A weather map is an important tool for geographers. A succession of three of four maps presents a continuous picture of weather changes. Weather forecasts are able to determine the speed of air masses and fronts; to determine whether an individual pressure area is deepening or becoming shallow and whether a front is increasing or decreasing in intensity. 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 a synoptic picture of conditions in the atmosphere at a given time.
All students of geography should be able 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 climatic 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 30-day outlooks are based upon an analysis of the upper air levels with often set the stage for the development of air masses, fronts, and storms. Considerable effort is being exerted today to achieve more accurate weather predictions. With the use of electronic instruments and earth satellites, enormous gains have taken place recently in identifying and tracking storms over regions which have but few meteorological stations. Extensive experiments are also in progress for weather modification studies. But the limitations of weather modification have prevented meteorological results except in the seeding of super-cooled, upslope mountainous winds which have produced additional orographical precipitation on the windward side of mountain ranges. Nevertheless, they have provided a clearer understanding of the fundamentals of weather elements.
1 One characteristic of weather maps not mentioned by the author in this passage is .
A wind speed
B thermal changes
C fronts
D barometric pressure
2 The thirty-day forecast is determined by examining .
A upper air levels
B satellite reports
C changing fronts
D daily air maps
3 The observation of weather conditions by satellites is advantageous because it .
A gives the scientist information not obtained readily otherwise
B enables man to alter the weather
C uses electronic instruments
D is modern
4 A weather map is synoptic because it .
A summarizes a great deal of information
B can be interpreted accurately
C appears daily
D shows changing fronts
5 At the present time, experiments are being conducted in .
A 30-day outlook
B controlling storms
C satellites
D manipulating weather
参考答案
1. B2. A3. D4. A5. D
英语四级顺利过关常考句型(2)
英语四级写作方法与技巧作文加分词汇
怎样看待大学生沉迷网络的问题
介绍借助普遍的观点开始作文的句型
大学生的极生活方式消
运用复杂句型结构和高级词汇得高分
英语四级写作方法与技巧高分句式
英语四级写作方法与技巧作文中间
英语四级顺利过关常考句型(4)
写信对朋友进入大学表示祝贺和建议
Food Contamination
英语四级顺利过关常考句型(1)
专家重点推荐英语四级写作经典句型
英语四级写作方法与技巧举例法
盘点英语作文开头句型7大写法
针对问题开门见山的作文开篇句型
英语四级写作方法与技巧结尾
知识还能改变命运吗
英语四级作文万能句,英语作文万能替换句专题
The Necessity of Examination
大学英语四级写作的突出问题
英语四级顺利过关常考句型(3)
我们对垃圾的爱之垃圾成堆
双学士学位的现象和我的看法
最新四级阅读考试必备范文广告牌的兴起
On College Students Doing Sales Promotion
作文高频基本句式
英语四级写作方法与技巧作文新动向与新挑战
英语四级写作方法与技巧作文开头
引出不同观点的万能句
不限 |
英语教案 |
英语课件 |
英语试题 |
不限 |
不限 |
上册 |
下册 |
不限 |