Forecasting Methods

There are several different methods that can be used to create a forecast. The method a forecaster chooses depends upon the experience of the forecaster, the amount of information available to the forecaster, the level of difficulty that the forecast situation presents, and the degree of accuracy or confidence¹ needed in the forecast.

The first of these methods is the persistence method; the simplest way of producing a forecast. The persistence method assumes that the conditions at the time of the forecast will not change. For example, if it is sunny and 87 degrees today, the persistence method predicts that it will be sunny and 87 degrees tomorrow. If two inches of rain fell today, the persistence method would predict two inches of rain for tomorrow. However, if weather conditions change significantly² from day to day, the persistence method usually breaks down³ and is not the best forecasting method to use.

The trends method involves determining⁴ the speed and direction of movement for fronts⁵, high and low pressure centers, and areas of clouds and precipitation. Using this information, the forecaster can predict where he or she expects those features⁶ to be at some future time. For example, if a storm system is 1,000 miles west of your location and moving to the east at 250 miles per day, using the trends method you would predict it to arrive in your area in 4 days. The trends method works well when systems⁷ continue to move at the same speed in the same direction for a long period of time. If they slow down, speed up, change intensity, or change direction⁸, the trends forecast will probably not work as well.

The climatology method is another simple way of producing a forecast. This method involves averaging weather statistics accumulated over many years to make the forecast. For example, if you were using the climatology method to predict the weather for New York City on July 4th, you would go through all the weather data that has been recorded for every July 4th and take an average. The climatology method only works well when the weather pattern is similar to that expected for the chosen time of year. If the pattern is quite unusual for the given time of year, the climatology method will often fail.

The analog method is a slightly more complicated method of producing a forecast. It involves examining today’s forecast scenario and remembering a day in the past when the weather scenario looked very similar (an analog⁹). The forecaster would predict that the weather in this forecast will behave the same as it did in the past. The analog method is difficult to use because it is virtually¹⁰ impossible to find a predict analog. Various weather features rarely align themselves in the same locations as they were in the previous time¹¹. Even small differences between the current time and the analog can lead to very different results.

 

词汇:

forecaster /5fC:kB:stE/n.(天气)预报员    下:降水量 ;降雨量

climatology /klaimE5tClEdVi/n.气候学    

scenario /si5nB:riEu/n.某事物（件）的模式，状况

precipitation /pri7sipi5teiFEn/n.(雨、雪、冰雹等的 )降      

 

注释：  

1. the degree of accuracy or confidence: cnedifnoc指的是“置信度”，所以该词之前用 or说明与 the degree of accuracy有意义上的联系，不能解释为“信心”。

2. significantly:意为“ greatly, considerably”(显著地 )。

3. break down:意为“ fail”(出问题，出故障 )。

4. determining: determine (确定)的动名词形式，其后跟三个宾语 : the speed and direction of movement for front high and low pressure centers, and areas of clouds and precipitation.

5. front:铮(锋面:不同温度和密度的两大气团交界处 )，如: cold front冷锋 warm front热锋

6. features:指上句中 determining的三个宾语所涉及的内容。见注释 4。

7. system:意为“a group of naturally occurring phenomena”(一组自然现象 )。这里指风暴等自然现象。见前句 : … if a storm system is 1,000 miles west of …

8. If they slow down, speed up, change intensity, or change direction,…：如果他们减速，或加速，或强度发生变化，或方向改变……

9. analog:相似物

10. virtually:事实上

11. various weather features rarely align themselves in the same locations as they were in the previous time:不同的天气特征很少同时出现在与前次出现时一样的地点。

Which method may involve historical weather data?

A:The trends method. B:The analog method. C:Both climatology method and analog method. D:The trends method and the persistence method.

{{B}}第三篇{{/B}}

Which method may involve historical weather data?

A:The trends method. B:The analog method. C:Both climatology method and analog method. D:The trends method and the persistence method.

? ?There are several different methods that can be used to create a forecast. The method a forecaster chooses depends Upon the experience of the forecaster, the amount of information available to the forecaster, the level of difficulty that the forecast situation presents, and the degree of accuracy or confidence needed in the forecast.
? ?The first of these methods is the persistence method; the simplest way of producing a forecast. The persistence method assumes that the conditions at the time of the forecast will not change. For example, if it is sunny and 87 degree today, the persistence method predicts that it will be sunny and 87 degree tomorrow. If two inches of rain fell today, the persistence method would predict two inches of rain for tomorrow. ?However, if weather conditions change significantly from day to day, the persistence method usually breaks down and is not the best forecasting 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, the forecaster can predict where he or she expects those features to be at some future time. For example, if a storm system is 1,000 miles west of your location and moving to the east at 250 miles per day, suing the trends method you would predict it to arrive in your area in 4 days. The trends method works well when systems continue to move at the same speed in the same direction for a long period of time. if they slow down, speed up, change intensity, or change direction, the trends forecast will probably not work as well.
? ?The climatology method is another simple way of producing a forecast. This method involves averaging weather statistics accumulated over man years to make the forecast. For ex- ample, if you were using the climatology method to predict the weather for new York City on July 4th, you would go through all the weather data that has been recorded for every July 4th and take an average. The climatology method only works well when the weather pattern is similar to that expected for the chosen time of year. if the pattern is quite unusual for the given time of year, the climatology method will often fail.
? ?The analog method is a slightly more complicated method of producing a forecast. It involves examining today’s forecast scenario and remembering a day in the past when the weather scenario looked very similar (an analog). The forecaster would predict that the weather in this forecast will behave the same as it did in the past. The analog method is difficult to use because 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 between the current time and the analog can lead to very different results.

Which method may involve historical weather data?______

A:The trends method. B:The analog method. C:Both climatology method and analog method. D:The trends method and the persistence method.

{{B}}第二篇{{/B}}

Which method may involve historical weather data?

A:The trends method. B:The analog method. C:Both climatology method and analog method. D:The trends method and the persistence method.

有一个接口定义如下，下列选项中实现了该接口并且不是抽象的是 interface A { int method1(int i); int method2(int j)； }

A:class Ｂ implements Ａ　　　　{　　　　　int method 1(){}　　　　　int method 2(){}　　　　} B:class Ｂ　　　　{　　　　　int method 1(int {}　　　　　int method 2(int {}　　　　} C:class Ｂ implements Ａ　　　　{　　　　　int method 1(int {}　　　　　int method 2(int {}　　　　} D:class Ｂ extends Ａ　　　　{　　　　　int method 2(int {}　　　　　int method 1(int {}　　　　}

有一个接口定义如下： interface A { int method1(int i); int method2(int j); } 那么下面各项中实现了该接口并且不是抽象类的是( )。

A:class B implements A { int method1(){} int method2(){} } B:class B { int method1(int {} int method2(int {} } C:class B implements A { int method1(int {} int method2(int {} } D:class B extends A { int method1(int {} int method2(int {} }

There are many methods in the CPETT .One of them is the method that runs a Kernel as the load of a computer. So we call it

A:Monitor method B:Model method C:Benchmark method D:Physical method

接口A的定义如下，指出下列哪些类实现了该接口______。 Interface A { Int method1 (int i); Int method2 (int j); }

A:class B implements A { Int method1(){} Int method2(){} } B:class B extends A { Int method1(int {} Int method2(int {} } C:class B { Int method1(int {} Int method2(int {} } D:class B implements A { Int method1(int {} Int method2(int {} }