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Topic Review
Trough (Meteorology)
A trough is an elongated region of relatively low atmospheric pressure without a closed isobaric contour that would define it as a low pressure area. Since low pressure implies a low height on a pressure surface, troughs and ridges refer to features in an identical sense as those on a topographic map. Troughs may be at the surface, or aloft. Near-surface troughs sometimes mark a weather front associated with clouds, showers, and a wind direction shift. Upper-level troughs in the jet stream (as shown in diagram) reflect cyclonic filaments of vorticity. Their motion induces upper-level wind divergence, lifting and cooling the air ahead (downstream) of the trough and helping to produce cloudy and rain conditions there. Unlike fronts, there is not a universal symbol for a trough on a surface weather analysis chart. The weather charts in some countries or regions mark troughs by a line. In the United States, a trough may be marked as a dashed line or bold line. In the UK, Hong Kong and Fiji, it is represented by a bold line extended from a low pressure center or between two low pressure centers; in Macau and Australia, it is a dashed line. If they are not marked, troughs may still be identified as an extension of isobars away from a low pressure center.
  • 2.2K
  • 14 Oct 2022
Topic Review
Younger Dryas
The Younger Dryas (around 12,900 to 11,700 years BP) was a return to glacial conditions after the Late Glacial Interstadial, which temporarily reversed the gradual climatic warming after the Last Glacial Maximum (LGM) started receding around 20,000 BP. It is named after an indicator genus, the alpine-tundra wildflower Dryas octopetala, as its leaves are occasionally abundant in late glacial, often minerogenic-rich sediments, such as the lake sediments of Scandinavia. Physical evidence of a sharp decline in temperature over most of the Northern Hemisphere has been discovered by geological research. This temperature change occurred at the end of what the earth sciences refer to as the Pleistocene epoch and immediately before the current, warmer Holocene epoch. In archaeology, this time frame coincides with the final stages of the Upper Paleolithic in many areas. The Younger Dryas was the most recent and longest of several interruptions to the gradual warming of the Earth's climate since the severe LGM, about 27,000 to 24,000 years BP. The change was relatively sudden, taking place in decades, and it resulted in a decline of temperatures in Greenland by 4 to 10°C (7.2 to 18°F) and advances of glaciers and drier conditions, over much of the temperate Northern Hemisphere. It is thought to have been caused by a decline in the strength of the Atlantic meridional overturning circulation, which transports warm water from the Equator towards the North Pole, in turn thought to have been caused by an influx of fresh, cold water from North America to the Atlantic. The Younger Dryas was a period of climatic change, but the effects were complex and variable. In the Southern Hemisphere and some areas of the Northern Hemisphere, such as southeastern North America, a slight warming occurred.
  • 3.4K
  • 14 Oct 2022
Topic Review
De-Carbonization of Zhejiang Province by Nature
The increasing emission of CO2 causes global warming and ocean acidification, imposing damages on the global ecosystem. With the continuous development of industry, fossil CO2 emissions have increased rapidly, and global fossil CO2 emissions have reached 36.4 Gt yr−1 in 2021. In response to the increasing global warming, climate goals, i.e., “zero carbon” and “carbon neutral”, have been proposed by more than 130 countries in the world while 66 of them have reached a consensus on the net-zero target. 
  • 463
  • 14 Oct 2022
Topic Review
Impact of Cyanobacteria Blooms on Environment and Health
Cyanobacteria blooms are a global aquatic environment problem. Due to global warming and water eutrophication, the surface cyanobacteria accumulate in a certain area to form cyanobacteria blooms driven by wind. Cyanobacteria blooms change the physical and chemical properties of water and cause pollution. Moreover, cyanobacteria release organic matter, N (nitrogen) and P (phosphorus) into the water during their apoptosis, accelerating the eutrophication of the water, threatening aquatic flora and fauna, and affecting the community structure and abundance of microorganisms in the water. Simultaneously, toxins and carcinogens released from cyanobacteria can be enriched through the food chain/web, endangering human health. 
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  • 14 Oct 2022
Topic Review
Aerobic Bioreactor Systems Treating Agro-Industrial Wastewaters
The thriving agro-industry sector accounts for an essential part of the global gross domestic product, as the need for food and feed production is rising. However, the industrial processing of agricultural products requires the use of water at all stages, which consequently leads to the production of vast amounts of effluents with diverse characteristics, which contain a significantly elevated organic content. This fact reinforces the need for action to control and minimize the environmental impact of the produced wastewater, and activated sludge systems constitute a highly reliable solution for its treatment.
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  • 14 Oct 2022
Topic Review
St. Mary's Islands
St. Mary's Islands, also known as Coconut Island and Thonsepar, are a set of four small islands in the Arabian Sea off the coast of Malpe in Udipi, Karnataka, India. They are known for their distinctive geological formation of columnar rhyolitic lava (pictured). Scientific studies indicate that the basalt of the St. Mary's Islands was formed by sub-aerial subvolcanic activity, because at that time Madagascar was attached to India. The rifting of Madagascar took place around 88 million years ago. Columnar rhyolite Lava here form one of the four geological monuments in Karnataka state, one of the 34 National Geological Monuments of India declared by the Geological Survey of India in 2016 for their protection, maintenance, promotion and enhancement of geotourism. The monument is considered an important site for "Geo Tourism".
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Topic Review
Greenhouse Gas Emissions Accounting
Greenhouse gas emissions accounting is measuring the amount of greenhouse gases (GHG) emitted during a given period of time by a polity, usually a country but sometimes a region or city. Such measures are used to conduct climate science and climate policy. There are two main, conflicting ways of measuring GHG emissions: production-based (also known as territorial-based) and consumption-based. Production-based emissions take place “within national territory and offshore areas over which the country has jurisdiction”. Consumption-based emissions take into account the effects of trade, encompassing the emissions from domestic final consumption and those caused by the production of its imports. From the perspective of trade, consumption-based emissions accounting is thus the reverse of production-based emissions accounting, which includes exports but excludes imports (Table 1). The choice of accounting method can have very important effects on policymaking, as each measure can generate a very different result. Thus, different values for a National greenhouse gas Emissions Inventory (NEI) could result in a country choosing different optimal mitigation activities, the wrong choice based on wrong information being potentially damaging. The application of production-based emissions accounting is currently favoured in policy terms as it is easier to measure, although much of the scientific literature favours consumption-based accounting. The former method is criticised in the literature principally for its inability to allocate emissions embodied in international trade/transportation and the potential for carbon leakage. Almost all countries in the world are parties to the Paris Agreement, which requires them to provide regular production-based GHG emissions inventories to the United Nations Framework Convention on Climate Change (UNFCCC), in order to track both countries achievement of their nationally determined contributions and climate policies as well as regional climate policies such as the EU Emissions Trading Scheme (ETS), and the world's progress in limiting global warming. Under an earlier UNFCCC agreement greenhouse gas emissions by Turkey and greenhouse gas emissions by the United States will continue to be inventoried even if they are not parties to the Paris Agreement.
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  • 13 Oct 2022
Topic Review
September 2019 Climate Strikes
The September 2019 climate strikes, also known as the Global Week for Future, were a series of international strikes and protests to demand action be taken to address climate change, which took place from 20–27 September. The strikes' key dates were 20 September, which was three days before the United Nations Climate Summit, and 27 September. The protests took place across 4,500 locations in 150 countries. The event is a part of the school strike for climate movement, inspired by Swedish climate activist Greta Thunberg. The Guardian reported that roughly 6 million people participated in the events, whilst 350.org—a group that organised many of the protests—claim that 7.6 million people participated. The 20 September protests were likely the largest climate strikes in world history. Organisers reported that over 4 million people participated in strikes worldwide, including 1.4 million participants in Germany. An estimated 300,000 protesters took part in Australian strikes, a further 300,000 people joined UK protests and protesters in New York—where Greta Thunberg delivered a speech—numbered roughly 250,000. More than 2,000 scientists in 40 countries pledged to support the strikes. A second wave of protests took place on 27 September, in which an estimated 2 million people took part in over 2,400 protests. There were reported figures of one million protesters in Italy, and 170,000 people in New Zealand. In Montreal, where Greta Thunberg spoke, the Montreal school board cancelled classes for 114,000 of its students. Hundreds of thousands of people, including several federal party leaders, joined the march in Montreal.
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  • 13 Oct 2022
Topic Review
Climate of Ancient Rome
The climate of Ancient Rome varied throughout the existence of that civilization. In the first half of the 1st millennium BC the climate of Italy was more humid and cool than now and the presently arid south saw more precipitation. The northern regions were situated in the temperate climate zone, while the rest of Italy was in the subtropics, having a warm and mild climate. During the annual melt of the mountain snow even small rivers would overflow, swamping the terrain (Tuscany and the Pontine Marshes were deemed impassable in antiquity). The existence of Roman civilization (including the Eastern Roman Empire) spanned three climatological periods: Early Subatlantic (900 BC–175 AD), Mid-Subatlantic (175–750) and Late Subatlantic (since 750). The written, archaeological and natural-scientific proxy evidence independently but consistently shows that during the period of the Roman Empire's maximum expansion and final crisis, the climate underwent changes. The Empire's greatest extent under Trajan coincided with the Roman climatic optimum. The climate change occurred at different rates, from apparent near stasis during the early Empire to rapid fluctuations during the late Empire. Still, there is some controversy in the notion of a generally moister period in the eastern Mediterranean in c. 1 AD–600 AD due to conflicting publications.
  • 1.5K
  • 13 Oct 2022
Topic Review
Lignocellulosic Biomass as a Renewable Source
Lignocellulosic biomass is the primary structural component of plant matter and is mostly inedible, generally referring to organic materials such as wood, grass, and agricultural crop residues. Biomass is a plentiful and carbon-neutral renewable energy source that may be used to create platform chemicals and fuels, especially considering that up to 75% of initial energy can be converted into biofuels.
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