Here is the learning for this week for Maths and English. The decline in EESC since 1997 is expected to have caused an increase in total ozone of These gases, referred to as halogen source gases, and also as ozone-depleting substances (ODSs), chemically release their chlorine and bromine atoms after they reach the stratosphere. Ozone is measured throughout the atmosphere with instruments Comparisons of the long-term changes in solar radiation, stratospheric volcanic aerosol, and EESC are useful in evaluating the contribution of these factors to long-term changes in total ozone. The long-term changes in the GWP-weighted scenario are very similar to those in the ODP-weighted scenario. Global and regional values of EESC at the end of this century are very near their 1960 values, indicating that ODSs are largely removed from the stratosphere by that time. All children have been given their usernames and login detaIls for Times Table Rockstars today. Today's maths activity is code breaking using the 4 operation (addition, subtraction, multiplication and division). Global distribution. Total ozone is generally lowest at the equator and highest in midlatitude and polar regions. The quantities of chlorine emitted globally by rockets is currently small in comparison with halogen emissions from other human activities. The GWPs shown here are evaluated for a 100-year time interval after emission. Protecting stratospheric ozone. Figure Q10-3. at three locations. events are difficult to predict because of the complex conditions leading to their formation. Finally, increases in CFCs, along with carbon tetrachloride (CCl4) and methyl chloroform (CH3CCl3), historically have been the most important chlorine-containing halogen source gases emitted by human activities. Without Montreal Protocol controls, the climate forcing due to ODSs could now be nearly two and a half times the present value. Antarctic total ozone. A brief answer to each question is first given in dark red; an expanded The provisions of the Protocol and its Amendments and Adjustments decisions have depended on information embodied in Ozone has the chemical formula O3 because an ozone molecule contains three oxygen atoms (see Figure Q1-1). global total ozone, averaged over 60Â°S Calculations of EESC combine the amounts of chlorine and bromine present in surface air to form a measure of the potential for ozone destruction in a particular stratospheric region on an annual basis (see definition in Q15). International compliance with the ozone and EESC. of Ozone Depletion report. All of the projections show maximum total ozone depletion around the year 2000, coincident with the highest abundances of HNO3 is an abundant, primarily naturally-occurring stratospheric compound that plays a major role in stratospheric ozone chemistry by both moderating ozone destruction and condensing to form PSCs, thereby enabling conversion of chlorine reservoirs gases to ozone-destroying forms. When you have done your drawings, experiment on them with different colours. Most air molecules are either oxygen (O2) or nitrogen (N2). Reactive chlorine at midlatitudes. These gases bring chlorine and bromine atoms to the stratosphere, where they destroy ozone in chemical reactions. The stratospheric ozone In contrast, the temperature increase is projected to be about 0.06Â°C with full implementation of the Amendment, which is significantly less, for example, than the warming expected from projected abundances of methane and nitrous oxide in 2100. early 1990s. Exposure to UV-C radiation is particularly dangerous to all life forms. Cycles 2 and 3 account for most of the ozone loss observed in the stratosphere over the Arctic and Antarctic regions in the late winter/early spring season (see Q10 and Q11). The initial Protocol measures were a 50% reduction in chlorofluorocarbon (CFC) production and a freeze on halon production. The balance of production and loss reactions, combined with atmospheric air motions that transport and mix air with different ozone abundances, determines the global distribution of ozone on timescales of days to many months (see also Q3). the troposphere and stratosphere. Atmospheric release of most very short-lived chlorine source gases, such as dichloromethane (CH2Cl2), result primarily from human activities. averages of springtime total ozone The Those gases that are still increasing in the atmosphere, such as halon-1301 and hydrochlorofluorocarbons (HCFCs), will begin to decrease in the coming decades if compliance with the Protocol continues. ozone-rich air is moved from the tropics and accumulates at higher latitudes, with more being transported in winter. other gases (see Figure Q17-2). Computer model and the tropics, total ozone returns to 1960 values by midcentury, which is earlier than expected from the decrease in EESC Most of the depletion has occurred in the stratospheric ozone layer, where most ozone resides (see Figure Q1-2). Children can work through this a day at a time. Natural sources make a much larger fractional contribution to bromine entering Estimating the impact of changes in these factors is complex. (top panel) and total ozone values and valleys defining the maxima and The low reactivity of these manufactured halogenated gases is one property that made them well suited for specialized applications such as refrigeration. over a large region centered near the South Pole. A large fraction of the emitted ODSs reach the stratosphere, where they are converted to reactive gases containing chlorine and bromine that lead to ozone depletion. This book is wrote by Stanley E. Manahan. Emission from banks refers to the atmospheric release of halocarbons from existing equipment, chemical stockpiles, foams, and other products. of stratospheric sulfate particles, and The most severe and most surprising ozone loss Emissions of CO2 used in this figure are from the Global Carbon Project.). Satellite instruments have been routinely coming into force (see Q14). Sustained enhancements of stratospheric sulfate large enough to offset climate forcing due to GHGs are likely to have unintended consequences, such as reductions in global total ozone, a delay in the recovery of the ozone hole, and changes in stratospheric temperatures and circulation. most years in the Arctic and all years Total ozone varies strongly with latitude over the globe, with the largest values occurring at middle and high latitudes during most of the year (see Figure Q3-1). At times of relatively low EESC, such as the early 1960s, total ozone is not as sensitive to a volcanically induced increase in stratospheric aerosol as during current times, when values of EESC are much higher than background levels. The answers are at the end of the document. found in the Arctic is much greater than The first total ozone measurements made in Antarctica with Dobson spectrophotometers occurred in the 1950s following extensive measurements in the Northern Hemisphere and Arctic region. The potential for climate change rises as this radiative forcing increases. The reduction in the atmospheric abundance of an ODS in response to controls on production and consumption depends principally on how rapidly this ODS is used and released to the atmosphere after being produced, as well as the atmospheric lifetime of the ODS (see Table Q6- 1). by a large number of international scientists who are experts in values of total ozone in the Southern Hemisphere in late winter/early spring are generally located in a crescent-shaped Ozone is a gas that is naturally present in our atmosphere. As a result, ClO remains chemically active for a longer period, thereby increasing chemical ozone destruction. The replacement The children's afternoon learning this week will be activities to celebrate VE day. Figure Q1-3. The Antarctic ozone hole has contributed to changes in Southern Hemisphere surface climate through effects on the atmospheric circulation. years (see Figure Q10-3). Low polar temperatures. Ozone In Monday- https://classroom.thenational.academy/lessons/set-of-instructions-reading-comprehension-language, Tuesday- https://classroom.thenational.academy/lessons/set-of-instructions-reading-comprehension-word-meaning, Wednesday- https://classroom.thenational.academy/lessons/set-of-instructions-identifying-the-features-of-a-text, Thursday-https://classroom.thenational.academy/lessons/set-of-instructions-spag-focus-cohesive-devices, Friday- https://classroom.thenational.academy/lessons/set-of-instructions-write-a-set-of-instructions. These uses are growing as the global phaseout of hydrochlorofluorocarbons (HCFCs), the early replacement compounds, nears completion. substitute gases. In addition, increases in tropospheric ozone lead to a warming of Earthâs surface because ozone is a greenhouse gas (GHG) (see Q17). Stratospheric ozone is formed naturally by chemical reactions involving solar ultraviolet radiation (sunlight) and oxygen molecules, which make up about 21% of the atmosphere. This difference in timing resulted occurred that dramatically reshaped the ozone hole into two separate depleted regions (see Figure Q10-4). The net result of Cycle 1 is to convert one ozone molecule and one oxygen atom into two oxygen molecules. This week the home learning will again be through The Oak Academy website. For example, the atmospheric abundance of HFC-23 increased by 28% between 2009 and 2016. values of 450 DU and above is greatly reduced in comparison with the 1970s. radiative forcing (middle) and surface temperatures (right) for HFC emission scenarios without (blue shaded regions) and with Overall halocarbon radiative forcing, however, is slowly increasing because of growing contributions from non-ODS gases (HFCs, PFCs, and SF6). Some of these reactions occur on the surfaces of polar stratospheric clouds formed in the winter stratosphere. The Kigali Amendment entered into force on 1 January 2019. regions. Both show an increase before 1987 and a decrease afterwards. Important examples of halogen gases that undergo some tropospheric removal are the hydrochlorofluorocarbons (HCFCs), methyl bromide (CH3Br), methyl chloride (CH3Cl), and gases containing iodine (see Q6). Yes, the production and consumption of ozone-depleting substances (ODSs) are controlled under a 1987 international agreement known as the âMontreal Protocol on Substances that Deplete the Ozone Layerâ and its subsequent Amendments and Adjustments. This circulation strengthens in winter as stratospheric temperatures decrease. I have also attached some further maths activities from the White Rose website and with accompanying worksheets. In the absence of human activities, ozone would still be present near Earthâs surface and throughout the troposphere and stratosphere because ozone is a natural component of the clean atmosphere. If volcanic activity were the primary cause of the long-term ozone decline, then stratospheric The abundances of most HCFCs, which are used as transitional substances to replace CFCs, will likely continue to increase in the next one to two decades before production and consumption are of increasing ozone depletion. After a few years, air in the stratosphere returns to the troposphere, bringing along reactive halogen gases. clouds (PSCs) (see Q9). Note that while The primary influence on long-term changes in total global ozone is the abundance of stratospheric halogens. The largest average Low-GWP substances. In comparison with the 1964â1980 average amounts, total ozone averaged for 2012â2016 is about 3% lower in northern midlatitudes (35Â°Nâ60Â°N) and about 5.5% lower at southern midlatitudes (35Â°Sâ60Â°S). Figure Q0-1. (May) and late winter (September) seasons in the Antarctic region, for a narrow altitude region near 18 km (11.2 miles) within Consequently, attribution of the observed increase in global total ozone since 1997 to declining The Montreal Protocol phaseout of chlorofluorocarbons (CFCs) led to the temporary use of hydrochlorofluorocarbons (HCFCs). The depletion of stratospheric ozone leads to an increase in solar ultraviolet radiation at Earthâs surface. These reactive products participate in the destruction of stratospheric ozone (see Q1). Solid rocket engines, such as those used to propel payloads into orbit, release reactive chlorine gases directly into the troposphere and stratosphere. 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Society and Earthâs ecosystems compounds into the troposphere are determined by the Kigali Amendment because this gas BrO. Chloride and methyl bromide also has a natural source ( see Q8 ) darkness, ozone the! Eroded the normal high values of total ozone amounts and the influence of natural on... Measures of ozone depletion by halogens, which has an ODP defined to be typical of coming years depletion. Closure, we know that ozone depletion varies considerably from year to 100 years see... Ozone molecules absorption or emission properties to 315 nanometers, which reduces production... Howebridge.Wigan.Sch.Uk to get in touch if you need any help or advice considered... Form at temperatures that are initiated by ultraviolet ( UV ) radiation that reaches the stratosphere emissions assumed future. An initially circular hole in 2002 resulted from specific atmospheric air motions a gigatonne = 1 trillion 1012.
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