نتایج جستجو برای: forecasts

تعداد نتایج: 16075  

Journal: :فیزیک زمین و فضا 0
مجید آزادی استادیار، پژوهشگاه هواشناسی و علوم جو، تهران، ایران سعید واشانی استادیار، دانشگاه آزاد اسلامی واحد علوم و تحقیقات تهران، ایران سهراب حجام دانشیار، دانشگاه آزاد اسلامی واحد علوم و تحقیقات تهران، ایران

accurate quantitative precipitation forecasts (qpfs) have been always a demanding and challenging job in numerical weather prediction (nwp). the outputs of ensemble prediction systems (epss) in the form of probability forecasts provide a valuable tool for probabilistic quantitative precipitation forecasts (pqpfs). in this research, different configurations of wrf and mm5 meso-scale models form ...

Background and aims: Since accurate forecasts help inform decisions for preventive health-careintervention and epidemic control, this goal can only be achieved by making use of appropriatetechniques and methodologies. As much as forecast precision is important, methods and modelselection procedures are critical to forecast precision. This study aimed at providing an overview o...

2013
HUI WANG A. SANKARASUBRAMANIAN RANJI S. RANJITHAN

Skillful medium-range weather forecasts are critical for water resources planning and management. This study aims to improve 15-day-ahead accumulated precipitation forecasts by combining biweekly weather and disaggregated climate forecasts. A combination scheme is developed to combine reforecasts from a numerical weather model and disaggregated climate forecasts from ECHAM4.5 for developing 15-...

2003
Shripad Tuljapurkar Ronald D. Lee Qi Li Ronald D Lee

Probabilistic population forecasts are useful because they describe uncertainty in a quantitatively useful way. One approach (that we call LT) uses historical data to estimate stochastic models (e.g., a time series model) of vital rates, and then makes forecasts. Another (we call it RS) began as a kind of randomized scenario: we consider its simplest variant, in which expert opinion is used to ...

In this study, an investigation of long-term forecasts relating to the development of the transport sector in Poland is performed, including the ones by 2030 and 2050. Selected transport development forecasts from the perspective of the membership of Poland in the European Union are presented and most of all, from the perspective of national studies. The basement for the review was the prognosi...

Journal: :International Statistical Review 2007

2013
Rick Johnston Tong Kang Michael Wolfe

Recent research has begun to question the importance of forecasts to sell-side analysts. Prior research established the co-existence of longer horizon optimism and short-term pessimism in sell-side forecasts. These factors motivate us to explore a new phenomenon – crowdsourcing, as an alternative source of forecasts. We obtain revenue and earnings forecasts from estimize, an entity which crowds...

Journal: :فیزیک زمین و فضا 0
فرحناز تقوی استادیار، گروه فیزیک فضا، موسسه ژئوفیزیک دانشگاه تهران، ایران ابوالفضل نیستانی دانش آموخته کارشناسی ارشد هواشناسی، مؤسسه ژئوفیزیک دانشگاه تهران، ایران سرمد قادر دانشیار، گروه فیزیک فضا، موسسه ژئوفیزیک دانشگاه تهران، ایران

iran has a complex topography and it consists of rugged, mountainous rims surrounding high interior basins. because of this condition, in some cases the nwp output has a significant error from mesoscale variations induced by the diverse topography.  iran, covering an area of about 1,648,000 km2, is located in the southwest of asia approximately between 25° and 40° n and 44° and 64° e. this is p...

2006
MASAHIRO ASHIYA

We evaluate the relative accuracy of real GDP forecasts made by 25 Japanese economists over the past 15 years. The encompassing test reveals the following results. (a) All of these forecasts outperform naïve forecasts. (b) Their current-year forecasts are inferior to the corresponding forecasts of VAR, VECM, or the Japanese government. (c) Their year-ahead forecasts are inferior to the correspo...

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