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XCO2
XCO2 is the column-averaged of carbon dioxide in the atmosphere, represented in parts per million (ppm). Rather than taking a single observation at the surface, an integration of atmospheric CO2 above a specific location is observed. The 'X' refers to the observation taking place from a satellite platform. CO2 observing satellites cannot observe green house gasses directly, but instead average the entire atmospheric column of CO2. These estimates from satellites need ground truthing to ensure that XCO2 retrievals are accurate, with an average accuracy from OCO 2 and GOSAT of 0.267 ± 1.56 ppm between September 2014 to December 2016. The largest recorded value XCO2 was recorded during May 2018 over the Northern Hemisphere, with a value of approximately 410 ppm. These values have been increasing steadily over recent years. Space-based CO2 measurements are used for climate-level scientific studies such as a further understanding of the El Niño–Southern Oscillation S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PCO2
''p''CO2, pCO2, or P_\ceis the partial pressure of carbon dioxide (CO2), often used in reference to blood but also used in meteorology, climate science, oceanography, and limnology to describe the fractional pressure of CO2 as a function of its concentration in gas or dissolved phases. The units of ''p''CO2 are mmHg, atm, torr, Pa, or any other standard unit of atmospheric pressure. The ''p''CO2 of Earth's atmosphere has risen from approximately 280 ppm (parts-per-million) to a mean 2019 value of 409.8 ppm as a result of anthropogenic release of carbon dioxide from fossil fuel burning. This is the highest atmospheric concentration to have existed on Earth for at least the last 800,000 years. Medicine In medicine, the partial pressure of carbon dioxide in arterial blood is called P_ or PaCO2. Measurement of P_ in the systemic circulation indicates the effectiveness of ventilation at the lungs' alveoli, given the diffusing capacity of the gas. It is a good indicator ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon Dioxide
Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transparent to visible light but absorbs infrared radiation, acting as a greenhouse gas. It is a trace gas in Earth's atmosphere at 421 parts per million (ppm), or about 0.04% by volume (as of May 2022), having risen from pre-industrial levels of 280 ppm. Burning fossil fuels is the primary cause of these increased CO2 concentrations and also the primary cause of climate change.IPCC (2022Summary for policy makersiClimate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA Carbon dioxide is soluble in water and is found in groundwater, lakes, i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parts Per Million
In science and engineering, the parts-per notation is a set of pseudo-units to describe small values of miscellaneous dimensionless quantities, e.g. mole fraction or mass fraction. Since these fractions are quantity-per-quantity measures, they are pure numbers with no associated units of measurement. Commonly used are parts-per-million (ppm, ), parts-per-billion (ppb, ), parts-per-trillion (ppt, ) and parts-per-quadrillion (ppq, ). This notation is not part of the International System of Units (SI) system and its meaning is ambiguous. Overview Parts-per notation is often used describing dilute solutions in chemistry, for instance, the relative abundance of dissolved minerals or pollutants in water. The quantity "1 ppm" can be used for a mass fraction if a water-borne pollutant is present at one-millionth of a gram per gram of sample solution. When working with aqueous solutions, it is common to assume that the density of water is 1.00 g/mL. Therefore, it is common to e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Satellite
A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotope thermoelectric generators (RTGs). Most satellites also have a method of communication to ground stations, called transponders. Many satellites use a standardized bus to save cost and work, the most popular of which is small CubeSats. Similar satellites can work together as a group, forming constellations. Because of the high launch cost to space, satellites are designed to be as lightweight and robust as possible. Most communication satellites are radio relay stations in orbit and carry dozens of transponders, each with a bandwidth of tens of megahertz. Satellites are placed from the surface to orbit by launch vehicles, high enough to avoid orbital decay by the atmosphere. Satellites can then change or maintain the orbit by pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space-based Measurements Of Carbon Dioxide
Space-based measurements of carbon dioxide () are used to help answer questions about Earth's carbon cycle. There are a variety of active and planned instruments for measuring carbon dioxide in Earth's atmosphere from space. The first satellite mission designed to measure was the Interferometric Monitor for Greenhouse Gases (IMG) on board the ADEOS I satellite in 1996. This mission lasted less than a year. Since then, additional space-based measurements have begun, including those from two high-precision (better than 0.3% or 1 ppm) satellites ( GOSAT and OCO-2). Different instrument designs may reflect different primary missions. Purposes and highlights of findings There are outstanding questions in carbon cycle science that satellite observations can help answer. The Earth system absorbs about half of all anthropogenic emissions. However, it is unclear exactly how this uptake is partitioned to different regions across the globe. It is also uncertain how different re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Green House Gasses
A greenhouse gas (GHG or GhG) is a gas that absorbs and emits radiant energy within the thermal infrared range, causing the greenhouse effect. The primary greenhouse gases in Earth's atmosphere are water vapor (), carbon dioxide (), methane (), nitrous oxide (), and ozone (). Without greenhouse gases, the average temperature of Earth's surface would be about , rather than the present average of . The atmospheres of Venus, Mars and Titan also contain greenhouse gases. Human activities since the beginning of the Industrial Revolution (around 1750) have increased the atmospheric concentration of carbon dioxide by over 50%, from 280 ppm in 1750 to 421 ppm in 2022. The last time the atmospheric concentration of carbon dioxide was this high was over 3 million years ago. This increase has occurred despite the absorption of more than half of the emissions by various natural carbon sinks in the carbon cycle. At current greenhouse gas emission rates, temperature ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ground Truth
Ground truth is information that is known to be real or true, provided by direct observation and measurement (i.e. empirical evidence) as opposed to information provided by inference. Etymology The ''Oxford English Dictionary'' (s.v. "ground truth") records the use of the word "Groundtruth" in the sense of a "fundamental truth" from Henry Ellison's poem "The Siberian Exile's Tale", published in 1833. Statistics and machine learning "Ground truth" may be seen as a conceptual term relative to the knowledge of the truth concerning a specific question. It is the ideal expected result. This is used in statistical models to prove or disprove research hypotheses. The term "ground truthing" refers to the process of gathering the proper objective (provable) data for this test. Compare with gold standard. For example, suppose we are testing a stereo vision system to see how well it can estimate 3D positions. The "ground truth" might be the positions given by a laser rangefinder whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbiting Carbon Observatory 2
Orbiting Carbon Observatory-2 (OCO-2) is an American environmental science satellite which launched on 2 July 2014. A NASA mission, it is a replacement for the Orbiting Carbon Observatory which was lost in a launch failure in 2009. It is the second successful high-precision (better than 0.3%) observing satellite, after GOSAT. Mission overview The OCO-2 satellite was built by Orbital Sciences Corporation, based around the LEOStar-2 bus. The spacecraft is being used to study carbon dioxide concentrations and distributions in the atmosphere. OCO-2 was ordered after the original OCO spacecraft failed to achieve orbit. During the first satellite's launch atop a Taurus-XL in February 2009, the payload fairing failed to separate from around the spacecraft and the rocket did not have sufficient power to enter orbit with its additional mass. Although a Taurus launch was initially contracted for the reflight, the launch contract was cancelled after the same malfunction occurred on the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greenhouse Gases Observing Satellite
The Greenhouse Gases Observing Satellite (GOSAT''), also known as , is an Earth observation satellite and the world's first satellite dedicated to greenhouse gas monitoring. It measures the densities of carbon dioxide and methane from 56,000 locations on the Earth's atmosphere. The GOSAT was developed by the Japan Aerospace Exploration Agency (JAXA) and launched on 23 January 2009, from the Tanegashima Space Center. Japan's Ministry of the Environment, and the National Institute for Environmental Studies (NIES) use the data to track gases causing the greenhouse effect, and share the data with NASA and other international scientific organizations. Launch GOSAT was launched along with seven other piggyback probes using the H-IIA, Japan's primary large-scale expendable launch system, at 3:54 am on 23 January 2009 UTC on Tanegashima, a small island in southern Japan, after a two-day delay due to unfavourable weather. At approximately 16 minutes after liftoff, the separa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
El Niño–Southern Oscillation
El Niño–Southern Oscillation (ENSO) is an irregular periodic variation in winds and sea surface temperatures over the tropical eastern Pacific Ocean, affecting the climate of much of the tropics and subtropics. The warming phase of the sea temperature is known as ''El Niño'' and the cooling phase as ''La Niña''. The ''Southern Oscillation'' is the accompanying atmospheric component, coupled with the sea temperature change: ''El Niño'' is accompanied by high air surface pressure in the tropical western Pacific and ''La Niña'' with low air surface pressure there. The two periods last several months each and typically occur every few years with varying intensity per period. The two phases relate to the Walker circulation, which was discovered by Gilbert Walker during the early twentieth century. The Walker circulation is caused by the pressure gradient force that results from a high-pressure area over the eastern Pacific Ocean, and a low-pressure system over Indonesia. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon Dioxide In Earth's Atmosphere
Carbon dioxide in Earth's atmosphere is a trace gas that plays an integral part in the greenhouse effect, carbon cycle, photosynthesis and oceanic carbon cycle. It is one of several greenhouse gases in Earth's atmosphere that are contributing to climate change due to increasing emissions of greenhouse gases from human activities. The current global average concentration of CO2 in the atmosphere is 421 ppm as of May 2022. This is an increase of 50% since the start of the Industrial Revolution, up from 280 ppm during the 10,000 years to the mid-18th century. The increase is due to human activity. Burning fossil fuels is the main cause of these increased CO2 concentrations and also the main cause of climate change.IPCC (2022Summary for policy makersiClimate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change Cambridge University Press, Cambridge, United Kingdom and New ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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