模式:

Times Series from the GFS Ensemble

更新:
2 times per day, from 10:00 and 23:00 UTC
格林尼治平时:
12:00 UTC = 20:00 北京时间
Resolution:
1.0° x 1.0°
参量:
Tmin 2m:
地面以上2米处的最低温度
描述:
这幅图显示由ANV-模式算出的6到12点和12到18点UTC的最低温度。 尽管模式算出的2米-温度同实测值常常不一致,但是只要满足下列条件:
1. 有850百帕温度资料;
2. 有天气报;
3. 有经验的预报员,
报好Tmin 2m 是完全可能的。

Cluster of Ensemble Members:
20 members of an ensemble run are divided into different clusters which means groups with similar members according to the hierarchical "Ward method" The average surface pressure of all members in each cluster are computed and shown as isobares. The number of members in each cluster determines the probability of the forecast (see percentage)
Dendrogram:
A dendrogram shows the multidimensional distances between objects in a tree-like structure. Objects that are closest in a multidimensional data space are connected by a horizontal line forming a cluster. The distance between a given pair of objects (or clusters) are indicated by the height of the horizontal line. [http://www.statistics4u.info/fundstat_germ/cc_dendrograms]. The greater the distance the bigger the differences.
NWP:
Numerical weather prediction uses current weather conditions as input into mathematical models of the atmosphere to predict the weather. Although the first efforts to accomplish this were done in the 1920s, it wasn't until the advent of the computer and computer simulation that it was feasible to do in real-time. Manipulating the huge datasets and performing the complex calculations necessary to do this on a resolution fine enough to make the results useful requires the use of some of the most powerful supercomputers in the world. A number of forecast models, both global and regional in scale, are run to help create forecasts for nations worldwide. Use of model ensemble forecasts helps to define the forecast uncertainty and extend weather forecasting farther into the future than would otherwise be possible.

Wikipedia, Numerical weather prediction, http://zh.wikipedia.org/wiki/數值天氣預報(as of Feb. 9, 2010, 20:50 UTC).