The identification and quantification of hydro-climatic cycles is important for un- derstanding land-atmosphere interactions, and is useful for evaluating the outputs of General Circulation Models (GCMs). This is particularly relevant in Southeast Asia, where tropical convection contributes a large influx of energy and moisture to the upper atmosphere. The analyses presented here cover interactions over a range of temporal scales, from diurnal to inter-annual. They also cover a range of spatial scales, including both observations and GCM outputs at inter-regional scales, and observations at intra-regional scales. Data Based M?delling (DBM) methods are used as an innovative way of iden- tifying climate signals from noisy data, and of estimating the uncertainties in complex environmental systems. Cycles and trends are identified using Dynamic Harmonic Regression, and rainfall and river discharges are investigated using Transfer Functions. To complement established DBM methods, a new approach is presented for analysing and comparing hydrograph peaks from different catchments . . For the inter-regional observational analyses, existing time series of observed net radiation, rainfall, latent heat flux and river discharge are obtained from typical , SE Asian regions. These series are used to identify temporal cycles and trends, and to evaluate inter-regional variations and their influences at different time scales. There are relatively few such studies available for the Tropics, so this investigation helps to fill a gap and to provide a baseline for evaluating future studies and/or GeM Land Surface Schemes (LSSs) are known to provide a POor repreSentation of climatic cycles in the humid tropics. For the inter-regional GeM model analyses, outputs from the UK Met Office HadGAMl model Were obtalned for the relevant SE Asian grid cells. These outputs were used to identify temporal dynamics in a similar way to the analysis of observations. The analysis of model outputs Was used to investigate how well the model simulates climate variability, and to explore the underlying physical processes. The analysis of intra-regional observations presents a comparison of rainfall and catchment discharges within a particular tropical region, namely the Danum Valley, in the Sabah region of Borneo. The analysis focuses on high-resolution variability in different-sized catchments, in an attempt to target the temporal and spatial resolution that characterises the humid tropics but is less well represented by LSSs within climate models.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:552837 |
| Date | January 2009 |
| Creators | Garcia, Maria Angeles Solera |
| Publisher | Lancaster University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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