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Paleoclimatology
Paleoclimatology (American and British English spelling differences, British spelling, palaeoclimatology) is the study of climates for which direct measurements were not taken. As instrumental records only span a tiny part of Earth's history, the reconstruction of ancient climate is important to understand natural variation and the evolution of the current climate. Paleoclimatology uses a variety of proxy (climate), proxy methods from Earth science, Earth and list of life sciences, life sciences to obtain data previously preserved within Rock (geology), rocks, sediments, boreholes, ice sheets, tree rings, corals, mollusc shell, shells, and Micropaleontology#Microfossils, microfossils. Combined with techniques to date the proxies, the paleoclimate records are used to determine the past states of Earth's atmosphere. The scientific field of paleoclimatology came to maturity in the 20th century. Notable periods studied by paleoclimatologists are the frequent glacial period, glaciatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Climate
Climate is the long-term weather pattern in an area, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteorological variables that are commonly measured are temperature, humidity, atmospheric pressure, wind, and precipitation. In a broader sense, climate is the state of the components of the climate system, including the atmosphere, hydrosphere, cryosphere, lithosphere and biosphere and the interactions between them. The climate of a location is affected by its latitude/longitude, terrain, altitude, land use and nearby water bodies and their currents. Climates can be classified according to the average and typical variables, most commonly temperature and precipitation. The most widely used classification scheme was the Köppen climate classification. The Thornthwaite system, in use since 1948, incorporates evapotranspiration along wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proxy (climate)
In the study of past climates ("paleoclimatology"), climate proxies are preserved physical characteristics of the past that stand in for direct meteorological measurements and enable scientists to reconstruct the climatic conditions over a longer fraction of the Earth's history. Reliable global records of climate only began in the 1880s, and proxies provide the only means for scientists to determine climatic patterns before record-keeping began. A large number of climate proxies have been studied from a variety of geologic contexts. Examples of proxies include stable isotope measurements from ice cores, growth rates in tree rings, species composition of sub-fossil pollen in lake sediment or foraminifera in ocean sediments, temperature profiles of boreholes, and stable isotopes and mineralogy of corals and carbonate speleothems. In each case, the proxy indicator has been influenced by a particular seasonal climate parameter (e.g., summer temperature or monsoon intensity) at the t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth's Atmosphere
The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The atmosphere of Earth protects life on Earth by creating pressure allowing for liquid water to exist on the Earth's surface, absorbing ultraviolet solar radiation, warming the surface through heat retention ( greenhouse effect), and reducing temperature extremes between day and night (the diurnal temperature variation). By mole fraction (i.e., by number of molecules), dry air contains 78.08% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide, and small amounts of other gases. Air also contains a variable amount of water vapor, on average around 1% at sea level, and 0.4% over the entire atmosphere. Air composition, temperature, and atmospheric pressure vary with altitude. Within the atmosphere, air suitable for use in photosynthesis by terrestrial plants and breathing of terrestrial animals is fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coral
Corals are marine invertebrates within the class Anthozoa of the phylum Cnidaria. They typically form compact colonies of many identical individual polyps. Coral species include the important reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton. A coral "group" is a colony of very many genetically identical polyps. Each polyp is a sac-like animal typically only a few millimeters in diameter and a few centimeters in height. A set of tentacles surround a central mouth opening. Each polyp excretes an exoskeleton near the base. Over many generations, the colony thus creates a skeleton characteristic of the species which can measure up to several meters in size. Individual colonies grow by asexual reproduction of polyps. Corals also breed sexually by spawning: polyps of the same species release gametes simultaneously overnight, often around a full moon. Fertilized eggs form planulae, a mobile early form of the coral polyp which, whe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
History Of China
The earliest known written records of the history of China date from as early as 1250 BC, from the Shang dynasty (c. 1600–1046 BC), during the reign of king Wu Ding. Ancient historical texts such as the '' Book of Documents'' (early chapters, 11th century BC), the '' Bamboo Annals'' (c. 296 BC) and the ''Records of the Grand Historian'' (c. 91 BC) describe a Xia dynasty before the Shang, but no writing is known from the period, and Shang writings do not indicate the existence of the Xia. The Shang ruled in the Yellow River valley, which is commonly held to be the cradle of Chinese civilization. However, Neolithic civilizations originated at various cultural centers along both the Yellow River and Yangtze River. These Yellow River and Yangtze civilizations arose millennia before the Shang. With thousands of years of continuous history, China is among the world's oldest civilizations and is regarded as one of the cradles of civilization. The Zhou dynasty (1046–256 BC) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesopotamia
Mesopotamia ''Mesopotamíā''; ar, بِلَاد ٱلرَّافِدَيْن or ; syc, ܐܪܡ ܢܗܪ̈ܝܢ, or , ) is a historical region of Western Asia situated within the Tigris–Euphrates river system, in the northern part of the Fertile Crescent. Today, Mesopotamia occupies modern Iraq. In the broader sense, the historical region included present-day Iraq and Kuwait and parts of present-day Iran, Syria and Turkey. The Sumerians and Akkadians (including Assyrians and Babylonians) originating from different areas in present-day Iraq, dominated Mesopotamia from the beginning of written history () to the fall of Babylon in 539 BC, when it was conquered by the Achaemenid Empire. It fell to Alexander the Great in 332 BC, and after his death, it became part of the Greek Seleucid Empire. Later the Arameans dominated major parts of Mesopotamia (). Mesopotamia is the site of the earliest developments of the Neolithic Revolution from around 10,000 BC. It ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indus Valley Civilisation
The Indus Valley Civilisation (IVC), also known as the Indus Civilisation was a Bronze Age civilisation in the northwestern regions of South Asia, lasting from 3300 BCE to 1300 BCE, and in its mature form 2600 BCE to 1900 BCE. Together with ancient Egypt and Mesopotamia, it was one of three early civilisations of the Near East and South Asia, and of the three, the most widespread. Its sites spanned an area from much of Pakistan, to northeast Afghanistan, and northwestern India. The civilisation flourished both in the alluvial plain of the Indus River, which flows through the length of Pakistan, and along a system of perennial monsoon-fed rivers that once coursed in the vicinity of the Ghaggar-Hakra, a seasonal river in northwest India and eastern Pakistan. The term ''Harappan'' is sometimes applied to the Indus civilisation after its type site Harappa, the first to be excavated early in the 20th century in what was then the Punjab province ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American And British English Spelling Differences
Despite the various English dialects spoken from country to country and within different regions of the same country, there are only slight regional variations in English orthography, the two most notable variations being British and American spelling. Many of the differences between American and British English date back to a time before spelling standards were developed. For instance, some spellings seen as "American" today were once commonly used in Britain, and some spellings seen as "British" were once commonly used in the United States. A "British standard" began to emerge following the 1755 publication of Samuel Johnson's '' A Dictionary of the English Language'', and an "American standard" started following the work of Noah Webster and, in particular, his '' An American Dictionary of the English Language'', first published in 1828. Webster's efforts at spelling reform were somewhat effective in his native country, resulting in certain well-known patterns of spelli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Robert Hooke
Robert Hooke FRS (; 18 July 16353 March 1703) was an English polymath active as a scientist, natural philosopher and architect, who is credited to be one of two scientists to discover microorganisms in 1665 using a compound microscope that he built himself, the other scientist being Antoni van Leeuwenhoek in 1676. An impoverished scientific inquirer in young adulthood, he found wealth and esteem by performing over half of the architectural surveys after London's great fire of 1666. Hooke was also a member of the Royal Society and since 1662 was its curator of experiments. Hooke was also Professor of Geometry at Gresham College. As an assistant to physical scientist Robert Boyle, Hooke built the vacuum pumps used in Boyle's experiments on gas law, and himself conducted experiments. In 1673, Hooke built the earliest Gregorian telescope, and then he observed the rotations of the planets Mars and Jupiter. Hooke's 1665 book '' Micrographia'', in which he coined the term " cell" ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Climate Change
In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to Earth's climate. The current rise in global average temperature is more rapid than previous changes, and is primarily caused by humans burning fossil fuels. Fossil fuel use, deforestation, and some agricultural and industrial practices increase greenhouse gases, notably carbon dioxide and methane. Greenhouse gases absorb some of the heat that the Earth radiates after it warms from sunlight. Larger amounts of these gases trap more heat in Earth's lower atmosphere, causing global warming. Due to climate change, deserts are expanding, while heat waves and wildfires are becoming more common. Increased warming in the Arctic has contributed to melting permafrost, glacial retreat and sea ice loss. Higher temperatures are also causing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greenhouse Effect
The greenhouse effect is a process that occurs when energy from a planet's host star goes through the planet's atmosphere and heats the planet's surface, but greenhouse gases in the atmosphere prevent some of the heat from returning directly to space, resulting in a warmer planet. Earth's natural greenhouse effect makes life as we know it possible and carbon dioxide plays a significant role in providing for the relatively high temperature on Earth. The greenhouse effect is a process by which thermal radiation from a planetary atmosphere warms the planet's surface beyond the temperature it would have in the absence of its atmosphere.A concise description of the greenhouse effect is given in the ''Intergovernmental Panel on Climate Change Fourth Assessment Report,'' "What is the Greenhouse Effect?FAQ 1.3 – AR4 WGI Chapter 1: Historical Overview of Climate Change Science, IPCC Fourth Assessment Report, Chapter 1, p. 115: "To balance the absorbed incoming olarenergy, the Earth m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
