<p> The radiation balance at a ship station in the eastern tropical Atlantic Ocean is calculated using a term-by-term approach. Irradiances are calculated using upper air data from four daily radiosonde ascents and hourly surface weather observations made at the Canadian vessel 'Quadra' during GATE Phase 1 (June- July, 1974).</p> <p> Global irradiance is calculated by a cloud layer model similar to that used by Davies et al in Southern Ontario, Canada. The model considers first, cloudless sky attenuation of solar irradiance by water vapour, ozone and Rayleigh scattering. Second, cloud effects are added by considering contributions from three cloud layers - high, middle and low and secondary radiation from cloud base of reflected surface radiation. Reflected solar irradiance is calculated using a mean sea-surface albedo of 6% suggested by Payne for that part of the Atlantic Ocean.</p> <p> Estimates of incoming longwave irradiance are made first, from a numerical flux emissivity model which uses radiosonde ascent data and cloud amount at three heights and second, from a simple model which uses surface temperature and total cloud amount.</p> <p> Outgoing longwave emittance is evaluated using surface temperature and an emissivity of 0.98. The radiation balance is then obtained as the algebraic sum of the four components.</p> <p> The estimated values are compared with values measured at 'Quadra'. In 70% of the cases, calculated and measured solar irradiance agree to within 20%. Model performance for cloud amount > 5/10 is least satisfactory.</p> <p> In all cases, model and measured values of daily incoming longwave irradiance agree to within 5%. In 60% of the cases, measured and calculated radiation balance agree to within 20%.</p> / Thesis / Master of Science (MSc)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/20380 |
| Date | 11 1900 |
| Creators | Uboegbulam, Timothy Chukuemeka |
| Contributors | Davies, J. A., Geography |
| Source Sets | McMaster University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis |
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