答案窝,daanwo.com

[共享题干题]【2013年真题】      （一） Forecasting Method       There are several different methods that can be used to create a forecast. The methodforecaster chooses depends upon the experience of the forecaster, the amount of informationavailable to the forecaster, the level of difficulty that the forecast situation presents, and thedegree of accuracy or confidence needed in the forecast.       The first of these methods is the persistence method; the simplest way of producing aforecast. The persistence method assumes that the conditions at the time of the forecast will notchange. For example, if it is sunny and 87 degree today, the persistence method predicts that itwill be sunny and 87 degree tomorrow. If two inches of rain fell today, the persistence methodwould predict two inches of rain for tomorrow. However, if weather conditions changesignificantly from day to day, the persistence method usually breaks down and is not the bestforecasting method to use.      The trends method involves determining the speed and direction of movement for fronts,high and low pressure centers, and areas of clouds and precipitation. Using this information, theforecaster can predict where he or she expects those features to be at some future time. Forexample, if a storm system is 1,000 miles west of your location and moving to the east at 250miles per day, suing the trends method you would predict it to arrive in your area in 4 days. Thetrends method works well when systems continue to move at the same speed in the samedirection for a long period of time. If they slow down, speed up, change intensity, or changedirection, the trends forecast will probably not work as well.     The climatology method is another simple way of producing a forecast. This methodinvolves averaging weather statistics accumulated over many years to make the forecast. Forexample, if you were using the climatology method to predict the weather for New York City onJuly 4th, you would go through all the weather data that has been recorded for every July 4thand take an average. The climatology method only works well when the weather pattern issimilar to that expected for the chosen time of year. if the pattern is quite unusual for the giventime of year, the climatology method will often fail.    The analog method is a slightly more complicated method of producing a forecast. Itinvolves examining today's forecast scenario and remembering a day in the past when theweather scenario looked very similar ( an analog). The forecaster would predict that the weatherin this forecast will behave the same as it did in the past. The analog method is difficult to usebecause it is virtually impossible to find a predict analog. Various weather features rarely align themselves in the same locations they were in the previous time. Even small differences betweenthe current time andre analog can lead to very different results.
单选题第1题Which of the following is NOT mentioned in choosing a forecasting method__________?
A.Necessary amount of informatio
B.Degree of difficulty involved in forecastin
C.Practical knowledge of the forecaste
D.Creativity of the forecaste

答案窝,daanwo.com