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How climate change impacts the habitat building vegetation in the Baltic Sea : How are the species bladderwrack & common eelgrass impacted by climate change in the Baltic Sea?Axelsson, Sophia January 2022 (has links)
The world's seas are without a doubt being changed by global warming, affecting all species, causing ecosystem changes. The overall low biodiversity in the Baltic Sea leads to sensitive unique qualities. Understanding how climate change in the Baltic Sea will affect key species is important to understanding how the Baltic Sea coastal environment will look in the future. Fucus vesiculosus, and Zostera marina, are key habitat building vegetation in the Baltic Sea, building up most of the canopies by the coasts on rocky and sandy bottoms. How are these species affected by climate change in the Baltic Sea? The result showed that both Fucus and Zostera growth is stimulated during most of the year with rising temperatures, but during summer heatwaves inhibit the plants, raising the mortality. Fucus will migrate more south, as the Baltic Sea will likely become fresher, and Zostera will continue to thrive if nutrients are reduced. Both species will experience die-offs during summer heatwaves. / Världens hav förändras utan tvekan av den globala uppvärmningen, vilket påverkar alla arter och leder till ekosystem förändringar. Den övergripande låga biologiska mångfalden i Östersjön leder till känsliga unika förhållanden. Att förstå hur klimatförändringarna i Östersjön kommer att påverka nyckelarter är viktigt för att förstå hur Östersjöns kustmiljö kommer att se ut i framtiden. Fucus vesiculosus och Zostera marina, är viktiga habitatsbildande växter i Östersjön, som bygger upp majoriteten av ekosystemen vid kusterna på steniga och sandiga bottnar. Hur påverkas dessa arter av klimatförändringar i Östersjön? Resultatet visade att tillväxten av både Fucus och Zostera stimuleras under större delen av året med stigande temperaturer, men under sommaren hämmar värmeböljor växterna, vilket ökar dödligheten. Huvudslutsatserna är att Fucus kommer att vandra mer söderut, eftersom Östersjön med största sannolikhet kommer att bli sötare från norr, och Zostera kommer fortsätta trivas om näringsmängden minskar. Båda arterna kommer drabbas av dödsfall under värmeböljor på sommaren.
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Understanding Middle Atmospheric Composition Variability from the Solar Occultation for Ice Experiment Instrument and Other DatasetsDas, Saswati 28 October 2022 (has links)
This dissertation comprises multiple studies surrounding the middle atmosphere's chemistry, composition, and dynamics. The middle atmosphere refers to the region from ~ 10 km to ~ 100 km and consists of the Stratosphere, Mesosphere, and Lower Thermosphere. The Stratosphere, Mesosphere, and Thermosphere are bounded by pauses where the strongest changes in chemical composition, movement, density, and thermal behavior take place. While several studies in the past have investigated the chemical composition of the middle atmosphere and quantified the distribution of various species from the stratosphere to the lower thermosphere, seasonal variations and redistribution of species resulting from transport events make it important to continuously monitor the middle atmosphere. Dynamic events such as Sudden Stratospheric Warmings (SSW) impact the temperature gradient and the zonal mean wind pattern in the stratopause. Descent events triggered by SSWs result in enhanced transport of species from the lower thermosphere to the stratosphere. Temperature increments during SSWs have an important impact on Polar Stratospheric Clouds (PSCs), resulting in Antarctic ozone enhancement and a smaller ozone hole. The middle atmosphere is, thus, home to a diverse range of dynamics and chemistry, making it a critical subject that warrants attention from the science community. The continuous monitoring of the middle atmosphere is important to this end. Several satellite missions in the past have been dedicated to monitoring the middle atmosphere and collecting data for decades. However, continual revisions and revaluations of measurement approaches and the introduction of novel space instruments are necessary to compensate for the limitations associated with existing missions, expand the extant specimen database, and improve phenomenon-centric observations.
The Solar Occultation for Ice Experiment (SOFIE) is one of the two instruments on the Aeronomy of Ice in the Mesosphere (AIM) spacecraft. The studies presented in this dissertation primarily focus on the use of SOFIE observations combined with results from other science missions, an atmospheric model, and other datasets.
Chapter I is an overview of the research goals and the motivations that propelled this research. In Chapter II, a validation study of the Version 1.3 SOFIE ozone data against the Atmospheric Chemistry Experiment (ACE) and the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) ozone data is presented. The SOFIE-ACE and SOFIE-MIPAS data pairs demonstrate similar variability in the ozone vertical profile. SOFIE vertical ozone profiles agree best with ACE from 30 - 70 km and MIPAS from 30-64 km. The mean difference values averaged over all seasons and both hemispheres are typically < 24% with ACE and < 20 % with MIPAS.
Atomic oxygen is an important species in the mesopause region (~ 80 – 100 km) that impacts the region's ozone photochemistry and radiative balance. In Chapter III, SOFIE ozone measurements used to derive daytime atomic oxygen are compared to coincident retrievals from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument and the Naval Research Laboratory Mass Spectrometer Incoherent Scatter radar (NRLMSIS 2.0) model. The datasets agree qualitatively. Results indicate a strong seasonal variation of atomic oxygen with summer and wintertime maxima at ~ 84 km and 94 km, respectively.
The middle atmospheric composition is redistributed by the transport of species during SSWs. In Chapter IV, the 2019 SSW in the northern hemisphere that triggered a large transport event from the lower thermosphere to the stratosphere is evaluated using SOFIE, ACE, and the Modern-Era Retrospective analysis for Research and Applications (MERRA-2) observations. The event was similar to the major SSW-triggered descent events in the northern hemisphere since 2004 and led to the enhancement of nitric oxide produced by Energetic Particle Precipitation, attributed to unusual meteorology. The transport peak descended by ~ 5-6 km every 10 days.
An SSW event occurred in the southern hemisphere in 2019 and led to enhanced ozone in the stratosphere. In Chapter V, satellite instruments, ground station data, and measurements from NASA Ozone Watch are used to conclude that large temperature increments evaporated PSCs, resulting in the lower conversion of halogen reservoir species into ozone-destroying forms. Thus, a large ozone enhancement was recorded in 2019.
Chapter VI concludes all findings and Chapter VII summarizes future work. / Doctor of Philosophy / The middle atmosphere is the region between ~ 10 and 100 km in the atmosphere and is comprised of the Stratosphere, Mesosphere, and Lower Thermosphere. The middle atmosphere is a dynamic region, and the chemistry of this region is subject to variations occurring naturally or those triggered by anomalous events such as Sudden Stratospheric Warmings (SSW). Several species in the middle atmosphere need to be measured continuously or reevaluated for improved understanding. Dynamical events in the middle atmosphere are responsible for transporting and redistributing species in the middle atmosphere. Thus, the continuous monitoring of the middle atmosphere is necessary. Novel approaches with improved techniques and approaches are thus important to explore the middle atmosphere and quantify the chemistry of the region.
The Solar Occultation for Ice Experiment (SOFIE) instrument is an instrument onboard the Aeronomy of Ice in the Mesosphere (AIM) spacecraft. SOFIE typically measures at high latitudes and looks at a wide range of wavelengths. This dissertation uses SOFIE and other datasets to evaluate the varying chemistry and dynamics of the middle atmosphere. The dissertation addresses four research problems and assimilates them to evaluate the middle atmosphere.
Ozone is an important species in the middle atmosphere, which is present in the highest quantity in the stratosphere, followed by the lower thermosphere (~ 85 – 100 km). Ozone is important as it absorbs ultraviolet radiations and impacts the stratospheric radiative balance. Missions in the past have monitored ozone in the middle atmosphere. Novel approaches and improved observation techniques to compensate for the limitations of past missions and the continuous measurement of ozone are necessary. Thus, ozone retrievals from SOFIE are validated against independent and established datasets to demonstrate the robustness and usability of the SOFIE ozone data product within the atmospheric science community.
Atomic oxygen is an important species in the mesopause region (~ 80 – 100 km) because of its role in ozone photochemistry and impact on the radiative balance of the region. It is technologically challenging to make direct measurements of atomic oxygen; thus, most conventionally, derived measurements and model results are used. To this date, atomic oxygen has been understood in a limited capacity with several inaccuracies. To improve the understanding of atomic oxygen and fill the current knowledge gaps, atomic oxygen is derived from SOFIE ozone measurements during the daytime using the Chapman equations for ozone photochemistry. Further, the derived atomic oxygen is compared to other established datasets from satellite instrument-derived measurements and model predictions. The seasonal variability of atomic oxygen is evaluated with a focus on the difference in its behavior during summer and winter. Lastly, inter-hemispheric differences in atomic oxygen distribution are evaluated.
Apart from the natural atmospheric variation in species, SSW-triggered transport events redistribute species in the atmosphere. The 2019 SSW event in the northern hemisphere was similar to those in 2004, 2006, 2009, and 2013. Large quantities of nitric oxide were transported from the lower thermosphere to the stratosphere. Air poor in water vapor and methane was also transported. Atomic oxygen was transported from the lower thermosphere to several kilometers below in amounts higher than usual. The increased nitric oxide concentration in the stratosphere due to the transport catalytically destroyed the ozone in the region. The vertical transport rates were calculated to understand the speed of the descent. The low geomagnetic index in 2019, like in all years besides 2004, indicates that these events are attributed to unusual meteorology.
An SSW event took place in the southern hemisphere in 2019 during the Antarctic winter. This led to a large increase in temperature, which evaporated the Polar Stratospheric Clouds (PSCs). PSCs provide their surface for converting halogen reservoir species into ozone-destroying reactive forms. The absence of PSCs during and immediately after the SSW event led to a lower conversion of halogen reservoir species into reactive forms. Satellite instrument measurements agree with theoretical expectations. The 2002 SSW in the SH led to similar outcomes and are compared to the 2019 event. Large enhancements in ozone in 2019 led to the smallest ozone hole since ~ 1982.
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Using Self-Organizing Maps to Calculate Chilling Hours as an Indicator of Temperature Shifts During Winter in the Southeastern United StatesHenry, Parker Wade 24 May 2022 (has links)
Several warm winter events have occurred across the Southeast in the past decade, including 2 major events in 2017 and 2018 in Georgia and South Carolina. Plants will begin their spring growth sooner than climatology would suggest and then be damaged by early spring frosts in what is commonly known as a "false spring" event. Some species of plants, like peaches and blueberries, which produce buds early in the season, are just an example of some of the agricultural products more at risk than others. As an important measure of dormancy time in plants, chill hours present a measurement capable of tracking phenological shifts in plants. While a lack of required chill hours can delay spring emergence, intense warm periods can override the chilling hour requirement and induce spring emergence. This project involves training self-organizing maps (SOMs) to identify periods of anomalous winter warming based on a reduced number of chill hours within a 5-day temporal period compared to the period's climatological average. A second SOM is nested in the node that produced the most anomalous events to identify the range of warming that occurs in the most anomalous events, the synoptic setups of these events, and when these occurred. Hourly 2-meter temperature from ERA5 is used to conduct this analysis over a domain centered primarily over South Carolina and Georgia with a temporal period of 1980-2020. Climatological examination of chill hour accumulations in the past 4 decades show an overall decrease in chill hour accumulation across the past decade (2011-2020) Results indicated that periods of higher-than-average temperatures are increasing with time while periods of average or lower than average temperatures are decreasing with time. Both results were statistically significant by Mann-Kendall test. The results of the nested SOMs suggest that an increase in patterns of southerly flow (a common pattern for warmer temperatures) is occurring through time. A third SOM investigating early spring hard freezes was inconclusive but illustrated that some years had more early spring frosts than others independent of how many warmer than average periods occurred in the main winter. The use of SOMs for investigating climatological and synoptic changes in winter and early spring proved successful and effective. Future modifications to these SOMs could be used to identify more trends that exist within these seasons. / Master of Science / Several warm winter events have occurred across the Southeast in the past decade, including 2 major events in 2017 and 2018 in Georgia and South Carolina. Plants will begin their spring growth sooner than climatology would suggest and then be damaged by early spring frosts in what is commonly known as a "false spring" event. Some species of plants, like peaches and blueberries, which produce buds early in the season, are just an example of some of the agricultural products more at risk than others. As an important measure of dormancy time in plants, chill hours present a measurement capable of tracking shifts from normal winter to spring transition in plants. While a lack of required chill hours can delay leaf emergence and spring blooms, intense warm periods can override the chilling hour requirement and induce this spring emergence. This project involves training self-organizing maps (SOMs), a machine learning model, to identify periods of anomalous winter warming based on a reduced number of chill hours within a 5-day temporal period compared to the period's climatological average. A second SOM is nested in the node that produced the most anomalously warm events to identify the range of warming that occurs in the most anomalous events, the large-scale meteorological setups of these events, and when these occurred. Hourly 2-meter temperature from ERA5, a climatological dataset, is used to conduct this analysis over a domain centered primarily over South Carolina and Georgia with a temporal period of 1980-2020. Climatological examination of chill hour accumulations in the past 4 decades show an overall decrease in chill hour accumulation across the past decade (2011-2020) Results indicated that periods of higher-than-average temperatures are increasing with time while periods of average or lower than average temperatures are decreasing with time. Both of these trend findings were statistically significant by Mann-Kendall test. The results of the nested SOMs suggest that an increase in patterns of southerly flow (a common pattern for warmer temperatures) is occurring through time. A third SOM investigating early spring hard freezes (temperatures low enough to cause damage to plant cellular structures) was inconclusive but illustrated that some years had more early spring frosts than others independent of how many warmer than average periods occurred in the main winter. The use of SOMs for investigating climatological and synoptic changes in winter and early spring proved successful and effective. Future modifications to these SOMs could be used to identify more trends that exist within these seasons.
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The Present and Future of the Horn of Africa RainsSchwarzwald, Kevin January 2024 (has links)
Societies in much of the Horn of Africa are affected by variability in two distinct rainy seasons: the March-May (MAM) “long” rains and the October-December (OND) “short” rains. The region is the driest area of the tropics, while its societies are heavily dependent on the rainfall cycle. Especially worrying are anomalously dry conditions, which, together with other factors, contribute to food insecurity in the region. The recent 2020-2023 5-season drought, associated with the concurrent “triple-dip” La Niña and resulting in tens of millions of people facing “high levels of food insecurity” (cf: IGAD), renewed fears of long-term and possibly anthropogenically-forced drying trends, especially during the MAM long rains. A long-term decline in the long rains beginning in the early 1980s and lasting until the 2010s had indeed been noted in studies examining historical station-based observations, satellite observations, and farmer recollections in the region, though seasonal average rainfall has since partially recovered.
Consequently, global climate models (GCMs) are increasingly used to project changes in rainfall characteristics under global warming scenarios and associated impacts on societies, such as agricultural production, groundwater resources, and urban infrastructure, in addition to providing seasonal forecasts used for near-term decision-making. However, GCMs uniformly predict long-term wetting in both seasons despite observed drying trends in the long rains, an “East African Paradox” that complicates the ability of decisionmakers to plan for future rainfall conditions. Previous generations of GCMs have known biases in key dynamics of the regional hydroclimate. Decisionmakers relying on projections of future rainfall in the GHA therefore need to know whether current GCM projections are trustworthy. In other words, can we be confident in future modeled wetting trends in both the long and short rains?
This thesis pursues this question in three parts. Chapter 2 seeks to understand the fundamental dynamics affecting the East African seasonal rainfall climatology, which is unique for its latitude in both its aridity and for the dynamical differences between its two rainy seasons. I explain these characteristics through the climatology of moist static stability, estimated as the difference between surface moist static energy h? and midtropospheric saturation moist static energy h*. In areas and at times when this difference, h? − h*, is higher, rainfall is more frequent and more intense. However, even during the rainy seasons, h? − h* < 0 on average and the atmosphere remains largely stable, in line with the region’s aridity. The seasonal cycle of h? − h*, to which the unique seasonal cycles of surface humidity, surface temperature, and midtropospheric temperature all contribute, helps explain the double-peaked nature of the regional hydroclimate. Despite tropospheric temperature being relatively uniform in the tropics, even small changes in h* can have substantial impacts on instability; for example, during the short rains, the annual minimum in regional h* lowers the threshold for convection and allows for instability despite surface humidity anomalies being relatively weak. This h? − h* framework can help identify the drivers of interannual variability in East African rainfall or diagnose the origin of biases in climate model simulations of the regional climate.
Chapter 3 applies these results to conduct a process-based model evaluation of the ability of GCMs from the 6th phase of the Coupled Model Intercomparison Project (CMIP6, the latest GCM generation) to simulate the historical climatology and variability in the East African long and short rains. I find that key biases from the 5th phase of the Coupled Model Intercomparison Project (CMIP5) remain or are worsened, including long rains that are too short and weak and short rains that are too long and strong. Model biases are driven by a complex set of related oceanic and atmospheric factors, including simulations of the Walker Circulation. h? − h* is too high in models, requiring more instability for the same amount of rainfall than in observations. Biased wet short rains in models are connected with Indian Ocean zonal sea surface temperature (SST) gradients that are too warm in the west and convection that is too deep. Models connect equatorial African winds with the strength of the short rains, though in observations a robust connection is primarily found in the long rains. Model mean state biases in the timing of the western Indian Ocean SST seasonal cycle are associated with certain rainfall timing biases, though both biases may be due to a common source. Simulations driven by historical SSTs (so-called ‘AMIP’ runs) often have larger biases than fully coupled runs. However, models generally respond to teleconnections with the Indian Ocean Dipole and the El Niño Southern Oscillation in particular as expected, maintaining the possibility that trends in the long and short rains may also respond correctly to simulated trends in large-scale dynamics.
Finally, Chapter 4 applies these results to directly tackle the East African Paradox by analyzing model trends across the entire observational record to identify under what conditions they fail to reproduce observed trends. Since even with perfect models and observational records model output may differ from observations due to internal variability, I analyze the full spread of CMIP6 output, including Large Ensembles and totalling 598 runs from 47 models. I find that while observed trends are always within the model spread if all runs from all Large Ensembles are considered, the Paradox remains in CMIP6 models, since GCMs substantially underproduce strong drying trends compared to observations. Within the observational record, the Paradox is limited to the time period with the most anomalous drying trends (especially in the years 1980-2010); the recent recovery in rainfall falls comfortably within the range of GCM simulations.
The Paradox is not visible in AMIP runs forced with observed historical SSTs, suggesting that biases in simulations of SSTs may be part of the explanation, though clear causality remains elusive. The transition towards more biased trends from SST-forced to coupled runs can also be seen in output from hindcasts from seasonal forecast models, where trends calculated from short-lead-time projections (when the ocean state resembles observations) do not feature the Paradox, while lead times starting with 1.5 months do. More broadly, I show that climate model simulations of observed trends alone cannot be used to reject model predictions of increased (or decreased) precipitation under future forcings. Decision-makers relying on future projections of rainfall trends in East Africa will likely need to consider the possibility of further drying in addition to wetting trends from GCMs.
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Effect of various packing structure on gas absorption for enhanced CO2 captureRahmanian, Nejat, Rehan, M., Sumani, A., Nizami, A.S. 12 March 2021 (has links)
Yes / The increasing concentration of carbon dioxide (CO2) in the atmosphere is a primary global environmental concern due to its detrimental impacts on climate change. A significant reduction in CO2 generation together with its capture and storage is an imperative need of the time. CO2 can be captured from power plants and other industries through various methods such as absorption, adsorption, membranes, physical and biological separation techniques. The most widely used systems are solvent based CO2 absorption method. The aim of this study was to analyze the effect of various random and structured packing materials in absorption column on CO2 removing efficiency. Aspen plus was used to develop the CO2 capture model for different packing materials with Monoethanolamine (MEA) solvent in order to optimize the system. It was found that the lowest re-boiler duty of 3,444 kJ/KgCO2 yield the highest rich CO2 loading of 0.475 (mole CO2/mole MEA) by using the BX type of structured packing having the highest surface area. The surface area of the different packing materials were inversely proportional to the temperature profiles along the column. Furthermore, the packing materials with higher surface areas yielded higher CO2 loading profiles and vice versa. The findings of this study and recommendation would help further research on optimization of solvent-based CO2 capturing technologies.
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Climate warming effects on the life cycle of the parasite Ceratomyxa shasta in salmon of the Pacific NorthwestChiaramonte, Luciano V. 08 March 2013 (has links)
Aquatic ecosystems continue to be increasingly affected by climate warming. For salmonids in the Pacific Northwest of North America, increasing temperatures pose tighter thermal constraints on their habitat use as well as aspects of their individual performance, such as disease resistance. This thesis examines the effect of temperature on the phenology of the Ceratomyxa shasta life cycle, the effect of thermal refugia on disease risk in juvenile salmonids in the Klamath River, CA, and the spatial and temporal distribution of C. shasta in the Willamette River, OR. We developed a biological model that predicts an acceleration of the C. shasta life cycle development due to climate shifts in the Klamath River, resulting in more generations per year and earlier seasonal parasite occurrence. We showed that in early summer the Beaver Creek-Klamath River confluence provides juvenile Chinook and coho salmon an area of lower parasite doses and cooler temperatures than the main stem, thus lessening disease risk. By accelerating the development of C. shasta in its hosts, increasing temperatures will result in earlier parasite transmission to juvenile salmonids and a longer season of infectivity. These fish may find disease refuge at cold tributary inflows to the main stem of the Klamath River in early summer, further adding to the benefit of these important thermal habitats. To determine if similar disease
patterns occur in other rivers with the parasite, we described spatial and temporal occurrence of C. shasta in the Willamette River. By collecting weekly water sampling at four sites over 28 months we characterize seasonal and annual differences of parasite abundance, which varies with weekly temperature. We also collected samples along the length of the main stem and its tributaries and identified spatial differences in C. shasta spore densities. Identification of spatial and temporal variation of C. shasta in the Willamette River provides a foundation for understanding future patterns of disease occurrence in this river where conservation of anadromous fisheries is also of concern. This thesis identifies likely responses of C. shasta to climate warming in the Klamath River, with useful application to other rivers in the Pacific Northwest. / Graduation date: 2013
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Drought coping mechanisms : a case study of small scale farmers in Motheo district of the Free State provinceOlaleye, Olubunmi Leke 09 1900 (has links)
A case study on drought coping mechanisms was conducted among small-scale farmers in the
Motheo District of the Free State Province in Republic of South Africa, to determine how farmers
cope with drought effects with or without external influence in terms of drought relief packages
from the government and non-governmental organizations. Data was collected by administering a
semi-structured questionnaire to 200 farmers. The data were captured and analysed using SPSS to
obtain frequency, cross-tab, univariate ANOVA as well as logistic regression analysis.
Findings of the study revealed that only 12.5 percent of the respondents were aware of drought,
while a larger percentage of 87.5 of the respondents were not aware of a drought incidence before
its onset, which made them more vulnerable to the drought disaster; 8.5 percent of them protected
water sources for livestock while 91.5 percent of the farmers did not protect water sources for their
livestock because they farm on a communal land; 42.5 percent provided supplementary feeds to
livestock during the drought, but 57.5 percent did not provide supplementary feed for their animals
for lack of funds.
Ninety-nine (99.0) percent of the respondents shared grazing lands while only 1 per cent did not
because most farmers operates on a communal system of farming; 35.5 percent changed cropping
systems; 50.5 percent had alternative water sources for crops which included mini and hand
irrigation systems while 49.5 percent of the respondents depended solely on streams and rivers
available in the villages; 19.3 percent sold or pledged assets in order to be able to cope with
drought effects while most farmers did not pledge or sell assets not because they did not want to,
but because they did not have assets to sell. / Envornmental Science / Thesis (M.Sc. (Environmental Management))
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Awareness of global warming and car purchasing behavior in SingaporeNakayama, Chika 01 January 2008 (has links)
The purpose of this study was to determine consumers' attitudes toward and perceptions of global warming and hybrid cars and examine the car purchasing behavior in Singapore. The benefits of the study will provide marketers with insight of consumers' demand for cars in Singapore. Findings will help automakers develop more effective, consumer-oriented advertising plans for cars in Asia as Singapore consists of diverse Asian ethnic backgrounds- Chinese, Indian, and Malaysain.
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Drought coping mechanisms : a case study of small scale farmers in Motheo district of the Free State provinceOlaleye, Olubunmi Leke 09 1900 (has links)
A case study on drought coping mechanisms was conducted among small-scale farmers in the
Motheo District of the Free State Province in Republic of South Africa, to determine how farmers
cope with drought effects with or without external influence in terms of drought relief packages
from the government and non-governmental organizations. Data was collected by administering a
semi-structured questionnaire to 200 farmers. The data were captured and analysed using SPSS to
obtain frequency, cross-tab, univariate ANOVA as well as logistic regression analysis.
Findings of the study revealed that only 12.5 percent of the respondents were aware of drought,
while a larger percentage of 87.5 of the respondents were not aware of a drought incidence before
its onset, which made them more vulnerable to the drought disaster; 8.5 percent of them protected
water sources for livestock while 91.5 percent of the farmers did not protect water sources for their
livestock because they farm on a communal land; 42.5 percent provided supplementary feeds to
livestock during the drought, but 57.5 percent did not provide supplementary feed for their animals
for lack of funds.
Ninety-nine (99.0) percent of the respondents shared grazing lands while only 1 per cent did not
because most farmers operates on a communal system of farming; 35.5 percent changed cropping
systems; 50.5 percent had alternative water sources for crops which included mini and hand
irrigation systems while 49.5 percent of the respondents depended solely on streams and rivers
available in the villages; 19.3 percent sold or pledged assets in order to be able to cope with
drought effects while most farmers did not pledge or sell assets not because they did not want to,
but because they did not have assets to sell. / Envornmental Science / Thesis (M.Sc. (Environmental Management))
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Model Analysis of the Hydrologic Response to Climate Change in the Upper Deschutes Basin, OregonWaibel, Michael Scott 01 January 2010 (has links)
Considerable interest lies in understanding the hydrologic response to climate change in the upper Deschutes Basin, particularly as it relates to groundwater fed streams. Much of the precipitation occurring in the recharge zone falls as snow. Consequently, the timing of runoff and recharge depend on accumulation and melting of the snowpack. Numerical modeling can provide insights into evolving hydrologic system response for resource management consideration. A daily mass and energy balance model known as the Deep Percolation Model (DPM) was developed for the basin in the 1990s. This model uses spatially distributed data and is driven with daily climate data to calculate both daily and monthly mass and energy balance for the major components of the hydrologic budget across the basin. Previously historical daily climate data from weather stations in the basin was used to drive the model. Now we use the University of Washington Climate Impact Group's 1/16th degree daily downscaled climate data to drive the DPM for forecasting until the end of the 21st century. The downscaled climate data is comprised from the mean of eight GCM simulations well suited to the Pacific Northwest. Furthermore, there are low emission and high emission scenarios associated with each ensemble member leading to two distinct means. For the entire basin progressing into the 21st century, output from the DPM using both emission scenarios as a forcing show changes in the timing of runoff and recharge as well as significant reductions in snowpack. Although the DPM calculated amounts of recharge and runoff varies between the emission scenario of the ensemble under consideration, all model output shows loss of the spring snowmelt runoff / recharge peak as time progresses. The response of the groundwater system to changing in the time and amount of recharge varies spatially. Short flow paths in the upper part of the basin are potentially more sensitive to the change in seasonality. However, geologic controls on the system cause this signal to attenuate as it propagates into the lower portions of the basin. This scale-dependent variation to the response of the groundwater system to changes in seasonality and magnitude of recharge is explored by applying DPM calculated recharge to an existing regional groundwater flow model.
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