Strategies to Estimate Rainfall

Strategies to Estimate Rainfall Accurate rainfall estimation is an important and challenging task and the spatial distribution of the rain gauge is a most important factor in providing reliable areal rainfall. Modern rainfall network established to monitor hydrological features should provide the necessary and real-time information for purposes such as management of water resources, reservoir operation and flood forecast and control (Chen et al., 2008). Direct measurement of rainfall can only be achieved by rain gauges, and rain gauge networks are often installed to provide measurements that characterize the temporal and spatial variations of rainfall (Cheng et al., 2008). However, even if rain gauges are capable of providing real time rainfall information at very fine temporal resolution under the help of automatic rainfall record equipments, it is still difficult to characterize the spatial variation of rainfall without a well-designed rain gauge network in the catchment. A well designed rain gauge network with proper densities and distributions is essential to provide the valid precipitation information reflecting the spatial-temporal features in a catchment. However, most river basins of the world are poorly gauged or ungauged, and most rain gauge networks applied for hydrological purposes are largely inadequate according to the most dilute density requirements of World Meteorological Organization (WMO). WMO recommends certain densities of rain gauges to be followed for different types of basins such as 500 km2 per gauge is recommended in flat regions of temperate zones, while 25 km2 per gauge is recommended for small mountainous islands with irregular precipitation (WMO, 1994). Moreover, many non-hydrological factors considerably impacted the rain gauge network design, e.g. accessibility, cost and easiness of maintenance, topographical aspects, etc. However, many reviews have noted a marked decline in the amount of hydrometric data being collected in many parts of the world (WMO, 1996; Stokstad, 1999). The decline of hydrometric gauges exists not only in developing countries, but also happens in developed countries, e.g. the U.S. Geological Survey (USGS) network had undergone some significant reductions in the mid-1990s (Mason and York, 1997; Pyrce, 2004). This decline in hydrometric gauges means that at a time when global warming may be exacerbating weather extremes and water shortages, scientists are less able to monitor water supplies, predict droughts, and forecast floods than they were 30 years ago (Stokstad, 1999). In recent years, satellite remote sensing seems to have the potential to provide full spatial coverage of pixel rainfall estimates, however, many studies have pointed out that the satellite based rainfall data still could not provide accurate rainfall estimates to match rain gauge measurements and could not meet the requirements of hydrological modelling on daily base (e.g. Hughes, 2006; Dinku et al., 2008; Li et al., 2012, 2014). Furthermore, the satellite based precipitation data have to be calibrated with the rainfall provided by the existing rain gauges to correct the bias, and the bias correction results considerably depend on the rain gauge density and distribution. Meanwhile, the widely application of satellite based precipitation data has a consequence of the deterioration of rain gauge networks in some cases (Ali et al., 2005). Tsintikidis et al. (2002) demonstrated that even when lumped models are used for flood forecasting, a proper gauge network can significantly improve the results. Thus, to build a rain gauge network contains a minimum density of rain gauges from removing redundancy gauges which contain less information is crucial under the background of rain gauge networks deterioration. It can help to understand how the distribution of rain gauges impacts the capability of network and qualify of rainfall information provided by the network. Rain gauge network design is to analyse the number and location of stations necessary for achieving the required accuracy (Bras, 1990) and meet the objective of information provided by the network as efficiently and economically as possible (Hackett, 1966). Varies approaches using optimal selection of rainfall gauges have been applied in designing rain gauge network to yield greater precise of rainfall estimation with minimum cost. Eulogio (1998) presented an optimal network design for the estimation of areal mean rainfall events by using simulated annealing method which demonstrated that the simulated annealing algorithm of random search for optimal location of rain gauges took into account the double criterion of estimation accuracy and economic cost. Patra (2001) applied a statistical theory for rain gauge network design. The study took use the coefficient of variance and the acceptable percentage of error range to estimate the optimal number of rain gauges. St-Hilaire et al. (200 3) evaluated the impact of meteorological network density on the estimation of basin precipitation and runoff in five drainage basins in Mauricie watershed in Quebec, Canada by using Kriging method to estimate the spatial distribution and variance of rainfall. Dong et al. (2005) used variance reduction analysis method to find the appropriate quantity and location of rain gauges in Qingjiang River Basin, China for flow simulation. The study demonstrated that both cross correlation coefficient and modelling performance increase hyperbolically and level off after five rain gauges for the study area. Anctil et al. (2006) applied the method of randomly selection of rain gauges to produce subsets of rain gauge network to optimize the mean daily areal rainfall series in Bas-en-Basset watershed, southern France and using genetic algorithm to orient the rain gauge combinatorial problem toward improved forecasting performance. BÃ ¡rdossy and Das (2008) studied the influence of the spatial resolution of rainfall input on the model calibration and application by varying the distribution of the rain gauge network via External Drift Kriging method (EDK) in southwest of Germany and pointed out that the overall performance of the HBV model worsens radically with an excessive reduction of rain gauges, while there is no significant improvement of the model by increasing the number of rain gauges more than a certain threshold number. Chen et al. (2008) applied Kriging and entropy algorithm to design the rain gauge network which contains the minimum number of rain gauges and optimum spatial distribution in Taiwan, China. The summer flash rainfall exhibits particularly high spatiotemporal variability and produces severe, quick, and sharply peaked flash flooding at the study site (Desilets et al., 2008), and the monitoring of summer flash rainfall represents the most difficult and important challenge for a rain gauge network designed for flood prediction. Volkmann et al. (2010) designed rain gauge networks for flash flood prediction in semiarid catchments with complex terrain to predict flash flood. The results revealed that the multi-criteria strategy provided a robust design by which a sparse but accurate network of rain gauges could be implemented for semiarid basins such as the one studied. Precipitation gauge network structure is not only dependent on the station density; station location also plays an important role in determining whether information is gained properly. Gupta et al. (2002) and Yatheendradas et al. (2008) pointed out that rapidly changing patterns of precipitation over mountains are poorly monitored, and there are gaps in the information important to the modelling of runoff generation which makes it difficult to obtain sufficient leading time and accuracy on hydrological forecasts. Therefore, the design of hydrological measurement networks has received considerable attention in research settings. The issue of optimizing rain gauge network can be formulated as that of finding the locations of a limited number of rain gauges which provide sufficient rainfall information of both the spatial distribution and the areal mean precipitation. Thus, the main objectives of this paper are motivated to: (1) understand and quantify the variability of the precipitation in catchment scale using the Shannon’s entropy and mutual information method; (2) design and evaluate a new entropy theory based multi-criteria strategy for identifying the best locations for installation of rain gauges based on the existing dense rain gauge network; and (3) evaluate the impact of the different rain gauge networks on hydrological simulation by using the lumped and distributed hydrological models.

Masculinity in Charlotte Brontes Jane Eyre :: Charlotte Bronte Jane Eyre Essays

Masculinity in Charlotte Bronte's Jane Eyre Throughout the novel 'Jane Eyre' we meet 5 male characters. Immediately we can notice that the number of female characters outweighs the number of male characters. It feels as though BrontÃÆ'Â « is trying to tell us that overall women will come out more influential and powerful than men. Indeed power is what our male characters have in common. Their power however alters from character to character. This is the common version of masculinity portrayed by Bront throughout 'Jane Eyre'. Many men at the time of the novel were very powerful, this power varied from wealth, influential positions and even whom you knew. Women were not entitled to their own opinions and their husbands or fathers made all the decisions. Jane however defies the conventions of the time. She has her own opinions and is not prepared to take orders from the powerful men in the novel. With power comes other traits, and this is where we can differentiate between the characters. Brocklehurst and St John both have power through the position they hold (Brocklehurst being in charge of the girls' school and St John being a parson), whereas John Reed and Rochester have power through wealth. Mr Lloyd (the apothecary) is perhaps the only man in the novel without any real power and he is the only person who listens to Jane. Rochester's masculinity is the most important, as he represents the best and worst of a man. His masculinity is typical of this period and he is shown ordering Jane around, 'bring me my horse', most women were obliging to men as they were the authority in society, although Jane resents this authority and wants to do things her own way. So from this we can see that the masculinity he shows typical of the time and incredibly dominant and powerful over women in the novel, especially Jane. As the novel progresses however Rochester becomes less masculine during the fire at Thornfield he loses everything, here we can compare him to Jane because; at the beginning she too doesn't have anything. In loosing everything he loses his masculinity and power. He no longer has his house, 'I saw blackened ruins'. His house is part of his power and this is no longer there. He also looses his sight and his hand, Jane becomes his, 'eyes and hands', and Rochester is reliant on her, 'I led him out of the wet wild wood'. The role of the dominant one is reversed. Here Rochester shows very little masculinity as he is now not in charge. Jane saves Rochester but equally he saves her, from St Masculinity in Charlotte Bronte's Jane Eyre :: Charlotte Bronte Jane Eyre Essays Masculinity in Charlotte Bronte's Jane Eyre Throughout the novel 'Jane Eyre' we meet 5 male characters. Immediately we can notice that the number of female characters outweighs the number of male characters. It feels as though BrontÃÆ'Â « is trying to tell us that overall women will come out more influential and powerful than men. Indeed power is what our male characters have in common. Their power however alters from character to character. This is the common version of masculinity portrayed by Bront throughout 'Jane Eyre'. Many men at the time of the novel were very powerful, this power varied from wealth, influential positions and even whom you knew. Women were not entitled to their own opinions and their husbands or fathers made all the decisions. Jane however defies the conventions of the time. She has her own opinions and is not prepared to take orders from the powerful men in the novel. With power comes other traits, and this is where we can differentiate between the characters. Brocklehurst and St John both have power through the position they hold (Brocklehurst being in charge of the girls' school and St John being a parson), whereas John Reed and Rochester have power through wealth. Mr Lloyd (the apothecary) is perhaps the only man in the novel without any real power and he is the only person who listens to Jane. Rochester's masculinity is the most important, as he represents the best and worst of a man. His masculinity is typical of this period and he is shown ordering Jane around, 'bring me my horse', most women were obliging to men as they were the authority in society, although Jane resents this authority and wants to do things her own way. So from this we can see that the masculinity he shows typical of the time and incredibly dominant and powerful over women in the novel, especially Jane. As the novel progresses however Rochester becomes less masculine during the fire at Thornfield he loses everything, here we can compare him to Jane because; at the beginning she too doesn't have anything. In loosing everything he loses his masculinity and power. He no longer has his house, 'I saw blackened ruins'. His house is part of his power and this is no longer there. He also looses his sight and his hand, Jane becomes his, 'eyes and hands', and Rochester is reliant on her, 'I led him out of the wet wild wood'. The role of the dominant one is reversed. Here Rochester shows very little masculinity as he is now not in charge. Jane saves Rochester but equally he saves her, from St

Does UK Public transport live up to expectations? :: Business Management Studies

Does UK Public transport live up to expectations? Introduction Public transportation has always been a key issue to the government by trying to promote public transport more than using a car. Today public transport is pushed more to help reduce factors of pollution and congestion which seem to be growing all over the UK. Transportation needs vary greatly depending on peoples commuting needs and therefore trying to focus on transport as a whole over the UK is very difficult to research. I have used over 20 documents to help me research this statement. Literature Review Out of the documents that I was able to find the documents seemed to have very positive or negative opinions about public transport with only a few mixed opinions. The following facts were from mixed view documents. There were many documents which were about crime on public transport and around areas of public transport. The main issues were about train stations and buses where situations of theft were experienced on regular basis. Crime is a factor which is now being dealt with increasingly with investments going into cameras at train stations and increased security. Buses are also being equipped with cameras on board so that drivers can see the upper floor. These articles can be found in the appendix and are articles AP 1, 3, 4 and 5. Many articles were also mixed as they acknowledged improvements being made but were also negative as plans are always based on 5 to10 year developments and cost millions if not billions of pounds. This seems to make people loose faith in public transport as it is slow and costly. An example of this is the  £10bn investment into the London underground found in appendix. Many articles brought forward positive opinions of public transport these opinions and facts are as follows. There are new websites being created to help people plan their journeys by public transport. These sort of sites help people by telling someone which, buses and trains they may need and which ones. A site which I used is www.transportdirect.co.uk. A site like this gives people confidence as they know what forms of transport they may need and how long a journey may take. In appendix this site can be found as AP6. New investments are being made to link major cities. An example is Leeds and Sheffield being linked by one train route. This is designed to help reduce congestion on the M1 this can be seen in appendix AP7. Appendix article AP8 shows achievements made over 2003 and 2004 and tells us of more park and rides schemes being used and set up more.

We Must Stop Global Warming Essay -- Climate Change, 2015

"The most important thing about global warming is this....it's everyone's responsibility to leave this planet in better shape for the future generations than we found it." -- Mike Huckabee Over and over, skeptics, regulation-weary industries, and politically minded scientists have done their best to dispute the fact that the change in global temperature is not a natural occurrence. However, after decades of research and speculations, the advancement of technology has allowed us to prove that, without a doubt, climate change is occurring and that we are the ones responsible for this change. One of the most famous representations depicting anthropogenic contribution to global warming is the Keeling Curve. This curve shows the annual readings of CO2 from Mauna Loa,Hawaii since 1958 (read more at http://scrippsco2.ucsd.edu/history_legacy/early_keeling_curve). Alright, so we are causing climate change†¦now what? Every person on earth is in some way responsible for global warming, but who will be responsible for making it stop? There is no way for us to tackle this issue in an in...

Considering Dysarthria: A Speech Disorder On the Margins :: Biology Essays Research Papers

Considering Dysarthria: A Speech Disorder 'On the Margins' The goal of this paper is to portray dysarthria, a language impairment, as a disorder that is "on the margins" of the category of speech disorders. The argumentation will be that since dysarthria shares common underlying neurological causes with motor diseases rather than with other language impairments, it is set apart from other language impairments and evidence for the overlap of the motor modality with the language modality. Language is arguably one if not the most complex functions produced by the human brain, and one that is all but transparent as to the underlying neurological structures and processes in that so much is going on at the same time that it is hard to tell what is what. What we do know is that there are different areas of representation for different aspects of language. An area in the left hemisphere above the perisylvian fissure in the frontal lobe anterior to the motor cortex roughly controls production and fluency of speech; another area, in the temporal lobe of the same hemisphere roughly controls comprehension and word retrieval. Other regions next to and between these areas carry related functions, and lesioning to them results in variations of the symptoms caused by lesioning one of the central regions described above(1).. These areas are known to us as the "language areas." However, they can be completely intact in a person that is suffering from severe language impairment. Are there other "language areas" then? Strictly speaking, no, loosely speaking, yes. Language is more than a mental function where structures are established, words are retrieved and sound associations are made. The final execution of language is purely a question of complex motor control. Disruption of this complex interaction of motor signals towards the formation of speech is known as dysarthria (2). It is sometimes confused with impairment resulting from injury to the "language areas" (1), illustrating the point that the process of producing language is multi-layered, and that it is often hard to tell what is what. The symptoms of dysarthria may be slurred speech, nasality of sound, or quiet and slow speech (3).. These different impairments reflect the sub-sections in the 'motor symphony' that produces speech: The lips, tongue, teeth and jaw shape specific sounds; the soft palate channels air into either the nasal or oral cavity, producing different sound qualities; the larynx (voice box) makes the air vibrate through the vocal folds to create voice; and finally, the respiratory system powers this process (3).

The Occupation of Japan During 2nd World War

The occupation of Japan was, from start to finish, an American operation. General Douglans MacArthur, sole supreme commander of the Allied Power was in charge. The Americans had insufficient men to make a military government of Japan possible; so t hey decided to act through the existing Japanese gobernment. General Mac Arthur became, except in name, dictator of Japan. He imposed his will on Japan. Demilitarization was speedily carried out, demobilization of the former imperial forces was complet ed by early 1946. Japan was extensively fire bomded during the second world war. The stench of sewer gas, rotting garbage, and the acrid smell of ashes and scorched debris pervaded the air. The Japanese people had to live in the damp, and col d of the concrete buildings, because they were the only ones left. Little remained of the vulnerable wooden frame, tile roof dwelling lived in by most Japanese. When the first signs of winter set in, the occupation forces immediately took over all the s team-heated buildings. The Japanese were out in the cold in the first post war winter fuel was very hard to find, a family was considered lucky if they had a small barely glowing charcoal brazier to huddle around. That next summer in random spots new ho uses were built, each house was standardized at 216 square feet, and required 2400 board feet of material in order to be built. A master plan for a modernistic city had been drafted, but it was cast aside because of the lack of time before the next winter. The thousands of people who lived in railroad stations and public parks needed housing. All the Japanese heard was democracy from the Americans. All they cared about was food. General MacAruther asked the government to send food, when they refus ed he sent another telegram that said, â€Å"Send me food, or send me bullets.† American troops were forbidden to eat local food, as to keep from cutting from cutting into the sparse local supply. No food was was brought in expressly for the Japanese durning the first six months after the American presence there. Herbert Hoover, serving as chairman of a special presidential advisory committee, recommended minimum imports to Japan of 870,000 tons of food to be distributed in different urban areas. Fi sh, the source of so much of the protein in the Japanese diet, were no longer available in adequate quantities because the fishing fleet, particularly the large vessels, had been badly decimated by the war and because the U.S.S.R. closed off the fishing g rounds in the north. The most important aspect of the democratization policy was the adoption of a new constitution and its supporting legislation. When the Japanese government proved too confused or too reluctant to come up with a constitutional reform that satisfied MacArthur, he had his own staff draft a new constitution in February 1946. This, with only minor changes, was then adopted by the Japanese government in the form of an imperial amendment to the 1889 constitution and went into effect on May 3, 1947. The new Constitution was a perfection of the British parliamentary form of government that the Japanese had been moving toward in the 1920s. Supreme political power was assigned to the Diet. Cabinets were made responsible to the Diet by having the prime minister elected by the lower house. The House of Peers was replaced by an elected House of Councillors. The judicial system was made as independent of executive interference as possible, and a newly created supreme court was given the power to review the constitutionality of laws. Local governments were given greatly increased powers. The Emperor was reduced to being a symbol of the unity of the nation. Japanese began to see him in person. He went to hospitals, schools, mines, industrial plants; he broke ground for public buildings and snipped tape at the opening of gates and highways. He was steered here and there, shown things, and kept muttering, â€Å"Ah so, ah so.† People started to call him â€Å"Ah-so-san.† Suddenly the puybli c began to take this shy, ill-at-ease man to their hearts. They saw in him something of their own conqured selves, force to do what was alien to them. In 1948, in a newspaper poll, Emperior Hirohito was voted the most popular man in Japan. Civil li berties were emphasized, women were given full equality with men. Article 13 and 19 in the new Constitution, prohibits discrimination in political, economic, and social relations because of race, creed, sex, social status, or family origen. This is one of the most explicitly progressive statements on human rights anywhere in law. Gerneral Douglas MacArthur emerged as a radical feminist because he was â€Å"convinced that the place of women in Japan must be brought to a level consistent with that of women in the western democracies.† So the Japanese women got their equal rights amendment long before a concerted effort was made to obtain one in America. Compulsory education was extened to nine years, efforts were made to make education more a traning in thinking than in rote memory, and the school system above the six elementary grades was revised to conform to the American pattern. This last mechanical change produced great confusion and dissatisfaction but became so entrenched that it could not be re vised even after the Americans departed. Japan†s agriculture was the quickest of national activities to recover because of land reform. The Australians came up with the best plan. It was basis was this: There were to be no absentee landlards. A person who actually worked the land could own up to 7.5 arcers. Anyone living in a village near by could keep 2.5 acres. Larger plots of land, exceeding these limits, were bought up by the government and sold on easy terms to former tenants. Within two years 2 million tenants became landowners. The American occupation immediately gained not only a large constituency, for the new owners had a vested interest in preserving the change, but also a psychological momentum for other changes they wanted to ini tiate. The American labor policy in Japan had a double goal: to encourage the growth of democratic unions while keeping them free of communists. Union organization was used as a balance to the power of management. To the surprise of the American authorties, this movement took a decidedly more radical turn. In the desperate economic conditions of early postwar Japan, there was little room for successful bargaining over wages, and many labor unions instead made a bid to take over industry and o perate it in their own behalf. Moreover large numbers of workers in Japan were government employees, such as railroad workers and teachers, whose wages were set not by management but by the government. Direct political action therefore seemed more meani ngful to these people than wage bargaining. The Japanese unions called for a general strike on February 1, 1947. MacArthur warned the union leadership that he would not countenace a nationwide strike. The strike leaders yieled to MacArthur†s will. The re after the political appeal of radical labor action appeared to wane. The Americans wanted to disband the great Zaibatsu trust as a means of reducing Japan†s war-making potential. There were about 15 Zaibatsu families such as – Mitsui, Mitsubishi, Yasuda, and Sumitomo. The Zaibatsu controled the industry of Japan. MacArthur†s liaison men pressured the Diet into passing the Deconcentration Law in December 1947. In the eyes of most Japanese this law was designed to cripple Japanese business and i ndustry forever. The first step in breaking up the Zaibatsu was to spread their ownership out among the people and to prevent the old owners from ever again exercising control. The stocks of all the key holding companies were to be sold to the public. Friends of the old Zaibatsu bought the stock. In the long run the Zaibatsu were not exactly destroyed, but a few were weakened and others underwent a considerable shuffle. The initial period of the occupation from 1945 to 1948 was marked by reform, the second phase was one of stabilization. Greater attention was given to improvement of the economy. Japan was a heavy expense to the United States. The ordered breakup of the Zaibatsu was slowed down. The union movement continued to grow, to the ult imate benefit of the worker. Unremitting pressure on employers brought swelling wages, which meant the steady expansion of Japan domestic consumer market. This market was a major reason for Japan†s subsequent economic boom. Another boom to the economy was the Korean War which proved to be a blessing in disguise. Japan became the main staging area for military action in Korea and went on a war boom economy with out having to fight in or pay for a war. The treaty of peace with Japan was signed at San Francisco in September 1951 by Japan, the United States, and forty-seven other nations. The Soviet Union refused to sign it. The treaty went into effect in April 1952, officially terminating the United States military occupation and restoring full independence. What is extraordinary in the Occupation and its aftermath was the insignificance of the unpleasant. For the Japanese, the nobility of American ideals and the essential benignity of the American presence assuaged much of the bitterness and anguish of defeat. For the Americans, the joys of promoting peace and democracy triumphed over the attendant fustrations and grievances. Consequently, the Occupation served to lay down a substantial capital of good will on which both America and Jap an would draw in the years ahead.

Crowd Behaviour Essay

People are likely to act in bizarre ways in a crowd compared to as an individual. A crowd can be defined as a set of individuals who share a common social identification of themselves in terms of that crowd. Crowd members should also share common goals and act in a coherent member (Reicher, 2008). There have been extensive amounts of research into crowd psychology, investigating the apparent causes and reasons for such behaviour to occur. Many different theories exist to attempt to explain why people fall into this interesting state of social influence when they are in crowds. This essay will attempt to investigate how we might best explain crowd behaviour. Le Bon’s (1896) early attempt to explain this phenomenon suggested that crowd behaviours are pathological and abnormal, where people are reduced to a primitive or instinctive mode of behaviour. This theory proposes that feelings of anonymity cause people in a crowd to lose their sense of self and responsibility and act in ways that stem from a ‘group mind’. Through this group mind people are freed from social norms and natural animal instincts are released causing riots and irrational violence. However, since the initial suggestion of the ‘group mind’, this theory has been largely rejected. The main reasoning for this being that the theory does not acknowledge the importance of power in crowd behaviours, which appears to be a key factor in collective behaviour. One speculation that remains important from Le Bon’s group mind theory is that the feeling of crowd anonymity appears to be influential in creating various subsequent theories to explain crowd behaviour, such as the theory of deindividuation. However, the rejection of the group mind does not mean that we should then reject the study of group processes as groups have distinctive properties from individual behaviour. Instead, we should begin to look at group processes with a different perspective. Tajfel (1970) claims that all social behaviour falls on a continuum that spans from interpersonal to intergroup behaviour. Intergroup behaviour is defined with these three criteria: the presence of two distinct groups, low variability in attitudes and behaviour of group members, and low variability in one person’s attitudes to group members.  This helps to explain this readiness in which a person can switch from one view of someone to another (e.g. saying all catholics are bad people, and then going on to say the neighbor (who is a catholic) is such a lovely person). This can arise because when you become part of a group you start to see people as a category not as individuals. The theory of Deindividuation (Deiner, 1976; and Zimbardo, 2007) followed on to these early speculations. The model states that when surrounded by others in a crowd people lose self-awareness. Consequently, people become more susceptible to external cues and to the groups motives and emotions. Ultimately, these factors may lead group members to engage in unsocial and possibly antisocial behaviours. According to Zimbardo, being part of a large group can create a sense of anonymity and diffuses personal responsibility throughout the group for the consequences of one’s actions. This can lead to the loss of identity and a reduced concern for social evaluation. Behaviour resulting can then be impulsive and irrational as there are different set ‘normal’ social and personal norms. Zimbardo’s electric shock experiment gives support to the deindividuation theory, providing evidence that the mean duration of the shock administered by deindividuated participants (they were wearing a coat and a hood to increase anonymity) was nearly twice as long than that of the people who retained their individual identities. Further research also suggests that this sense of anonymity is increased as the size of the group increases and also increases in darker conditions. For example: the violent crowd in the Bristol riots, as darkness fell, violence escalated thus increasing the anonymity of the crowd members. Research by Jaffe and Yinon (1979) compared the mean intensity of shock administered by individuals with that administered by participants in groups of three. As they predicted, those who participated in groups consistently gave much stronger ‘shocks’ than those acting on their own giving evidence for the idea that the sense of anonymity increases with the size of the group. However, some research disagrees that increased anonymity leads to increases antisocial and aggressive behaviour. Some argue that deindividuation and anonymity may in fact result in decreased aggression and improved group relations, indicating that these antisocial behaviours may not be automatic or inevitable consequences of anonymity. Despite much of the early literature proposing that deindividuation factors such as anonymity, loss of self-awareness and group size are associated with antisocial and aggressive behaviours, some more recent findings suggest that deindividuation influences are often sometimes related to increases in pro-social normative behaviour. Zimbardo (1969) provides support for this criticism of the deindividuation theory, having participants either dress in KKK cloaks, or a nurse uniform in an electric shock learning experiment. Results showed that those wearing the nurse uniform chose to reduce the level of shocks administered, and especially in the deindividuated conditions – the person wearing no name tag. In fact, deindividuation by itself did not increase aggression significantly, even for those wearing the KKK outfit. These findings have an influential effect on the understanding of group behaviour as they show that being in a group does not necessarily lead to destructive, antiso cial behaviour as Zimbardo implied. It seems that crowd behaviour often tends to depend on the situation and how salient the norms are. Given the previous literature, Diener (1980) argues that the main factor in crowd behaviour is determined by a loss of self-awareness. He then suggests that factors present in crowd situations such as cohesion and anonymity, can lead people to focus their attention outwards and less on themselves and on personal standards. As a result, people’s behaviour becomes less self-regulated and more determined by immediate cues and norms present in groups around them. Subsequently, these cues will not always direct violence, but will vary across different situations. The literature also fails to consider the context of behaviour or to distinguish anonymity when someone is in a group from anonymity when they are alone. In addition, members of a crowd are barely ever truly anonymous; as individuals identities are often known to other members of the crowd, and they therefore only will appear anonymous to outsiders of the crowd. People often gain a sense of pride rioting together in a group, such as supporters of the same team at a football match, which is far from losing their identities. All of the previous models focus on what is lost when part of a crowd – loss of identity, loss of individuality, and loss of self-awareness. This perspective of understanding group behaviour is a negative and highly  unproductive way to think about collective behaviour; it would be much more productive to think about change (Reicher et al., 1995). Reicher’s research into crowd behaviour has come up with three important features of crowd situations. Firstly, crowds nearly always involve more than one group. This intergroup factor has been essentially ignored in the previous literature for crowd behaviour since the group mind fallacy. Secondly, he suggests that people do not become anonymous, but take on a new identity in a crowd. Reicher (1984) studied vivosection attitudes in Science and Social Science students, with science students generally being more PRO and social sciences students more ANTI. In each category, half of the students were made aware of group membership (e.g. seated together, reffered to as groups, wore KKK membership clothing, etc). Attitudes of Science students became more pro-vivosection and social science students become more anti-vivosection. These findings oppose Deiners theory that deindividuation leads to a loss of self-regulation and gives support to Reicher’s view that you don’t lose your identity in a group based situation, but your identity changes to fall in line with group norms. This follows on from Turners (1983) suggestion of the distinction between personal and social aspects of the self. There is a shift along the interpersonal group continuum from personal identity to social identity. There is then a change in what is seen as the appropriate standard of behaviour. These standards of behaviour and norms are now determined by the group’s social identity rather than by personal or environmental factors. This can help to understand why the behaviour of rioters and police can be so different, when they are exposed to the same stimuli, for when they adopt their respective identities they become influenced by very different goals and social norms. This shows that when a person becomes part of a crowd or group, their social identity as a group member becomes more important and their individual identity becomes less important. Although people may sometimes lose some sense of their identity at times, they will often adopt a stronger sense of their social identity as a member of that particular group. Crowd behaviour, according to Reicher, therefore involves a change rather than a loss of identity. Reicher’s new theory of  crowd behaviour raised four issues that do not fall in line with Deiner’s deindividuation theory. 1. Although crowd behaviour is violent, it is often under control at the same time. 2. Crowds are not always anonymous. 3. Though people are previously suggested to lose self-awareness in crowds and thus respond to cues in particular situations, how come people will respond differently? 4. If crowd behaviour leads to a loss in identity, how come a sense of pride often results from crowd interaction? When Reicher (1987) interviewed people who were part of the St Paul’s riots he received some interesting feedback such as â€Å"we feel great, we feel confident it was a vic tory† and â€Å"You were grinning at everybody, because everyone was from St Paul’s†. These statements provide evidence that those feelings of anonymity and a suggested loss of identity in groups are not present when people are successful in their groups perhaps gaining a sense of pride in their group and coming together to celebrate. To conclude, there are three important points that I would like to reiterate. Firstly, Zimbardo’s pessimism about groups is seemingly unjustified with much evidence pointing in the opposite direction. Depending on each particular situation and the norms that are important in each, behaviour can become either pro-social or anti-social in crowd environments. Though where Zimbardo does seem to be right is that people’s behaviour in a group situation can become much more extreme than how they would behave on their own. The second point is that people’s behaviour in crowds does not always worsen. Support from both Zimbardo and Deiner suggest that in groups people are subjected to a loss of identity and loss of control. However, Reicher’s more recent research into crowd behaviour suggests that this idea is mistaken. It has been shown that people’s behaviour is still in control, yet by different psychological processes. Groups seem to have a common goal in mind in acting as they do, and also that their actions are often motivated by identification with some group. Finally, when viewing group behaviour from an intergroup perspective, the goal and identity directed aspects of collective behaviour are more evident. In almost every situation of crowd behaviour, it is possible to determine an out-group, which will play an important role in the actions of the crowd. Overall, there are many different crowd psychology theories, some of which explain different aspects of crowd behaviour. However, research gives much support to the use of intergroup perspective rather than interpersonal theories to explain this phenomenon. References Diener, E. (1976). Effects of prior destructive behavior, anonymity, an group presence on deindividuation and aggression. Journal of Personality and Social Psychology, 33, 497-507. Diener, E. (1980). Deindividuation, self-awareness, and disinhibition. Journal of Personality and Social Psychology, 37, 1160-1171. Le Bon, G. (1947). The Crowd: a study of the popular mind. London: Ernest Benn. Reicher, S. D., Spears, R. and Postmes, T. (1995). A social identity model of deindividuation phenomena. European Review of Social Psychology, 6, 161-198. Reicher, S. D. (1984b). The St. Pauls’ Riot: An explanation of the limits of crowd action in terms of a social identity model. European Journal of Social Psychology, 14, 1-21. Reicher, S. D. (2008). The Psychology of Crowd Dynamics. Blackwell Handbook of Social Psychology: Group Processess, 9, 151-168 Tafjel, H. (1970). Experiments in intergroup discrimination. Scientijic American, 223, 96102. Turner, J. C. (1983). Some comments on ‘the measurement of social orientations in the minimal group paradigm’. European Journal of Social Psychology, 13, 351-368 Zimbardo, P. G. (1969). The Human Choice: Individuation, reason, and order versus Deindividuation, impulse and chaos. Nebraska Symposium on Motivation, 17, 237-307