Environmental Signals in Satellite Altimeter Data

This document a progression of research, which demonstrates a connection between satellite radar altimeter data and and environmental activity over land surfaces. Variations in height and sigma0 data sets are both considered with the first stages being investigations into the reliability of the altimeter data over land. The accuracy of the height data eis considered in comparison to a number of existing Global Digital Elevation Models, this is made possible by the small effective footprint of the altimeter over land. Having shown the consistency of the altimeter height data, and confirmed creation of a very 'clean' data set using the export system approach, an investigation of sigma0 was carried out. Initially, this focused on locating areas of the world where sigma0 shows little variation with time, these areas are relatively small since over most regions of the Earth sigma0 varies rapidly on both spatial and temporal scales. These regions are identified both for calibration purposes and because any variation in sigma0 caused by environmental events would show up clearly against the almost constant background. Having identified a number of areas where sigma0 variation is small, a first land cross calibration between the ERS-1 and ERS-2 sigma0 data from Tandem Mission is described. These calibration areas are also used in an attempt to assess the anomaly in ERS-2 sigma0 reported by the European Centre for Medium range Weather forecasting during January 2000. Having assessed the consistency of the altimeter height and sigma0 data over a variety of land surfaces, a number of comparisons between the altimeter sigma0 data and different ground based environmental data sets are described. These comparisons show that although it is relatively simple to identify large-scale seasonal variations in rainfall, proving that altimeter sigma0 variations can be used to detect smaller scale events is much more problematic and requires sophisticated modelling. The final study described assess the potential of the ERS altimeters for monitoring river levels as a secondary indication of environmental events. The basis of this idea is that the river networks should integrate the rainfall over the catchment area and so make it possible to study environmental events using the 35-day data. Once a technique in both South America and Africa and found to provide results consistent with the known climcate data for these regions.

Name dc:type.qualificationname

PhD

Level dc:type.qualificationlevel

Doctoral

Grantor dc:publisher.institution

De Montfort University

Year dc:date.issued

2002

Author dc:creator

• Pinnock, Ralph Allen

Licence

• https://dora.dmu.ac.uk/bitstreams/e99ec8a7-7169-4d2c-b36b-0c78bb81cb90/download