| CEOS EO HANDBOOK – MEASUREMENT CATEGORIES
|
|
Measurements > Atmosphere
EO Handbook summary: click here  | Measurements of atmosphere include a number of parameters covering temperature, humidity, component gas concentration, clouds, and radiation. | |
| Measurement | Description | Timeline |
| Aerosols | Aerosols are tiny particles suspended in the air, with the majority derived from natural phenomena such as volcanic eruptions, thought it is estimated that some 10–20% are generated by human activities such as burning of fossil fuels. The majority of aerosols form a thin haze in the lower atmosphere and are regularly washed out by precipitation, with the remainder found in the stratosphere where they can remain for many months or years. |  |
| Atmospheric Humidity Fields | The observations for water vapour (atmospheric humidity) are a core requirement for weather forecasting and are largely dealt with in the framework of the Coordinating Group for Meteorological Satellites (CGMS). The 3-dimensional field of humidity is a key variable for global and regional weather prediction (NWP) models that are used to produce short- and medium-range forecasts of the state of the troposphere and lower stratosphere. | |
| Atmospheric Temperature Fields | With humidity, atmospheric temperature profile data are a core requirement for weather forecasting and are coordinated within the framework of CGMS (The Coordination Group for Meteorological Satellites). The data are used for numerical weather prediction (NWP), for monitoring inter-annual global temperature changes, for identifying correlations between atmospheric parameters and climatic behaviour, and for validating global models of the atmosphere. | |
| Atmospheric Winds | Measurements of atmospheric winds are of primary importance to weather forecasting, and as a variable in the study of global climate change. Upper air wind speed and direction is a basic element of the climate system that influences many other variables. | |
| Cloud particle properties and profile | A key to climate modelling is to observe and understand the global distribution of clouds, their physical properties, such as thickness and droplet size. Whether a particular cloud will heat or cool the Earth’s surface depends on the cloud’s radiating temperature – and thus its height – and on its albedo for both visible and infrared radiation, which depends on the number and details of the cloud properties. | |
| Cloud type, amount and cloud top temperature | The study of clouds, their location and characteristics, plays a key role in the understanding of climate change. Low, thick clouds primarily reflect solar radiation and cool the surface of the Earth. High, thin clouds primarily transmit incoming solar radiation, but at the same time they trap some of the outgoing infrared radiation emitted by the Earth and radiate it back downward, thereby warming the surface. Parameters include temperature and moisture profiles, fractional cloud cover, cloud top height, cloud top pressure, surface temperature and surface emissivity. | |
| Lightning Detection | Measurement type description needs to be added to the MIM DB. | |
| Liquid water and precipitation rate | Water forms one of the most important constituents of the Earth’s atmosphere and is essential for human existence. The global water cycle is at the heart of the Earth’s climate system, and better predictions of its behaviour are needed for monitoring climate variability and change, weather forecasting and sustainable development of the world’s water resources. | |
| Ozone | Ozone (O3) is a relatively unstable molecule, and although it represents only a tiny fraction of the atmosphere, it is crucial for life on Earth. Depending on its location, ozone can protect or harm life on Earth. Most ozone resides in the stratosphere, where it acts as a shield to protect the surface from the Sun’s harmful ultraviolet radiation. In the troposphere, ozone is a harmful pollutant which causes damage to lung tissue and plants. | |
| Radiation budget | The Earth’s radiation budget is the balance within the climate system between the energy that reaches the Earth from the Sun and the energy that returns from Earth to space. The goal of such measurements is to determine the amount of energy emitted and reflected by the Earth. This is necessary to understand the processes by which the atmosphere, land and oceans transfer energy to achieve global radiative equilibrium, which in turn is necessary to simulate and predict climate. | |
| Trace gases (excluding ozone) | Trace gases other than ozone may be divided into three categories: greenhouse gases affecting climate change; chemically aggressive gases affecting the environment (including the biosphere); and, gases and radicals impacting on the ozone cycle, thereby affecting both climate and environment. Measurements include the concentration of trace gasses, column totals and integrated column measurements, and profiles of gas concentration. | |
|
|
|