This preview shows pages 1–3. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: This document last updated on 18-Oct-2011 EENS 2040 Natural Disasters Tulane University Prof. Stephen A. Nelson The Ocean-Atmosphere System The Ocean-Atmosphere System The oceans and the atmosphere are the two large reservoirs of water in the Earth's hydrologic cycle. The two systems are complexly linked to one another and are responsible for Earth's weather and climate. The oceans help to regulate temperature in the lower part of the atmosphere. The atmosphere is in large part responsible for the circulation of ocean water through waves and currents. In this section we first look at how the atmosphere controls weather and climate, and we will explore some the introductory material necessary to understand our upcoming lectures on severe weather. Weather and Climate Weather is the condition of the atmosphere at a particular time and place. It refers to such conditions of the local atmosphere as temperature, atmospheric pressure, humidity (the amount of water contained in the atmosphere), precipitation (rain, snow, sleet, & hail), and wind velocity. Because the amount of heat in the atmosphere varies with location above the Earth's surface, and because differing amounts of heat in different parts of the atmosphere control atmospheric circulation, the atmosphere is in constant motion. Thus, weather is continually changing in a complex and dynamic manner. Climate refers to the average weather characteristics of a given region. Climate, although it does change over longer periods of geologic time, is more stable over short periods of time like years and centuries. The fact that the Earth has undergone fluctuation between ice ages and warmer periods in the recent past (the last ice age ended about 10,000 years ago) is testament to the fact that climate throughout the world as has been changing through time. The Earth's weather and climate system represent complex interactions between the oceans, the land, the sun, and the atmosphere. That these interactions are complex is evidence by the difficulty meteorologists have in predicting weather on a daily basis. Understanding climate change is even more difficult because humans have not been around long enough to record data on the long term effects of these processes. Still, we do know that the main energy source for changing weather patterns and climate is solar energy from the Sun. The Atmosphere Earth's atmosphere consists of a mixture of Nitrogen (N 2 ) and Oxygen (O 2 ). At the Earth's surface, dry air is composed of about 79% Nitrogen, 20% Oxygen, and 1% Argon. It can also contain up to 4% water vapor at saturation, but saturation depends on temperature. Ocean Atmosphere System 10/18/2011 Page 1 of 16 Relative humidity is the term used to describe saturation with water vapor. When the relative humidity is 100%, the atmosphere is saturated with respect to water vapor, and precipitation results. Other gases occur in the atmosphere in small amounts....
View Full Document
This note was uploaded on 02/01/2012 for the course EENS 2040 taught by Professor Nelson during the Fall '11 term at Tulane.
- Fall '11