A weather map is an important tool for geographers. A succession of three or four maps presents a continuous picture of weather changes. Weather forecasters are able to determine the speed of air masses and fronts. They are also able to determine whether an air mass is retaining its original characteristics or taking on those of the surface over which it is moving. Thus, a most significant function of the map is to reveal an synoptic picture(气象图) of conditions in the atmosphere at a given time.
All students of geography should to interpret a weather map accurately. Weather maps contain an enormous amount of information about weather conditions existing at the time of observation over a large geographical area. They reveal in a few minutes what otherwise would take hours to describe. The United States Weather Bureau issues information about approaching storms, floods, frosts, droughts and all climate conditions in general. Twice a month it issues a 30-day “outlook” which is a rough guide to weather conditions likely to occur over broad areas of the United States. These outlooks are based on an analysis of the upper air levels.
With the use of electronic instruments and satellites, enormous gains have taken place recently in identifying and tracking storms over regions which have but few meteorological stations(气象站).Experiments are also in progress for weather modification studies, although few successful results such as artificial rainmaking have been achieved so far.
小题1: Which is not mentioned in this passage in the following about one characteristic of weather?
A．Fronts.
B．Temperature change.
C．Wind speed.
D．Frost.小题2:The observation of weather conditions by satellites is advantageous because
_______.
A．it is modern and sophisticated
B．it used electronic instruments
C．it enables man to alter the weather
D．it gives the scientists information not obtained readily otherwise小题3:The word “interpret” in Paragraph 2 most probably means _______
A．explain
B．present
C．modify
D．illustrate
