The increasing levels of the greenhouse gas carbon dioxide (CO2) in the Earths atmosphere, caused by human release of CO2, has made it desirable to understand the factors determining the CO2-variation because of CO2’s warming effect on the Earths temperature which will change the premises of all life on earth.The purpose of this investigation is to understand the effects of the largest factors of influence on the CO2-concentration – like sea, vegetation and anthropogenic outlets – in the Baltic Sea region, and possible surprises from the results. To be able to do this only from CO2-measurements some assumptions have to be done as starting point. Such are that, besides from the yearly trend of the CO2-concentration and the variation of oceanic influence, monthly variation only is caused by vegetation and that the yearly offset in CO2-levels only is affected by anthropogenic outlets. These factors are together called the local season and will be used for evaluation of the CO2-values for each site. This analysis is done for eight sites surrounding the Baltic Sea region and is compared with results from the site of Östergarnsholm, an island in the Baltic Sea east of Gotland.The results show that stations with high vegetational influence has high amplitudes for the local season compared to sites more influenced by sea. This also makes the amplitude to be connected with latitude since sites with longer growing season is surrounded by higher density of vegetation. The minimum for the local season is also dependent on the growing season, since it occurs when the vegetational consumption is largest. Peaks in the local season can be seen in connection with the maximum decay of the natural vegetation in the early winter months, and with the planting and harvest season for agricultural land. Considering the effect from anthropogenic influence a clear connection in the offset of the local season can be seen, with higher offsets for sites of higher anthropogenic influence and vice versa. Anthropogenic influence also seems to give raised values in summer for the local season, indicating that the variation of the local season cannot be simply connected to only vegetational influence. For variability, higher values in the summer months are seen for the anthropogenic sites, while in winter the variability is more similar for all sites. This might be connected with a higher degree of local influence during summers, which for anthropogenic stations leads to high variability due to inhomogenous surroundings…
Contents
1. INTRODUCTION
2. SITES AND MEASUREMENTS
2.1 WDCGG SITES
2.1.1 World Data Center for Greenhouse Gase
2.1.2 Site locations and local conditions
2.1.3 Other general properties of the stations
2.1.4 Measurements
2.1.5 Data periods
2.2 THE ÖSTERGARNSHOLM SITE
2.2.1 Data periods
2.2.2 Instrumentation and measurements
3. THEORY
3.1 THE CARBON CYCLE
3.1.1 Long-term global trend
3.1.2 Seasonal variation
3.2 FACTORISATION OF CO2-VARIATION
3.2.1 Terms of importance for the CO2-concentration
3.2.2 Assumptions
3.2.3 Expression for the CO2-variation
3.3 RENDERING THE TERMS FROM DATA
3.3.1 Getting an expression for Ctrend
3.3.2 Getting an expression for CM’
3.3.3 Extracting the local values of Cveg’ and ant C
3.4 EVALUATION OF LOCAL SEASON RESULTS
3.5 PREDICTING THE LOCAL SEASON CHARACTER FOR LOCATIONS IN THE BALTIC SEA REGION
3.6WD-EVALUATION
3.6.1 Choice of WD-sectors
4. RESULTS FROM THE WDCGG-STATIONS
4.1 REMOVING THE GLOBAL TREND OF CO2
4.1.1 The global trend
4.1.2 Variation with global trend removed
4.2 THE SEASONAL VARIATIONS AND THE REMOVING OF CM’
4.2.1 The temporal deviation of station M
4.3 THE LOCAL SEASON VARIATIONS
4.3.1 ant C -offset
4.3.2 Cveg’-amplitude
4.3.3 Cveg’-min
4.3.4 Cveg’-max
4.4 ANALYSE OF MEAN DEVIATIONS FOR HOURLY VARIATIONS
4.5 PREDICTING THE LOCAL SEASON OF CO2 FOR ÖSTERGARNSHOLM
4.5.1 ant C -offset
4.5.2 Cveg’ -amplitude
4.5.3 Cveg’ -min
4.5.4 Cveg’ -max
5. RESULTS FOR ÖSTERGARNSHOLM
5.1 CORRECTION OF THE ÖSTERGARNSHOLMS-DATA
5.2 PROCESS OF ELIMINATION
5.3 THE LOCAL SEASON
5.3.1 ant C -offset
5.3.2 Cveg’-amplitude
5.3.3 Cveg’-min
5.3.4 Cveg’-max
5.3.5 Resulting correction of the average local season of Östergarnsholm
5.4 ANALYSE OF MEAN DEVIATIONS
5.5 EVALUATION BY WD-CATEGORISATION
5.5.1 Reliability of monthly data for the WD-sectors
5.5.2 Local seasons for the WD-sectors
6. DISCUSSION
6.1 SURPRISES IN CVEG’-AMPLITUDE
6.2 IMPROVEMENTS
6.2.1 Tracer measurements
6.2.2 Data amount
6.2.3 Further investigations
7. SUMMARY AND CONCLUSION
ACKNOWLEDGEMENTS
REFERENCES
Author: Astrom, Gustav
Source: Uppsala University Library
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