Climate Anomalies in the World - Research Proposal Example

Climate Anomalies in the World Abstract The major governing factor for climatic changes in the world is attributable to the hemispheric flow. This flow has a definite link in controlling the extent of precipitation and temperature variations in the region. The hemispheric flow had been responsible for the occurrence of extreme weather, like, cold dry winter of 1963 and the dry hot summer of 1976 in Untied Kingdom, substantiating the above fact. Introduction Planetary waves are large-scale motions due to variation of horizontal Coriolis force on the b-plane in a barotropic, non-divergent and statically stable atmosphere (Rossby, 1939). The wave mechanics revealed by Rossby relied on the vorticity conservation which guided the studies on the theoretical meteorology until today (Hirota, 1994). The waves are disturbed by two forcing, namely, Orographic forcing and Thermal forcing. Orographic forcing, more relevant in northern hemisphere owing to dominating surface topography with Rocky Mountain and Tibetan plateau, relates to planetary waves generated due to the compression and expansion of air columns, leading to vortex stretching which can be balanced by the vorticity advection (Dickinson, 1978). Thermal forcing, varying with seasonal change in thermal effect, relates to generation of planetary waves by the adiabatic heating and cooling due to rising and sinking air motions; this maybe balanced by temperature advection (Ashe, 1987). In the subsequent paragraphs we shall examine climate anomalies for a particular region in the context of the large scale hemispheric wave pattern with a multiple objective to firstly, convert temperature and precipitation data, obtained from the Plymouth University Portal, into appropriate graphs, secondly, discuss and compare the seasons with reference to the hemispheric flow and lastly, discuss the possible reason for the variation in the temperature and precipitation on temporal and spatial scales. Methodology Examination of the climate anomalies involved collection of temperature and precipitation data from four regions which was picked from Plymouth University Portal module EOE3304. The data was recorded in Microsoft excel 2007 for further conversion into suitable graphs. This was followed by statistical analysis of the data which included determination of mean temperature and standard deviation for the four regions. The monthly hemispheric charts were plotted with the help of NOAA’s Climate Diagnostics Centre following the link, http://www.cdc.noaa.gov/cdc/dtat.ncep.reanalysis.derived.html. Following steps are required for obtaining the plot:- When the above link opens Click on ‘Pressure level Data’. The page automatically moves down. Now click on the ‘Geo-potential height’. This should open a new page, scroll down and Click on ‘make plot (Monthly Mean)’. To improve the chart quality, adhere to following details:- Select latitude between 20 and 90N, Select 500 mb and Select suitable dates (from, to). Now, select ‘Plot’ on white background, Polar stereographic and Remove Colour Plot. Finally click on Create Plot. Figure 1: Map of Europe, Source: Praxis network, 2007 The results were obtained place-wise, for four different regions, for summer and winter seasons. All graphs show the average monthly temperature or precipitation during a season. The data has been taken from the following regions (also marked in Figure 1 above):- Station Elevation (m) Latitude Longitude Toulouse 152 43.60 N 1.40 E Edinburgh 41 55.95 N 3.35 W Alborg 13 57.10 N 9.87 E Helsinki 53 60.30 N 25.00 E Table 1: Region Coordinates Final Results Figure 2: shows the average summer temperature for the period 1951-1991 for all stations Toulouse The average summer temperature graph shows the average maximum temperatures recorded in Toulouse from 1951 to 1991. The highest average temperature of 21.9 °C was recorded in Toulouse in the summer of 1990 while lowest temperature is depicted, in the graph, in the summer of 1989; however, this lowest temperature be neglected due to an error in the given data for the summer of 1989. The average summer temperature, about the complete period, is close to the mean level (20 °C) with a variation of few degrees up or down with an exception of the summer of 1989 where mercury drops down to 7°C. Helsinki The average summer temperature, about the complete period, is close to the mean level (15 °C) with a variation of few degrees up or down with an exception of the summer of 1989 where mercury drops down to 11°C. One interesting observation from the graph is that the temperatures continuously remained above the mean from 1965 to 1975. Edinburgh Edinburgh shows minimum average summer temperature with only slight variation from the mean temperature of 14°C, throughout the period of observation. Alborg Alborg shows a similar average summer temperature profile to Edinburgh with mean temperature being 14°C and very less variations (by one or two °C) throughout the period of observation. Figure 3: shows the average winter temperature for the period 1951-1991 for all stations Toulouse The average winter temperature graph shows the average maximum temperatures recorded in Toulouse with the mean temperature of 5°C. The temperature varies from 4°C to 8 °C between 1951 and 1971 and from 5°C to 8 °C between 1971 and 1989. In 1991, the mercury hits the all time low temperature of 3°C. Helsinki Helsinki recorded the lowest temperature of -13 °C in the winter of 1985 with the mean temperature of -6°C for the complete period. Steep variations of temperatures are observed between 1951 and 1965 (-2 to -7 °C), 1965 and 1983 (-1 to -11 °C), and with steepest and maximum variations between 1984 and 1991 (-1 to -13 °C). Edinburgh Edinburgh shows the mean temperature of 4°C with only slight variation throughout the period of observation. The temperature varies from 2°C to 6 °C between 1951 and 1987. The temperature crosses the 5°C mark only on few occasions. Alborg Alborg shows the mean temperature of 0°C with significant variations throughout the period. The temperature varies from 1°C to -4 °C between 1951 and 1965, -3°C to 3 °C between 1966 and 1977, -3°C to 4 °C between 1978 and 1991 with the minimum recorded temperature of -4 °C in 1963. Figure 4: shows the average summer precipitation for the period 1951-1991 for all stations except Alborg station which started from 1961 to 1991 Toulouse Mean precipitation in Toulouse was recorded as 50mm. The maximum and minimum precipitation was observed as 120mm in 1977 and 20mm in 1953, respectively. The variation of +25mm, about the mean, is seen in the precipitation, throughout the observation period with exceptions of +50mm, +40mm and +70mm during 1957, 1963 and 1977, respectively. Helsinki Mean precipitation in Helsinki was recorded as 125mm. The maximum and minimum precipitation was observed as 200mm in 1977 and 70mm in 1965, respectively. Precipitation remained above mean from 1953 to 1963 and then gradually dropped till 1973. The maximum variations are observed between 1973 and 1977 where precipitation reaches its max value. The amounts were around the mean for rest of the period. Edinburgh Mean precipitation in Edinburgh was recorded as 170mm. The maximum and minimum precipitation was observed as 275mm in 1957 and 1977 and 105mm in 1955, respectively. Steep variations in precipitation were observed in this region. Starting with 200mm in 1951, precipitation fell to 100mm in 1955 and then climbed to 275mm in 1957. The amounts were around the mean for rest of the period with an exception of 1977 when precipitation soared to maximum for the second time in the period of observation. Alborg This region received maximum precipitation in comparison to the other regions. Mean precipitation in Alborg was recorded as 220mm. Starting with 300mm in 1951, precipitation fell to 100mm in 1955 and then climbed to 340mm in 1957. The amount of precipitation continued to fluctuate about the mean for rest of the period with an exceptional decrease in 1965 with value of 110 mm and a sharp increase with a value of 350mm in 1977. Combined Observation The amount of the precipitation decreased in all the locations in 1955, 1959, 1965, 1973 and 1979, while, it increased for all the regions in 1957, 1963,1971, 1975, 1977, 1981 and 1989. In addition, all the locations ended up with precipitation values less than the values at the beginning of the period. Figure 5: shows the average winter precipitation for the period 1951-1991 for all stations except Alborg station which started from 1961 to 1991 Toulouse Mean precipitation in Toulouse was recorded as 50mm. A continuous fluctuation of amount of precipitation is observed about the mean. The precipitation goes beyond 75mm mark for about six times in the observed period while it does not fall below 25mm mark for the complete duration with exception of 1953 (20mm) and 1991 (5mm). Helsinki Mean precipitation in Helsinki was recorded as 100mm. The maximum and minimum precipitation was observed as 160mm in 1955 and 50mm in 1953 and 1987, respectively. A continuous fluctuation of amount of precipitation is observed about the mean. The amount of precipitation starts with 130mm in 1951, increased to 150mm in 1952, decreased in 1953 to 50mm then rose to 150mm in 1955. The amount of precipitation kept rising and falling until 1991, thereafter. Edinburgh Mean precipitation in Edinburgh was recorded as 170mm. Precipitation started with value of 180mm in 1951, decreased sharply in 1953 to 90mm and rose again in 1955 to reach 220mm. There was an increase in precipitation in 1965 which gradually subsided by 1977, followed by fluctuation about the mean till 1986 and a sudden drop to 100mm in 1987. Precipitation rose to 210mm in 1989 and ended up with 125mm in 1991. Alborg Precipitation started with value of 220mm in 1951, decreased sharply in 1953 to 100mm and rose again in 1955 to reach 275mm before it dropped to 180mm in 1957 and to 150mm in 1963. There was an increase in precipitation in 1966 to a level of 240mm followed by 220mm in 1975, which gradually subsided by 1976 to 140mm, followed by 240mm in 1977. There was steep decrease in precipitation in 1988 to 140mm and finally ended up with 160mm in 1991. Combined Observation The amount of the precipitation decreased in all the locations in 1953, 1957, 1965, 1977 and 1987, while, it increased for all the regions in 1955, 1959,1975, 1979, 1984, 1990 and 1991. In addition, all the locations ended up with precipitation values less than the values at the beginning of the period. Statistics Tables Toulouse Edinburgh Alborg Helsinki Temp PPT Temp PPT Temp PPT Temp PPT Winter 1962/62 2.6 46.4 0.9 36.9 -4.3 11.3 -9.2 36.1 Winter 1982/83 5.4 60 3.6 54.3 1.5 47.3 -3.2 54.7 Summer 1976 21.8 43.7 15.6 26.9 15.7 22.7 14.5 44.5 Summer 1983 21.5 75.7 14.9 37.4 15.6 20.7 15.8 44.3 Table 2: shows the average winter and summer data for specific years Temperature Toulouse Edinburgh Alborg Helsinki winter summer winter summer winter summer winter summer Mean 5.6 19.6 3.6 14.0 -0.3 14.7 -5.8 15.3 Stdev 0.99 2.447 1.116 0.7 2.141 0.9 1.2 2.92 Table 3: shows the average temperature and standard deviation for all stations in the period between 1961-1991 Precipitation Toulouse Edinburgh Alborg Helsinki winter summer winter summer winter summer winter summer Mean 54.1 49.6 51 60 39.63 58.8 43.4 65.0 Stdev 19.56 22.2 16 22 13.35 23.0 16.53 19.6 Table 4: shows the average precipitation and standard deviation for all stations in the period between 1961-1991 winter 1962-63 Precipitation Winter 1962-63 Temperature mean Stdev mean Stdev Toulouse 46.4 24.2 Toulouse 2.3 0.6 Edinburgh 36.9 19.9 Edinburgh 0.9 1.7 Alborg 11.3 8.1 Alborg -4.3 3 Helsinki 36.1 23.2 Helsinki -9.1 2.1 Winter 1982-83 Precipitation Winter 1982-83 Temperature mean Stdev mean Stdev Toulouse 60 37.2 Toulouse 5.4 0.8 Edinburgh 54.3 27.5 Edinburgh 3.6 1.8 Alborg 47.3 22.2 Alborg 1.5 2.3 Helsinki 54.7 36.3 Helsinki -3.2 3.4 Table 5: shows the mean and standard deviation for temperature and precipitation values for all the stations in winters 1963 and 1983 summer 1976 Temperature Summer 1976 Precipitation Mean Stdev Mean Stdev Toulouse 21.8 0.8 Toulouse 43.7 38.6 Edinburgh 15.6 0.7 Edinburgh 26.9 8 Alborg 15.7 1.7 Alborg 22.7 8.7 Helsinki 14.5 1.6 Helsinki 44.5 5 summer 1983 Temperature Summer 1983 Precipitation Mean Stdev Mean Stdev Toulouse 21.5 2.7 Toulouse 75.7 65.4 Edinburgh 14.9 2.2 Edinburgh 37.4 27.1 Alborg 15.6 1.5 Alborg 20.7 5.9 Helsinki 15.8 2.1 Helsinki 44.3 19.1 Table 6: shows the mean and standard deviation for temperature and precipitation values for all the stations in summers 1976 and 1983 Hemispheric Flow: Winter 1963 and 1983 Figure 6: Winter 1963 Hemispheric flow, NOAA, 2007. The hemispheric chart shows three waves. A high pressure ridge dominates Eastern Europe, Western Europe region is mainly dominated by low pressure and the flow is northwesterly over the Himalayas and Rockies, associated with prominent downstream troughs that lie on the on the pole ward sides of the mean jet streams. UK and the western part of France are affected by high pressure ridge, while Scandinavia is affected by a depression, as depicted by the close contours in the chart. Figure 7: Winter 1983 hemispheric flow, NOAA, 2007. The hemispheric chart shows four waves (approximately). A high pressure ridge dominates entire Europe, UK and Scandinavia are affected by low pressure, contours being closely placed, and the flow is northwesterly over the Himalayas and Rockies, associated with prominent downstream troughs that lie on the on the pole ward sides of the mean jet streams. Summer 1976 and 1983 Figure 8: Summer 1976 Hemispheric flow, NOAA, 2007. The hemispheric chart shows six waves (approximately). A high pressure ridge dominates Western Europe, Eastern Europe is affected by low pressure trough, and UK, France and Scandinavia are affected mainly by the high pressure ridge and presence of high pressure ridges over the Rockies, the Atlas Mountains of northwest Africa, the Albs and Caucasus, with prominent short wave troughs to the west of each range. Figure 9: Summer 1983 Hemispheric flow, NOAA, 2007. The hemispheric chart shows six waves (approximately). A high pressure ridge dominates Western Europe, to the south of UK and Eastern Europe is affected by high pressure ridge. However, northern parts of UK and Scandinavia show closely placed contours, indicating a low pressure system flow. There is a presence of high pressure ridges over the Rockies, the Atlas Mountains of northwest Africa, the Albs and Caucasus, with prominent short wave troughs to the west of each range. Analysis: Winter 1963 The hemispheric chart shows three waves. A high pressure ridge dominated Eastern Europe and Western Europe region was mainly dominated by a low pressure system. Alborg and Edinburgh The two stations were affected mainly by the high pressure ridge (Fig 6). The light northerly wind brought an extremely cold and dry air, as is evident from temperature and precipitation graphs (Figure 3 and 5). The standard deviation (Table 5) with regard to these stations indicates extreme winter in 1963. Toulouse Toulouse was affected by high pressure ridge on the western part and low pressure trough on the eastern part of the region. North Westerly wind affected the region by bringing cold and moist air from over the Atlantic resulting in extreme temperature values during 1963 (Figure 3). The standard deviation (Table 5) with regard to Toulouse indicates extreme winter in 1963. The region was not dry in Toulouse due to the moist air and the presence of a low pressure trough over the region which brought rain to Toulouse, and as a result Toulouse recorded maximum precipitation of 46.4mm, among the regions considered. Helsinki Helsinki was mainly affected by a low pressure trough which brought high average rainfall in the region. Here, winter was not as extreme as the other regions, with the standard deviation of 2.1°C in temperature. Summary: Winter 1963 The orographic forcing determines the positions of major ridges and troughs in the northern hemisphere and winter time stationary waves at the jet stream level, while thermal forcing makes an important input to maintain the surface lows over the high latitude oceans. Analysis: Winter 1983 Winter 1983 was associated with four waves (Figure 7). The hemispheric flow over Europe was normal, without any extreme conditions, due to the absence of high pressure ridges and low pressure troughs. Four waves flow, being weaker than a three wave flow does not result in extreme conditions, as is the situation with a three waves flow. Analysis: Summer 1976 Summer 1976 was associated with, approximately, six waves (Figure 8). A high pressure ridge dominated Western Europe and Eastern Europe was affected by low pressure trough (Figure 8). The summertime flows are more energetic and can generate potential energy by adiabatic heating gradients associated with thermal contrasts between the warm landmasses and the cooler oceans. A large pressure gradient force causes the isobars to be close together in summer as compared to winter. Thus, the winds are likely to be faster in summers. Alborg and Edinburgh A high pressure ridge dominated the two stations. The northwesterly winds, responsible for bringing cold wind, were light. This resulted in extremely hot and dry weather, as is evident from temperature and precipitation graphs (Figure 2 and 4). Table 6 indicates that the standard deviation level, during the 1976 summer, were extreme and the two stations experienced drier weather in comparison. Toulouse The hemispheric flow over Europe was normal, without any extreme conditions, due to the absence of high pressure ridges and low pressure troughs. The summer was a normal in Toulouse as can be seen from the graph (Figure 8). Helsinki Helsinki was mainly affected by a low pressure trough which brought high average rainfall in the region. Here, summer was not as extreme as the other regions, with the standard deviation of 1.6°C in temperature (Figure 8 and table 6). Summary: Summer 1976 Alborg and Edinburgh experienced drier weather, in comparison, as high pressure ridge dominated the two stations. Toulouse saw normal summer due to normal hemispheric flow over Europe. Helsinki witnessed heavy rainfall, being affected by a low pressure trough. Analysis: Summer 1983 A high pressure ridge dominated Western Europe, to the south of UK and Eastern Europe region. However, the northern part of UK and Scandinavia were affected by a low pressure system flow as indicated by the closely placed contours. Alborg A high pressure ridge dominated Alborg station. The south westerly winds were light causing warmer conditions. This resulted in extremely hot and dry weather, as is evident from temperature and precipitation graphs (Figure 2 and 4). Table 6 indicates that the standard deviation level, during the 1983 summer, were extreme and the two stations experienced drier weather in comparison. Edinburgh The station is located between a westerly flow and a high pressure ridge as shown in graph (Figure 9). The light south westerly winds brought warm and moist weather. This resulted in extremely hot and dry weather, as is evident from temperature and precipitation graphs (Figure 2 and 4). Table 6 indicates that the standard deviation level, during the 1983 summer, were below mean values and moist South Westerly winds kept an even precipitation over the region. Toulouse The station was dominated by a high pressure ridge as shown in the graph (Figure 9). The light south westerly winds brought warm and moist weather. This was the reason for high temperature and precipitation levels in the region as compared to the other stations. Helsinki Helsinki was mainly affected by a low pressure trough which brought high average rainfall in the region. Here, summer was not as extreme as the other regions (Figure 8). The region recorded maximum precipitation among the four stations as shown by mean and standard deviation (Table 6). Summary: Summer 1983 A high pressure ridge dominated Alborg station which brought an extremely hot and dry weather in terms of temperature and precipitation. The light south westerly winds brought warm and moist weather to Toulouse and Edinburgh. Helsinki recorded maximum precipitation among the four stations owing to a low pressure trough. Correlations Figure 10: A negative correlation between precipitation and temperature in Edinburgh in the period 1951-1991 with R2= 0.43 Figure 11: A negative correlation between precipitation and temperature in Helsinki in the period 1951-1991 with R2= 0.04 Figure 12: Winter 1983 hemispheric flow at 200mb, NOAA, 2007. Figure 13: Winter 1983 hemispheric flow at 500mb, NOAA, 2007. Figure 14: Winter 1983 hemispheric flow at 1000mb, NOAA, 2007. Hemispheric Flow with Height Hemispheric flow and height have an inverse proportionality relation; if height increases hemispheric flow decreases and vice versa. Hemispheric flow is strongest at 500mb, contours being close together making the flow stronger and quite weak at 1000mb, as the contours are placed apart. The wave amplitudes in the geo-potential height increase with the height up the tropopause level which indicates a correspondent barotropic component in the vertical structures, for example, there is no phase tilt with changing height. Between 200mb to 500mb, though the flow is considered strong, but is significantly hampered by orographic features such as the Rockies and the Himalayas. These features deflect the flow, as can be seen from the meander of the flow over these regions, reducing the vorticity between the mountain and the tropopause. At 500mb, the contour interval changes, steep pressure gradient force as the isobars appears to be closer to one another. In addition, the flow at 500mb tends to be faster as a result of the reduced friction with the surface, resulting in faster wind. The fastest winds can be found where warm and cold air meets. The mountains play an important part in determining the longitudes major weather patterns in the wintertime northern hemisphere at 500mb. The increased flow speed and meander at 1000mb tends to cut off the flow into smaller vortexes which are same as the ocean eddies. The 1000mb is associated with high pressure systems over land mass’s and low pressure systems over the oceans. Conclusion The climate in Europe has shown to be more influenced by the hemispheric flow than the ocean. The results and analysis have shown that dominance of high pressure ridges result in extreme climate in winter as well as summer; winters are rendered cold and dry while summers become hot and dry. Effect of lo pressure troughs normalizes the temperature and precipitation in the regions. The relationship between temperature and precipitation has been found to be significant; more the precipitation in summer, lower the temperature and more the precipitation in winter, higher the temperature. It has been noticed that presence of three waves tend to result in extreme climate while under four waves presence, conditions are normal. Read More