothesis that transactions costs affect the "holding period" of an asset in the portfolio of an investor. Secondly, we provide robust results showing that transactions costs affect equilibrium asset returns. Thirdly, we explain the variability of transactions costs with the use of information asymmetry, proxied by the variance of analysts' forecasts, in the spirit of Kim and Verrecchia (1994, 2001). Finally, we find that stock price and trading volume reaction to changes in the FTSE 100 list can be explained by liquidity effects, as proxied by the bid-ask spread. We provide overwhelming evidence, suggesting that transactions costs are important in UK equity markets.

The present study aims to develop an analysis package for combining forecasts that are obtained from different forecast methods. The package is composed of three modules, namely, the data input module, the data analysis module and the combination module. In data input module, the data is entered and saved as an Excel file with the given name. In data analysis module, the program computes the forecasts of the selected methods and displays the forecast results, the mean absolute errors, the mean square errors and the mean absolute percentage errors of these methods. In combination module, the forecast results, computed in the data analysis module, are combined according to the selected combination methods. All the detailed calculations of the forecasts and the values assigned by the program to minimize the mean absolute deviations, the mean square errors and the mean absolute percentage errors are displayed under the columns of the related method on the Excel spreadsheet of the file.

This study examines the making of the European identity concept under the impact of the European Union (EU) project. In order to define the structure of the European identity, theoretical and historical aspects have been scrutinised. Besides, the Eurobarometers (EBs) have been used to analyse the condition of European identity perception among the people of the member countries. The results of the EBs data show that the popularisation of the European identity is limited and the elite character of this identity seems dominant. The EU still lacks its common political identity, which forms a political agenda, and a supranational political identity. This thesis has concluded that the popularisation of the European identity can ensure more political unity for the EU, and this unity can be realised only with a multiple identity perception including current strong identities of the Europe.

This dissertation investigates the information considerations of volatility, pricediscovery and the relationship change in volume and volatility resulting from index derivatives transactions on financial markets in Australia. The impact of information on volatility was investigated in the essay one, as volatility is a key factor for accurately pricing derivative securities. I assessed the forecast accuracy, unbiasedness and information content of volatility forecasts, based on implied volatility and conditional volatility models for the S&P/ASX 200 Index Options market in Australia. The conditional volatility models produce the most accurate forecasts and are robust when forecasting into short time horizons. Essay two, investigates the information content of the index and option markets in the price-discovery process. Based on the above volatility results, the long-run equilibrium relationship between the share price index and the implied price of the share-price-index option was investigated. Causality was determined to show which market leads the other. Information share measures were used to gauge the contribution of the share price index and index option markets to the price-discovery process. Unambiguous evidence shows the index market leads the options market and the former contributes more to price-discovery than the latter. In essay three, I investigate the dynamic relationship between the future price volatility of the S&P/ASX 200 Index and the trading volume of the S&P/ASX 200 Index Options to explore the informational role of option volume in predicting price volatility. I found the contemporaneous call options volume have a significant strong positive feedback effect on the implied volatility, but the contemporaneous feedback effect of volume on the TARCH volatility is insignificant. The contemporaneous feedback effects from the implied volatility and the TARCH volatility to the call options volume are positive, significant and strong.

Thesis (Ph. D.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on March 11, 2008) Includes bibliographical references.

Thesis (M.Sc.(Meteorology))--University of Pretoria, 2008. / Summary in English. Includes bibliographical references.

Τα υποδείγματα δεικτών διάχυσης χρησιμοποιούνται για την πρόβλεψη χρονοσειρών όπως το ΑΕΠ ή ο πληθωρισμός.Η μέθοδος αυτή στηρίζεται στην εκτίμηση παραγόντων με την μέθοδο των κύριων συνιστωσών. / Diffusion Index Models are used in forecasts of time series such as GNP or inflation.This method is based on estimation of factors with the method of principal components.