Synoptic circulation patterns and its relationship with ground thermal characteristics along an altitudinal transect on sub-Antarctic Marion Island
- Authors: Bierman, Stefni
- Date: 2014
- Language: English
- Type: Thesis , Masters , MSc (Geography)
- Identifier: vital:11516 , http://hdl.handle.net/10353/d1015532
- Description: The climate of Marion Island is driven by synoptic weather patterns which have also been suggested to influence the soil thermal characteristics. The primary aim of this work was to examine the effect of synoptic weather systems on soil temperature dynamics on an altitudinal gradient on the eastern side of Marion Island. The study specifically addresses the implications of climate change on future soil thermal dynamics in a maritime sub-Antarctic environment. Ground temperature were obtained from three ground temperature monitoring stations on the eastern side of Marion Island, which were established along an altitudinal gradient at Long Ridge North (200m a.s.l.), Katedraalkrans (750m a.s.l) and at Delta Extension (1000m a.s.l.). To assess the synoptic weather circulation patterns, a synoptic climate classification methodology that is based on the single station principal component (PCA) and cluster analysis were used. Results show that certain clusters were more dominant than others and over the measured time span certain synoptic weather patterns, mainly cyclonic air circulation types, have decreased while anticyclonic circulation have increased. Soil frost occurs at all three stations on Marion Island, not only under cyclonic circulations (as previously suggested) but significantly under anticyclonic air mass circulation as well. Soil frost is dependent on the duration of post-cyclonic Antarctic air mass circulation. Synoptic weather patterns are also affecting ground surface lapse rates. Changes from positive to negative lapse rates were observed and this predominantly occurred under the atmospheric circulation pattern associated with clusters that are predominantly anticyclonic. Long term climatic change as predicted by the PCA show a reduction in low pressure systems or more anticyclonic conditions affecting the island. These change will significantly affect the soil thermal dynamics at an altitudinal scale on sub-Antarctic Marion Island.
- Full Text:
- Authors: Bierman, Stefni
- Date: 2014
- Language: English
- Type: Thesis , Masters , MSc (Geography)
- Identifier: vital:11516 , http://hdl.handle.net/10353/d1015532
- Description: The climate of Marion Island is driven by synoptic weather patterns which have also been suggested to influence the soil thermal characteristics. The primary aim of this work was to examine the effect of synoptic weather systems on soil temperature dynamics on an altitudinal gradient on the eastern side of Marion Island. The study specifically addresses the implications of climate change on future soil thermal dynamics in a maritime sub-Antarctic environment. Ground temperature were obtained from three ground temperature monitoring stations on the eastern side of Marion Island, which were established along an altitudinal gradient at Long Ridge North (200m a.s.l.), Katedraalkrans (750m a.s.l) and at Delta Extension (1000m a.s.l.). To assess the synoptic weather circulation patterns, a synoptic climate classification methodology that is based on the single station principal component (PCA) and cluster analysis were used. Results show that certain clusters were more dominant than others and over the measured time span certain synoptic weather patterns, mainly cyclonic air circulation types, have decreased while anticyclonic circulation have increased. Soil frost occurs at all three stations on Marion Island, not only under cyclonic circulations (as previously suggested) but significantly under anticyclonic air mass circulation as well. Soil frost is dependent on the duration of post-cyclonic Antarctic air mass circulation. Synoptic weather patterns are also affecting ground surface lapse rates. Changes from positive to negative lapse rates were observed and this predominantly occurred under the atmospheric circulation pattern associated with clusters that are predominantly anticyclonic. Long term climatic change as predicted by the PCA show a reduction in low pressure systems or more anticyclonic conditions affecting the island. These change will significantly affect the soil thermal dynamics at an altitudinal scale on sub-Antarctic Marion Island.
- Full Text:
An assessment of needle ice, snowfall and the zero-curtain effect and its relationship with soil frost dynamics on sub-Antartic Marion Island
- Authors: Zilindile, Mphumzi Brooklyn
- Date: 2013
- Subjects: Snow -- Prince Edward Islands -- Marion Island , Frost -- Prince Edward Islands -- Marion Island , Ice -- Prince Edward Islands -- Marion Island , Marion Island (Prince Edward Islands) -- Description and travel
- Language: English
- Type: Thesis , Masters , MSc (Geography)
- Identifier: vital:11515 , http://hdl.handle.net/10353/d1006908 , Snow -- Prince Edward Islands -- Marion Island , Frost -- Prince Edward Islands -- Marion Island , Ice -- Prince Edward Islands -- Marion Island , Marion Island (Prince Edward Islands) -- Description and travel
- Description: This study aims to uncover the synoptic weather circulation pattern which is associated with the occurrence of needle ice, snowfall and the zero-curtain effect. The method of study was done through an intensive ground climate measurement campaign from April 2008 to May 2009 with a temperature logger installed throughout the recording period. Results from data analyses indicate that the complex changes in climate parameters may lead to an equally complex response in terms of spatial soil frost dynamics and its direct and indirect effects on soil sediment displacement and ecosystem dynamics. Field evidence in the study suggests that on Marion Island needle ice developed in temperatures as high as -0.2 ºC in strong winds. This confirms that the wet environment of Marion Island, which is dominated by diurnal soil frost is fundamentally different from seasonal frost and permafrost environments. The scoria material is susceptible to needle ice growth and the compacted soil alters the micro-climatology of the affected area making it more susceptible to the formation of needle ice. Soil moisture for needle ice formation and growth is provided by the misty conditions associated with the advent of the cold front (pre-cyclonic). Furthermore, observations of needle ice on Marion show that needles are mostly clear with no sediment inclusion. This is indicative of needle ice formation that has not been interrupted by a shortage of moisture. The zero-curtain effect on Marion Island can occur either as a response to the thawing of the soil after the seasonal freeze. The synoptic assessment of snowfall on Marion Island indicates that; snowfall is associated with the passage of a cold front linked to a strong meridional system of low pressure just south of the island.
- Full Text:
- Authors: Zilindile, Mphumzi Brooklyn
- Date: 2013
- Subjects: Snow -- Prince Edward Islands -- Marion Island , Frost -- Prince Edward Islands -- Marion Island , Ice -- Prince Edward Islands -- Marion Island , Marion Island (Prince Edward Islands) -- Description and travel
- Language: English
- Type: Thesis , Masters , MSc (Geography)
- Identifier: vital:11515 , http://hdl.handle.net/10353/d1006908 , Snow -- Prince Edward Islands -- Marion Island , Frost -- Prince Edward Islands -- Marion Island , Ice -- Prince Edward Islands -- Marion Island , Marion Island (Prince Edward Islands) -- Description and travel
- Description: This study aims to uncover the synoptic weather circulation pattern which is associated with the occurrence of needle ice, snowfall and the zero-curtain effect. The method of study was done through an intensive ground climate measurement campaign from April 2008 to May 2009 with a temperature logger installed throughout the recording period. Results from data analyses indicate that the complex changes in climate parameters may lead to an equally complex response in terms of spatial soil frost dynamics and its direct and indirect effects on soil sediment displacement and ecosystem dynamics. Field evidence in the study suggests that on Marion Island needle ice developed in temperatures as high as -0.2 ºC in strong winds. This confirms that the wet environment of Marion Island, which is dominated by diurnal soil frost is fundamentally different from seasonal frost and permafrost environments. The scoria material is susceptible to needle ice growth and the compacted soil alters the micro-climatology of the affected area making it more susceptible to the formation of needle ice. Soil moisture for needle ice formation and growth is provided by the misty conditions associated with the advent of the cold front (pre-cyclonic). Furthermore, observations of needle ice on Marion show that needles are mostly clear with no sediment inclusion. This is indicative of needle ice formation that has not been interrupted by a shortage of moisture. The zero-curtain effect on Marion Island can occur either as a response to the thawing of the soil after the seasonal freeze. The synoptic assessment of snowfall on Marion Island indicates that; snowfall is associated with the passage of a cold front linked to a strong meridional system of low pressure just south of the island.
- Full Text:
Rainfall intensity, kinetic energy and erosivity of individual rainfall events on the island of Mauritius
- Authors: Mongwa, Themba
- Date: 2011
- Subjects: Rain and rainfall -- Mauritius , Soil erosion -- Mauritius , Rainfall intensity duration frequencies -- Mauritius
- Language: English
- Type: Thesis , Masters , MSc (Geography)
- Identifier: vital:11506 , http://hdl.handle.net/10353/452 , Rain and rainfall -- Mauritius , Soil erosion -- Mauritius , Rainfall intensity duration frequencies -- Mauritius
- Description: On most tropical volcanic islands the risk for soil erosion is enhanced due to a complex topography, high intensity rainfall and the exploitation of land for agriculture. Mauritius is a typical maritime tropical volcanic island with a distinct elevated interior. Rainfall is dominated by tropical weather systems and trade winds and the island is under intensive cultivation. Rainfall depth, duration, intensity, kinetic energy and erosivity were analysed for 385 erosive rainfall events at five locations over a five year period (2004 to 2008) on the island of Mauritius. Two stations located on the west coast and three stations sited on the Central Plateau above 550 m a.s.l. are used to provide detailed rainfall data at six minute intervals. Erosive storm events, defined here as a total rainfall exceeding 12.5 mm and a maximum 6-minute intensity exceeding 25 mm/hour, are found to differ markedly between the coastal lowlands and the elevated interior with regards to the frequency, the total rainfall generated, the duration, total kinetic energy and total erosivity of individual events. However, mean kinetic energy, mean and maximum rainfall erosivity (EI30) and maximum intensities (I30) from individual erosive events do not show this distinct differentiation. Erosivity measured during summer exceeds that recorded in winter, but the data indicate that large percentages of winter rainfall on Mauritius are defined as erosive and non-tropical cyclone rainfall can pose a substantial erosion risk. In this maritime tropical environment with its elevated interior, soil erosion risk occurs from storm scale to synoptic scale rainfall events and extreme events generate the bulk of the erosivity. Findings show that using rainfall records at an event scale within soil erosion risk assessments on tropical islands with a complex topography will increase the effectiveness of erosivity estimates
- Full Text:
- Authors: Mongwa, Themba
- Date: 2011
- Subjects: Rain and rainfall -- Mauritius , Soil erosion -- Mauritius , Rainfall intensity duration frequencies -- Mauritius
- Language: English
- Type: Thesis , Masters , MSc (Geography)
- Identifier: vital:11506 , http://hdl.handle.net/10353/452 , Rain and rainfall -- Mauritius , Soil erosion -- Mauritius , Rainfall intensity duration frequencies -- Mauritius
- Description: On most tropical volcanic islands the risk for soil erosion is enhanced due to a complex topography, high intensity rainfall and the exploitation of land for agriculture. Mauritius is a typical maritime tropical volcanic island with a distinct elevated interior. Rainfall is dominated by tropical weather systems and trade winds and the island is under intensive cultivation. Rainfall depth, duration, intensity, kinetic energy and erosivity were analysed for 385 erosive rainfall events at five locations over a five year period (2004 to 2008) on the island of Mauritius. Two stations located on the west coast and three stations sited on the Central Plateau above 550 m a.s.l. are used to provide detailed rainfall data at six minute intervals. Erosive storm events, defined here as a total rainfall exceeding 12.5 mm and a maximum 6-minute intensity exceeding 25 mm/hour, are found to differ markedly between the coastal lowlands and the elevated interior with regards to the frequency, the total rainfall generated, the duration, total kinetic energy and total erosivity of individual events. However, mean kinetic energy, mean and maximum rainfall erosivity (EI30) and maximum intensities (I30) from individual erosive events do not show this distinct differentiation. Erosivity measured during summer exceeds that recorded in winter, but the data indicate that large percentages of winter rainfall on Mauritius are defined as erosive and non-tropical cyclone rainfall can pose a substantial erosion risk. In this maritime tropical environment with its elevated interior, soil erosion risk occurs from storm scale to synoptic scale rainfall events and extreme events generate the bulk of the erosivity. Findings show that using rainfall records at an event scale within soil erosion risk assessments on tropical islands with a complex topography will increase the effectiveness of erosivity estimates
- Full Text:
An analysis of groundwater in Mjinchi District of Central Malawi
- Authors: Mleta, Prince W C
- Date: 2010
- Subjects: Groundwater -- Malawi , Water-supply -- Malawi
- Language: English
- Type: Thesis , Masters , MSc (Geography)
- Identifier: vital:11510 , http://hdl.handle.net/10353/366 , Groundwater -- Malawi , Water-supply -- Malawi
- Description: Groundwater resources is the major source of potable water in Mchinji District of Central Malawi and globally. Although the total amount of water on and under the earth‟s surface is generally assumed to have remained constant, the rapid population boom coupled with extension of agricultural farmland and industrial development are putting pressure and stress on the quality and quantity of water resources. In principal therefore, „use and discard‟ philosophy in water resources cannot be subscribed (Lloyd, 1999). The situation ultimately calls for rational management of water resources to ensure its sustainability. Water intended for human consumption must be free from organisms that are the causative agents of diseases and must not contain chemical substances at concentrations that may be hazardous to human health. In addition drinking water should be aesthetically acceptable, free from unpleasant taste, color, odor and turbidity. Drinking water should also be free from bacteria and viruses whose presence would indicate fecal contamination. Some are known to be toxic and their concentrations must be below acceptable value, taking into account that drinking water is but one of the several pathways by which substances enters the body. ix Due to perceived concerns of over extraction and rapid water resources depletion, optimal management of groundwater resources are now receiving much attention. Their associated literatures have taken quite different approaches both philosophically and operationally to the analysis of how groundwater should be managed, allocated and cared for spatially and temporally. This study investigated the spatial and temporal fluctuations of concentrations of chemical and biological substances in groundwater such as pH, electrical conductivity, total dissolved solids, iron, fluoride, manganese, chloride, sulfates, sodium and fecal coliform in Mchinji District of Central Malawi. Through examination and analysis of static water levels as an indicator of water table fluctuations, groundwater availability was also measured. It was found that anthropogenic activities on the landscape can impact the quality and quantity of the water resources in this area and this impact on the various sectors of the inhabitant‟s livelihoods. Groundwater in Mchinji is composed of a number of chemical and biological elements whose origin is either from the material in which it percolates through, or stored before exploitation. Anthropogenic activities in this area plays a role in the quality and quantity of groundwater through land use and land cover change as evidenced by comparisons of Landsat Thematic x Mapper™ satellite images over different time scales. In Mchinji no regular groundwater monitoring is being done indicating a deficiency in sustainability interventions of the resource. This study calls for integrated and sustainable water resources management and coordinated efforts amongst water users, local councils, regulatory authorities and environmental policy makers. Of far greater importance in groundwater sustainability analysis is the issue of groundwater monitoring. It is imperative therefore to preserve the resource while preservation is still possible. Groundwater is now turning into „blue gold‟ and becoming a highly sought-after commodity. It should, however, be utilized sustainably to meet the needs of the present without compromising the ability of future generations to meet their own needs.
- Full Text:
- Authors: Mleta, Prince W C
- Date: 2010
- Subjects: Groundwater -- Malawi , Water-supply -- Malawi
- Language: English
- Type: Thesis , Masters , MSc (Geography)
- Identifier: vital:11510 , http://hdl.handle.net/10353/366 , Groundwater -- Malawi , Water-supply -- Malawi
- Description: Groundwater resources is the major source of potable water in Mchinji District of Central Malawi and globally. Although the total amount of water on and under the earth‟s surface is generally assumed to have remained constant, the rapid population boom coupled with extension of agricultural farmland and industrial development are putting pressure and stress on the quality and quantity of water resources. In principal therefore, „use and discard‟ philosophy in water resources cannot be subscribed (Lloyd, 1999). The situation ultimately calls for rational management of water resources to ensure its sustainability. Water intended for human consumption must be free from organisms that are the causative agents of diseases and must not contain chemical substances at concentrations that may be hazardous to human health. In addition drinking water should be aesthetically acceptable, free from unpleasant taste, color, odor and turbidity. Drinking water should also be free from bacteria and viruses whose presence would indicate fecal contamination. Some are known to be toxic and their concentrations must be below acceptable value, taking into account that drinking water is but one of the several pathways by which substances enters the body. ix Due to perceived concerns of over extraction and rapid water resources depletion, optimal management of groundwater resources are now receiving much attention. Their associated literatures have taken quite different approaches both philosophically and operationally to the analysis of how groundwater should be managed, allocated and cared for spatially and temporally. This study investigated the spatial and temporal fluctuations of concentrations of chemical and biological substances in groundwater such as pH, electrical conductivity, total dissolved solids, iron, fluoride, manganese, chloride, sulfates, sodium and fecal coliform in Mchinji District of Central Malawi. Through examination and analysis of static water levels as an indicator of water table fluctuations, groundwater availability was also measured. It was found that anthropogenic activities on the landscape can impact the quality and quantity of the water resources in this area and this impact on the various sectors of the inhabitant‟s livelihoods. Groundwater in Mchinji is composed of a number of chemical and biological elements whose origin is either from the material in which it percolates through, or stored before exploitation. Anthropogenic activities in this area plays a role in the quality and quantity of groundwater through land use and land cover change as evidenced by comparisons of Landsat Thematic x Mapper™ satellite images over different time scales. In Mchinji no regular groundwater monitoring is being done indicating a deficiency in sustainability interventions of the resource. This study calls for integrated and sustainable water resources management and coordinated efforts amongst water users, local councils, regulatory authorities and environmental policy makers. Of far greater importance in groundwater sustainability analysis is the issue of groundwater monitoring. It is imperative therefore to preserve the resource while preservation is still possible. Groundwater is now turning into „blue gold‟ and becoming a highly sought-after commodity. It should, however, be utilized sustainably to meet the needs of the present without compromising the ability of future generations to meet their own needs.
- Full Text:
- «
- ‹
- 1
- ›
- »